WO2021205535A1

WO2021205535A1 - Refrigeration cycle device

Info

Publication number: WO2021205535A1
Application number: PCT/JP2020/015649
Authority: WO
Inventors: 正紘伊藤
Original assignee: 三菱電機株式会社
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2021-10-14
Also published as: JPWO2021205535A1; JP7258230B2

Abstract

A refrigeration cycle device (1) comprises a plurality of refrigeration cycle units (200-1 to 200-n) each of which has a mutually independent refrigerant circuit that uses a refrigerant, the refrigeration cycle units (200-1 to 200-n) being positioned in a circulation path of a shared heat medium and controlling the temperature of the heat medium. A control device (100) sets the number of operating units to an initial number of operating units at a first time at which the refrigeration cycle device (1) has started a cooling operation. The control device (100) determines an intermediate target change amount for the temperature of the heat medium at a second time on the basis of the difference between the temperature of the heat medium at the first time and a target temperature. The control device (100) adjusts the number of operating units among the plurality of refrigeration cycle units in accordance with the difference between the intermediate target change amount and a temperature change amount of the heat medium arising from the first time to the second time so that the temperature of the heat medium at a third time approaches the target temperature.

Description

Refrigeration cycle equipment

This disclosure relates to a refrigeration cycle device.

Conventionally, there is known an indirect air conditioner that generates cold water or hot water by a heat source machine such as a heat pump and conveys it to an indoor unit by a water pump and piping to cool and heat the room.

Since such an indirect air conditioner uses water or brine as a heat medium on the user side, it has been attracting attention in recent years in order to reduce the amount of refrigerant used.

Japanese Patent Application Laid-Open No. 06-307726 describes a plurality of chilled water supply modules that supply chilled water cooled by an evaporator, a temperature sensor that detects the temperature of chilled water supplied from the chilled water supply module, and outputs of the temperature sensors. Cold water supply including a controller including a manual setting means for controlling the number of chilled water supply modules and controlling the capacity of the refrigerating cycle of each chilled water supply module and setting the number of operating chilled water supply modules at the time of starting the device in advance. The device is disclosed.

Japanese Unexamined Patent Publication No. 06-307726

In Japanese Patent Application Laid-Open No. 06-307726, the number of chilled water supply modules in operation is adjusted, but if the number of chilled water supply modules to be started is not set, after starting all the chilled water supply modules, Since the number of vehicles in operation will be reduced, there will be a period of excessive number of vehicles in operation, and there is room for improvement. In addition, since the number of operating units is changed one by one, it may take time to reach the optimum number.

The apparatus of the present disclosure is made to solve the above-mentioned problems, and in a refrigeration cycle apparatus having a plurality of refrigeration cycle units for controlling the temperature of a heat medium such as water or brine, an excessive number of operating units and It is an object of the present invention to provide a refrigeration cycle apparatus capable of setting the temperature of the heat medium to the target temperature accurately at the target time while avoiding the above.

The refrigeration cycle apparatus of the present disclosure includes a plurality of refrigeration cycle units each having independent refrigerant circuits using a refrigerant, arranged in a common heat medium circulation path, and controlling the temperature of the heat medium, and a heat medium. It is provided with a temperature sensor that detects the temperature of the heat medium in the circulation path of the above and a control device that controls the number of operating units of a plurality of refrigeration cycle units.

The control device sets the number of operating units to the initial number of operating units at the first time when the refrigerating cycle device starts the cooling operation or the heating operation.

The control device determines the intermediate target change amount of the temperature of the heat medium at the second time after the first time based on the difference between the temperature of the heat medium detected by the temperature sensor at the first time and the target temperature. do.

The control device generates heat from the first time to the second time detected by the temperature sensor so that the temperature of the heat medium detected by the temperature sensor approaches the target temperature at the third time after the second time. The number of operating units is adjusted according to the difference between the amount of change in the temperature of the medium and the amount of change in the intermediate target.

According to the refrigeration cycle apparatus of the present disclosure, the temperature of the heat medium can be set to the target temperature accurately at the target time while avoiding the number of operating refrigeration cycle units becoming excessive.

