JP2007071478A - Heat pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump device capable of performing a heating operation even during a defrosting operation. <P>SOLUTION: As this heat pump device comprises a second evaporator 8 mounted between a first evaporator 5 and a refrigerant suction side of a compressor 1, and exchanging heat between a refrigerant flowing out from the first evaporator 5 and the air, a second expansion means 7 mounted at a refrigerant inflow side of the second evaporator 8, and a second opening/closing valve 6 capable of opening and closing a flow channel bypassing the second expansion means 7, the heat of refrigerant radiating heat in a gas cooler 2 and the first evaporator 5 can be absorbed by the second evaporator 8, thus the hot water can be supplied in the gas cooler 2 even when the first evaporator 5 is defrosted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat pump device used for hot water supply or heating.

Conventionally, as this type of heat pump device, a refrigerant circuit capable of sequentially circulating a refrigerant to a compressor, a high temperature side heat exchanger, an expansion means, and a low temperature side heat exchanger, and a part of the refrigerant discharged from the compressor, The low-temperature side heat exchanger can be defrosted by passing through the high-temperature side heat exchanger and the expansion means without being passed through the expansion means, and is compressed through the defrosting circuit. By performing a defrosting operation in which a part of the high-temperature refrigerant discharged from the machine flows into the low-temperature side heat exchanger, the frost adhering to the low-temperature side heat exchanger by the normal heating operation is melted by the high-temperature refrigerant. What was made into is known (for example, refer patent document 1).
JP 2004-294059 A

  However, in the conventional heat pump apparatus, when a part of the refrigerant discharged from the compressor through the defrosting circuit is circulated to the low temperature side heat exchanger, the heat pump cycle cannot be configured. During operation, the heating operation must be stopped. For example, when a heat pump device is used as a hot water storage water heater that uses hot water at night to boil hot water, if the defrosting operation is repeated, There was a problem that boiling water could not be completed.

  This invention is made | formed in view of the said problem, The place made into the objective is to provide the heat pump apparatus which can perform a heating operation also during a defrost operation.

  In order to achieve the above object, the present invention provides a refrigerant circuit capable of sequentially circulating a refrigerant through a compressor, a high temperature side heat exchanger, an expansion means, and a low temperature side heat exchanger, and a part of the refrigerant discharged from the compressor. In the heat pump device comprising the defrosting circuit capable of defrosting the low-temperature side heat exchanger by circulating the low-temperature side heat exchanger without passing through the high-temperature side heat exchanger and the expansion means, the low-temperature side A heat exchanger for defrost heating, which is provided between the heat exchanger and the refrigerant suction side of the compressor, and capable of exchanging heat between the refrigerant flowing out from the low temperature side heat exchanger and the air, and a heat exchanger for defrost heating And a defrosting heating expansion means capable of reducing the pressure of the refrigerant flowing into the tank to a predetermined pressure.

  Thereby, a part of the refrigerant discharged from the compressor flows through the defrosting circuit and flows into the low temperature side heat exchanger, and the refrigerant flowing out from the low temperature side heat exchanger is decompressed by the defrosting heating expansion means. Therefore, the refrigerant that has radiated heat in the high-temperature side heat exchanger and the low-temperature side heat exchanger can absorb heat in the defrost-heating heat exchanger.

  According to the present invention, the refrigerant that has dissipated heat in the high temperature side heat exchanger and the low temperature side heat exchanger can absorb heat in the heat exchanger for defrost heating. Therefore, even when the low temperature side heat exchanger is defrosted, It becomes possible to perform heating operations such as hot water supply in the side heat exchanger.

  1 to 3 show an embodiment of the present invention, FIG. 1 is a circuit diagram of a heat pump device, FIG. 2 is a circuit diagram of a heat pump device showing a hot water supply operation, and FIG. 3 is a heat pump device showing a defrosting hot water operation. FIG.

