JP6989788B2 - Refrigeration cycle device - Google Patents

Description

Regarding refrigeration cycle equipment.

A water-cooled air-conditioning device that cools (or heats) a heat exchanger on the heat source side using water is known as an air-conditioning device that uses a refrigerant to harmonize indoor air. Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-75948) discloses that in a water-cooled air conditioner, the supply flow rate of cooling water is adjusted so that the high pressure of the refrigerant circuit becomes the optimum pressure.

In a water-cooled refrigeration cycle device, if the temperature of the cooling water is low during cooling operation (when the heat exchanger on the user side is operated as an evaporator), the high-pressure pressure of the refrigerant circuit drops and the water goes to the indoor side. There was a problem that the liquid refrigerant could not be sufficiently circulated.

The refrigeration cycle device of the first aspect controls the compressor, the heat exchanger on the user side, the first electric valve, the heat exchanger on the heat source side, the second electric valve, the bypass circuit, and the third electric valve. It has a part. The compressor compresses the refrigerant. The first motorized valve regulates the flow rate of the refrigerant to the heat exchanger on the user side. The heat source side heat exchanger exchanges heat between the refrigerant and water. The second electric valve is located on the downstream side of the heat source side heat exchanger when the user side heat exchanger is operated as an evaporator, and adjusts the flow rate of the refrigerant. The bypass circuit connects the discharge side of the compressor and between the first motorized valve and the second motorized valve. The third motorized valve regulates the flow rate of the refrigerant in the bypass circuit. The control unit determines whether the first condition is satisfied when the user-side heat exchanger is operated as an evaporator, and when the first condition is satisfied, the third electric valve is opened to a predetermined opening degree R1. The first condition includes the condition A that the opening degree of the first motorized valve exceeds the predetermined opening degree P1.

Since the refrigeration cycle device of the first aspect controls the flow rate of the bypass circuit by the opening degree of the first solenoid valve, the pressure on the downstream side of the second solenoid valve when the user-side heat exchanger is operated as an evaporator. Is secured, and the circulation amount of the liquid refrigerant to the indoor side is secured.

The refrigeration cycle device of the second aspect is the device of the first aspect, and the first condition corresponds to the pressure on the downstream side of the second electric valve when the heat exchanger on the utilization side is further operated as an evaporator. The condition B that the value is equal to or less than a predetermined value is included. Here, the pressure equivalent value is, for example, pressure or temperature.

Since the refrigeration cycle device of the second aspect includes the condition that the pressure equivalent value on the downstream side of the second solenoid valve is equal to or less than the predetermined value as the condition for opening the opening degree of the third solenoid valve on the bypass circuit by a predetermined opening degree. The refrigerant pressure on the downstream side of the second solenoid valve is surely secured.

The refrigeration cycle device of the third aspect is the device of the second aspect, and the first condition is that the supercooling of the downstream side of the second motorized valve is further performed when the heat exchanger on the utilization side is operated as an evaporator. The condition C that the degree is equal to or more than a predetermined value is included.

In the refrigeration cycle device of the third aspect, the degree of supercooling is secured, the refrigerant between the first electric valve and the second electric valve is in a gas-liquid two-phase state, and the pressure loss increases, so that the refrigerant pressure decreases. However, it prevents the liquid refrigerant from being sufficiently circulated to the indoor side.

The refrigeration cycle device according to the fourth aspect is any of the devices from the first aspect to the third aspect, and the control unit determines whether or not the first condition and the second condition are satisfied, and the first condition is satisfied, but the first condition is satisfied. When it is determined that the two conditions are not satisfied, the third solenoid valve is opened by a predetermined opening R1, and when it is determined that the first condition and the second condition are satisfied, the third solenoid valve is opened at a predetermined opening larger than the predetermined opening R1. Open up to R2. The second condition is a condition in which the opening degree of the first solenoid valve exceeds the predetermined opening degree P2, which is larger than the predetermined opening degree P1.

The refrigeration cycle device of the fourth aspect is the first bypass circuit when it is estimated that the pressure on the downstream side of the second electric valve is further reduced when the heat exchanger on the utilization side is operated as an evaporator. 3 Since the opening degree of the electric valve is opened wider, the pressure on the downstream side of the second electric valve is recovered when the heat exchanger on the utilization side is operated as an evaporator more quickly.

The refrigeration cycle device according to the fifth aspect is any of the devices from the first aspect to the fourth aspect, and after the control unit satisfies the first condition and opens the third motorized valve to a predetermined opening degree R1, When the first condition is satisfied after the lapse of the predetermined time T1, the third motorized valve is further opened by the predetermined opening r3.

The refrigeration cycle device of the fifth aspect adjusts the opening degree of the third solenoid valve of the bypass circuit, and after a predetermined time elapses, further adjusts the opening degree of the third solenoid valve, so that the third solenoid valve is more appropriate. The opening of the valve can be controlled.

The refrigerating cycle device of the sixth aspect is the device of the fifth aspect, and the control unit satisfies the first condition, opens the third motorized valve by a predetermined opening degree R1, and then elapses a predetermined time T1. If it is determined whether or not the first condition and the second condition are satisfied, and if it is determined that the first condition is satisfied but the second condition is not satisfied, the third solenoid valve is further opened by a predetermined opening r3, and the first condition and the second condition are described. When it is determined that the condition is satisfied, the third solenoid valve is further opened by a predetermined opening r4 larger than the predetermined opening r3. The second condition is a condition in which the opening degree of the first solenoid valve exceeds the predetermined opening degree P2, which is larger than the predetermined opening degree P1.