It is a figure which shows the structure of the refrigerating cycle apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the control device which controls an air conditioner, and the remote control which controls a control device remotely. It is a figure for demonstrating the occurrence of thermo-off at the time of starting a refrigerating cycle apparatus. It is a flowchart for demonstrating the operation number determination process which the control device 100 executes in Embodiment 1. FIG. It is a figure which shows the adjustment example of the number of units when the cooling operation is executed in Embodiment 1. FIG. It is a figure which shows the adjustment example of the number of units when the heating operation is executed in Embodiment 1. FIG. It is a flowchart for demonstrating the operation number determination process which the control device 100 executes in Embodiment 2. It is a figure which shows the adjustment example of the number of units when the cooling operation is executed in Embodiment 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but it is planned from the beginning of the application that the configurations described in the respective embodiments are appropriately combined. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

Embodiment 1.
FIG. 1 is a diagram showing a configuration of a refrigeration cycle device according to the first embodiment. With reference to FIG. 1, the refrigeration cycle device 1 includes a heat source machine 2, a load device 3, pipes 4 and 5, a pump 6, and a temperature sensor 8. The heat source machine 2 includes a control device 100 and n units (n is an integer of 2 or more) of refrigeration cycle units 200-1 to 200-n. When n = 2, the heat source machine 2 includes a first refrigeration cycle unit 200-1 and a second refrigeration cycle unit 200-2.

Refrigerant circulation paths are formed in each of the first refrigeration cycle unit 200-1 and the second refrigeration cycle unit 200-2. Further, the heat medium is circulated between the heat source machine 2 and the load device 3 by the pipes 4 and 5 and the pump 6. The temperature sensor 8 detects the temperature of the heat medium passing through the pipe 4. In the following description, water will be illustrated as a heat medium. The heat medium may be brine or the like. Further, for the sake of simplicity, the temperature of the heat medium may be described as the water temperature.

The first refrigeration cycle unit 200-1, the second refrigeration cycle unit 200-2, ... The nth refrigeration cycle unit 200-n is connected in series with the water circulation path so that both act as a heat source or a cold heat source for water. It is composed of.

The first refrigeration cycle unit 200-1 includes a compressor 11, a four-way valve 12, a heat exchanger 13, a fan 14, an electronic expansion valve 15, and a heat exchanger 16. The second refrigeration cycle unit 200-2 includes a compressor 21, a four-way valve 22, a heat exchanger 23, a fan 24, an electronic expansion valve 25, and a heat exchanger 26.

Compressors

11 and 21 compress the refrigerant. The

compressors

11 and 21 are inverter-controlled by each control unit, and the operating frequency is variable. The

heat exchangers

13 and 23 exchange heat between the refrigerant and the outside air blown by the

fans

14 and 24. The

heat exchangers

16 and 26 exchange heat between the refrigerant and water. As the

heat exchangers

16 and 26, for example, plate heat exchangers can be used.

FIG. 1 shows a case where the four-

way valves

12 and 22 are set to perform heating. In this case, the first refrigeration cycle unit 200-1 and the second refrigeration cycle unit 200-2 act as heat sources. If the four-

way valves

12 and 22 are switched to reverse the circulation direction of the refrigerant, cooling or defrosting is performed, and the first refrigeration cycle unit 200-1 and the second refrigeration cycle unit 200-2 act as cold heat sources. do.

Since the refrigeration cycle unit 200-n has the same configuration as the refrigeration cycle units 200-1 and 200-2, the description will not be repeated.

The heat source machine 2 and the load device 3 are connected by pipes 4 and 5 for circulating water. The load device 3 includes an indoor unit 30, an indoor unit 40, and an indoor unit 50. The

indoor units

30, 40, and 50 are connected between the pipe 4 and the pipe 5 in parallel with each other.

The indoor unit 30 includes a heat exchanger 31, a fan 32 for sending indoor air to the heat exchanger 31, and a flow rate adjusting valve 33 for adjusting the flow rate of water. The heat exchanger 31 exchanges heat between water and indoor air.

The indoor unit 40 includes a heat exchanger 41, a fan 42 for sending indoor air to the heat exchanger 41, and a flow rate adjusting valve 43 for adjusting the flow rate of water. The heat exchanger 41 exchanges heat between water and indoor air.

The indoor unit 50 includes a heat exchanger 51, a fan 52 for sending indoor air to the heat exchanger 51, and a flow rate adjusting valve 53 for adjusting the flow rate of water. The heat exchanger 51 exchanges heat between water and indoor air.

Water is provided by the pump 6, n heat exchangers including

heat exchangers

16 and 26 connected in series, and heat exchangers 31, heat exchangers 41, and heat exchangers 51 connected in parallel to each other. A water circuit is formed using. Further, in the present embodiment, an air conditioner having two refrigeration cycle units and three indoor units is taken as an example. However, the number of indoor units may be three or more, or one.

The control units 7-1 to 7-n distributed and arranged in the refrigeration cycle units 200-1 to 200-n operate in cooperation with the control device 100. The control device 100 has

compressors

11 and 21, four-

way valves

12, 22 and fans 14 through control units 7-1 to 7-n according to settings from a remote controller or the like (not shown) and outputs of pressure sensors and temperature sensors. 24. Controls the

electronic expansion valves

15 and 25.

