air conditioning system

Abstract

An air conditioning system (10) comprises: a chiller (30) that performs heat exchange using circulating water; a plurality of indoor units (51-55) to which circulating water discharged from the chiller (30) is supplied; a storage battery (40) that assists with the power required for operation of the chiller (30); and a system control device (20) that controls the operation of the chiller (30), the operation of the plurality of indoor units (51-55), and charging / discharging of the storage battery (40). The system control device (20) uses a (COP) matrix for the chiller and an operating environment including the outside air temperature and the room temperature as a basis to calculate: a first COP value under a first operating condition in which the chiller (30) is operated without being assisted by stored power from the storage battery (40) so that the power consumption per unit time does not exceed a preset threshold value; and a second COP value under a second operating condition in which the chiller (30) is operated while being assisted by stored power from the storage battery (40) during a period shorter than that of the first operating condition so as to not exceed a threshold value. When the second COP value is higher than the first COP value, the system control device (20) executes operation of the chiller (30) under the second operating condition.

Description

[Technical Field]

[0001] The present invention relates to a system for air conditioning using a chiller. [Background technology]

[0002] A heat source system is described in Patent Document 1. The heat source system described in Patent Document 1 performs machine learning and controls the operation so that the COP (Coefficient of Performance) of the entire heat source system is highest. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6889343 Summary of the Invention [Problem to be solved by the invention]

[0004] Typically, during long holidays, the heat source (chiller) is turned off. For this reason, there is a large temperature difference between the outside temperature and the room temperature, especially on the first day after a long holiday. In particular, in buildings with high insulation, the room temperature is less likely to change in response to the outside temperature. For this reason, the chiller must be operated at high output to quickly bring the room temperature closer to the desired set temperature.

[0005] However, if the chiller output is increased indefinitely after the chiller and the indoor unit connected to the chiller are operated until the room temperature reaches the desired set temperature, there is a risk that the power consumption will exceed the threshold (average power in 30-minute intervals) of the contracted power (received power).

[0006] On the other hand, there is also a method of running the chiller at low output to generate residual heat before full-scale air conditioning begins. However, in this case, the chiller's low output means it operates in a range where the COP value is very poor. This is undesirable from an energy-saving perspective.

[0007] Therefore, an object of the present invention is to prevent power consumption per unit time from exceeding a preset threshold and to achieve efficient air conditioning using a chiller. [Means for solving the problem]

[0008] The air conditioning system of this invention comprises a chiller that performs heat exchange using circulating water, a plurality of air conditioning units to which the circulating water discharged from the chiller is supplied, a storage battery that assists in the power required to operate the chiller, and a system control device that controls the operation of the chiller, the operation of the plurality of air conditioning units, and the charging and discharging of the storage battery.

[0009] The system control device calculates, based on the operating environment including the outside air temperature and the room temperature and the COP matrix of the chiller, a first COP value under a first operating condition in which the chiller is operated without assistance from stored power from the storage battery so that power consumption per unit time does not exceed a preset threshold, and a second COP value under a second operating condition in which the chiller is operated with assistance from stored power from the storage battery for a shorter period than under the first operating condition so that the threshold is not exceeded. If the second COP value is higher than the first COP value, the system control device operates the chiller under the second operating condition.

[0010] In this configuration, if the chiller's COP value is higher when assisted by stored power from the storage battery than when not, air conditioning is performed with assistance from stored power from the storage battery. This allows air conditioning to be performed under the condition that power consumption does not exceed the threshold and the chiller's energy conversion efficiency is higher. [Effects of the Invention]

[0011] According to this invention, it is possible to prevent power consumption per unit time from exceeding a preset threshold value and to achieve efficient air conditioning using a chiller. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing an example of an air conditioning system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a functional block diagram showing an example of a chiller in an air conditioning system according to an embodiment of the present invention. [Figure 3] FIG. 3 is a graph showing an example of the COP for each rated output of a chiller. [Figure 4] FIG. 4 is a flowchart showing an example of a system control flow of the first control of the air conditioning system according to the embodiment of the present invention. [Figure 5] Figure 5(A) is a graph showing an example of the load power over time under the first operating condition during cooling, and Figure 5(B) is a graph showing an example of the load power over time under the second operating condition during cooling. [Figure 6] FIG. 6 is a graph showing an example of the difference in COP value between the presence and absence of discharge assistance. [Figure 7] FIG. 7 is a flowchart showing an example of a system control flow of the second control of the air conditioning system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] An air conditioning system according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing an example of an air conditioning system according to an embodiment of the present invention. Fig. 2 is a functional block diagram showing an example of a chiller in the air conditioning system according to an embodiment of the present invention.

