JP2001227822A - Refrigerating air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating air conditioner of which refrigerant is combustible but has a small risk of depletion of the ozone layer as such refrigerant as R32, R290 or the like which has filled a refrigerant with small GWP, and at the same time has secured safety by reducing the amount of the filled refrigerant. SOLUTION: A combustible refrigerant is used, and at the same time the opening of a refrigerant flow rate-controlling device or the capacity of a compressor is controlled so that the degree of supercooling of the refrigerant at the outlet of a condenser can be set to an optimum value (5-20 deg.C for R32, and 5-17 deg.C for R290). Also, for example, a container for storing the refrigerant in a refrigerant circuit is abolished, the number of paths at the outlet side of the condenser is reduced, or the diameter of a heat transfer pipe at the outlet side of the condenser is reduced, thus reducing the capacity of a part where a liquid refrigerant stays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating and air-conditioning apparatus such as an air conditioner, a refrigerator and a freezer using a refrigerant for suppressing global warming.

[0002]

2. Description of the Related Art Conventionally, refrigeration and air-conditioning systems such as air conditioners, refrigerators and freezers have mainly used hydrochlorofluorocarbon (HCFC) -based refrigerants as refrigerants. Replacement with a system refrigerant is being pursued. However, R410A, which is currently regarded as a representative refrigerant among the HFC-based alternative refrigerants, is feared to have an influence on global warming, which is another environmental problem. That is, R410A has a larger global warming potential (an index indicating the degree of influence on global warming, hereinafter referred to as GWP) than a conventional HCFC-based refrigerant, and is not necessarily suitable as an alternative refrigerant. Therefore, there is a demand for the development of a refrigeration and air-conditioning system using a refrigerant having a low risk of depletion of the ozone layer and a smaller GWP.

To cope with this, refrigeration and air conditioning systems such as refrigeration systems and air conditioners using HFC32 (hereinafter referred to as R32) or HC290 (hereinafter referred to as R290) having a small GWP as a refrigerant can be considered. However, these refrigerants are flammable. Further, a conventional refrigeration and air-conditioning apparatus using an HCFC-based refrigerant, particularly a refrigeration and air-conditioning apparatus using a refrigerant flow control device such as an electric expansion valve, has a high pressure side as shown in FIG. Receiver 101 for storing the liquid refrigerant in the compressor, accumulator 102 for storing the liquid refrigerant in the low-pressure side, and the suction muffler 103 of the compressor 1
And the like, there are various spaces for storing the liquid refrigerant. In FIG. 10, 2 is a four-way valve, 3 is an outdoor heat exchanger as a heat source side heat exchanger, 5
Denotes a refrigerant flow control device such as an expansion valve, and 6 denotes an indoor heat exchanger as a use side heat exchanger. In addition, the refrigerant flow control device 5 normally controls the refrigerant superheat degree at the outlet side of the heat exchanger acting as an evaporator to be constant, and reduces the refrigerant subcooling degree at the heat exchanger outlet acting as a condenser. As a result, no particular consideration has been given to controlling the amount of liquid refrigerant in the refrigerant circuit to reduce the amount of refrigerant charged. Therefore, in such a conventional refrigeration and air conditioning system, H
Instead of CFC-based refrigerant, GW such as R32 and R290
It has been considered that using a refrigerant having a small P but having flammability requires a large amount of refrigerant to be charged, and that safety is a problem.

[0004] For these reasons, refrigeration and air-conditioning systems currently under development are HFC125 and HFC143.
a, a non-flammable non-azeotropic mixed refrigerant such as HFC134a is mainly used. However, in such a refrigeration / air-conditioning apparatus, problems in terms of service, such as securing the composition of the refrigerant gas due to gas leakage, have not yet been sufficiently solved.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems existing in the prior art, and has as its object the object of the present invention, such as the use of refrigerants such as R32 and R290. In addition, the present invention provides a refrigeration and air-conditioning system that is filled with a refrigerant that is flammable but has a low risk of depletion of the ozone layer and that has a small GWP, and that has a reduced amount of filling to ensure safety. Is to do.

[0006]

In order to achieve the above object, a refrigeration / air-conditioning apparatus according to the present invention comprises a refrigeration circuit having a refrigerant circuit in which a compressor, a condenser, a refrigerant flow controller and an evaporator are connected by refrigerant piping. In the air conditioner, a combustible refrigerant is used as the refrigerant, and a direct detection unit for directly detecting the refrigerant subcooling degree at the condenser outlet, so that the refrigerant subcooling degree at the condenser outlet becomes substantially the set value. And a control device for controlling the opening of the refrigerant flow control device based on the detection value detected by the direct detection means. With this configuration, it is possible to eliminate the excessive accumulation of the liquid refrigerant which has a large influence on the determination of the refrigerant charging amount, to reduce the size of the refrigeration air conditioner by improving the COP, and to reduce the refrigerant charging amount. Also,
This makes it possible to safely use a combustible refrigerant having no risk of destruction of the ozone layer and global warming. Here, the refrigeration / air-conditioning device means a concept including all air conditioning devices such as a cooling device and a cooling / heating device, and all refrigeration devices such as a refrigerator and a process cooling device.

Further, instead of the direct detection means, an alternative detection means for detecting a refrigerant physical property value which changes according to the degree of subcooling of the refrigerant at the outlet of the condenser may be used. Further, instead of controlling the opening of the refrigerant flow control device based on the detection value detected by the detection means, the compressor capacity may be controlled based on the detection value detected by the detection means.

[0008] Further, between the outlet of the condenser and the refrigerant flow control device, or between the outlet of the evaporator and the suction side of the compressor, only through the refrigerant pipe without passing through a container for storing the refrigerant. If the connection is made, the space for storing the liquid refrigerant can be eliminated, and the amount of charged refrigerant can be further reduced.

The condenser is a heat exchanger in which a high-pressure refrigerant flows through a heat transfer tube, and the high-pressure refrigerant exchanges heat with a cooling source outside the heat transfer tube. The flow area is made smaller than the refrigerant flow area on the condenser inlet side. With this configuration, the volume of the space in which the liquid refrigerant is stored can be further reduced, the refrigerant circulation speed increases, and the efficiency improves. Therefore, the size of the refrigeration / air-conditioning device can be reduced by that much, and the amount of charged refrigerant can be further reduced. As a specific means, the inner diameter of the heat transfer tube on the outlet side of the condenser is made smaller than the inner diameter of the heat transfer tube on the inlet side of the condenser,
It is possible to consider a method in which the number of refrigerant flow paths on the condenser outlet side is smaller than the number of refrigerant flow paths on the condenser inlet side.

Further, in the present invention, as a measure to further reduce the space volume in which the liquid refrigerant is stored and to reduce the amount of liquid refrigerant charged, the inner diameter of the pipe connecting the outlet of the condenser and the refrigerant flow control device is determined by the transmission of the condenser. It may be configured smaller than the inner diameter of the heat tube.

The direct detection means may be configured to directly detect the degree of subcooling of the refrigerant from the difference between the refrigerant temperature at the intermediate portion of the condenser and the refrigerant temperature at the outlet of the condenser.
Further, the refrigerant physical property value detected by the alternative detecting means may be a superheat degree of the compressor suction gas, a superheat degree of the compressor discharge gas, and a dryness of the compressor suction gas.

Further, the refrigerant circuit includes R32 as a refrigerant.
, The approximate set value of the refrigerant supercooling degree is 5
~ 20 ° C. As a result, it is possible to prevent ozone layer destruction and influence on global warming due to refrigerant discharge. Further, since the degree of subcooling of the refrigerant at the outlet of the condenser is controlled to the optimum value, the COP can be improved and the amount of refrigerant charged can be reduced.

[0013] The refrigerant circuit may include R32 as a refrigerant.
When the superheat degree of the compressor discharge gas is a set value of 40 ° C. or less, the capacity of the compressor and the condensation are set such that the approximate set value of the refrigerant subcooling degree is in the range of 5 to 20 ° C. Vessel size, evaporator size and refrigerant charge are combined,
The controller may control the refrigerant flow control device such that the superheat degree of the compressor discharge gas becomes a set value of the superheat degree of the compressor discharge gas. In this case, the degree of supercooling of the refrigerant and the degree of superheating of the discharge gas can be simultaneously controlled, so that the COP can be further improved and the amount of refrigerant charged can be reduced.

Further, the refrigerant circuit includes R32 as a refrigerant.
And the capacity of the compressor and the condenser so that the approximate set value of the subcooling degree of the refrigerant is within the range of 5 to 20 ° C. when the dryness of the compressor suction gas is a set value of 1 or less. The size of
The size of the evaporator and the charge amount of the refrigerant may be combined, and the controller may control the refrigerant flow control device such that the dryness of the compressor suction gas is substantially equal to the dryness set value. In this case, the control of the supercooling degree of the refrigerant at the outlet of the condenser and the control of the superheat degree of the compressor discharge gas by the dryness control of the compressor suction gas are simultaneously performed, so that the COP is further improved and the refrigerant filling amount is reduced. be able to.

Further, R290 is used as a refrigerant in the refrigerant circuit.
And the approximate set value of the degree of subcooling of the refrigerant is set in a range of 5 to 17 ° C. As a result, it is possible to prevent ozone layer destruction and influence on global warming due to refrigerant discharge. Further, since the degree of subcooling of the refrigerant at the outlet of the condenser is controlled to the optimum value, the COP can be improved and the amount of refrigerant charged can be reduced.

Further, the refrigerant circuit includes R29 as a refrigerant.
0, the capacity of the compressor such that when the superheat degree of the compressor suction gas is a set value of 0 ° C. or more, the approximate set value of the refrigerant subcooling degree is in the range of 5 to 17 ° C. The size of the condenser, the size of the evaporator and the refrigerant charge are combined,
The controller may control the refrigerant flow control device such that the superheat degree of the compressor suction gas is substantially equal to the set value of the superheat degree of the compressor suction gas. In this case, since both the refrigerant supercooling degree control and the superheat degree control of the compressor suction gas can be performed, the operation efficiency can be further improved, and the refrigerant charging amount can be reduced accordingly. Further, even if the refrigerant is 290, the discharge gas temperature can be set high, and the temperature of the hot air during the heating operation can be maintained at a predetermined value.

Further, the refrigerant circuit is provided with R29 as a refrigerant.
0, and when the superheat degree of the compressor discharge gas is a set value of 15 to 40 ° C., the approximate set value of the refrigerant subcooling degree is 5 to 17
° C, the capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charge are combined so that the superheat degree of the gas discharged from the compressor is reduced by the controller. The refrigerant flow control device may be configured to control the superheat degree of the gas to a set value. in this case,
Since both the control of the degree of supercooling of the refrigerant and the degree of superheating of the compressor discharge gas can be performed, the operation efficiency can be further improved, and the amount of refrigerant charged can be reduced accordingly.