Further, the load device 3 includes control units 34, 44, 54 corresponding to the

indoor units

30, 40, 50, respectively. The control units 34, 44, 54 control the flow

rate adjusting valves

33, 43, 53 and the

fans

32, 42, 52, respectively.

Note that any one of the control units 7-1, 7-2, 34, 44, 54 may perform control as the control device 100. In that case, the control device 100 has

compressors

11, 21, four-

way valves

12, 22,

fans

14, 24,

electronic expansion valves

15, 25, pumps 6, and flow rate adjusting valves 33, based on data detected by other control units. 43, 53 and

fans

32, 42, 52 may be controlled.

FIG. 2 is a diagram showing a configuration of a control device that controls an air conditioner and a remote controller that remotely controls the control device. With reference to FIG. 2, the remote controller 300 includes an input device 301, a processor 302, and a transmitter 303. The input device 301 includes a push button for the user to switch ON / OFF of the indoor unit, a button for inputting a set temperature, and the like. The transmission device 303 is for communicating with the control device 100. The processor 302 controls the transmission device 303 according to the input signal given by the input device 301.

The control device 100 includes a receiving device 101 that receives a signal from the remote controller, a processor 102, and a memory 103.

The memory 103 includes, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash memory. The flash memory stores the operating system, application programs, and various types of data.

The processor 102 controls the overall operation of the refrigeration cycle device 1. The control device 100 shown in FIG. 1 is realized by the processor 102 executing the operating system and the application program stored in the memory 103. When executing the application program, various data stored in the memory 103 are referred to. The receiving device 101 is for communicating with the remote controller 300. When there are a plurality of indoor units, the receiving device 101 is provided in each of the plurality of indoor units.

When the control device is divided into a plurality of control units as shown in FIG. 1, each of the plurality of control units includes a processor. In such a case, a plurality of processors cooperate to perform overall control of the refrigeration cycle device 1.

FIG. 3 is a diagram for explaining the occurrence of thermo-off when the refrigeration cycle device is started. In FIG. 3, the time is shown on the horizontal axis, and the water temperature, the total frequency of the compressor, and the number of operating units are shown in order from the top.

When the refrigeration cycle device 1 is started to perform cooling under the connection installation condition in which a plurality of refrigeration cycle units are connected in series as shown in FIG. 1, a predetermined number of the total refrigeration cycle units are operated at time t51. And the water temperature begins to drop. An example in which the predetermined number of units is one is shown in FIG.

From time t51 to t52, one refrigeration cycle unit is in operation and the other refrigeration cycle unit is stopped. The refrigeration cycle unit that starts operation gradually increases the operating frequency from 0. If the compressor is suddenly turned at the upper limit frequency fmax per unit, when the refrigerant accumulated in the compressor is discharged at the start of operation, the refrigerating machine oil is also discharged from the compressor, and the compressor subsequently becomes insufficiently lubricated. This is because there is a risk of falling. Therefore, it is necessary to gradually increase the frequency at the start of operation of the compressor. Increasing the operating frequency increases the ability of the refrigeration cycle unit to cool the heat medium.

At time t52, if the target water temperature is not reached even if the compressor frequency of the refrigerating cycle unit during operation is maximized, the water temperature is brought to reach the target water temperature by additionally starting the refrigerating cycle unit. In the example of FIG. 3, since the water temperature T52 is still higher than the target water temperature at the time t52, the operation of two more units is added, and the number of operating refrigeration cycle units in operation is three at the time t52 to t53.

Two of the three units in operation gradually increase the operating frequency of the compressor from 0 after the time t52 at the start of operation. The total capacity of the three refrigeration cycle devices to cool the heat medium is determined by the total operating frequencies of the three compressors.

At time t53, the water temperature dropped to the target water temperature and the thermo-off state was established. After time t53, the number of operating units became zero and the total operating frequency of the compressor became zero.

With such a start-up method, the number of refrigerating cycle units in operation is not increased until the compressor frequency of the refrigerating cycle unit that first started operation is maximized, so it takes time to reach the target water temperature. In addition, the number of units to be additionally activated is determined in advance to two without considering the change in water temperature up to that point. As a result, after time t52, it is fixed to three-unit operation. Therefore, the number of units in operation becomes excessive, and thermo-off occurs due to excessive cooling at time t53. When the compressor is stopped due to thermo-off, the water temperature rises sharply. Such fluctuations in water temperature impair user comfort during cooling.

Therefore, in the present embodiment, the control device 100 determines the number of operating refrigeration cycle units to be additionally activated by looking at the difference between the water temperature detected by the temperature sensor 8 and the target water temperature at time t52.