[0014] 1, the air conditioning system 10 includes a system control device 20, a chiller 30, a storage battery 40, a plurality of indoor units 51-55, and piping 500. The plurality of indoor units 51-55 correspond to "air conditioners."

[0015] The air conditioning system 10 is installed in, for example, a building 90 having a plurality of rooms 91-95. Note that the number of rooms in the building 90 is not limited to this. Each of the plurality of indoor units 51-55 is installed in each of the plurality of rooms 91-95. For example, indoor unit 51 is installed in room 91, indoor unit 52 is installed in room 92, and indoor unit 53 is installed in room 93. Indoor unit 54 is installed in room 94, and indoor unit 55 is installed in room 95. Each of the plurality of indoor units 51-55 is responsible for air conditioning each of the plurality of rooms 91-95. The plurality of indoor units 51-55 are connected to a chiller 30 via piping 500.

[0016] The chiller 30 and the storage battery 40 are installed, for example, on the roof of a building 90 that provides air conditioning. The storage battery 40 may be installed in a location other than the roof. The system control device 20 is installed in a predetermined position in the building 90.

[0017] The storage battery 40 is connected to the power supply control unit 22. The storage battery 40 is a rechargeable secondary battery.

[0018] The system control device 20 includes a control unit 21 and a power supply control unit 22 .

[0019] The control unit 21 is connected to the chiller 30 and the power supply control unit 22. The control unit 21 is also connected to a communications network. The control unit 21 acquires, for example, the COP matrices of the chiller 30 and the multiple indoor units 51-55 via the communications network. The control unit 21 also acquires the operating environment (for example, predicted temperature over time, sunshine hours, etc.) for the prediction target period (for example, tomorrow).

[0020] The control unit 21 selects the operating conditions for the chiller 30 based on the outside air temperature, the room temperature, the COP matrix, and the operating environment for the prediction period. The control unit 21 provides the selected operating conditions to the chiller 30 and the supply power control unit 22.

[0021] Generally speaking, the operating conditions include the output value of the chiller 30, the operating time, whether or not to assist in discharging from the storage battery 40, etc. The specific contents of the operating conditions and the method for selecting the operating conditions will be described later.

[0022] A commercial AC power supply is connected to the supply power control unit 22. Based on the operating conditions, the supply power control unit 22 selects between control for supplying the stored power of the storage battery 40 to the chiller 30 (discharge assist control) and control for not supplying the stored power of the storage battery 40 to the chiller 30.

[0023] When discharge assist control is selected, supply power control unit 22 controls the discharge of storage battery 40 and supplies the stored power of storage battery 40 together with power from the commercial AC power supply to chiller 30. When discharge assist control is not selected, supply power control unit 22 supplies only power from the commercial AC power supply to chiller 30.

[0024] Chiller 30 is operated by power supplied only from the commercial AC power supply or by power supplied assisted by stored power from storage battery 40. During operation, chiller 30 exchanges heat with circulating water returning from piping 500 and discharges the circulating water after heat exchange into piping 500. At this time, chiller 30 is operated based on operating conditions from control unit 21.

[0025] The chiller 30 has the configuration shown in Fig. 2. As shown in Fig. 2, the chiller 30 includes a heat exchanger 31, an expansion valve 32, a radiator 33, three-way valves 341 and 342, an accumulator 35, a compressor 36, and a pump 37. The piping 500 is connected to the heat exchanger 31.

[0026] Generally speaking, during cooling, the chiller 30 cools the circulating water (hot water) that has returned to the heat exchanger 31 through the piping 500 and discharges it into the piping 500. On the other hand, during heating, the chiller 30 heats the circulating water (cold water) that has returned to the heat exchanger 31 through the piping 500 and discharges it into the piping 500.

[0027] At this time, the chiller 30 adjusts the cooling capacity or heating capacity by adjusting the operating state of the compressor 36 based on the operating conditions. The operation of the compressor 36 uses electric power assisted by the stored power of the storage battery 40, or electric power from the commercial AC power source alone.

[0028] The chiller 30 circulates circulating water between the multiple indoor units 51-55 through piping 500. As a result, during cooling, the chiller 30 supplies circulating water (chilled water) to the multiple indoor units 51-55. The multiple indoor units 51-55 exchange heat between the circulating water (chilled water) and the air, thereby realizing cooling air conditioning for the multiple rooms 91-95. On the other hand, during heating, the chiller 30 supplies circulating water (hot water) to the multiple indoor units 51-55. The multiple indoor units 51-55 exchange heat between the circulating water (hot water) and the air, thereby realizing heating air conditioning for the multiple rooms 91-95.