The degree of supercooling of the refrigerant, the degree of superheating of the compressor suction gas, and the degree of superheating of the compressor discharge gas are controlled within a range of about ± 1 ° C. or less with respect to the set values. By performing such control, the control accuracy is increased, the fluctuation of the required refrigerant amount during operation is reduced, and the refrigerant charge amount can be further reduced.

In the heat pump refrigeration / air-conditioning apparatus of the present invention, a high pressure port of a four-way valve is connected to the discharge side of the compressor, and a low pressure port of the four-way valve is connected to the suction side of the compressor. A heat source side heat exchanger, a refrigerant flow controller, and a use side heat exchanger are sequentially connected between the two switching ports of the valve,
The refrigerant flow control device is controlled so that the refrigerant subcooling degree at the outlet of the outdoor heat exchanger is substantially set to a set value when performing the cooling operation with the four-way valve as a cooling cycle. When the heating operation is performed as a heating cycle, the supercooling degree of the refrigerant at the outlet of the indoor heat exchanger is controlled to a substantially set value. With this configuration, in either the cooling or heating operation, the refrigerant subcooling degree at the condenser outlet is controlled to an appropriate value,
Since the COP is improved, the refrigerant charge is reduced. Here, the heat pump type refrigeration / air-conditioning device refers to a heat pump type refrigeration / air-conditioning device in which a refrigerant circuit is reversibly switchable and capable of performing a cooling (including cooling) operation and a heating (including heating) operation. .

In the heat pump refrigeration / air-conditioning apparatus according to the present invention, an auxiliary pressure reducer may be provided in any one of the front and rear portions of the refrigerant flow control device, or before and after the refrigerant flow control device. According to this configuration, even in the case where a failure occurs in which the refrigerant flow control device becomes inoperative and remains fully open, an extreme liquid return operation can be prevented.

In the heat pump refrigeration / air-conditioning apparatus of the present invention, the high pressure port of the four-way valve is connected to the discharge side of the compressor, and the low pressure port of the four-way valve is connected to the suction side of the compressor. A heat source side heat exchanger between the two switching ports of the valve, a first for preventing a refrigerant flow from the heat source side heat exchanger;
A first refrigerant flow control device connected in parallel with a check valve, a second refrigerant flow control device connected in parallel with a second check valve allowing a flow of refrigerant from the first refrigerant flow control device, and a use side heat exchanger The first refrigerant flow control device is controlled so that the refrigerant supercooling degree at the heat source side heat exchanger outlet is set to a substantially set value when performing the cooling operation with the four-way valve as a cooling cycle, The two-refrigerant flow control device is controlled so that the degree of subcooling of the refrigerant at the outlet of the use-side heat exchanger is substantially set when the four-way valve is heated as a heating cycle. With this configuration, the liquid pipe between the heat source-side heat exchanger and the use-side heat exchanger becomes a gas-liquid two-layer flow pipe, and the amount of refrigerant charged is reduced.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment in which the present invention is embodied in a heat pump type air conditioner as a refrigerating air conditioner will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of the heat pump air conditioner according to Embodiment 1. In this figure, the discharge side of the variable displacement compressor 1 controlled by the rotation speed is connected to the high pressure port 2a of the four-way valve 2, and the suction side of the variable displacement compressor 1 is connected to the low pressure port 2b of the four-way valve 2. Further, a plate-fin type outdoor heat exchanger 3 serving as a heat source side heat exchanger for exchanging heat with outside air between the switching ports 2c and 2d of the four-way valve 2; A refrigerant flow controller (specifically, an electric expansion valve in this case) 5 as a mechanism, and a plate fin type indoor heat exchanger 6 that exchanges heat with indoor air as a use side heat exchanger are sequentially connected. 4 is a blower for the outdoor heat exchanger 3 and 7 is a blower for the indoor heat exchanger 6.

As is apparent from FIG. 1, the refrigerant circuit can be switched between cooling and heating by switching the four-way valve 2. That is, during the cooling operation, the refrigerant circulates as indicated by a solid arrow in the drawing, and during the heating operation, the refrigerant circulates as indicated by a dotted arrow in the drawing. Outdoor heat exchanger 3 during cooling operation
, The indoor heat exchanger 6 acts as an evaporator, and during the heating operation, the indoor heat exchanger 6 acts as a condenser, and the outdoor heat exchanger 3 acts as an evaporator. Further, the refrigerant circuit is provided between the heat exchangers 3 and 6 and the refrigerant flow control device 5, and
No container (liquid reservoir) for storing the liquid refrigerant is provided between the heat exchangers 3 and 6 and the suction side of the compressor 1.

The refrigerant sealed in the refrigerant circuit is a low GWP refrigerant, for example, R32 of a hydrofluorocarbon (HFC) -based refrigerant and R290 of a hydrocarbon (HC) -based refrigerant. The refrigerating machine oil for lubricating the moving part is of an alkylbenzene type.

In the above configuration, the outdoor heat exchanger 3
And the indoor side heat exchanger 6 is a plate fin type heat exchanger, and when acting as a condenser,
The high-pressure refrigerant flows through the inside of the heat transfer tube, and the high-pressure refrigerant and a cooling source outside the heat transfer tube exchange heat with each other. Further, the outdoor heat exchanger 3 is configured such that the refrigerant flow path cross-sectional area of the outlet side part 3b when acting as a condenser is compared with the refrigerant flow path cross-sectional area of the inlet side part (portion on the four-way valve 2 side) 3a. And smaller. Similarly, the indoor-side heat exchanger 6 changes the cross-sectional area of the refrigerant flow path of the outlet side part 6b when acting as a condenser to the refrigerant flow path cross-sectional area of the inlet side part (portion on the four-way valve 2 side) 6a. It is smaller than that.

That is, in the cooling cycle in which the outdoor heat exchanger 3 acts as a condenser, the number of passes on the inlet side 3a is four, whereas the number of passes on the outlet side 3b is two. In addition, while the number of passes on the inlet side 6a in the heating cycle in which the indoor heat exchanger 6 acts as a condenser is two, the number of passes on the outlet side 6b is one.

Further, in the cooling cycle in which the outdoor heat exchanger 3 acts as a condenser, the diameter of the heat transfer tube at the outlet side 3b is made smaller than the diameter of the heat transfer tube at the inlet side 3a. In the heating cycle in which the heat exchanger 6 acts as a condenser, the diameter of the heat transfer tube on the outlet side 6b is smaller than the diameter of the heat transfer tube on the inlet side 6a in the heating cycle.
For example, while the outer diameter of the heat transfer tube at the inlet side 3a of the outdoor heat exchanger 3 is 7 mm and the wall thickness is 0.25 mm, the outer diameter of the heat transfer tube at the outlet side 3b is 5 m.
m, and the thickness is 0.23 mm. Similarly, the outer diameter of the heat transfer tube at the inlet side portion 6a of the indoor heat exchanger 6 is set to 7
mm and a wall thickness of 0.25 mm, the outer diameter of the heat transfer tube at the outlet side portion 6b is 5 mm, and the wall thickness is 0.23 mm.
mm.

A pipe connecting the outdoor heat exchanger 3 and the indoor heat exchanger 6 is provided with a pipe diameter of a heat transfer tube at the outlet side portion 3b of the outdoor heat exchanger 3, and a pipe for indoor heat exchange. The diameter of the heat transfer tube at the outlet side portion 6b of the vessel 6 is smaller than the diameter of the tube. For example, the heat transfer tube at the outlet side portion 3b of the outdoor heat exchanger and the heat transfer tube at the outlet side portion 6b of the indoor heat exchanger 6 have a tube outer diameter of 5 mm and a wall thickness of 0.23 mm, respectively. The pipe connecting the outdoor heat exchanger 3 and the indoor heat exchanger 6 has a pipe outer diameter of 4 mm and a wall thickness of 0.21 mm.

In the variable displacement compressor 1, the outside air temperature Tao detected by the outside air temperature detector 12 and the indoor air temperature Tai detected by the indoor air temperature detector 13 are transmitted to the control device 21. The compression capacity is variably controlled by changing the rotation speed according to the cooling or heating load calculated in 21.

Further, the opening of the refrigerant flow control device is controlled such that the refrigerant supercooling degree Tqs at the condenser outlet becomes a predetermined value. That is, during the cooling operation, the refrigerant condensation temperature Tc detected by the intermediate temperature detector 8 in the middle of the outdoor heat exchanger 3 and the liquid refrigerant detected by the outlet temperature detector 9 at the outlet of the outdoor heat exchanger 3. The temperature Tq is transmitted to the control device 21, and the control device 21 calculates the refrigerant supercooling degree Tqs of the high-pressure liquid refrigerant at the outlet of the outdoor heat exchanger 3, so that the refrigerant supercooling degree Tqs becomes an optimum value. The opening of the refrigerant flow control device 5 is controlled. During the heating operation, the refrigerant condensation temperature Tc detected by the intermediate temperature detector 10 in the middle of the indoor heat exchanger 6 and the liquid refrigerant detected by the outlet temperature detector 11 at the outlet of the indoor heat exchanger 6 The temperature Tq is transmitted to the control device 21, and the control device 21 transmits the refrigerant supercooling degree T at the outlet of the outdoor heat exchanger 3.
qs is calculated, and the opening degree of the refrigerant flow control device 5 is controlled such that the refrigerant subcooling degree Tqs becomes an optimum value.

The optimum value of the refrigerant subcooling degree Tqs is a value at which the energy efficiency (an index indicating the ratio of the capacity to the power consumption, that is, Coefficient of Performance, hereinafter abbreviated as COP) indicates a high level. Say. Further, when the refrigerant flow rate is controlled so that the refrigerant subcooling degree Tqs becomes the above-described optimum value, the refrigerant subcooling degree at the condenser outlet side is not excessively increased, and the effect of reducing the refrigerant charging amount is obtained. In addition, the COP increases, the size of the refrigeration and air conditioning system can be reduced, and the amount of refrigerant charged can be reduced accordingly.

FIG. 2 is data showing the optimum value of the refrigerant subcooling degree Tqs for R22, R32 and R290. This data shows that the rated cooling capacity under the JIS standard air condition is 2. for a heat pump type air-air conditioner using R22, R32 and R290 as refrigerant.
The results are obtained by using each room air conditioner of 8 kw and operating this room air conditioner under JIS heating standard air conditions. In FIG. 2, the horizontal axis represents the degree of refrigerant subcooling Tqs at the condenser outlet, and the vertical axis represents COP.