  This heat pump device is used for a heat pump unit of a heat pump type hot water heater, and includes a refrigerant circuit 10 that constitutes a heat pump cycle, and a control unit 20 that controls the operation of the heat pump unit.

  The refrigerant circuit 10 includes a compressor 1, a gas cooler 2 as a high temperature side heat exchanger, a first expansion valve 3 as expansion means, a first on-off valve 4 as refrigerant circulation means, and a first as a low temperature side heat exchanger. 1 evaporator 5, second on-off valve 6 as a bypass on-off valve, second expansion valve 7 as a defrost heating expansion means, second evaporator 8 as a defrost heating heat exchanger, removal A third on-off valve 9 is provided as a frost on-off valve, and these are connected by a refrigerant distribution pipe made of copper or stainless steel. That is, the refrigerant inflow side of the gas cooler 2 is connected to the refrigerant discharge side of the compressor 1, and the refrigerant inflow side of the first evaporator 4 is connected to the refrigerant outflow side of the gas cooler 2. A first expansion valve 3 and a first on-off valve 4 are provided in parallel between the refrigerant outflow side of the gas cooler 2 and the refrigerant inflow side of the first evaporator 4. The refrigerant inflow side of the second evaporator 8 is connected to the refrigerant outflow side of the first evaporator 5, and is between the refrigerant outflow side of the first evaporator 5 and the refrigerant inflow side of the second evaporator 8. The second on-off valve 6 and the second expansion valve 7 are provided in parallel with each other. The refrigerant suction side of the compressor 1 is connected to the refrigerant outflow side of the second evaporator 8. Further, on the refrigerant discharge side of the low-stage compression section (to be described later) of the compressor 1, the gas cooler 2, the first expansion valve 3, and the first electromagnetic valve 4 are bypassed, and the refrigerant inflow side of the first evaporator 5. A defrosting circuit 9a for circulating the refrigerant is connected to the defrosting circuit 9a, and a second on-off valve 9 is provided in the defrosting circuit 9a. Furthermore, here, carbon dioxide whose high pressure side is in a supercritical state is used as the refrigerant.

  As the compressor 1, a two-stage compressor having a low-stage compression section 1a and a high-stage compression section 1b is used, and the refrigerant sucked from the suction side of the compressor 1 is given a predetermined intermediate pressure in the low-stage compression section 1a. The refrigerant compressed to the intermediate pressure and compressed to the intermediate pressure can be compressed to a predetermined high pressure higher than the intermediate pressure in the high-stage compression section 1b. Moreover, the refrigerant | coolant inflow side of the circuit 9a for defrost mentioned above is connected to the refrigerant path between the low stage side compression part 1a of the compressor 1, and the high stage side compression part 1b.

  The gas cooler 2 has a refrigerant flow path 2a and a heated medium flow path 2b, and exchanges heat between the refrigerant and the heated medium. A hot water storage tank (not shown) is connected to the heated medium flow passage 2b by a hot water supply pipe 2c, and water in the hot water storage tank is circulated through the gas cooler 2 to be heated and stored in the hot water storage tank.

  Each of the first and second evaporators 5 and 8 is a fin tube type heat exchanger, and exchanges heat between the refrigerant and the air. The first and second evaporators 5 and 8 are provided with first and second evaporator fans 5a and 8a, respectively, for circulating air that exchanges heat with the refrigerant.

  A manual expansion valve is used for each of the first and second expansion valves 3 and 7, and the circulating refrigerant is reduced to a predetermined pressure. The first and second expansion valves 3 and 7 may be capillary tubes instead of manual expansion valves.

  A solenoid valve is used for each of the first to third on-off valves 4, 6, 9. Switching between the hot water supply operation and the defrosting hot water supply operation is performed by opening / closing the respective on-off valves 4, 6, 9. Yes.

