JP2004061023A - Heat pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump device capable of securing the reliability of a compressor and maintaining a uniform performance factor. <P>SOLUTION: A refrigerant liquid tank 9 is installed and bypassed between an indoor heat exchanger 4 and an outdoor heat exchanger 7. Refrigerant vapor vaporized by a capillary tube 13 built in the refrigerant liquid tank 9 is joined with an outlet conductor of the heat exchanger, the refrigerant liquid cooled by the refrigerant liquid tank 9 is expanded, and then it is joined with a suction conductor 8e and sucked in the compressor 2. By this, a compression ratio of the compressor 2 can be adjusted to a set value during operation in a set pressure or more. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat pump device, and more particularly, to a heat pump compression ratio adjusting device.
[0002]
[Prior art]
The heat pump device operates in a reverse Carnot cycle. As shown in FIG. 1, the basic refrigeration circuit 1 of the cycle includes a compressor 2, a four-way valve 3, an indoor heat exchanger 4, a cooling expansion valve 5, a heating expansion valve 6, an outdoor heat exchanger 7, and The four-way valve 3 is sequentially connected by conduits 8a, 8b, 8c, and 8d, and the four-way valve 3 and the compressor 2 are connected by a suction conduit 8e.
[0003]
In the heat pump device, during the heating operation, when the four-way valve 3 is operated so that the refrigerant flows in the direction indicated by the solid line arrow, the high-temperature and high-pressure refrigerant vapor compressed by the compressor 2 generates indoor heat acting as a condenser. The condensed heat is exchanged with the exchanger 4, the condensed heat is exchanged with a fluid such as air or water to perform indoor heating, hot water generation, drying function, and the like. After being expanded by the heating expansion valve 6, the outdoor heat exchanger 7 acting as an evaporator absorbs the heat of evaporation from the heat source fluid to become low-temperature, low-pressure refrigerant vapor, and then passes through the suction conduit 8e to the compressor. 2 and the cycle is repeated.
[0004]
In the cooling operation, when the four-way valve 3 is operated so that the refrigerant flows in the direction of the dashed arrow, the high-temperature and high-pressure refrigerant vapor compressed by the compressor 2 causes the outdoor heat exchanger 7 to function as a condenser. The high-temperature and high-pressure refrigerant liquid condensed in the outdoor heat exchanger 7 expands in the expansion valve 5 for cooling, and then absorbs the heat of evaporation from the surroundings in the indoor heat exchanger 4 acting as an evaporator. After performing a cooling function, the refrigerant becomes low-temperature and low-pressure refrigerant vapor, and is sucked into the compressor 2 to repeat the cycle.
[0005]
On the other hand, in the heat pump apparatus, the larger the amount of heat released by the refrigerant in the indoor heat exchanger 4 acting as a condenser during the heating operation, the larger the deposition coefficient becomes, and during the cooling operation, the heat pump apparatus acts as an evaporator. The larger the amount of heat absorbed by the refrigerant in the indoor heat exchanger 4 to be performed, the larger the deposition coefficient. Therefore, in the heating operation, when the amount of heat released from the refrigerant is increased in the indoor heat exchanger 4 acting as a condenser in order to increase the product coefficient, the discharge temperature of the refrigerant vapor in the compressor increases, When the outside air temperature decreases, the amount of heat absorbed by the outdoor heat exchanger 7 acting as an evaporator decreases in proportion to the decrease in the outside air temperature, and the compression ratio of the compressor 2 increases. In the cooling operation, when the outside air temperature is high, if the condensation of the refrigerant vapor in the outdoor heat exchanger 7 acting as a condenser is not complete, the difference between the condensation temperature and the evaporation temperature increases, The compression ratio of the compressor increases.
[0006]
As described above, when the compression ratio of the compressor increases, the temperature of the refrigerant vapor after compression increases, causing overheating of the compressor and deterioration of the lubricating oil, thereby not only reducing the reliability of the compressor but also improving the volumetric efficiency. Phenomena such as a decrease in compression efficiency occur, and the product coefficient decreases. To prevent this, usually a compressor is provided with a high-pressure protection switch or an inverter-type compressor is used. The compression ratio is adjusted by keeping the compressor speed low.
[0007]
[Problems to be solved by the invention]
However, in the compression ratio adjusting method, when the outside air temperature is 5 ° C. or more, the compression ratio is well adjusted, and the product volume coefficient does not greatly decrease. However, it is impossible to completely prevent frost formation on the outdoor heat exchanger 7 even if the defrosting means installed near the outdoor heat exchanger 7 is operated. Since the amount of frost increases, there is a problem in that the evaporation efficiency of the refrigerant liquid in the outdoor heat exchanger 7 is reduced, and if it is severe, the operation cannot be performed.
