JP2004340531A - Heat pump equipment - Google Patents

Abstract

An object of the present invention is to provide a heat pump device capable of quickly performing a defrosting operation.
The refrigerant includes a normal circuit in which a compressor, a gas cooler, an expansion valve, and a heat exchanger are annularly connected to circulate the refrigerant in this order, a switching valve, and a defrosting decompression device. One end of the pipe is connected to a refrigerant pipe between the compressor 11 and the gas cooler 12, and the other end is connected to a refrigerant pipe between the expansion valve 13 and the heat exchanger 14, so that the compressor 11, the on-off valve 15, the defrost A defrost circuit in which refrigerant circulates in the order of the pressure reducing device 16 and the heat exchanger 14, and a defrost control device 17 that opens the on-off valve 15 to defrost the heat exchanger 14 during the defrost operation. In addition, since the normal operation and the defrosting operation can be quickly switched by opening and closing the on-off valve 15, a heat pump device capable of performing a high-efficiency normal operation with a reduced defrosting operation time can be provided.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat pump device capable of performing defrost.
[0002]
[Prior art]
As a conventional heat pump device, there is one provided in a heat pump hot water supply device shown in FIG. 3 (see Patent Document 1). In this heat pump type hot water supply apparatus, a compressor 1, a hot water supply heat exchanger 2 as a gas cooler, an electric expansion valve 3, an outdoor heat exchanger 4, and an accumulator 5 are connected so as to sequentially form a closed circuit. Reference numeral 6 denotes a hot water storage tank, and reference numeral 7 denotes a pump that conveys water in the hot water storage tank 6 to the hot water supply heat exchanger 2.
[0003]
The operation of the heat pump water heater configured as above will be described below. During a hot water supply operation (hereinafter referred to as a normal operation), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 exchanges heat with water in a hot water storage tank 6 carried by a pump 7 in a hot water supply heat exchanger 2 to be cooled. Then, the refrigerant becomes a low-temperature and low-pressure gas-liquid two-phase refrigerant in the electric expansion valve 3, absorbs heat from outdoor air in the outdoor heat exchanger 4, evaporates, and returns to the compressor 1 via the accumulator 5. On the other hand, the water in the hot water storage tank 6 is conveyed to the hot water supply heat exchanger 2 by the pump 7, and exchanges heat with the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 in the hot water supply heat exchanger 2 to reach a high temperature (65 degrees to 65 degrees). (About 90 degrees) and returned to the hot water storage tank 6. However, if the normal operation is continued at a low outdoor temperature in winter, frost adheres to the outdoor heat exchanger 4 and the hot water supply capacity and efficiency are reduced, so that a defrosting operation is required.
[0004]
During the defrosting operation, the valve opening of the electric expansion valve 3 is opened larger than during the normal operation. Therefore, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 4 and adheres to the outdoor heat exchanger 4 at a relatively high temperature without being decompressed as in the normal operation. Melt the frost and return to the compressor 1 via the accumulator 5. Then, after the defrosting operation is completed, the normal operation is restarted.
[0005]
As described above, according to the present invention, the normal operation and the defrosting operation can be performed without adding a component such as a special refrigerant pipe or valve for the defrosting operation.
[0006]
[Patent Document 1]
Japanese Patent No. 3297657
[Problems to be solved by the invention]
However, in the conventional configuration, an operation of opening the opening of the electric expansion valve 3 at the start of the defrosting operation is performed. However, since the normal valve opening operation speed is about 4 to 10 pulses per second, this operation is not performed. It may take tens of seconds. Therefore, a loss of switching time between the normal operation and the defrosting operation occurs. Generally, in a heat pump type hot water supply device having a hot water storage tank 6, normal (hot water supply) operation is performed using inexpensive midnight power, and in the winter season (outside air temperature is about 5 degrees or less) where defrosting operation is required, the hot water storage tank is used. It takes about 8 hours to boil all the water in 6. Assuming that the defrosting operation occurs once an hour, there is a problem that the loss of the switching time between the normal operation and the defrosting operation cannot be ignored and the efficiency of the normal operation decreases.
