JP2011174662A - Air heat source heat pump water heater/air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air heat source heat pump water heater/air conditioner minimizing deterioration of heating capacity by shortening restoration time back to a heating operation while avoiding freezing risks in a refrigerant/water heat exchanger during defrost operation. <P>SOLUTION: The air heat source heat pump water heater/air conditioner includes a defrost control part wherein, when a defrost condition with respect to a heat source side air heat exchanger is satisfied, in response to an outside air temperature and an inlet temperature of hot water circulated in the refrigerant/water heat exchanger, the defrost operation is carried out by any one of directly switching a refrigerant circuit to a cooling cycle to start the defrost operation (1); is switched to the cooling cycle to start the defrost operation after carrying out pump down operation of recovering a refrigerant in a receiver (2); and is started to restart the compressor after the pump down operation, temporarily stopping a compressor and switching to the cooling operation after a certain time (3). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air heat source heat pump hot water supply / air conditioner that performs hot water supply and / or air conditioning using an air heat source heat pump, and more particularly to a defrost thereof.

  The air heat source heat pump hot water supply / air conditioner includes an air heat source heat pump having a closed cycle refrigerant circuit in which the refrigerant discharged from the compressor is circulated through the heat source side air heat exchanger and the refrigerant / water heat exchanger, and the pump. The water thus circulated is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger to become hot water, and a hot water circulation circuit for circulating the hot water to the load side is provided. In this air heat source heat pump hot water supply / air conditioner, one of the heating cycle and the cooling cycle can be selected by switching the circulation direction of the refrigerant with a four-way switching valve provided in the refrigerant circuit. Therefore, by operating the refrigerant circuit by switching to the heating cycle, the water flowing in the hot water circulation circuit can be heated by the refrigerant / water heat exchanger functioning as a condenser to produce hot water. The hot water may be used for hot water supply, or may be used as a heat source for heating by being supplied to a use side heat exchanger.

  In such an air heat source heat pump hot water supply / air conditioner, if heating operation for producing hot water with a refrigerant / water heat exchanger is continued, frost is generated in the heat source side air heat exchanger functioning as an evaporator, particularly at low outside temperatures. Heat exchange efficiency decreases. For this reason, when frost formation on the heat source side air heat exchanger is detected, the refrigerant circuit is switched from the heating cycle to the cooling cycle to reverse the refrigerant circulation direction, and the frosted heat source side air heat exchanger functions as a condenser. By doing so, defrosting operation is performed in which frost is melted by heat radiation from the refrigerant.

  As a technique related to the defrost operation of a heat pump, for example, Patent Document 1 shows that when performing a defrost operation by a reverse cycle, a pump down operation is performed before and after that to prevent abnormal low pressure, a decrease in hydraulic pressure, or the like. Has been. Further, in Patent Document 2, a defrosting hot gas bypass circuit is provided for the refrigerant / water heat exchanger, and during defrost operation, the pump down operation is performed to store the refrigerant on the refrigerant / water heat exchanger side. There is shown a heat pump hot water supply apparatus in which hot gas is caused to flow through a hot gas bypass circuit to start defrosting operation and liquid back during defrosting is prevented.

  Patent Document 3 discloses that a defrost preparation operation for increasing the water temperature on the hot water flow path side of the refrigerant / water heat exchanger at the start of the defrost operation bypasses the hot water storage tank and supplies water to the refrigerant / water heat exchanger. A heat pump hot water supply apparatus provided with a bypass circuit that circulates water is shown. Further, in Patent Document 4, the refrigerant / water heat exchanger serves as an evaporator during the defrost operation in the reverse cycle method, and exhibits a negative ability to cool water with the refrigerant. Therefore, during the defrost operation, the refrigerant is supplied to the expansion valve. There is disclosed a heat pump hot water supply apparatus that bypasses the refrigerant / water heat exchanger from the upstream side and flows to the suction side of the compressor to reduce the minus capacity.

Japanese Patent Publication No. 8-27108 JP 2006-336930 A JP 2008-121923 A JP 2008-224088 A

  In the above-described air heat source heat pump hot water supply / air conditioner, when the refrigerant circuit is switched and the defrost operation is performed, if the temperature of the water circulating to the refrigerant / water heat exchanger and the outside air temperature are both low, the temporary low pressure at the start of the defrost operation There was a risk of the refrigerant / water heat exchanger freezing due to the drop, and an additional heat source had to be used to avoid this. However, in a system that does not have a hot water storage tank as a heat source, a heat source cannot be secured. Therefore, as shown in the above patent document, pump down operation, compressor stop / restart control, or additional defrosting is performed. The circuit is used to prepare for defrosting to avoid temporary drop in low pressure, but pump down operation, compressor stop / restart control, defrosting preparation operation, etc. are performed uniformly. As a result, there is a problem that the return time to the heating operation becomes longer and the heating capacity is lowered.