FIG. 4 is a flowchart for explaining the operation number determination process executed by the control device 100 in the first embodiment. When the control device 100 receives a start command from a remote controller or the like, or when the refrigeration cycle device 1 is started (YES in S1), such as when the start time set by the timer is reached, the refrigeration cycle is performed in step S2. Set the number of units in operation to the initial number of units in operation. The initial number of operating units may be any number as long as it is a part of n refrigeration cycle units, but in the examples after FIG. 5, a case of one unit is shown.

If it is not at the time of startup (NO in S1), the control device determines whether or not the elapsed time from the time of startup is ΔTP1. When the elapsed time is ΔTP1 (YES in S3), the control device 100 calculates the required number of units N in step S4. Then, in step S5, the control device 100 adjusts the number of operating refrigeration cycle units so that the number of operating units is N.

When the elapsed time is not ΔTP1 (NO in S3), that is, before the elapsed time reaches ΔTP1 from the start-up and when the elapsed time is longer than ΔTP1, the control device 100 is the refrigerating cycle unit currently in operation. Maintain the number of operating units.

FIG. 5 is a diagram showing an example of adjusting the number of units when the cooling operation is executed in the first embodiment. FIG. 5 shows the total frequency Σf of the operating frequencies of the compressor, the water temperature Tw (t), and the number of operating refrigeration cycle units from the top.

In the middle water temperature, the target water temperature TwO and the intermediate target water temperature TwmO (t), which is the target water temperature at each time in the process of reaching the target water temperature, are shown in addition to the water temperature Tw (t). For the sake of simplicity, the water temperatures Tw (t1), Tw (t2), and Tw (t3) at each time t1, t2, t3 are described as Tw1, Tw2, Tw3, respectively.

With reference to FIGS. 1 and 5, each of the refrigeration cycle devices 1 has a plurality of independent refrigerant circuits that use a refrigerant, are arranged in a common heat medium circulation path, and control the temperature of the heat medium. The refrigeration cycle unit 200-1 to 200-n of the above is provided. The refrigeration cycle device 1 further includes a temperature sensor 8 that detects the temperature of the heat medium in the heat medium circulation path, and a control device 100 that controls the number of operating units of the plurality of refrigeration cycle units 200-1 to 200-n. ..

The control device 100 sets the number of operating units to the initial number of operating units at the first time t1 when the refrigerating cycle device 1 starts the cooling operation. In the example of FIG. 5, the initial number of operating units is one.

The control device 100 determines the temperature of the heat medium at the second time t2 after the first time t1 based on the difference between the temperature Tw1 of the heat medium detected by the temperature sensor 8 at the first time t1 and the target temperature TwO. The intermediate target change amount ΔTmO (= Tw2-TwmoO) of Tw is determined.

In the control device 100, the first time t1 detected by the temperature sensor 8 so that the temperature Tw3 of the heat medium detected by the temperature sensor 8 approaches the target temperature TwO at the third time t3 after the second time t2. The number of operating units is adjusted according to the difference between the temperature change amount ΔT (= Tw1-Tw2) of the heat medium generated from the second time to t2 and the intermediate target change amount ΔTmO.

The control device 100 determines the number of operating units of the refrigeration cycle unit to be changed at the second time t2 based on the difference between the temperature change amount ΔT and the intermediate target change amount ΔTmO.

The control device 100 determines whether or not the refrigeration cycle unit can be additionally activated based on the following equation (1). When the current water temperature Tw2 is higher than the target temperature TwmO (t) corresponding to the elapsed time obtained from the difference between the target water temperature TwO at the target time t3 and the pre-start water temperature Tw1, the control device 100 freezes. Judge that additional start of the cycle unit is possible. The target temperature TwmO (t) is indicated by a broken straight line in FIG.
Tw2> (TwO-Tw1) / (t3-t1) × (t2-t1) + Tw1 ... (1)
In other words, the following relationship can be said. The temperature sensor 8 detects the first temperature Tw1 at the first time t1 and detects the second temperature Tw2 at the second time t2 when the first time ΔTP1 has elapsed from the first time t1.

The control device 100 calculates the magnitude | Tw2-Tw1 | of the amount of temperature change ΔT of the heat medium generated from the first time t1 to the second time t2 at the second time t2. When the magnitude | Tw2-Tw1 | of the temperature change amount ΔT is smaller than the intermediate target change amount ΔTmO (indicated by the arrow A1), the control device 100 increases the number of operating units from the initial operating number.

Note that in FIG. 5, the case of | Tw2-Tw1 | <ΔTmO is shown, and the water temperature Tw2 is located above Twmo (t2) shown by a straight line.

More preferably, when the magnitude | Tw2-Tw1 | of the temperature change amount ΔT is larger than the intermediate target change amount ΔTmO (indicated by the arrow B1), the number of operating units is set to be larger than the initial operating number, if possible. Also reduce. In the example shown in FIG. 5, an example of increasing the number of operating units is shown, but in the case of | Tw2-Tw1 |> ΔTmO, the water temperature Tw2 is located below TwmO (t2) indicated by a straight line. .. Further, in the example of FIG. 5, since the initial number of operating units is one, the number of operating units cannot be reduced, but when the initial number of operating units is set to a plurality of units, the number of operating units can be reduced. ..

