Control device, and control method for absorption refrigerator

Abstract

The present disclosure provides: a control device that efficiently operates an air conditioning system in which the waste heat of a power generation device is utilized in an absorption refrigerator; and a control method for the absorption refrigerator.　A control device according to the present disclosure controls an absorption refrigerator that is provided in an air conditioning system including a power generation device and that utilizes, as a heat source, waste hot water warmed by waste heat of the power generation device, the control device comprising: a reception unit that receives an activation instruction for the air conditioning system; and a control unit that, after reception of the activation instruction, determines, on the basis of the temperature of the waste hot water, a timing for transmitting an activation instruction to the absorption refrigerator.

Description

Control device and control method for absorption chiller

[0001] The present disclosure relates to a control device and a control method for an absorption chiller.

[0002] Patent Document 1 discloses an absorption chiller that utilizes waste heat from a power generation device.

[0003] Japanese Patent Application Laid-Open No. 2018-141564

[0004] The present disclosure provides a control device and a control method for an absorption chiller that efficiently operates an air conditioning system that uses waste heat from a power generation plant in an absorption chiller.

[0005] This specification includes the entire contents of Japanese Patent Application No. 2023-123213, filed on July 28, 2023. A control device in the present disclosure is provided in an air conditioning system including a power generation device, and controls an absorption chiller that uses waste hot water heated by waste heat from the power generation device as a heat source, and includes: a reception unit that receives a start-up instruction for the air conditioning system; and a control unit that, after receiving the start-up instruction, determines the timing to send a start-up instruction to the absorption chiller based on the temperature of the waste hot water.

[0006] The control method for an absorption chiller disclosed herein is a control method for controlling, by a control device, an absorption chiller that is provided in an air conditioning system including a power generation device and uses waste hot water heated by waste heat from the power generation device as a heat source, wherein, when the control device receives a start-up instruction for the air conditioning system, the control device determines the timing for sending a start-up instruction to the absorption chiller based on the temperature of the waste hot water, and sends the start-up instruction to the absorption chiller at the determined timing.

[0007] The control device and the control method for an absorption chiller disclosed herein can improve the operating efficiency at startup of an absorption chiller that utilizes waste heat from a power generation unit, thereby enabling efficient operation of an air conditioning system that utilizes waste heat from a power generation unit in an absorption chiller.

[0008] FIG. 1 is a schematic diagram of an air conditioning system according to a first embodiment. FIG. 2 is a diagram of an absorption chiller according to the first embodiment. FIG. 3 is a flowchart showing the operation of an air conditioning control device according to the first embodiment. FIG. 4 is a flowchart showing the operation of an air conditioning control device according to the first embodiment. FIG. 5 is an explanatory diagram showing an example of the operation of the air conditioning control device according to the first embodiment.

[0009] (Knowledge, etc. that formed the basis of the present disclosure) At the time the inventors arrived at the present disclosure, there was a technology in which waste heat from a power generation system that drives a generator using an engine or the like was utilized in an absorption chiller. However, the inventors discovered a problem with the conventional technology in that little waste heat was supplied to the absorption chiller immediately after the power generation system was started, making it difficult to operate the absorption chiller efficiently. In order to solve this problem, the inventors came up with the subject matter of the present disclosure. Therefore, the present disclosure provides a control device and a control method for an absorption chiller that efficiently operate an air conditioning system that utilizes waste heat from a power generation system in its absorption chiller.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) [1-1. Configuration] [1-1-1. Configuration of Air Conditioning System] Fig. 1 is a schematic configuration diagram of an air conditioning system 1 in Embodiment 1. The air conditioning system 1 is configured by connecting a power generation device 4 and a device that utilizes the waste heat of the power generation device 4 via a waste heat supply path 7. Fig. 1 shows a heating heat exchanger 5, a hot water heat exchanger 6, and an absorption chiller 10 as devices that utilize the waste heat. The air conditioning system 1 may have any number of power generation devices 4 and absorption chillers 10. The configuration and number of devices that utilize the waste heat are also any number. In this embodiment, as an example, a configuration will be described in which the air conditioning system 1 includes three power generation devices 4, heating heat exchangers 5, hot water heat exchangers 6, and two absorption chillers 10.

[0012] The power generation device 4 is a device that generates electricity by driving a generator 41 with a drive source. The drive source may be, for example, a gas engine or a diesel engine, and the type is not particularly limited. In this embodiment, an example is shown in which an engine 42 is used as the drive source.

[0013] The air conditioning system 1 recovers waste heat from the engine 42 of the power generation device 4 using a heat medium flowing through the waste heat supply path 7. For example, the power generation device 4 includes a radiator 43 that dissipates heat from the engine 42. The heat medium flowing through the waste heat supply path 7 is supplied to the radiator 43 by a pump 71. The radiator 43 exchanges heat between the waste heat of the engine 42 and the heat medium flowing through the waste heat supply path 7. The heat medium flowing through the waste heat supply path 7 is, for example, water, and may contain antifreeze, a rust inhibitor, or other additives. The water flowing through the waste heat supply path 7 is heated in the radiator 43 by the waste heat of the engine 42 and becomes hot water, which is then supplied to the heating utilization heat exchanger 5, the hot water utilization heat exchanger 6, and the absorption chiller 10. The hot water flowing through the waste heat supply path 7 is called waste hot water.

[0014] The radiator 43 may be configured to directly exchange heat between the water flowing through the waste heat supply path 7 and the engine 42. Alternatively, the radiator 43 may be configured to exchange heat between the water flowing through the waste heat supply path 7 and the cooling water of the engine 42.

[0015] The power generation device 4 may be a cogeneration system that utilizes the waste heat of the engine 42, for example, in a water heater. In this case, the radiator 43 exchanges heat between the heat medium that supplies the waste heat of the engine 42 to the waste heat utilization device and the water flowing through the waste heat supply path 7. As a result, the waste heat of the engine 42 that has been utilized in the power generation device 4 is supplied through the waste heat supply path 7.

[0016] The air conditioning system 1 includes a plurality of power generation units 4. The power generation units 4 are connected in parallel to a waste heat supply path 7. With this configuration, the waste heat of each power generation unit 4 is supplied to the heating heat exchanger 5, the hot water heat exchanger 6, and the absorption chiller 10 through the waste heat supply path 7.

[0017] The heating-utilization heat exchanger 5 is connected to the absorption chiller 10, and uses waste heat from the power generation device 4 to provide supplementary heating during heating operation of the absorption chiller 10. The waste heat supply path 7 is provided with a heating three-way valve 72 that switches between supplying and cutting off hot water from the waste heat supply path 7 to the heating-utilization heat exchanger 5.

