JP2017026159A - Heat pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump device by which a small size, an inexpensive price and high reliability are obtained and which suppresses refrigerant stagnation and maintains comfortability during defrosting while having high energy saving characteristics.SOLUTION: A heat pump device 1 has a refrigerant circuit 8 in which a compressor 2, a first heat exchange unit 4, an expansion device 6 and a second heat exchanger 7 are connected through piping and a refrigerant flows, and a control part 21 controlling operation of the refrigerant circuit 8. The first heat exchange unit 4 has plural auxiliary heat exchange parts connected in series, and an auxiliary expansion device 43 provided between the plural auxiliary heat exchange parts. The control part 21 has a defrosting time control means 22 which increases a pressure difference between the refrigerant flowing in the upstream side of the auxiliary expansion device 43 when defrosting the auxiliary heat exchange parts and the refrigerant flowing in the downstream side of the auxiliary expansion device 43 by the auxiliary expansion device 43.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a heat pump device including a refrigerant circuit.

  2. Description of the Related Art Conventionally, there is a heat pump device that conveys heat to a heat demand section by a refrigeration cycle using outdoor air as a heat source, for example. In this heat pump device, means for removing frost generated in a heat exchanger installed outdoors when carrying warm heat to a heat demanding unit has been proposed.

  In Patent Document 1, a plurality of first switching valves 25 provided between an outlet side of the outdoor heat exchangers 22 installed in parallel and a suction side of the compressor 21, and the outdoor heat exchangers 22 are arranged. An air conditioner including a second switching valve 26 provided between the outlet side and the discharge side of the compressor 21 is disclosed. This patent document 1 discloses that in the outdoor heat exchanger 22 where defrosting is required, by opening the first switching valve 25 and closing the second switching valve 26, only the outdoor heat exchanger 22 is supplied from the compressor 21. The discharged hot gas refrigerant flows and defrosts. At that time, after being discharged from the compressor 21, it flows in the reverse direction from the outlet side of the outdoor heat exchanger 22 having the defrosting request toward the inlet side, and the refrigerant used for the defrosting and the compressor 21 After being discharged, the refrigerant used for heating through the indoor heat exchanger 41 joins. Then, the merged refrigerant flows through the outdoor heat exchanger 22 where there is no defrost request and absorbs heat. Thereby, this conventional technology tries to defrost the outdoor heat exchanger 22 having a defrosting request while continuing heating in the indoor heat exchanger 41.

  Patent Document 2 discloses a showcase in which a cooling operation is performed by the first evaporator 15c and the second evaporator 16c. In this prior art, by switching a plurality of valves provided in the refrigerant circuit, the high-temperature refrigerant discharged from the compressor 14a circulates in the condenser 14b and dissipates heat, and then does not pass through the expansion valve 23. It distribute | circulates to the 1st evaporator 15c and defrosts the 1st evaporator 15c. And the refrigerant | coolant which flowed out from the 1st evaporator 15c distribute | circulates to the expansion valve 23, absorbs heat with the 2nd evaporator 16c, and cools the inside of a showcase. As described above, Patent Document 2 intends to perform a defrost cooling operation in which the first evaporator 15c is defrosted while the inside of the showcase is cooled by the second evaporator 16c.

JP 2008-157558 A (FIG. 4, pages 7 to 8) JP 2008-133998 A (FIG. 6, page 5)

  However, the air conditioner disclosed in Patent Document 1 causes the refrigerant to flow in parallel to the plurality of outdoor heat exchangers 22 in a normal heating operation without defrosting, but in the heating operation with defrosting, the defrosting is performed. The refrigerant flowing through the outdoor heat exchanger 22 having the request is circulated in series to the outdoor heat exchanger 22 having no defrosting request. For this reason, in Patent Document 1, the distribution route of the refrigerant is complicated, and a large number of switching valves are required for switching the complicated distribution route. Therefore, there are problems that it is difficult to reduce the size of the apparatus, the cost is high, and the failure rate is high and the reliability is low. Moreover, when there are many switching valves, the place where a refrigerant | coolant pool generate | occur | produces increases and there also exists a problem which requires a lot of refrigerant | coolants. Further, in Patent Document 1, since defrosting is performed with a high-temperature refrigerant discharged from the compressor 21, the defrosting itself is processed at an early stage, but energy consumption is intense. Also, Patent Document 2 has the same problem as Patent Document 1.

  The present invention was made against the background of the above problems, and is a heat pump device that is small, inexpensive, highly reliable, suppresses refrigerant accumulation, has high energy savings, and maintains comfort during defrosting. Is to provide.

  The heat pump device according to the present invention includes a refrigerant circuit in which a compressor, a first heat exchange unit, an expansion device, and a second heat exchanger are connected by a pipe and through which refrigerant flows, and a control unit that controls the operation of the refrigerant circuit. And the first heat exchange unit has a plurality of sub heat exchange units connected in series and a sub expansion device provided between the plurality of sub heat exchange units, and a control unit The defrosting control means for increasing the pressure difference between the refrigerant flowing upstream of the sub-expansion device and the refrigerant flowing downstream of the sub-expansion device by the sub-expansion device when defrosting the auxiliary heat exchange unit. It is characterized by having.

  According to the present invention, when the defrosting control means defrosts the auxiliary heat exchange unit, the pressure difference between the refrigerant flowing upstream of the auxiliary expansion device and the refrigerant flowing downstream of the auxiliary expansion device is calculated. In order to raise with a subexpansion apparatus, heating or cooling is continued by the other sub heat exchange part, defrosting at least one sub heat exchange part. For this reason, the user of a heat pump apparatus does not impair comfort at the time of defrosting.

1 is a schematic diagram showing a heat pump device 1 according to Embodiment 1. FIG. 4 is a schematic diagram showing a heat pump device 1 according to Embodiment 2. FIG.