More preferably, the intermediate target change amount ΔTmO is the second case where the temperature of the heat medium changes with a constant temperature gradient from the first temperature Tw1 to the target temperature TwO from the first time t1 to the third time t3. It is the amount of change in the temperature of the heat medium from the first temperature Tw1 up to the temperature TwO (t2) of the heat medium at time t2.

The above relationship is derived from FIG. The amount of temperature change of the heat medium (water) from time t1 to t2 is indicated by (Tw2-Tw1). It is considered that this change is due to the energy used in the compressor at times t1 to t2. The energy used in the compressor at times t1 to t2 is considered to be proportional to the integrated value of the operating frequency of the compressor.

The amount of temperature change of the heat medium (water) from time t2 to t3 is indicated by (Tw3-Tw2). It is considered that this change is due to the energy used in the compressor at times t2 to t3. It is considered that the energy used in the compressor at times t2 to t3 is proportional to the integrated value of the operating frequency of the compressor. Then, the following relationship is established.
(Tw2-Tw1): ∫f (t1 to t2) = (Tw3-Tw2): ∫f (t2 to t3) ... (2)
In the equation (2), ∫f (t1 to t2) indicates the integrated value of the frequency f from the time t1 to the time t2. ∫f (t2 to t3) indicates the integrated value of the frequency f from the time t2 to the time t3.

By transforming the equation (2), the following equation (3) is obtained.
∫f (t2 to t3) = ∫f (t1 to t2) × (Tw3-Tw2) / (Tw2-Tw1)… (3)
Further, assuming that the average value of the compressor frequencies at times t2 to t3 is fave, there is a relationship of the following equation (4).
fave = ∫f (t2 to t3) / (t3-t2) ... (4)
Here, the number of refrigeration cycle units to be operated after time t2 can be calculated based on the following equations (5) and (6).
N = fave / fm ... (5)
The following equation (6) is derived from the equations (3), (4) and (5).
N = ∫f (t1 to t2) × (Tw3-Tw2) / (Tw2-Tw1) / (t3-t2) / fm… (6)
However, since N is an integer, the numbers after the decimal point are rounded up.

That is, the integral value ∫f (t2 to t3) of the total value of the compressor frequencies of the starting units required to change the water temperature by the target water temperature difference (= Tw3-Tw2) is averaged over time. By dividing this average value by the maximum frequency fm of one unit, the number of units N required to reach the target water temperature TwO at the target time t3 can be obtained.

FIG. 6 is a diagram showing an example of adjusting the number of units when the heating operation is executed in the first embodiment. FIG. 6 shows the total frequency Σf of the operating frequencies of the compressor, the water temperature Tw (t), and the number of operating refrigeration cycle units from the top.

In the middle water temperature, the target water temperature TwO and the intermediate target water temperature TwmO (t), which is the target water temperature at each time in the process of reaching the target water temperature, are shown in addition to the water temperature Tw (t). For the sake of simplicity, the water temperatures Tw (t11), Tw (t12), and Tw (t13) at each time t11, t12, and t13 are described as Tw11, Tw12, and Tw13, respectively.

With reference to FIGS. 1 and 6, the control device 100 sets the number of operating units to the initial number of operating units at the first time t11 when the refrigerating cycle device 1 starts the heating operation. In the example of FIG. 6, the initial number of operating units is one.

The control device 100 determines the temperature of the heat medium at the second time t12 after the first time t11 based on the difference between the temperature Tw11 of the heat medium detected by the temperature sensor 8 at the first time t11 and the target temperature TwO. The intermediate target change amount ΔTmO of is determined.

In the control device 100, the first time t11 detected by the temperature sensor 8 so that the temperature Tw of the heat medium detected by the temperature sensor 8 approaches the target temperature TwO at the third time t13 after the second time t12. The number of operating units is adjusted according to the difference between the temperature change amount ΔT (= Tw11-Tw12) of the heat medium generated from the second time to t12 and the intermediate target change amount ΔTmO.

The control device 100 determines the number of changed units of the refrigerating cycle unit in operation at the second time t12 based on the difference between the temperature change amount ΔT (= Tw11-Tw12) and the intermediate target change amount ΔTmO shown in FIG.