The refrigeration cycle device of the sixth aspect is the first bypass circuit when it is estimated that the pressure on the downstream side of the second electric valve is further reduced when the heat exchanger on the utilization side is operated as an evaporator. 3 Since the opening degree of the electric valve is opened wider, the pressure on the downstream side of the second electric valve is recovered when the heat exchanger on the utilization side is operated as an evaporator more quickly.

The refrigerating cycle device according to the seventh aspect is any of the devices from the first aspect to the sixth aspect, and the control unit satisfies the first condition, opens the third motorized valve by a predetermined opening degree R1, and then determines the predetermined value. When the third condition is satisfied after the lapse of time T1, the opening degree of the third solenoid valve is reduced by a predetermined opening degree r5. The third condition is a condition in which the opening degree of the first solenoid valve is smaller than the predetermined opening degree P1 and is equal to or less than the predetermined opening degree P3.

The refrigeration cycle apparatus according to the seventh aspect can prevent the pressure on the downstream side of the second motorized valve from rising too much when the heat exchanger on the utilization side is operated as an evaporator.

The refrigeration cycle device according to the eighth aspect is any of the devices from the first aspect to the seventh aspect, and the control unit controls the pressure of the heat source side heat exchanger when the user side heat exchanger is operated as an evaporator. The opening degree of the second electric valve is controlled to the predetermined opening degree Q1 so that the equivalent value becomes the value corresponding to the first predetermined pressure. Further, when the third solenoid valve is closed or the opening degree of the third solenoid valve is not changed for the third predetermined time or more after the lapse of the predetermined time T2, the control unit further opens the second solenoid valve. Is controlled to a predetermined opening Q2 larger than the predetermined opening Q1. Here, the pressure equivalent value is, for example, pressure or temperature.

The refrigeration cycle device of the eighth aspect increases the opening degree of the second solenoid valve when the state of the third solenoid valve is stable, so that the high pressure pressure is reduced and the power consumption of the compressor is reduced. Can be done.

It is a figure which shows the whole structure of the refrigerating cycle apparatus 1 of 1st Embodiment. It is a flowchart which shows the flow of opening degree control of the 3rd electric valve 28 (bypass electric valve) in the refrigeration cycle apparatus 1 of 1st Embodiment. It is a flowchart which shows the flow of the target condensation pressure control by the 2nd electric valve 24 (heat source side expansion valve) in the refrigerating cycle apparatus 1 of 1st Embodiment. It is a flowchart which shows the characteristic part of the flow of opening degree control of the 3rd solenoid valve 28 (bypass solenoid valve) in the refrigerating cycle apparatus 1 of the modification 1F.

<First Embodiment>
(1) Configuration of Refrigerating Cycle Device 1 FIG. 1 shows an outline of the overall configuration of the refrigerating cycle device 1 of the first embodiment. FIG. 1 mainly describes the refrigerant circuit 2. The refrigeration cycle device 1 can be used for an air conditioner for heating and cooling, a water cooler and a water heater, and the like. The refrigeration cycle device 1 is a water-cooled type. The refrigerant flowing through the refrigerant circuit 2 exchanges heat with the water flowing through the water circuit 5 in the heat source side heat exchanger 23.

The refrigeration cycle device 1 of the present embodiment includes a heat source unit 20, utilization units 30a and 30b, and a control unit 40. The utilization units 30a and 30b are one or a plurality of units. In FIG. 1, two utilization units 30a and 30b are exemplified.

The heat source unit 20 includes a compressor 21, an accumulator 26, a four-way switching valve 22, a heat source side heat exchanger 23, a second electric valve 24, a high pressure receiver 25, a bypass circuit 27, and a third electric valve 28. A plurality of temperature sensors 12 to 17, a pressure sensor 18, a liquid side closing valve 61, and a gas side closing valve 62 are included. In the heat source unit 20, the four-way switching valve 22, the heat source side heat exchanger 23, the second electric valve 24, the high pressure receiver 25, and the liquid side closing valve 61 are connected in order by a refrigerant pipe. The refrigerant pipe between the second motorized valve 24 and the liquid side closing valve 61 may be referred to as a liquid pipe 29.

The compressor 21 compresses the refrigerant. The four-way switching valve 22 switches the flow of the refrigerant between the broken line (heating) and the solid line (cooling) in FIG. The heat source side heat exchanger 23 exchanges heat between the refrigerant flowing through the refrigerant circuit 2 and the water flowing through the water circuit 5. The heat source side heat exchanger 23 is a plate type heat exchanger. The second electric valve 24 adjusts the flow rate of the refrigerant flowing through the refrigerant pipe. The high-pressure receiver 25 and the accumulator 26 temporarily store the refrigerant.

The pressure sensor 18 is connected to the discharge side of the compressor 21 and measures high pressure. The temperature sensor 14 is arranged in the refrigerant pipe on the four-way switching valve 22 side of the heat source side heat exchanger 23, and measures the inlet temperature of the refrigerant pipe of the heat source side heat exchanger 23. The temperature sensor 15 is arranged in the refrigerant pipe on the second electric valve 24 side of the heat source side heat exchanger 23, and measures the outlet temperature of the refrigerant pipe of the heat source side heat exchanger 23. The temperature sensor 16 is arranged on the heat source side heat exchanger 23 and measures the refrigerant temperature in the gas-liquid two-phase state. The temperature sensor 17 is arranged on the liquid pipe 29 and measures the temperature of the refrigerant pipe.