[0018] The hot water heat exchanger 6 heats water for hot water supply using waste heat from the power generation device 4. Waste hot water is supplied to the hot water heat exchanger 6 through the waste heat supply path 7, while waste hot water is supplied through the hot water pipe 6A by the hot water pump 61. The hot water heat exchanger 6 heats the water flowing through the hot water pipe 6A with the waste heat from the power generation device 4 by exchanging heat between the waste hot water in the waste heat supply path 7 and the water flowing through the hot water pipe 6A. The water heated in the hot water heat exchanger 6 is supplied to a hot water supply device (not shown) connected to the hot water pipe 6A. The hot water pump 61 operates in conjunction with the operating state of the hot water supply device connected to the hot water pipe 6A. For example, if the temperature of the waste hot water in the hot water storage tank of the hot water supply device drops, the hot water pump 61 operates to supply the waste hot water heated in the hot water heat exchanger 6 to the hot water supply device. The waste heat supply path 7 is provided with a hot water three-way valve 76 that switches between supplying and blocking waste hot water from the waste heat supply path 7 to the hot water utilization heat exchanger 6 .

[0019] The absorption chiller 10 is a device that supplies chilled water and hot water for air conditioning by utilizing waste heat from the power generation unit 4. The absorption chiller 10 is also called an absorption chiller / heater. The absorption chiller 10 is connected to a hot water supply pipe 73 that branches off from the waste heat supply path 7, and waste hot water is supplied to the regenerator 15 of the absorption chiller 10 through the hot water supply pipe 73. The hot water supply pipe 73 is provided with a three-way valve 74 that switches between supplying and cutting off the waste hot water from the hot water supply pipe 73 to the absorption chiller 10.

[0020] In the air conditioning system 1 shown in FIG. 1 , the symbols T1, T2, T4, T5, T6, T7, T8, T9, and T10 indicate temperature sensors. In the following description, the temperature detected by the temperature sensor T1 will be referred to as temperature T1. The same applies to the temperature sensors T2, T5, T6, T9, and T10. The temperature sensor T1 is located downstream of the power generation unit 4 and upstream of the heating-utilization heat exchanger 5 in the flow direction of the waste hot water in the waste heat supply path 7. The temperature sensor T1 can detect the temperature of the waste hot water heated by the waste heat of the power generation unit 4. The temperature sensor T4 is located between the heating-utilization heat exchanger 5 and the absorption chiller 10 and detects the temperature of the waste hot water immediately before it flows from the waste heat supply path 7 into the absorption chiller 10. In controlling the absorption chiller 10, the temperature detected by the temperature sensor T4 is used as the temperature of the waste hot water supplied from the power generation unit 4 to the absorption chiller 10. The temperature sensor T5 is located between the absorption chiller 10 and the hot water heat exchanger 6 in the flow direction of the waste heat supply path 7. The temperature detected by the temperature sensor T5 is the temperature of the waste hot water supplied to the hot water heat exchanger 6.

[0021] [1-1-2. Configuration of Control System of Air Conditioning System] The air conditioning system 1 includes an air conditioning control device 2 that controls the absorption chiller 10 , and a power generation control device 3 that controls the power generation device 4 .

[0022] The multiple power generation devices 4 of the air conditioning system 1 are each connected to the power generation control device 3 by a communication line 1C. The power generation control device 3 controls the power generation devices 4. Control by the power generation control device 3 includes, for example, starting, operating, and stopping the power generation devices 4. There is no limit to the number of power generation devices 4 that the power generation control device 3 controls. The power generation control device 3 can operate all of the power generation devices 4 that are the subject of control by the power generation control device 3, operate only some of them, or stop all of the power generation devices 4.

[0023] The power generation control device 3 determines the number of power generation devices 4 to operate, depending on the utilization state of waste heat in the heating utilization heat exchanger 5 , the hot water utilization heat exchanger 6 , and the absorption chiller 10 , for example.

[0024] The power generation control device 3 is connected to the pump 71 via a communication line (not shown). The power generation control device 3 operates the pump 71 corresponding to the power generation device 4 that is to be operated, among the power generation devices 4 connected to the power generation control device 3. This is one example, and the pump 71 may be configured to start and stop operation in conjunction with the start and stop of operation of the power generation device 4, for example.

[0025] The air conditioning control device 2 is connected to each absorption chiller 10 constituting the air conditioning system 1 via a communication line 1B.

[0026] As shown in Fig. 1, the air conditioning control device 2 includes a control unit 201 and a storage unit 202. The control unit 201 is a computer including a CPU (Central Processing Unit), an MPU (Micro Processor Unit), a microcontroller, or another processor. The control unit 201 includes the above-mentioned processor, a ROM (Read Only Memory), and a RAM (Random Access Memory), and controls the absorption chiller 10 by executing a program using the processor. The storage unit 202 has a non-volatile storage area and stores the program executed by the processor and data processed by the processor.

[0027] The control unit 201 is connected to a communication unit 221, an input unit 222, and a display unit 223. The communication unit 221 is a communication device having a transmitter and a receiver. The communication unit 221 is connected to the power generation control device 3 via a communication line 1A. The communication unit 221 transmits and receives various signals and data to and from the power generation control device 3 in accordance with the control of the control unit 201. The communication unit 221 is connected to each absorption chiller 10 via a communication line 1B. The communication unit 221 transmits various signals and data related to the control of the absorption chiller 10 to the absorption chiller 10 in accordance with the control of the control unit 201.

[0028] The communication unit 221 is connected via communication lines (not shown) to the heating three-way valve 72, the three-way valve 74, the hot water supply three-way valve 76, the pump 51, and the hot water supply pump 61. The communication unit 221 operates each of the heating three-way valve 72, the three-way valve 74, and the hot water supply three-way valve 76 under the control of the control unit 201.

[0029] For example, when the heating-utilizing heat exchanger 5 is in an operable state, the communication unit 221 operates the heating three-way valve 72 to enable supply of waste hot water from the waste heat supply path 7 to the heating-utilizing heat exchanger 5. This allows the heating-utilizing heat exchanger 5 to utilize the waste heat of the power generation device 4. The communication unit 221 can also operate the heating three-way valve 72 to block the supply of waste hot water from the waste heat supply path 7 to the heating-utilizing heat exchanger 5. In this case, the heating-utilizing heat exchanger 5 cannot utilize the waste heat of the power generation device 4. Similarly, for example, when the hot water-utilizing heat exchanger 6 is in an operable state, the communication unit 221 operates the hot water-utilizing three-way valve 76 to enable supply of waste hot water from the waste heat supply path 7 to the hot water-utilizing heat exchanger 6. This allows the hot water-utilizing heat exchanger 6 to utilize the waste heat of the power generation device 4. In addition, the communication unit 221 can also operate the hot water three-way valve 76 to block the supply of waste hot water from the waste heat supply path 7 to the hot water utilization heat exchanger 6, in which case the hot water utilization heat exchanger 6 will be unable to utilize the waste heat from the power generation device 4.

[0030] The input unit 222 accepts input operations by an operator who manages the air conditioning control device 2. The input unit 222 outputs an operation signal indicating the input content to the control unit 201. The input unit 222 may be configured to accept input using, for example, another computer installed in a location different from the air conditioning control device 2.

[0031] The display unit 223 displays information related to the control performed by the air conditioning control device 2. The display unit 223 includes a display device such as a liquid crystal display, an LED (Light Emitting Diode) indicator, or other display device. The display unit 223 displays information corresponding to the operating state of the air conditioning control device 2 and the operating state of the absorption chiller 10.