  The control unit 20 is configured by a microcomputer, and a program related to switching control between the hot water supply operation and the defrosting hot water supply operation is stored in the memory. Further, the control unit 20 includes a first on-off valve 4, a first evaporator blower 5a, a temperature detector 5b for detecting the temperature of the first evaporator 5, a second on-off valve 6, and a third on-off valve. A valve 9 is connected.

  In the heat pump device configured as described above, when performing a normal hot water supply operation, the second on-off valve 6 is opened, the first and third on-off valves 4 and 9 are closed, and the compressor 1 The first evaporator fan 5a and the second evaporator fan 8a are operated. Thus, as shown in FIG. 2, the refrigerant discharged from the compressor 1 flows through the gas cooler 2 and then flows into the first evaporator 5 via the first expansion valve 3. Further, the refrigerant that has flowed through the first evaporator 5 flows through the second evaporator 8 via the second on-off valve 6, and then is sucked into the compressor 1. At this time, the second opening / closing valve 6 and the second expansion valve 7 are provided in parallel on the inflow side of the second evaporator 7, but compared with the opened second opening / closing valve 6. Since the flow resistance of the second expansion valve 7 is remarkably high, almost all the refrigerant flows into the second evaporator 8 through the second on-off valve 6. Due to the circulation of the refrigerant, the refrigerant discharged from the compressor 1 radiates heat in the gas cooler 2 and heats water flowing through the gas cooler 2. Moreover, the refrigerant | coolant which distribute | circulates the 1st and 2nd evaporators 5 and 8 absorbs heat in the 1st evaporator 5, evaporates, and it absorbs heat in the 2nd evaporator 8, and superheat degree increases.

  Further, if the hot water supply operation is continued, depending on the temperature and humidity conditions of the air that exchanges heat with the refrigerant in the first evaporator 5, the first evaporator 5 is frosted, so it is necessary to perform the defrost hot water supply operation. . In this case, the second on-off valve 6 is closed, the first and third on-off valves 4 and 9 are opened, the compressor 1 and the second evaporator fan 8a are operated, and the first evaporation is performed. The blower 5a for equipment is stopped. Thus, as shown in FIG. 3, the refrigerant discharged from the compressor 1 flows through the gas cooler 2 and then flows into the first evaporator 5 via the first on-off valve 4. In addition, a part of the refrigerant discharged from the low-stage compression unit 1 a of the compressor 1 flows through the defrosting circuit 9 a and flows through the gas cooler 2, the first expansion valve 3, and the first on-off valve 4. Without flowing into the first evaporator 5. Further, the refrigerant that has flowed through the first evaporator 5 flows through the second evaporator 8 via the second expansion valve 7 and is then sucked into the compressor 1. At this time, the first expansion valve 3 and the first on-off valve 4 are provided in parallel between the outflow side of the gas cooler 2 and the inflow side of the first evaporator 5. Since the flow resistance of the first expansion valve 3 is significantly higher than that of the on-off valve 4, almost all of the refrigerant flows into the first evaporator 5 through the first on-off valve 4. Due to the circulation of the refrigerant, the refrigerant discharged from the compressor 1 radiates heat in the gas cooler 2 and heats water flowing through the gas cooler 2. In addition, a part of the refrigerant discharged from the lower stage compression unit 1 a of the compressor 1 dissipates heat in the first evaporator 4 and melts frost attached to the first evaporator 5. Furthermore, the refrigerant that has dissipated heat in the gas cooler 2 and the first evaporator 5 absorbs heat in the second evaporator 8 and evaporates.

  Here, operation | movement of the control part 20 regarding the switching of hot water supply operation and defrost hot water supply operation is demonstrated using the flowchart of FIG. First, a hot water supply operation is performed (step S1), and when the detected temperature T of the temperature detector 5b becomes equal to or lower than a predetermined temperature T1 (step S2), the operation is switched to a defrosting hot water supply operation (step S3). Next, when the detected temperature T of the temperature detector 5b becomes equal to or higher than the predetermined temperature T2 (step S4), the operation is switched again to the hot water supply operation (step S1).