  The present invention has been made in view of such circumstances, and during defrost operation, while avoiding the risk of freezing in the refrigerant / water heat exchanger, the return time to the heating operation is shortened, and the heating capacity is improved. An object of the present invention is to provide an air heat source heat pump hot water supply / air conditioner capable of minimizing the decrease.

In order to solve the above problems, the air heat source heat pump hot water supply / air conditioner of the present invention employs the following means.
That is, in the air heat source heat pump hot water supply / air conditioning apparatus according to the present invention, the refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including the heat source side air heat exchanger and the refrigerant / water heat exchanger, and the refrigerant By reversing the circulation direction of the air, an air heat source heat pump in which one of a cooling cycle and a heating cycle can be selected, and water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger. A hot water circulation circuit that circulates the warm water to the load side, and performs a defrost operation of the heat source side air heat exchanger by switching the refrigerant circulation direction of the air heat source heat pump to the cooling cycle. In a heat source heat pump hot water supply / air conditioner, hot water circulated to the refrigerant / water heat exchanger when a defrost condition for the heat source side air heat exchanger is satisfied Depending on the inlet temperature and the outside temperature,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation.
(3) After the pump-down operation of (2) above, the compressor is once stopped, switched to the cooling cycle after a certain time, the compressor is restarted, and the defrost operation is started.
The defrost control part which performs a defrost driving | operation in any of these is provided.

  According to the present invention, when the heat source side air heat exchanger is frosted and the defrost condition is satisfied, according to the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger, (1) The defrosting operation is started by switching the refrigerant circuit to the cooling cycle as it is. (2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation. (3) After the pump-down operation of (2) above, the compressor is once stopped, switched to the cooling cycle after a certain time, the compressor is restarted, and the defrost operation is started. In accordance with the hot water inlet temperature and the outside air temperature, for example, the hot water inlet temperature and the outside air temperature are both higher than the set temperature, for example, A, the hot water inlet By dividing the temperature region where the temperature and the outside air temperature are lower than the set temperature into B, and the temperature region where the hot water inlet temperature and the outside air temperature are lower than the B region into regions such as C, in the A region, the pattern (1), B The defrosting operation can be performed in the area (2) in the area and the pattern (3) in the area C. Therefore, no matter which pattern is used for defrosting, the refrigerant / water heat exchanger can be prevented from temporarily lowering the low pressure, and the refrigerant / water heat exchanger can be frozen or the low pressure protection function can be activated. It is possible to avoid the defrost operation. In addition, the time for returning to the heating operation can be shortened and the deterioration of the heating capacity can be minimized as compared with the case where the pump down operation and the compressor stop / restart control are uniformly performed during the defrost operation.

Furthermore, in the air heat source heat pump hot water supply / air conditioning apparatus according to the present invention, the refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including a heat source side air heat exchanger and a refrigerant / water heat exchanger, and the refrigerant By reversing the circulation direction of the air, an air heat source heat pump in which one of a cooling cycle and a heating cycle can be selected, and water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger. A hot water circulation circuit that circulates the warm water to the load side, and performs a defrost operation of the heat source side air heat exchanger by switching the refrigerant circulation direction of the air heat source heat pump to the cooling cycle. In the heat source heat pump hot water supply / air conditioner, when defrost conditions for the heat source side air heat exchanger are satisfied, hot water circulated to the refrigerant / water heat exchanger In accordance with the mouth temperature and the outside temperature,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation.
The defrost control part which performs a defrost driving | operation in any of these is provided.