The following can be said from this data. R3
2. The maximum COP of R290 is the maximum C of the conventional refrigerant R22.
Refrigerant subcooling degree Tq larger than OP and showing maximum COP
As for s, R32 and R290 are larger than R22. Furthermore, in the refrigerant supercooling degree region larger than the refrigerant supercooling degree at which the COP is the maximum, the decrease rate of the refrigerant supercooling degree Tqs is:
R32 and R290 are smaller than R22. As a result, the optimum value of the refrigerant subcooling degree Tqs at the condenser outlet is approximately 5 to 20 ° C. for R32, and approximately 5 to 20 ° C. for R290.
It can be said that the temperature is 17 ° C.

The reason for the above result is as follows.
It is considered as follows. In general, the refrigeration cycle CO
P is theoretically the refrigerant subcooling degree Tqs in the region of the refrigerant subcooling degree Tqs equal to or less than a certain value, as viewed from the Mollier diagram.
The higher the is, the higher it is. However, the refrigerant-side heat transfer coefficient on the inner surface of the heat transfer tube in the supercooled liquid portion is smaller than that in the gas-liquid two-phase flow portion. From this, it is considered that when the degree of subcooling of the refrigerant is too large, the COP is rather deteriorated. Therefore, it is considered that the COP of the refrigerating air conditioner can be maintained at a high value near the maximum value by maintaining the refrigerant subcooling degree at an optimum value within a certain range. Although the absolute value of the heat transfer coefficient on the refrigerant side also differs depending on the flow rate of the refrigerant, in this test, the supercooled liquid portion is 1000 to 2
2,000 W / m ² · K, whereas the two-phase flow
000 W / m ² · K or more.

Further, as a characteristic of the thermal properties of the R32 refrigerant, the liquid refrigerant has a higher thermal conductivity than the R22 refrigerant. That is, when the condensing temperature is 44 ° C., the thermal conductivity of the liquid refrigerant is R22 is 0.09126 W / m · K, while R32 is 0.1482 W / m · K, which is approximately the same as R22. 1.6 times or more. Therefore, the refrigerant side heat transfer coefficient of the supercooled liquid portion of R32 is larger than that of R22, and C
The optimum value of the refrigerant supercooling degree Tqs at which OP becomes the maximum value is R2
It is thought to be larger than two cases.

In the case of R290,
As a characteristic of the thermophysical properties of the refrigerant, the specific heat of the liquid refrigerant is higher than R22. For example, when the condensation temperature is 45 ° C., R22
Is 1.193 kJ / kg · K, whereas R29
0 is 2.573 kJ / kg · K, which is about 2.2 times or more. Therefore, as the refrigerant subcooling degree Tqs increases, the degree of increase in the efficiency of the refrigeration cycle of R290 becomes higher than in the case of R22, and the refrigerant subcooling degree Tq of R290
It is considered that the optimum value of s was larger than that of R22.

The above is the calculation of the optimum value of the refrigerant subcooling degree Tqs under the JIS heating air condition. The optimal refrigerant subcooling degree of the heat pump type air conditioner does not differ greatly between the cooling operation and the heating operation, and the heating operation is longer than the cooling operation when viewed in the annual operation time. From COP during heating operation to C during cooling operation
It has priority over OP. Therefore, it is preferable to set the optimum refrigerant subcooling degree based on the heating operation. Also, by setting the optimal refrigerant subcooling degree in this way,
The high COP during the heating operation is improved, and the amount of refrigerant charged can be reduced.

In the above-described refrigerant supercooling degree control, the deviation of the actual refrigerant subcooling degree from the set value of the refrigerant subcooling degree when controlling the refrigerant subcooling degree Tqs is ± 1 ° C.
, The opening degree of the refrigerant flow control device is controlled. Such a deviation value as a criterion for determining whether to control the opening degree, such as ± 1 ° C., is hereinafter referred to as a threshold value.

Such a threshold is generally set when controlling the degree Tqs of supercooling of the refrigerant in the refrigerating air conditioner. For example, in a conventional refrigeration air conditioner filled with R22, when the set value of the refrigerant subcooling degree Tqs is controlled at 10 ° C., the threshold value is set to ± 2 in consideration of measurement errors of various sensors.
° C, and as a result, control has been performed in a range of 8 to 12 ° C with respect to the set value of 10 ° C. However, R32, R29
In the case of the refrigeration and air-conditioning apparatus charged as refrigerant 0, the refrigerant density of the liquid refrigerant is smaller than that of R22. Therefore, when the threshold value is set to ± 2 ° C. similarly to the case of R22 refrigerant, the fluctuation of the refrigerant circulation amount becomes large. The problem arises.

That is, when the amount of circulating refrigerant decreases, the degree of superheating of the compressor suction gas becomes extremely large, and the discharge gas temperature Td of the compressor rises. Reliability problems can occur. Further, when the refrigerant circulation amount is increased, the dryness of the compressor suction gas is extremely reduced to perform the liquid compression operation, and the discharge gas temperature is lowered, which may cause a problem in the efficiency and reliability of the device. For example, when the condensing temperature is 44 ° C., the density of the liquid refrigerant is 1110 kg / m ³ for R22, 870 kg / m ³ for R32 and 4 kg for R290.
61 kg / m ³ , 7 times that of R22
8% and 41%. Therefore, the refrigerant subcooling degree Tqs
Is 1 ° C., the fluctuation of the refrigerant circulation amount is 1.28 times for R32 and 2.4 times for R290 with respect to R22.
For this reason, the threshold value of the refrigerant subcooling degree Tqs is smaller in the case of R32 and R290 than in the case of R22, and ± 1.
C. or lower is preferred. In addition, since the refrigeration / air-conditioning operation can be operated closer to the target value by reducing the control width in this manner, the refrigeration / air-conditioning system can be operated at a high C.
The operation can be performed in the OP, and the refrigerant charging amount can be reduced.

Next, the operation of the first embodiment will be described. When performing the cooling operation of the heat pump type air conditioner of the first embodiment, the operation is performed with the four-way valve 2 at the position of the cooling cycle (the connection state of the solid line in the drawing). As a result, the high-pressure gas refrigerant discharged from the compressor 1 circulates as indicated by the solid arrow in the figure, and exchanges heat with outdoor air in the outdoor heat exchanger 3 to be condensed. At this time, the refrigerant condensation temperature T detected by the intermediate temperature detector 8 and the outlet temperature detector 9 of the outdoor heat exchanger 3
c, The liquid refrigerant temperature Tq is transmitted to the control device 21. In the control device 21, these refrigerant temperatures Tc,
The refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3 is calculated from Tq. The opening of the refrigerant flow control device 5 is controlled by the control device 21 so that the refrigerant subcooling degree Tqs becomes ± 1 ° C. with respect to a set value set in a high COP range. As a result, the refrigerant subcooling degree T at the outlet of the outdoor heat exchanger 3
qs is kept at the optimal value. In addition, the outdoor heat exchanger 3
The supercooled liquid refrigerant at the outlet is decompressed by the refrigerant flow control device 5, exchanges heat with the indoor air in the indoor heat exchanger 6, cools the indoor air, and evaporates and evaporates the refrigerant itself, via the four-way valve 2. It returns to the compressor 1.

Next, during the heating operation, the operation is performed with the four-way valve 2 at the position of the heating cycle (the connection state indicated by the dotted line in the figure).
Thereby, the high-pressure gas refrigerant discharged from the compressor 1 circulates as indicated by a dotted arrow in the figure, exchanges heat with the indoor air in the indoor heat exchanger 6, heats the indoor air, and the refrigerant itself is cooled. It is condensed and liquefied. At this time, the refrigerant condensation temperature Tc and the liquid refrigerant temperature Tq detected by the intermediate temperature detector 10 and the outlet temperature detector 11 of the indoor heat exchanger 6 are transmitted to the control device 21. Further, the controller 21 calculates the refrigerant subcooling degree Tqs at the outlet of the indoor heat exchanger 6 from the refrigerant temperatures Tc and Tq. And the refrigerant flow control device 5
Is controlled by the control device 21 so that the refrigerant subcooling degree Tqs becomes ± 1 ° C. with respect to a set value set in a high COP range. As a result, the refrigerant subcooling degree Tqs at the outlet of the indoor heat exchanger 6 is maintained at the optimum value. The supercooled liquid refrigerant thus controlled is depressurized by the refrigerant flow control device 5 and exchanges heat with outdoor air in the outdoor heat exchanger 3, and the refrigerant is heated by the outdoor air and vaporized, and the four-way valve 2 is opened. It returns to the compressor 1 via the compressor.

During the cooling / heating operation, the outside air temperature detector 12 outputs the outdoor air temperature Tao, and the indoor air temperature detector 13 outputs the indoor air temperature Tai.
1 and the air-conditioning load is calculated from these air temperatures Tao and Tai. Further, the rotation speed of the compressor 1 is controlled based on the cooling / heating load, and the compression capacity is controlled.

Next, effects of the first embodiment will be described. Since the refrigerant flow rate is controlled by the refrigerant supercooling degree Tqs at the outlet of the outdoor heat exchanger 3 or the indoor heat exchanger 6 acting as a condenser, unnecessary liquid in the refrigerant circuit having a large influence on the refrigerant filling amount. The accumulation of the refrigerant can be eliminated, and as a result, the amount of the charged refrigerant can be reduced.

Further, the degree of subcooling of the refrigerant Tqs is determined by using the intermediate temperature detectors 8, 1 of the heat exchangers 3, 6 acting as condensers.
0 and the outlet temperature detectors 9 and 1
Since it is calculated from the outlet liquid refrigerant temperature Tq detected in step 1, the refrigerant supercooling degree Tqs can be accurately measured.

Also, since the refrigerant subcooling degree Tqs is controlled to an optimum value at which the COP is close to the maximum value, the ratio of the liquid refrigerant amount in the refrigerant circuit, which has a great influence on the refrigerant charge, is minimized. At the same time, the amount of refrigerant charged by reducing the COP of the refrigeration air conditioner to the maximum value is simultaneously achieved. Therefore, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved.

When R32 is used, the optimum value of the degree of subcooling of the refrigerant Tqs is set to 5 to 20 ° C.
When 0 is used, the optimum value of the refrigerant supercooling degree Tqs is 5
By setting the temperature to １７17 ° C., the refrigerant charging amount in the refrigeration and air-conditioning system using R32 and R290 can be reduced to a necessary minimum amount, and the performance can be maximized.

Further, since the threshold value for controlling the degree of subcooling of the refrigerant Tqs is set to 1 ° C., it is possible to reduce the fluctuation of the required refrigerant amount due to the fluctuation of the operating condition while maintaining the practicality. It is possible to prevent the liquid compression and the abnormal increase in the superheat degree of the compressor suction gas due to the fluctuation amount, and to reduce the refrigerant charging amount.

