Heat recovery system

Abstract

The present invention provides a waste heat recovery system that can recover waste heat even if it is unstable, while suppressing the occurrence of heat pump shutdowns and failures, and can recover heat even under severe conditions where the amount of heat changes significantly. [Solution] The waste heat recovery device 1 includes three heat pumps 10 that supply hot water to the hot water circuit and receive it from the hot water circuit, and supply chilled water to the chilled water circuit and receive it from the chilled water circuit, and a control unit 90 that controls the hot water and chilled water. The chilled water is heated by a waste heat medium E, which is a medium that has waste heat. The control unit 90 is connected to a waste heat amount detection unit (flow meters 65, 73, temperature sensors 66, 74) that detects the amount of heat in the waste heat medium E. Based on the amount of heat detected by the waste heat amount detection unit, the control unit 90 controls at least one of the waste heat medium, hot water and chilled water.

Description

[Technical Field]

[0001] This disclosure relates to a waste heat recovery device capable of recovering waste heat. [Background technology]

[0002] Japanese Patent Publication No. 2016-161248 (Patent Document 1) discloses a heat pump type steam generator. This device comprises a heat pump section 16 that circulates a refrigerant by connecting a heat recovery unit 20, a compressor 22, a condenser 24, and a throttling expander 26 in a ring, a hot water supply section 18 that supplies hot water to the heat recovery unit 20 and discharges it, and a steam generator section 14 that supplies water to be heated to the condenser 24 and heats the water with a refrigerant to generate steam. Furthermore, it comprises a heat quantity monitoring section 44 that monitors the amount of heat in the hot water supplied to the heat recovery unit 20 by the hot water supply section 18, and a control section 19 that controls the flow rate of at least one of the hot water and refrigerant based on the monitoring results from the heat quantity monitoring section 44. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-161248 [Overview of the project] [Problems that the invention aims to solve]

[0004] When recovering waste heat with a heat pump, the waste heat is actually unstable, making it difficult to maintain stable operation of the heat pump. For example, if the waste heat is waste hot water from a factory, the temperature and flow rate of the waste hot water may change depending on the manufacturing process. Depending on the degree of these changes, the balance between hot and cold may not be maintained in the heat recovery heat pump, potentially leading to the heat pump stopping or failing. Furthermore, under severe conditions where the amount of waste heat fluctuates significantly, for example between the maximum amount (100%) and a minimum amount of about 20% (80% reduction), attempting to recover such waste heat with a single heat pump will result in the heat pump's output fluctuating significantly, similar to the amount of waste heat, making it difficult to provide a stable supply of hot water from the heat pump.

[0005] One of the main objectives of this disclosure is to provide a waste heat recovery device that can recover waste heat, even if it is unstable, while suppressing the occurrence of heat pump shutdowns and failures. Another main objective of this disclosure is to provide a waste heat recovery system that can recover waste heat even under harsh conditions in which its heat content changes significantly. [Means for solving the problem]

[0006] This specification discloses a waste heat recovery system. This waste heat recovery system may include one or more heat pumps that supply hot water to a hot water circuit and receive it from the hot water circuit, and supply chilled water to a chilled water circuit and receive it from the chilled water circuit. The waste heat recovery system may include a control unit that controls the hot water and chilled water. The chilled water may be heated by a waste heat medium, which is a medium that contains waste heat. The control unit may be connected to a waste heat quantity detection unit that detects the amount of heat in the waste heat medium. The control unit may control at least one of the waste heat medium, hot water and chilled water based on the amount of heat from the waste heat quantity detection unit. [Effects of the Invention]

[0007] One of the main effects of this disclosure is the provision of a heat recovery system that can recover waste heat, even if it is unstable, while suppressing the occurrence of heat pump shutdowns and failures. Another key effect of this disclosure is the provision of a waste heat recovery system that can recover waste heat even under harsh conditions in which its heat content changes significantly. [Brief explanation of the drawing]

[0008] [Figure 1] It is a block diagram of an exhaust heat recovery device according to the first aspect of the present disclosure. [Figure 2] It is a flowchart related to an operation example of the exhaust heat recovery device of FIG. 1. [Figure 3] It is a flowchart leading to FIG. 2. [Figure 4] It is a block diagram of an exhaust heat recovery device according to the second aspect of the present disclosure. [Figure 5] It is a flowchart related to an operation example of the exhaust heat recovery device of FIG. 4. [Figure 6] It is a flowchart leading to FIG. 5. [Figure 7] It is a block diagram of an exhaust heat recovery device according to the third aspect of the present disclosure. [Figure 8] It is a flowchart related to an operation example of the exhaust heat recovery device of FIG. 7. [Figure 9] It is a flowchart leading to FIG. 8. [Figure 10] It is a block diagram of an exhaust heat recovery device according to the fourth aspect of the present disclosure. [Figure 11] It is a flowchart related to an operation example of the exhaust heat recovery device of FIG. 10. [Figure 12] It is a flowchart leading to FIG. 11. [Figure 13] It is a block diagram of an exhaust heat recovery device according to the fifth aspect of the present disclosure. [Figure 14] It is a block diagram of an exhaust heat recovery device according to the sixth aspect of the present disclosure. [Figure 15] It is a block diagram of an exhaust heat recovery device according to the seventh aspect of the present disclosure. [Figure 16] It is a block diagram of an exhaust heat recovery device according to the eighth aspect of the present disclosure. [Figure 17] It is a block diagram of a heating and cooling device according to the ninth aspect of the present disclosure. [Figure 18] It is a flowchart related to an operation example of the heating and cooling device of FIG. 17. [Figure 19] It is a flowchart leading to FIG. 18. [Figure 20]It is a block diagram of a heating and cooling device according to a tenth aspect of the present disclosure. [Figure 21] It is a flowchart according to an operation example of the heating and cooling device of FIG. 20. [Figure 22] It is a flowchart leading to FIG. 21. [Figure 23] It is a block diagram of a heating and cooling device according to an eleventh aspect of the present disclosure. [Figure 24] It is a flowchart according to an operation example of the heating and cooling device of FIG. 23. [Figure 25] It is a flowchart leading to FIG. 24. [Figure 26] It is a block diagram of a heating and cooling device according to a twelfth aspect of the present disclosure. [Figure 27] It is a flowchart according to an operation example of the heating and cooling device of FIG. 26. [Figure 28] It is a flowchart leading to FIG. 27. [Figure 29] It is a flowchart according to an operation example of a heating and cooling device according to a thirteenth aspect of the present disclosure. [Figure 30] It is a flowchart leading to FIG. 29. [Figure 31] It is a block diagram of a heating and cooling device according to a fourteenth aspect of the present disclosure. [Figure 32] It is a flowchart according to an operation example of the heating and cooling device of FIG. 31. [Figure 33] It is a flowchart leading to FIG. 32.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments and modification examples of the present disclosure will be described as appropriate based on the drawings. Note that the present disclosure is not limited to the following embodiments and modification examples.

[0010] [First Embodiment] FIG. 1 is a block diagram of an exhaust heat recovery device 1 according to a first aspect of the present disclosure. The waste heat recovery device 1 is installed in a factory where both a heating load H (the object to be heated) and waste heat (the object to be recovered) may be present. Furthermore, the waste heat recovery device 1 may be installed in facilities other than factories. Also, the heating load H may include only one individual heating load, such as heating a single furnace, or it may include multiple individual heating loads, such as heating a furnace and heating a drying device. These and other examples of modifications are applicable to other forms as appropriate.

[0011] The waste heat recovery device 1 is equipped with a waste heat recovery type heat pump 10 that simultaneously supplies hot water for heating a heating load H and cools the waste heat medium E with chilled water for waste heat recovery. The waste heat medium E is a medium that contains waste heat. The heat pump 10 generates chilled water and simultaneously generates hot water using the heat generated in the process, and supplies each to the outside. For example, a heat pump (Mitsubishi Heavy Industries Ltd. hot water heat pump ETW-L) capable of simultaneously supplying chilled water at a temperature of approximately 5-45°C and hot water at a temperature of approximately 50-90°C is used. In addition, multiple heat pumps 10 (three in this case) are used. Each heat pump 10 supplies hot water and chilled water. The heat pump 10 has the characteristic of simultaneously supplying hot and cold water, which is then sufficiently heated and returned to the surface, and then heated and cooled again. Therefore, it is necessary to maintain a balance between the hot and cold water. In order to extract a large amount of hot water, the heat from the hot water must be sufficiently absorbed by the target and returned, and a large amount of cold water must also be extracted, sufficiently heated, and returned. Furthermore, at least one of the heat pumps 10 may be capable of supplying hot water up to 90°C, or capable of supplying hot water at 95°C using 30°C cold water (waste hot water). Also, the number of heat pumps 10 may be one, two, or four or more. These modifications can also be applied to other embodiments and modifications.

[0012] Each heat pump 10 is connected to a pipe 12 that supplies hot water as a heating medium to the heating load H side, and to a pipe 16 that supplies chilled water as a cooling medium to the heat exhaust medium E side. A temperature sensor 17, which acts as a chilled water temperature detection unit, is interposed in the pipe 16 of the first heat pump 10. The temperature sensor 17 is capable of detecting a fifth temperature T5. The fifth temperature T5 is the temperature of the chilled water in the pipe 16 of the first heat pump 10. A temperature sensor 18, which acts as a chilled water temperature detection unit, is interposed in the pipe 16 of the second heat pump 10. The temperature sensor 18 is capable of detecting a sixth temperature T6. The sixth temperature T6 is the temperature of the chilled water in the pipe 16 of the second heat pump 10. A temperature sensor 19, which acts as a chilled water temperature detection unit, is interposed in the pipe 16 of the third heat pump 10. The temperature sensor 19 is capable of detecting a seventh temperature T7. The seventh temperature T7 is the temperature of the chilled water inside the pipe 16 of the third heat pump 10. Furthermore, each heat pump 10 is connected to a pipe 22 that returns hot water from the heating load H side to the heat pump 10, and to a pipe 26 that returns chilled water from the heat exhaust medium E side to the heat pump 10. A pump 23 for supplying hot water is interposed in each pipe 22. A pump 27 for supplying chilled water is interposed in each pipe 26.

[0013] Each pipe 12 is combined into a single pipe 33 that connects to the heat exchanger 32 on the heating load H side. The heat exchanger 32, acting as a hot water side heat exchanger, performs heat exchange between the hot water in pipe 33 and the hot water in the hot water circuit on the heating load H side, i.e., the heating load side hot water. The hot water in pipe 33 heats the hot water on the heating load H side. The hot water that has undergone heat exchange exits the heat exchanger 32 passes through pipe 34 and branches into each pipe 22. The hot water side circuit for each heat pump 10 includes each pipe 12, pipe 33, heat exchanger 32, pipe 34, each pipe 22, and each pump 23. Furthermore, regardless of whether it is the hot water side, cold water side, heating load H side, cooling load C side, etc., each pipe may be fitted with at least one of a heat exchanger and / or a tank, which are not shown. Also, the arrangement of at least one of the various pipes, pumps, and tanks may be changed or omitted as appropriate.

[0014] The circuit on the heating load H side includes a hot water tank 40, pipes 41 and 42, a pump 43, pipes 44 and 45, a pipe 46, a supply passage 47 for supplying steam J as another heat source, and a steam control valve 48. The hot water tank 40 stores hot water on the heating load side. The hot water tank 40 has an internal heat exchanger 50. Pipe 41 is connected to the heat exchanger 32 and the hot water tank 40, and carries the heating load side hot water from the heat exchanger 32 to the hot water tank 40. The heat exchanger 32 heats the heating load side hot water in the hot water tank 40. Pipe 42 is connected to the hot water tank 40 and the heat exchanger 32, and carries hot water on the heating load side from the hot water tank 40 to the heat exchanger 32. Pump 43, acting as a hot water pump on the heating load side, is interposed in pipe 42 and delivers hot water on the heating load side. Pump 43 can adjust the flow rate of the hot water on the heating load side and can adjust the heat quantity of the hot water on the heating load side. Pipe 44 is connected to the hot water tank 40 and the heating load H, and passes hot water from the hot water tank 40 to the heating load H. Pump 45 is installed in pipe 44 and delivers hot water to the heating load side. Pump 45 can adjust the flow rate of the hot water to the heating load side and can adjust the heat content of the hot water to the heating load side. Pipe 46 is connected to the heating load H and the hot water tank 40, and carries hot water from the heating load H to the hot water tank 40. The supply line 47 is connected to the in-tank heat exchanger 50 and passes steam J to the in-tank heat exchanger 50. The steam J is heated by heat exchange with the hot water on the heating load side in the hot water tank 40 in the in-tank heat exchanger 50, thereby heating the hot water. The steam control valve 48 adjusts the amount of steam J supplied to the heat exchanger 50 inside the tank, thereby adjusting the amount of hot water heated by the heating load from other heat sources. The tank's internal heat exchanger 50 is connected to a discharge channel 51 that discharges the steam J (including the water that has been converted) after heat exchange. Furthermore, as an alternative heat source, electric heaters, air-cooled heat pumps, or combinations thereof may be used instead of steam J, or in conjunction with steam J.

[0015] Furthermore, each of the pipes 16 on the heat dissipation medium E side is combined into a single pipe 60. Pipe 60 is connected to the first heat dissipation heat exchanger 61 and carries chilled water from each heat pump 10. A temperature sensor 62 is interposed in pipe 60 as a chilled water temperature detection unit. The temperature sensor 62 is capable of detecting a first temperature T1. The first temperature T1 is the temperature of the chilled water in pipe 60. The first heat exchanger 61 for waste heat exchanges the heat of the process cooling water E1, which belongs to the waste heat medium E, with the heat of the chilled water from each heat pump 10. The process cooling water E1 is the cooling water used for cooling in a predetermined process. The first heat exchanger 61 for waste heat is connected to a pipe 63 for receiving process cooling water E1 and a pipe 64 for discharging the process cooling water E1 after heat exchange. A flow meter 65, which acts as a waste heat medium flow rate detection unit, and a temperature sensor 66, which acts as a waste heat medium temperature detection unit, are interposed in pipe 63. The flow meter 65 measures a first flow rate F1. The first flow rate F1 is the flow rate of the process cooling water E1. The temperature sensor 66 can detect a twelfth temperature T12. The twelfth temperature T12 is the temperature of the process cooling water E1 in pipe 63. In addition, a temperature sensor 67, which acts as a waste heat medium temperature detection unit, is interposed in pipe 64. The temperature sensor 67 can detect an eleventh temperature T11. The eleventh temperature T11 is the temperature of the process cooling water E1 in pipe 64. Here, temperatures 8 through 9 and 13 through 20 are all missing in the first form, but may be added as appropriate in the second form and beyond. The amount of heat in the process cooling water E1 entering the first heat exchanger 61 is determined by the first flow rate F1 and the twelfth temperature T12. The amount of heat in the process cooling water E1 leaving the first heat exchanger 61 is determined by the first flow rate F1 and the eleventh temperature T11. The flow meter 65 and temperature sensor 66, and the flow meter 65 and temperature sensor 67 are heat dissipation detection units that detect the amount of heat in the process cooling water E1. Furthermore, the entire amount of process cooling water E1 in the factory may be flowed through pipe 63 and introduced into the first heat exchanger 61 for waste heat, or a portion of the process cooling water E1 in the factory may be flowed through pipe 63 and introduced into the first heat exchanger 61 for waste heat by installing a branch pipe that branches off from the main pipe (not shown) through which the process cooling water E1 flows. Also, the heat quantity of the process cooling water E1 may be determined by only the 11th temperature T11 or the 12th temperature T12, for example, when the flow rate is stable, or by only the first flow rate F1, for example, when the temperature is stable.

[0016] Furthermore, a pipe 68 is connected to the first heat exchanger 61 for heat dissipation, through which chilled water after heat exchange passes. A temperature sensor 69 is interposed in the pipe 68 as a chilled water temperature detection unit. The temperature sensor 69 is capable of detecting a third temperature T3. The third temperature T3 is the temperature of the chilled water in the pipe 68. A second heat exchanger 70 for waste heat is connected to pipe 68. The second heat exchanger 70 exchanges heat between the waste hot water E2 belonging to the waste heat medium E and the chilled water from each heat pump 10 that has passed through the first heat exchanger 61. The waste hot water E2 is hot water used for heating or other purposes in a predetermined process. The second heat exchanger 70 for waste heat is connected to a pipe 71 for receiving waste hot water E2 and a pipe 72 for discharging the waste hot water E2 after heat exchange. A flow meter 73, which acts as a waste heat medium flow rate detection unit, and a temperature sensor 74, which acts as a waste heat medium temperature detection unit, are interposed in pipe 71. The flow meter 73 measures the second flow rate F2. The second flow rate F2 is the flow rate of the waste hot water E2. The temperature sensor 74 can detect the 22nd temperature T22. The 22nd temperature T22 is the temperature of the waste hot water E2 in pipe 71. In addition, a temperature sensor 75, which acts as a waste heat medium temperature detection unit, is interposed in pipe 72. The temperature sensor 75 can detect the 21st temperature T21. The 21st temperature T21 is the temperature of the waste hot water E2 in pipe 72. The amount of heat in the waste hot water E2 entering the second waste heat exchanger 70 is determined by the second flow rate F2 and the 22nd temperature T22. The amount of heat in the waste hot water E2 coming out of the second waste heat exchanger 70 is determined by the second flow rate F2 and the 21st temperature T21. The flow meter 73 and temperature sensor 74, and the flow meter 73 and temperature sensor 75 are waste heat quantity detection units that detect the amount of heat in the waste hot water E2. Furthermore, the entire amount of waste hot water E2 in the factory may be flowed through pipe 71 and introduced into the second waste heat exchanger 70, or a portion of the waste hot water E2 in the factory may be flowed through pipe 71 and introduced into the second waste heat exchanger 70 by installing a branch pipe that branches off from the main pipe (not shown) through which the waste hot water E2 flows. Also, the heat quantity of the waste hot water E2 may be determined by only the 21st temperature T21 or the 22nd temperature T22, for example, when the flow rate is stable, or by only the second flow rate F2, for example, when the temperature is stable. Moreover, the waste heat medium E is not limited to a combination of process cooling water E1 and waste hot water E2, but may be either one of these, or may be combined with other types of waste heat. Other types of waste heat include at least one of the following: waste hot water, makeup water, exhaust, exhaust gas, heat dissipation from equipment, heat dissipation from workpieces, waste heat from air conditioning (cooling water), or waste heat from cogeneration; or heat dissipation from various equipment (heat recovery by fan coils, etc.) and at least one of hydraulic fluid; or heat dissipation from workpieces after drying, etc.; heat transferred to the wash water when a product heated by hot water washing is washed in a subsequent water washing process; or waste heat generated from factory air conditioning (return of cold water); or combinations thereof.