[0008]
An object of the present invention is to solve the conventional problems, and to provide a heat pump device capable of performing high-efficiency normal operation by shortening the defrost operation time by quickly switching between the normal operation and the defrost operation. And
[0009]
[Means for Solving the Problems]
In order to solve the conventional problem, the heat pump device of the present invention includes a defrost circuit including an on-off valve and a defrosting decompression device in addition to a normal circuit capable of normal operation. Since the switching between the normal operation and the defrosting operation can be quickly performed by opening and closing, a high-efficiency normal operation with a reduced defrosting operation time can be performed.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The invention according to claim 1 is a refrigerant pipe comprising a normal circuit in which a compressor, a gas cooler, an expansion valve, and a heat exchanger are connected in a ring and refrigerant circulates in this order, an on-off valve, and a defrosting decompression device. Is connected to a refrigerant pipe between the compressor and the gas cooler, and the other end is connected to a refrigerant pipe between the expansion valve and the heat exchanger, so that the compressor, the on-off valve, and the defrost A decompression device, a defrost circuit in which refrigerant circulates in the order of the outdoor heat exchanger, and a defrost control device that opens the on-off valve during defrost operation to perform defrost on the heat exchanger, Since the normal operation and the defrosting operation can be promptly switched by opening and closing the on-off valve, a high-efficiency normal operation in which the defrosting operation time is shortened becomes possible.
[0011]
The invention described in claim 2 is a defrosting device for defrost according to claim 1 which is a relatively inexpensive capillary tube, and is a low-cost, high-efficiency, normal-time defrosting operation time. Can drive.
[0012]
According to the third aspect of the present invention, the inner diameter of the capillary tube according to the second aspect is set to be 1.3 mm or more and 2.0 mm or less, thereby preventing the capillary tube from being blocked by sludge or the like in the refrigerant pipe. The pressure of the refrigerant pressure suitable for the defrosting operation can be reduced, and the reliability of the system is improved.
[0013]
According to a fourth aspect of the present invention, in particular, the defrosting pressure reducing device according to the first aspect is an electric expansion valve capable of controlling a refrigerant flow rate, and the outside air temperature and the amount of frost formed on the outdoor heat exchanger. By performing the refrigerant flow rate control during the defrosting operation according to such conditions, the defrosting operation time can be shortened as compared with the capillary tube.
[0014]
The invention according to claim 5 is, in particular, in the invention according to claims 1 to 4, wherein the refrigerant circulation circuit is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure, and the refrigerant is pressurized to the critical pressure or higher. By heating the water or air in the gas cooler, the refrigerant in the gas cooler is pressurized to a critical pressure or higher, so that heat is taken away by the water or air in the gas cooler and condenses even if the temperature decreases. Absent. Therefore, it is easy to form a temperature difference between the refrigerant and water or air in the entire area of the gas cooler, so that hot water or air can be obtained, and the heat exchange efficiency can be increased.
[0015]
The invention according to claim 6 uses carbon dioxide as the refrigerant to be used, and uses a relatively inexpensive and stable carbon dioxide as the refrigerant to reduce product cost and improve reliability. Can be done. In addition, carbon dioxide has an ozone depletion potential of zero, and a global warming potential that is very low, approximately 1 / 700th of that of the alternative refrigerant HFC-407C. Therefore, it is possible to provide products that are environmentally friendly.
[0016]
【Example】
Hereinafter, embodiments of a heat pump device according to the present invention will be described with reference to the drawings.