[0032] The control unit 201 includes an acquisition unit 211 and a processing unit 212. The acquisition unit 211 and the processing unit 212 may be functional units configured by a processor executing a program.

[0033] The acquisition unit 211 acquires temperatures detected by the temperature sensors T1, T2, T4, T5, T6, T7, T8, T9, and T10. The processing unit 212 controls the air conditioning system 1 based on information acquired by the communication unit 221 through communication, input received by the input unit 222, and the detected temperatures acquired by the acquisition unit 211. For example, the processing unit 212 controls the operation of the absorption chiller 10 based on temperatures T1, T4, T13, and T14 indicating the temperature of the waste hot water supplied to the absorption chiller 10 from the waste heat supply path 7. The processing unit 212 also transmits information regarding the number of operating power generation units 4 to the power generation control device 3 based on the temperature of the waste hot water supplied to the absorption chiller 10, etc. Details of the operation of the control unit 201 will be described later with reference to a flowchart.

[0034] 2 is a configuration diagram of the absorption chiller 10 according to embodiment 1. The absorption chiller 10 is a water chiller / heater that supplies chilled water and hot water by using water as a refrigerant and an aqueous solution of lithium bromide (LiBr) as an absorbing liquid.

[0035] The absorption chiller 10 includes an evaporator 11, an absorber 12 arranged in parallel with the evaporator 11, an evaporator-absorber shell 13 housing the evaporator 11 and the absorber 12, a regenerator 15, and a condenser 16. The absorption chiller 10 also includes an indoor unit 17, a cooler 18, a gas burner 20, a dilute absorbent pump 31, a refrigerant pump 32, a concentrated absorbent pump 33, and a cooling water pump 35. In the absorption chiller 10, the above-mentioned components are connected by piping via a concentrated absorbent pipe 21, a dilute absorbent pipe 22, refrigerant pipes 23, 24, and 25, a cooling water pipe 26, a cold water pipe 27, and the like, to form a circulation path. The heating-use heat exchanger 5 shown in FIG. 2 may also be included in the configuration of the absorption chiller 10.

[0036] The pressure inside the evaporator-absorber barrel 13 is kept at a high vacuum state, and water, which serves as a refrigerant, evaporates in the evaporator 11 and moves inside the evaporator-absorber barrel 13 to the absorber 12. The water forms a liquid pool 11A at the bottom of the evaporator 11. The evaporator-absorber barrel 13 is provided with a refrigerant pipe 25 that opens at the bottom of the evaporator 11, and the end of the refrigerant pipe 25 is connected to a sprayer arranged above the evaporator 11. A refrigerant pump 32 is provided on the refrigerant pipe 25. The refrigerant pump 32 transports the water from the liquid pool 11A to the top of the evaporator 11, thereby spraying water inside the evaporator 11.

[0037] The evaporator 11 is connected to the indoor unit 17 via a chilled water pipe 27. The chilled water flowing through the chilled water pipe 27 exchanges heat with the air in a heat exchanger (not shown) of the indoor unit 17, and the chilled air is supplied to the room, thereby realizing cooling operation. The indoor unit 17 acts as a heat load for the absorption chiller 10.

[0038] Chilled water (brine) is circulated between the evaporator 11 and the indoor unit 17 through a chilled water pipe 27. A heat transfer pipe 27A formed as part of the chilled water pipe 27 is arranged inside the evaporator 11, and during cooling operation of the absorption chiller 10, the brine flowing through the heat transfer pipe 27A exchanges heat with the refrigerant and is cooled. During heating operation of the absorption chiller 10, the brine is heated in the heat transfer pipe 27A and sent to the indoor unit 17 through the chilled water pipe 27. A pump 51 for transporting the brine is provided in the chilled water pipe 27.

[0039] In the cold water pipe 27, a heating-utilization heat exchanger 5 is connected via a hot water pipe 5A to a path for circulating brine from the indoor unit 17 to the evaporator 11. The heating-utilization heat exchanger 5 exchanges heat between the brine returning from the indoor unit 17 to the evaporator 11 and the waste hot water flowing through the waste heat supply path 7.

[0040] As shown in FIG. 2 , the chilled water pipe 27 is provided with temperature sensors T7, T8, T13, and T14. Hereinafter, the temperature detected by the temperature sensor T7 will be referred to as temperature T7, and the same applies to the temperature sensors T8, T13, and T14. The temperature sensor T8 is disposed in the path where water flows from the indoor unit 17 to the heating-use heat exchanger 5, and the temperature sensor T7 is disposed in the path where water flows from the heating-use heat exchanger 5 to the evaporator 11. The temperature sensor T13 is disposed between the heating-use heat exchanger 5 and the evaporator 11 and detects the temperature of the brine flowing into the heat transfer pipe 27A. The temperature detected by the temperature sensor T13 is referred to as the inlet water temperature T13. The temperature sensor T14 is disposed between the evaporator 11 and the indoor unit 17 and detects the temperature of the brine flowing from the heat transfer pipe 27A to the indoor unit 17. The temperature detected by the temperature sensor T14 is referred to as the outlet water temperature T14. The inlet water temperature T13 corresponds to an example of a "chilled water inlet temperature," and the outlet water temperature T14 corresponds to an example of a "chilled water outlet temperature."

[0041] The absorber 12 has the function of absorbing the refrigerant vapor evaporated in the evaporator 11 into an absorbing liquid and maintaining the pressure inside the evaporator-absorber shell 13 at a high vacuum state. A dilute absorbent liquid reservoir 12A is formed in the lower part of the absorber 12 to accumulate dilute absorbent liquid that has absorbed the refrigerant vapor. One end of a dilute absorbent liquid pipe 22 having a dilute absorbent liquid pump 31 is connected to the dilute absorbent liquid reservoir 12A. The dilute absorbent liquid pump 31 is an inverter-controllable pump, and is configured so that the drive amount of the dilute absorbent liquid pump 31 can be varied by controlling the inverter frequency.

[0042] The dilute absorbent pipe 22 is provided between the absorber 12 and the regenerator 15 and opens into the inside of the regenerator 15. A hot water supply pipe 73 branching off from the waste heat supply path 7 is connected to the regenerator 15, and a heat transfer pipe 73A formed in a part of the hot water supply pipe 73 is disposed inside the regenerator 15.