  Hereinafter, embodiments of a heat pump device according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below. Moreover, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing a heat pump device 1 according to the first embodiment. The heat pump device 1 will be described with reference to FIG. As shown in FIG. 1, the heat pump device 1 constituting an air conditioner or the like includes a refrigerant circuit 8 and a control unit 21. Among these, the refrigerant circuit 8 is a circuit in which the compressor 2, the first heat exchange unit 4, the expansion device 6, and the second heat exchanger 7 are connected by piping, and the refrigerant circulates. In addition, the refrigerant | coolant used is a refrigerant | coolant which carries out a gas-liquid two-phase within the range of the temperature and pressure to be used like a fluorocarbon type | system | group, a hydrocarbon type | system | group, a carbon dioxide, etc.

  The refrigerant circuit 8 absorbs heat from one of the outdoor air 11 and the indoor air 12, for example, and dissipates heat to the other using the condensation and vaporization of the circulating refrigerant. In the refrigerant circuit 8, heat is efficiently transferred between the outdoor air 11 and the indoor air 12 via the refrigerant with respect to the power required for the compression of the compressor 2. When the indoor air 12 is cooled, the refrigerant that has been reduced in temperature and pressure by the expansion device 6 to be in a gas-liquid two-phase state flows to the second heat exchanger 7 installed in the room. On the other hand, when the indoor air 12 is heated, the refrigerant that has become a high-temperature and high-pressure state in the compressor 2 and is in a gas phase flows through the second heat exchanger 7. As described above, the refrigerant flow direction in the refrigerant circuit 8 is reversed when the indoor air 12 is cooled or heated.

(Compressor 2, pumping switching unit 3)
The compressor 2 pumps the refrigerant in a gas phase to increase the temperature and pressure. On the discharge side of the compressor 2, a pressure feed switching unit 3 is provided. The pressure feed switching unit 3 switches the refrigerant flow direction in the refrigerant circuit 8. This pressure feed switching unit 3 is, for example, a four-way valve, and four connection paths A, B, C, and D are connected to the four-way valve. Among these, the pumping switching unit 3 is connected in the first state in which the connection path A and the connection path B, the connection path C and the connection path D are connected, the connection path A and the connection path C, and the connection path B and the connection path D are connected. The second state can be changed to the second state. For example, the connection path A is connected to the discharge side of the compressor 2, the connection path B is connected to the second heat exchanger 7, the connection path C is connected to the first heat exchange unit 4, and the connection path D is It is connected to the suction side of the compressor 2. By switching the pressure feed switching unit 3, it is changed whether the refrigerant discharged from the compressor 2 flows into the first heat exchange unit 4 or the second heat exchanger 7.

(First heat exchange unit 4)
The first heat exchange unit 4 is used outdoors. For example, the outdoor air 11 blown by a fan (not shown) is used as a heat source to exchange heat between the outdoor air 11 and the refrigerant. . The 1st heat exchange unit 4 is provided with the 1st sub heat exchange part 41 and the 2nd sub heat exchange part 42, and these 1st sub heat exchange parts 41 and the 2nd sub heat exchange part 42 is connected in series. Thereby, the refrigerant does not flow in the parallel direction but always flows in the series direction in the first sub heat exchange unit 41 and the second sub heat exchange unit 42. Note that the number of sub heat exchange units is not limited to two, and a plurality of sub heat exchange units may be installed.

(Sub-expansion device 43)
A sub-expansion device 43 is provided between the first sub-heat exchange unit 41 and the second sub-heat exchange unit 42. The sub-expansion device 43 is a high-pressure liquid-phase refrigerant. Is expanded to lower the temperature and pressure to make a gas-liquid two-phase refrigerant. The sub-expansion device 43 is, for example, an expansion valve that changes the amount of refrigerant flow and the pressure of the refrigerant according to the degree of opening. Since the sub-expansion device 43 is provided between the first sub-heat exchange unit 41 and the second sub-heat exchange unit 42, the refrigerant flowing through the first heat exchange unit 4 is always sub-expansion. Flows into the device 43.

(Sub bypass valve 45)
Further, the refrigerant circuit 8 is provided with a sub-bypass circuit 44 that bypasses the sub-expansion device 43, and the sub-bypass circuit 44 is provided with a sub-bypass valve 45 that adjusts the amount of refrigerant flowing in the sub-bypass circuit 44. It has been. When the sub bypass valve 45 is closed, all the refrigerant flowing through the first heat exchange unit 4 does not flow into the sub bypass circuit 44 but flows into the sub expansion device 43. On the other hand, when the sub bypass valve 45 is opened, the refrigerant flowing through the first heat exchange unit 4 flows into the sub bypass circuit 44 and the sub expansion device 43 separately. At this time, if the sub-expansion device 43 is throttled, the refrigerant flowing into the sub-expansion device 43 decreases, and a large amount of the remaining refrigerant flows into the sub-bypass circuit 44.

(Inflow switching part 5)
In the first heat exchange unit 4, an inflow switching unit 5 is provided on one end side of the first sub heat exchange unit 41, and the inflow switching unit 5 is used for the refrigerant in the first heat exchange unit 4. The distribution direction is switched. The inflow switching unit 5 is a four-way valve, for example, similarly to the pressure-feeding switching unit 3, and the four connection paths A, B, C, and D are connected to the four-way valve. Of these, the inflow switching unit 5 includes the first state in which the connection path A and the connection path B, the connection path C and the connection path D are connected, the connection path A and the connection path C, and the connection path B and the connection path D are connected. The second state can be changed to the second state. For example, the connection path A is connected to the expansion device 6, the connection path B is connected to the first auxiliary heat exchange unit 41, the connection path C is connected to the second auxiliary heat exchange unit 42, and the connection path D is pumped. It is connected to the switching unit 3.

  By switching the inflow switching unit 5, when the refrigerant flows into the first heat exchange unit 4, the refrigerant first flows into the first sub heat exchange unit 41 and then flows into the second sub heat exchange unit 42. Or, first, it is changed whether it flows into the 2nd sub heat exchange part 42, and flows into the 1st sub heat exchange part 41 after that. Further, by switching the inflow switching unit 5, the refrigerant flowing out from the first heat exchange unit 4 to the side opposite to the inflow source flows into the suction side of the compressor 2 or flows into the expansion device 6. Is changed.