Further, a pipe connecting the outlet of the heat exchanger serving as a condenser and the refrigerant flow control device (that is, between the outdoor heat exchanger 3 and the refrigerant flow control device 5, and the indoor heat exchanger 6) And a pipe between the refrigerant flow control device 5) and
A pipe connecting the heat exchanger serving as an evaporator and the suction side of the compressor 1 (that is, a pipe between the outdoor heat exchanger 3 and the compressor 1, and a pipe connecting the indoor heat exchanger 6 and the compressor 1) Each pipe is connected only with piping equipment such as pipes, joints, valves, etc., without providing a container (liquid reservoir) for storing liquid refrigerant. Thus, the amount of refrigerant charged into the refrigerant circuit can be reduced.

The number of passes and the inner diameter of the heat transfer tube are determined by changing the outlet side of the condenser (that is, the outlet side 3b during cooling of the outdoor heat exchanger 3 and the outlet side during heating operation of the indoor heat exchanger 6). The refrigerant passage area of the portion 6b) is determined by the inlet side portion of the condenser (that is, the inlet side portion 3a during the cooling of the outdoor heat exchanger 3 and the inlet side portion 6a during the heating operation of the indoor heat exchanger 6). Since it is smaller than the refrigerant passage area, the passage volume of the portion through which the liquid refrigerant passes is reduced, and the amount of charged refrigerant can be reduced. The flow velocity becomes faster, the heat transfer coefficient on the refrigerant side in this part is improved, and the improvement in the capacity can further reduce the refrigerant charge. In this case, although the pressure loss in the refrigerant pipe increases, the absolute value of the pressure loss is small due to the supercooled liquid portion, and the CO
There is almost no effect on P.

A pipe connecting the outdoor heat exchanger 3 and the indoor heat exchanger 6 is provided with a pipe diameter of a heat transfer tube at the outlet side portion 3b of the outdoor heat exchanger 3 and an indoor heat exchange. Since the diameter of the heat transfer tube at the outlet side portion 6b of the vessel 6 is smaller than the diameter of the heat transfer tube, the passage volume of the portion through which the liquid refrigerant passes is reduced, and the amount of charged refrigerant can be further reduced.

In this embodiment, R3 is used as the refrigerant.
2 or R290 is used. This refrigerant has a lower refrigerant liquid density than the conventional refrigerant R22, and reduces the amount of refrigerant charged in the apparatus, thereby reducing the cost and time required for refrigerant recovery performed when the apparatus is disposed of. Thus, a refrigerating and air-conditioning apparatus having excellent recyclability can be obtained.

Embodiment 2 Next, a second embodiment will be described with reference to FIG. Note that the same or corresponding portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be simplified. In the second embodiment, the heat pump air conditioner of the first embodiment is changed to an air conditioner dedicated to cooling operation. Therefore, the second embodiment is different from the first embodiment in that a portion related to the heating operation in the first embodiment is removed,
The other points are basically the same as the first embodiment.

That is, in the refrigerant circuit, during the cooling operation, the refrigerant discharged from the compressor 1 circulates as shown by the solid arrow in the figure, condenses and liquefies in the outdoor heat exchanger 3, and is depressurized by the refrigerant flow controller 5. The indoor air is cooled by the indoor heat exchanger 6, evaporated and vaporized, and returned to the compressor 1. In the refrigerant circuit configured as described above, although not shown, the outdoor heat exchanger 3 has the same number of passes and the diameter of the heat transfer tube as in the first embodiment. Further, the method of measuring the refrigerant subcooling degree Tqs, the set value, and the threshold value are the same as those in the first embodiment. Further, the piping connecting the outdoor heat exchanger 3 and the refrigerant flow control device 5 has the same relationship as in the first embodiment. Also,
The capacity control of the compressor 1 is also in accordance with the first embodiment.

Therefore, also in the second embodiment, the operation is controlled in the same manner as in the cooling operation in the first embodiment, so that the refrigerant charge is reduced and the COP is improved as in the first embodiment. be able to.

Embodiment 3 Next, a third embodiment will be described with reference to FIG. The same or corresponding portions as those in the first and second embodiments are denoted by the same reference numerals, and description thereof will be simplified.

In the third embodiment, the superheat degree Tds of the compressor discharge gas is detected by the substitute detecting means as the refrigerant physical property value which changes in correlation with the refrigerant subcool degree Tqs in the second embodiment. The controller controls the superheat degree Tds of the compressor discharge gas to a set value so that the refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3 becomes the optimum value described in the first embodiment. 5 is controlled.

The alternative detecting means includes a condenser temperature Tc detected by the intermediate temperature detector 8 of the outdoor heat exchanger 3 acting as a condenser, and a refrigerant temperature detection at the entrance of the outdoor heat exchanger 3 acting as a condenser. And the compressor discharge gas temperature Td detected by the compressor 14. Note that the refrigerant temperature detector 14 in FIG. 4 may be provided on the discharge pipe of the compressor 1. Then, the control device 23 calculates the superheat degree Tds of the compressor discharge gas from the detected temperatures Tc and Td. Further, the refrigerant circuit according to the third embodiment includes:
When the refrigerant of R32 is charged in consideration of the case where the outside air temperature becomes high, the set value of the superheat degree Tds of the discharge gas is set to 4
0 ° C. or less, the threshold is ± 1 ° C., and the degree of superheat T
When ds reaches this set value, the refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3 acting as a condenser
, The rated capacity of the compressor 1, the size of the outdoor heat exchanger 3, the size of the indoor heat exchanger 6, and the refrigerant charge amount so that the optimum value is within the range of 5 to 20 ° C. Combined. When the refrigerant circuit is filled with R290 refrigerant, the set value of the superheat degree Tds of the discharged gas is set to 1
5 to 40 ° C., threshold value ± 1 ° C., superheat degree Td of discharge gas
When s reaches this set value, the compression is performed so that the refrigerant supercooling degree Tqs at the outlet of the outdoor heat exchanger 3 acting as a condenser is within the aforementioned optimum value, that is, within the range of 5 to 17 ° C. Rated capacity of the unit 1, the size of the outdoor heat exchanger 3,
The size of the indoor heat exchanger 6 and the amount of refrigerant charged are combined.

Therefore, in the third embodiment, the COP is improved by controlling the refrigerant supercooling degree Tqs to an optimum value and controlling the superheat degree Tds of the discharge gas to a set value. The ratio of the amount of liquid refrigerant in the refrigerant circuit having a large effect on the amount of refrigerant charged is minimized, and the amount of refrigerant charged is reduced by maximizing the COP of the refrigeration and air conditioning system. Therefore, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved. Also, the superheat degree Td of the compressor discharge gas
By limiting s to a temperature within an allowable range, electrical equipment such as a compressor motor is prevented from being overheated and damaged. Further, the threshold value for controlling the superheat degree Tds of the compressor discharge gas is ± 1.
° C, it is possible to reduce the fluctuation amount of the required refrigerant amount due to the fluctuation of the operating condition, and to prevent the abnormal increase of the superheat degree of the liquid compression and the compressor suction gas accompanying the refrigerant fluctuation amount,
Refrigerant charge can be reduced.

Embodiment 4 Next, a fourth embodiment will be described with reference to FIG. Note that the same or corresponding portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be simplified.

The fourth embodiment is different from the first embodiment in that the control of the refrigerant flow control device 5 during the heating operation is changed. The other points are the same as the first embodiment. That is, during the heating operation, the superheat degree Tss of the compressor intake gas is detected by the substitute detection means as a refrigerant physical property value that changes in correlation with the refrigerant subcool degree Tqs, and the superheat degree of the compressor intake gas is detected by the control device 24. Tss is controlled to a set value, and the opening degree of the refrigerant flow control device 5 is controlled so that the refrigerant subcooling degree Tqs at the outlet of the indoor heat exchanger 6 becomes the optimum value described in the first embodiment. It was made.

This alternative detecting means includes an intermediate temperature detector 8 for detecting the refrigerant evaporation temperature Te of the outdoor heat exchanger 3 acting as an evaporator during the heating operation, and an outdoor heat exchanger acting as an evaporator during the heating operation. And a suction gas temperature detector 15 for detecting a compressor suction gas temperature Ts at the outlet of the compressor 3. The intake gas temperature detector 15 in FIG. 5 may be provided on the intake pipe of the compressor 1 as a matter of course.
Further, control device 24 differs in control during the heating operation as compared with control device 21 in the first embodiment,
The superheat degree Tss of the compressor suction gas is calculated from the detected temperatures Te and Ts. In the refrigerant circuit according to the fourth embodiment, the refrigerant of R290 is charged, the superheat degree Tss of the compressor suction gas is set to an appropriate value of 0 ° C. or more, and the threshold value is set to ± 1. ° C, and during the heating operation, when the superheat degree Tss of the compressor suction gas reaches this set value, the refrigerant supercooling degree Tqs at the outlet of the indoor heat exchanger 6 acting as a condenser is the optimal value, That is, the rated capacity of the compressor 1, the size of the outdoor heat exchanger 3, the size of the indoor heat exchanger 6, and the refrigerant charging amount are combined so as to be within the range of 5 to 17 ° C.

Generally, when R290 is used as the refrigerant, the discharge pressure and the discharge gas temperature of the refrigeration cycle are lower than those of the conventional R22 refrigerant due to the thermophysical characteristics of R290. For example, a refrigerant condensation temperature of 45 ° C, a refrigerant evaporation temperature of 5 ° C,
Assuming that the degree of superheating of the compressor suction gas is 10 ° C. and the degree of supercooling of the refrigerant at the condenser outlet Tqs is 5 ° C., the condensing pressure, the discharge gas temperature Td and the superheat degree Tds of the discharge gas at that time are respectively:
When conventional R22 is used as a refrigerant, it is 1.73.
MPa, 72 ° C and 27 ° C, whereas R29
1.53 MPa, 5 when 0 is used as the refrigerant
8 ° C and 13 ° C, discharge pressure is about 0.9 times, discharge gas temperature Td drops by 14 ° C, superheat degree of discharge gas is 14 ° C
descend. Such a decrease in the discharge gas temperature Td is good for securing the reliability of the device such as protection of the compressor motor in an actual refrigeration and air-conditioning system, but the decrease in the temperature of the blown hot air due to the decrease in the blown air temperature in the heating operation. I am concerned.

In the fourth embodiment, during the heating operation, as described above, the superheat degree Tss of the compressor suction gas is controlled to 0 ° C. or higher, so that the compressor discharge gas temperature Td is appropriately maintained, and the refrigerant superheat is maintained. Since the cooling degree Tqs is controlled to the optimum value, the COP is improved, the refrigeration / air-conditioning apparatus can be reduced in size, the refrigerant charge amount can be reduced, and the temperature of the hot air during the heating operation can be prevented from lowering. Can be.
Further, since the threshold value for controlling the superheat degree Tss of the compressor suction gas is set to ± 1 ° C., the amount of change in the required amount of refrigerant due to the change in operating conditions can be reduced, and the liquid compression accompanying the amount of refrigerant change In addition, it is possible to prevent an abnormal increase in the degree of superheat of the compressor suction gas and reduce the amount of refrigerant charged.