  Thus, according to the heat pump device of the present embodiment, the refrigerant and air that are provided between the first evaporator 5 and the refrigerant suction side of the compressor 1 and flow out of the first evaporator 5 are heated. A replaceable second evaporator 8, a second expansion means 7 provided on the refrigerant inflow side of the second evaporator 8, and a second flow path that can open and close the flow path bypassing the second expansion means 7. The on-off valve 6 is provided, so that the heat dissipated in the gas cooler 2 and the first evaporator 5 can be absorbed in the second evaporator 8, and the first evaporator 5 is defrosted. In the gas cooler 2, hot water can be supplied.

  In addition, since the hot water supply operation and the defrost hot water supply operation are switched according to the detected temperature T of the temperature detector 5b, the frost formation of the first evaporator 5 is detected and the defrost hot water supply operation is performed. It is possible to detect the melting and perform a hot water supply operation, and to reliably prevent a decrease in the heat exchange capability of the first evaporator 5.

  Since the first on-off valve 4 capable of opening and closing the bypass passage of the first expansion valve 3 is provided for the refrigerant flowing out of the gas cooler 2, the first evaporator 5 is not decompressed without reducing the refrigerant flowing out of the gas cooler 2. By keeping the temperature of the first evaporator 5 at a high temperature in the defrosting hot water supply operation, the frost can be surely melted.

  Further, as the compressor 1, a two-stage compressor having a low-stage compression section 1a that compresses the sucked refrigerant to a predetermined intermediate pressure and a high-stage compression section 1b that compresses the refrigerant compressed to the intermediate pressure to a predetermined high pressure. Since a part of the refrigerant compressed to the intermediate pressure in the low-stage compression unit 1a is circulated through the defrosting circuit 9 using the compressor, the refrigerant having the intermediate pressure lower than the discharge pressure of the compressor 1 is the first. And it can be made to flow into the 2nd evaporators 4 and 7, and the shortage of the amount of refrigerant circulation by the balance of the pressure in a circuit breaking can be prevented.

  In addition, since carbon dioxide whose high pressure side is in a supercritical state is used as the refrigerant, it is possible to reduce environmental loads such as ozone layer destruction and global warming.

  In the embodiment, as the compressor 1, the low-stage compression unit 1a that compresses the sucked refrigerant to a predetermined intermediate pressure, and the high-stage compression unit that compresses the refrigerant compressed to the intermediate pressure to a predetermined high pressure. A two-stage compressor having 1b was used, and a part of the refrigerant compressed to an intermediate pressure in the low-stage compression unit 1a was circulated through the defrosting circuit 9, but as shown in FIG. Even when a part of the refrigerant discharged from the compressor is circulated through the defrosting circuit 9a using the single-stage compressor 11, hot water is supplied in the gas cooler 2 and the first evaporation is performed as in the above embodiment. The defrosting of the vessel 5 can be performed.

  Moreover, in the said embodiment, the thing which provided the 1st on-off valve 4 and the 2nd on-off valve 6 in parallel with the 1st expansion valve 3 and the 2nd expansion valve 7 with a fixed valve opening degree respectively is shown. However, as shown in FIG. 6, by using an electronic expansion valve with variable valve opening as the first expansion valve 12 and the second expansion valve 13, the first on-off valve 4 and the second on-off valve 6 The pressure of the refrigerant flowing through the refrigerant circuit 10 can be adjusted without the need for