(First temperature detector 41a and second temperature detector 42a)
The refrigerant circuit 8 includes two first temperature detection units 41a and a second temperature detection unit 42a that detect the temperature of the refrigerant. For example, the first sub heat exchange unit 41 and the sub expansion device 43 are provided. And between the second auxiliary heat exchanging unit 42 and the auxiliary expansion device 43. The first temperature detector 41a and the second temperature detector 42a indirectly detect the temperature of the refrigerant by measuring the temperature of the pipe.

(Expansion device 6)
The expansion device 6 expands a high-pressure liquid-phase refrigerant to lower the temperature and the pressure to obtain a gas-liquid two-phase refrigerant. The expansion device 6 is, for example, an expansion valve that changes the flow rate of the refrigerant and the pressure of the refrigerant at the opening degree.

(Bypass valve 62)
The refrigerant circuit 8 is provided with a bypass circuit 61 that bypasses the expansion device 6, and the bypass circuit 61 is provided with a bypass valve 62 that adjusts the amount of refrigerant flowing in the bypass circuit 61. When the bypass valve 62 is closed, all the refrigerant flowing through the refrigerant circuit 8 does not flow into the bypass circuit 61 but flows into the expansion device 6. On the other hand, when the bypass valve 62 is opened, the refrigerant flowing through the refrigerant circuit 8 flows into the bypass circuit 61 and the expansion device 6 separately. At this time, if the expansion device 6 is throttled, the refrigerant flowing into the expansion device 6 decreases, and the remaining large amount of refrigerant flows into the bypass circuit 61.

(Second heat exchanger 7)
The second heat exchanger 7 is used indoors. For example, the indoor heat 12 blown by a fan (not shown) is used as a heat source, and load heat exchange is performed to exchange heat between the indoor air 12 and the refrigerant. It is a vessel.

(Control unit 21)
The controller 21 controls the operation of the refrigerant circuit 8. The control unit 21 includes a defrosting control unit 22, a threshold determination unit 23, and an end determination unit 24.

(Defrosting control means 22)
When the defrosting control means 22 defrosts the first sub heat exchange unit 41 or the second sub heat exchange unit 42, the refrigerant flowing upstream of the sub expansion device 43 and the downstream of the sub expansion device 43. The sub-expansion device 43 increases the pressure difference with the refrigerant flowing to the side. The defrosting control means 22 can also be configured to open the bypass valve 62 when defrosting the first sub heat exchange unit 41 or the second sub heat exchange unit 42. Further, the defrosting control means 22 may be configured to close the sub bypass valve 45 when the first sub heat exchange unit 41 or the second sub heat exchange unit 42 is defrosted. In addition, the defrosting control means 22 can also control the operation of the expansion device 6.

(Threshold determination means 23, end determination means 24)
The threshold value determination unit 23 determines whether or not the temperature of the refrigerant detected by the first temperature detection unit 41a or the second temperature detection unit 42a is equal to or higher than a predetermined threshold value. This threshold can be set to 0 ° C., for example, but can be changed as appropriate. Then, the end determination unit 24 determines that the temperature of the refrigerant is equal to or higher than the threshold value while the first sub heat exchange unit 41 or the second sub heat exchange unit 42 is defrosted. In this case, it is determined that the defrosting of the first sub heat exchange unit 41 or the second sub heat exchange unit 42 has been completed.

  Next, operation | movement of the heat pump apparatus 1 which concerns on this Embodiment 1 is demonstrated.

(Normal heating operation)
First, the normal heating operation, that is, the operation of absorbing heat by the first heat exchange unit 4 and radiating heat by the second heat exchanger 7 will be described. At this time, the refrigerant is the compressor 2, the pressure switching unit 3, the second heat exchanger 7, the expansion device 6, the inflow switching unit 5, the first heat exchange unit 4, the inflow switching unit 5, the pressure feeding switching unit 3, It distributes in order of the compressor 2. In the first heat exchange unit 4, both the first sub heat exchange unit 41 and the second sub heat exchange unit 42 only absorb heat from the outdoor air 11. The refrigerant may flow into the auxiliary heat exchange unit 41 first, or the refrigerant may flow into the second auxiliary heat exchange unit 42 first. Further, the bypass valve 62 is closed to sufficiently expand the refrigerant by the expansion device 6. Note that the pressure loss in the first heat exchange unit 4 is reduced as much as possible by fully opening the sub expansion device 43 and opening the sub bypass valve 45, or both of them.

  As described above, the high-temperature refrigerant discharged from the compressor 2 is radiated by exchanging heat with the indoor air 12 in the second heat exchanger 7 to heat the room. At that time, the refrigerant liquefied at a low temperature is expanded by the expansion device 6 to be low-pressure to be gas-liquid two-phase. Then, the refrigerant absorbs heat from the outdoor air 11 in the first heat exchange unit 4 and is vaporized, and is sucked into the compressor 2 to be increased in temperature and pressure again. Thereby, the heat pump device 1 can continuously heat the room.

(Normal cooling operation)
Next, a normal cooling operation, that is, an operation in which heat is radiated by the first heat exchange unit 4 and heat is absorbed by the second heat exchanger 7 will be described. At this time, the refrigerant is the compressor 2, the pressure switching unit 3, the inflow switching unit 5, the first heat exchange unit 4, the inflow switching unit 5, the expansion device 6, the second heat exchanger 7, the pressure feeding switching unit 3, It distributes in order of the compressor 2. Even in this normal cooling operation, in the first heat exchange unit 4, both the first sub heat exchange unit 41 and the second sub heat exchange unit 42 only radiate heat to the outdoor air 11. As in the case of the heating operation, the refrigerant may flow into the first auxiliary heat exchange unit 41 from the inflow switching unit 5 or the refrigerant flows into the second auxiliary heat exchange unit 42 first. Also good. Further, the bypass valve 62 is closed to sufficiently expand the refrigerant by the expansion device 6. Note that the pressure loss in the first heat exchange unit 4 is reduced as much as possible by fully opening the sub expansion device 43 and opening the sub bypass valve 45, or both of them.