[0043] The regenerator 15 uses the waste heat of the power generation device 4 and the gas burner 20 as heat sources for heating and regenerating the absorbent. Inside the regenerator 15, the dilute absorbent sent through the dilute absorbent pipe 22 forms an absorbent reservoir 15A. The heat transfer pipe 73A heats the absorbent reservoir 15A with waste hot water sent through the hot water supply pipe 73, thereby heating and regenerating the absorbent. The gas burner 20 is housed in a shell (not shown) attached to the regenerator 15. The gas burner 20 heats the absorbent reservoir 15A with a flame, thereby heating and regenerating the absorbent. The ignition and extinguishing of the gas burner 20 and the flow rate of the fuel gas supplied to the gas burner 20 are controlled by the air conditioning control device 2. For example, when there is insufficient heat from the heat transfer pipe 73A, the air conditioning control device 2 causes the gas burner 20 to perform heating to promote the thermal regeneration of the absorbent. The heat transfer tube 73A is a first heat source that heats the absorption liquid by utilizing waste heat from the power generation device 4, and the gas burner 20 is a second heat source. Under the control of the air conditioning control device 2, the absorption chiller 10 can be operated using only the heat transfer tube 73A as a heat source, or using both the heat transfer tube 73A and the gas burner 20 as heat sources.

[0044] One end of a concentrated absorption liquid pipe 21 is connected to the regenerator 15. The other end of the concentrated absorption liquid pipe 21 is connected to a sprayer provided at the top of the absorber 12. A concentrated absorption liquid pump 33 is provided on the concentrated absorption liquid pipe 21. The concentrated absorption liquid pump 33 sends the concentrated absorption liquid from the regenerator 15 to the absorber 12, and the sent concentrated absorption liquid is sprayed inside the absorber 12 by the sprayer.

[0045] One end of a refrigerant pipe 23 opens at the top of the regenerator 15. The other end of the refrigerant pipe 23 opens into the interior of the condenser 16, and the refrigerant separated from the dilute absorption liquid in the regenerator 15 is sent to the condenser 16 through the refrigerant pipe 23.

[0046] The absorber 12 and the condenser 16 are provided with cooling water pipes 26 for circulating cooling water sequentially through the absorber 12 and the condenser 16. The cooling water pipes 26 are connected to a cooler 18. The cooler 18 is, for example, a cooling tower, and cools the cooling water flowing through the cooling water pipes 26. A cooling water pump 35 is provided in the cooling water pipes 26. The cooling water cooled by the cooler 18 is transported to the absorber 12 by the cooling water pump 35, and cools the concentrated absorption liquid sprayed inside the absorber 12. The cooling water pipes 26 are arranged inside the condenser 16, and cool the water vapor in the condenser 16.

[0047] The above is the flow of the absorption liquid and refrigerant when the absorption chiller 10 performs cooling operation, and when the absorption chiller 10 performs heating operation, the on-off valve 37 provided on the cooling water pipe 26 is closed. In this case, water vapor heated in the regenerator 15 flows into the evaporator 11 without condensing in the condenser 16, and heats the heat transfer pipe 27A. As a result, the brine flowing through the heat transfer pipe 27A becomes hot, and this brine flows into the indoor unit 17, supplying hot water for heating.

[0048] During heating operation of the absorption chiller 10, the heating three-way valve 72 ( FIG. 1 ) is opened under the control of the air conditioning control device 2. With the heating three-way valve 72 open, waste hot water is supplied from the waste heat supply path 7 to the heating-utilizing heat exchanger 5, and heat is exchanged between the waste hot water and the brine. In this way, the heating-utilizing heat exchanger 5 heats the brine returning from the indoor unit 17 to the evaporator 11 with the waste heat of the power generation device 4, thereby achieving the effect of improving the heating efficiency of the absorption chiller 10.

[0049] The dilute absorbent pump 31, the refrigerant pump 32, the concentrated absorbent pump 33, the cooling water pump 35, and the on-off valve 37 are connected to the air conditioning control device 2 via control lines (not shown). The air conditioning control device 2 controls the above-mentioned components to cause the absorption chiller 10 to perform cooling operation and heating operation.

[0050] As shown in FIG. 1 , the air conditioning control device 2 is connected to each absorption chiller 10 included in the air conditioning system 1 via a communication line 1B. The air conditioning control device 2 individually controls the multiple absorption chillers 10 to perform cooling operation and heating operation. For example, when the air conditioning control device 2 receives an input from the input unit 222 of an instruction to start the absorption chiller 10, the air conditioning control device 2 starts operation of the absorption chiller 10. Furthermore, while the absorption chiller 10 is operating, the air conditioning control device 2 calculates an air conditioning load based on the inlet water temperature T13 and the outlet water temperature T14, and controls the operating state of the absorption chiller 10 in accordance with the calculated air conditioning load. Furthermore, for example, the air conditioning control device 2 controls the cooling water pump 35 and the on-off valve 37 to switch the absorption chiller 10 between cooling operation and heating operation.

[0051] [1-2. Operation of Air Conditioning System] Next, we will explain the operation of the air conditioning control device 2. The operation of the air conditioning control device 2 explained here relates to the processing when the air conditioning system 1 is started up under the control of the air conditioning control device 2. The air conditioning control device 2 corresponds to an example of a "control device", the input unit 222 corresponds to an example of a "reception unit", and the engine 42 corresponds to an example of a "drive source".

[0052] In this embodiment, the input unit 222 is configured to be able to accept input of a start instruction and a stop instruction for the air conditioning system 1. When the processing unit 212 accepts input of a start instruction via the input unit 222 while the air conditioning system 1 is stopped, the processing unit 212 performs control to start the air conditioning system 1. A state in which the air conditioning system 1 is stopped means, for example, a state in which the power generation device 4 and the absorption chiller 10 of the air conditioning system 1 are not operating. In this state, the air conditioning control device 2 does not control the heating three-way valve 72, the three-way valve 74, the hot water supply three-way valve 76, and other equipment such as pumps.

[0053] The processing unit 212 executes a series of startup sequences for starting up the air conditioning system 1. In the startup sequence of the air conditioning system 1, the processing unit 212 first starts up the power generation device 4. Specifically, the processing unit 212 transmits a startup signal instructing the startup of the power generation device 4 to the power generation control device 3 via the communication unit 221. In response to this startup signal, the power generation control device 3 controls the power generation device 4 and starts operation of the power generation device 4.

[0054] After the power generation device 4 is started, the processing unit 212 starts the absorption chiller 10. Specifically, the processing unit 212 transmits a start signal to the absorption chiller 10 via the communication unit 221. The start signal transmitted to the absorption chiller 10 is, for example, a signal instructing a drive unit (not shown) that operates the absorption chiller 10 to start up. The drive unit is, for example, a drive device that supplies power to the dilute absorbent pump 31, the refrigerant pump 32, the concentrated absorbent pump 33, the cooling water pump 35, the on-off valve 37, the three-way valve 74, etc. This drive device may also be a device that supplies power to a vacuum pump (not shown) that maintains a high vacuum inside the evaporator / absorber shell 13. The absorption chiller 10 may also include a controller that operates the dilute absorbent pump 31, the refrigerant pump 32, the concentrated absorbent pump 33, the cooling water pump 35, the on-off valve 37, the three-way valve 74, and the vacuum pump under the control of the air conditioning control device 2. In this case, the air conditioning control device 2 also transmits a start signal to the above-mentioned controller. In this way, the air conditioning control device 2 transmits the start signal, thereby starting the operation of the absorption chiller 10. The start signal corresponds to an example of a "start instruction."