  According to the present invention, when the heat source side air heat exchanger is frosted and the defrost condition is satisfied, according to the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger, (1) The defrosting operation is started by switching the refrigerant circuit to the cooling cycle as it is. (2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation. In accordance with the hot water inlet temperature and the outside air temperature, for example, the hot water inlet temperature and the outside air temperature are both higher than the set temperature, for example, A, the hot water inlet By dividing the temperature region in which the temperature and the outside air temperature are equal to or lower than the set temperature into regions such as B, it is possible to perform the defrost operation with the pattern (1) in the A region and the pattern (2) in the B region. Therefore, no matter which pattern is used for defrosting, the refrigerant / water heat exchanger can be prevented from temporarily lowering the low pressure, and the refrigerant / water heat exchanger can be frozen or the low pressure protection function can be activated. The defrost operation can be performed while avoiding, and the return time to the heating operation can be shortened and the decrease in the heating capacity can be minimized as compared with the case where the pump down operation is uniformly performed during the defrost operation.

Furthermore, in the air heat source heat pump hot water supply / air conditioning apparatus according to the present invention, the refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including a heat source side air heat exchanger and a refrigerant / water heat exchanger, and the refrigerant By reversing the circulation direction of the air, an air heat source heat pump in which one of a cooling cycle and a heating cycle can be selected, and water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger. A hot water circulation circuit that circulates the hot water to the load side, and performs a defrost operation of the heat source side air heat exchanger by switching the refrigerant circulation direction of the air heat source heat pump to the cooling cycle. In the heat source heat pump hot water supply / air conditioner, when defrost conditions for the heat source side air heat exchanger are satisfied, hot water circulated to the refrigerant / water heat exchanger In accordance with the mouth temperature and the outside temperature,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) Stop the compressor once, switch to the cooling cycle after a certain time, restart the compressor and start the defrost operation.
The defrost control part which performs a defrost driving | operation in any of these is provided.

  According to the present invention, when the heat source side air heat exchanger is frosted and the defrost condition is satisfied, according to the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger, (1) The defrosting operation is started by switching the refrigerant circuit to the cooling cycle as it is. (2) Stop the compressor once, switch to the cooling cycle after a certain time, restart the compressor and start the defrost operation. In accordance with the hot water inlet temperature and the outside air temperature, for example, the hot water inlet temperature and the outside air temperature are both higher than the set temperature, for example, A, the hot water inlet By dividing the temperature region in which the temperature and the outside air temperature are equal to or lower than the set temperature into regions such as B, it is possible to perform the defrost operation with the pattern (1) in the A region and the pattern (2) in the B region. Therefore, no matter which pattern is used for defrosting, the refrigerant / water heat exchanger can be prevented from temporarily lowering the low pressure, and the refrigerant / water heat exchanger can be frozen or the low pressure protection function can be activated. It is possible to avoid the defrost operation. In addition, the return time to the heating operation can be shortened and the deterioration of the heating capacity can be minimized as compared with the case where the compressor stop / restart control is uniformly performed during the defrost operation.

  According to the present invention, during the defrost operation, the refrigerant circuit is switched to the cooling cycle as it is depending on the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger, or the defrost operation is started, or the pump down Since the defrost operation is started after the operation and / or the stop / restart control of the compressor are performed, the temporary decrease in the low pressure in the refrigerant / water heat exchanger is prevented. Defrost operation can be performed while avoiding the risk of freezing the water heat exchanger and the low-pressure protection function. In addition, the return time to the heating operation can be shortened and the deterioration of the heating capacity can be minimized as compared with the case where the compressor stop / restart control is uniformly performed during the defrost operation.

1 is a system diagram of an air heat source heat pump hot water supply / air conditioner according to a first embodiment of the present invention. It is a control flow figure at the time of the defrost driving | operation of the air heat source heat pump hot-water supply / air-conditioner shown in FIG. It is the figure which prescribed | regulated the relationship between the external temperature which determines the defrost driving | operation pattern of the air heat source heat pump hot-water supply / air-conditioner shown in FIG. 1, and the hot water inlet temperature of a refrigerant | coolant / water heat exchanger. It is a control flow figure at the time of defrost operation of the air heat source heat pump hot-water supply and air-conditioner concerning a 2nd embodiment of the present invention. It is a control flow figure at the time of defrost operation of an air heat source heat pump hot-water supply / air-conditioner concerning a 3rd embodiment of the present invention.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 shows a system diagram of an air heat source heat pump hot water supply / air conditioner according to the first embodiment of the present invention.
The air heat source heat pump hot water supply / air conditioner 1 is obtained by heating the water with the air heat source heat pump 10 that can select either the cooling cycle or the heating cycle by switching the circulation direction of the refrigerant, and the air heat source heat pump 10. A hot water circulation circuit 20 is provided that can circulate hot water to a load side such as hot water supply or heating.