  As described above, the high-temperature refrigerant discharged from the compressor 2 is radiated by exchanging heat with the outdoor air 11 in the first heat exchange unit 4. At that time, the refrigerant liquefied at a low temperature is expanded by the expansion device 6 to be low-pressure to be gas-liquid two-phase. The refrigerant absorbs heat from the indoor air 12 in the second heat exchanger 7 to cool the room. Thereafter, the refrigerant that has absorbed heat and is vaporized is sucked into the compressor 2 and is again heated to high temperature and pressure. Thereby, the heat pump device 1 can continuously cool the room.

(Defrosting operation)
As described above, in the heat pump device 1 such as an air conditioner, the normal heating operation and the normal cooling operation are mainly performed. However, if the normal heating operation is continued, in the first heat exchange, the heat contained in the outdoor air 11 is exchanged between the low-temperature refrigerant and the outdoor air 11, so that the moisture contained in the outdoor air 11 is changed to the outer surface of the first heat exchange unit 4. It adheres to and becomes frost. As a result, the heat resistance increases, and the heat exchange efficiency of the first heat exchange unit 4 decreases. In this case, a defrosting operation is required.

(High temperature defrosting operation)
As the defrosting operation, the high temperature defrosting operation will be described. In this high-temperature defrosting operation, the refrigerant flow direction is the same as in the normal cooling operation. That is, the high-temperature refrigerant discharged from the compressor 2 flows into the first heat exchange unit 4. Thereby, the frost adhering to the 1st heat exchange unit 4 is melted by the high temperature refrigerant | coolant, and is defrosted. At that time, in the fan provided in the vicinity of the first heat exchange unit 4, heat used for defrosting at the time of the high temperature defrosting operation escapes to the outdoor air 11 having a low temperature at the time of the normal heating operation. Is stopped to suppress

  However, in this high-temperature defrosting operation, low-temperature refrigerant flows through the second heat exchanger 7, and even if the fan provided in the vicinity of the second heat exchanger 7 is stopped, the removal is performed. Part of the heat source for frosting is covered with indoor air 12. For this reason, defrosting is required during normal heating operation, and when high-temperature defrosting operation is performed, the temperature of the indoor air 12 is lowered and it is difficult to maintain comfort in the room. Therefore, the heat pump device 1 according to the first embodiment ensures comfort by enabling execution of the defrost heating operation and the semi-high temperature defrost operation in addition to the high temperature defrost operation.

(Defrost heating operation)
First, defrosting heating operation, that is, while defrosting one of the first auxiliary heat exchanging part 41 and the second auxiliary heat exchanging part 42, the other heat is absorbed and the second heat exchanger 7 dissipates heat. The driving | operation to perform is demonstrated. As an example, a case where the second sub heat exchange unit 42 absorbs heat while defrosting the first sub heat exchange unit 41 will be described. At this time, the refrigerant is the compressor 2, the pressure switching unit 3, the second heat exchanger 7, the bypass circuit 61 and the expansion device 6, the inflow switching unit 5, the first sub heat exchange unit 41, the sub expansion device 43, The second auxiliary heat exchange unit 42, the inflow switching unit 5, the pumping switching unit 3, and the compressor 2 are distributed in this order.

  The defrosting control means 22 in the control unit 21 opens the bypass valve 62, reduces the amount of refrigerant flowing through the expansion device 6, opens the expansion device 6 fully open, and expands the refrigerant in the expansion device 6. Suppress. Then, the defrosting control means 22 in the control unit 21 closes the sub-bypass valve 45 and increases the amount of refrigerant flowing through the sub-expansion device 43 to promote expansion of the refrigerant in the sub-expansion device 43. These are also for reducing the pressure loss in the refrigerant circuit 8.

  Thus, the high-temperature refrigerant discharged from the compressor 2 is radiated by exchanging heat with the indoor air 12 in the second heat exchanger 7 to heat the room. At this time, since the refrigerant that has become a little lower temperature is not excessively expanded by the expansion device 6, at least the temperature of the indoor air 12, that is, a temperature sufficient for defrosting, is supplied to the first auxiliary heat exchange unit 41. It is distributed and defrosted. At this time, for example, the control unit 21 causes the temperature of the refrigerant flowing out of the second heat exchanger 7 (detected by the temperature detection unit 9) to be higher than the temperature of the indoor air 12 by a predetermined temperature difference (for example, 4 ° C.). Thus, the opening degree of the sub expansion device 43 is adjusted. The opening degree of the sub expansion device 43 may be uniquely determined according to the frequency of the compressor 2 and the temperature of the outdoor air 11. Then, the refrigerant which has been expanded in the auxiliary expansion device 43 and reduced in pressure and gas-liquid two-phased is absorbed by the second auxiliary heat exchanging part 42 from the outdoor air 11 and vaporized, and is sucked into the compressor 2 to be again heated and pressurized again. It becomes.

  Thus, the heat pump device 1 absorbs heat at the second sub heat exchange unit 42 and radiates heat at the second heat exchanger 7 while defrosting the first sub heat exchange unit 41, Can be continuously heated. In this defrosting heating operation, although the maximum capacity in the normal heating operation in which heat is absorbed by both the first auxiliary heat exchanging part 41 and the second auxiliary heat exchanging part 42 is not reached, the indoor temperature can be raised to some extent. For example, the need for heating at maximum capacity is low and comfort is not impaired.