Embodiment 5 Next, a fifth embodiment will be described with reference to FIG. The same or corresponding parts as in the second embodiment are denoted by the same reference numerals, and the description is simplified. In the fifth embodiment, the control of the refrigerant flow control device 5 is changed in the second embodiment, and the other points are the same as the second embodiment. That is, the dryness i of the compressor intake gas is detected by the substitute detection means as a refrigerant physical property value that changes in correlation with the refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3, and the controller 25 detects the compressor intake gas Is controlled to a set value, and the opening degree of the refrigerant flow control device 5 is adjusted so that the refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3 becomes the optimum value described in the first embodiment. It is intended to be controlled.

This alternative detecting means is constituted by a dryness detector 16 of the compressor suction gas provided on the suction side of the compressor 1. The control of the refrigerant flow control device 5 of the control device 25 is different from that of the control device 21 of the second embodiment. Further, the refrigerant circuit in the fifth embodiment is filled with the refrigerant of R32, and the set value of the dryness i is set to an appropriate value of 0.95 to 1, and during the cooling operation, the dryness of the compressor intake gas is reduced. When the degree i reaches this set value, the refrigerant subcooling degree Tqs at the outlet of the outdoor heat exchanger 3 acting as a condenser becomes the optimum value, that is, 5
定 格 17 ° C., the rated capacity of the compressor 1,
The size of the outdoor heat exchanger 3, the size of the indoor heat exchanger 6, and the amount of refrigerant charged are combined.

Generally, when R32 is used as a refrigerant,
Due to the thermophysical characteristics of R32, the discharge pressure and the discharge gas temperature Td of the refrigeration cycle are higher than those of the conventional R22 refrigerant. For example, a refrigerant condensation temperature of 45 ° C, a refrigerant evaporation temperature of 5 ° C,
Superheat degree of compressor suction gas 10 ° C, refrigerant subcooling degree Tqs5
° C, the condensation pressure, the discharge gas temperature Td and the superheat degree Tds of the discharge gas are 1.73 MPa, 72 ° C and 27 ° C, respectively, when the conventional R22 is used.
In contrast, when R32 is used, 2.7 is used.
The discharge pressure is about 1.6 times, the discharge gas temperature Td is 14 ° C., and the discharge gas superheat increases by 14 ° C. Further, in an actual refrigeration air conditioner, it is assumed that the operation is performed under a condition in which the condensing temperature is higher, and the discharge pressure, the discharge gas temperature Td, or the superheat degree Tds of the discharge gas are considered.
Is expected to rise further. As described above, when the discharge gas temperature Td increases, the deterioration of the refrigerating machine oil, the deterioration of the windings of the compressor motor, and the deterioration of various structural components tend to progress. Care must be taken to ensure reliability.

However, in the fifth embodiment, as described above, the dryness i of the compressor intake gas is set to 0.95 to 1
By controlling the compressor suction gas to be wet, the superheat degree Tds of the compressor discharge gas can be appropriately maintained. Therefore, in the fifth embodiment, during the cooling operation, the refrigerant supercooling degree Tqs is controlled to the optimum value, and the COP is improved by controlling the superheat degree Tds of the compressor discharge gas to the set value. Accordingly, the size of the refrigeration air conditioner can be reduced, and the amount of refrigerant charged can be reduced. Furthermore, since the degree of superheat Tds of the discharge gas is controlled to be low, overheating damage to the electric equipment is prevented.

Embodiment 6 FIG. Next, a sixth embodiment will be described with reference to FIG. The same or corresponding parts as in the second embodiment are denoted by the same reference numerals, and the description is simplified. The sixth embodiment differs from the second embodiment in that the control of the refrigerant subcooling degree Tqs is changed. The other points are the same as the second embodiment. That is, the control device 2
Reference numeral 6 denotes a refrigerant excess from the condensing temperature Tc detected by the intermediate temperature detector 8 of the outdoor heat exchanger 3 and the liquid refrigerant temperature Tq detected by the outlet temperature detector 9 at the outlet of the outdoor heat exchanger 3. Although the operation of the cooling degree Tqs is the same, the variable capacity compressor 1
Is controlled so that the refrigerant supercooling degree Tqs at the outlet of the outdoor heat exchanger 3 becomes the optimum value described in the first embodiment. In this case, as the refrigerant flow control device 51, a device whose opening degree is fixed or variable depending on the cooling load is used.

With this configuration, the same effect as in the first embodiment can be obtained. Therefore, unnecessary accumulation of the liquid refrigerant in the refrigerant circuit having a great influence on the refrigerant charge can be eliminated, and the refrigerant charge can be reduced.

Embodiment 7 FIG. Next, a seventh embodiment will be described with reference to FIG. Note that the same or corresponding portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be simplified. The seventh embodiment differs from the first embodiment in that the heat pump type air conditioner is a separate type, and is basically different in that the refrigerant flow control device is configured for cooling and heating.

That is, the heat pump type air conditioner is separated into an outdoor unit A and an indoor unit B. The outdoor unit A houses a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a first refrigerant flow control device 5a described later, and a first check valve 52. The indoor unit B includes an indoor heat exchanger 6 and a second refrigerant flow control device 5b.
And the second check valve 53 are housed.

The refrigerant flow control device in this refrigerant circuit comprises a first refrigerant flow control device 5a in which a first check valve 52 for blocking the flow of refrigerant from the outdoor heat exchanger 3 is connected in parallel.
Is connected in series to the first refrigerant flow control device 5a,
The second refrigerant flow control device 5b is connected in parallel with a second check valve 53 that allows the flow of the refrigerant from the first refrigerant flow control device 5a. Therefore, the refrigerant flow direction during the cooling operation is the direction of the solid arrow, and the high-pressure gas refrigerant compressed by the compressor 1 is cooled by the outdoor heat exchanger 3 and depressurized by the first refrigerant flow control device 5a. The refrigerant flows in the liquid-side connection pipe 31 in a gas-liquid two-phase state. Then, the second refrigerant flows through the second check valve 53 without flowing through the second refrigerant flow control device 5 b installed in the indoor unit B, and flows into the indoor heat exchanger 6. On the other hand, the refrigerant flow direction during the heating operation is the direction of the dotted arrow, and the high-pressure gas refrigerant compressed by the compressor 1 flows in the gas-side connection pipe 32, condenses and liquefies in the indoor heat exchanger 6, and 2 Refrigerant flow control device 5
The pressure is reduced at b, and flows in the liquid side connection pipe 31 in a gas-liquid two-phase state. And it flows through the first check valve 52 without flowing through the first refrigerant flow control device 5a installed in the outdoor unit A,
It flows into the outdoor heat exchanger 3.

During the cooling / heating operation, the refrigerant flow controllers 5a and 5b are controlled in the same manner as in the first embodiment. That is, during the cooling operation, the refrigerant subcooling degree at the condenser outlet is determined from the condensing temperature Tc detected by the intermediate temperature detector 8 of the outdoor heat exchanger 3 and the liquid refrigerant temperature Tq detected by the outlet temperature detector 9. Tqs is calculated, and this refrigerant subcooling degree T
The controller 27 controls the first refrigerant flow controller 5a based on the refrigerant subcooling degree Tqs so that qs becomes the above-described set value. During the heating operation, the refrigerant condensing temperature Tc detected by the intermediate temperature detector 10 of the indoor heat exchanger 6 and the liquid refrigerant temperature Tq detected by the outlet temperature detector 11
, The supercooling degree Tqs of the refrigerant at the outlet of the condenser is calculated, and the control device 27 controls the second refrigerant flow control device based on the supercooling degree Tqs so that the supercooling degree Tqs becomes the above-mentioned set value. 5b.

Therefore, the refrigerant always flows in the gas-liquid two-phase state in the liquid-side connection pipe 31 in both the cooling and heating operations, so that the amount of refrigerant in the liquid-side pipe can be reduced. When the pipe length is long, the effect of reducing the amount of refrigerant can be further exhibited.

Embodiment 8 FIG. Next, an eighth embodiment will be described with reference to FIG. Note that the same or corresponding portions as those in the first embodiment are denoted by the same reference numerals, and description thereof will be simplified. In the eighth embodiment, in the heat pump type air conditioner of the first embodiment, auxiliary pressure reducers 54 and 55 such as a capillary tube are provided before and after the refrigerant flow control device 5 (electric expansion valve). Further, a first refrigerant distributor 56 having a small pipe diameter is provided at the inlet of the outdoor heat exchanger 3 when acting as an evaporator, and further, the inlet of the indoor heat exchanger 6 when acting as an evaporator. Is provided with a second refrigerant distributor 57 having a small diameter. Therefore, in this case, the refrigerant flow control device 5 used has a larger diameter than that of the first embodiment.

Hereinafter, the operation will be described. As described in the first embodiment, when the R32 refrigerant is used, the discharge pressure and the discharge gas temperature of the refrigeration cycle are higher than when R22 is used as in the related art, and the pressure difference between the discharge pressure and the suction pressure. And the pressure drop in the refrigerant flow control device 5 also increases. Therefore, in the case of the first embodiment, if the refrigerant flow control device 5, which is an electric expansion valve, malfunctions and is fully opened, a predetermined reduced pressure drop in the refrigerant flow control device 5 cannot be secured. In addition, there is a possibility that extreme liquid return will occur in the compressor 1. However, in the case of the present embodiment, since the first auxiliary pressure reducer 54, the second auxiliary pressure reducer 55, the first refrigerant distributor 56, and the second refrigerant distributor 57 are provided, the refrigerant flow controller 5 Has a refrigerant flow rate control function in a certain range even if it malfunctions,
An extreme liquid return operation to the compressor 1 does not occur, and it is possible to prevent an operation state that has a serious effect such as causing the compressor 1 to break down. In addition, the refrigerant flow control device 5
, The value to be reduced becomes smaller, and the reliability of the main refrigerant flow controller 5 is also improved.

The present invention can be embodied with the following modifications. (1) In Embodiment 1, the number of passes and the heat transfer tubes between the inlet side portions 3a, 6a and the outlet side portions 3b, 6b when acting as condensers of the outdoor heat exchanger 3 and the indoor heat exchanger 6 The difference between the tube diameters is not limited to the above, and can be changed as appropriate.