  In the air heat source heat pump 10, the refrigerant discharged from the compressor 11 circulates through the closed cycle refrigerant circuit 14 including the heat source side air heat exchanger 12 and the refrigerant / water heat exchanger 13 to change the state of the gas and liquid. Repeat. The illustrated refrigerant circuit 14 includes a four-way switching valve 15 on the discharge side of the compressor 11. The refrigerant circulation direction is reversible by operating the four-way switching valve 15, and the refrigerant passes through the heat source side air heat exchanger 12. Either a cooling cycle in which the refrigerant is circulated clockwise to the water / water heat exchanger 13 or a heating cycle in which the refrigerant is circulated counterclockwise to the heat source side air heat exchanger 12 via the refrigerant / water heat exchanger 13 Either one can be selected.

  In addition to the heat source side air heat exchanger 12, the refrigerant / water heat exchanger 13, and the four-way switching valve 15, the refrigerant circuit 14 includes a cooling electronic expansion valve 16, a heating electronic expansion valve 17, and a receiver, as is well known. 18 is provided. The heat source side air heat exchanger 12 is provided with an outside air fan 19 for circulating outside air. The outside air fan 19 is a fan capable of appropriately adjusting the amount of outside air (air flow rate) circulated through the heat source side air heat exchanger 12.

  The hot water circulation circuit 20 is configured such that the water 21 circulated through the pump 21 circulates water and the refrigerant / water heat exchanger 13 provided in the refrigerant circuit 14 exchanges heat with the refrigerant. A load-side device that uses the produced hot water, for example, a heating radiator (use-side heat exchanger) 22 is provided.

  When the heating cycle is selected in the refrigerant circuit 14, the low-temperature and low-pressure gas refrigerant is compressed by the compressor 11 and discharged to the refrigerant circuit 14 as a high-temperature and high-pressure gas refrigerant. This gas refrigerant is guided to the refrigerant / water heat exchanger 13 by the four-way switching valve 15 and circulated counterclockwise, as indicated by solid arrows in FIG. The refrigerant / water heat exchanger 13 in this case is a heat exchanger that exchanges heat between the water in the hot water circulation circuit 20 circulated by the pump 21 and the high-temperature and high-pressure gas refrigerant, and the heat of condensation radiated by condensation of the refrigerant. Functions as a condenser to heat water. As a result, the high-temperature and high-pressure gas refrigerant flowing through the refrigerant circuit 14 is condensed to become a high-pressure liquid refrigerant, and the water flowing through the hot water circulation circuit 20 absorbs heat from the refrigerant and becomes hot water.

  The refrigerant condensed in the refrigerant / water heat exchanger 13 flows into the receiver 18 through the fully opened cooling electronic expansion valve 16. The receiver 18 performs gas-liquid separation of the refrigerant and adjusts the amount of circulating refrigerant. On the downstream side of the receiver 18, a heating electronic expansion valve 17 for reducing the pressure of the high-temperature and high-pressure liquid refrigerant is disposed. When the refrigerant passes through the heating electronic expansion valve 17, the high-pressure liquid refrigerant is depressurized to become a low-temperature low-pressure gas-liquid two-phase refrigerant, which is led to the heat source side air heat exchanger 12. The gas-liquid two-phase refrigerant introduced into the heat source side air heat exchanger 12 functioning as an evaporator absorbs heat from the outside air by evaporating and gasifying it by exchanging heat with the outside air.

  By passing through the heat source side air heat exchanger 12, the low-temperature and low-pressure gas refrigerant absorbed and gasified from the outside air is again sucked into the compressor 11 through the four-way switching valve 15. The low-temperature and low-pressure gas refrigerant sucked into the compressor 11 in this way is compressed again by the compressor 11 to become a high-temperature and high-pressure gas refrigerant, and thereafter the same cycle is repeated to repeatedly change the state of the gas and liquid. It is known that during the heating cycle, especially when the outside air temperature is low, moisture in the air freezes on the outer peripheral surface of the heat source side air heat exchanger 12 to cause a frosting phenomenon.

  This frost hinders heat exchange between the refrigerant and the outside air in the heat source side air heat exchanger 12 and lowers the heat exchange efficiency. Therefore, the frost is formed by an appropriate method, for example, the temperature of the heat source side air heat exchanger 12. By detecting using the outside air temperature, it is necessary to perform defrost operation to remove frost. In the present embodiment, the defrosting operation is performed by operating the four-way switching valve 15 in the refrigerant circuit 14 described above to reverse the refrigerant circulation direction and switching to a cooling cycle in which the refrigerant is circulated in the direction of the broken arrow in the figure. Is called.