Schematic configuration diagram of heat pump device Schematic configuration diagram of heat pump device showing hot water supply operation Schematic configuration diagram of heat pump device showing defrosting hot water operation Flow chart showing switching control between hot water supply operation and defrost hot water supply operation Schematic configuration diagram of heat pump device showing other examples Schematic configuration diagram of heat pump device showing other examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Compressor, 1a ... Low stage side compression part, 1b ... High stage side compression part, 2 ... Gas cooler, 3 ... 1st expansion valve, 4 ... 1st on-off valve, 5 ... 1st evaporator, 5b DESCRIPTION OF SYMBOLS ... Temperature detector, 6 ... 2nd on-off valve, 7 ... 2nd expansion valve, 8 ... 2nd evaporator, 9 ... 3rd on-off valve, 9a ... Circuit for defrosting, 10 ... Refrigerant circuit, 11 Compressor, 12 Electronic expansion valve, 13 Electronic expansion valve, 20 Control unit.

Claims (7)

Refrigerant circuit capable of sequentially flowing refrigerant to the compressor, high temperature side heat exchanger, expansion means and low temperature side heat exchanger, and a part of the refrigerant discharged from the compressor is distributed to high temperature side heat exchanger and expansion means In the heat pump device provided with a circuit for defrosting capable of defrosting the low-temperature side heat exchanger by distributing it to the low-temperature side heat exchanger without causing
A heat exchanger for defrosting heating provided between the low temperature side heat exchanger and the refrigerant suction side of the compressor, and capable of exchanging heat between the refrigerant flowing out of the low temperature side heat exchanger and the air;
A heat pump device comprising: defrost heating expansion means capable of reducing the pressure of the refrigerant flowing into the defrost heating heat exchanger to a predetermined pressure. A defrosting on-off valve capable of opening and closing the defrosting circuit;
A temperature detector for detecting the temperature of the low temperature side heat exchanger;
The refrigerant discharged from the compressor is caused to flow through the high-temperature side heat exchanger and the expansion means by closing the defrosting on-off valve and flow into the low-temperature side heat exchanger, and the refrigerant flowing out from the low-temperature side heat exchanger A heating operation for flowing the pressure into the heat exchanger for defrost heating without reducing the pressure to a predetermined pressure by the expansion means for defrost heating, and opening the defrost on-off valve for a part of the refrigerant discharged from the compressor By flowing into the low-temperature side heat exchanger through the defrosting circuit, the other refrigerant flows into the low-temperature side heat exchanger through the high-temperature side heat exchanger and the expansion means, and the low-temperature side heat exchanger Switching control for switching the defrosting heating operation in which the pressure of the refrigerant flowing out of the refrigerant is reduced to a predetermined pressure by the defrosting heating expansion means and flows into the defrosting heat exchanger according to the temperature detected by the temperature detector Characterized by comprising means The heat pump device according to claim 1. The heat pump device according to claim 1 or 2, further comprising refrigerant circulation means for causing the refrigerant flowing out from the high temperature side heat exchanger to flow through the low temperature side heat exchanger without being depressurized by the expansion means. The compressor includes a low-stage compression unit that compresses the sucked refrigerant to a predetermined intermediate pressure, and a high-stage compression unit that compresses the refrigerant compressed to the intermediate pressure to a predetermined pressure higher than the intermediate pressure. Using a stage compressor,
4. The heat pump device according to claim 1, wherein the defrosting circuit is configured such that a part of the refrigerant compressed to an intermediate pressure flows in the low-stage compression unit. The defrosting heating expansion means includes an expansion valve or capillary tube for reducing the pressure of the refrigerant flowing into the defrosting heat exchanger to a predetermined pressure, a bypass circuit capable of bypassing the expansion valve or capillary tube, and a bypass The heat pump device according to claim 1, 2, 3, or 4, wherein the heat pump device comprises a bypass on-off valve capable of opening and closing the circuit. The heat pump device according to claim 1, 2, 3, or 4, wherein an electronic expansion valve capable of arbitrarily setting a valve opening is used as the defrosting heating expansion means. The heat pump apparatus according to claim 1, 2, 3, or 4, wherein carbon dioxide whose high pressure side is in a supercritical state is used as the refrigerant.

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