The bypass circuit 27 connects the refrigerant pipe on the discharge side of the compressor 21 and the refrigerant pipe (liquid pipe 29) between the second electric valve 24 and the high pressure receiver 25. The third solenoid valve 28 (bypass solenoid valve) is arranged on the bypass circuit 27. The opening degree of the third motorized valve 28 can be changed continuously or stepwise from closed to fully open. By changing the opening degree of the third motorized valve 28, the flow rate of the refrigerant flowing through the bypass circuit 27 changes. The bypass circuit 27 supplies the high-pressure refrigerant on the discharge side of the compressor 21 to the liquid pipe 29 when the pressure of the liquid pipe 29 drops during the cooling operation (when the heat exchanger on the user side is operated as an evaporator). However, it has a role of maintaining the pressure of the liquid pipe 29. The bypass circuit 27 is connected to the refrigerant pipe between the second electric valve 24 and the high-pressure receiver 25 from the refrigerant pipe on the discharge side of the compressor 21, but is not limited to this, and is used with the second electric valve 24. It suffices if it is connected to the refrigerant pipe between the units 30a and 30b and the liquid side closing valve 61. Further, the high-pressure refrigerant discharged from the compressor 21 may be configured to be supplied between the second solenoid valve 24 and the first solenoid valves 31a and 31b described later.

The utilization unit 30a includes a utilization side heat exchanger 32a and a first motorized valve 31a. The utilization unit 30b includes a utilization side heat exchanger 32b and a first motorized valve 31b. The first electric valves 31a, 31b and the user side heat exchangers 32a, 32b are connected by a refrigerant pipe, and the first electric valves 31a, 31b are connected to the liquid side closing valve 61 by the refrigerant pipe, and the user side heat exchanger 32a. , 32b are refrigerant pipes connected to the gas side closing valve 62.

The first motorized valves 31a and 31b reduce the pressure of the refrigerant and adjust the flow rate of the refrigerant. The user-side heat exchangers 32a and 32b exchange heat between the refrigerant and the indoor air.

The control unit 40 is a computer. The control unit 40 has a processor and a memory. In the present embodiment, the control unit 40 is arranged in the heat source unit 20. The control unit 40 may be arranged at another position. The control unit 40 may be composed of a plurality of computers, and the plurality of computers may be arranged at different positions to perform control in cooperation with each other. The control unit 40 controls each device in the heat source unit 20, the utilization units 30a, and 30b. The control unit 40 is connected to the heat source unit 20, each device in the utilization units 30a and 30b, and the temperature sensors 12 to 17. The control unit 40 obtains information such as the operating state of each device and the measured value of each sensor, and controls each device based on the information.

During the heating operation, the refrigerant discharged from the compressor 21 includes the heat exchangers 32a and 32b on the user side, the first motorized valves 31a and 31b, the high pressure receiver 25, the second motorized valve 24, the heat exchanger on the heat source side 23, and the accumulator 26. Via, it is sucked into the compressor 21 again. In other words, during heating, the user-side heat exchangers 32a and 32b function as a condenser (radiator), and the heat source-side heat exchanger 23 functions as an evaporator.

During the cooling operation, the refrigerant discharged from the compressor 21 includes the heat source side heat exchanger 23, the second electric valve 24, the high pressure receiver 25, the first electric valves 31a and 31b, the user side heat exchangers 32a and 32b, and the accumulator 26. Via, it is sucked into the compressor 21 again. In other words, during cooling, the heat source side heat exchanger 23 functions as a condenser (radiator), and the user side heat exchangers 32a and 32b function as an evaporator.

(2) Configuration of Water Circuit 5 As described above, the refrigerant of the refrigeration cycle device 1 exchanges heat with water in the heat source side heat exchanger 23. This water circulates in the water circuit 5. In the water circuit 5, a heat source side heat exchanger 23, a water amount adjusting valve 11, a circulation pump 51, and a water heat source (not shown) are connected by a water pipe. A first temperature sensor 12 and a second temperature sensor 13 are arranged on the water pipe. The first temperature sensor 12 is located outside the heat source unit 20 and on the water pipe at the inlet of the heat source side heat exchanger 23. The second temperature sensor 13 is located outside the heat source unit 20 and on the water pipe at the outlet of the heat source side heat exchanger 23. The first temperature sensor 12 and the second temperature sensor 13 are not limited to the above-mentioned positions, and are arranged on the water pipe at the inlet and the water pipe at the outlet of the heat source side heat exchanger 23 in the heat source unit 20, respectively. May be good.

The circulation pump 51 circulates water in the water circuit 5. The rotation speed of the circulation pump 51 is controlled so that the differential pressure between the inlet and the outlet of the pump is within a predetermined range. In the present embodiment, the rotation speed of the circulation pump 51 is controlled independently of the control unit 40. In FIG. 1, the circulation pump 51 is connected to the outlet side of the heat source side heat exchanger 23 of the water circuit 5. The circulation pump 51 may be connected to the inlet side of the heat source side heat exchanger 23 of the water circuit 5, or may be at another position as long as it is arranged in the water circuit 5.