(2) In each of the embodiments, the refrigerant that can be used is G32 in addition to R32 and R290.
R41, R143, R152a, R245c of 32 or less
HFC refrigerants such as a, HC refrigerants such as butane, isobutane, ethane and propylene having a GWP of R32 or less, and air, carbon dioxide gas having a GWP of R32 or less,
A natural refrigerant such as ammonia may be used. Even if a mixture of several kinds of these refrigerants is used, any refrigerant having a low refrigerant liquid density, a low global warming potential, and a low GWP effect can be used. In addition, HF with GWP of R32 or less
The C-based refrigerant, the HC-based refrigerant, the HE-based refrigerant, the FC-based refrigerant, or the natural-based refrigerant may be mixed with a refrigerant having a GWP of R32 or more, and the mixed refrigerant may have a GWP of 900 or less. In addition, the refrigerating machine oil for the various refrigerants described above,
Even if an ester oil, an ether oil, a fluorine oil, a mineral oil, or the like is used, its reliability is sufficiently ensured.

(3) Embodiments 1, 2, 6, 7, and 8
Is provided with a direct detection means for directly detecting the refrigerant subcooling degree Tqs at the outlet of the condenser. Superheat degree Ts of compressor suction gas when outer heat exchanger 3 or indoor heat exchanger 6 acts as an evaporator
s, the degree of superheating Tds of the compressor discharge gas or the degree of dryness i of the compressor suction gas, etc., and is set so that the degree of supercooling of the refrigerant Tqs at the outlet of the condenser becomes substantially a set value. The opening degree of the refrigerant flow control device 5 may be controlled based on the detection value detected by the above.

(4) Embodiments 1, 2, 4, 6, 7,
8, an intermediate temperature detector 8 for detecting the refrigerant condensation temperature Tc and an outlet temperature detector 9 for detecting the liquid refrigerant temperature Tq as direct detection means for directly detecting the refrigerant subcooling degree Tqs at the condenser outlet. Although provided, instead of the intermediate temperature detector 8, a means for measuring the condensing pressure or the discharge pressure Pd and a means for calculating the saturation temperature from the pressure Pd may be provided.

(5) In the third embodiment, the superheat degree Td of the compressor discharge gas described in the third embodiment
Instead of detecting the s, the discharge pressure Pd of the compressor and the discharge gas temperature Td of the compressor are detected, and these detected values Pd,
The discharge gas superheat degree Tds of the compressor may be calculated from Td.

(6) In the eighth embodiment, the auxiliary pressure reducer 5 is provided on each of the upstream side and the downstream side of the refrigerant flow control device 5.
4 and 55, and a first refrigerant distributor 56 and a second refrigerant distributor 57 are provided on the inlet side of the outdoor heat exchanger 3 and the indoor heat exchanger 6 when acting as evaporators. Although the above examples have been described, only one of them may be used.

(7) In the refrigeration and air-conditioning system shown in each of the above embodiments, the compressor is of any type, for example,
Any of a reciprocating compressor (single cylinder, plural cylinders), a rotary compressor (single cylinder, plural cylinders), a scroll compressor, a linear compressor and the like may be used.

(8) In the refrigerating and air-conditioning apparatuses shown in the above embodiments, the outdoor heat exchanger 3 and the indoor heat exchanger 6 are of the plate fin tube type.
A corrugated fin tube type may be used. Since this heat exchanger is manufactured by brazing in a furnace, brazing is completed in one time and brazing is not performed several times as in the plate fin tube type, so the probability of refrigerant leakage due to poor brazing is low. Therefore, safety when using a refrigerant having a combustible property can be further secured. Further, since the corrugated fin tube type heat exchanger is made of the same material such as aluminum, it has excellent recyclability.

Next, although not directly related to each of the above embodiments, its peripheral technology will be described. First, a leak detection method when a flammable refrigerant is used will be described. R2
90 (propane) is used as domestic fuel, and if any measures can be taken so that this gas leak detector can detect refrigerant leakage from the domestic refrigeration / air-conditioning device, it is used exclusively for domestic refrigeration / air-conditioning devices. It is not necessary to add the refrigerant leak detection device, and a safe refrigeration and air conditioning device can be provided at low cost. Further, an example of an application system in this case will be further described. In a gas leak detector for fuel using a household power line, the power line is used as a communication line, and refrigerant leak detection information is put on the power line by a power line communication interface. At this time, in the power line communication interface, the address including the address of the transmitting device, the address of the destination device, and the content including the information to be transmitted are transmitted, and these digital signals are converted into analog signals for putting on the power line. Is provided. In addition, household refrigeration and air conditioning equipment connected to the power line,
It is equipped with a communication interface that extracts the address of the transmitting device, the address of the destination device, and information to be transmitted from various analog signals carried on the power line. And
This communication interface is also provided with a function of converting an analog signal into a digital signal. Then, by transmitting a signal to a device for controlling each actuator of the refrigeration / air-conditioning device based on the digital signal, a measure corresponding to the refrigerant leakage is taken, such as stopping the compressor or warning and displaying the refrigerant leakage. be able to.

Next, a case will be described in which a dedicated device for detecting a refrigerant leak is installed without using the refrigerant leak detector and the gas leak detector for fuel. When the refrigerant leaks, the refrigerant leak detector should be placed in the place where the refrigerant is most likely to stagnate when the refrigerant leaks, so it is not necessarily built into the refrigeration air conditioner or around the refrigeration air conditioner. It is not necessarily installed. Therefore, it is necessary to exchange information on the detected information between the refrigerant leak detection device and the refrigeration / air-conditioning device. In this case, if the above-described power line is used as a communication line and the above-described communication interface corresponding to the electric line is used, a safe refrigeration and air-conditioning apparatus can be provided at low cost without additional wiring. In the above description, an example in which a power line is used as a communication line has been described. Instead of such a power line communication interface, a telephone line communication interface or a wireless communication interface using infrared rays or the like may be provided.

[0088]

Since the present invention is configured as described above, it has the following effects. According to the refrigeration / air-conditioning apparatus of the present invention, in a refrigeration / air-conditioning apparatus including a compressor, a condenser, a refrigerant flow control device, and a refrigerant circuit in which an evaporator is connected by a refrigerant pipe, a flammable refrigerant is used as a refrigerant, Direct detection means for directly detecting the refrigerant subcooling degree at the condenser outlet; and refrigerant flow rate control based on the detection value detected by the direct detection means so that the refrigerant subcooling degree at the condenser outlet becomes substantially a set value. Since the control device for controlling the opening degree of the device is provided, unnecessary accumulation of the liquid refrigerant having a large influence on the determination of the refrigerant charging amount is eliminated, and the refrigerant charging amount is reduced. In addition, the COP is improved by subcooling the liquid refrigerant at the condenser outlet, thereby also reducing the refrigerant charge. Therefore, safety when using a combustible refrigerant that does not cause ozone destruction or global warming can be improved.

According to the refrigeration / air-conditioning apparatus of the present invention, there is provided a refrigeration / air-conditioning apparatus having a refrigerant circuit in which a compressor, a condenser, a refrigerant flow control device, and an evaporator are connected by refrigerant piping.
While using a flammable refrigerant as the refrigerant, an alternative detection unit that detects a refrigerant physical property value that changes according to the refrigerant subcooling degree at the condenser outlet, and the refrigerant subcooling degree at the condenser outlet becomes substantially a set value. As described above, since the control device for controlling the opening of the refrigerant flow control device based on the detection value detected by the alternative detection means is provided, the same effect as described above can be obtained.

Further, according to the refrigeration / air-conditioning apparatus of the present invention, in a refrigeration / air-conditioning apparatus provided with a refrigerant circuit in which a variable displacement compressor, a condenser, a refrigerant flow controller and an evaporator are connected by refrigerant piping, combustion as a refrigerant is performed. And a direct detection unit for directly detecting the degree of subcooling of the refrigerant at the outlet of the condenser, and the degree of subcooling of the refrigerant at the outlet of the condenser is substantially set to be detected by the detecting unit. Since the control device for controlling the compressor capacity based on the detected value is provided, the same effects as described above and above can be obtained in this case.

Further, according to the refrigeration / air-conditioning apparatus of the present invention, in the refrigeration / air-conditioning apparatus provided with a refrigerant circuit in which a variable displacement compressor, a condenser, a refrigerant flow control device and an evaporator are connected by refrigerant piping, combustion as a refrigerant is performed. With the use of a refrigerant having a property, an alternative detection unit that detects a refrigerant physical property value that changes in accordance with the degree of subcooling of the refrigerant at the condenser outlet, and the degree of subcooling of the refrigerant at the condenser outlet becomes substantially the set value. Since the control device for controlling the compressor capacity based on the detection value detected by the alternative detection means is provided, the same effect as described above can be obtained in this case as well.

In the refrigeration / air-conditioning apparatus of the present invention,
Since the outlet of the condenser and the refrigerant flow rate control device are connected only by the refrigerant pipe without passing through the container for storing the refrigerant, the volume of the space where the liquid refrigerant is stored is reduced,
The amount of refrigerant charged can be further reduced.

In the refrigeration / air-conditioning apparatus of the present invention,
Since the outlet of the evaporator and the compressor suction side are connected only by the refrigerant pipe without passing through a container for storing the refrigerant, the volume of the space where the liquid refrigerant is stored is reduced, and the amount of refrigerant charged is reduced. can do.

In the refrigeration / air-conditioning apparatus of the present invention,
The condenser is a heat exchanger of a type in which a high-pressure refrigerant flows through the inside of the heat transfer tube, and the high-pressure refrigerant and a cooling source outside the heat transfer tube exchange heat, and a refrigerant flow area on the condenser outlet side. Is made smaller than the refrigerant flow area on the inlet side of the condenser, the volume of the portion where the supercooled liquid refrigerant accumulates is reduced, and the amount of charged refrigerant can be further reduced. In addition, this makes it possible to obtain a refrigeration / air-conditioning apparatus in which the probability of ignition in the case of refrigerant leakage is reduced and safety is enhanced. In addition, since the flow rate of the refrigerant increases at the outlet side of the condenser, the heat transfer coefficient on the refrigerant side in the heat transfer tube is improved, and the COP of the refrigeration air conditioner can be improved. Therefore, the liquid refrigerant filling amount is reduced by reducing the volume of the portion where the liquid refrigerant is stored, and
It is possible to further reduce the amount of refrigerant to be charged by improving the COP and reducing the size of the refrigeration / air-conditioning apparatus.

In the refrigerating and air-conditioning apparatus of the present invention,
As a configuration in which the refrigerant flow area on the condenser outlet side is smaller than the refrigerant flow area on the condenser inlet side, the inner diameter of the heat transfer tube on the condenser outlet side is made smaller than the inner diameter of the heat transfer tube on the condenser inlet side. Alternatively, since the inner diameter of the heat transfer tube on the condenser outlet side is smaller than the inner diameter of the heat transfer tube on the condenser inlet side, the refrigerant flow area on the condenser outlet side is smaller than the refrigerant flow area on the condenser inlet side. A small configuration can be easily realized.