[0017] The waste heat from process cooling water E1 is more stable than the waste heat from waste hot water E2. The heat energy of process cooling water E1 is more stable than the heat energy of waste hot water E2. Regarding thermal stability, for example, this corresponds to a daily fluctuation range of 10°C, 6°C, or 2°C in temperature, or a flow rate range of 10%, 6%, or 2% of the maximum flow rate, or a combination thereof.

[0018] Furthermore, a pipe 80 is connected to the second heat exchanger 70 for waste heat, through which chilled water after heat exchange passes. Each pipe 26 of each heat pump 10 is connected to pipe 80. Pipe 80 branches out to each pipe 26. Temperature sensors 81 and 82 are interposed in pipe 80 as chilled water temperature detection units. Temperature sensor 81 is capable of detecting a fourth temperature T4. The fourth temperature T4 is the temperature of the chilled water on the upstream side of pipe 80, i.e., on the side of the second heat exchanger 70 for exhaust heat. Temperature sensor 82 is capable of detecting a second temperature T2. The second temperature T2 is the temperature of the chilled water on the downstream side of pipe 80, i.e., on the side of each heat pump 10. The chilled water side circuit for each heat pump 10 includes each pipe 16, pipe 60, first heat exchanger 61 for exhaust heat, pipe 68, second heat exchanger 70 for exhaust heat, pipe 80, each pipe 26, and each pump 27. Furthermore, equipment for cooling the cooling load in the factory may be placed on the heat dissipation medium E side.

[0019] The heat recovery device 1 is equipped with a control unit 90. The control unit 90 controls various components and parts related to the heat recovery device 1. The control unit 90 is, for example, a computer. The control unit 90 may be an independent device, or it may be incorporated into one other component, such as being shared with the control unit of the heat pump 10, or it may be distributed and arranged in multiple other components. Each heat pump 10 is connected to the control unit 90. Flow meters 65 and 73 are also connected to the control unit 90. Furthermore, temperature sensors 17-19, 62, 66-67, 69, 74-75, and 81-82 are connected to the control unit 90. Other components may be connected to the control unit 90 as appropriate. In addition, a temperature sensor for detecting the temperature of hot water may be provided as a hot water temperature detection unit, similar to at least one of the temperature sensors 17-19, 62, 69, and 81-82 which are used as a chilled water temperature detection unit.

[0020] An example of the operation of such a waste heat recovery device 1 will be described below. Figures 2 and 3 are flowcharts relating to the example of this operation.

[0021] Each heat pump 10 can communicate current rotational speed information, which is information related to its current rotational speed, to the control unit 90. The control unit 90 can also send an operating rotational speed command, which is a command specifying the rotational speed at which the heat pump 10 should operate, to each heat pump 10. When each heat pump 10 receives an operating rotational speed command, it operates at the specified rotational speed. The rotational speed of each heat pump 10 corresponds to the load factor, and the load factor increases as the rotational speed increases. The load factor is the ratio of the current load to the maximum load that can be operated. The relationship between the rotational speed and load factor of each heat pump 10 (rotational speed load factor database) is stored in a memory unit (not shown) embedded in the control unit 90. Note that the memory unit is independent of the control unit 90, or it may be connected to the control unit 90. Furthermore, each heat pump 10 can receive an upper limit on its rotational speed and operate within that limit. That is, each heat pump 10 can be controlled to a maximum load within the range of its maximum load limit. Furthermore, the first temperature T1 for the chilled water is assumed to be around 20°C, and the second temperature T2 is assumed to be around 30°C. In addition, the inlet temperature for the heat exchanger 32 on the hot water side is assumed to be around 80°C, and the outlet temperature is assumed to be around 70°C. Furthermore, the temperature of the hot water in the hot water tank 40 is assumed to be around 70°C.

[0022] Furthermore, the maximum load limit for all three heat pumps 10 can be set to the same value collectively by the control unit 90. Each heat pump 10 operates to approach the set value of the hot water supply temperature. The control unit 90 sets the number of operating heat pumps 10 as follows: When the hot water supply temperature falls 2°C below the set value, the number of operating heat pumps increases by 1. When the hot water supply temperature rises 2°C above the set value, the number of operating heat pumps decreases by 1. When the load factor of heat pump 10 is 85% or higher, the number of operating units is increased by 1, and when the load factor is 30% or lower, the number of operating units is decreased by 1. A timer to prevent a continuous increase in the number of operating units, which detects the elapsed time from the start of operation when the number of operating units increases by 1 (i.e., 1 unit is added), and prevents further increases in the number of operating units before that time has elapsed, has a start delay timer, and the predetermined time is set to 4 minutes. A timer to prevent a continuous decrease in the number of operating units, which detects the elapsed time from the stop of operation when the number of operating units decreases by 1 (i.e., 1 unit is removed), and prevents further decreases in the number of operating units before that time has elapsed, has a stop delay timer, and the predetermined time is set to 4 minutes. Furthermore, at least one of the various temperatures or at least one of the various setting values ​​may be changed as appropriate, and the same applies to other configurations.

[0023] As shown in Figure 2, when an operation command for each heat pump 10 (HP) is input to the control unit 90 (YES in step S1), the flow rate of the process cooling water E1, i.e., the first flow rate F1, is set to a predetermined value (here, 21 m³). 3 ) or not is determined (Step S2). In Step S2, it is determined that the factory process, which is the source of the process cooling water E1, is relatively stable and that the heat and cold balance of each heat pump 10 can be maintained by the waste heat of the process cooling water E1. Here, the process cooling water E1 is defined as 150m at an average temperature of 34°C in the summer. 3 / h (cubic meters per hour), 70m in winter at an average temperature of 20°C. 3 A flow rate of approximately / h is expected. In addition, the wastewater hot water E2 is expected to be 3-20 m³ at a temperature of 20-40°C or lower. 3 A value of approximately / h is assumed. Unless otherwise specified, "a~b" indicates a value greater than or equal to a and less than or equal to b. However, at least one of the temperature and flow rate of the process cooling water E1 is not limited to such values. The same applies to various other values ​​such as the threshold values ​​for the temperature range and flow rate range of the waste hot water E2. If the answer in step S2 is YES, the control unit 90 starts hot water-based operation of each heat pump 10 (step S3). The start of operation of each heat pump 10 when the first flow rate F1 is equal to or greater than a predetermined flow rate corresponds to the production process being stable, the process cooling water E1 being stable, and sufficient exhaust heat from the exhaust heat medium E being available to maintain a balance of cooling and heating in each heat pump 10. Hot water-based operation is an operation in which the hot water is controlled to satisfy predetermined control objectives. These objectives include, for example, ensuring that at least one of the hot water temperature and / or the amount of heat generated by the hot water remains constant or within a predetermined range. Hot water-based operation can also be called hot water-following operation. Cold water-based operation, on the other hand, is an operation in which the cold water is controlled to satisfy predetermined control objectives.

[0024] Then, if a stop command to stop the operation of each heat pump 10 is input to the control unit 90 (YES in step S4), the control unit 90 stops each heat pump 10 (step S5) and finishes the process. On the other hand, if the result in step S4 is NO, the control unit 90 determines, similar to step S2, whether the first flow rate F1 is equal to or greater than a predetermined flow rate (step S6). If the result in step S6 is NO, the control unit stops each heat pump 10, assuming that the exhaust heat from the process cooling water E1 is insufficient for balanced cooling and heating operation in each heat pump 10 due to reasons such as being close to stopping the production process (step S5). The control unit 90 immediately stops each heat pump 10 when the first flow rate F1 of the process cooling water E1 falls below a predetermined threshold.

[0025] On the other hand, if the answer in step S6 is YES, the control unit 90 determines whether the sum of the chilled water output (i.e., chilled water output) of each heat pump 10 exceeds a predetermined level, as shown in Figure 2 (step S7). More specifically, the control unit 90 determines whether the sum of the chilled water output of each heat pump 10 (i.e., total chilled water output) plus a predetermined margin (here, 20 kW (kilowatts)) exceeds the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2. Note that various units, including kW, can be changed as appropriate. Also, the predetermined margin value may be something other than 20 kW, or it may not be considered at all. The total chilled water output (kW) is calculated from the first temperature T1 (°C), the second temperature T2 (°C), the total chilled water flow rate (L / h (liters per hour)) which is the flow rate of chilled water flowing through pipe 80, and the chilled water coefficient (kcal / kW) using the following formula (1). The total chilled water flow rate is 20425 L / h in this case. The chilled water coefficient is the amount of heat (kcal (kilocalories)) per kW that chilled water possesses as a cooling medium, and is 860 kcal / kW in this case. The total chilled water flow rate may also be determined by multiplying the flow rate of the pre-adjusted chilled water pump 27 by the number of pumps 27, or by measuring it with a flow meter interposed in the chilled water pipe 60. Furthermore, the total chilled water output may also be calculated from at least one of the rotational speed, load factor, chilled water supply temperature, and hot water supply temperature of each heat pump 10. Total chilled water output = (T2 - T1) × Total chilled water flow rate / Chilled water coefficient (1) The heat energy (kW) of the process cooling water E1 is calculated from the first flow rate F1 (L / h), the 11th temperature T11 (°C), the 12th temperature T12 (°C), and the chilling water coefficient (kcal / kW) using the following equation (2). The heat energy of the process cooling water E1 = (T12 - T11) × F1 / cooling water coefficient (2) The heat energy (kW) of the waste hot water E2 is calculated from the second flow rate F2 (L / h), the 21st temperature T21 (°C), the 22nd temperature T22 (°C), and the chilling coefficient (kcal / kW) using the following equation (3). Heat energy of waste hot water E2 = (T22 - T21) × F2 / chilling coefficient (3)

[0026] If the answer in step S7 is NO, the control unit 90 increases the maximum load limit of each heat pump 10 (step S8). The control unit 90 sets the maximum load limit of each heat pump 10 to the value obtained by adding a predetermined increase to the average rotational speed of each heat pump 10 currently in operation. The predetermined increase is calculated by dividing the difference in heat output chilled water output, which is the value related to the difference in the heat amount of the heat medium E that exceeds the chilled water output when the answer in step S7 is NO, by the number of operating heat pumps 10, and then multiplying by a predetermined rotational speed unit increment value (here, 25 rpm). The amount of heat output is the sum of the heat amount of the heat medium E, i.e., the heat amount of the process cooling water E1 and the heat amount of the waste hot water E2. The difference in heat output chilled water output is obtained by subtracting the total chilled water output from the sum of the heat amount of the process cooling water E1 and the heat amount of the waste hot water E2, and then subtracting a predetermined margin value (here, 20 kW). Furthermore, in the difference value between heat dissipation and chilled water output, the margin does not need to be considered, and a different margin size than that used in step S7 may be used. In other words, when the amount of heat exhausted exceeds a predetermined threshold, the control unit 90 increases the maximum load limit value in each heat pump 10, thereby increasing the load factor and raising the temperature of the hot water supplied to the heat exchanger 32. The 12th temperature T12 of the process cooling water E1, which corresponds to the inlet temperature of the first heat exchanger 61, decreases more sensitively to the decrease in the heat content of the process cooling water E1 than the 11th temperature T11 of the process cooling water E1, which corresponds to the outlet temperature of the first heat exchanger 61. This is because it takes time for the heat from the process cooling water E1 to be absorbed by the chilled water in the first heat exchanger 61. Therefore, by using the 12th temperature T12 in equation (2), the control unit 90 can quickly control the output of each heat pump 10 to match the decrease in the heat content of the process cooling water E1. Furthermore, by using the 12th temperature T12, the control unit 90 can control the output of each heat pump 10 more quickly and appropriately than when using the 3rd temperature T3 and 1st temperature T1 related to chilled water, where there is a time lag in heat exchange with temperature changes. Then, the control unit 90 returns to step S4 and continues processing.

[0027] For example, in step S8, if the average rotational speed of each heat pump 10 is 2974 rpm, the heat output of the process cooling water E1 is 250 kW, the heat output of the waste hot water E2 is 150 kW, and the total chilled water output is 332.6 kW, and there are 2 heat pumps 10 in operation, then 2974 + (250 + 150 - 332.6 - 20) / 2 × 25 = 3566.5, and the maximum load limit of each heat pump 10 is increased to 3566.5 rpm. Furthermore, the rotational speed of 2974 rpm for each heat pump 10 corresponds to a load factor of 70%. Also, the rotational speed of 3566.5 rpm for each heat pump 10 corresponds to a load factor of 80.4%.

[0028] On the other hand, if the answer in step S7 is YES, the control unit 90 processes loop 1 to reduce the output of each heat pump 10. In other words, in step S9, the control unit 90 sets the maximum load limit value for each heat pump 10 to a value obtained by subtracting a predetermined reduction from the average rotational speed of each heat pump 10 currently in operation. The predetermined reduction is calculated by dividing the chilled water output heat output difference value, which is the value related to the difference in chilled water output that exceeds the heat output when the answer is YES in step S7, by the number of operating heat pumps 10, and then multiplying it by a predetermined rotational speed unit reduction value (here, 25 rpm). The chilled water output heat output difference value is obtained by subtracting the heat amount of process cooling water E1 and then subtracting the heat amount of waste hot water E2 from the total chilled water output plus a predetermined margin (here, 20 kW). Note that the margin does not have to be considered in the chilled water output heat output difference value, or a different margin size than in other steps may be used. Then, the control unit 90 moves to step S10 and, similar to step S7, determines the relationship between the total chilled water output and the amount of heat dissipated. If the total chilled water output, including a margin, is greater than the amount of heat dissipated (YES in step S10), the control unit 90 returns to step S9 and repeats loop 1. On the other hand, if the total chilled water output, including a margin, is less than or equal to the amount of heat dissipated (NO in step S10), the control unit 90 uses a timer to determine when a predetermined time (3 minutes in this case) has elapsed (YES in step S11), exits loop 1, and returns to step S4. Before the predetermined time has elapsed (NO in step S11), the control unit 90 repeats the processing of loop 1 to suppress abrupt changes in the control state.

[0029] For example, in step S9, if the average rotational speed of each heat pump 10 is 2974 rpm, the heat output of the process cooling water E1 is 150 kW, the heat output of the waste hot water E2 is 100 kW, and the total chilled water output is 332.6 kW, and there are 2 heat pumps 10 in operation, then 2974 + (332.6 + 20 - 150 - 100) / 2 × 25 = 1691.5, and the maximum load limit of each heat pump 10 is reduced to 1691.5 rpm.

[0030] The heat recovery device 1 described above includes one or more (three) heat pumps that supply hot water to the hot water circuit and receive it from the hot water circuit, and supply chilled water to the chilled water circuit and receive it from the chilled water circuit, and a control unit 90 that controls the hot water and chilled water. The chilled water is heated by a heat-exhaust fluid E, which is a medium that has waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meters 65, 73, temperature sensors 66, 74) that detects the amount of heat in the heat-exhaust fluid E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls at least one of the heat-exhaust fluid, hot water, and chilled water. Therefore, when the heat quantity of the heat medium E changes, the control unit 90 can control the heat pump 10 to prevent it from stopping, for example, by quickly reducing the output when the heat quantity of the heat medium E decreases, thereby reducing the cooling of the chilled water to suppress the temperature drop of the chilled water. This control unit 90 can control the heat pump 10 to prevent it from stopping, for at least one of the heat medium, chilled water, and hot water. In the heat pump type steam generator of Patent Document 1, the heat quantity of the chilled water is detected, and the flow rate of at least one of the chilled water and refrigerant is controlled based on the change in the heat quantity of the chilled water. Therefore, it may not be able to cope with a sudden change in exhaust heat, and the device may stop. In contrast, in the exhaust heat recovery device 1, each heat pump 10 is controlled based on the heat quantity of the heat medium E. Therefore, even if exhaust heat is recovered from an exhaust heat medium E such as relatively unstable exhaust hot water E2, the operation of the heat pump 10 continues. In other words, the waste heat recovery device 1 can recover waste heat, even if it is unstable, while suppressing the occurrence of shutdowns and failures of each heat pump 10, and utilize it for more efficient heating, etc. Furthermore, the waste heat recovery device 1 can recover waste heat even under severe conditions where its heat content changes significantly, and utilize it for more efficient heating, etc.

[0031] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge. Furthermore, the chilled water is first heated by process cooling water E1, which has the average temperature of the heat distribution medium E closest to the chilled water temperature of the heat pump 10, before being heated by the waste hot water E2. Therefore, it becomes possible to heat the chilled water with process cooling water E1 in a way that is more in harmony with the chilled water, and it becomes easier to continue operating each heat pump 10 for recovering waste heat.