The water amount adjusting valve 11 adjusts the amount of water flowing in the water circuit 5. The water amount adjusting valve 11 is an electric valve whose opening degree can be adjusted. The water amount adjusting valve 11 is controlled by the control unit 40. The amount of water in the water circuit 5 is primitively determined by the rotation speed of the circulation pump 51, but since the circulation pump 51 cannot be controlled by the control unit 40, the control unit 40 uses the water amount adjusting valve 11 to control the amount of water in the water circuit 5. Control. When the amount of water in the water circuit 5 changes due to the control of the water amount adjusting valve 11, a differential pressure is generated at the inlet and outlet of the circulation pump 51. The circulation pump 51 controls the circulation amount of water in the water circuit 5 based on the generated differential pressure. In FIG. 1, the water amount adjusting valve 11 is connected to the inlet side of the heat source side heat exchanger 23 of the water circuit 5. The water amount adjusting valve 11 may be connected to the outlet side of the heat source side heat exchanger 23 of the water circuit 5, or may be at another position as long as it is arranged in the water circuit 5.

The water heat source cools the water flowing through the water circuit 5, and is, for example, a cooling tower.

The first temperature sensor 12 measures the temperature of the water pipe at the inlet of the heat source side heat exchanger 23. The second temperature sensor 13 measures the temperature of the water pipe at the outlet of the heat source side heat exchanger 23. The first temperature sensor 12 and the second temperature sensor 13 are thermistors. The measured values of the temperatures measured by the first temperature sensor 12 and the second temperature sensor 13 are sent to the control unit 40.

The control unit 40 of the refrigeration cycle device 1 adjusts the opening degree of the water amount adjusting valve 11 based on the measured values of the temperatures measured by the first temperature sensor 12 and the second temperature sensor 13 and other information.

(3) Opening Control of the Third Solenoid Valve 28 (Bypass Solenoid Valve) The opening control of the third solenoid valve 28 of the present embodiment will be described with reference to the flowchart of FIG.

The bypass circuit 27 and the third motorized valve 28 of the present embodiment do not necessarily have to be used depending on the operating conditions of the refrigerating cycle device 1. In other words, the third motorized valve 28 may be in the closed state. The case where the refrigerant flows through the bypass circuit 27 is, for example, the temperature of the cooling water flowing through the water circuit 5 during the cooling operation of the refrigerating cycle device, in other words, when the heat source side heat exchanger 23 is used as a condenser. If it is too low. In such a case, the pressure of the liquid pipe 29 may decrease, and the amount of refrigerant circulating to the utilization units 30a and 30b may be insufficient. At this time, it is necessary to open the third solenoid valve 28 to allow the refrigerant to flow through the bypass circuit 27 to maintain the pressure of the refrigerant in the liquid pipe 29.

First, the control unit 40 confirms the opening degree of the third motorized valve 28 (S101). Since this control is a control that starts in the closed state of the third solenoid valve 28, the process proceeds to step 102 after confirming the closed state of the third solenoid valve 28.

In step 102, the control unit 40 determines whether or not the first condition is satisfied.

In the present embodiment, the first condition includes three conditions A to C.

Condition A is a condition that the opening degree of the first solenoid valves 31a and 31b exceeds the predetermined opening degree P1. In the present embodiment and the modified example, when a plurality of first solenoid valves 31a and 31b are present, the opening degree of the first solenoid valve is the opening degree of the first solenoid valve having the largest opening degree. Condition A is a condition indicating that the amount of refrigerant circulating to the utilization units 30a and 30b is insufficient.

Condition B is a condition that the pressure equivalent value of the liquid pipe 29 is equal to or less than a predetermined value. Here, the pressure equivalent value is, for example, pressure or temperature.

Condition C is a condition that the degree of supercooling of the liquid pipe 29 is equal to or higher than a predetermined value.

In step 102, if any one of the conditions A to C is not satisfied, the control unit 40 determines that the first condition is not satisfied, and proceeds to step S111. In step S111, the control unit 40 waits for the elapse of the predetermined time T4, and then returns to step S102 again.

In step 102, when all three conditions A to C are satisfied, the control unit 40 proceeds to step S103, assuming that the first condition is satisfied.

When the first condition is satisfied in step S102, the control unit 40 opens the opening degree of the third solenoid valve 28 to the predetermined opening degree R1 and allows the refrigerant to flow through the bypass circuit 27 (S103).

Next, in step S104, the control unit 40 waits for the elapse of the predetermined time T1 while holding the opening degree of the third motorized valve 28 at the predetermined opening degree R1.

After the elapse of the predetermined time T1, the control unit 40 again determines whether or not the first condition is satisfied (S105). Then, when the first condition is satisfied, the control unit 40 determines whether or not the second condition is satisfied (S106). The second condition consists of three conditions, conditions A', B, and C. Conditions B and C are the same as the first condition. The condition A'is a condition that the opening degree of the first solenoid valves 31a and 31b exceeds the predetermined opening degree P2 (P2> P1) larger than the predetermined opening degree P1. In other words, the second condition is a condition indicating that the amount of refrigerant circulating to the utilization units 30a and 30b is insufficient more than the condition A. If the first condition is satisfied but the second condition is not satisfied in step S106, the process proceeds to step S122, and the control unit 40 further opens the opening degree of the third motorized valve 28 by a predetermined opening degree r3. When the first condition is satisfied in step S106 and the second condition is also satisfied, the process proceeds to step S121, and the control unit 40 increases the opening degree of the third solenoid valve 28 to a predetermined opening degree r4 (which is larger than the predetermined opening degree r3). Open only r4> r3).