  During the defrost operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 is guided to the heat source side air heat exchanger 12 via the four-way switching valve 15 as indicated by a broken line arrow in FIG. Circulated in the direction of rotation. In this case, the heat source side air heat exchanger 12 functions as a condenser in which heat is exchanged between the outside air and the high-temperature and high-pressure gas refrigerant, and the refrigerant condenses to release heat of condensation. As a result, the high-temperature and high-pressure gas refrigerant is condensed to become a high-pressure liquid refrigerant, and the frost adhering to the heat source side air heat exchanger 12 is melted by heat radiation (condensation heat). The refrigerant condensed in the heat source side air heat exchanger 12 flows into the receiver 18 through the fully-open heating electronic expansion valve 17. The receiver 18 performs gas-liquid separation of the refrigerant and adjusts the amount of circulating refrigerant.

  A cooling electronic expansion valve 16 that depressurizes the high-temperature and high-pressure liquid refrigerant is disposed downstream of the receiver 18. When the refrigerant passes through the cooling electronic expansion valve 16, the high-pressure liquid refrigerant is depressurized to be a low-temperature low-pressure gas-liquid two-phase refrigerant. This refrigerant is guided to the refrigerant / water heat exchanger 13 functioning as an evaporator, and is heat-exchanged with the hot water supplied from the hot water circulation circuit 20 to be vaporized. As a result, the gas-liquid two-phase refrigerant becomes a low-temperature and low-pressure gas refrigerant and is again sucked into the compressor 11 via the four-way switching valve 15. The low-temperature and low-pressure gas refrigerant sucked into the compressor 11 is recompressed by the compressor 11 to become a high-temperature and high-pressure gas refrigerant, and thereafter the same cycle is repeated to repeatedly change the state of gas and liquid.

  On the other hand, in the refrigerant / water heat exchanger 13 functioning as an evaporator during defrost operation, hot water on the hot water circulation circuit 20 side is used as a heat source for vaporizing the gas-liquid two-phase refrigerant. In this case, in the case where both the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger 13 are low, when the defrost operation is started by switching from the heating cycle to the cooling cycle, a temporary low pressure abnormality is caused. There is a risk that the low-pressure protection function is activated and the operation is stopped, or the refrigerant / water heat exchanger 13 is frozen.

Therefore, based on the detected values of the water temperature sensor 31 for detecting the temperature of the hot water circulated to the refrigerant / water heat exchanger 13 through the hot water circulation circuit 20 and the outside air temperature sensor 32, the defrost operation is performed as follows. A defrost control unit 30 is provided. FIG. 2 shows a control flow chart of this defrost operation.
As shown in FIG. 2, during the heating operation, the defrost control unit 30 performs the heat source side based on the temperature information from the outside air temperature sensor 32 and the heat exchange temperature sensor 33 provided in the heat source side air heat exchanger 12. It is monitored whether or not the defrost condition for the air heat exchanger 12 is satisfied (step S1).

  When it is detected that the defrost condition is satisfied, the process proceeds to step S2, where it is determined whether or not the condition continues for a predetermined time (for example, 40 seconds). If NO, the process returns to step S1. If YES, the process proceeds to step S3, the defrost start flag is established, and the process proceeds to step S4. In step S4, the hot water inlet temperature and the outdoor air temperature detected by the water temperature sensor 31 and the outside air temperature sensor 32 are temperature regions A and B defined from the relationship between the outside air temperature and the hot water inlet temperature, as shown in FIG. , C, and D, it is determined in any of the following patterns (1) to (3) whether the defrost operation is started.

(1) The refrigerant circuit 14 is switched as it is from the heating cycle to the cooling cycle by the four-way switching valve 15 and the defrosting operation is started.
(2) The cooling electronic expansion valve 16 is fully opened, the heating electronic expansion valve 17 is fully closed, and after performing a pump-down operation for collecting the refrigerant in the receiver 18 in the refrigerant circuit 14, the refrigerant circuit 14 is switched to the four-way switching valve. 15, the heating cycle is switched to the cooling cycle, and the defrosting operation is started.
(3) After the pump-down operation of (2) above, the operation of the compressor 11 is once stopped, and after a predetermined time, the refrigerant circuit 14 is switched from the heating cycle to the cooling cycle by the four-way switching valve 15, and the compressor 11 is restarted. Start defrosting.