[0032] Furthermore, the chilled water circuit includes a first waste heat exchanger 61 that performs heat exchange between chilled water and process cooling water E1, and a second waste heat exchanger 70 that performs heat exchange between chilled water and waste hot water E2. Therefore, heating of the chilled water for waste heat recovery can be performed more appropriately and easily.

[0033] Furthermore, the heat dissipation detection unit consists of flow meters 65 and 73, and temperature sensors 66 and 74. Therefore, the amount of heat in the heat dissipation medium E can be detected more easily. Furthermore, the control unit 90 controls the output and number of operating units of each heat pump 10 according to the amount of heat detected by the heat exhaust detection unit. Therefore, if the amount of heat in the heat exhaust medium E increases rapidly, the output and number of operating units of each heat pump 10 can be reduced, and if the amount of heat in the heat exhaust medium E decreases rapidly, the output and number of operating units of each heat pump 10 can be increased. Consequently, it becomes easier to continue operating each heat pump 10 to continuously recover exhaust heat.

[0034] In addition, the waste heat recovery device 1 includes one or more (three) heat pumps 10 that supply hot water to the hot water side circuit and receive it from the hot water side circuit, and supply chilled water to the chilled water side circuit and receive it from the chilled water side circuit, and a control unit 90 that controls the hot water and chilled water. The chilled water is heated by a waste heat medium E, which is a medium that has waste heat. The chilled water side circuit has a first waste heat heat exchanger 61 that performs heat exchange between chilled water and process cooling water E1, and a second waste heat heat exchanger 70 that performs heat exchange between chilled water and waste hot water E2. The control unit 90 is connected to a chilled water temperature detection unit that detects the temperature of the chilled water. Based on the chilled water temperature detected by the chilled water temperature detection unit, the control unit 90 controls at least one of the output and the number of operating heat pumps 10. Therefore, when the amount of heat in the heat dissipation medium E changes, the control unit 90 can, based on the change in the temperature of the heat dissipation medium E, which changes faster than the temperature of the chilled water that is heat-exchanged with the heat dissipation medium E, or the amount of heat in the hot water required to supply the heat to the chilled water, control the system to suppress the stopping of each heat pump 10, for example, by quickly reducing the output or the number of operating heat pumps 10 when the amount of heat in the heat dissipation medium E decreases, thereby reducing the cooling power of the chilled water to suppress the decrease in the temperature of the chilled water. In other words, the waste heat recovery device 1 can recover waste heat, even if it is unstable, by controlling at least one of the number of operating units and output of each heat pump 10 based on the temperature of the chilled water that exchanges heat with the waste heat or the temperature of the hot water that may change in accordance with the chilled water temperature, thereby suppressing the occurrence of shutdowns and failures of each heat pump 10, and making it possible to use it for more efficient heating, etc. Furthermore, the waste heat recovery device 1 can recover waste heat even under severe conditions in which its heat amount changes significantly, and make it possible to use it for more efficient heating, etc.

[0035] Furthermore, the control unit 90 adjusts the heating output of each heat pump 10 by adjusting the amount of heat from the hot water circuit. Therefore, the waste heat recovery device 1 makes it easier and more appropriate to adjust the heating output of each heat pump 10.

[0036] [Second form] Figure 4 is a schematic diagram of the waste heat recovery device 101 according to the second embodiment, and the waste heat recovery device 101 is the same as the first embodiment except for the configuration relating to the waste heat medium E. In the waste heat recovery device 101, components, parts, processes, etc. that are the same as in the first embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0037] Regarding the heat dissipation medium E, a pipe 102 is provided through which the main flow of process cooling water E1 passes, pipe 63 is provided as a branch pipe and branch flow pipe of pipe 102, and pipe 64 is provided to pass the return flow to pipe 102. Pipe 102 has a temperature sensor 104 and a flow meter 105. The temperature sensor 104 detects the 13th temperature T13, which is the temperature of the process cooling water E1 before branching in pipe 102. The flow meter 105 measures the 3rd flow rate F3, which is the flow rate of the process cooling water E1 before branching in pipe 102. Pipe 63 has a pump 106 as a heat exhaust medium pump instead of a flow meter 65. The flow meter 65 is interposed in pipe 64. Pump 106 can adjust the flow rate of process cooling water E1 to the first heat exhaust heat exchanger 61 and can adjust the amount of heat supplied to the first heat exhaust heat exchanger 61 by the process cooling water E1.

[0038] Similarly, a pipe 112 is provided to carry the main flow of waste hot water E2, pipe 71 is provided as a branch pipe and branch flow pipe of pipe 112, and pipe 72 is provided to carry the return flow to pipe 112. Pipe 71 has a pump 116 as a heat exhaust medium pump instead of a flow meter 73. The flow meter 73 is interposed in pipe 72. Pump 116 can adjust the flow rate of waste hot water E2 to the second heat exhaust heat exchanger 70 and can adjust the amount of heat supplied to the second heat exhaust heat exchanger 70 from the waste hot water E2. Furthermore, at least one of a temperature sensor and a flow meter related to the waste hot water E2 before branching may be installed in pipe 112.

[0039] An example of the operation of such a waste heat recovery device 101 will be described next. Figures 5 and 6 are flowcharts relating to the example of this operation.

[0040] After the control unit 90 makes a decision regarding the operation command for the heat pump 10 (YES in step S1), it determines that the flow rate of the process cooling water E1 before branching, i.e., the third flow rate F3, is 21 m³. 3If the above conditions are met, it is determined whether the temperature of the process cooling water E1 before branching, i.e., the 13th temperature T13, is above a predetermined temperature (in this case, 20°C) (step S102). If the answer is YES, the hot water-based operation of each heat pump 10 is started (step S3). In step S102, it is determined that the factory process, which is the source of the process cooling water E1, is relatively stable, and that the heat from the process cooling water E1 can maintain the balance of each heat pump 10. Next, after the control unit 90 makes a decision regarding the command to stop the heat pump 10 (NO in step S4), the third flow rate F3 is 21m 3 If the above conditions are met, it is determined whether the 13th temperature T13 is above a specific temperature (here, 15°C) that is lower than a predetermined temperature (step S106). If the 3rd flow rate F3 and the 13th temperature T13 are sufficient (YES), the relationship between the total chilled water output and the amount of heat discharged from each heat pump 10 is determined (step S7). In step S106, for example, it is determined whether the load factor per heat pump 10 exceeds 30% and whether the 3rd flow rate F3 and the 13th temperature T13 are sufficient to cover the cooling capacity of 71.3 kW per unit. Here, in order to raise the temperature of the chilled water from a first temperature T1 of 7°C to a third temperature T3 of 10°C by the first heat exchanger 61, a twelfth temperature T12 of 15°C or higher is required in the process cooling water E1 supplied to the first heat exchanger 61, which is 5°C or more above the third temperature T3. The third flow rate F3 of the process cooling water E1 is 20 m³, given the cooling capacity of the heat pump 10 at 71.3 kW. 3 Approximately / h or more is required. 20m at 15℃ 3 The heat energy of the process cooling water E1 at / h is equivalent to a flow rate calculated as 71.3 × 860 × 30%, given that a 3°C temperature increase in chilled water is required (10⁻⁷=3) and the chilled water coefficient is 860 kcal / kW. The heat quantity (kW) of the process cooling water E1 may be calculated using the above formula (2), or it may be calculated using the following formula (4) relating to the total chilled water flow rate (L / h), the first temperature T1 (°C), the third temperature T3 (°C), and the chilled water coefficient (kcal / kW). The total chilled water flow rate is obtained by multiplying the number of operating chilled water pumps 27 by a predetermined value (here, 20425 (L / h)). Heat quantity of process cooling water E1 = (T3 - T1) × total chilled water flow rate / chilled water coefficient (4) The heat energy (kW) of the waste hot water E2 may be calculated using the above formula (3), or it may be calculated using the following formula (5) relating to the total chilled water flow rate (L / h), the third temperature T3 (°C), the fourth temperature T4 (°C), and the chilled water coefficient (kcal / kW). Heat energy of waste hot water E2 = (T4 - T3) × total chilled water flow rate / chilled water coefficient (5)

[0041] If the answer in step S7 is NO, the control unit 90 increases the maximum load limit of each heat pump 10 (step S8). For example, in step S8 of the second form, if the average rotational speed of each heat pump 10 is 3554 rpm (corresponding to a load factor of 80%), and the heat output of the process cooling water E1 is 150 kW, the heat output of the waste hot water E2 is 100 kW, and the total chilled water output is 190 kW, and there is one unit of each heat pump 10 in operation, then 3554 + (150 + 100 - 190 - 20) / 1 × 25 = 4554, and the maximum load limit of each heat pump 10 is increased to 4554 rpm.

[0042] Next, the control unit 90 proceeds to step S120 and determines whether the rotational speed of each operating heat pump 10 exceeds a predetermined value (in this case, 3839 rpm). A rotational speed of 3839 rpm in the heat pump 10 corresponds to a load factor of 85%. Therefore, the determination in step S120 corresponds to determining whether the load factor of each operating heat pump 10 exceeds 85%.

[0043] If the control unit 90 is NO in step S120, it returns to step S4. On the other hand, if the control unit 90 determines YES in step S120, it starts operating one of the stopped heat pumps 10, increasing the number of operating heat pumps 10 by one (step S121). For example, if the control unit 90 determined that there was one operating heat pump 10 at the time of the determination in step S120, it sets the number of operating heat pumps to two in step S121. Then, the control unit 90 sets a maximum load limit value so that the upper limit of the cooling capacity per unit of each heat pump 10 is a value that takes into account the amount of waste heat and the number of heat pumps 10 in operation (step S122). This value is obtained by subtracting the total chilled water output from the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2, then subtracting a margin, dividing the result by the number of heat pumps 10 in operation, and then multiplying it by the rotational speed unit increment value. Step S122 adjusts the maximum load limit value in accordance with the change in the number of heat pumps 10 in operation. After that, the control unit 90 returns to step S4.

[0044] For example, in step S122, if the average rotational speed of each heat pump 10 is 594 rpm (corresponding to a load factor of 30%), and the heat output of the process cooling water E1 is 150 kW, and the heat output of the waste hot water E2 is 100 kW, and there are two heat pumps 10 in operation, the total chilled water output is 71.3 (kW / unit) × 2 (units) = 142.6 kW, then 594 + (150 + 100 - 142.6 - 20) / 2 × 25 = 1686.5, and the maximum load limit of each heat pump 10 is adjusted to 1686.5 rpm (corresponding to a load factor of 58.6%).

[0045] On the other hand, if the result in step S7 is YES, the control unit 90 performs the processing of loop 2. In loop 2, the control unit 90 sets the maximum load limit of each heat pump 10 to a value obtained by subtracting a predetermined reduction from the average rotational speed of each heat pump 10 currently in operation (step S9). For example, in step S9 of the second form, if the average rotational speed of each heat pump 10 is 2974 rpm (equivalent to a load factor of 70%), the heat output of the process cooling water E1 is 100 kW, the heat output of the waste hot water E2 is 50 kW, and the total chilled water output is 332.6 kW, and there are 2 heat pumps 10 in operation, then 2974 - (332.6 + 20 - 100 - 50) / 2 × 25 = 441.5, and the maximum load limit of each heat pump 10 is set to 441.5 rpm (equivalent to a load factor of 27.4%).

[0046] Next, the control unit 90 proceeds to step S123 and determines whether the rotational speed of each operating heat pump 10 is less than a predetermined value (in this case, 594 rpm). A rotational speed of 594 rpm in the heat pump 10 corresponds to a load factor of 30%. Therefore, the determination in step S123 corresponds to determining whether the load factor of each operating heat pump 10 is less than 30%. If the control unit 90 is NO in step S123, it proceeds to step S10.

[0047] On the other hand, if the result in step S123 is YES, the control unit 90 reduces the number of operating heat pumps 10 by 1 (step S124). For example, if the number of operating heat pumps 10 was 2 at the time of the determination in step S123, the control unit 90 reduces the number of operating heat pumps to 1 in step S121. Next, the control unit 90 sets a maximum load limit value so that the upper limit of the cooling capacity per unit in each heat pump 10 is a value that takes into account the amount of waste heat and the number of heat pumps 10 in operation (step S125). This value is obtained by subtracting the total chilled water output from the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2, then subtracting a margin, dividing the result by the number of heat pumps 10 in operation, and multiplying by the rotational speed unit reduction value. Step S125 adjusts the maximum load limit value in accordance with the change in the number of heat pumps 10 in operation. Next, the control unit 90 executes step S10, which involves determining the relative magnitudes of the total chilled water output and the amount of heat dissipated. If the answer is YES, it returns to the beginning of loop 2 (step S9). If the answer is NO, it returns to step S10 before the predetermined waiting time has elapsed (NO in step S11), and after the time has elapsed (YES in step S11), it exits loop 2 and returns to step S4.

[0048] For example, in step S125, if the average rotational speed of each heat pump 10 is 594 rpm (corresponding to a load factor of 30%), and the heat output of the process cooling water E1 is 100 kW, and the heat output of the waste hot water E2 is 50 kW, and furthermore, if there is one heat pump 10 in operation, the total chilled water output will be 71.3 kW, then 594 + (100 + 50 - 71.3 - 20) / 1 × 25 = 2061.5, and the maximum load limit of each heat pump 10 will be adjusted to 2061.5 rpm (corresponding to a load factor of 64.9%).

[0049] In the heat recovery device 101 described above, chilled water is heated by a heat-exhaust medium E, which is a medium containing waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meters 65, 73, 105, temperature sensors 66, 74) that detects the amount of heat in the heat-exhaust medium E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls at least one of the hot water and chilled water. Therefore, even if the heat content of the heat dissipation medium E changes rapidly, the operation of each heat pump 10 will continue.

[0050] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0051] [Third form] Figure 7 is a schematic diagram of the waste heat recovery device 201 according to the third embodiment, and the waste heat recovery device 201 is the same as the second embodiment except for the configuration relating to the chilled water side. In the waste heat recovery device 201, components, parts, processes, etc. that are the same as in the second embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0052] A three-way valve 202 is installed in the pipe 60 leading to the first heat exchanger 61. A bypass pipe 204 is connected to the three-way valve 202. The bypass pipe 204 is connected to a pipe 80 that returns chilled water to each heat pump 10. The three-way valve 202 adjusts the flow rate of chilled water from the upstream part of pipe 60 to the downstream part and the flow rate to the bypass pipe 204. The three-way valve 202 adjusts the flow rate of chilled water to the first heat exchanger 61, and consequently adjusts the chilled water temperature to the first heat exchanger 61, thereby adjusting the amount of chilled water supplied to the first heat exchanger 61. The control unit 90 can control the opening degree of the three-way valve 202 on the first heat exhaust heat exchanger 61 side (main pipe side opening degree) and the bypass side (branch pipe side opening degree), respectively, from a predetermined lower limit (e.g., 0%) to a predetermined upper limit (e.g., 100%). When the main pipe side opening degree is 100% and the branch pipe side opening degree is 0%, all the chilled water entering the three-way valve 202 flows to the downstream portion of pipe 60. When the main pipe side opening degree is 0% and the branch pipe side opening degree is 100%, all the chilled water entering the three-way valve 202 flows to the bypass pipe 204. The flow rate of chilled water to the first heat exchanger 61 increases according to the degree of opening of the main pipe side of the three-way valve 202. Also, the flow rate of chilled water to the bypass pipe 204 increases according to the degree of opening of the branch pipe side of the three-way valve 202. Furthermore, the control unit 90 may control the opening degree of the main pipe and the opening degree of the branch pipe in the three-way valve 202 in a coordinated manner, for example, by controlling their combined opening to 100%. Also, at least one of the predetermined lower limit and predetermined upper limit of the opening degree of the main pipe in the three-way valve 202 and at least one of the predetermined lower limit and predetermined upper limit of the opening degree of the branch pipe may be the same or different. Adjustment of the opening degree of the main pipe in the three-way valve 202 may be omitted.

[0053] A three-way valve 212 is installed in the pipe 68 leading to the second heat exchanger 70. A bypass pipe 214 is connected to the three-way valve 212. The bypass pipe 214 is connected to a pipe 80 that returns chilled water to each heat pump 10. The three-way valve 212 adjusts the flow rate of chilled water from the upstream part of pipe 68 to the downstream part and the flow rate to the bypass pipe 214. The three-way valve 212 adjusts the flow rate of chilled water to the second heat exchanger 70, and consequently adjusts the chilled water temperature to the second heat exchanger 70, thereby adjusting the amount of chilled water supplied to the second heat exchanger 70. The control unit 90 can control the opening degree of the three-way valve 212 on the second heat exhaust heat exchanger 70 side (main pipe side opening degree) and the bypass side (branch pipe side opening degree), respectively, from a predetermined lower limit to a predetermined upper limit. When the main pipe side opening degree is 100% and the branch pipe side opening degree is 0%, all the chilled water entering the three-way valve 212 flows to the downstream portion of pipe 68. When the main pipe side opening degree is 0% and the branch pipe side opening degree is 100%, all the chilled water entering the three-way valve 212 flows to the bypass pipe 214. The flow rate of chilled water to the second heat exchanger 70 increases according to the degree of opening of the main pipe side of the three-way valve 212. Also, the flow rate of chilled water to the bypass pipe 214 increases according to the degree of opening of the branch pipe side of the three-way valve 212. Furthermore, the control unit 90 may control the opening degree on the main pipe side and the opening degree on the branch pipe side of the three-way valve 212 in a linked manner. Also, at least one of the predetermined lower limit and predetermined upper limit of the opening degree on the main pipe side of the three-way valve 212 and at least one of the predetermined lower limit and predetermined upper limit of the opening degree on the branch pipe side may be the same or different. At least one of the predetermined lower limit and predetermined upper limit of each opening degree in the three-way valve 212 may be the same as or different from that of the three-way valve 202. Adjustment of the opening degree on the main pipe side of the three-way valve 212 may be omitted. At least one of the three-way valves 202 and 212 may be omitted.