[0029] In this air conditioning system 10, the chiller 30 and the multiple indoor units 51-55 have a COP, which is an index of air conditioning efficiency relative to power consumption. Fig. 3 is a graph showing an example of the COP for each rated output of the chiller. The COP is expressed as a COP value relative to power consumption. As shown in Fig. 3, the COP of the chiller 30 and the multiple indoor units 51-55 varies depending on the rated output.

[0030] However, regardless of whether the rated output is low or high, the COP value is low in the range of low power consumption, increases as power consumption increases, and after the COP value reaches a maximum, the COP value decreases as power consumption increases. Therefore, the chiller 30 operates with a low (poor) COP value at low output. In particular, when the rated output is high, the COP value will operate with a low (poor) COP value over a wider range of low power consumption.

[0031] For this reason, it is preferable to operate the chiller 30 at a power consumption closer to the maximum value, rather than operating in a region with low power consumption whenever possible. However, as described in the problem section, if the chiller output is increased without limit, the power consumption will exceed the threshold (average power in 30-minute intervals) of the contracted power (received power), which will increase the contract fee and make it uneconomical.

[0032] Furthermore, within the range where the power consumption does not exceed the contracted power, it is more economical to use the received power than to use the power stored in the storage battery 40.

[0033] Taking these into consideration, the control unit 21 controls the operation of the chiller 30 and controls the discharge assistance from the storage battery 40 as follows.

[0034] (First control method) Fig. 4 is a flowchart showing an example of a system control flow of the first control of the air conditioning system according to an embodiment of the present invention. Fig. 5(A) is a graph showing an example of the load power over time under a first operating condition during cooling, and Fig. 5(B) is a graph showing an example of the load power over time under a second operating condition during cooling. The general load power shown by the solid line in Figs. 5(A) and 5(B) is the load power other than the air conditioning used in the building 90, and the air conditioning load power shown by the dotted line is the load power used to operate the chiller 30 and the multiple indoor units 51-55. The dashed and dotted lines in Figs. 5(A) and 5(B) represent room temperature. Fig. 6 is a graph showing an example of the difference in COP value depending on whether or not discharge assistance is provided.

[0035] The control unit 21 acquires the COP matrices of the chiller 30 and the indoor units 51-55 via the communication network (S11). The control unit 21 acquires the operating environment for the prediction period (for example, tomorrow) via the communication network (S12). The operating environment includes the change in the outside temperature and the weather (hours of sunshine, etc.) during the prediction period.

[0036] During the full-scale operation period, the control unit 21 sets the output of the chiller 30 during full-scale operation so that the room temperature is within a temperature range relative to a desired set temperature (for example, within a temperature range that does not cause discomfort to the occupants). Then, the control unit 21 performs the following control.

[0037] (Calculation of the first COP value under the first operating condition (without discharge assistance of the storage battery 40 and with residual heat operation)) Control unit 21 calculates the output of chiller 30 when residual heat operation is performed within a range in which the total power of general load power and air conditioning load power does not exceed the contracted power (first operating condition) (S21). Specifically, control unit 21 does not assist discharge from storage battery 40. Furthermore, as shown in FIG. 5(A), for example, when full-scale air conditioning is to be performed using chiller 30 and multiple indoor units 51-55 from 6:00, control unit 21 operates chiller 30 at low output for a predetermined time before 6:00 (for example, in the case of FIG. 5(A), for four hours from around 2:00).

[0038] Control unit 21 calculates a first COP value under the first operating condition based on the outside air temperature, room temperature, the chiller output value during residual heat operation, and the COP matrix (S22). More specifically, control unit 21 refers to the COP matrix to calculate the first COP value according to the combination of the outside air temperature, room temperature, and the chiller output value during residual heat operation.

[0039] (Calculation of the second COP value under the second operating condition (with discharge assistance of the storage battery 40 and without use of residual heat operation)) Control unit 21 calculates the output of chiller 30 when discharge assistance from storage battery 40 is performed without performing residual heat operation within a range in which the total power of general load power and air conditioning load power does not exceed the contract power (second operating condition) (S31). Specifically, as shown in FIG. 5(B), control unit 21 calculates the output of chiller 30 when full-scale operation of chiller 30 begins within a range in which the range in which the output of chiller 30 exceeds the contract power can be offset by discharge assistance from storage battery 40. Because residual heat operation is not performed, the operating time of chiller 30 under the second operating condition is shorter than under the first operating condition.