  That is, when the hot water inlet temperature and the outside air temperature are in the temperature region A where the hot water inlet temperature is 30 ° C. or higher and the outside air temperature is 0 ° C. or higher, for example, the operation pattern of (1) is used and step S8 is performed. Then, the defrost operation is started. Further, when the hot water inlet temperature is less than 30 ° C., 25 ° C. or more, and the outside air temperature is in the temperature region B of less than 0 ° C. or −15 ° C. or more, the operation pattern of (2) is set, and in step S5 After the pump down operation, the process proceeds to step S8, and the defrost operation is started.

Furthermore, when the temperature of the hot water inlet is less than 25 ° C., 20 ° C. or more, and the outside air temperature is in the temperature region C less than −15 ° C., the operation pattern of (3) is set, and the pump down operation is performed in step S6. Then, the process proceeds to step S7, and further, stop / restart control of the compressor 11 is performed. Then, the process proceeds to step S8, and the defrost operation is started.
In addition, when the temperature of the hot water inlet is less than 20 ° C., it is a region D where the defrost operation is prohibited regardless of the outside air temperature, and when entering the temperature region D, for example, on the load side The defrosting operation is performed after the warm water temperature is recovered to 20 ° C. or more by stopping the use of the warm water or heating the warm water with an electric heater.

  In this way, when the defrost operation is performed and the frost of the heat source side air heat exchanger 12 is melted, the temperature of the heat source side air heat exchanger 12 rises. When this temperature increase is detected by the heat exchanger temperature sensor 33, the process proceeds to step S9, the defrost operation is terminated, and the heating operation is restarted. The defrost operation is performed by switching the heating cycle to the cooling cycle by the four-way switching valve 15, but it is desirable to reduce the rotation speed of the compressor 11 to the minimum rotation speed when the four-way switching valve 15 is switched. This is because a rapid decrease in low pressure is prevented in the defrosting operation after switching the four-way switching valve 15 by reducing the rotational speed of the compressor 11 before switching the four-way switching valve 15.

  As described above, according to the present embodiment, the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger 13 are detected, and the operation pattern at the start of the defrost operation is changed according to the temperatures. I am doing so. In the case of the temperature region A in which the hot water inlet temperature and the outside air temperature are both higher than the set temperature, a situation in which the low pressure temporarily decreases abnormally does not occur when switching to the defrost operation, so the defrost condition is satisfied. Then, even if the defrost operation is started as it is with the above pattern (1), there is no risk that the low-pressure protection function is activated due to abnormally low pressure or the refrigerant / water heat exchanger 13 is frozen. Defrost operation can be carried out quickly.

  In the case of the temperature region B where the hot water inlet temperature and the outside air temperature are both lower than the set temperature, after performing the pump down operation for collecting the refrigerant in the receiver in the pattern (2), switch to the cooling cycle and perform the defrost operation. I'm trying to get started. For this reason, at the time of switching to the defrost operation, the defrost operation can be started while the high pressure liquid refrigerant is gradually supplied from the receiver to the refrigerant / water heat exchanger 13, and the low pressure protection function due to the abnormal decrease in the low pressure can be started. The risk of operation and freezing in the refrigerant / water heat exchanger 13 can be avoided.

  Further, in the case of the temperature region C where the hot water inlet temperature and the outside air temperature are lower than the temperature region B, the pump down operation is performed in the pattern (3), and then the stop / restart control of the compressor 11 is performed to perform the defrost operation. Like to start. For this reason, even when the defrosting is performed from the state where the opening degree of the electronic expansion valve 17 for heating is considerably reduced in the heating operation under a low outside temperature and the evaporation pressure is very low, the pump down operation is performed. After that, the compressor 11 is once stopped, the pressure is balanced, and then restarted to start the defrost operation, thereby reliably preventing a situation in which the low pressure is temporarily lowered abnormally in the refrigerant / water heat exchanger 13. Therefore, the operation of the low-pressure protection function and the risk of freezing in the refrigerant / water heat exchanger 13 can be avoided.