[0054] An example of the operation of such a waste heat recovery device 201 will be described next. Figures 8 and 9 are flowcharts relating to the example of this operation.

[0055] The control unit 90 processes steps S1, S102, S3, S4, S5, and S106 in the same manner as in the second embodiment. If the answer in step S106 is YES, the control unit 90 proceeds to step S201 to determine the increase in the amount of heat in the process cooling water E1 per predetermined unit time (in this case, 1 minute). More specifically, the control unit 90 determines whether the amount of heat in the process cooling water E1 per minute (kW / min) exceeds the value obtained by dividing the total chilled water output (kW) of the currently operating heat pump 10 by the chilled water inlet / outlet temperature difference per minute. The chilled water inlet / outlet temperature difference is the value obtained by subtracting the first temperature T1 (assumed to be 20°C) from the second temperature T2 (assumed to be 30°C), which is 10°C in this case. Each heat pump 10 and the chilled water flow rate are selected so that the chilled water inlet / outlet temperature difference is 10°C for each heat pump 10 operating at a load factor of 100%. Step S201 evaluates the effect of changes in the heat content of the process cooling water E1 on the total chilled water output of the currently operating heat pump 10. For example, if the total chilled water output is small, even if the change in the heat content of the process cooling water E1 is small, the operation of each heat pump 10 cannot keep up with the change. In other words, the value obtained by dividing the total chilled water output (kW) of the currently operating heat pump 10 per minute by the chilled water inlet / outlet temperature difference design value indicates the limit on the rate of temperature change per minute and per 1°C chilled water inlet / outlet temperature difference.

[0056] If the response in step S201 is YES and the change in the heat quantity of the process cooling water E1 per minute is rising above the above value and exceeds the temperature change rate limit, the control unit 90 proceeds to step S202 and increases the opening of the branch pipe side of the three-way valve 202 from 0% to a predetermined value (20% in this case). The control unit 90 quickly grasps the change in the heat quantity of the process cooling water E1 by detecting the third flow rate F3 and the 13th temperature T13, and if it exceeds the temperature change rate limit, it immediately increases the opening of the branch pipe side of the three-way valve 202. As a result, a route for chilled water is formed that bypasses the first exhaust heat exchanger 61 which exchanges heat between the rapidly rising process cooling water E1 and chilled water, and a rapid rise in the temperature of the second temperature T2 of the chilled water returning to each heat pump 10 is suppressed. If the control unit 90 is NO in step S201, and the amount of heat in the process cooling water E1 per minute has not risen above the above value and is below the temperature change rate limit, it skips step S202 and proceeds to step S203.

[0057] In step S203, the control unit 90 determines the increase in the heat content of the waste hot water E2 per predetermined unit time (here, 1 minute). More specifically, the control unit 90 determines whether the rate of change in the temperature of the waste hot water E2 every minute (°C / min) is rising above a predetermined value (here, 1°C / min). Note that the predetermined unit time in step S203 may be different from the predetermined unit time in step S201. If the response in step S203 is YES and the temperature of the wastewater E2 per minute is rising by 1°C / minute or more, the control unit 90 proceeds to step S204, where it decreases the opening of the main pipe side of the three-way valve 212 from a predetermined value (20% in this case) to a specific value (10% in this case), and then proceeds to step S205, where it increases the opening of the branch pipe side from a predetermined value (0% in this case) to a specific value (15% in this case), and then proceeds to step S7. If the control unit 90 is NO in step S203 and the amount of heat in the waste hot water E2 per minute has not risen above a predetermined level, it skips steps S204 and S205 and proceeds to step S7.

[0058] Step S203 evaluates the effect of changes in the heat content of the waste hot water E2. For example, if the temperature of the waste hot water E2 rises from 40°C to 70°C in 1 minute in a range of 30°C, the 22nd temperature T22 of the waste hot water E2 to the second waste heat exchanger 70 rises, and the 4th temperature T4 of the chilled water after passing through the second waste heat exchanger 70 also rises. If the three-way valve 212 is not provided, the output of the pump 116 will be reduced in response to the rise in the fourth temperature T4, but this will not be fast enough. The second temperature T2 of the chilled water returning to each heat pump 10 will rise sharply, exceeding the chilled water return temperature rise limit (in this case, 1°C / min), which will lead to the shutdown of each heat pump 10. In general, various temperature sensors, including thermocouples, have a detection delay of several seconds or more. Even if a temperature sensor detects a rapid rise in the temperature of the chilled water, the temperature has actually already risen several seconds prior. Therefore, even if control is attempted to avoid shutting down each heat pump 10 after detecting a rapid rise in the fourth temperature T4 of the chilled water, it may not be fast enough. In the waste heat recovery device 201, the control unit 90 uses the temperature of the waste hot water E2, which changes temperature at an earlier stage than the temperature change of the chilled water, to detect an early temperature rise in the waste hot water E2 that could lead to a limit on the rise in the chilled water return temperature (step S203). In advance, it reduces the flow rate of chilled water to the second waste heat exchanger 70 by narrowing the opening of the main pipe side of the three-way valve 212 (step S204), or increases the opening of the branch pipe side of the three-way valve 212 to suppress the temperature rise of the chilled water returning to each heat pump 10 (step S205). This prevents the shutdown of each heat pump 10 due to a sudden rise in chilled water temperature, and allows each heat pump 10 to continue operating even if there is a sudden rise in the temperature of the waste hot water E2.

[0059] From step S7 onward, the control unit 90 operates in the same manner as in the second embodiment.

[0060] In the heat recovery device 201 described above, chilled water is heated by a heat-exhaust medium E, which is a medium containing waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meters 65, 73, 105, temperature sensors 66, 74) that detects the amount of heat in the heat-exhaust medium E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls at least one of the hot water and chilled water. Furthermore, the heat recovery device 201 is equipped with a three-way valve 202 that adjusts the amount of chilled water supplied to the first heat exchanger 61 for waste heat, and a three-way valve 212 that adjusts the amount of chilled water supplied to the second heat exchanger 70 for waste heat. Therefore, even if the amount of heat of the exhaust heat medium E changes rapidly, the heating amount of the cooling water by the exhaust heat medium E is adjusted by the three-way valves 202 and 212 based on the amount of heat detected by the exhaust heat amount detection unit, and the operation of each heat pump 10 continues.

[0061] In addition, there are multiple types of exhaust heat medium E, namely process cooling water E1 and exhaust warm water E2. Therefore, with different combinations of the types of exhaust heat medium E, the exhaust heat medium E as the recovery target becomes more stable as a whole, and the operation of each heat pump 10 for recovering exhaust heat becomes easier to continue. Furthermore, the exhaust heat of the process cooling water E1, which is one of the exhaust heat media E, is stable. Therefore, the operation of each heat pump 10 for recovering exhaust heat becomes easier to continue.

[0062] [Fourth Embodiment] FIG. 10 is a schematic diagram of an exhaust heat recovery device 301 according to the fourth embodiment. The exhaust heat recovery device 301 is the same as the first embodiment except for the configuration related to the number of heat pumps 10. For members, parts, processes, etc. that are the same as those in the first embodiment in the exhaust heat recovery device 301, the same reference numerals are appropriately assigned and the description is omitted.

[0063] The number of heat pumps 10 in the exhaust heat recovery device 301 is one. The total cooling water output of each heat pump 10 in the first embodiment is equivalent to the cooling water output of the heat pump 10 in the fourth embodiment related to one heat pump 10.

[0064] An operation example of such an exhaust heat recovery device 301 will be described next. FIGS. 11 and 12 are flowcharts related to the operation example.

[0065] The control unit 90 processes in the same manner as in the first embodiment until steps S1 to S6. However, the threshold value of the flow rate of the process cooling water E1 in steps S2 and S6 is 20 m 3 instead of 21 m 3 and is thus.

[0066] After step S6, the control unit 90 proceeds to step S301 and determines whether the chilled water output of the heat pump 10 is greater than the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2. If the answer in step S301 is YES, the control unit 90 executes loop 3 to reduce the output of the heat pump 10.

[0067] In loop 3, the control unit 90 determines the magnitude of the chilled water output of the heat pump 10 and the heat quantity of the heat dissipation medium E, similar to step S301 (step S302). If the response in step S302 is YES and the chilled water output exceeds the heat output of the heat dissipation medium E, the control unit 90 sets the maximum load limit of the heat pump 10 to a value that is gradually reduced from the current rotational speed (step S303). Here, the control unit 90 reduces the rotational speed from the current speed by a predetermined amount (590 rpm) every predetermined unit time (1 minute). 590 rpm / min corresponds to a load factor of 10%, which corresponds to a 1°C increase in the chilled water outlet temperature of the heat pump 10 per minute. After that, the control unit 90 returns to the beginning of loop 3 (step S302).

[0068] On the other hand, if the control unit 90 is NO in step S302, it proceeds to step S304 and performs a timer check in the same way as in step S11. If it is NO before the predetermined time (in this case, 3 minutes) has elapsed, it returns to step S302, and if it is YES after the predetermined time has elapsed, it exits loop 3 and returns to step S4.

[0069] On the other hand, if the control unit 90 is NO in step S301 and the chilled water output is less than or equal to the heat quantity of the heat dissipation medium E, it proceeds to step S311 to determine the relationship between the chilled water output and the heat quantity of the heat dissipation medium E, taking into account a first margin (in this case, 30 kW). That is, the control unit 90 determines whether the value obtained by adding the first margin to the chilled water output is less than the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2. If the answer in step S311 is NO, the control unit 90 skips loop 4 for increasing the maximum load limit of the heat pump 10 and returns to step S4; if the answer in step S311 is YES, it executes loop 4.

[0070] In loop 4, the control unit 90 determines the relationship between the chilled water output, taking into account a second margin (20 kW in this case) that is less than or equal to the first margin, and the heat quantity of the waste heat medium E (step S312). That is, the control unit 90 determines whether the value obtained by adding the second margin to the chilled water output is less than the sum of the heat quantity of the process cooling water E1 and the heat quantity of the waste hot water E2. If the answer in step S312 is NO, the control unit 90 skips step S313 and returns to step S4, and if the answer in step S312 is YES, it executes step S313. If the response in step S312 is YES and the chilled water output, including the second margin, is less than the heat output of the heat dissipation medium E, the control unit 90 sets the maximum load limit of the heat pump 10 to a value that is gradually increased from the current rotational speed (step S313). Here, the control unit 90 sets the maximum load limit of the heat pump 10 to a value that is increased by a predetermined amount (590 rpm) for every predetermined unit time (1 minute) that has elapsed from the current rotational speed. After that, the control unit 90 returns to the beginning of loop 3 (step S312).

[0071] In step S312, for example, if the control unit 90 increases the maximum load limit, the heat pump 10 increases its rotational speed to bring the hot water outlet temperature to the set value of 80°C, and the chilled water output and hot water output of the heat pump 10 increase. If the answer in step S312 is NO, the control unit 90 will not increase the maximum load limit because increasing the output of the heat pump 10 any further would cause the chilled water outlet temperature of the heat pump 10 to drop more than necessary. Furthermore, if the answer in step S312 is YES, the control unit 90 increases the maximum load limit. However, once the hot water outlet temperature of the heat pump 10 recovers to 80°C, the rotational speed of the heat pump 10 does not increase due to the hot water-based operation, and the output of the heat pump 10 does not increase, so the maximum load limit becomes 100% (equivalent to a rotational speed of 4724 rpm).

[0072] In the heat recovery system 301 described above, there is one heat pump 10, and the chilled water is heated by a heat-exhaust medium E, which is a medium containing waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meters 65, 73, temperature sensors 66, 74) that detects the amount of heat in the heat-exhaust medium E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls the heat pump 10 according to its maximum load limit. Therefore, even if the heat content of the heat dissipation medium E changes rapidly, the operation of each heat pump 10 will continue.

[0073] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0074] [Fifth form] Figure 13 is a schematic diagram of the exhaust heat recovery device 401 according to the fifth embodiment, and the exhaust heat recovery device 401 is the same as the first embodiment except for the configuration relating to a part of the hot water side and a part of the chilled water side. In the waste heat recovery device 401, components, parts, processes, etc. that are the same as in the first embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0075] In the waste heat recovery system 401, there are four heat pumps 10. A pump 423, similar to pump 23, is installed in the pipe 33 leading to the heat exchanger 32 through which the hot water from each heat pump 10 passes. The heating load H includes a first heating load H1 and a second heating load H2. A pipe 442 is provided from the second heating load H2 to the heat exchanger 32, and a pipe 441 is provided from the heat exchanger 32 to the hot water tank 40. The pipe 44 coming out of the hot water tank 40 branches into a pipe 444A to the first heating load H1 and a pipe 444B to the second heating load H2. The steam supply path 47 is connected to pipe 44. A pipe 446 is provided from the second heating load H2 to the hot water tank 40.

[0076] A three-way valve 402 is installed in the main pipe 60 through which chilled water flows from each heat pump 10 to the first waste heat exchanger 61. A bypass pipe 404 (branch pipe) is connected to the three-way valve 402. The bypass pipe 404 is connected to a pipe 80 that returns chilled water to the heat pump 10. The three-way valve 402 operates in the same way as the three-way valves 202 and 212 to adjust the flow rate of chilled water to the first waste heat exchanger 61, and consequently adjusts the chilled water temperature to the first waste heat exchanger 61, thereby adjusting the amount of chilled water supplied to the first waste heat exchanger 61. A chilled water tank 480 is connected to pipe 80. A pipe 426 with a pump 427 is positioned between the chilled water tank 480 and the heat pump 10. Furthermore, sensors and flow meters not shown in Figure 13 can be omitted from the waste heat recovery device 401. Such omissions can also be made in other configurations.

[0077] An example of the operation of such a heat recovery device 401 will be described next.

[0078] For example, the temperature of the hot water in the pipes 33 from each heat pump 10 is assumed to be 90°C. The temperature of the hot water in the pipes 34 returning to each heat pump 10 is assumed to be 82°C. The temperature of the hot water coming out of the first heating load H1 and the temperature of the hot water coming out of the second heating load H2 are both assumed to be 60°C. The temperature of the hot water in the hot water tank 40 is assumed to be 70°C. The temperature of the hot water downstream of the steam supply path 447 in pipe 44 is assumed to be 85°C. Furthermore, the temperature of the chilled water on the main pipe side from each heat pump 10 to the first exhaust heat exchanger 61 is assumed to be 19°C in summer and 9°C in winter, and the temperature of the chilled water coming out of the first exhaust heat exchanger 61 is assumed to be 27°C in summer and 17°C in winter. The temperature of the chilled water on the branch pipe side of the three-way valve 402 is assumed to be 24°C in summer and 17°C in winter. In addition, the temperature of the chilled water to the second exhaust heat exchanger 70 is assumed to be 27°C in summer and 17°C in winter, and the temperature of the chilled water coming out of the second exhaust heat exchanger 70 is assumed to be 65°C in summer and 65°C in winter. The temperature difference between the chilled water inlet and outlet at each heat pump 10 is assumed to be 8°C in summer. In addition, when all heat pumps 10 are in operation, the flow rate of chilled water related to the heat pumps 10 is assumed to be 110,510 L / h, and the flow rate of chilled water in the branch pipes is assumed to be 0 L / h in summer and 96,409 L / h in winter.

[0079] Furthermore, the temperature of the process cooling water E1 entering the first heat exchanger 61 is assumed to be 32°C in summer and 22°C in winter, and the temperature of the process cooling water E1 leaving the first heat exchanger 61 is assumed to be 24°C in summer and 14°C in winter. In addition, the temperature of the waste hot water E2 entering the second waste heat exchanger 70 is expected to fluctuate significantly compared to the temperature of the process cooling water E1, fluctuating between 40 and 70°C, and the temperature of the waste hot water E2 exiting the second waste heat exchanger 70 is expected to be 30°C. The temperature of the waste hot water E2 is expected to be higher than the temperature of the chilled water in the chilled water tank 480, and is expected to compensate for the heat deficiency of the process cooling water E1 and raise the temperature of the chilled water in the chilled water tank 480 even in winter. The heat quantity, flow rate, temperature change range, and temperature change amplitude of the waste hot water E2 are investigated in advance and used to select the capacity of the second waste heat exchanger 70 within a range that does not affect various limitations related to the chilled water temperature of each heat pump 10. The first waste heat exchanger 61 and the second waste heat exchanger 70 only need to be able to handle chilled water flow rates of 110,510 L / h in summer and 14,101 L / h in winter.