(Semi-high temperature defrosting operation)
Next, a semi-high temperature defrosting operation, that is, while defrosting one of the first auxiliary heat exchanging part 41 and the second auxiliary heat exchanging part 42, the second heat exchanger 7 absorbs heat on the other side. However, the operation that absorbs heat will be described. As an example, a case where the second sub heat exchange unit 42 absorbs heat while defrosting the first sub heat exchange unit 41 will be described. At this time, the refrigerant is the compressor 2, the pressure switching unit 3, the inflow switching unit 5, the first sub heat exchange unit 41, the sub expansion device 43, the second sub heat exchange unit 42, the inflow switching unit 5, and the bypass circuit. 61, the expansion device 6, the second heat exchanger 7, the pumping switching unit 3, and the compressor 2 are distributed in this order.

  The defrosting control means 22 in the control unit 21 opens the bypass valve 62, reduces the amount of refrigerant flowing through the expansion device 6, opens the expansion device 6 fully open, and expands the refrigerant in the expansion device 6. Suppress. Then, the defrosting control means 22 in the control unit 21 closes the sub-bypass valve 45 and increases the amount of refrigerant flowing through the sub-expansion device 43 to promote expansion of the refrigerant in the sub-expansion device 43. In addition, these are also for reducing the pressure loss in the whole refrigerant circuit 8 as much as possible. The opening of the sub-expansion device 43 is uniquely determined according to the frequency of the compressor 2 and the temperature of the outdoor air 11.

  As a result, the high-temperature refrigerant discharged from the compressor 2 flows into the first sub heat exchange unit 41, and the frost adhering to the first sub heat exchange unit 41 is melted by the high-temperature refrigerant and removed. Frosted. Thereafter, the refrigerant that has been expanded in the sub-expansion device 43 and reduced in pressure to be gas-liquid two-phase is vaporized by absorbing heat from the outdoor air 11 in the second sub-heat exchanger 42. And since the vaporized refrigerant | coolant is not expanded too much with the expansion | swelling apparatus 6, it is still high temperature (however, it is about the same temperature as the outdoor air 11 which is a heat source at the maximum, and the temperature which can usually heat the indoor air 12) But not) flows into the second heat exchanger 7. At that time, since the refrigerant flows into the second heat exchanger 7 while maintaining a high temperature as compared with the high temperature defrosting operation, excessive heat absorption in the second heat exchanger 7 is suppressed. And the refrigerant | coolant which flowed out from the 2nd heat exchanger 7 is suck | inhaled by the compressor 2, and is high-temperature-high pressure again.

  Thus, in the semi-high temperature defrosting operation, unlike the defrosting heating operation, heating is not continued while defrosting, but most of the heat source necessary for defrosting is the second auxiliary heat exchange unit 42. It is covered by outdoor air 11. On the other hand, in the high temperature defrosting operation, the second auxiliary heat exchanging unit 42 is also defrosted, so the heat source necessary for defrosting is the indoor air 12 in the second heat exchanger 7. Therefore, in the semi-high temperature defrosting operation, the heat absorption from the indoor air 12 in the second heat exchanger 7 is suppressed more than in the high temperature defrosting operation. Thus, even if defrosting is necessary during normal heating operation, if the semi-high temperature defrosting operation is performed, the temperature of the indoor air 12 is suppressed from excessively decreasing, and thus comfortable. Does not impair sex.

  In addition, although the example which defrosts the 1st sub heat exchange part 41 in the defrost heating operation or the semi-high temperature defrost operation was demonstrated, by switching the inflow switching part 5, the 2nd sub heat exchange part 42 is changed. It is also possible to defrost. Furthermore, it is good also as a structure which changes suitably the defrost heating operation and a semi-high temperature defrost operation by the control part 21. FIG. For example, when the room is not sufficiently warm and the room temperature is low, the defrost heating operation is performed and the heating is continued. When the room is sufficiently warm and the room temperature is high, a semi-high temperature defrosting operation is performed to increase the defrosting capacity. Thereby, more efficient defrosting and heating operation are possible.

  Moreover, in these defrost heating operation or semi-high temperature defrost operation, the control part 21 determines completion | finish of defrost. Specifically, the threshold determination unit 23 determines whether or not the temperature of the refrigerant detected by the first temperature detection unit 41a or the second temperature detection unit 42a is equal to or higher than a predetermined threshold, When the threshold determination unit 23 determines that the temperature of the refrigerant is equal to or higher than the threshold while the end determination unit 24 defrosts the first sub heat exchange unit 41 or the second sub heat exchange unit 42. It is determined that the defrosting of the auxiliary heat exchange unit has been completed. In addition, when defrosting the 1st sub heat exchange part 41, what is necessary is just to determine with the temperature of the refrigerant | coolant detected by the 1st temperature detection part 41a, and when defrosting the 2nd sub heat exchange part 42, What is necessary is just to determine with the temperature of the refrigerant | coolant detected by the 2nd temperature detection part 42a. In addition, the defrosting end determination in the high temperature defrosting operation is performed using the temperature detection unit 10 provided between the first heat exchange unit 4 and the expansion device 6, and the refrigerant flowing out from the first heat exchange unit 4. What is necessary is just to judge by whether temperature is more than a predetermined threshold value. The predetermined threshold value is set to a temperature (for example, 3 ° C.) slightly higher than 0 ° C. as a temperature at which frost melts. This is because the temperature of the refrigerant does not become higher than the temperature at which the frost melts due to the heat of melting of the frost unless the defrosting of the auxiliary heat exchange unit is completed, and the temperature is slightly higher. This is because it takes into account the increase in the thermal resistance between the refrigerant and the frost and the change in the melting temperature of the frost due to the atmospheric pressure of the outdoor air.

  As described above, in the heat pump device 1 according to the first embodiment, the first heat exchange unit 4 installed outdoors has the first sub heat exchange unit 41, the second sub heat exchange unit 42, and the sub heat exchange unit 42. The expansion device 43 is configured. When the defrosting control means 22 defrosts the first sub heat exchange section 41 or the second sub heat exchange section 42, the pressure difference of the refrigerant flowing through the first heat exchange unit 4 is sub-expanded. Increase with device 43. Thereby, in order to defrost one of the 1st sub heat exchange part 41 and the 2nd sub heat exchange part 42, the heat pump apparatus 1 thermally radiates, and it absorbs heat from the other simultaneously.