If the first condition is not satisfied in step S105, the process proceeds to step S107 to determine whether or not the third condition is satisfied. The third condition is that the opening degree of the first solenoid valves 31a and 31b is smaller than the predetermined opening degree R3 (R3 <R1). If the control unit 40 determines in step S107 that the first condition is not satisfied and the third condition is not satisfied, the process proceeds to step S124 and the opening degree of the third motorized valve 28 is maintained as it is. If the control unit 40 determines in step S107 that the first condition is not satisfied and the third condition is satisfied, the process proceeds to step S123 and the opening degree of the third solenoid valve 28 is reduced by a predetermined opening degree r5. In this case, the control unit 40 determines that the amount of refrigerant circulating to the utilization units 30a and 30b is sufficient, and controls to reduce the amount of refrigerant flowing through the bypass circuit 27.

In other words, in the present embodiment, when the first condition is satisfied in step S102, the control unit 40 opens the opening degree of the third solenoid valve 28 to the predetermined opening degree R1 (S103), and then the predetermined time T1. After the lapse (S104), in steps S105 to S107, the opening degree of the third motorized valve 28 is changed according to the determination of the first to third conditions. Further, after the elapse of the predetermined time T1 (S104), in steps S105 to S107, the control unit 40 determines the first to third conditions, repeats the operation of changing the opening degree of the third motorized valve 28, and repeats the operation of changing the opening degree of the third motorized valve 28. The opening degree of the motorized valve 28 may be appropriately maintained. By this control, the pressure of the refrigerant in the liquid pipe 29 can be maintained and the amount of refrigerant circulation can be secured.

(4) Opening control of the second electric valve 24 (heat source side expansion valve) Conventionally, the water-cooled refrigeration cycle device is predetermined during the cooling operation (when the user side heat exchanger is operated as an evaporator). The target condensation pressure was set and controlled so that the condensation pressure was constant. However, since the predetermined target condensation pressure is fixed, it is necessary to raise the condensation pressure to the target condensation pressure even under the condition that the condensation pressure may be low, and the power consumption of the compressor is insufficiently suppressed. Become.

Therefore, in the present embodiment, in order to suppress the power consumption, the refrigeration cycle device 1 is operated by changing the target condensation pressure equivalent value as necessary. Here, the pressure equivalent value is, for example, pressure or temperature. Hereinafter, the target condensation pressure equivalent value and the condensation pressure equivalent value are the target condensation pressure and the condensation pressure, respectively. The opening degree control of the second motorized valve 24 when the target condensation pressure is changed will be described with reference to FIG.

First, in step S201, the control unit 40 controls the opening degree of the second motorized valve 24 so that the condensing pressure becomes a predetermined target condensing pressure. Let Q1 be the opening degree of the second solenoid valve when the condensation pressure reaches a predetermined target condensation pressure.

Next, in step S202, the condensation pressure is kept constant for a predetermined time T2. Next, after the lapse of the predetermined time T2, in steps S203 and S204, the control unit 40 determines the state of the third solenoid valve 28 (bypass solenoid valve). In step S203, the control unit 40 determines whether or not the third motorized valve 28 is closed. When it is closed, the process proceeds to step S205. When the third motorized valve 28 is open, the process proceeds to step S204. In step S204, the control unit 40 confirms whether the opening degree of the third solenoid valve 28 has been changed by T3 or more for a predetermined time. When the change is made, the control unit 40 determines that the target condensation pressure is not changed, and returns to step S201.

When the control unit 40 determines in step S204 that the opening degree of the third solenoid valve 28 has not been changed by T3 or more for a predetermined time, the control unit 40 determines that the third solenoid valve 28 is closed in step S203, as in the case of determining that the third solenoid valve 28 is closed. Proceed to step S205.

In step S205, the control unit 40 lowers the target condensation pressure (equivalent value) by, for example, 1 ° C., and proceeds to step S206.

In step S206, the control unit 40 increases the opening degree of the second motorized valve 24 (heat source side expansion valve) from the predetermined opening degree Q1 to the predetermined opening degree Q2 (predetermined opening degree Q2) so as to reach the lowered target condensation pressure. Change to Q2> Q1). By such control, the refrigerating cycle device 1 determines whether or not the pressure of the liquid pipe 29 is stable based on the opening degree of the third electric valve 28, and if the pressure is stable, lowers the target condensation pressure. It is possible to reduce the power consumption of the compressor.

(5) Features (5-1)
The refrigerating cycle device 1 of the present embodiment has a configuration in which the refrigerant is cooled by using circulating water in the heat source side heat exchanger 23. The refrigeration cycle device 1 has a heat source unit 20 and utilization units 30a and 30b. The utilization units 30a and 30b include first motorized valves 31a and 31b and utilization side heat exchangers 32a and 32b. The heat source unit 20 has a bypass circuit 27 that bypasses the heat source side heat exchanger 23, and a third electric valve 28 that adjusts the refrigerant flow rate of the bypass circuit.

When the refrigeration cycle device 1 has a large number (for example, 5 or more) of utilization units, and the piping connecting the utilization unit and the heat source unit is long (for example, 20 m or more), the utilization unit is more than the heat source unit. Especially in the case where the refrigerant is placed at a high position (for example, 10 m or more), in the heat source unit that sends out the refrigerant, the refrigerant at a higher pressure offsets the pressure loss in the refrigerant pipe connecting the heat source unit and the utilization unit. Is required to be sent out.