The control device 100 determines whether or not the refrigeration cycle unit can be additionally started based on the following equation (7). When the current water temperature Tw12 is lower than the target temperature TwmO (t) corresponding to the elapsed time obtained from the difference between the target water temperature TwO at the target time t13 and the pre-startup water temperature Tw11, the control device 100 freezes. Judge that additional start of the cycle unit is possible. The target temperature TwmO (t) is indicated by a broken straight line in FIG.
Tw12 <(TwO-Tw11) / (t13-t11) × (t12-t11) + Tw11… (7)
The temperature sensor 8 detects the first temperature Tw11 at the first time t11, and detects the second temperature Tw12 at the second time t12 when the first time ΔTP1 has elapsed from the first time t11.

When the magnitude | Tw12-Tw11 | of the temperature change amount ΔT is smaller than the intermediate target change amount ΔTmO (indicated by the arrow A2), the control device 100 increases the number of operating units from the initial operating number.

Note that, in FIG. 6, the case of | Tw12-Tw11 | <ΔTmO is shown, and the water temperature Tw12 is located below Twmo (t2) shown by a straight line.

More preferably, the control device 100 operates when the magnitude | Tw12-Tw11 | of the temperature change amount ΔT is larger than the intermediate target change amount ΔTmO (indicated by the arrow B2), if possible. Is reduced from the initial number of units in operation. In the example shown in FIG. 6, an example of increasing the number of operating units is shown, but in the case of | Tw2-Tw1 |> ΔTmO, the water temperature Tw12 is located above TwmO (t2) indicated by a straight line. .. Further, in the example of FIG. 6, since the initial number of operating units is one, the number of operating units cannot be reduced, but when the initial number of operating units is set to a plurality of units, the number of operating units can be reduced. ..

More preferably, the intermediate target change amount ΔTmO is the second case where the temperature of the heat medium changes with a constant temperature gradient from the first temperature Tw11 to the target temperature TwO from the first time t11 to the third time t13. It is the amount of change in the temperature of the heat medium from the first temperature Tw11 up to the temperature TwO (t12) of the heat medium at time t12.

The above relationship is derived from FIG. The amount of temperature change of the heat medium (water) from time t11 to t12 is indicated by (Tw12-Tw11). It is considered that this change is due to the energy used in the compressor at times t11 to t12. It is considered that the energy used in the compressor at times t11 to t12 is proportional to the integrated value of the operating frequency of the compressor.

The amount of temperature change of the heat medium (water) from time t12 to t13 is indicated by (Tw13-Tw12). It is considered that this change is due to the energy used in the compressor at times t2 to t3. It is considered that the energy used in the compressor at times t12 to t13 is proportional to the integrated value of the operating frequency of the compressor. Then, the following relationship is established.
(Tw12-Tw11): ∫f (t11 to t12) = (Tw13-Tw12): ∫f (t12 to t13) ... (8)
In the formula (8), ∫f (t11 to t12) indicates the integrated value of the frequency f from the time t1 to the time t2. ∫f (t12 to t13) indicates the integrated value of the frequency f from the time t2 to the time t3.

By transforming the equation (8), the following equation (9) is obtained.
∫f (t12 to t13) = ∫f (t11 to t12) × (Tw13-Tw12) / (Tw12-Tw11)… (9)
Further, assuming that the average value of the compressor frequencies at times t12 to t13 is fave, there is a relationship of the following equation (10).
fave = ∫f (t12 to t13) / (t13-t12) ... (10)
Here, the number of refrigeration cycle units to be operated after time t12 can be calculated based on the following equations (11) and (12).
N = fave / fm ... (11)
The following equation (12) is derived from the equations (9), (10) and (11).
N = ∫f (t11 to t12) × (Tw13-Tw12) / (Tw12-Tw11) / (t13-t12) / fm… (12)
However, since N is an integer, the numbers after the decimal point are rounded up.

That is, the integral value ∫f (t12 to t13) of the total value of the compressor frequencies of the starting units required to change the water temperature by the target water temperature difference (= Tw13-Tw12) is averaged over time. By dividing this average value by the maximum frequency fm of one unit, the number of units N required to reach the target water temperature TwO at the target time t13 can be obtained.

As described above, in the first embodiment, in order to bring the temperature of the heat medium to the target temperature at the target time, the refrigerating cycle device determines the suitability of the number of operating units once at the intermediate time, and the number of operating units is excessive. If there is a shortage, adjust the number of units in operation. For this reason, it is possible to avoid the temperature fluctuation of the heat medium due to the thermo-off occurring in the middle due to the excess capacity while avoiding the non-achievement of the target temperature due to the insufficient capacity.

Embodiment 2.
In the first embodiment, an example in which the number of operating units is reviewed once by the target time has been described. As a result, the number of operating units can be adjusted by reflecting the state of the load device, and the occurrence of thermo-off can be suppressed. In the second embodiment, the first adjustment is executed in the same manner, but an example in which the adjustment of the number of operating units is executed thereafter will be described. Since the configuration of the refrigeration cycle device of the second embodiment is the same as the configuration shown in FIG. 1, the description will not be repeated.