  And even if any one of the 1st sub heat exchange part 41 and the 2nd sub heat exchange part 42 is defrosted, the 2nd heat exchanger 7 installed indoors by absorbing heat from the other. Thus, warm heat can be supplied to the indoor air 12 (defrost heating operation). Moreover, even if any one of the 1st sub heat exchange part 41 and the 2nd sub heat exchange part 42 is defrosted, the quantity absorbed by the 2nd heat exchanger 7 is absorbed by absorbing heat from the other. It can be reduced (semi-high temperature defrosting operation). Thereby, in defrost heating operation, comfort is improved dramatically, and comfort is not impaired in semi-high temperature defrost operation.

  As described above, in the defrosting heating operation, defrosting can be performed while warm heat is supplied to the room that is the heat demand section, so that user discomfort is suppressed and comfort is improved. In the defrosting heating operation, the refrigerant discharged from the compressor 2 is supplied to the second heat exchanger 7 (load heat exchanger) before the first heat exchange unit 4. Of the first heat exchange unit 4, the first sub heat exchange unit 41 or the second sub heat exchange unit 42 is defrosted using the residual heat of the refrigerant radiated by the second heat exchanger 7. . For this reason, energy efficiency is high. In the high-temperature defrosting operation and the semi-high temperature defrosting operation, the high-temperature refrigerant discharged from the compressor 2 is supplied to the first heat exchange unit 4 before the second heat exchanger 7. Although energy efficiency is not so high, it is possible to defrost at high speed.

  In addition, since only the sub-expansion device 43 is added, the defrosting heating operation and the semi-high temperature defrosting operation are realized. Therefore, the distribution route is simple, and the size and cost of the device increase with the increase in the number of devices. The rise can be suppressed. Further, the refrigerant flow path is the same in the normal heating operation and the defrosting heating operation, and is the same in the normal cooling operation and the semi-high temperature defrosting operation. For this reason, an unnecessary valve can be omitted and the site | part which a refrigerant | coolant pool generate | occur | produces can be reduced. Therefore, the refrigerant pool does not occur before and after the defrosting process, the process for eliminating the refrigerant pool is unnecessary, and the operation of the heat pump device 1 is simple. Thereby, it is allowed to lower the pressure resistance performance of the pipe, and an increase in the amount of the refrigerant can be suppressed, so that an increase in cost can be suppressed.

  Moreover, since the pressure feed switching unit 3 is provided, the flow direction of the refrigerant can be changed by the pressure feed switching unit 3. For this reason, both normal heating operation for supplying warm air to the indoor air 12 and normal cooling operation for supplying cold heat to the indoor air 12 are possible. Further, the refrigerant discharged from the compressor 2 is supplied to the second heat exchanger 7 (load heat exchanger) prior to the first heat exchange unit 4, and the second heat exchanger 7 Defrosting heating operation for defrosting the first auxiliary heat exchanging part 41 or the second auxiliary heat exchanging part 42 in the first heat exchanging unit 4 using the residual heat of the radiated refrigerant, and compression The high-temperature refrigerant discharged from the machine 2 is supplied to the first heat exchange unit 4 before the second heat exchanger 7, and the first sub heat exchange in the first heat exchange unit 4 is performed. The high temperature defrosting operation and the semi-high temperature defrosting operation in which the part 41 or the second auxiliary heat exchange unit 42 is directly defrosted with a high temperature refrigerant can be used properly.

  Furthermore, since the inflow switching unit 5 is provided, the inflow switching unit 5 can change the refrigerant flow direction in the first heat exchange unit 4. Further, the defrosting control means 22 increases the pressure difference of the sub expansion device 43 while switching the refrigerant flow direction in the inflow switching unit 5, whereby the first sub heat exchange unit 41 and the second sub heat. Of the exchange part 42, heat can be removed and defrosted to the auxiliary heat exchange part through which the refrigerant flows first, and then absorbed by the auxiliary heat exchange part through which the refrigerant flows. Furthermore, by adopting both the inflow switching unit 5 and the pressure feeding switching unit 3, the defrosting heating operation and the semi-high temperature defrosting operation are performed by the first sub heat exchange unit 41 and the second sub heat exchange. This can be done in part 42.

  Further, since the bypass circuit 61 and the bypass valve 62 are provided, the operation of closing the bypass valve 62 and increasing the refrigerant pressure difference before and after the expansion device 6, that is, normal heating operation, normal cooling operation, and An operation in which the high-temperature defrosting operation is possible and the bypass valve 62 is opened to reduce the refrigerant pressure difference before and after the expansion device 6 and increase the refrigerant pressure difference before and after the auxiliary expansion device 43, that is, Defrosting heating operation and semi-high temperature defrosting operation are possible. For this reason, the energy efficiency at the time of defrosting improves.

  Further, since the auxiliary bypass circuit 44 and the auxiliary bypass valve 45 are provided, the operation of closing the auxiliary bypass valve 45 and increasing the refrigerant pressure difference before and after the auxiliary expansion device 43, that is, the defrosting heating operation. In addition, the semi-high temperature defrosting operation is possible, and by opening the auxiliary bypass valve 45 and bypassing the auxiliary expansion device 43, the pressure difference of the refrigerant before and after the auxiliary expansion device 43 is reduced, and the first auxiliary defrosting operation is performed. An operation that absorbs or dissipates heat from both the heat exchange unit 41 and the second auxiliary heat exchange unit 42, that is, a normal heating operation, a normal cooling operation, and a high-temperature defrosting operation are possible. Thereby, the increase in the pressure loss in the 1st heat exchange unit 4 can be suppressed, and the fall of efficiency can be suppressed.