[0008]
An object of the present invention is to solve the above problems and to provide a heat pump device capable of ensuring the reliability of a compressor and maintaining a uniform product coefficient.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a compressor, a four-way valve, an indoor heat exchanger, a cooling expansion valve, a heating expansion valve, an outdoor heat exchanger, and connecting the four-way valve to conduits 8a, 8b, 8c, 8d. In the basic refrigeration circuit in which the four-way valve and the compressor are connected by a suction pipe, a bypass pipe is connected between the cooling expansion valve and the heating expansion valve installed in the pipe 8c and the suction pipe, A refrigerant liquid tank installed in the bypass conduit, a pressure control valve and a solenoid valve respectively installed on the inlet side and the outlet side of the refrigerant liquid tank in the bypass conduit, and a second bypass conduit between the conduit 8b and the conduit 8d And a number of capillaries connected between the second bypass conduit and a branch pipe branched from the outlet side of the pressure regulating valve of the bypass conduit and incorporated in the refrigerant liquid tank. Things.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a configuration diagram of an embodiment of the present invention. In the figure, reference numeral 1 denotes a basic refrigeration circuit. The basic refrigeration circuit 1 includes a compressor 2, a four-way valve 3, an indoor heat exchanger 4, a cooling expansion valve 5, a heating expansion valve 6, an outdoor heat exchanger 7, and the four-way valve 3 connected to conduits 8a, 8b, 8c. , 8d, and the four-way valve 3 and the compressor 2 are connected by a suction conduit 8e so that the indoor heat exchanger 4 functions as a condenser during the heating operation and as an evaporator during the cooling operation. The exchanger 7 functions as an evaporator during the heating operation and as a condenser during the cooling operation.
[0011]
As the heat exchange fluid of the indoor heat exchanger 4 and the outdoor heat exchanger 7, water or air is selectively used, or water and air are used together.
[0012]
Reference numeral 9 denotes a refrigerant liquid tank. The refrigerant liquid tank 9 is provided between the cooling expansion valve 5 and the heating expansion valve 6 of the conduit 8c and a bypass conduit 10 connected to the suction conduit 8e and installed in the middle thereof. The outlet side of the refrigerant liquid tank 9 was a capillary tube 10a.
[0013]
Reference numerals 11 and 12 denote a pressure control valve and a solenoid valve, respectively. The pressure control valve 11 and the solenoid valve 12 were installed on the inlet side and the outlet side of the refrigerant liquid tank 9 of the bypass conduit 10, respectively.
[0014]
Reference numeral 13 denotes a capillary tube. The capillary tube 13 is built in the refrigerant liquid tank 9, the inlet of the capillary tube 13 is branched from the outlet side of the pressure control valve 11 of the bypass conduit 10, and the outlet is connected to the conduit 8 b and the conduit 8 d. The branch pipe 14 is further provided with an expansion valve 15 connected to a second bypass conduit 16 provided therebetween.
[0015]
A pressure (temperature) sensor 17 is installed at the inlet side of the pressure control valve 11 of the bypass conduit 10, and one of the pressure control valve 11 and the solenoid valve 12 is selectively opened and closed by an output signal of the pressure sensor. When the pressure applied to the conduit 10 is equal to or higher than a set pressure (for example, R-22 is used as a refrigerant and the heating operation is 18 to 21 kg / cm ² ), the pressure control valve 11 is opened and the solenoid valve 12 is closed. When the pressure is equal to or lower than the set pressure, it opens and closes in a manner opposite to the above.
[0016]
Unexplained reference numerals 18, 19, 20, 21 are check valves.
In the above-described present invention, when the four-way valve 3 is operated so that the refrigerant flows in the direction of the solid line arrow during the heating operation, the high-temperature and high-pressure refrigerant vapor compressed by the compressor 2 is applied to the indoor chamber that functions as a condenser. The refrigerant is condensed in the heat exchanger 4, and the condensed heat is exchanged with the fluid to perform indoor heating, hot water generation, drying function, etc., and the high-temperature and high-pressure refrigerant liquid condensed in the indoor heat exchanger 4 is expanded for heating. After expansion by the valve 6, the outdoor heat exchanger 7 acting as an evaporator absorbs heat of evaporation from the fluid and evaporates to become low-temperature and low-pressure refrigerant vapor, which is then transmitted to the compressor 2 via the suction conduit 8e. When the refrigerant is sucked and the above cycle is repeated and the four-way valve 3 is operated so that the refrigerant flows in the direction of the dashed arrow in the cooling operation, the high-temperature and high-pressure refrigerant vapor compressed by the compressor 2 acts as a condenser. In the outdoor heat exchanger 7 The high-temperature and high-pressure refrigerant liquid condensed and condensed in the outdoor heat exchanger 7 expands in the cooling expansion valve 5 and then absorbs evaporation heat from the surrounding fluid in the indoor heat exchanger 4 acting as an evaporator. After performing a cooling function to convert the refrigerant into low-temperature and low-pressure refrigerant vapor, the refrigerant is sucked into the compressor 2 via the suction conduit 8e and the above cycle is repeated. This is the same as the conventional one.