  Therefore, even if the defrost operation is performed in any one of the patterns (1), (2), and (3), the refrigerant / water heat exchanger 13 is prevented from temporarily lowering the low pressure abnormally, and the refrigerant / The defrosting operation can be performed smoothly and quickly by avoiding the freezing risk of the water heat exchanger 13 and the operation of the low-pressure protection function. In addition, during defrost operation, the time to return to heating operation is shortened as much as possible, and the decline in heating capacity is kept to a minimum, compared with the case where pump down operation and compressor 11 stop / restart control are performed uniformly. be able to.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
This embodiment differs from the first embodiment described above in the manner of dividing the temperature region based on the hot water inlet temperature and the outside air temperature and the corresponding defrost operation start pattern. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, the hot water inlet temperature and the outside air temperature detected by the water temperature sensor 31 and the outside air temperature sensor 32 are the right region (this region is referred to as temperature region A1) and the left region (shown as temperature region A1) shown in FIG. This is referred to as temperature region B1), and the defrosting operation is started in either of the following patterns (1) or (2) depending on which region of the defrosting prohibition region D the hot water inlet temperature is less than 20 ° C. I am trying to decide.

(1) The refrigerant circuit 14 is switched as it is from the heating cycle to the cooling cycle by the four-way switching valve 15 and the defrosting operation is started.
(2) The cooling electronic expansion valve 16 is fully opened, the heating electronic expansion valve 17 is fully closed, and after performing a pump-down operation for collecting the refrigerant in the receiver 18 in the refrigerant circuit 14, the refrigerant circuit 14 is switched to the four-way switching valve. 15, the heating cycle is switched to the cooling cycle, and the defrosting operation is started.

  As described above, the temperature region is a region where the hot water inlet temperature is 30 ° C. or higher and the outside air temperature is −15 ° C. or higher, and the temperature region is a region where the hot water inlet temperature is less than 30 ° C. and the outside air temperature is less than −15 ° C. When the hot water inlet temperature and the outside air temperature are in the temperature region A1, the defrost operation is performed with the operation pattern of (1) above. When the temperature is in the temperature region B1, the above (2) The defrost operation is performed with the operation pattern. That is, when the hot water inlet temperature and the outside air temperature are in the temperature region A1, as shown in FIG. 4, in step S4A, the operation pattern of (1) is set, and the process proceeds to step S8 as it is, and the defrost operation is performed. Will be started. Further, when the temperature range is set to B1, the operation pattern of (2) is set, and after the pump-down operation is performed in step S5, the process proceeds to step S8 and the defrost operation is started.

  Therefore, according to the present embodiment, even if the defrost operation is performed in any of the patterns (1) and (2), a temporary low-pressure abnormal drop of the refrigerant in the refrigerant / water heat exchanger 13 is prevented. The defrosting operation can be performed smoothly and quickly while avoiding the freezing risk of the refrigerant / water heat exchanger 13 and the operation of the low-pressure protection function. Moreover, compared with what performs pump down operation uniformly at the time of a defrost operation, the return time to heating operation can be shortened as much as possible, and the fall of heating capability can be suppressed to the minimum.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS.
This embodiment differs from the first embodiment described above in the manner of dividing the temperature region based on the hot water inlet temperature and the outside air temperature and the corresponding defrost operation start pattern. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, as in the second embodiment, the hot water inlet temperature and the outside air temperature detected by the water temperature sensor 31 and the outside air temperature sensor 32 are displayed on the right side area of the two-dot chain line shown in FIG. ), The left region (this is referred to as temperature region B1), and the defrosting prohibition region D where the hot water inlet temperature is less than 20 ° C., which of the following (1) or (2) The pattern determines whether to start defrost operation.

(1) The refrigerant circuit 14 is switched as it is from the heating cycle to the cooling cycle by the four-way switching valve 15 and the defrosting operation is started.
(2) The operation of the compressor 11 is once stopped, and after a predetermined time, the refrigerant circuit 14 is switched from the heating cycle to the cooling cycle by the four-way switching valve 15, and the compressor 11 is restarted to start the defrost operation.

  As described above, the temperature region is a region where the hot water inlet temperature is 30 ° C. or higher and the outside air temperature is −15 ° C. or higher, and the temperature region is a region where the hot water inlet temperature is less than 30 ° C. and the outside air temperature is less than −15 ° C. When the hot water inlet temperature and the outside air temperature are in the temperature region A1, the defrost operation is performed with the operation pattern of (1) above. When the temperature is in the temperature region B1, the above (2) The defrost operation is performed with the operation pattern. That is, when the hot water inlet temperature and the outside air temperature are in the temperature region A1, as shown in FIG. 5, the operation pattern of (1) is set in step S4B, and the process proceeds to step S8 as it is, and the defrost operation is performed. Will be started. Further, when the temperature range is set to B1, the operation pattern of (2) is set, and after stopping / restarting control of the compressor 11 is performed in step S7, the process proceeds to step S8 and the defrost operation is started. It will be.