  Furthermore, since the expansion valve which adjusts the flow volume of a refrigerant | coolant and the pressure difference of a refrigerant | coolant with an opening degree is employ | adopted for the subexpansion apparatus 43, the pressure difference of the refrigerant | coolant before and behind the subexpansion apparatus 43 can be finely adjusted. . For this reason, the precision of the change of the operating condition at the time of defrosting, temperature adjustment, etc. improves.

  Furthermore, since the 1st temperature detection part 41a or the 2nd temperature detection part 42a is provided, the determination accuracy of the defrost end in a defrost heating operation and a semi-high temperature defrost operation is very high. For this reason, useless energy consumption required for defrosting can be suppressed. Moreover, the defrosting time can be suppressed, and the effect of improving comfort or reducing discomfort is further enhanced.

(Modification)
Next, a heat pump device 1 according to a modification of the first embodiment will be described. When the normal cooling operation, the high-temperature defrosting operation, and the semi-high temperature defrosting operation are unnecessary, the heat pump device 1 can perform the normal heating operation and the defrosting heating operation even if the pumping switching unit 3 is omitted. Further, when the normal heating operation and the defrosting heating operation are unnecessary, the normal cooling operation, the high temperature defrosting operation, and the semi-high temperature defrosting operation are possible even if the pumping switching unit 3 is omitted. Thus, if the kind of driving | operation is selected according to a use, the pumping switching part 3 can be omitted.

  Moreover, when it is sufficient to defrost only one of the first sub heat exchange unit 41 and the second sub heat exchange unit 42, the inflow switching unit 5 can be omitted. For example, when frost is likely to be generated in one of the first sub heat exchange unit 41 and the second sub heat exchange unit 42, either one is efficiently defrosted by high-temperature defrosting operation, and the other is It can comprise so that it may defrost, heating by defrost heating operation. Thereby, even if the inflow switching part 5 is omitted, it is possible to suppress a decrease in comfort.

  Moreover, even if the opening degree of the expansion device 6 is fully opened, the bypass circuit 61 and the bypass valve 62 can be omitted as long as the pressure loss is in an allowable range. This contributes to cost reduction. Similarly to the expansion device 6, even if the opening degree of the sub expansion device 43 is fully opened, the sub bypass circuit 44 and the sub bypass valve 45 can be omitted as long as the pressure loss is within an allowable range.

  Further, the sub-expansion device 43 may be configured by a capillary tube instead of an expansion valve that adjusts the flow rate of the refrigerant. This capillary tube does not change the opening degree like an expansion valve, and the pressure difference before and after passage is fixed in accordance with the circulation amount of the refrigerant. Thereby, in the case of defrosting heating operation, etc., since the operating conditions such as the frequency of the compressor 2 are fixed, the degree of freedom of the operating conditions and the degree of freedom of adjustment are slightly lower than the expansion valve, but at a lower cost. In addition, the same effects as those of the first embodiment can be obtained while downsizing.

  Furthermore, in the first embodiment, the configuration in which the indoor air 12 is heated or cooled by the second heat exchanger 7 in the heat demand section has been described. However, the present invention is not limited to this. It is good also as a structure to cool. In this case, the liquid heated or cooled by the second heat exchanger 7 may be used to indirectly heat or cool the room with a fan coil, radiator, floor heating, or the like disposed in the room. Good. Thus, instead of heating or cooling the indoor air 12, the heat demand unit may generate hot water, hot water for heating, cold water for cooling, or the like.

Embodiment 2. FIG.
Next, the heat pump apparatus 100 according to the second embodiment will be described. FIG. 2 is a schematic diagram showing a heat pump device 100 according to the second embodiment. The second embodiment is different from the first embodiment in that a plurality of flow paths through which the refrigerant branches and flows are formed in the first sub heat exchange section 41 and the second sub heat exchange section 42. Is different. In the second embodiment, portions common to the first embodiment are denoted by the same reference numerals, description thereof is omitted, and differences from the first embodiment will be mainly described.

  In the second embodiment, as shown in FIG. 2, a first circulation path 4 a and a second circulation path 4 b are formed in the first auxiliary heat exchanging part 41 so that the refrigerant always branches and flows in parallel. ing. The first distribution path 4a and the second distribution path 4b are also formed in the second auxiliary heat exchange unit 42 as they are. The first flow path 4a branches between the first sub heat exchange unit 41 and the second sub heat exchange unit 42, one is connected to one end of the sub expansion device 43, and the other is the first It is connected to one end of the sub bypass circuit 44a. The first flow path 4a joins again at the other end of the sub-expansion device 43 and the other end of the first sub-bypass circuit 44a. The first sub bypass circuit 44a is provided with a first sub bypass valve 45a. The first sub bypass valve 45a controls whether or not the refrigerant flows through the first sub bypass circuit 44a.

  The second flow path 4b also branches between the first sub heat exchange unit 41 and the second sub heat exchange unit 42, one of which is connected to one end of the sub expansion device 43, and the other is the second sub heat exchange unit 42. 2 is connected to one end of the secondary bypass circuit 44b. Then, the second flow path 4b joins again at the other end of the sub expansion device 43 and the other end of the second sub bypass circuit 44b. The second sub bypass circuit 44b is provided with a second sub bypass valve 45b. The second sub bypass valve 45b controls whether or not the refrigerant flows through the second sub bypass circuit 44b.

  As described above, the secondary expansion device 43 is installed at a portion where the first distribution path 4a and the second distribution path 4b merge. The first temperature detection unit 41a and the second temperature detection unit 42a are provided at both ends of the sub-expansion device 43 installed at the portion where the first flow path 4a and the second flow path 4b merge. It has been.

  The heat pump device 100 according to the second embodiment is different from the first embodiment in that a plurality of distribution paths are formed, but a normal heating operation, a normal cooling operation, a defrost heating operation, and a semi-high temperature defrost operation. The operation of the high temperature defrosting operation is the same as that of the first embodiment. Note that the first sub-bypass valve 45a and the second sub-bypass valve 45b in the second embodiment are simultaneously opened and closed at the same timing when the sub-bypass valve 45 in the first embodiment is opened and closed. The configuration adopted in the modification of the first embodiment can also be adopted in the second embodiment.