[0017]
When the heating or cooling operation is performed by such a cycle, the amount of heat absorbed by the outdoor heat exchanger 7 acting as an evaporator is small, or the refrigerant vapor is not completely condensed in the outdoor heat exchanger 7 acting as a condenser. For the reason, when the compression ratio of the compressor 2 increases, the pressure of the refrigerant liquid flowing through the conduit 8c increases. However, when the pressure is equal to or higher than the set pressure, the refrigerant liquid is supplied to the inlet side of the pressure regulating valve 11 of the bypass conduit 10. The installed pressure sensor 17 detects the pressure and transmits an output signal to the pressure control valve 11 and the solenoid valve 12, and the pressure control valve 11 receiving the output signal is opened and the opened solenoid valve 12 is closed. Is done.
[0018]
When the pressure control valve 11 is opened in this manner, a part of the refrigerant liquid flowing through the conduit 8c flows into the refrigerant liquid tank 9 via the bypass conduit 10, and another part passes through the branch pipe 14. By performing heat exchange with the refrigerant liquid flowing into the refrigerant liquid tank 9 while reducing and expanding the pressure in the capillary tube 13, the refrigerant liquid passing through the capillary tube 13 becomes refrigerant vapor, and the refrigerant liquid flowing into the refrigerant liquid tank 9 is cooled. You.
[0019]
During the heating operation, the refrigerant vapor generated while passing through the capillary 13 is used as the second bypass conduit 16 and the check valve 20 (the check valve 21 is a high-temperature high-pressure refrigerant vapor compressed by the compressor 2). The refrigerant is vaporized in the outdoor heat exchanger 7 via the conduit 8d and is sucked into the compressor 2 through the conduit 8d. In the cooling operation, the second bypass conduit 16 and the check valve 21 are closed. Is sucked into the compressor 2 via the conduit 8b together with the refrigerant vapor evaporated in the indoor heat exchanger 4 via the heat exchanger 4, thereby reducing the compression ratio of the compressor 2.
[0020]
On the other hand, when the compression ratio of the compressor 2 is reduced as described above and the pressure of the refrigerant flowing through the conduit 8c returns to or below the set pressure, the output signal of the pressure sensor 17 is stopped, so that the pressure control valve 11 is closed and the solenoid is closed. The valve 12 is opened, and the refrigerant liquid cooled in the refrigerant liquid tank 9 is expanded by the capillary tube 10a of the bypass conduit 10 and then mixed with refrigerant vapor passing through the suction conduit 8e to be sucked into the compressor 2.
[0021]
When the compression ratio of the compressor 2 is reduced as described above, the refrigerant liquid is decompressed / expanded only by the capillary 13. However, when the decompression / expansion is not sufficient by the capillary 13 alone, the expansion valve of the branch pipe 14 is used. If the degree of superheat is further adjusted by adjusting No. 15, the evaporation of the refrigerant liquid can be improved.
[0022]
【The invention's effect】
As described above, according to claim 1 of the present invention, a refrigerant liquid tank is installed between an indoor heat exchanger and an outdoor heat exchanger so as to be bypassed, and a capillary tube is built in the refrigerant liquid tank. The refrigerant vapor evaporated in the capillary tube is merged with the outlet conduit of the heat exchanger acting as an evaporator, and the refrigerant liquid cooled in the refrigerant liquid tank is expanded and then merged into the suction conduit so as to be sucked into the compressor. In addition, since the compression ratio of the compressor can be adjusted to the set value at the time of operation at or above the set pressure, the reliability of the compressor can be secured, and the appropriate refrigerant amount can be maintained regardless of the season, In particular, the efficiency of the compressor is good even during the heating operation in the extremely cold season, and the formation coefficient can be kept uniform.
[0023]
According to the second and third aspects of the present invention, in addition to the effect of the first aspect, by performing the additional expansion of the refrigerant liquid, the evaporation thereof can be further improved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of the present invention.
[Explanation of symbols]
1 Basic refrigeration circuit, 2 compressor, 3 4-way valve, 4 indoor heat exchanger, 7 outdoor heat exchanger, 9 refrigerant liquid tank, 10 bypass conduit, 11 pressure control valve, 12 solenoid valve, 13 capillary tube, 14 branch tube , 16 second bypass conduit.

Claims (3)

A compressor, a four-way valve, an indoor heat exchanger, a cooling expansion valve, a heating expansion valve, an outdoor heat exchanger, and the four-way valve are sequentially connected by conduits (8a), (8b), (8c), and (8d). In a basic refrigeration circuit in which a valve and a compressor are connected by a suction pipe, a bypass pipe is connected between the cooling expansion valve and the heating expansion valve installed in the pipe (8c) and the suction pipe, and installed in the bypass pipe. And a second bypass conduit between the conduit (8b) and the conduit (8d), and a pressure regulating valve and a solenoid valve respectively installed on the inlet side and the outlet side of the refrigerant liquid tank of the bypass conduit. A heat pump comprising a plurality of capillaries connected between the second bypass conduit and a branch pipe branched from the outlet side of the pressure regulating valve of the bypass conduit, the capillary tubes being built in the refrigerant liquid tank; apparatus. The heat pump device according to claim 1, wherein an expansion valve is provided in the branch pipe. The heat pump device according to claim 1, wherein the outlet side of the refrigerant liquid tank of the bypass conduit is a capillary tube.

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