  Therefore, according to the present embodiment, even if the defrost operation is performed in any of the patterns (1) and (2), a temporary low-pressure abnormal drop of the refrigerant in the refrigerant / water heat exchanger 13 is prevented. The defrosting operation can be performed smoothly and quickly while avoiding the freezing risk of the refrigerant / water heat exchanger 13 and the operation of the low-pressure protection function. Moreover, compared with what performs stop / restart control of the compressor 11 uniformly at the time of a defrost operation, the return time to heating operation can be shortened as much as possible, and the fall of heating capability can be suppressed to the minimum.

  In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary, it can change suitably. For example, the example of the temperature region of the water inlet temperature and the outside air temperature shown in FIG. 3 is merely an example, and naturally differs depending on the specifications of the air heat source heat pump hot water supply / air conditioner. Good.

DESCRIPTION OF SYMBOLS 1 Air heat source heat pump hot-water supply and air conditioner 10 Air heat source heat pump 11 Compressor 12 Heat source side air heat exchanger 13 Refrigerant / water heat exchanger 14 Refrigerant circuit 15 Four-way switching valve 16 Cooling electronic expansion valve 17 Heating electronic expansion valve 18 Receiver 20 Hot water circulation circuit 21 Pump 22 Radiator (use side heat exchanger)
30 Defrost control unit 31 Water temperature sensor 32 Outside air temperature sensor 33 Heat exchange temperature sensor

Claims (3)

The refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including a heat source side air heat exchanger and a refrigerant / water heat exchanger, and the circulation direction of the refrigerant is reversible, so that the cooling cycle and the heating cycle are recirculated. One of the air heat source heat pumps that can be selected, and hot water circulation in which water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger to become hot water and circulates the hot water to the load side An air heat source heat pump hot water supply / air conditioning apparatus that performs a defrost operation of the heat source side air heat exchanger by switching a refrigerant circulation direction of the air heat source heat pump to the cooling cycle.
When the defrost condition for the heat source side air heat exchanger is satisfied, depending on the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation.
(3) After the pump-down operation of (2) above, the compressor is once stopped, switched to the cooling cycle after a certain time, the compressor is restarted, and the defrost operation is started.
An air heat source heat pump hot water supply / air conditioner comprising a defrost control unit for performing defrost operation in any of the above. The refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including a heat source side air heat exchanger and a refrigerant / water heat exchanger, and the circulation direction of the refrigerant is reversible, so that the cooling cycle and the heating cycle are recirculated. One of the air heat source heat pumps that can be selected, and hot water circulation in which water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger to become hot water and circulates the hot water to the load side An air heat source heat pump hot water supply / air conditioning apparatus that performs a defrost operation of the heat source side air heat exchanger by switching a refrigerant circulation direction of the air heat source heat pump to the cooling cycle.
When the defrost condition for the heat source side air heat exchanger is satisfied, depending on the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) After performing a pump-down operation in which the refrigerant is collected in the receiver in the refrigerant circuit, the cooling cycle is switched to start the defrost operation.
An air heat source heat pump hot water supply / air conditioner comprising a defrost control unit for performing defrost operation in any of the above. The refrigerant discharged from the compressor is circulated through a closed cycle refrigerant circuit including a heat source side air heat exchanger and a refrigerant / water heat exchanger, and the circulation direction of the refrigerant is reversible, so that the cooling cycle and the heating cycle are recirculated. One of the air heat source heat pumps that can be selected, and hot water circulation in which water circulated through the pump is heat-exchanged with the refrigerant in the refrigerant / water heat exchanger to become hot water and circulates the hot water to the load side An air heat source heat pump hot water supply / air conditioning apparatus that performs a defrost operation of the heat source side air heat exchanger by switching a refrigerant circulation direction of the air heat source heat pump to the cooling cycle.
When the defrost condition for the heat source side air heat exchanger is satisfied, depending on the inlet temperature and the outside air temperature of the hot water circulated to the refrigerant / water heat exchanger,
(1) The refrigerant circuit is switched to the cooling cycle as it is and the defrost operation is started.
(2) Stop the compressor once, switch to the cooling cycle after a certain time, restart the compressor and start the defrost operation.
An air heat source heat pump hot water supply / air conditioner comprising a defrost control unit for performing defrost operation in any of the above.

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