[0017]
(Example 1)
FIG. 1 is a configuration diagram of a heat pump device according to a first embodiment of the present invention. In FIG. 1, a compressor 11, a gas cooler 12, an electric expansion valve 13, and an outdoor heat exchanger 14 are sequentially connected so as to form a closed circuit, and constitute a normal circuit. Here, the gas cooler 12 is a refrigerant-to-water heat exchanger for the purpose of supplying hot water, and is hereinafter referred to as a hot water supply heat exchanger 12. One end of a refrigerant pipe composed of an on-off valve 15 and a defrosting decompression device 16 is connected to one end of a refrigerant pipe between the compressor 11 and the hot water supply heat exchanger 12, and the other end is connected to the electric expansion valve 13 and the outdoor heat exchanger 14. To form a defrost circuit in which the refrigerant circulates in the order of the compressor 11, the on-off valve 15, the defrosting decompression device 16, and the outdoor heat exchanger 14. In this embodiment, a capillary tube is used as the defrosting pressure reducing device 16. The capillary tube cannot control the flow rate of the refrigerant arbitrarily, but has the merit that the cost can be reduced because it is inexpensive. In addition, if the inner diameter of the capillary tube is small, foreign matter or the like is clogged in the capillary tube and the refrigerant circuit is closed, and if the inner diameter is large, a problem that a predetermined depressurizing effect cannot be obtained occurs. It is good to be 1.3 mm or more and 2.0 mm or less. Reference numeral 17 denotes a defrost control device, which switches between a normal (hot water supply) operation and a defrost operation by opening and closing the on-off valve 15. 18 is a heat pump unit, 19 is a temperature sensor for detecting the temperature of the refrigerant at the outlet of the outdoor heat exchanger 14, and 20 is an outdoor fan.
[0018]
Reference numeral 21 denotes a hot water storage tank, and reference numeral 22 denotes a pump that conveys water in the hot water storage tank 21 to the hot water supply heat exchanger 12 during a hot water supply operation.
[0019]
The operation of the heat pump device configured as described above will be described below. First, during normal operation, the refrigerant flows in the direction indicated by the solid arrow in FIG. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 is cooled in the hot water supply heat exchanger 12 by exchanging heat (heating the water) with water in the hot water storage tank 21 transported by the pump 22, and thereafter, is electrically expanded. The pressure is reduced by the valve 13 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. The refrigerant absorbs heat from outdoor air in the outdoor heat exchanger 14 and evaporates, and returns to the compressor 11. On the other hand, the water in the hot water storage tank 21 is transported to the hot water supply heat exchanger 12 by the pump 22, and in the hot water supply heat exchanger 12, heat exchanges with the high-temperature and high-pressure gas refrigerant discharged from the compressor 11 to achieve a high temperature (65 ° C to 65 ° C). (About 90 degrees) and returned to the hot water storage tank 21.
[0020]
Next, the defrosting operation will be described. If the normal operation is continued, frost is formed on the outdoor heat exchanger 14 to lower the hot water supply capacity, so that a defrosting operation is required. Therefore, when the refrigerant temperature at the outlet of the outdoor heat exchanger 14 detected by the temperature sensor 19 becomes equal to or lower than a predetermined value, the opening / closing valve 15 is opened by the defrost control device 17, and the refrigerant flow path from the normal circuit to the defrost circuit is switched. Is switched. During the defrosting operation, the refrigerant flows in the direction indicated by the dashed arrow in FIG. The high-temperature gaseous refrigerant discharged from the compressor 11 flows into the outdoor heat exchanger 14 through the on-off valve 15 and the defrosting decompression device 16, and the frost and heat adhering to the surface of the outdoor heat exchanger 14 here. It exchanges and defrosts, and returns to the compressor 11. When the temperature detected by the temperature sensor 19 becomes equal to or higher than a predetermined value, the on-off valve 15 is closed by the defrost control device 17, and the refrigerant flow path is switched from the defrost circuit to the normal circuit.
[0021]
As described above, in this embodiment, since the normal operation and the defrosting operation can be quickly switched by opening and closing the on-off valve 15, the high-efficiency normal operation in which the defrosting operation time is shortened becomes possible.