In the refrigeration / air-conditioning apparatus of the present invention,
Since the inside diameter of the pipe connecting the condenser outlet and the refrigerant flow control device is smaller than the inside diameter of the heat transfer tube of the condenser, the volume of the part where the supercooled liquid refrigerant formed between the condenser and the evaporator is accumulated is reduced. It is possible to obtain a refrigeration / air-conditioning apparatus that can be reduced in size, can further reduce the amount of charged refrigerant, and can further reduce the probability of ignition in the event of leakage of the refrigerant, thereby further enhancing safety.

In the refrigeration / air-conditioning apparatus of the present invention,
Since the direct detection means directly detects the degree of refrigerant subcooling from the difference between the refrigerant temperature at the intermediate portion of the condenser and the refrigerant temperature at the outlet of the condenser, it is possible to reliably and accurately detect the degree of refrigerant subcooling. it can.

In the refrigeration / air-conditioning apparatus of the present invention,
Instead of the direct detection means, the refrigerant physical property value detected by the alternative detection means may be a superheat degree of a compressor suction gas, a superheat degree of a compressor discharge gas, or a dryness of a compressor suction gas.

In the refrigeration / air-conditioning apparatus of the present invention,
When the refrigerant circuit is filled with R32, the approximate set value of the degree of subcooling of the refrigerant is in the range of 5 to 20 ° C.,
Ozone layer destruction and global warming due to refrigerant discharge can be prevented. In addition, since the degree of supercooling at the outlet of the condenser is controlled to an optimum value, the ratio of the amount of liquid refrigerant in the refrigerant circuit, which has a great influence on the amount of charged refrigerant, is minimized, and the COP of the refrigeration and air conditioning system is improved. . As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved.

In the refrigeration / air-conditioning apparatus of the present invention,
The refrigerant circuit is filled with R32 as a refrigerant, and when the degree of superheat of the compressor discharge gas is a set value of 40 ° C or less, the substantially set value of the degree of subcooling of the refrigerant is in the range of 5 to 20 ° C. As described above, the capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charging amount are combined, and the control device sets the superheat degree of the compressor discharge gas substantially to the setting of the superheat degree of the discharge gas. Since the refrigerant flow control device is controlled so as to be a value, destruction of the ozone layer due to refrigerant discharge and global warming can be prevented. Also, the degree of supercooling at the condenser outlet is controlled to an optimum value, the discharge gas temperature is appropriately controlled,
The ratio of the amount of liquid refrigerant in a refrigerant circuit having a large influence on the amount of charged refrigerant is minimized, and the COP of the refrigeration and air conditioning system is improved. As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved. At the same time, it is possible to prevent overheating damage to electric equipment such as a compressor motor.

In the refrigeration / air-conditioning apparatus of the present invention,
The refrigerant circuit is filled with R32 as a refrigerant, and when the dryness of the compressor suction gas is a set value of 1 or less, the substantially set value of the refrigerant subcooling is in the range of 5 to 20 ° C. As described above, the capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charging amount are combined, and the control device makes the dryness of the compressor suction gas substantially equal to the dryness set value. Since the refrigerant flow control device is controlled in advance, destruction of the ozone layer and global warming due to refrigerant discharge can be prevented. In addition, by returning the wet refrigerant to the compressor, the temperature rise of the discharged gas is suppressed, and the degree of supercooling at the condenser outlet is controlled to an optimum value. The ratio of the amount of the refrigerant is minimized, and the COP of the refrigeration and air conditioning system is improved. As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved. At the same time, it is possible to prevent overheating damage to electric equipment such as a compressor motor.

Further, in the refrigeration / air-conditioning apparatus of the present invention,
The refrigerant circuit is filled with R290 as a refrigerant, and the substantially set value of the subcooling degree of the refrigerant is in a range of 5 to 17 ° C, so that the ozone layer can be prevented from being destroyed due to refrigerant discharge and global warming can be prevented. In addition, since the degree of subcooling of the refrigerant is controlled to the optimum value, the ratio of the amount of liquid refrigerant in the refrigerant circuit that has a great influence on the amount of charged refrigerant is minimized, and the COP of the refrigeration and air conditioning system is improved. As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved.

In the refrigeration / air-conditioning apparatus of the present invention,
The refrigerant circuit is filled with R290 as a refrigerant, and the superheat degree of the compressor suction gas is set at 0 ° C. or more, and the substantially set value of the refrigerant subcooling degree is in the range of 5 to 17 ° C. In addition, the capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charging amount are combined, and the control device determines that the superheat degree of the compressor intake gas is substantially equal to the superheat degree of the compressor intake gas. Since the refrigerant flow control device is controlled to be the set value, it is possible to prevent ozone layer destruction and global warming due to refrigerant discharge. In addition, by controlling the degree of subcooling of the refrigerant to the optimum value and maintaining the compressor discharge gas temperature Td at an appropriate level, the ratio of the amount of liquid refrigerant in the refrigerant circuit, which has a large effect on the amount of refrigerant charged, can be minimized. Limit,
Improve the COP of refrigeration and air conditioning equipment. As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved. In addition, it is possible to prevent the temperature of the hot air from decreasing during the heating operation while using R290.

Further, in the refrigeration / air-conditioning apparatus of the present invention,
The refrigerant circuit is filled with R290 as a refrigerant, and when the degree of superheat of the compressor discharge gas is a set value of 15 to 40 ° C, the approximate set value of the refrigerant supercooling degree is 5 to 17 ° C.
The capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charge amount are combined so as to be within the range described above, and the control device makes the superheat degree of the compressor discharge gas substantially equal to the discharge gas. Since the refrigerant flow control device is controlled so as to achieve the set value of the superheat degree, destruction of the ozone layer and global warming due to refrigerant release can be prevented. In addition, the refrigerant supercooling degree is controlled to an optimum value, and the compressor discharge gas temperature T
By appropriately maintaining d, the ratio of the amount of liquid refrigerant in the refrigerant circuit, which has a large effect on the amount of charged refrigerant, is minimized, and the COP of the refrigeration and air conditioning system is improved. As a result, the amount of refrigerant charged into the refrigerant circuit is further reduced, and the safety of the refrigerating air conditioner against combustion can be further improved. In addition, it is possible to prevent the temperature of the hot air from decreasing during the heating operation while using R290.

Further, the above-described supercooling degree of the refrigerant, the superheat degree of the compressor suction gas, and the superheat degree of the compressor discharge gas are controlled within a range of about ± 1 ° C. or less with respect to the set values. Fluctuations in required refrigerant amount are reduced, fluctuations in required refrigerant amount due to changes in operating conditions are reduced, liquid return and abnormal rise in superheat of intake gas are prevented, and the amount of refrigerant charged into the refrigerant circuit is further reduced. be able to.

According to the heat pump refrigeration / air-conditioning apparatus of the present invention, the high pressure port of the four-way valve is connected to the discharge side of the compressor, and the low pressure port of the four-way valve is connected to the suction side of the compressor. A heat source side heat exchanger, a refrigerant flow control device, and a use side heat exchanger are sequentially connected between the two switching ports of the four-way valve. The refrigerant supercooling degree at the outlet of the side heat exchanger is controlled to be substantially a set value, and the second refrigerant flow control device controls the refrigerant supercooling at the outlet of the use side heat exchanger when performing the heating operation with the four-way valve as a heating cycle. Since the degree of cooling is controlled to be substantially the set value, the volume of the portion where the liquid refrigerant is stored is reduced and the COP is improved in either the cooling or heating operation, as in the case of the above-described refrigeration and air conditioning system. , It is possible to reduce the refrigerant charge.

Further, in the heat pump type refrigeration / air-conditioning apparatus of the present invention, an auxiliary pressure reducer is provided either before or after or before and after the refrigerant flow control device.
In addition to the effects described above, even if an accident occurs in which the refrigerant flow control device becomes inactive and is fully opened, an extreme liquid return operation can be prevented, and the reliability of the device is improved.

According to the heat pump refrigeration / air-conditioning apparatus of the present invention, the high pressure port of the four-way valve is connected to the discharge side of the compressor, and the low pressure port of the four-way valve is connected to the suction side of the compressor. A heat source side heat exchanger between the two switching ports of the four-way valve, a first refrigerant flow control device in which a first check valve for preventing the flow of refrigerant from the heat source side heat exchanger is connected in parallel,
A second refrigerant flow control device in which a second check valve allowing the flow of refrigerant from the first refrigerant flow control device is connected in parallel, and a use-side heat exchanger are sequentially connected, and the first refrigerant flow control device is connected to the four-way valve. When performing the cooling operation with the valve as the cooling cycle, the refrigerant supercooling degree at the heat source side heat exchanger outlet is controlled to be substantially the set value, and the second refrigerant flow control device performs the heating operation with the four-way valve as the heating cycle. In this case, since the degree of subcooling of the refrigerant at the outlet of the use side heat exchanger is controlled to be substantially the set value, in addition to the effect of reducing the amount of refrigerant charged similarly to the above-described heat pump refrigeration / air-conditioning apparatus, By making the refrigerant pipe connecting the heat source side heat exchanger and the use side heat exchanger into a gas-liquid two-phase flow, the amount of refrigerant charged is further reduced, and the ignition establishment at the time of refrigerant leakage is lowered and safety is improved. Can be enhanced.

[Brief description of the drawings]

FIG. 1 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram describing data indicating an optimal degree of supercooling of the refrigeration / air-conditioning apparatus according to Embodiment 1 of the present invention.

FIG. 3 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 2 of the present invention.

FIG. 4 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 3 of the present invention.

FIG. 5 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 4 of the present invention.

FIG. 6 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 5 of the present invention.

FIG. 7 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 6 of the present invention.

FIG. 8 is a refrigerant circuit diagram of a refrigeration / air-conditioning apparatus according to Embodiment 7 of the present invention.

FIG. 9 is a refrigerant circuit diagram of a refrigeration and air-conditioning apparatus according to Embodiment 8 of the present invention.

FIG. 10 is a refrigerant circuit diagram of a conventional refrigeration / air-conditioning apparatus.