[0055] The processing unit 212 determines the timing of transmitting a start-up signal to the absorption chiller 10 based on, for example, the temperature of waste hot water supplied from the power generation device 4 to the absorption chiller 10. Furthermore, the processing unit 212 performs control to switch the operation mode of the absorption chiller 10 in the start-up sequence.

[0056] As described above, the absorption chiller 10 uses a first heat source and a second heat source as heat sources for heating the regenerator 15. The first heat source is waste heat supplied from the power generation device 4, specifically, waste hot water flowing through the waste heat supply path 7. The second heat source is the gas burner 20. The processing unit 212 operates the absorption chiller 10 in a first operating mode that restricts the use of the second heat source, and a second operating mode that imposes looser restrictions on the use of the second heat source than the first operating mode. The first operating mode and the second operating mode are exclusively switched between. In the second operating mode, the absorption chiller 10 can use the gas burner 20, which is the second heat source, but this does not necessarily mean that the gas burner 20 is always used during operation in the second operating mode. For example, whether the absorption chiller 10 actually uses the gas burner 20 for heating is determined depending on the thermal load of the indoor unit 17, etc. The second operating mode may be a mode in which the use of the second heat source is not restricted at all, or may be a mode in which the restrictions are relaxed compared to the first operating mode.

[0057] The restriction on the use of the second heat source in the first operating mode may be such that the use of the second heat source is completely prohibited. In this case, the first operating mode is a mode in which the second heat source is not used as a heat source for the absorption chiller 10. The second operating mode is a mode in which both the first heat source and the second heat source can be used as heat sources. The restriction on the use of the second heat source in the first operating mode may be such that an upper limit is set on the frequency or duration of use of the second heat source. In this case, the second operating mode is a mode in which there is no upper limit on the frequency or duration of use of the second heat source, or the upper limit is higher than that in the first operating mode. The first operating mode may be called a burner-limited mode, and the second operating mode may be called a non-limited mode.

[0058] The processing unit 212 designates the operation mode of the absorption chiller 10 as the first operation mode when transmitting a start-up signal to the absorption chiller 10. After a standby time has elapsed since the absorption chiller 10 was started, the processing unit 212 transitions the absorption chiller 10 to the second operation mode.

[0059] The processing unit 212 determines the standby time based on the number of power generation units 4 in operation in the air conditioning system 1. In the air conditioning system 1, as described above, the power generation control device 3 determines the number of power generation units 4 to operate, for example, in accordance with the amount of power generation required by the power load. The processing unit 212 acquires the number of power generation units 4 in operation by communicating with the power generation control device 3, and determines the standby time based on the acquired number.

[0060] In the configuration example of the air conditioning system 1 shown in Fig. 1, an air conditioning control device 2 controls a plurality of absorption chillers 10. The air conditioning control device 2 starts one absorption chiller 10 when executing a start-up sequence. After starting one absorption chiller 10, the air conditioning control device 2 starts the other absorption chillers 10 depending on the thermal load of the absorption chiller 10, etc. Below, a series of start-up sequences when starting one absorption chiller 10 after receiving input of a start-up instruction for the air conditioning system 1 via the input unit 222 will be described.

[0061] 3 and 4 are flowcharts showing the operation of the air conditioning control device 2 in embodiment 1. In Fig. 3 and 4, steps S13, S21, and S23 are executed by the acquisition unit 211, and the other steps are executed by the processing unit 212.

[0062] When the air conditioning control device 2 receives an input of an instruction to start the air conditioning system 1 via the input unit 222 (step S11), it starts the power generation device 4 by sending a start-up signal for the power generation device 4 to the power generation control device 3 (step S12).

[0063] The air conditioning control device 2 acquires the temperature of the waste hot water in the waste heat supply path 7 (step S13). Specifically, the air conditioning control device 2 acquires the temperature T1, which is the temperature detected by the temperature sensor T1, in step S13.

[0064] The air conditioning control device 2 determines whether the temperature of the waste hot water acquired in step S13 is equal to or higher than a preset activation threshold (step S14). If the temperature of the waste heat is lower than the activation threshold (step S14: NO), the air conditioning control device 2 returns to step S13. The activation threshold is, for example, 65°C.

[0065] If the temperature of the waste hot water is equal to or higher than the start-up threshold (step S14: YES), the air conditioning control device 2 sends a start-up signal to the absorption chiller 10 (step S15). When sending the start-up signal in step S15, the air conditioning control device 2 sets the operation mode of the absorption chiller 10 to the first operation mode, and starts up the absorption chiller 10.

[0066] Next, the air conditioning control device 2 executes a standby time determination process (step S16). The standby time determination process is shown in detail in FIG.

[0067] 4, the air conditioning control device 2 acquires the outlet water temperature T14 (step S21). The air conditioning control device 2 determines the first standby time TE1 based on the temperature difference between the outlet water temperature T14 and a preset value corresponding to the outlet water temperature T14 (step S22). The preset value for the outlet water temperature T14 is, for example, 7°C.

[0068] A specific example of the processing of step S22 is shown below. The air conditioning control device 2 executes the calculation of the following formula (1) to find the temperature difference a between the outlet water temperature T14 and the set value. a = outlet water temperature T14 - set value (1) If the temperature difference a in the above formula (1) is a negative value (a < 0), the air conditioning control device 2 sets a = 0. Next, the air conditioning control device 2 calculates the first standby time TE1 by calculating the following formula (2): TE1 = 60 - 3 × a (2) The first standby time TE1 found by the above formulas (1) and (2) is in units of minutes, for example.

[0069] In this example, the higher the outlet water temperature T14, the shorter the first standby time TE1, and the lower the outlet water temperature T14, the longer the first standby time TE1. For example, if the outlet water temperature T14 is 25°C and the set value is 7°C, the first standby time TE1 is calculated as 6 minutes using the following formula (3): TE1 = 60 - 3 × (25 - 7) = 6 minutes (3)

[0070] The air conditioning control device 2 communicates with the power generation control device 3 via the communication unit 221 to acquire the number of operating power generation devices 4 (step S23). The air conditioning control device 2 determines the second standby time TE2 based on the acquired number of operating power generation devices 4 (step S24).

[0071] A specific example of the processing of step S24 is shown below. The air conditioning control device 2 calculates the ratio B of the number of operating power generation devices 4 to all power generation devices 4 provided in the air conditioning system 1 as a normalized value using the following formula (4): B = number of operating power generation devices 4 / total number of power generation devices 4 (4) The air conditioning control device 2 calculates the second standby time TE2 using the following formula (5) using the ratio B calculated using the above formula (4) and a preset parameter b. The value of the parameter b is, for example, 30. TE2 = b × B (5)

[0072] In this example, the second standby time TE2 is longer as the number of operating power generation devices 4 increases. For example, if the total number of power generation devices 4 is three, one operating power generation device 4 is present, and the parameter b is 30, the second standby time TE2 is calculated to be 6 minutes using the following formula (6): TE2=30×(1 / 3)=10 [minutes] (6) In the calculation exemplified above, the first standby time TE1 and the second standby time TE2 may be limited to integers to improve control efficiency.