[0080] In the waste heat recovery device 401, the temperature of the chilled water in the first waste heat heat exchanger 61 is steadily increased by heat exchange with the chilled water using process cooling water E1, which has a more stable temperature than the waste hot water E2. For example, in summer, the control unit 90 sets the opening of the branch pipe of the three-way valve 402 to 0%, thereby setting the bypass chilled water flow rate to 0 and controlling the temperature increase of the 19°C chilled water entering the first waste heat heat exchanger 61 to 27°C. The temperature of the process cooling water E1 goes from 32°C to 24°C. In winter, the control unit 90 adjusts the opening of the branch pipe of the three-way valve 402 to adjust the bypass chilled water flow rate and controls the temperature increase of the 9°C chilled water entering the first waste heat heat exchanger 61 to 17°C. The temperature of the process cooling water E1 goes from 22°C to 14°C. The control unit 90 adjusts the amount of heat exchange between the chilled water and the heat dissipation medium E by adjusting the flow rate of the bypassed chilled water, and controls the second temperature T2, which is the chilled water return temperature, to fall within a range that suppresses the shutdown of each heat pump 10. Furthermore, in the waste heat recovery device 401, the relatively unstable waste hot water E2 is used to supplementarily raise the temperature of the chilled water. For example, in summer, if the temperature of the waste hot water E2 is at the maximum fluctuation range of 70°C, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat heat exchanger 70. The chilled water passing through the second waste heat heat exchanger 70 is then heated from 27°C to 65°C, merges with the chilled water in the branch pipe, and enters the chilled water tank 480. In winter, if the temperature of the waste hot water E2 is at the maximum fluctuation range of 70°C, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat heat exchanger 70. The chilled water passing through the second waste heat heat exchanger 70 is then heated from 17°C to 65°C, merges with the chilled water in the branch pipe, and enters the chilled water tank 480. The three-way valve 402 controls the flow rate of chilled water passing through the second heat exchanger 70 for exhaust heat to, for example, 110,510 L / h in summer, and the flow rate of chilled water passing through the second heat exchanger 70 for exhaust heat to, for example, 14,101 L / h in winter. The temperature of the chilled water in the chilled water tank 480 is, for example, 32°C in summer and 23.5°C in winter. The control unit 90 controls the opening degree of each three-way valve 402 so that the temperature of the chilled water in the chilled water tank 480 becomes a set value (for example, 32°C in summer and 23.5°C in winter).

[0081] When the control unit 90 detects that at least one of the second temperature T22 and second flow rate F2 of the waste hot water E2 has increased to a predetermined level or higher, it controls the three-way valve 402 to increase the flow rate of chilled water to the branch pipe, reducing the amount of heat exchange between the chilled water and the waste hot water E2, and adjusting so that the second temperature T2 of the chilled water returning to each heat pump 10 reaches the set value. Furthermore, when the control unit 90 detects that at least one of the 22nd temperature T22 and 2nd flow rate F2 of the waste hot water E2 has decreased by a predetermined amount or more, it preemptively reduces the output of each heat pump 10 to suppress a decrease in the 1st temperature T1 of the chilled water coming out of each heat pump 10 and the 2nd temperature T2 of the chilled water returning from each heat pump 10 that would lead to shutdown. The control unit 90 uses the flow meter 73 and temperature sensor 74 to grasp the change in the heat quantity of the waste hot water E2, rather than the change in the heat quantity of the chilled water, and uses this information to control the three-way valve 402 and each heat pump 10. This allows the control unit 90 to quickly grasp the change in the amount of heat the chilled water is heated by heat exchange with the waste hot water E2, thereby suppressing the shutdown of each heat pump 10 and ensuring that each heat pump 10 continues to operate even if the heat quantity of the waste hot water E2 changes rapidly.

[0082] In the heat recovery device 401 described above, chilled water is heated by a heat-exhaust medium E, which is a medium containing waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meter 73, temperature sensor 74) that detects the amount of heat in the heat-exhaust medium E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls at least one of the hot water and chilled water. Furthermore, the heat recovery device 401 has a three-way valve 402 that adjusts the amount of heat in the chilled water. Therefore, even if the heat content of the heat dissipation medium E changes rapidly, the operation of each heat pump 10 will continue.

[0083] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0084] [6th form] Figure 14 is a schematic diagram of the exhaust heat recovery device 501 according to the sixth embodiment, and the exhaust heat recovery device 501 is the same as the fifth embodiment except for the configuration relating to a part of the chilled water side. In the waste heat recovery device 501, components, parts, processes, etc. that are the same as in the fifth embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0085] A three-way valve 502, similar to the three-way valve 402, is interposed in the pipe 68 (main pipe) between the first heat exchanger 61 and the second heat exchanger 70. A bypass pipe 504 (second branch pipe), similar to the bypass pipe 404 (first branch pipe), is provided between the three-way valve 502 and the return chilled water pipe 80.

[0086] An example of the operation of such a heat recovery device 501 will be described next.

[0087] For example, various temperatures on the hot water side are assumed to be the same as in the fifth configuration. Furthermore, the various temperatures on the cold water side are assumed to be the same as in the fifth configuration, except as described below. The flow rate of chilled water in the first branch pipe is assumed to be 0 L / h in summer and 0 L / h in winter. The flow rate of chilled water in the second branch pipe is assumed to be 95,969 L / h in summer and 96,409 L / h in winter. The flow rate of chilled water passing through the second heat exchanger 70 for waste heat is assumed to be 14,541 L / h in summer and 14,101 L / h in winter.

[0088] Furthermore, the temperature of the process cooling water E1 is assumed to be the same as in the fifth embodiment. In addition, the temperature of the wastewater E2 is assumed to be the same as in the fifth configuration.

[0089] In the waste heat recovery device 501, the temperature of the chilled water in the first waste heat heat exchanger 61 is steadily increased by heat exchange with the chilled water using process cooling water E1, which has a more stable temperature than the waste hot water E2. For example, in summer, the control unit 90 sets the opening of the first branch pipe of the three-way valve 402 to 0%, setting the bypass chilled water flow rate to 0, and controls the temperature increase of the 19°C chilled water entering the first waste heat heat exchanger 61 to 27°C. The process cooling water E1 goes from 32°C to 24°C. In winter, the control unit 90 adjusts the bypass chilled water flow rate by adjusting the opening of the branch pipe of the three-way valve 402, and controls the temperature increase of the 9°C chilled water entering the first waste heat heat exchanger 61 to 17°C. The process cooling water E1 goes from 22°C to 14°C. The control unit 90 adjusts the amount of heat exchange between the chilled water and the heat transfer medium E (mainly process cooling water E1) by adjusting the flow rate of chilled water bypassed by the first branch pipe, and controls the second temperature T2, which is the chilled water return temperature, to fall within a range that suppresses the shutdown of each heat pump 10. Furthermore, in the waste heat recovery device 501, the relatively unstable waste hot water E2 is used to supplementarily raise the temperature of the chilled water. For example, in summer, if the temperature of the waste hot water E2 is 70°C, which is the maximum temperature within the fluctuation range, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat exchanger 70. The chilled water passing through the second waste heat exchanger 70 is then heated from 27°C to 65°C, and after merging with the chilled water in each branch pipe, it enters the chilled water tank 480. The control unit 90 adjusts the flow rate of chilled water passing through the second waste heat exchanger 70 to, for example, 14541 L / h by adjusting the flow rate of chilled water bypassed by the second branch pipe (for example, 95969 L / h), thereby adjusting the amount of heat exchange between the chilled water and the waste hot water E2, and controlling the second temperature T2, which is the chilled water return temperature, to stay within a range that suppresses the shutdown of each heat pump 10. Furthermore, in winter, when the temperature of the waste hot water E2 is at the maximum fluctuation range of 70°C, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat exchanger 70. The chilled water passing through the second waste heat exchanger 70 is then heated from 17°C to 65°C, and after merging with the chilled water in each branch pipe, it enters the chilled water tank 480. The three-way valve 502 controls the flow rate of chilled water passing through the second waste heat exchanger 70 in winter to, for example, 14101 L / h. The chilled water flow rate in the second branch pipe is, for example, 96409 L / h. The temperature of the chilled water in the chilled water tank 480 is, for example, 32°C in summer and 23.5°C in winter. The control unit 90 controls the opening degree of each three-way valve 402 so that the temperature of the chilled water in the chilled water tank 480 becomes a set value (for example, 32°C in summer and 23.5°C in winter).

[0090] The control unit 90 monitors the change in the heat quantity of the process cooling water E1 using the first flow rate F1 and the 12th temperature T12, and monitors the change in the heat quantity of the waste hot water E2 using the second flow rate F2 and the 22nd temperature T22. When the control unit 90 detects that the heat content of the process cooling water E1 has increased to a predetermined level or higher, and that the heat content of the waste hot water E2 has increased to a predetermined level or higher, it controls the three-way valves 402 and 502 to increase the flow rate of chilled water to each branch pipe, reduces the amount of heat exchange between the chilled water and the waste heat medium E, and adjusts the second temperature T2 of the chilled water returning to each heat pump 10 to a set value. Furthermore, when the control unit 90 detects that the heat content of the process cooling water E1 has decreased by a predetermined amount or more, and that the heat content of the waste hot water E2 has decreased by a predetermined amount or more, it preemptively reduces the output of each heat pump 10 to suppress a decrease in the first temperature T1 of the chilled water coming out of each heat pump 10 and the second temperature T2 of the chilled water returning from each heat pump 10 that would lead to shutdown. The control unit 90 uses the flow meter 65 and temperature sensor 66 to grasp the change in the heat quantity of the process cooling water E1, rather than the change in the heat quantity of the chilled water, and the flow meter 73 and temperature sensor 74 to grasp the change in the heat quantity of the waste hot water E2, and uses this information to control the three-way valves 402 and 502 and each heat pump 10. This allows for quick detection of changes in the amount of heat the chilled water is heated due to heat exchange with the waste heat medium E, thereby suppressing the shutdown of each heat pump 10, and ensuring that each heat pump 10 continues to operate even if the heat quantity of the waste heat medium E (especially the waste hot water E2) changes rapidly.

[0091] In the heat recovery device 501 described above, chilled water is heated by a heat-exhaust medium E, which is a medium containing waste heat. The control unit 90 is connected to a heat-exhaust amount detection unit (flow meters 65, 73, temperature sensors 66, 74) that detects the amount of heat in the heat-exhaust medium E. Based on the amount of heat detected by the heat-exhaust amount detection unit, the control unit 90 controls at least one of the hot water and chilled water. Furthermore, the heat recovery device 501 has a three-way valve 402 that adjusts the amount of heat exchange between chilled water and process cooling water E1, and a three-way valve 502 that adjusts the amount of heat exchange between chilled water and waste hot water E2. Therefore, even if the heat content of the heat dissipation medium E changes rapidly, the operation of each heat pump 10 will continue.

[0092] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0093] [7th form] Figure 15 is a schematic diagram of the waste heat recovery device 601 according to the seventh embodiment, and the waste heat recovery device 601 is the same as the sixth embodiment except for the configuration relating to a part of the chilled water side. In the waste heat recovery device 601, components, parts, processes, etc. that are the same as those in the sixth embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0094] The heat recovery device 601 consists of the solenoid valves 602, 611-613, replacing the three-way valves 402 and 502 of the sixth form. In other words, a solenoid valve 602 is installed in the bypass pipe 404 (first branch pipe) which branches directly from the main pipe 60. Furthermore, a pipe assembly 610 is combined with pipe 68 (main pipe) and bypass pipe 504 (second branch pipe) which branches directly from pipe 68. The pipe assembly 610 is a ladder-shaped pipe assembly of a predetermined number of stages (three stages including the main pipe) and includes a supplementary pipe 620 that extends in the same direction as the bypass pipe 504, and one or more (two in this case) connecting pipes 622 that are passed between the bypass pipe 504 and the supplementary pipe 620. The branching point of the supplementary pipe 620 from the main pipe is located downstream of the branching point of the bypass pipe 504 from the main pipe. Furthermore, a solenoid valve 611 is installed between the branching point of the bypass pipe 204 and the branching point of the auxiliary pipe 620 in the main pipe. In addition, a solenoid valve 612 is installed in the connecting pipe 622 on the side closer to the main pipe. Moreover, a solenoid valve 613 is installed in the connecting pipe 622 on the side further away from the main pipe. Generally, solenoid valve 602 is less expensive than three-way valve 402. Also, solenoid valves 611-613 are less expensive than three-way valve 502.

[0095] The control unit 90 can control the flow rate of chilled water to the first branch pipe by controlling the solenoid valve 602, similar to the three-way valve 402 of the sixth embodiment. Furthermore, the control unit 90 can control the flow rate of chilled water to the second branch pipe by controlling the solenoid valves 611 to 613, similar to the three-way valve 502 of the sixth embodiment.

[0096] In the waste heat recovery device 601 described above, chilled water is heated by a waste heat medium E, which is a medium containing waste heat. The control unit 90 is connected to a waste heat quantity detection unit (flow meter 73, temperature sensor 74) that detects the amount of heat in the waste heat medium E. Based on the amount of heat detected by the waste heat quantity detection unit, the control unit 90 controls at least one of the hot water and chilled water. Furthermore, the waste heat recovery device 601 has a solenoid valve 602 that adjusts the amount of heat exchange between chilled water and process cooling water E1, and solenoid valves 611 to 613 of the assembled pipe section 610 that adjusts the amount of heat exchange between chilled water and waste hot water E2. Therefore, even if the heat content of the waste hot water E2 changes rapidly, the operation of each heat pump 10 will continue. Moreover, the same chilled water control as with the three-way valves 402, 502, etc. can be performed at a lower cost using the solenoid valves 602, 611-613.

[0097] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0098] [8th form] Figure 16 is a schematic diagram of the exhaust heat recovery device 701 according to the eighth embodiment, and the exhaust heat recovery device 701 is the same as the fifth embodiment except for the configuration relating to a part of the chilled water side. In the waste heat recovery device 701, components, parts, processes, etc. that are the same as those in the fifth embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0099] In the waste heat recovery device 701, the chilled water circuit of the first waste heat exchanger 61 and the chilled water circuit of the second waste heat exchanger 70 are connected only by the chilled water tank 480, and are independent of each other except for the chilled water tank 480. Each heat pump 10 is directly connected to the first exhaust heat exchanger 61, and indirectly connected to the second exhaust heat exchanger 70 via the chilled water tank 480.

[0100] In other words, the chilled water pipe 768 coming out of the first heat exchanger 61 does not connect to the second heat exchanger 70, but connects to the chilled water tank 480. The bypass pipe 404 is connected to pipe 768. The second temperature sensor T2 related to the chilled water return temperature, temperature sensor 82, detects the chilled water temperature in the chilled water tank 480.

[0101] Furthermore, a chilled water pipe 760 is provided from the chilled water tank 480 to the second heat exchanger 70 for waste heat, and a chilled water pipe 780 is provided from the second heat exchanger 70 for waste heat to the chilled water tank 480. A pump 727 is installed in pipe 760.

[0102] An example of the operation of such a heat recovery device 701 will be described next.

[0103] For example, various temperatures on the hot water side are assumed to be the same as in the fifth configuration. Furthermore, the various temperatures on the cold water side are assumed to be the same as in the fifth configuration, except as described below. The temperature of the chilled water on the branch pipe side of the three-way valve 402 is assumed to be 24°C in summer and 14°C in winter. The flow rate of chilled water from the chilled water tank 480 to the second heat exchanger 70 for waste heat is regulated by pump 727. Pump 727 is a heat exchange rate adjustment pump that adjusts the amount of heat exchanged between the waste hot water E2 and the chilled water in the second heat exchanger 70 for waste heat. The flow rate of chilled water passing through the second heat exchanger 70 for waste heat is assumed to be 14,541 L / h in summer and 6,907 L / h in winter.

[0104] Furthermore, the temperature of the process cooling water E1 is assumed to be the same as in the fifth embodiment. In addition, the temperature of the wastewater E2 is assumed to be the same as in the fifth configuration.

[0105] In the waste heat recovery device 701, the temperature of the chilled water in the first waste heat heat exchanger 61 is steadily increased by heat exchange with the chilled water using process cooling water E1, which has a more stable temperature than the waste hot water E2. For example, in summer, the control unit 90 sets the opening of the branch pipe of the three-way valve 402 to 0%, thereby setting the bypass chilled water flow rate to 0 and controlling the temperature increase of the 19°C chilled water entering the first waste heat heat exchanger 61 to 27°C. The temperature of the process cooling water E1 goes from 32°C to 24°C. In winter, the control unit 90 adjusts the opening of the branch pipe of the three-way valve 402 to adjust the bypass chilled water flow rate and controls the temperature increase of the 9°C chilled water entering the first waste heat heat exchanger 61 to 17°C. The temperature of the process cooling water E1 goes from 22°C to 14°C. The control unit 90 adjusts the amount of heat exchange between the chilled water and the process cooling water E1 by adjusting the flow rate of the bypassed chilled water, and controls the second temperature T2, which is the chilled water return temperature, to fall within a range that suppresses the shutdown of each heat pump 10. Furthermore, in the waste heat recovery device 701, the relatively unstable waste hot water E2 is used to supplementarily raise the temperature of the chilled water. For example, in summer, if the temperature of the waste hot water E2 is at the maximum of 70°C, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat exchanger 70, and the chilled water passing through the second waste heat exchanger 70 is heated from 27°C to 65°C before entering the chilled water tank 480. Also, in winter, if the temperature of the waste hot water E2 is at the maximum of 70°C, the temperature drops to 30°C through heat exchange with the chilled water in the second waste heat exchanger 70, and the chilled water passing through the second waste heat exchanger 70 is heated from 17°C to 65°C before entering the chilled water tank 480. Pump 727 controls the flow rate of chilled water passing through the second heat exchanger 70 for waste heat to, for example, 14,541 L / h in summer, and the flow rate of chilled water passing through the second heat exchanger 70 for waste heat to, for example, 6,907 L / h in winter. The temperature of the chilled water in the chilled water tank 480 is, for example, 32°C in summer and 20°C in winter. The control unit 90 controls the opening degree of each of the three-way valves 402 and at least one of the pumps 727 so that the temperature of the chilled water in the chilled water tank 480 becomes a set value (for example, 32°C in summer and 20°C in winter).