FIG. 7 is a flowchart for explaining the operation number determination process executed by the control device 100 in the second embodiment. In the flowchart of FIG. 7, the processes of steps S6 to S8 are added to the flowchart of FIG. 4 showing the process of the first embodiment. Since the processes of steps S1 to S5 have been described with reference to FIG. 4, the description will not be repeated here.

If the elapsed time does not match ΔTP1 in step S3 (NO in S3), the control device 100 determines in step S6 whether the elapsed time is longer than ΔTP1. When the elapsed time> ΔTP1 (YES in S6), the control device 100 determines whether or not the water temperature has reached the target temperature TwO even once in step S7.

If the water temperature has reached the target temperature TwO even once (YES in S7), the control device 100 proceeds to step S8 to complete the adjustment of the number of operating refrigeration cycle devices. In this case, after this timing, the operation until the target time is executed with the fixed number of units for which the adjustment has been completed.

On the other hand, when the water temperature has never reached the target temperature TwO (NO in S7), the control device 100 proceeds to step S4, recalculates the required number of units N, and in step S5, N. Adjust the number of units in operation so that the refrigeration cycle unit of the unit is in operation.

In step S6, if the elapsed time has not yet reached ΔTP2 (NO in S6), the number of operating units is not adjusted, and the operating state of the refrigeration cycle device is maintained with the initial number of operating units.

FIG. 8 is a diagram showing an example of adjusting the number of units when the cooling operation is executed in the second embodiment. FIG. 8 shows the total frequency Σf of the operating frequencies of the compressor, the water temperature Tw (t), and the number of operating refrigeration cycle units from the top.

In the middle water temperature, the target water temperature TwO and the intermediate target water temperature TwmO (t), which is the target water temperature at each time in the process of reaching the target water temperature, are shown in addition to the water temperature Tw (t). For the sake of simplicity, the water temperatures Tw (t21) to Tw (t25) at each time t21 to t25 are described as Tw21 to Tw25, respectively.

The control device 100 sets the number of operating units to the initial number of operating units at the first time t21 when the refrigerating cycle device 1 starts the cooling operation. In the example of FIG. 8, the initial number of operating units is one.

The control device 100 determines the temperature of the heat medium at the second time t22 after the first time based on the difference between the temperature Tw21 of the heat medium detected by the temperature sensor 8 at the first time t21 and the target temperature TwO. The intermediate target change amount ΔTmO is determined.

The control device 100 has the first time t21 detected by the temperature sensor 8 so that the temperature Tw of the heat medium detected by the temperature sensor 8 approaches the target temperature TwO at the third time t25 after the second time t22. The number of operating units is adjusted according to the difference between the temperature change amount ΔT (= Tw21-Tw22) of the heat medium generated from the second time to t22 and the intermediate target change amount ΔTmO.

The control device 100 determines the number of operating units of the refrigeration cycle unit to be changed at the second time t22 based on the difference between the temperature change amount ΔT (= Tw21-Tw22) and the intermediate target change amount ΔTmO. In this case as well, the number of changed units is determined by the same method as in the case of FIG.

In other words, the following relationships can be said. The temperature sensor 8 detects the first temperature Tw21 at the first time t21, and detects the second temperature Tw22 at the second time t22 when the first time ΔTP1 has elapsed from the first time t21. When the magnitude | Tw22-Tw21 | of the temperature change amount ΔT is smaller than the intermediate target change amount ΔTmO, the control device 100 increases the number of operating units from the initial operating number.

Note that in FIG. 8, the case of ΔT = | Tw22-Tw21 | <ΔTmO is shown, and the water temperature Tw22 is located above Twmo (t22) shown by a straight line.

More preferably, as shown in FIG. 8, the control device 100 calculates the intermediate target change amount TwO (t23) corresponding to the intermediate time t23 at the intermediate time t23 between the second time t22 and the third time t25. Then, the number of operating units is adjusted based on the calculated intermediate target change amount ΔTmO (t23) and the temperature Tw23 of the heat medium at the intermediate time t23. At this time, the intermediate target water temperature TwmO indicated by the broken line is updated, and when the point is indicated by (time, water temperature) on the graph, it is changed to the broken line connecting (t22, Tw22) and (t25, TwO). Will be done.

Note that in FIG. 8, the case of ΔT = | Tw23-Tw22 | <ΔTmO (t23) is shown, and the water temperature Tw23 is located above Twmo (t23) shown by a straight line. As a result, the control device 100 increases the number of refrigerating cycle units in operation from two to three at time t23.