[0073] The air conditioning control device 2 calculates the standby time based on the first standby time TE1 and the second standby time TE2 (step S25). For example, the air conditioning control device 2 determines the standby time as the sum of the first standby time TE1 and the second standby time TE2. After calculating the standby time, the air conditioning control device 2 proceeds to step S17 in FIG. 3.

[0074] In step S17, the air conditioning control device 2 determines whether or not a time equivalent to the standby time has elapsed since the start signal was sent to the absorption chiller 10 in step S15 (step S17). If the time equivalent to the standby time has not elapsed (step S17: NO), the air conditioning control device 2 waits in step S17.

[0075] If the time corresponding to the standby time has elapsed (step S17: YES), the air conditioning control device 2 switches the operation mode of the absorption chiller 10 to the second operation mode (step S18), and ends the start-up sequence.

[0076] Figure 5 is an explanatory diagram showing an example of the operation of the air conditioning control device 2. Figure 5(a) is a diagram showing an example of changes in temperature T1. Figure 5(b) shows the operating state of the power generation device 4, Figure 5(c) shows the operating state of the absorption chiller 10, and Figure 5(d) shows the execution state of the second operating mode of the absorption chiller 10.

[0077] In the example of Fig. 5(a), the timing when a start-up instruction is input to the air conditioning system 1 is assumed to be time P1. At time P1, the temperature T1 is lower than the start-up threshold value TH. When the power generation unit 4 starts operating at time P1, the temperature T1 starts to rise due to the waste heat of the power generation unit 4. When the temperature T1 reaches a temperature equal to or higher than the start-up threshold value TH at time P2, a start-up signal is output to the absorption chiller 10, and the absorption chiller 10 starts up.

[0078] After starting the absorption chiller unit 10, the air conditioning control device 2 waits for a waiting time L. At a time P3 when the waiting time L has elapsed, the air conditioning control device 2 switches the operation mode of the absorption chiller unit 10 to the second operation mode.

[0079] The set values, activation thresholds, parameters, and calculation formulas described in relation to the above operations are stored, for example, in the storage unit 202. The processing shown in the above formulas (1) to (6) is an example, and the air conditioning control device 2 can be configured to calculate the standby time L, the first standby time TE1, and the second standby time TE2 using more complex functions, tables, programs, or AI (artificial intelligence).

[0080] [1-3. Effects, etc.] As described above, the air conditioning control device 2 is provided in the air conditioning system 1 including the power generation device 4, and controls the absorption chiller 10 that uses, as a heat source, waste hot water heated by waste heat from the power generation device 4. The air conditioning control device 2 includes an input unit 222 that receives a start-up instruction for the air conditioning system 1. The air conditioning control device 2 includes a control unit 201 that, after receiving the start-up instruction, determines the timing of sending a start-up signal to the absorption chiller 10 based on the temperature of the waste hot water.

[0081] This can improve the operating efficiency at the start-up of the absorption chiller 10 that utilizes the waste heat of the power generation unit 4. For example, the absorption chiller 10 can be started after the temperature of the waste hot water supplied from the power generation unit 4 to the absorption chiller 10 has increased after the power generation unit 4 has been started. As a result, the absorption chiller 10 can be started after the power generation unit 4 has begun to supply waste heat to the absorption chiller 10, and the absorption chiller 10 can be operated efficiently immediately after the start-up of the absorption chiller 10. Therefore, the air conditioning system 1 that utilizes the waste heat of the power generation unit 4 in the absorption chiller 10 can be operated efficiently.

[0082] The air conditioning control device 2 includes a communication unit 221 that transmits a start-up signal to the absorption chiller 10. The air conditioning control device 2 transmits the start-up signal to the absorption chiller 10 in response to a change in the temperature of the waste hot water from a temperature lower than a preset start-up threshold to a temperature equal to or higher than the threshold.

[0083] According to this, the absorption chiller 10 starts up after the temperature of the waste hot water has risen due to the operation of the power generation unit 4. Therefore, immediately after the absorption chiller 10 starts up, the absorption chiller 10 can utilize the waste heat of the power generation unit 4. Therefore, when the air conditioning system 1 starts up, the absorption chiller 10 can be operated more efficiently.

[0084] The absorption chiller 10 can use either the waste hot water or a second heat source different from the waste hot water, or both the waste hot water and the second heat source, as a heat source. The control unit 201 operates the absorption chiller 10 in a first operation mode in which the second heat source is not used by transmitting a start-up signal, and then operates the absorption chiller 10 in a second operation mode in which both the waste hot water and the second heat source can be used as heat sources.

[0085] This makes it possible to prevent the absorption chiller 10 from using the second heat source due to the temperature of the waste hot water not having risen sufficiently immediately after the start of the absorption chiller 10. This makes it possible to prevent an increase in the energy used by the absorption chiller 10 until the temperature of the waste hot water has risen sufficiently. Therefore, the absorption chiller 10 can be operated more efficiently when the air conditioning system 1 is started up.

[0086] The control unit 201 determines a standby time for waiting for switching to the second operation mode, and operates the absorption chiller 10 in the second operation mode after the standby time has elapsed since the start-up signal was transmitted.

[0087] According to this, by keeping the absorption chiller 10 on standby in the first operation mode until the temperature of the waste heat has risen sufficiently, it is possible to suppress an increase in the energy used by the absorption chiller 10 immediately after startup. Therefore, when the air conditioning system 1 is started up, the absorption chiller 10 can be operated more efficiently.

[0088] The control unit 201 determines the standby time based on at least one of the chilled water inlet temperature and the chilled water outlet temperature of the absorption chiller 10 .

[0089] According to this, the standby time for which the absorption chiller 10 is kept on standby in the first operation mode is determined based on the magnitude of the thermal load of the absorption chiller 10. Therefore, the standby time can be determined taking into account the magnitude of the waste heat required by the absorption chiller 10 immediately after startup, which prevents the absorption chiller 10 from using the second heat source due to a shortage of waste heat relative to the thermal load. This prevents an increase in the energy used by the absorption chiller 10 immediately after startup. Therefore, the absorption chiller 10 can be operated more efficiently when the air conditioning system 1 is started up.

[0090] The air conditioning system 1 includes a plurality of power generation units 4. The control unit 201 determines the standby time based on at least one of the chilled water inlet temperature and the chilled water outlet temperature, and the number of power generation units 4 in operation in the air conditioning system 1. Specifically, the control unit 201 calculates a first standby time TE1 based on the outlet water temperature T14 on the outflow side of the absorption chiller 10 and a set value, calculates a second standby time TE2 based on the number of operating power generation units 4, and calculates the standby time L from the first standby time TE1 and the second standby time TE2.