[0106] The control unit 90 monitors the change in the heat quantity of the process cooling water E1 using the first flow rate F1 and the 12th temperature T12, and monitors the change in the heat quantity of the waste hot water E2 using the second flow rate F2 and the 22nd temperature T22. When the control unit 90 detects that the heat content of the process cooling water E1 has increased to a predetermined level or higher, it controls the three-way valve 402 to increase the flow rate of chilled water to each branch pipe, reducing the amount of heat exchange between the chilled water and the process cooling water E1, and adjusting so that the second temperature T2 of the chilled water returning to each heat pump 10 reaches a set value. Furthermore, when the control unit 90 detects that the heat content of the waste hot water E2 has increased to a predetermined level or higher, it controls the pump 727 to reduce the flow rate of chilled water to the second waste heat exchanger 70, thereby reducing the amount of heat exchanged between the chilled water and the waste hot water E2, and adjusting the second temperature T2 of the chilled water returning to each heat pump 10 to a set value. Furthermore, when the control unit 90 detects that the heat content of the process cooling water E1 has decreased by a predetermined amount or more, and that the heat content of the waste hot water E2 has decreased by a predetermined amount or more, it preemptively reduces the output of each heat pump 10 to suppress a decrease in the first temperature T1 of the chilled water coming out of each heat pump 10 and the second temperature T2 of the chilled water returning from each heat pump 10 that would lead to shutdown. The control unit 90 uses the flow meter 65 and temperature sensor 66 to grasp the change in the heat quantity of the process cooling water E1, rather than the change in the heat quantity of the chilled water, and the flow meter 73 and temperature sensor 74 to grasp the change in the heat quantity of the waste hot water E2, and uses this information to control the three-way valve 402, the pump 727, and each heat pump 10. This allows for quick detection of changes in the amount of heat the chilled water is heated due to heat exchange with the waste heat medium E, thereby suppressing the shutdown of each heat pump 10, and ensuring that each heat pump 10 continues to operate even if the heat quantity of the waste heat medium E (especially the waste hot water E2) changes rapidly.

[0107] In the waste heat recovery system 701 described above, chilled water is heated by a waste heat medium E, which is a medium containing waste heat. The control unit 90 is connected to a waste heat quantity detection unit (flow meters 65, 73, temperature sensors 66, 74) that detects the amount of heat in the waste heat medium E. Based on the amount of heat detected by the waste heat quantity detection unit, the control unit 90 controls at least one of the hot water and chilled water. In the waste heat recovery system 701, the first waste heat exchanger 61 for the more stable process cooling water E1 is incorporated into the chilled water side circuit of each heat pump 10, while the chilled water circuit for the more unstable waste hot water E2 is independent of the chilled water side circuit of the heat pump 10 via a chilled water tank 480. Therefore, even if the heat content of the heat dissipation medium E changes rapidly, the operation of each heat pump 10 continues. Furthermore, heating by the more stable process cooling water E1 becomes the main heating source for the chilled water, further suppressing the shutdown of each heat pump 10.

[0108] Furthermore, there are multiple types of waste heat transfer medium E, including process cooling water E1 and waste hot water E2. Therefore, by combining different types of waste heat transfer medium E, the waste heat transfer medium E as a whole becomes more stable, and the operation of each heat pump 10 for recovering waste heat becomes easier to maintain. Furthermore, the heat discharged from the process cooling water E1, which is one of the heat dissipation fluids E, is stable. Therefore, it becomes easier to continue operating each heat pump 10 for recovering the heat discharge.

[0109] [9th form] Figure 17 is a block diagram of a heating and cooling device 801 according to the ninth embodiment of this disclosure. The heating and cooling device 801 is installed in a factory where both a heating load H (to be heated) and a cooling load C (to be cooled) may exist. The heating and cooling device 801 is a device that performs both heating and cooling. Factories may also generate waste heat (to be recovered). When waste heat is recovered, the heating and cooling device 801 can also be considered a waste heat recovery device. Furthermore, the cooling load C may include only one individual cooling load, such as the cooling of a single product cooling device, or it may include multiple individual cooling loads, such as the cooling of a product cooling device and the cooling of a machine heat-generating part cooling device. Also, in the heating and cooling device 801, the waste heat may be considered as the object to be cooled by the cooling load C, in which case the heating and cooling device 801 can also be considered as a waste heat recovery device. The fact that the heating and cooling device can be considered as a waste heat recovery device is similarly valid for other forms relating to heating and cooling devices.

[0110] The heating and cooling device 801 is equipped with multiple (four in this case) heat recovery type heat pumps 810, similar to the heat pump 10. Some of the multiple heat pumps 10 (one in this case) are designated as chilled water load regulators, while the other heat pumps 10 are designated as non-chilled water load regulators. Even the non-chilled water load regulator heat pumps 10 supply chilled water to the cooling load C. In addition, multiple chilled water load regulators may be provided. Furthermore, the heating and cooling device 801 is equipped with multiple CT811 units (four in this case). CT stands for Cooling Tower. Each CT811 is operated to suppress the hot water return temperature of the corresponding heat pump 10 and to continue the operation of the heat pump 10 when the heating load H is too low, etc.

[0111] Hot water from each heat pump 10 passes through its respective pipe 812 and is collected in a single pipe 833, leading to the heat exchanger 832 with a heating load H. Each pipe 812 is fitted with a solenoid valve 813. Each pipe 812 is connected to a branch pipe 814 that leads to the CT 811. Each branch pipe 814 is fitted with a solenoid valve 815. The heat exchanger 832 is connected to a pipe 844 for introducing the heat source, which branches off from pipe 843 through which the heat source flows, and to a pipe 846 for returning the heated heat source back to pipe 843. The heat source is, for example, hot water for production at around 45°C, beverage products, pharmaceuticals, chemical products, or manufacturing intermediates. A pump 845 is installed in pipe 844. The pump 845 adjusts the flow rate of the heat source in order to adjust the amount of heat exchange with the hot water to be heated. Hot water from the heat exchanger 832 enters the hot water tank 840 via pipe 834. The hot water tank 840 is connected to a pipe 849 to the hot water boiler B and to a pipe 847 from pipe 849 to the hot water boiler B. A pump 848 is installed in pipe 849. Pump 848 adjusts the flow rate of hot water from the hot water tank 840 to the hot water boiler B, thereby adjusting the amount of hot water heated by the hot water boiler B. The hot water boiler B is operated at a specific temperature so that the return hot water does not fall below a predetermined temperature. The hot water boiler B provides backup for the hot water temperature. The hot water boiler B is an additional heat source for the hot water. Pipe 842 from the hot water tank 840 branches off to pipes 822 leading to each heat pump 10, and returns to each heat pump 10 for hot water supply. Each pipe 822 is fitted with a pump 823 and a solenoid valve 824. Each pipe 822 is connected to a branch pipe 825 that leads to the CT 811. Each branch pipe 825 is fitted with a solenoid valve 828 and a pump 829.

[0112] Chilled water from each heat pump 10 passes through their respective pipes 816 and is collected in a single pipe 860, which then leads to the heat exchanger 862 for the cooling load C. A three-way valve 802 is interposed in pipe 860. Pipe 880 from heat exchanger 862 branches off into pipe 826 leading to each heat pump 10, and is connected back to each heat pump 10 for chilled water. A pump 827 is interposed in each pipe 826. A heat exchanger 870 is interposed in pipe 880 to recover the waste heat from the waste hot water E2. The heat exchanger 870 is connected to a pipe 871 for introducing waste hot water E2, which branches off from pipe 876 through which waste hot water E2 flows, and to a pipe 872 for returning the waste hot water E2, after heat recovery, back to pipe 876. A pump 877 is interposed in pipe 871. The pump 877 adjusts the flow rate of waste hot water E2 to adjust the amount of heat exchange between the waste hot water E2 and the chilled water. In addition, at least one of other waste heat sources and hot water from an air-cooled heat pump may be used instead of, or together with, waste hot water E2.

[0113] Furthermore, the heating and cooling device 801 has a control unit 890 similar to the control unit 90 in the first embodiment.

[0114] An example of the operation of such a heating and cooling device 801 will be described next. Figures 18 and 19 are flowcharts relating to the example of this operation.

[0115] For example, the chilled water supply temperature, which is the temperature of the chilled water supplied to the cooling load C via pipe 860, is assumed to be around 10°C, and the chilled water return temperature via pipe 880 is assumed to be around 17°C. Furthermore, the hot water supply temperature to the heat exchanger 832 on the hot water side (the temperature of the hot water in pipe 833) is assumed to be around 60°C, and the hot water return temperature, which is the temperature of the hot water in pipe 842, is assumed to be around 55°C. The flow rate of chilled water to the cooling load C is adjusted by a three-way valve 802. The three-way valve 802 is a heat quantity adjustment unit that adjusts the amount of cooling energy supplied to the cooling load C. Furthermore, the temperature of the wastewater E2 is expected to fluctuate, but is estimated to be around 35°C. The capacity of each pump 823 is set such that the difference between the hot water supply temperature and the hot water return temperature, which is the hot water temperature range, is 5°C when the output of each heat pump 810 is 100%.

[0116] The heat pump 810 operates based on the hot water outlet temperature of the heat pump 810, and the heat pump 810 of the chilled water load regulator is further controlled based on the chilled water supply temperature. The chilled water load regulator operates with a chilled water base to control the chilled water temperature to 7°C and simultaneously supplies hot water. The non-chilled water load regulator operates with a hot water base to control the hot water temperature to 60°C and simultaneously supplies chilled water. Furthermore, the control unit 890 controls the hot water boiler B based on the hot water inlet temperature of each heat pump 810. The hot water boiler B is started (ON) when the hot water in the hot water tank 840 is 53°C or lower, and stopped (OFF) when it exceeds 55°C. Furthermore, the control unit 890 controls the pump 877 related to the waste hot water E2 based on the cold water return temperature. Furthermore, the control unit 890 controls the amount of heat supplied to the heating load H using the pump 845 on the heating load H side. In addition, the control unit 890 controls the amount of cooling energy supplied to the cooling load C using the three-way valve 802.

[0117] If a stop command is received (YES in step S801), the control unit 890 stops all heat pumps 810 (step S802), stops hot water boiler B (step S803), and terminates the process. If there is no stop command (NO in step S801), the control unit 890 determines whether the INV output of the pump 877 on the waste hot water E2 side is below a predetermined lower limit (60% in this case) (step S804). INV is the inverter.

[0118] If the control unit 890 determines NO in step S804, it proceeds to step S811. On the other hand, if the control unit 890 determines YES in step S804, it proceeds to step S805 to determine whether or not the hot water boiler B is in operation.

[0119] If the control unit 890 is NO in step S805 and hot water boiler B is stopped, it returns to step S801 (Return To Start, RTS). On the other hand, if the answer in step S805 is YES, the control unit 890 executes loop 5 to adjust the INV output of the pump 877 on the waste hot water E2 side.

[0120] In loop 5, the control unit 890 increases the INV output of the pump 845 on the heating load H side (step S806). The hot water temperature is controlled by each heat pump 10 to a set value (60°C in this case). Next, the control unit 890 determines whether the load of the heat pump 10 of the operating chilled water load regulator is below a predetermined upper limit (in this case, 95%) (step S807).

[0121] If the answer in step S807 is NO, the control unit 890 increases the number of operating heat pumps 10 of the non-chilled water load regulator by 1 (step S808) and proceeds to step S809. On the other hand, if the control unit 890 is YES in step S807, it skips step S808 and proceeds to step S809.

[0122] In step S809, the control unit 890 determines whether the hot water return temperature related to the pipe 842 is above a predetermined upper limit (in this case, 56°C). If the answer in step S809 is YES, the control unit 890 executes loop 6 to adjust the hot water return temperature to a predetermined value (in this case, 55°C). Loop 6 is contained within loop 5. On the other hand, if the control unit 890 is NO in step S809, it skips loop 6 and continues with loop 5. In loop 6, the control unit 890 reduces the output of the hot water boiler B until the hot water return temperature reaches a specific temperature (in this case, 55°C) below a predetermined upper limit (step S810).

[0123] Regarding loop 5, when the control unit 890 increases the flow rate of the pump 845 on the heating load H side, the hot water outlet temperature of each heat pump 810 temporarily decreases. Therefore, the control unit 890 increases the output of the heat pump 810 of the non-chilled water load regulator (INV output increase) to bring the hot water outlet temperature to the set temperature (60°C). As the hot water output increases, the chilled water output also increases, so the control unit 890 increases the INV output of the pump 877 on the exhaust hot water E2 side. As a result, the chilled water temperature is prevented from becoming low enough to cause each heat pump 810 to shut down, and the operation of each heat pump 810 continues.

[0124] On the other hand, in step S811, which is the step to which the result is NO in step S804, the control unit 890 determines whether the INV output of the pump 877 on the waste hot water E2 side is above a predetermined upper limit (in this case, 80%). If the answer in step S811 is YES, the control unit 890 executes loop 7 to adjust the INV output of the pump 877 on the waste hot water E2 side to a predetermined value (in this case, 70%). On the other hand, if the control unit 890 is NO in step S811, it skips loop 7 and returns to step S801 (RTS).

[0125] In loop 7, the control unit 890 reduces the INV output of the pump 877 on the waste hot water E2 side (step S812). Furthermore, the control unit 890 determines whether the load of the heat pump 10 of the chilled water load regulator is above a predetermined lower limit (in this case, 50%) (step S813).

[0126] If the control unit 890 is NO in step S813, it proceeds to step S814, reduces the number of operating heat pumps 10 of the non-chilled water load regulator by 1, and then proceeds to step S815. On the other hand, if the control unit 890 is YES in step S813, it skips step S814 and proceeds to step S815.

[0127] In step S815, the control unit 890 determines whether the hot water return temperature related to the pipe 842 is below a predetermined lower limit (in this case, 54°C). If the answer in step S815 is YES, the control unit 890 executes loop 8 to adjust the hot water return temperature to a specific temperature (in this case, 55°C) above a predetermined lower limit. Loop 8 is contained within loop 7. On the other hand, if the control unit 890 determines NO in step S815, it skips loop 8 and returns to the beginning of loop 7 (step S812).

[0128] In loop 8, the control unit 890 determines whether or not the hot water boiler B is operating in automatic mode (step S816). If the answer in step S816 is NO, the control unit 890 sets the hot water boiler B to automatic operation mode (step S817) and proceeds to step S818. On the other hand, if the control unit 890 is YES in step S816, it skips step S817 and proceeds to step S818.

[0129] In step S818, the control unit 890 increases the output of the hot water boiler B. The control unit 890 then repeats the process of loop 8 until the hot water return temperature reaches 55°C.

[0130] Regarding loop 7, when the control unit 890 reduces the flow rate of pump 845 on the heating load H side, the hot water outlet temperature of each heat pump 810 temporarily rises. Therefore, each heat pump 810 performing hot water-based operation reduces its output (INV output reduction) to bring the hot water outlet temperature to the set temperature (60°C). If the hot water output decreases, the chilled water output decreases, so the control unit 890 reduces the INV output of the pump 877 on the waste hot water E2 side. Therefore, the chilled water temperature is prevented from being heated by the waste hot water E2, which would otherwise result in insufficient cooling.

[0131] The heating and cooling device 801 described above includes a pump 877 that adjusts the amount of heat exchange between the waste hot water E2 and the chilled water. Therefore, the control unit 890 can increase the output of pump 877 in response to the increase in the amount of cold water used in the chilled water due to the increase in the amount of hot water used in the chilled water due to the heating load H (increase in the flow rate of pump 845), or reduce the output of pump 877 in response to the decrease in the amount of cold water used in the chilled water due to the decrease in the amount of hot water used in the chilled water due to the decrease in the flow rate of pump 845. Thus, the operation of each heat pump 10 continues.

[0132] [10th form] Figure 20 is a schematic diagram of the heating and cooling device 901 according to the 10th embodiment, which is the same as the 9th embodiment except that a chilled water chiller 911 is provided in place of one heat pump 810. There are three heat pumps 810, one of which is a chilled water load regulator and the other two are non-chilled water load regulators. Note that the number of heat pumps 810 may be other than three. The number of chilled water load regulators may be multiple. Also, the number of chilled water chillers 911 may be multiple. In the heating and cooling device 901, components, parts, processes, etc. that are the same as those in the ninth embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0133] The chilled water chiller 911 cools the chilled water. Similar to the heat pump 810, the chilled water side of the chilled water chiller 911 is connected to a supply pipe 816 and a return pipe 826. On the hot water side of the chilled water chiller 911, only the CT811 is connected via the supply pipe 816 and the return pipe 825. A pump 928 is interposed in pipe 825.

[0134] An example of the operation of the heating and cooling device 901 will be described below. Figures 21 and 22 are flowcharts relating to the example of this operation.

[0135] If the answer to step S801 is YES, the control unit 890 stops each heat pump 810 (step S802), stops the chilled water chiller 911 (step S901), stops the hot water boiler B (step S803), and terminates the process. On the other hand, if the result in step S801 is NO, the control unit 890 proceeds to step S902 to determine whether the chilled water return temperature is above a predetermined lower limit (in this case, 17°C).

[0136] If the control unit 890 is NO in step S902, it proceeds to step S904. On the other hand, if the control unit 890 is YES in step S902, it determines in step S805 whether or not the hot water boiler B is in operation, and if NO, it increases the number of operating chilled water chillers 911 by one (step S903) and returns to step S801 (RTS). On the other hand, if the result in step S805 is NO, the control unit 890 processes loop 9. Loop 9, like Loop 5 in the ninth form, includes Loop 6 and has steps S806 to S810. However, instead of having the loop control purpose of the INV output of the pump 845 on the waste hot water E2 side in the ninth form, it has the loop control purpose of adjusting the chilled water return temperature to a predetermined value (15°C in this case). After processing loop 9, the control unit 890 returns to step S801 (RTS).