More specifically, during the cooling operation of the refrigerating cycle device 1, if the temperature of the cooling water is too low, the pressure of the liquid pipe 29 may decrease, and the amount of refrigerant circulating to the utilization units 30a and 30b may be insufficient.

Therefore, in the present embodiment, the bypass circuit 27 is provided and the third electric valve 28 is opened to allow the refrigerant to flow through the bypass circuit 27 and maintain the pressure of the liquid pipe 29 to the utilization units 30a and 30b. Secure the amount of refrigerant circulation.

(5-2)
The control unit 40 of the refrigeration cycle device 1 of the present embodiment determines whether or not the first condition is satisfied (S102), and when the first condition is satisfied, the opening degree of the third motorized valve 28 is set to a predetermined opening degree R1. Only open (S103). The first condition includes the condition A that the opening degree of the first solenoid valves 31a and 31b exceeds the predetermined opening degree P1.

When the opening degree of the first motorized valves 31a and 31b exceeds the predetermined opening degree P1, it is considered that the circulation amount of the refrigerant to the utilization units 30a and 30b may be insufficient. Therefore, by opening the opening degree of the third motorized valve 28 by a predetermined opening degree R1, the pressure of the liquid pipe 29 can be maintained and the amount of refrigerant circulating to the utilization units 30a and 30b can be secured.

(5-3)
The first condition further includes the condition B that the pressure equivalent value of the liquid pipe 29 is a predetermined value or less when the user-side heat exchangers 32a and 32b are operated as an evaporator.

In this case as well, the pressure of the liquid pipe 29 may be insufficient, and the amount of refrigerant circulating to the utilization units 30a and 30b may be insufficient. Therefore, by opening the opening degree of the third motorized valve 28 by a predetermined opening degree R1, the pressure of the liquid pipe 29 is maintained and the amount of refrigerant circulating to the utilization units 30a and 30b is secured.

(5-4)
The first condition further includes the condition C that the degree of supercooling of the pressure of the liquid pipe 29 is equal to or higher than a predetermined value when the user-side heat exchangers 32a and 32b are operated as an evaporator.

If the degree of supercooling is insufficient, the refrigerant between the first solenoid valves 31a and 31b and the second solenoid valve 24 is in a gas-liquid two-phase state, and the pressure loss increases. As a result, the pressure of the liquid pipe 29 decreases, and the liquid refrigerant cannot be sufficiently circulated to the utilization units 30a and 30b. Therefore, the control unit 40 maintains the pressure of the liquid pipe 29 by opening the opening degree of the third solenoid valve by a predetermined opening degree R1, and secures the amount of refrigerant circulating to the utilization units 30a and 30b.

(5-5)
The control unit 40 of the refrigeration cycle device 1 of the present embodiment satisfies the first condition (S102), opens the third motorized valve 28 by a predetermined opening degree P1 (S103), and after a predetermined time T1 elapses (S104). Further, when the first condition is satisfied (S105), the third motorized valve 28 is further opened by a predetermined opening degree r3 (S122).

After the third motorized valve 28 is opened by a predetermined opening degree R1 (S103), if the pressure of the liquid pipe 29 is not sufficiently high or the pressure of the liquid pipe 29 is lowered, the control unit 40 is charged. The third motorized valve 28 is further opened from the predetermined opening degree R1 by the predetermined opening degree r3 (S122). As a result, the amount of high-pressure refrigerant supplied to the liquid pipe 29 through the bypass circuit 27 can be increased as compared with the case where the third motorized valve 28 has a predetermined opening R1 open, and the pressure of the liquid pipe 29 is further increased. be able to.

(5-6)
The control unit 40 of the refrigeration cycle device 1 of the present embodiment satisfies the first condition (S102), opens the third motorized valve 28 by a predetermined opening degree R1 (S103), and after a predetermined time T1 elapses (S104). In addition to the first condition (S105), the second condition (S106) is examined. The second condition is a condition in which the opening degree of the first solenoid valves 31a and 31b exceeds the predetermined opening degree P2 (P2> P1) larger than the predetermined opening degree P1. When it is determined that the first condition is satisfied but the second condition is not satisfied, the third solenoid valve 28 is further opened by a predetermined opening r3, and when it is determined that the first condition and the second condition are satisfied, the third solenoid valve 28 is opened. Is further opened by a predetermined opening r4 (r4> r3) larger than the predetermined opening r3.

The control unit 40 estimates the insufficient amount of refrigerant circulation to the utilization units 30a and 30b according to the opening degree of the first solenoid valve 31a and 31b, and determines the opening degree of the third solenoid valve 28 accordingly. ing.

(5-7)
The control unit 40 of the refrigeration cycle device 1 of the present embodiment satisfies the first condition (S102), opens the third motorized valve 28 by a predetermined opening degree R1 (S103), and after a predetermined time T1 elapses (S104). In addition, the third condition (S107) is examined together with the first condition. The third condition is that the opening degree of the first solenoid valves 31a and 31b is smaller than the predetermined opening degree P1 and is equal to or less than the predetermined opening degree P3. When it is determined that the first condition is not satisfied and the third condition is not satisfied, the opening degree of the third solenoid valve 28 is maintained (S124), and when it is determined that the first condition is not satisfied and the third condition is satisfied, the third condition is satisfied. The opening degree of the motorized valve 28 is closed by a predetermined opening degree r5.