[Explanation of symbols]

1 compressor, two-way valve, 2a high pressure port, 2b low pressure port, 2c, 2d switching port, 3 outdoor heat exchanger (heat source side heat exchanger), 3a inlet side, 3b outlet side,
5, refrigerant flow control device, 5a first refrigerant flow control device, 5b second refrigerant flow control device, 6 indoor heat exchanger (use side heat exchanger), 6a inlet side, 6b outlet side, 8, 10 Intermediate temperature detector, 9, 11 Outlet temperature detector, 12 Outside air temperature detector, 13 Indoor air temperature detector, 21, 23-27 Control device, 31 Liquid side connection pipe, 32 Gas side connection pipe, 51 Refrigerant flow rate control apparatus,
52, 53 Check valve, 54, 55 Auxiliary pressure reducer, A outdoor unit, B indoor unit, i Dryness of compressor intake gas, Tai indoor air temperature, Tao outdoor air temperature, Tc refrigerant condensing temperature, Td compressor discharge Gas temperature,
Tds Superheat degree of compressor discharge gas, Te refrigerant evaporation temperature, Tq liquid refrigerant temperature, Tqs refrigerant subcooling degree, Ts
Compressor intake gas temperature, Tss Superheat degree of compressor intake gas.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kosuke Makino 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 3L092 AA11 AA14 BA01 BA15 DA14 EA04 EA06 FA03 FA26

Claims (26)

[Claims] In a refrigeration air conditioner provided with a refrigerant circuit in which a compressor, a condenser, a refrigerant flow control device, and an evaporator are connected by refrigerant piping, a flammable refrigerant is used as a refrigerant and a refrigerant at a condenser outlet is provided. The direct detection means for directly detecting the degree of subcooling, and the opening degree of the refrigerant flow control device based on the detection value detected by the direct detection means so that the degree of supercooling of the refrigerant at the condenser outlet becomes substantially a set value. A refrigeration / air-conditioning apparatus, comprising: a control device for controlling. 2. A refrigeration air conditioner having a refrigerant circuit in which a compressor, a condenser, a refrigerant flow control device, and an evaporator are connected by refrigerant pipes, wherein a flammable refrigerant is used as a refrigerant and a refrigerant at a condenser outlet is used. Substitution detection means for detecting a refrigerant physical property value that changes in accordance with the degree of subcooling, and a refrigerant flow rate based on the detection value detected by the substitution detection means such that the degree of supercooling of the refrigerant at the condenser outlet becomes substantially a set value. A refrigeration / air-conditioning apparatus comprising: a control device that controls an opening of the control device. 3. A refrigeration and air-conditioning system comprising a variable displacement compressor, a condenser, a refrigerant flow controller and a refrigerant circuit in which an evaporator is connected by refrigerant piping, wherein a flammable refrigerant is used as a refrigerant, Direct detection means for directly detecting the degree of subcooling of the refrigerant at the outlet; and controlling the compressor capacity based on the detection value detected by the detecting means so that the degree of subcooling of the refrigerant at the condenser outlet becomes substantially a set value. A refrigeration / air-conditioning device comprising a control device. 4. A refrigeration / air-conditioning system including a variable displacement compressor, a condenser, a refrigerant flow control device, and a refrigerant circuit in which an evaporator is connected by refrigerant piping, wherein a flammable refrigerant is used as a refrigerant, and Alternative detection means for detecting a refrigerant physical property value that changes in accordance with the refrigerant subcooling degree at the outlet, and the detection value detected by the alternative detection means so that the refrigerant supercooling degree at the condenser outlet becomes substantially a set value. And a control device for controlling a compressor capacity based on the refrigerating air conditioner. 5. The refrigerant flow control device according to claim 1, wherein an outlet of the condenser and the refrigerant flow control device are connected only by a refrigerant pipe without passing through a container for storing the refrigerant. A refrigeration / air-conditioning apparatus according to the item. 6. The air conditioner according to claim 1, wherein an outlet of the evaporator and a compressor suction side are connected only by a refrigerant pipe without passing through a refrigerant liquid reservoir. Refrigeration air conditioner. 7. The condenser is a heat exchanger in which a high-pressure refrigerant flows through a heat transfer tube, and the high-pressure refrigerant exchanges heat with a cooling source outside the heat transfer tube. The refrigeration / air-conditioning apparatus according to any one of claims 1 to 6, wherein the refrigerant circulation area of the portion is smaller than the refrigerant circulation area of the condenser inlet side. 8. A configuration in which the refrigerant flow area on the condenser outlet side is smaller than the refrigerant flow area on the condenser inlet side,
The refrigeration / air-conditioning apparatus according to claim 7, wherein the inner diameter of the heat transfer tube at the outlet side of the condenser is smaller than the inner diameter of the heat transfer tube at the inlet side of the condenser. 9. A configuration in which the refrigerant flow area on the condenser outlet side is smaller than the refrigerant flow area on the condenser inlet side,
The refrigeration / air-conditioning apparatus according to claim 7, wherein the number of refrigerant flow paths on the condenser outlet side is smaller than the number of refrigerant flow paths on the condenser inlet side. 10. The refrigeration / air-conditioning apparatus according to claim 1, wherein an inner diameter of a pipe connecting the outlet of the condenser and the refrigerant flow control device is smaller than an inner diameter of a heat transfer pipe of the condenser. . 11. The method according to claim 1, wherein the direct detection means directly detects the degree of subcooling of the refrigerant from a difference between the refrigerant temperature at the intermediate portion of the condenser and the refrigerant temperature at the outlet of the condenser.
Or the refrigeration / air-conditioning apparatus according to 3. 12. The refrigeration / air-conditioning apparatus according to claim 2, wherein the refrigerant physical property value detected by the substitute detection means is a degree of superheat of a compressor suction gas. 13. The refrigeration / air-conditioning apparatus according to claim 2, wherein the refrigerant physical property value detected by the substitute detection means is a degree of superheat of a compressor discharge gas. 14. The refrigeration / air-conditioning apparatus according to claim 2, wherein the refrigerant physical property value detected by the substitute detection means is a dryness of a compressor suction gas. 15. The refrigerant circuit according to claim 1, wherein R32 is filled as a refrigerant, and a substantially set value of the degree of subcooling of the refrigerant is in a range of 5 to 20 ° C. A refrigeration / air-conditioning apparatus according to claim 1. 16. The refrigerant circuit is filled with R32 as a refrigerant and has a superheat degree of a compressor discharge gas of 40 ° C.
When the following set value is set, the approximate set value of the refrigerant subcooling degree is 5
The capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charging amount are combined so as to be within the range of ２０20 ° C., and the control device substantially superheats the compressor discharge gas. 14. The refrigeration / air-conditioning apparatus according to claim 13, wherein the refrigerant flow control device is controlled so that the superheat degree of the discharge gas becomes a set value. 17. The refrigerant circuit is filled with R32 as a refrigerant and has a dryness of a compressor suction gas of 1%.
When the following set value is set, the approximate set value of the refrigerant subcooling degree is 5
The temperature of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charge amount are combined so as to fall within the range of ~ 20 ° C. The refrigeration / air-conditioning apparatus according to claim 14, wherein a refrigerant flow control device is controlled so as to be the dryness set value. 18. The refrigerant circuit according to claim 1, wherein R290 is filled as a refrigerant, and a substantially set value of the degree of subcooling of the refrigerant is in a range of 5 to 17 ° C. A refrigeration / air-conditioning apparatus according to claim 1. 19. The refrigerant circuit, wherein R290 is used as a refrigerant.
Is filled, and the superheat degree of the compressor suction gas is set to 0 ° C. or more, and the substantially set value of the refrigerant supercooling degree is 5 to 5.
The capacity of the compressor, the size of the condenser, the size of the evaporator, and the refrigerant charging amount are combined so as to be within the range of 17 ° C., and the control device controls the superheat degree of the compressor suction gas to be approximately 13. The refrigeration / air-conditioning apparatus according to claim 12, wherein the refrigerant flow control device is controlled so as to have a set value of the degree of superheat of the compressor suction gas. 20. The refrigerant circuit, wherein R290 is used as a refrigerant.
And the compressor is set such that when the degree of superheat of the gas discharged from the compressor is a set value of 15 to 40 ° C., the substantially set value of the degree of subcooling of the refrigerant is in the range of 5 to 17 ° C. The capacity of the condenser, the size of the condenser, the size of the evaporator, and the refrigerant charge amount are combined, and the control device controls the refrigerant so that the superheat degree of the compressor discharge gas becomes substantially the set value of the superheat degree of the discharge gas. The refrigeration / air-conditioning apparatus according to claim 13, wherein the refrigeration / air-conditioning apparatus controls a flow rate control device. 21. The refrigeration / air-conditioning apparatus according to claim 1, wherein the refrigerant supercooling degree is controlled within a range of about ± 1 ° C. or less with respect to a set value thereof. 22. The refrigeration / air-conditioning apparatus according to claim 19, wherein the degree of superheat of the compressor suction gas is controlled within a range of about ± 1 ° C. or less with respect to a set value thereof. 23. The refrigeration / air-conditioning apparatus according to claim 16, wherein the degree of superheat of the compressor discharge gas is controlled within a range of about ± 1 ° C. or less with respect to a set value thereof. 24. A high-pressure port of a four-way valve is connected to a discharge side of the compressor, and a low-pressure port of a four-way valve is connected to a suction side of the compressor, and a heat source side is provided between two switching ports of the four-way valve. The heat exchanger, the refrigerant flow control device, and the use side heat exchanger are sequentially connected, and the refrigerant flow control device substantially reduces the degree of subcooling of the refrigerant at the heat source side heat exchanger outlet when performing the cooling operation using the four-way valve as a cooling cycle. The refrigerant flow control device is controlled to be a set value, and the refrigerant flow rate control device is controlled to make the refrigerant subcooling degree at the outlet of the use side heat exchanger substantially equal to the set value when performing the heating operation with the four-way valve as a heating cycle. A heat pump refrigeration and air conditioning system characterized by the following. 25. The heat pump type refrigerating and air-conditioning apparatus according to claim 24, wherein an auxiliary pressure reducer is provided at one or both of the front and rear of the refrigerant flow control device. 26. A high-pressure port of a four-way valve is connected to a discharge side of the compressor, and a low-pressure port of a four-way valve is connected to a suction side of the compressor, and a heat source side is provided between two switching ports of the four-way valve. A heat exchanger, a first refrigerant flow control device connected in parallel with a first check valve for preventing a refrigerant flow from the heat source side heat exchanger, and a second reverse flow allowing the refrigerant flow from the first refrigerant flow control device A second refrigerant flow control device in which stop valves are connected in parallel, and a use side heat exchanger are sequentially connected, and the first refrigerant flow control device is a heat source side heat exchanger when performing a cooling operation using the four-way valve as a cooling cycle. The refrigerant supercooling degree at the outlet is controlled to be substantially a set value, and the second refrigerant flow control device sets the refrigerant subcooling degree at the use-side heat exchanger outlet when performing the heating operation with the four-way valve as a heating cycle. It is controlled so as to be approximately the set value. Heat pump refrigeration air conditioner.