[0137] On the other hand, in step S904, the control unit 890 determines whether the chilled water return temperature is at a predetermined upper limit (in this case, 13°C). If the answer in step S904 is YES, the control unit 890 executes loop 10. On the other hand, if the control unit 890 is NO in step S904, it skips loop 10 and returns to step S801 (RTS).

[0138] In the loop 10 for setting the chilled water return temperature to a predetermined value (15°C in this case), the control unit 890 determines whether or not the chilled water chiller 911 is in operation (step S905). If the answer in step S905 is YES, the control unit 890 reduces the number of operating chilled water chillers 911 by 1 (step S906) and proceeds to step S812. On the other hand, if the control unit 890 is NO in step S905, it skips step S906 and proceeds to step S812.

[0139] The control unit 890 processes from step S812 onward in the same manner as in the ninth embodiment. Loop 10 includes loop 8.

[0140] The heating and cooling device 901 described above has a pump 877 that adjusts the amount of heat exchange between the waste hot water E2 and the chilled water. In addition, a chilled water chiller 911 is provided in the chilled water circuit. Therefore, the control unit 890 can control the cooling of the chilled water by controlling the chilled water chiller 911 in addition to controlling the pump 877. Consequently, the operation of each heat pump 10 continues.

[0141] [11th form] Figure 23 is a schematic diagram of the heating and cooling device 1001 according to the 11th embodiment, which is the same as the 10th embodiment except that a chilled water chiller 911 is provided in place of another heat pump 810. There are two heat pumps 810, both operating in chilled water follow mode, and both serve as hot water load regulators. There are two chilled water chillers 911, one of which is operated as a backup and is normally shut down. Note that the number of heat pumps 810 may be other than two. The number of chilled water load regulators may be other than two, and one or more non-hot water load regulators may be provided. Also, the number of chilled water chillers 911 may be other than two. In the heating and cooling device 1001, components, parts, processes, etc. that are the same as in the 10th embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0142] In the heating and cooling device 1001, the hot water tank 1040 is also interposed in the pipe 833. The temperature of the hot water in the hot water tank 1040 is assumed to be, for example, 60°C. The hot water boiler B is controlled to turn ON when the temperature of the hot water in the hot water tank 1040 is 59°C or lower, and to turn OFF when it exceeds 60°C. Between the hot water tank 1040 and the heat exchanger 832 of the heating load H in pipe 833, a pump 1045 and a three-way valve 1013 are positioned. The three-way valve 1013 is positioned on the heat exchanger 832 side of the pump 1045. A bypass pipe 1015 (branch pipe) is connected to the three-way valve 1013. The bypass pipe 1015 is connected to pipe 834. Hot water that passes through the bypass pipe 1015 returns to the hot water tank 1040 without entering the heat exchanger 832. Alternatively, the three-way valve 1013 may be omitted, and the flow rate of hot water to the heat exchanger 832 may be regulated by the pump 1045.

[0143] An example of the operation of the heating and cooling device 1001 will be described below. Figures 24 and 25 are flowcharts relating to the example of this operation.

[0144] The control unit 890 controls the hot water temperature using each heat pump 810 as a hot water load adjuster. If the heat pumps 810 cannot heat the hot water, the hot water boiler B is operated to compensate. Each heat pump 810 is operated based on the chilled water outlet temperature and controlled based on the hot water supply temperature. Furthermore, the control unit 890 controls the hot water boiler B based on the hot water temperature of the hot water tank 1040. Furthermore, the control unit 890 controls the pump 877 related to the waste hot water E2 based on the cold water return temperature. Furthermore, the control unit 890 controls the amount of heat supplied to the heating load H using the three-way valve 1013. In addition, the control unit 890 controls the amount of cooling energy supplied to the cooling load C using the three-way valve 802.

[0145] The control unit 890 processes steps S801 to S803 in the same manner as in the ninth embodiment. Furthermore, if the answer in step S801 is NO, the control unit 890 proceeds to step S1001 to determine whether the hot water supply temperature in the operating heat pump 810 is below a predetermined lower limit (in this case, 58°C).

[0146] If the control unit 890 is NO in step S1001, it proceeds to step S1020. On the other hand, if the control unit 890 is YES in step S1001, it executes a loop 11 to set the hot water supply temperature of the heat pump 810 to a predetermined value (in this case, 60°C) that is above the predetermined lower limit.

[0147] In loop 11, the control unit 890 increases the INV output of the pump 877 related to the waste hot water E2 (step S1002). Next, the control unit 890 determines whether the chilled water supply temperature is above a predetermined upper limit (in this case, 13°C) (step S1003).

[0148] If the response in step S1003 is YES, the control unit 890 executes loop 12 to adjust the chilled water supply temperature to a predetermined value (in this case, 10°C) above the predetermined lower limit, and then proceeds to step S1005. Loop 12 is included in loop 11. On the other hand, if the control unit 890 is NO in step S1003, it skips loop 12 and proceeds to step S1005. In loop 12, the control unit 890 increases the output of the chilled water chiller 911 (step S1004).

[0149] In step S1005, the control unit 890 determines whether the hot water supply temperature in the operating heat pump 810 is within a predetermined range (in this case, 60±1℃). If the answer in step S1005 is YES, the control unit 890 reduces the output of the hot water boiler B (step S1006) and returns to the beginning of loop 11. On the other hand, if the result in step S1005 is NO, the control unit 890 proceeds to step S1007 to determine whether the load on the operating heat pump 810 is below a predetermined upper limit (in this case, 95%). If the answer in step S1007 is YES, the control unit 890 returns to the beginning of loop 11. On the other hand, if the result in step S1007 is NO, the control unit 890 increases the output of the hot water boiler B (step S1008) and returns to step S801 (RTS).

[0150] Regarding loop 11, when the control unit 890 increases the INV output of the pump 877 on the waste hot water E2 side to increase the amount of heat exchange between the waste hot water E2 and the chilled water, the chilled water return temperature rises, and the chilled water outlet temperature of the heat pump 810, which is acting as a thermal load adjuster during operation, rises. Therefore, each heat pump 810 that is operating primarily with chilled water as a hot water load adjuster increases its output (INV output increase) to bring the chilled water outlet temperature to the set temperature (10°C). If the output of each heat pump 810 increases, the hot water output will also increase, thus preventing situations where the hot water temperature is insufficient to meet the heating load H.

[0151] In step S1020, which is the step to which the result is NO in step S1001, the control unit 890 determines whether the hot water supply temperature is above a predetermined upper limit (in this case, 62°C). If the control unit 890 is NO in step S1020, it returns to step S801 (RTS). On the other hand, if the answer in step S1020 is YES, the control unit 890 proceeds to step S1021 to determine whether or not the hot water boiler B is stopped.

[0152] If the answer in step S1021 is YES, the control unit 890 executes loop 13 to set the hot water supply temperature of each heat pump 810 to a predetermined value (60°C in this case). On the other hand, if the result in step S1021 is NO, the control unit 890 reduces the output of the hot water boiler B (step S1022) and returns to step S801 (RTS).

[0153] In loop 13, the control unit 890 reduces the INV output of the pump 877 related to the waste hot water E2 (step S1023), and further determines whether the chilled water supply temperature is below a predetermined lower limit (in this case, 7°C) (step S1024). If the answer to step S1024 is YES, the control unit 890 executes loop 14 to set the chilled water supply temperature to a predetermined value (10°C in this case) that is above the predetermined lower limit, and returns to the beginning of loop 13. Loop 14 is included in loop 13. On the other hand, if the control unit 890 is NO in step S1024, it skips loop 14 and returns to the beginning of loop 13. In loop 14, the control unit 890 reduces the output of the chilled water chiller 911 (step S1025).

[0154] Regarding loop 13, when the control unit 890 reduces the INV output of pump 877 to reduce the amount of heat exchange between the waste hot water E2 and the chilled water, the chilled water temperature drops. Therefore, each heat pump 810, which performs chilled water tracking operation as a chilled water load regulator, reduces its output (reduces INV output) to set the chilled water outlet temperature to the set temperature (10°C). The control unit 890 also reduces the output of the chilled water chiller 911 to set the chilled water supply temperature to the set temperature (10°C). If the output of each heat pump 810 decreases, the hot water temperature will decrease. Therefore, the hot water temperature will not become so high that it could lead to the shutdown of each heat pump 810, and the operation of each heat pump 810 will continue.

[0155] The heating and cooling device 1001 described above includes a heat pump 810 that performs chilled water-based operation and a pump 877 that adjusts the amount of heat exchange between the waste hot water E2 and the chilled water. Therefore, the control unit 890 can continue operating each heat pump 810 even in chilled water follow-up mode.

[0156] [12th form] Figure 26 is a schematic diagram of the heating and cooling device 1101 according to the 12th embodiment. The heating and cooling device 1101 is the same as the 11th embodiment, except that it is equipped with three heat pumps 810 for hot water-based operation, one chilled water chiller 911, a three-way valve 1177 is provided in place of the pump 877 on the exhaust hot water E2 side, and a chilled water tank 1180 is interposed in the return chilled water pipe 880. Note that the number of heat pumps 810 may be other than three. Also, the number of chilled water chillers 911 may be multiple. In the heating and cooling device 1101, components, parts, processes, etc. that are the same as those in the 11th embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0157] The three heat pumps 810, which operate primarily with hot water, all receive the same value from the control unit 890 for the set temperature of the hot water outlet (60°C in this case), and operate based on that set temperature (same setting remote control). Furthermore, when the hot water outlet temperature (hot water supply temperature) of each heat pump 810 becomes higher than the set temperature by a predetermined amount (in this case, 2°C) (in this case, 62°C), the operation of one of the operating heat pumps 810 is stopped (reduction in the number of units) in order to reduce the number of operating heat pumps 810 by one. Furthermore, when the hot water outlet temperature of each heat pump 810 falls below the set temperature by a predetermined amount (2°C in this case) (58°C in this case), the stopped heat pump 810 starts operating (increases the number of operating heat pumps 810) by one. Furthermore, each heat pump 810 will increase in number if the load factor exceeds a predetermined upper limit (85% in this case). Furthermore, each heat pump 810 will be reduced in number when its load factor falls below a predetermined lower limit (in this case, 30%). In addition, each heat pump 810 has a startup delay timer function that prevents consecutive additions of units within a predetermined startup delay period (in this case, 4 minutes) after the initial addition of units. Furthermore, each heat pump 810 has a stop delay timer function that prevents consecutive stop delays (in this case, 4 minutes) from occurring after a reduction in the number of units. Each heat pump 810 has the function of increasing or decreasing the number of units. At least one of the various functions for increasing or decreasing the number of units may be controlled by the control unit 890. The magnitude of the predetermined increase and the magnitude of the predetermined decrease may be different. Furthermore, the magnitude of the predetermined start delay time and the magnitude of the predetermined stop delay time may be different. Moreover, part or all of the load factor may be changed to a rotational speed corresponding to that load factor.

[0158] Furthermore, the control unit 890 controls the three-way valve 1177 related to the exhaust hot water E2 based on the cold water return temperature.

[0159] An example of the operation of the heating and cooling device 1101 will be described below. Figures 27 and 28 are flowcharts relating to the example of this operation.

[0160] For example, the chilled water supply temperature, which is the temperature of the chilled water supplied to the cooling load C via pipe 860, is assumed to be around 10°C, and the chilled water return temperature via pipe 880 is assumed to be around 15°C. In addition, the hot water outlet temperature of each heat pump 810 is assumed to be around 58°C, the hot water supply temperature to the heat exchanger 832 on the hot water side is assumed to be around 60°C, the hot water temperature in the hot water tank 1040 is assumed to be around 60°C, and the hot water return temperature, which is the temperature of the hot water in pipe 842, is assumed to be around 55°C.

[0161] The control unit 890 processes steps S801 to S803 in the same manner as in the ninth embodiment. Furthermore, if the answer in step S801 is NO, the control unit 890 proceeds to step S1101 to determine whether the chilled water return temperature in the operating heat pump 810 is above a predetermined upper limit (in this case, 17°C).

[0162] If the control unit 890 is NO in step S1101, it proceeds to step S1120. On the other hand, if the answer in step S1101 is YES, the control unit 890 determines whether or not the hot water boiler B is in operation (step S1102). If the answer in step S1102 is YES, the control unit 890 executes loop 15 to set the chilled water return temperature of the heat pump 810 to a predetermined value (in this case, 15°C) that is below the predetermined upper limit. Meanwhile, if the control unit 890 is NO in step S1102, it starts operating the chilled water chiller 911 (step S1103) and returns to step S801 (RTS).

[0163] In loop 15, the control unit 890 determines whether the chilled water return temperature is above a predetermined upper limit (in this case, 15°C) (step S1104). If the answer in step S1104 is YES, the control unit 890 proceeds to step S1105, increases the set value of the hot water outlet temperature of each heat pump 810 by a predetermined increase or more (in this case, 2°C), and controls the hot water temperature so that the hot water outlet temperature becomes such that an additional heat pump 810 is added, thereby prompting the addition of a heat pump 810 in step S1106.

[0164] On the other hand, if the control unit 890 determines NO in step S1104, it proceeds to step S1107 to increase the set value of the hot water outlet temperature of each heat pump 810 by 1°C, and then proceeds to step S1108 to determine whether the load of each heat pump 810 is above a predetermined upper limit (in this case, 85%). If the control unit 890 is NO in step S1108, it proceeds to step S1110. On the other hand, if the control unit 890 is YES in step S1108, it proceeds to step S1106 due to the function of increasing the number of heat pumps 810. After step S1106, which involves adding more heat pumps 810, the control unit 890 executes step S1109, increasing the set value of the hot water temperature of the heat pump 810 by 1, and then proceeds to step S1110. Step S1109 prompts the activation of the startup delay timer function, thereby preventing the situation of continuously adding more heat pumps.

[0165] In step S1110, the control unit 890 determines whether the temperature of the hot water in the hot water tank 1040 is higher than a predetermined upper limit (in this case, 60°C). If the answer to step S1110 is YES, the control unit 890 executes loop 16 to adjust the temperature of the hot water in the hot water tank 1040 to a predetermined value (60°C in this case) that is below the predetermined upper limit. Loop 16 is included in loop 15. On the other hand, if the control unit 890 is NO in step S1110, it skips loop 16 and returns to the beginning of loop 15. In loop 16, the control unit 890 reduces the output of the hot water boiler B (step S1111).

[0166] In step S1120, which is the step to which the result is NO in step S1101, the control unit 890 determines whether the chilled water return temperature is below a predetermined lower limit (in this case, 13°C). If the control unit 890 is NO in step S1120, it returns to step S801 (RTS). On the other hand, if the control unit 890 is YES in step S1120, it executes a loop 17 to set the chilled water return temperature to a predetermined value (in this case, 15°C) that is above the predetermined lower limit.

[0167] In loop 17, the control unit 890 determines whether or not the chilled water chiller 911 is in operation (step S1121). If the response in step S1121 is YES, the control unit 890 reduces the number of operating chilled water chillers 911 by 1 (step S1122) and returns to the beginning of loop 17.

[0168] On the other hand, if the control unit 890 determines NO in step S1121, it proceeds to step S1123 to determine whether the chilled water return temperature is below the predetermined lower limit (in this case, 10°C). If the answer in step S1123 is YES, the control unit 890 proceeds to step S1124, where it reduces the set value of the hot water outlet temperature of each heat pump 810 by a predetermined amount or more (in this case, 2°C), controlling the hot water temperature so that the hot water outlet temperature becomes such that the number of heat pumps 810 is reduced, thereby prompting the reduction of the number of heat pumps 810 in step S1125. In other words, in step S1123, it is determined whether or not the chilled water return temperature has dropped sharply, and if YES, in step S1124, the set value of the hot water temperature of each heat pump 810 is sharply reduced to encourage the activation of the reduction function.

[0169] On the other hand, if the control unit 890 determines NO in step S1123, it proceeds to step S1126 to decrease the set value of the hot water outlet temperature of each heat pump 810 by 1°C, and then proceeds to step S1127 to determine whether the load of each heat pump 810 is below a predetermined lower limit (in this case, 30%). If the control unit 890 is NO in step S1127, it proceeds to step S1129. On the other hand, if the control unit 890 is YES in step S1127, it proceeds to step S1125 due to the function of reducing the number of heat pumps 810. After step S1125 related to the reduction of the heat pump 810, the control unit 890 executes step S1128, decreases the set value of the hot water temperature of the heat pump 810 by 1, and proceeds to step S1129. By step S1128, the exertion of the stop delay timer function is promoted, and a situation where the reduction is continuously made is suppressed.

[0170] In step S1129, the control unit 890 determines whether the hot water temperature in the hot water tank 1040 is below a predetermined lower limit (here, 59°C). If the result in step S1129 is YES, the control unit 890 executes loop 18 to adjust the hot water temperature in the hot water tank 1040 to a predetermined value (here, 60°C) below the predetermined lower limit. Loop 18 is included in loop 17. On the other hand, if the result in step S1129 is NO, the control unit 890 skips loop 18 and returns to the start of loop 17.

[0171] In loop 18, the control unit 890 determines whether the hot water boiler B is operating in the automatic operation mode (step S1131). If the result in step S1130 is NO, the control unit 890 switches the hot water boiler B to the automatic operation mode (step S1131) and proceeds to step S1132. On the other hand, if the result in step S1131 is YES, the control unit 890 skips step S1132 and proceeds to step S1132. In step S1132, the control unit 890 increases the output of the hot water boiler B and returns to the start of loop 18.