[0040] Control unit 21 calculates a second COP value under the second operating condition based on the outside air temperature, room temperature, the chiller output value during discharge assistance, and the COP matrix (S32). More specifically, control unit 21 refers to the COP matrix to calculate the second COP value according to the combination of the outside air temperature, room temperature, and the chiller output value during discharge assistance. Note that the room temperature can be obtained, for example, from the water temperature measured by a temperature sensor installed in piping 500 to which circulating water in chiller 30 returns.

[0041] (Selection of operating conditions) The control unit 21 compares the first COP value with the second COP value.

[0042] If the second COP value is higher than the first COP value (S40: YES), the control unit 21 operates the chiller 30 using discharge assistance from the storage battery 40 without performing residual heat operation (S51). For example, as shown in FIG. 6, when residual heat operation is performed, the power consumption is 22 kW, and when discharge assistance from the storage battery 40 is performed, the power consumption is 44 kW. The COP value is higher when the power consumption is 44 kW. As a result, the control unit 21 performs discharge assistance without performing residual heat operation.

[0043] On the other hand, if the second COP value is equal to or less than the first COP value (S40: NO), the control unit 21 does not assist discharge from the storage battery 40, and performs preheat operation of the chiller 30 (S52).

[0044] By performing such control, the air conditioning system 10 can prevent the power consumption per unit time from exceeding a preset threshold (contracted power), and can also achieve efficient air conditioning using the chiller 30.

[0045] In the above-described configuration, the power supply control unit 22 controls the charging of the storage battery 40 to a predetermined SOC or higher when the chiller 30 is not operating. This allows the air conditioning system 10 to more reliably secure the stored power required for the above-described discharge assistance.

[0046] Furthermore, in the above-described air conditioning system 10, it is preferable to perform the above-described control taking into account the stored power (SOC) of the storage battery 40. Specifically, it is preferable for the air conditioning system 10 to calculate the second COP value assuming that the above-described discharge assistance will be performed within a range of power consumption (stored power) that the storage battery 40 can assist in discharging. This enables the air conditioning system 10 to prevent power consumption per unit time from exceeding a preset threshold (contracted power), and more reliably achieve efficient air conditioning using the chiller 30.

[0047] (Second control method) 7 is a flowchart showing an example of a system control flow of the second control of the air conditioning system according to the embodiment of the present invention. Note that the second control is the same as the first control (see FIG. 4) up to step S12, and therefore a description of the same parts will be omitted.

[0048] (Calculation of first total power amount α under first operating condition (no discharge assistance of storage battery 40, with residual heat operation)) The control unit 21 calculates the output and total operating time (residual heat operation time + full-scale operation time) of the chiller 30 when residual heat operation is performed within a range in which the total power of the general load power and the air conditioning load power does not exceed the contracted power (first operating condition) (S61).

[0049] Control unit 21 calculates a first total amount of power (first total energy consumption) α for the total operating time during the prediction period under the first operating condition based on the outside air temperature, room temperature, the chiller output value during residual heat operation, and the COP matrix (S62). More specifically, control unit 21 references the COP matrix to calculate a COP value for each time period during residual heat operation and full-scale operation that corresponds to the combination of the outside air temperature, room temperature, and the chiller output value during residual heat operation. Control unit 21 calculates the first total amount of power α using the calculated COP value and the total operating time during the prediction operation period.

[0050] (Calculation of second total power amount β under second operating condition (with discharge assistance of storage battery 40 and without use of residual heat operation)) The control unit 21 calculates the output and total operating time (full-scale operating time) of the chiller 30 when residual heat operation is not performed and discharge assistance is performed from the storage battery 40 within the range where the total power of the general load power and the air conditioning load power does not exceed the contracted power (second operating condition) (S71).

[0051] Control unit 21 calculates a second total amount of power (second total energy consumption) β for the total operating time during the prediction period under the second operating condition based on the outside air temperature, room temperature, the chiller output value during discharge assistance, and the COP matrix (S72). More specifically, control unit 21 references the COP matrix to calculate a COP value for each time period during full-scale operation that corresponds to the combination of the outside air temperature, room temperature, and the chiller output value during discharge assistance. Control unit 21 calculates the second total amount of power β using the calculated COP value and the total operating time during the prediction operating period.

[0052] (Selection of operating conditions) The control unit 21 compares the first total amount of power α with the second total amount of power β.

[0053] If the second total amount of electric power β is smaller than the first total amount of electric power α (S80: YES), the control unit 21 operates the chiller 30 using discharge assistance from the storage battery 40 without performing residual heat operation (S51).