When the control unit 40 determines that the opening degrees of the first solenoid valves 31a and 31b are narrow and there is no shortage of refrigerant circulation to the utilization units 30a and 30b, the control unit 40 tends to reduce the opening degree of the third solenoid valves 28. To control.

(5-8)
The refrigerating cycle device 1 of the present embodiment variably controls the target condensation pressure equivalent value according to the operating state of the refrigerating cycle when the user-side heat exchangers 32a and 32b are operated as evaporators. Here, the pressure equivalent value is, for example, pressure or temperature.

Specifically, the following control is performed.

First, the control unit 40 controls the opening degree of the second motorized valve 24 to a predetermined opening degree Q1 so that the condensing pressure becomes a predetermined target condensing pressure (S201). When the condensation pressure reaches the target condensation pressure, the control unit 40 waits for the elapse of T2 for a predetermined time (S202). Next, the control unit 40 determines whether or not the condition regarding the opening degree of the third solenoid valve 28 (bypass solenoid valve) satisfies a predetermined condition. The condition is that the third solenoid valve is closed (S203) or the opening degree of the third solenoid valve 28 has not changed by T3 or more for a predetermined time (S204). When this condition is satisfied, the control unit 40 lowers the target condensation pressure (S205), and increases the opening degree of the second electric valve 24 to a predetermined opening degree Q1 so that the target condensation pressure is lowered. It is widened to a predetermined opening degree Q2 (Q2> Q1) (S206).

The conditions of steps S203 and S204 are conditions indicating that the refrigerant is not flowing in the bypass circuit 27 or that the flow rate is stable even if the refrigerant is flowing, in other words, the pressure of the liquid pipe 29 is increased. It means that it is stable. In such a case, the control unit 40 can reduce the target condensation pressure and reduce the power consumption of the compressor.

(6) Modification example (6-1) Modification example 1A
In the first embodiment, the first conditions are three conditions A to C. The first condition may be more or less as appropriate.

In the modification 1A, the first condition is only the condition A. The configuration and control of the refrigerating cycle device of the modified example 1A are exactly the same as those of the first embodiment.

(6-2) Modification 1B
In the modification 1A, the first conditions are condition A and condition C. The configuration and control of the refrigerating cycle device of the modified example 1A are exactly the same as those of the first embodiment.

(6-3) Modification 1C
In the first embodiment, the second condition is condition A', condition B and condition C. The second condition may be more or less as appropriate.

In the modification 1C, the second condition is only the condition A'. The configuration and control of the refrigerating cycle device of the modified example 1C are exactly the same as those of the first embodiment.

(6-4) Modification 1D
In the first embodiment, the second condition is the condition A', the condition B and the condition C, and in the modified example 1C, the second condition is only the condition A'. In the modified example 1D, the second conditions are condition A'and condition C. The configuration and control of the refrigerating cycle device of the modified example 1D are exactly the same as those of the first embodiment.

(6-5) Modification 1E
In the first embodiment, after the predetermined time T1 has elapsed in step S104, the first condition to the third condition are determined in steps S105 to S107. In the modified example 1E, the steps up to step S104 are the same as those of the first embodiment, but next, the control unit 40 determines whether or not the first condition and the third condition are satisfied, and the first condition is satisfied. The difference is that the two conditions are not judged. Others are the same as those in the first embodiment.

(6-6) Modification 1F
The control flow of the third motorized valve 28 (bypass motorized valve) of the modified example 1F is almost the same as that of the first embodiment, but the parts of step S102 and step S103 are different. FIG. 4 shows a partial description of the control flow of the third solenoid valve 28 (bypass solenoid valve) of the modified example 1F, centering on a portion different from the first embodiment.

First, similarly to step S101 of the first embodiment, the control unit 40 confirms the closed state of the third motorized valve (S301). Next, the process proceeds to step S302, and similarly to step S102, the control unit 40 determines whether or not the first condition is satisfied.

In the modified example 1F, unlike the first embodiment, the control unit 40 determines whether or not the first condition is satisfied in step S302, and then subsequently determines whether or not the second condition also satisfies the condition (S303). The content of the second condition is the same as that of the first embodiment, and the conditions are A', B, and C. The condition A'is a condition that the opening degree of the first solenoid valves 31a and 31b exceeds the predetermined opening degree P2 (P2> P1) larger than the predetermined opening degree P1.

When the first condition is satisfied in step S303 but the second condition is not satisfied, the control unit 40 opens the opening degree of the third solenoid valve to the predetermined opening degree R1 (step S305). When the first condition is satisfied and the second condition is also satisfied in step S303, the control unit 40 opens the opening degree of the third solenoid valve to a predetermined opening degree R2 (R2> R1) larger than the predetermined opening degree R1 (. Step S304).

In the modified example 1F, the point that the elapse of the predetermined time T1 is waited for (S306), the first condition to the third condition are determined again, and the control is performed based on the first condition is exactly the same as in the first embodiment. be.

In the modified example 1F, the first condition may be only the condition A as in the modified example 1A, or may be the condition A and the condition C as in the modified example 1B. Further, the second condition may be only the condition A'as in the modified example 1C, or may be the condition A'and the condition C as in the modified example 1D.