  As described above, in the second embodiment, the first flow path 4a and the second flow path through which the refrigerant branches and flows to the first sub heat exchange unit 41 and the second sub heat exchange unit 42. Since 4b is formed, the pressure loss in the 1st sub heat exchange part 41 and the 2nd sub heat exchange part 42 is reduced more. For this reason, in addition to the effect obtained in the first embodiment, the efficiency of the refrigeration cycle in the refrigerant circuit 8 can be increased.

  Further, since the first secondary bypass circuit 44a and the second secondary bypass circuit 44b are connected to the first circulation path 4a and the second circulation path 4b, respectively, bypass for bypassing the secondary expansion device 43 The function is improved and the pressure difference of the refrigerant is reduced. Further, even if the pressure difference or temperature of the refrigerant in the first circulation path 4a and the second circulation path 4b is somewhat unbalanced, the first circulation path 4a and the second circulation path are formed at both ends of the sub-expansion device 43. Since the two distribution channels 4b once join, this imbalance is corrected naturally. At that time, the first distribution path 4a and the second distribution path 4b are merged after branching to the first sub-bypass circuit 44a and the second sub-bypass circuit 44b, respectively. There is no increase in pressure loss.

  In the second embodiment, the first sub bypass valve 45a and the second sub bypass valve 45b are provided separately for the first sub bypass circuit 44a and the second sub bypass circuit 44b, respectively. Although it is a body valve, it is opened and closed simultaneously at the same timing, and even if the valve body is formed integrally or a single motor that supplies the driving power required for opening and closing is combined Good. In this case, it becomes easier to obtain the effect of downsizing or cost reduction.

  The first circulation path 4a may include a plurality of first sub bypass circuits 44a and first sub bypass valves 45a. A plurality of second sub-bypass circuits 44b and second sub-bypass valves 45b may be provided in the second flow path 4b. In the second embodiment, the same number of flow paths (the first flow path 4a and the second flow path) are used in the first sub heat exchange unit 41 and the second sub heat exchange unit 42 before and after the sub expansion device 43. However, a different number of distribution channels may be used. In this case, on the side having a small number of distribution paths before and after the secondary expansion device 43, a plurality of secondary bypass circuits are branched from at least one distribution path.

  DESCRIPTION OF SYMBOLS 1 Heat pump apparatus, 2 Compressor, 3 Pumping switching part, 4 1st heat exchange unit, 4a 1st distribution path, 4b 2nd distribution path, 5 Inflow switching part, 6 Expansion apparatus, 7 2nd heat exchange , 8 refrigerant circuit, 9 temperature detection unit, 10 temperature detection unit, 11 outdoor air, 12 indoor air, 21 control unit, 22 defrosting control unit, 23 threshold determination unit, 24 end determination unit, 41 first sub Heat exchange unit, 41a first temperature detection unit, 42 second sub heat exchange unit, 42a second temperature detection unit, 43 sub expansion device, 44 sub bypass circuit, 44a first sub bypass circuit, 44b second Sub-bypass circuit, 45 sub-bypass valve, 45a first sub-bypass valve, 45b second sub-bypass valve, 61 bypass circuit, 62 bypass valve, 100 heat pump device.

Claims (11)

A refrigerant circuit in which a compressor, a first heat exchange unit, an expansion device, and a second heat exchanger are connected by piping, and a refrigerant flows;
A control unit for controlling the operation of the refrigerant circuit,
The first heat exchange unit includes:
A plurality of auxiliary heat exchange units connected in series;
A secondary expansion device provided between the plurality of secondary heat exchange units,
The controller is
When defrosting the sub heat exchanger, the defrosting control increases the pressure difference between the refrigerant flowing upstream of the sub expansion device and the refrigerant flowing downstream of the sub expansion device by the sub expansion device. A heat pump device comprising: means. The refrigerant circuit is
The heat pump device according to claim 1, further comprising a pressure feed switching unit that switches a flow direction of the refrigerant in the refrigerant circuit. The refrigerant circuit is
The heat pump device according to claim 1, further comprising an inflow switching unit that switches a flow direction of the refrigerant in the first heat exchange unit. The refrigerant circuit is
A bypass circuit for bypassing the expansion device;
The heat pump device according to any one of claims 1 to 3, further comprising a bypass valve provided in the bypass circuit and configured to adjust a circulation amount of the refrigerant in the bypass circuit. The defrosting control means includes
The heat pump device according to claim 4, wherein the defrost valve is opened when defrosting the auxiliary heat exchange unit. The refrigerant circuit is
A sub-bypass circuit that bypasses the sub-inflator;
The heat pump device according to claim 1, further comprising: a sub bypass valve that is provided in the sub bypass circuit and adjusts a refrigerant flow rate in the sub bypass circuit. The defrosting control means includes
The heat pump device according to claim 6, wherein the sub bypass valve is closed when the sub heat exchange unit is defrosted. In the auxiliary heat exchange part,
A plurality of distribution channels through which the refrigerant branches and distributes are formed,
The heat pump device according to claim 6 or 7, wherein the sub bypass circuit and the sub bypass valve are provided for each of the plurality of flow paths. The secondary expansion device is
The heat pump device according to any one of claims 1 to 8, wherein the heat pump device includes an expansion valve that adjusts a circulation amount of the refrigerant. The secondary expansion device is
It is comprised with the capillary tube. The heat pump apparatus of any one of Claims 1-8 characterized by the above-mentioned. The refrigerant circuit is
A temperature detection unit for detecting the temperature of the refrigerant;
The controller is
Threshold determination means for determining whether the temperature of the refrigerant detected by the temperature detection unit is equal to or higher than a predetermined threshold;
An end determination for determining that the defrosting of the auxiliary heat exchange unit is completed when the threshold determination unit determines that the temperature of the refrigerant is equal to or higher than the threshold while defrosting the auxiliary heat exchange unit. The heat pump device according to claim 1, further comprising: means.

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