[0054] On the other hand, if the second COP value is equal to or greater than the first COP value (S80: NO), the control unit 21 does not assist discharge from the storage battery 40, and performs preheat operation of the chiller 30 (S52).

[0055] By performing such control, the air conditioning system 10 can prevent the power consumption per unit time from exceeding a preset threshold (contracted power), and can achieve efficient air conditioning using the chiller 30 while taking into account the total amount of power.

[0056] In addition, even in control based on total power consumption, as with the control based on the COP value described above, by taking into account the stored power of the storage battery, the air conditioning system 10 can prevent the power consumption per unit time from exceeding a preset threshold (contracted power) and more reliably achieve efficient air conditioning using the chiller 30.

[0057] Although the above description has been given taking the case of cooling as an example, the air conditioning system 10 can also achieve the same effects in the case of heating.

[0058] <1> A chiller that uses circulating water to exchange heat, a plurality of air conditioners to which the circulating water discharged from the chiller is supplied; a storage battery that assists in providing the power required to operate the chiller; a system control device that controls operation of the chiller, operation of the plurality of air conditioners, and charging and discharging of the storage battery; An air conditioning system comprising: The system control device Based on the operating environment including the outside temperature and the room temperature and the COP matrix of the chiller, a first COP value under a first operating condition in which the chiller is operated without receiving assistance from stored power from the storage battery so that power consumption per unit time does not exceed a preset threshold; and a second COP value under a second operating condition in which the chiller is operated for a period shorter than the first operating condition with assistance from the stored power from the storage battery so as not to exceed the threshold; an air conditioning system that operates the chiller under the second operating condition if the second COP value is higher than the first COP value.

[0059] <2> The system control device calculating a first total amount of electric energy α from the start of the chiller until the set room temperature is reached under the first operating condition; Calculating a second total amount of electric energy β from the start of the chiller until the set room temperature is reached under the second operating condition; If the second total amount of electric power β is smaller than the first total amount of electric power α, the chiller is operated under the second operating condition. <1> Air conditioning system.

[0060] <3> The system control device When the chiller is stopped for a predetermined period of time, control is performed to charge the storage battery to a predetermined SOC or higher. <1> or <2> Air conditioning system.

[0061] <4> a temperature sensor for measuring the temperature of the circulating water returning to the chiller; the system control device acquires the room temperature based on the temperature of the circulating water measured by the temperature sensor. <1> ~ <3> Any of the air conditioning systems. [Explanation of symbols]

[0062] 10:Air conditioning system 20: System control device 21: Control unit 22: Power supply control unit 30: Chiller 31: Heat exchanger 32: Expansion valve 33: Heat sink 35: Accumulator 36: Compressor 37: Pump 40: Storage battery 51, 52, 53, 54, 55: Indoor unit 90: Building 91, 92, 93, 94, 95: Living room 341, 342: Three-way valve 500:Plumbing

Claims

1. A chiller that uses circulating water to exchange heat, a plurality of air conditioners to which the circulating water discharged from the chiller is supplied; a storage battery that assists in providing the power required to operate the chiller; a system control device that controls operation of the chiller, operation of the plurality of air conditioners, and charging and discharging of the storage battery; An air conditioning system comprising: The system control device Based on the operating environment including the outside temperature and the room temperature and the COP matrix of the chiller, a first COP value under a first operating condition in which the chiller is operated without receiving assistance from stored power from the storage battery so that power consumption per unit time does not exceed a preset threshold; and a second COP value under a second operating condition in which the chiller is operated for a period shorter than the first operating condition with assistance from the stored power from the storage battery so as not to exceed the threshold; If the second COP value is higher than the first COP value, the chiller is operated under the second operating condition. Air conditioning system.

2. The system control device calculating a first total amount of electric energy α from the start of the chiller until the set room temperature is reached under the first operating condition; calculating a second total amount of electric energy β from the start of the chiller until the set room temperature is reached under the second operating condition; If the second total amount of electric power β is smaller than the first total amount of electric power α, the chiller is operated under the second operating condition. The air conditioning system of claim 1 .

3. The system control device When the chiller is stopped for a predetermined period of time, Control is performed to charge the storage battery to a predetermined SOC or higher. The air conditioning system according to claim 1 or 2.

4. a temperature sensor for measuring the temperature of the circulating water returning to the chiller; The system control device The room temperature is acquired based on the temperature of the circulating water measured by the temperature sensor. The air conditioning system according to claim 1 or 2.

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