[0022]
(Example 2)
FIG. 2 is a configuration diagram of a heat pump device according to a second embodiment of the present invention. The components having the same structure as that of the heat pump device according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0023]
In FIG. 2, a point different from the configuration of the first embodiment is that an electric defrosting electric expansion valve 23 is provided as a defrosting decompression device. Since the refrigerant flow rate during the defrosting operation can be controlled by changing the opening degree of the electric defrosting expansion valve 23, the capillary tube is controlled by the refrigerant flow rate control according to conditions such as the outside air temperature and the amount of frost formed in the outdoor heat exchanger. Thus, the defrosting operation time can be shortened.
[0024]
As the refrigerant, Freon gas, ammonia, hydrocarbon (propane, butane, etc.), carbon dioxide, etc. can be used.
[0025]
If the refrigerant circulation circuit is a supercritical heat pump cycle in which the pressure of the refrigerant is equal to or higher than the critical pressure, the water in the hot water supply heat exchanger 12 is heated by the refrigerant pressurized to the critical pressure or higher. Since the refrigerant in the refrigerant 12 is pressurized to the critical pressure or higher, the refrigerant is not condensed even if the temperature of the refrigerant is reduced by the water in the hot water supply heat exchanger 12. Therefore, it is easy to form a temperature difference between the refrigerant and the water in the entire area of the hot water supply heat exchanger 12, so that high-temperature hot water (about 90 degrees) can be obtained and the heat exchange efficiency can be increased.
[0026]
In particular, the carbon dioxide refrigerant is relatively inexpensive and stable, so that the product cost can be suppressed and the reliability can be improved. In addition, carbon dioxide has an ozone depletion potential of zero, and a global warming potential that is very low, approximately 1 / 700th of that of the alternative refrigerant HFC-407C. Therefore, it is possible to provide products that are environmentally friendly.
[0027]
Further, in this embodiment, a refrigerant-to-water heat exchanger for hot water supply is used as the gas cooler 12, but if a refrigerant-to-air heat exchanger is used as the gas cooler 12, it is applied to a heat pump air conditioner (heating machine). It is also possible.
[0028]
【The invention's effect】
As described above, according to the present invention, since the normal operation and the defrosting operation can be quickly switched, a high-efficiency normal operation in which the defrosting operation time is shortened becomes possible.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump device according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a heat pump device according to a second embodiment of the present invention. FIG. 3 is a configuration diagram of a conventional heat pump device.
DESCRIPTION OF SYMBOLS 11 Compressor 12 Hot water supply heat exchanger 13 Electric expansion valve 14 Outdoor heat exchanger 15 On-off valve 16 Defrosting decompression device 17 Defrost control device 18 Heat pump unit 19 Temperature sensor 20 Outdoor fan 21 Hot water storage tank 22 Pump 23 Electric for defrost Expansion valve

Claims (6)

A compressor, a gas cooler, an expansion valve, and a heat exchanger are connected in a ring shape and a normal circuit in which the refrigerant circulates in this order, and one end of a refrigerant pipe including an on-off valve and a defrosting pressure reducing device are connected to the compressor and the gas cooler. The other end of the compressor is connected to a refrigerant pipe between the expansion valve and the heat exchanger, and the compressor, the on-off valve, the defrosting decompression device, and the heat exchanger are connected to each other. A heat pump device comprising: a defrost circuit in which refrigerant is circulated in order; and a defrost control device that opens the on-off valve to perform defrost on the outdoor heat exchanger during a defrost operation. The heat pump device according to claim 1, wherein the defrosting decompression device is a capillary tube. The heat pump device according to claim 2, wherein the inner diameter of the capillary tube is 1.3 mm or more and 2.0 mm or less. The heat pump device according to claim 1, wherein the defrost pressure reducing device is an electric expansion valve. The normal circuit is a supercritical heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure, and heats water or air in the gas cooler with the refrigerant pressurized to the critical pressure or higher. 3. The heat pump device according to 1. The heat pump device according to any one of claims 1 to 5, wherein the refrigerant is carbon dioxide.

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