(6-7) Modification 1G
In the first embodiment, there is only one heat source side heat exchanger 23. In order to increase the amount of heat exchange, a plurality of heat source side heat exchangers may be arranged. In the modification 1G, there are two heat source side heat exchangers 23. Correspondingly, two second solenoid valves 24 are also arranged. The other configurations of the refrigeration cycle device 1 are the same as those of the first embodiment. In the modification 1G, in the control of the two second motorized valves 24, the condensation pressure is controlled to be the target condensation pressure. Other controls are the same as in the first embodiment.

Although the embodiments of the present disclosure have been described above, it will be understood that various modifications of the embodiments and details are possible without departing from the spirit and scope of the present disclosure described in the claims. ..

1 ・ ・ ・ ・ ・ ・ ・ ・ Refrigeration cycle device 20 ・ ・ ・ ・ ・ ・ ・ ・ ・ Heat source unit 21 ・ ・ ・ ・ ・ ・ ・ ・ Compressor 23 ・ ・ ・ ・ ・ ・ ・ ・ Heat source side Heat exchanger 24 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 2nd electric valve (heat source side expansion valve)
27 ・ ・ ・ ・ ・ ・ ・ ・ ・ Bypass circuit 28 ・ ・ ・ ・ ・ ・ ・ ・ ・ 3rd motorized valve (bypass motorized valve)
30a, 30b ... Usage units 31a, 31b ... First motorized valves 32a, 32b ... Usage side heat exchanger 40 ... Control unit

Japanese Unexamined Patent Publication No. 2008-75948

Claims (8)

A compressor (21) that compresses the refrigerant,
User-side heat exchangers (32a, 32b) and
The first motorized valves (31a, 31b) for adjusting the flow rate of the refrigerant to the utilization side heat exchanger, and
A heat source side heat exchanger (23) that exchanges heat between the refrigerant and water,
A second electric valve (24) located on the downstream side of the heat source side heat exchanger and adjusting the flow rate of the refrigerant when the user side heat exchanger is operated as an evaporator.
When the user-side heat exchanger is operated as an evaporator, the refrigerant discharged by the compressor is not passed through the heat source-side heat exchanger, but is connected to the first electric valve and the second electric valve. Bypass flow path (27) to bypass the piping between
A third motorized valve (28) that adjusts the flow rate of the refrigerant in the bypass flow path,
When the user-side heat exchanger is operated as an evaporator, it is determined whether the first condition is satisfied, and when the first condition is satisfied, the third electric valve is opened to a predetermined opening degree R1. 40) and
Equipped with
The first condition includes a condition A in which the opening degree of the first solenoid valve exceeds a predetermined opening degree P1.
Refrigeration cycle equipment. The first condition further includes a condition B in which the pressure equivalent value on the downstream side of the second motorized valve is equal to or less than a predetermined value when the user-side heat exchanger is operated as an evaporator.
The refrigeration cycle apparatus according to claim 1. The first condition further includes a condition C that the degree of supercooling on the downstream side of the second motorized valve is equal to or higher than a predetermined value when the user-side heat exchanger is operated as an evaporator.
The refrigeration cycle apparatus according to claim 2. The control unit determines whether or not the first condition and the second condition are satisfied, and if it is determined that the first condition is satisfied but the second condition is not satisfied, the third motorized valve is set to the predetermined opening degree R1. When it is determined that the first condition and the second condition are satisfied, the third motorized valve is opened to a predetermined opening degree R2 larger than the predetermined opening degree R1.
The second condition is a condition in which the opening degree of the first solenoid valve exceeds the predetermined opening degree P2, which is larger than the predetermined opening degree P1.
The refrigeration cycle apparatus according to any one of claims 1 to 3. When the first condition is satisfied, the control unit further opens the third solenoid valve after the predetermined opening degree R1 is opened, the predetermined time T1 elapses, and the first condition is satisfied, the third solenoid valve is further opened. Open only the predetermined opening r3,
The refrigeration cycle apparatus according to any one of claims 1 to 4. The control unit determines whether or not the first condition and the second condition are satisfied after satisfying the first condition, opening the third motorized valve by the predetermined opening degree R1, and after elapse of the predetermined time T1. When it is determined that the first condition is satisfied but the second condition is not satisfied, the third motorized valve is further opened by the predetermined opening r3, and it is determined that the first condition and the second condition are satisfied. The third motorized valve is further opened with a predetermined opening degree r4 larger than the predetermined opening degree r3.
The second condition is a condition in which the opening degree of the first solenoid valve exceeds the predetermined opening degree P2, which is larger than the predetermined opening degree P1.
The refrigeration cycle apparatus according to claim 5. When the first condition is satisfied, the third motorized valve is opened by the predetermined opening degree R1, the predetermined time T1 elapses, and the third condition is satisfied, the control unit satisfies the third motorized valve. Decrease the opening by the predetermined opening r5,
The third condition is a condition in which the opening degree of the first solenoid valve is smaller than the predetermined opening degree P1 and is equal to or less than the predetermined opening degree P3.
The refrigeration cycle apparatus according to any one of claims 1 to 6. When the user-side heat exchanger is operated as an evaporator, the control unit opens the second electric valve so that the pressure equivalent value of the heat source-side heat exchanger becomes the first predetermined pressure equivalent value. Is controlled to the predetermined opening Q1
Further, when the third solenoid valve is closed or the opening degree of the third solenoid valve does not change for a predetermined time T3 or more after the lapse of the predetermined time T2, the opening degree of the second solenoid valve is predetermined. Controlled to a predetermined opening Q2 larger than the opening Q1.
The refrigeration cycle apparatus according to any one of claims 1 to 7.

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