Also, at time t24, which is the next update time, the intermediate target water temperature Twmo indicated by the broken line is updated, and when the points are indicated by (time, water temperature) on the graph, (t23, Tw23) and (t25, It is changed to a broken straight line connecting TwO). In FIG. 8, since ΔT = | Tw24-Tw23 | = ΔTmO (t24), the number of units is fixed to 3 thereafter.

In addition, in FIG. 5, FIG. 6, and FIG. 8, an example in which the number of operating units is changed one by one is shown, but according to the present embodiment, the cooling load or the heating load is large, and the times t2, t12, t22. When the difference between the temperature change amount ΔT and the intermediate target change amount ΔTmO is widened, the number of units increased is further increased according to the difference, and the amount of increase in the number of operating units changes to two or more.

The water temperature change occurs when the difference between the cooling capacity or heating capacity of the heat source machine and the water side load is given to the water. Whether or not the target water temperature is reached in the target time cannot be known unless these complicated calorific value balances are solved. However, in the first and second embodiments, the required number of units can be calculated by indirectly considering the calorific value balance by using the integrated value of the water temperature change amount and the compressor frequency total value.

In the first and second embodiments, since the number of activated refrigeration cycle units required to reach the target water temperature in the target time is known, it is possible to bring the water temperature closer to the target water temperature in the target time. In addition, the number of additional units that can be started can be set to an appropriate number, preventing excessive cooling of water and ensuring comfort.

In the configuration shown in FIG. 1, the heat source machine 2, the load device 3, the pump 6, and the temperature sensor 8 are separated, but the

heat exchangers

16 and 26 of the heat source machine 2 are separated. It may be used as a repeater together with the pump 6 and the temperature sensor 8. Further, the main part of the control device 100 may be arranged in either the heat source machine 2 or the load device 3. Further, although the example in which the heat medium is water has been described, the heat medium may be any other material as long as it is a medium that carries heat. For example, brine may be used instead of water.

The embodiments disclosed this time should be considered to be exemplary in all respects and not restrictive. The scope of the present invention is shown by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 refrigeration cycle device, 2 heat source machine, 3 load device, 4, 5 piping, 6 pump, 7, 34, 44, 54 control unit, 8 temperature sensor, 11,21 compressor, 12, 22 four-way valve, 13, 16 , 23,26,31,41,51 Heat exchanger, 14,24,32,42,52 Fan, 15,25 Electronic expansion valve, 30,40,50 Indoor unit, 33,43,53 Flow control valve, 100 Control device, 101 receiver, 102, 302 processor, 103 memory, 200-1 to 200-n refrigeration cycle unit, 300 remote controller, 301 input device, 303 transmitter.

Claims

It is a refrigeration cycle device
A plurality of refrigeration cycle units each having independent refrigerant circuits using a refrigerant, arranged in a common heat medium circulation path, and controlling the temperature of the heat medium, and a plurality of refrigeration cycle units.
A temperature sensor that detects the temperature of the heat medium in the circulation path of the heat medium, and
A control device for controlling the number of operating units of the plurality of refrigeration cycle units is provided.
The control device sets the number of operating units to the initial number of operating units at the first time when the refrigerating cycle device starts the cooling operation or the heating operation.
The control device determines the temperature of the heat medium at the second time after the first time based on the difference between the temperature of the heat medium detected by the temperature sensor at the first time and the target temperature. Determine the amount of change in the intermediate target
The control device starts from the first time detected by the temperature sensor so that the temperature of the heat medium detected by the temperature sensor approaches the target temperature at the third time after the second time. A refrigeration cycle device that adjusts the number of operating units according to the difference between the amount of change in temperature of the heat medium and the amount of change in the intermediate target generated by the second time.
The refrigeration cycle device according to claim 1, wherein the control device determines the number of changed units of the number of operating units at the second time based on the difference between the amount of temperature change and the amount of intermediate target change.
The refrigerating cycle device according to claim 2, wherein the control device increases the number of operating units to the initial operating number when the magnitude of the temperature change amount is smaller than the intermediate target change amount.
The refrigeration cycle device according to claim 3, wherein the control device reduces the number of operating units to be smaller than the initial operating number when the magnitude of the temperature change amount is larger than the intermediate target change amount.
The temperature sensor detects the first temperature at the first time and
The intermediate target change amount is the second time when the temperature of the heat medium changes with a constant temperature gradient from the first temperature to the target temperature during the period from the first time to the third time. The refrigeration cycle apparatus according to claim 1, wherein the temperature of the heat medium is the amount of change from the first temperature up to the temperature of the heat medium.
The control device calculates an intermediate target change amount corresponding to the intermediate time at an intermediate time between the second time and the third time, and the calculated intermediate target change amount and the heat medium at the intermediate time. The refrigeration cycle apparatus according to claim 1, wherein the number of operating units is adjusted based on the temperature of the above.