[0091] According to this, the standby time is determined taking into consideration the magnitude of the thermal load of the absorption chiller 10 and the number of operating power generation units 4. The number of operating power generation units 4 affects the degree to which the temperature of the waste hot water increases due to the operation of the power generation units 4. Therefore, by operating the absorption chiller 10 in the first operation mode for only the standby time that reflects the degree to which the temperature of the waste hot water increases, it is possible to effectively prevent the absorption chiller 10 from using the second heat source due to insufficient waste heat for the thermal load of the absorption chiller 10. This makes it possible to prevent an increase in the energy used by the absorption chiller 10 immediately after startup. Therefore, it is possible to operate the absorption chiller 10 more efficiently when the air conditioning system 1 is started up.

[0092] The power generation device 4 has a generator and a drive source that drives the generator. The air conditioning system 1 has a waste heat supply path 7 that circulates and supplies waste hot water heated by waste heat from the drive source to the regenerator of the absorption chiller 10. The control unit 201 acquires the temperature of the waste hot water flowing from the waste heat supply path 7 into the regenerator 15 as the temperature of the waste heat supplied from the power generation device 4 to the absorption chiller 10.

[0093] This allows the temperature of the waste heat supplied from the power generation device 4 to the absorption chiller 10 to be efficiently detected as the temperature of the waste hot water flowing through the waste heat supply path 7 .

[0094] The control method of this embodiment is a control method for controlling, by an air conditioning control device 2, an absorption chiller 10 that is provided in an air conditioning system 1 including a power generation device 4 and uses, as a heat source, waste hot water that is heated by waste heat from the power generation device 4. In this control method, when a start-up instruction for the air conditioning system 1 is received by the air conditioning control device 2, the timing for transmitting a start-up signal to the absorption chiller 10 is determined based on the temperature of the waste hot water. The air conditioning control device 2 transmits the start-up signal to the absorption chiller 10 at the determined timing.

[0095] This makes it possible to improve the operating efficiency at the start-up of the absorption chiller 10 that utilizes the waste heat of the power generation unit 4. For example, the absorption chiller 10 can be started after the temperature of the waste hot water supplied from the power generation unit 4 to the absorption chiller 10 has increased after the power generation unit 4 has been started. As a result, the absorption chiller 10 can be started after the power generation unit 4 has begun to supply waste heat to the absorption chiller 10, and the absorption chiller 10 can be operated efficiently immediately after the start-up of the absorption chiller 10. Therefore, the air conditioning system that utilizes the waste heat of the power generation unit in the absorption chiller can be operated efficiently.

[0096] (Other Embodiments) As described above, the above-mentioned embodiments have been described as examples disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the above-mentioned embodiments to create new embodiments. Therefore, other embodiments will be described below as examples.

[0097] In the above-described embodiment, an example has been described in which the air conditioning control device 2 detects and processes temperature T1 as the temperature of the waste hot water supplied from the power generation device 4 to the absorption chiller 10. This is just one example, and for example, the air conditioning control device 2 may detect temperature T4 as the temperature of the waste hot water supplied from the power generation device 4 to the absorption chiller 10. In the above-described embodiment, instead of using the outlet water temperature T14 in the standby time determination process shown in FIG. 4 , the standby time may be determined using the inlet water temperature T13. In this case, by using a preset value for the inlet water temperature T13, various parameters, and an arithmetic expression, the standby time can be calculated in the same way as when the outlet water temperature T14 is used. Alternatively, the air conditioning control device 2 may determine the standby time using both the inlet water temperature T13 and the outlet water temperature T14.

[0098] In the above-described embodiment, for example, the control device that performs the processes shown in Figures 3 and 4 may be a device separate from the air conditioning control device 2. That is, in the air conditioning system 1 that includes the air conditioning control device 2 that controls the operation of the absorption chiller 10, the processes shown in Figures 3 and 4 may be executed by a device separate from the air conditioning control device 2.

[0099] The configuration of the absorption chiller 10 described in the above-described embodiment is an example. For example, the heat transfer tube 73A and the gas burner 20 do not need to be provided in the same location in the regenerator 15. A configuration in which a portion for heating the absorbing solution using the heat transfer tube 73A and a portion for heating the absorbing solution using the gas burner 20 are provided separately may be provided. Furthermore, the regenerator 15 may be divided into a first regenerator that heats and regenerates the absorbing solution using the heat transfer tube 73A and a second regenerator that heats and regenerates the absorbing solution using the gas burner 20. The absorption chiller 10 may be a double-effect refrigeration device having a low-temperature regenerator and a high-temperature regenerator. In the above-described embodiment, the gas burner 20 has been described as the second heat source of the regenerator 15. However, the absorption chiller 10 may be configured to include a heat source other than the gas burner 20.

[0100] The operation of the air conditioning control device 2 in the above-described embodiment can be realized as a program executed by a processor. This program can also be realized in a form stored in a non-transitory computer-readable storage medium. Alternatively, this program can be stored in a server device or the like, and the air conditioning control device 2 can download the program from the server device to realize the above-described operation. The processor of the control unit 201 may be configured with a single processor or multiple processors. The processor of the control unit 201 may also be hardware programmed to realize the corresponding functional units. The processor of the control unit 201 may be configured with, for example, an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0101] The configuration of the air conditioning control device 2 shown in Figure 1 is one example, and the specific implementation form is not particularly limited. In other words, it is not necessarily necessary to implement hardware corresponding to each unit individually, and it is also possible to configure the system so that a single processor executes a program to realize the functions of each unit. Furthermore, some of the functions realized by software in the above-mentioned embodiment may be implemented by hardware, or some of the functions realized by hardware may be implemented by software.

[0102] The step units of the operation shown in Figures 3 and 4 are divided according to the main processing content to make the operation easier to understand, and the operation is not limited by the way the processing units are divided or the names of the processing units. The operation may be divided into more step units depending on the processing content. Furthermore, one step unit may be divided so that it includes more processing. Furthermore, the order of the steps may be changed as appropriate within the scope of the present disclosure.

[0103] It should be noted that the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

[0104] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0105] (Technology 1) A control device is provided in an air conditioning system including a power generation unit and controls an absorption chiller that uses waste hot water heated by waste heat from the power generation unit as a heat source, the control device comprising: a reception unit that receives a start-up instruction for the air conditioning system; and a control unit that, after receiving the start-up instruction, determines the timing of transmitting the start-up instruction to the absorption chiller based on the temperature of the waste hot water. This makes it possible to improve the operating efficiency at the start-up of the absorption chiller that uses the waste heat of the power generation unit. Therefore, the air conditioning system that uses the waste heat of the power generation unit in the absorption chiller can be operated efficiently.

[0106] (Technology 2) The control device according to Technology 1 further includes a communication unit that transmits the start-up instruction to the absorption chiller, and transmits the start-up instruction to the absorption chiller in response to a change in the temperature of the waste hot water from a temperature lower than a preset start-up threshold to a temperature equal to or higher than the start-up threshold. This allows the absorption chiller to start up after the temperature of the waste hot water has risen due to operation of the power generation unit, so that the absorption chiller can utilize the waste heat of the power generation unit immediately after start-up. Therefore, the absorption chiller can be operated more efficiently when the air conditioning system is started up.