[0172] The above heating and cooling device 1101 has a three-way valve 1177 for adjusting the heat exchange amount between the exhaust hot water E2 and the cold water. Further, the control unit 890 controls the number of units of each heat pump 10 by changing the set value of the set hot water temperature of each heat pump 10. Therefore, the continuous operation of each heat pump 10 is made easier.

[0173] [Form 13] The heating and cooling device according to the 13th embodiment is the same as that of the 12th embodiment, except for the operation of various components and the settings of each heat pump 810. In the heating and cooling device of the 13th embodiment, components, parts, processes, etc. that are the same as those of the 12th embodiment are appropriately denoted by the same reference numerals and their explanations are omitted.

[0174] In the 13th form of the heating and cooling system, the control unit 890 monitors the chilled water return temperature and adjusts the cooling to compensate for any deficiencies as appropriate. In addition, instead of the function of increasing or decreasing the number of units (number adjustment function) in the 12th form, it controls the system using a number adjustment function based on the maximum load limit setting of each heat pump 810.

[0175] The three heat pumps 810, which operate primarily with hot water, all receive the same maximum load limit setting from the control unit 890 and operate based on that setting (same setting remote control). Furthermore, when the load factor exceeds the maximum load limit, each heat pump 810 starts operating a stopped heat pump 810 (increases the number of operating heat pumps 810) to increase the number of operating heat pumps 810 by one. The startup delay timer function and shutdown delay timer function during load rate reduction are the same as in the 12th form.

[0176] An example of the operation of the heating and cooling device 1201 will be described below. Figures 29 and 30 are flowcharts relating to the example of this operation.

[0177] The control unit 890 processes steps S801 to S803 and S1101 to S1103 in the same manner as in the twelfth embodiment. Furthermore, if the answer in step S1102 is YES, the control unit 890 executes loop 19 to set the chilled water return temperature of the heat pump 810 to a predetermined value (15°C in this case).

[0178] In loop 19, the control unit 890 determines whether the chilled water return temperature is above a predetermined upper limit (here 17°C) and below a specific value (here 20°C) (step S1201). If the control unit 890 answers YES in step S1201, it proceeds to step S1202, increases the maximum load limit setting of each heat pump 810 by 20% (for example, increasing it from 60% to 80% by adding 20%), and then proceeds to step S1203. The 20% here is an example of a predetermined increase related to the maximum load limit setting.

[0179] If the significant increase in the maximum load limit in step S1202 prompts the load rate of each heat pump 810 to increase to a predetermined upper limit (85% in this case) or higher in step S1203 (YES in step S1203), then the number of heat pumps 810 is increased (step S1204). After the increase in the number of heat pumps, the process proceeds to step S1110. On the other hand, if the load factor of the operating heat pump 810 is below a predetermined upper limit, the number of heat pumps 810 will not be increased, and the process will proceed to step S1110. On the other hand, if the control unit 890 is NO in step S1201, it increases the maximum load limit setting value of each heat pump 810 by 10% (step S1205) and proceeds to step S1203. Here, 10% is an example of a specific increase less than or equal to a predetermined increase related to the maximum load limit setting value.

[0180] The control unit 890 processes from step S1110 onward, including loop 16 (step S1111), in the same manner as in the 12th embodiment.

[0181] In step S1120, which is the step to which the result is NO in step S1101, the control unit 890 determines whether the chilled water return temperature is below a predetermined lower limit (in this case, 13°C). If the control unit 890 is NO in step S1120, it returns to step S801 (RTS). On the other hand, if the control unit 890 is YES in step S1120, it executes a loop 20 to set the chilled water return temperature to a predetermined value (in this case, 15°C) that is above the predetermined lower limit.

[0182] In loop 20, the control unit 890 processes steps S1121 to S1123 in the same manner as in loop 17 of the 12th form. If the response in step S1123 is NO, the control unit 890 proceeds to step S1220, where it reduces the maximum load limit setting of each heat pump 810 by 10% (for example, from 60% to 50%), and then proceeds to step S1221. 10% is an example of a predetermined reduction related to the maximum load limit. In step S1221, if the load factor of each heat pump 810 is below a predetermined lower limit (in this case, 30%) (YES), the number of units is reduced (step S1224). Furthermore, the control unit 890, upon realizing that the load factor has fallen below the predetermined lower limit, sets the maximum load limit setting value of each heat pump 810 to a specific value greater than the predetermined lower limit (in this case, 40%) in step S1225, thereby suppressing continuous reduction in the number of units. On the other hand, if the answer in step S1221 is NO, the process in step S1129 is performed.

[0183] On the other hand, if the control unit 890 determines YES in step S1123, it further determines whether the chilled water return temperature is below a second specific value (here, 7°C) which is below a specific value (here, 10°C) (step S1222). If YES, it proceeds to step S1226, where it sets the maximum load limit setting of each heat pump 810 to a value corresponding to the load rate at which the thermostat will always turn OFF (stop operation). As a result, each heat pump 810 stops. Next, the control unit 890 proceeds to step S1227 and, similar to step S1222, determines whether the chilled water return temperature is below a second specified value (in this case, 7°C) which is below a specified value. If the answer in step S1227 is YES, the control unit 890 keeps each heat pump 810 stopped and waits until the hot water return temperature from the hot water boiler B exceeds a second specific value (steps S1228, S1227). On the other hand, if the control unit 890 is NO in step S1227, it proceeds to step S1129. Further, when the result in step S1222 is NO, the control unit 890 proceeds to step S1223, sets the specific lower limit (here, 29%) below the predetermined lower limit (here, 30%) of the maximum load limit value of each heat pump 810, promotes the reduction of the number of units of each heat pump 810 (step S1324), and proceeds to step S1225 to suppress continuous reduction of the number of units.

[0184] After step S1129, the control unit 890 performs the same processing as in the twelfth embodiment, including loop 18 (steps S1130 to S1132).

[0185] The heating and cooling device according to the above thirteenth embodiment has a three-way valve 1177 for adjusting the heat exchange amount between the discharged warm water E2 and the cold water. Further, the control unit 890 controls the number of units of each heat pump 10 by changing the set value of the maximum load limit value of each heat pump 10. Therefore, the continuous operation of each heat pump 10 can be made easier.

[0186] [Fourteenth Embodiment] FIG. 31 is a schematic diagram of a heating and cooling device 1301 according to the fourteenth embodiment. The heating and cooling device 1301 is the same as the eleventh embodiment related to the heat pump 810 for cold water-based operation, except that the configuration on the discharged warm water E2 side is omitted. For members, parts, processes, etc. that are the same as those in the eleventh embodiment in the heating and cooling device 1301, the same reference numerals are appropriately assigned and the description is omitted.

[0187] In the heating and cooling device 1301, the members from the heat exchanger 870 for recovering the waste heat of the discharged warm water E2 to the pump 877 are omitted. The cold water in the pipe 880 directly returns to each heat pump 810 and each cold water chiller 911. Further, each heat pump 810, similar to the thirteenth embodiment, can operate the set value of the maximum load limit in a batch operation, and can also control the number of operating units (increase or decrease) based on the maximum load limit or the like.

[0188] An operation example of the heating and cooling device 1301 will be described next. Figures 32 and 33 are flowcharts relating to the example of this operation.

[0189] For example, the chilled water supply temperature, which is the temperature of the chilled water supplied to the cooling load C via pipe 860, is assumed to be around 10°C, and the chilled water return temperature via pipe 880 is assumed to be around 17°C. In addition, the hot water outlet temperature of each heat pump 810 is assumed to be around 60°C, the hot water supply temperature to the heat exchanger 832 on the hot water side is assumed to be around 60°C, the hot water temperature in the hot water tank 1040 is assumed to be around 60°C, and the hot water return temperature, which is the temperature of the hot water in pipe 842, is assumed to be around 55°C.

[0190] The control unit 890 processes steps S801 to S803 and S1001 in the same manner as in the 11th embodiment. Furthermore, if the answer in step S1001 is YES, the control unit 890 proceeds to step S1301 and executes a loop 21 to set the hot water outlet temperature of each heat pump 810 to a predetermined value (60°C in this case).

[0191] In loop 21, the control unit 890 determines whether the hot water outlet temperature of each heat pump 810 is below a predetermined lower limit (in this case, 55°C) (step S1301). If the response in step S1301 is YES, the control unit 890 increases the maximum load limit setting of each heat pump 810 by 20% (step S1302), prompts for an increase in the number of heat pumps if the load rate of each heat pump 810 is above a predetermined upper limit (85% in this case) (YES in step S1303) (step S1304), and the process proceeds to step S1005. If the response in step S1303 is NO, no increase in the number of heat pumps is made, and the process proceeds to step S1003.

[0192] On the other hand, if the control unit 890 is NO in step S1301, it proceeds to step S1305, increases the maximum load limit setting of each heat pump 810 by a specific increase (in this case, 10%) that is less than or equal to a predetermined increase, and proceeds to step S1303.

[0193] The control unit 890 processes steps S1103 to S1008, including loop 12, in the same manner as in the 11th embodiment.

[0194] The control unit 890 processes step S1020, which is initiated if the answer in step S1001 is NO, and the subsequent steps S1021 to S1022, in the same manner as in the 11th embodiment. If the answer in step S1021 is NO, the control unit 890 executes a loop 22 to set the hot water outlet temperature of each heat pump 810 to a predetermined value (60°C in this case).

[0195] In loop 22, the control unit 890 determines whether the hot water outlet temperature of each heat pump 810 is below a specific upper limit (in this case, 65°C) (step S1320). If the response in step S1320 is NO, the control unit 890 lowers the maximum load limit setting of each heat pump 810 by 10% (step S1321). If the load rate of each heat pump 810 is below a predetermined lower limit (in this case, 30%) (YES in step S1322), the control unit proceeds to step S1325, reduces the number of operating heat pumps 810 by 1, and proceeds to step S1326. On the other hand, if the load rate of each heat pump 810 is not below a predetermined lower limit (NO in step S1322), the control unit 890 returns to step S801 (RTS).

[0196] On the other hand, if the result in step S1320 is YES, the control unit 890 determines whether the hot water outlet temperature of each heat pump 810 is below the second specified upper limit (in this case, 70°C) (step S1323). If the answer in step S1323 is NO, the control unit 890 sets the maximum load limit setting for each heat pump 810 to a specific lower limit (in this case, 29%) which is below the predetermined lower limit of the load factor (step S1324), prompting a reduction in the number of heat pumps 810 (step S1325), and then proceeds to step S1326. In step S1326, the control unit 890 sets the maximum load limit setting for each heat pump 810 to a third specific value (in this case, 40%) that is above a predetermined lower limit of the load factor, thereby suppressing continuous increases in the number of units, and returns to step S801 (RTS).

[0197] On the other hand, if the answer in step S1323 is YES, the control unit 890 forcibly sets the maximum load limit setting of each heat pump 810 to a predetermined value that leads to the thermostat being turned OFF (step S1327), stops all heat pumps 810, waits until the hot water supply temperature falls below a predetermined lower limit (step S1328), and then proceeds to step S1024. The control unit 890 processes from step S1024 onward, including loop 14 (step S1025), in the same manner as in the 11th embodiment.

[0198] The control unit 890 of the heating and cooling device 1301 controls the number of heat pumps 10 by changing the set value of the maximum load limit of each heat pump 10 that performs chilled water-based operation. Therefore, it becomes easier to continue operating each heat pump 10.

[0199] Finally, examples of further modifications to at least one of the above forms and examples of modifications will be described. At least one of the components of the waste heat recovery devices 1-701 and the heating / cooling devices 801-1301, the various formulas, the content and sequence of control steps, and the content of control commands may be changed to another functionally and logically equivalent one. [Explanation of symbols]

[0200] 1, 101, 201, 301, 401, 501, 601, 701... Heat recovery devices 801, 901, 1001, 1101, 1301...Heating and cooling equipment 10, 810 Heat Pump 40, 840, 1040... Hot water tanks 90, 890... Control Unit 202, 212, 402, 502, 802, 1013, 1177... Three-way valve (heat quantity adjustment section) 602, 611, 612, 613, 813, 815, 824, 828... Solenoid valves (heat quantity adjustment section) 911 ··Chilled water chiller B··Warm water ボイラー(other heat source) E··heat removal media E1··Engineering Cooling Water E2·· Drainage water J.·Steam (other heat source)

Claims

1. One or more heat pumps that supply hot water to a hot water circuit and receive it from the hot water circuit, and supply chilled water to a chilled water circuit and receive it from the chilled water circuit, A control unit for controlling the hot water and the cold water, It is equipped with, The aforementioned cold water is heated by a heat-dissipating medium, which is a medium that has waste heat. The control unit, It is connected to a heat dissipation amount detection unit that detects the amount of heat in the heat dissipation medium, Based on the amount of heat detected by the heat dissipation detection unit, control is performed on at least one of the heat dissipation medium, the hot water, and the cold water. A waste heat recovery device characterized by the following features.

2. There are multiple heat dissipation media. The waste heat recovery device according to feature 1.

3. The heat dissipation in at least one of the heat dissipation media is stable. The waste heat recovery device according to feature 2.

4. The chilled water is first heated by the heat dissipation medium whose average temperature is closest to the temperature of the chilled water related to the heat pump. The waste heat recovery device according to feature 2.

5. The chilled water circuit has a heat exchanger that performs heat exchange between the chilled water and the heat dissipation medium. The waste heat recovery device according to feature 1.

6. The control unit adjusts the flow rate of the chilled water introduced into the heat exchanger based on the amount of heat detected by the heat waste detection unit. The waste heat recovery device according to feature 5.

7. The control unit adjusts the flow rate of the heat exchanger's heat transfer medium based on the heat quantity detected by the heat quantity detection unit. The waste heat recovery device according to feature 5.

8. It has a heat exhaust medium side pump which is a pump that adjusts the flow rate of the heat exhaust medium, The control unit controls the heat exhaust medium pump to adjust the flow rate of the heat exhaust medium. The waste heat recovery device according to feature 7.

9. The heat exhaust amount detection unit comprises at least one of a temperature sensor for detecting the temperature of the heat exhaust medium and a flow meter for measuring the flow rate of the heat exhaust medium. The waste heat recovery device according to feature 1.

10. The control unit controls at least one of the output and the number of operating units of the heat pump according to the amount of heat detected by the heat waste detection unit. The waste heat recovery device according to feature 1.

11. The chilled water circuit includes a heat exchanger that performs heat exchange between the chilled water and the heat dissipation medium, a bypass pipe that returns the chilled water to the heat pump without passing it through the heat exchanger, and a control valve that adjusts at least one of the amount of chilled water supplied to the heat exchanger and the amount of chilled water supplied to the bypass pipe. The control unit controls at least one of the amount of chilled water supplied to the heat exchanger and the amount of chilled water supplied to the bypass pipe by the control valve, based on the amount of heat detected by the heat dissipation detection unit. The waste heat recovery device according to feature 1.

12. The hot water side circuit includes a hot water side heat exchanger that performs heat exchange between the hot water and the heating load side hot water heated by the hot water, and a heating load side hot water pump that adjusts the amount of heat from the heating load side hot water supplied to the hot water side heat exchanger. The control unit controls the heating load side hot water pump based on the heat quantity detected by the heat quantity detection unit to adjust the amount of heat supplied to the heating load side hot water to the hot water side heat exchanger. The waste heat recovery device according to feature 1.

13. The temperature of the hot water is controlled by the heat pump. The waste heat recovery device according to feature 1.

14. One or more heat pumps that supply hot water to a hot water circuit and receive it from the hot water circuit, and supply chilled water to a chilled water circuit and receive it from the chilled water circuit, A control unit for controlling the hot water and the cold water, It is equipped with, The aforementioned cold water is heated by a heat-dissipating medium, which is a medium that has waste heat. The chilled water side circuit has a heat exchanger that performs heat exchange between the chilled water and the heat dissipation medium. The control unit, It is connected to at least one of the following: a heat exhaust medium temperature detection unit for detecting the temperature of the heat exhaust medium, a heat exhaust medium flow rate detection unit for detecting the flow rate of the heat exhaust medium, a chilled water temperature detection unit for detecting the temperature of the chilled water, a chilled water flow rate detection unit for detecting the flow rate of the chilled water, and a hot water temperature detection unit for detecting the temperature of the hot water. Based on at least one of the following, the output of the heat pump and the number of operating units are controlled: the temperature of the heat medium detected by the heat medium temperature detection unit, the flow rate of the heat medium detected by the heat medium flow rate detection unit, the temperature of the chilled water detected by the chilled water temperature detection unit, the flow rate of the chilled water detected by the chilled water flow rate detection unit, and the temperature of the hot water detected by the hot water temperature detection unit. A waste heat recovery device characterized by the following features.

15. The control unit, Based on at least one of the following, the temperature of the chilled water, the flow rate of the chilled water, the rotational speed of the heat pump, and the load factor of the heat pump, the amount of cooling energy supplied by the heat pump is calculated, Based on the temperature of the heat dissipation medium and the flow rate of the heat dissipation medium, the amount of heat dissipated is calculated. Based on the amount of cooling and the amount of waste heat, control at least one of the output and number of operating heat pumps. The waste heat recovery device according to feature 14.

16. The hot water side circuit includes a hot water side heat exchanger that performs heat exchange between the hot water and the heating load side hot water heated by the hot water, and a heating load side hot water pump that adjusts the amount of heat from the heating load side hot water supplied to the hot water side heat exchanger. The control unit controls the heating load-side hot water pump based on at least one of the temperature of the heat exhaust medium detected by the heat exhaust medium temperature detection unit and the flow rate of the heat exhaust medium detected by the heat exhaust medium flow rate detection unit, thereby adjusting the amount of heat exchange between the heating load-side hot water and the hot water, and adjusting at least one of the output and number of operating heat pumps. The waste heat recovery device according to feature 14.

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