[0107] (Technology 3) The control device according to Technology 1, wherein the absorption chiller can use either the waste hot water or a second heat source different from the waste hot water, or both the waste hot water and the second heat source, as a heat source, and the control unit operates the absorption chiller in a first operation mode in which the second heat source is not used as a heat source by sending the start-up instruction, and then operates the absorption chiller in a second operation mode in which both the waste hot water and the second heat source can be used as heat sources. This prevents the absorption chiller from using the second heat source due to an insufficient rise in temperature of the waste hot water immediately after start-up of the absorption chiller, thereby reducing the energy used by the absorption chiller. Therefore, the absorption chiller can be operated more efficiently when the air conditioning system is started up.

[0108] (Technology 4) The control device according to Technology 3, wherein the control unit determines a standby time for waiting before switching to the second operation mode, and operates the absorption chiller in the second operation mode after the standby time has elapsed since the transmission of the start-up instruction. This makes it possible to reduce the energy used by the absorption chiller immediately after start-up. Therefore, the absorption chiller can be operated more efficiently when the air conditioning system is started up.

[0109] (Technology 5) The control device according to Technology 4, wherein the control unit determines the standby time based on at least one of the chilled water inlet temperature and the chilled water outlet temperature of the absorption chiller. This prevents the absorption chiller from using the second heat source due to a shortage of waste heat relative to the thermal load of the absorption chiller, thereby reducing the energy used by the absorption chiller immediately after startup. Therefore, the absorption chiller can be operated more efficiently when the air conditioning system is started up.

[0110] (Technology 6) The control device according to Technology 5, wherein the air conditioning system includes a plurality of the power generation devices, and the control unit determines the standby time based on at least one of the chilled water inlet temperature and the chilled water outlet temperature and the number of power generation devices operating in the air conditioning system. This allows the absorption chiller to operate in the first operation mode for only the standby time that reflects the degree of rise in the waste hot water temperature, effectively preventing the absorption chiller from using the second heat source. This reduces the energy used by the absorption chiller immediately after startup, allowing the absorption chiller to operate more efficiently when the air conditioning system is started.

[0111] (Technology 7) The control device according to Technology 1, wherein the power generation device has a generator and a drive source that drives the generator, the air conditioning system has a waste heat supply path that circulates and supplies waste hot water heated by waste heat from the drive source to a regenerator of the absorption chiller, and the control unit acquires the temperature of the waste hot water flowing into the regenerator from the waste heat supply path. This makes it possible to efficiently detect the waste heat supplied from the power generation device to the absorption chiller.

[0112] (Technology 8) A control method for controlling, by a control device, an absorption chiller that is provided in an air conditioning system including a power generation unit and uses waste hot water heated by waste heat from the power generation unit as a heat source, wherein, when a start-up instruction for the air conditioning system is received by the control device, the control device determines timing for transmitting the start-up instruction to the absorption chiller based on the temperature of the waste hot water, and transmits the start-up instruction to the absorption chiller at the determined timing. This makes it possible to improve the operating efficiency at start-up of the absorption chiller that uses waste heat from the power generation unit. Thus, the air conditioning system that uses waste heat from the power generation unit in the absorption chiller can be operated efficiently.

[0113] As described above, the control device and the control method for an absorption chiller according to the present invention can be used in a waste heat utilization air conditioning system that utilizes waste heat from a power generation device in an absorption chiller.

[0114] 1 Air conditioning system 1A, 1B, 1C Communication line 2 Air conditioning control device (control device) 3 Power generation control device 4 Power generation device 5 Heating use heat exchanger 5A Hot water pipe 6 Hot water use heat exchanger 6A Hot water pipe 7 Waste heat supply path 10 Absorption chiller 11 Evaporator 11A Liquid reservoir 12 Absorber 12A Dilute absorbent liquid reservoir 13 Evaporator-absorber shell 15 Regenerator 15A Absorbent liquid reservoir 16 Condenser 17 Indoor unit (heat exchanger) 18 Cooler 20 Gas burner 21 Concentrated absorbent liquid pipe 22 Dilute absorbent liquid pipe 23, 24, 25 Refrigerant pipe 26 Cooling water pipe 27 Cold water pipe 27A Heat transfer pipe 31 Dilute absorbent liquid pump 32 Refrigerant pump 33 Concentrated absorbent liquid pump 35 Cooling water pump 37 On-off valve 41 Generator 42 Engine (driving source) 43 Radiator 51, 71 Pump 61 Hot water supply pump 72 Heating three-way valve 74 Three-way valve 76 Hot water supply three-way valve 73 Hot water supply pipe 73A Heat transfer pipe 201 Control unit 202 Memory unit 211 Acquisition unit 212 Processing unit 221 Communication unit 222 Input unit (reception unit) T13 Inlet water temperature T14 Outlet water temperature

Claims

1. A control device that is provided in an air conditioning system including a power generation device and controls an absorption chiller that uses waste hot water heated by waste heat from the power generation device as a heat source, the control device comprising: a reception unit that receives a start-up instruction for the air conditioning system; and a control unit that, after receiving the start-up instruction, determines the timing of sending a start-up instruction to the absorption chiller based on the temperature of the waste hot water.

2. The control device according to claim 1, further comprising a communication unit which transmits the start-up instruction to the absorption chiller, and which transmits the start-up instruction to the absorption chiller in response to a change in temperature of the waste hot water from a temperature lower than a preset start-up threshold to a temperature equal to or higher than the start-up threshold.

3. The control device according to claim 1, wherein the absorption chiller can use either the waste hot water or a second heat source different from the waste hot water, or both the waste hot water and the second heat source as a heat source, and the control unit, by sending the start-up instruction, operates the absorption chiller in a first operation mode in which the second heat source is not used as a heat source, and thereafter operates the absorption chiller in a second operation mode in which both the waste hot water and the second heat source can be used as heat sources.

4. The control device according to claim 3, wherein the control unit determines a waiting time for waiting to switch to the second operation mode, and operates the absorption chiller in the second operation mode after the waiting time has elapsed since transmitting the start-up instruction.

5. The control device according to claim 4, wherein the control unit determines the standby time based on at least one of a cold water inlet temperature and a cold water outlet temperature of the absorption chiller.

6. The control device according to claim 5, wherein the air conditioning system is provided with a plurality of the power generation devices, and the control unit determines the standby time based on at least one of the cold water inlet temperature and the cold water outlet temperature and the number of the power generation devices in operation in the air conditioning system.

7. The control device described in claim 1, wherein the power generation device has a generator and a driving source for driving the generator, the air conditioning system has a waste heat supply path for circulating and supplying waste hot water heated by waste heat from the driving source to a regenerator of the absorption chiller, and the control unit obtains the temperature of the waste hot water flowing from the waste heat supply path into the regenerator.

8. A control method for controlling an absorption chiller that is installed in an air conditioning system including a power generation unit and uses waste hot water heated by waste heat from the power generation unit as a heat source by a control device, the control device determining, when receiving a start-up instruction from the air conditioning system, a timing for sending a start-up instruction to the absorption chiller based on the temperature of the waste hot water, and sending the start-up instruction to the absorption chiller at the determined timing.

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