JPS637314B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an air conditioner in which a refrigeration cycle is configured using a thermostatic reversible expansion valve.

[Technical background of the invention and its problems]

BACKGROUND ART As for air conditioners that perform heating and cooling, there are known ones in which a temperature-type reversible flow expansion valve is provided in a refrigerant path connecting an indoor heat exchanger and an outdoor heat exchanger that constitute a refrigeration cycle. Since heat pumps use different evaporators for cooling and heating, the temperature on the suction side of the compressor, which corresponds to the evaporator outlet, is constantly sensed to change the throttle amount of the temperature-type reversible expansion valve. The required refrigeration cycle capacity is obtained by changing the amount.

By the way, a refrigeration cycle employing this type of thermostatic reversible expansion valve is disclosed in Japanese Patent Application Laid-open No. 56-59168,
As shown in Japanese Patent Application Laid-open Nos. 56-105263 and 1987-143365, those that are simply installed in series on the refrigerant path, including those that employ injection extensions, are used.

However, when operating a thermostatic reversible flow expansion valve, the amount of throttling is extremely large during cooling operations during low-load cooling operations, such as during the rainy season when the temperature is relatively low and humid. Heat exchangers have problems in that their temperature drops and freezes, causing them to lose their cooling capacity and dehumidification, making them unable to continue operating. In particular, the user misunderstood that there was a malfunction.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an air conditioner that can maintain cooling capacity even during low-load cooling operation.

[Summary of the invention]

This invention provides a refrigerant path having a temperature-type reversible flow expansion valve with a bypass path in which a pressure reducer having a resistance sufficient to exert a minimum cooling capacity is inserted in parallel to the temperature-type reversible flow expansion valve. During low-load operation, when the resistance of the thermostatic reversible expansion valve becomes greater than that of the pressure reducer, the refrigerant is circulated through the bypass passage to the extent that freezing does not occur in the indoor heat exchanger during low-load cooling operation. The aim is to introduce refrigerant.

[Embodiments of the invention]

The present invention will be described below based on an embodiment shown in the drawings. In the figure, 1 is a variable capacity compressor, 2
3 is a four-way valve, 3 is an indoor heat exchanger, 4 is a capillary, and 5 is an outdoor heat exchanger, and these devices are sequentially connected by a refrigerant path 6. Further, on the refrigerant path 6 connecting the indoor heat exchanger 3 and the outdoor heat exchanger 5, there is provided a temperature-type reversible flow expansion valve 8 with a heat-sensitive part 7a disposed on the suction side of the compressor 1. This constitutes a refrigeration cycle 9. On the other hand, 10 in the figure
A refrigerant path 6 connecting the outdoor heat exchanger 5 and the thermostatic reversible expansion valve 8 and a compression chamber of the compressor 1 (not shown)
A capillary 11 is provided on this injection exit path 10,
It constitutes an injection circuit 12.

On the other hand, 12 in the figure is a bypass path, and a pressure reducer, for example, a capillary 13 is provided on this bypass path 12. Each end of the bypass passage 12 is connected to the temperature type reversible expansion valve 8 and the refrigerant passages 6 on both sides of the injection passage 10, respectively, and the bypass passage 12 is connected in parallel to the temperature type reversible expansion valve 8. ing. And capillary 13
is the indoor heat exchanger 3 that serves as an evaporator during cooling operation.
It is constructed with enough resistance (throttle) to allow the refrigerant to flow without freezing, or in other words, enough resistance (throttling) to exert the minimum cooling capacity.

The bypass passage 12 is also provided with a check valve 14 as an opening/closing control valve that shuts off the flow toward the outdoor heat exchanger 5. During cooling operation, the resistance (throttling) of the thermostatic reversible expansion valve 8 is When the resistance (restriction) of the capillary 13 is greater, the refrigerant can flow through the bypass passage 12.

Note that in the drawings, 15 indicates a muffler.

When performing cooling using the air conditioner configured in this way, by operating the compressor 1, the compressor is adjusted by the throttle opening of the temperature-type reversible expansion valve 8 corresponding to changes in the cooling load. 1,
Four-way valve 2, outdoor heat exchanger 5, indoor heat exchanger 3
The refrigerant flow rate via the injection passage 10
Cooling capacity increased operation is performed in which the flow rates of refrigerant injected into the compression chamber of the compressor 1 are matched while changing each other.

In addition, the effect is the same for heating, only the flow of the refrigeration cycle is changed.

Therefore, in the above-mentioned cooling operation, in the case of low-load cooling operation such as when the rainy season is relatively low temperature and humid, the amount of throttling of the temperature-type reversible expansion valve 8 is significant, and the indoor heat is reduced. The exchanger 3 froze and caused various problems, but in this invention, even if the temperature-type reversible expansion valve 8 has a significant amount of restriction, the restriction of the temperature-type reversible-flow expansion valve 8 also increases the restriction of the capillary 13. By the way, depending on the magnitude of the resistance, the refrigerant is bypassed to the bypass path 12 and flows to the indoor heat exchanger 3 through the capillary 13 and the check valve 14. Here, since the capillary 13 allows the refrigerant to flow to the indoor heat exchanger 3 to an extent that does not cause freezing, a transition is made to the cooling operation that does not cause freezing. In this way, the cooling capacity can be maintained even during low-load cooling operation, and operation can be continued including the dehumidification effect, so there is no need to misunderstand that there is a failure.

〔Effect of the invention〕

As explained above, according to the present invention, cooling capacity can be maintained even during low cooling load operation.

Therefore, you can continue driving and there is no need to worry about misunderstandings.

[Brief explanation of the drawing]

The drawing is a configuration diagram showing an air conditioner according to an embodiment of the present invention. 3... Indoor heat exchanger, 5... Outdoor heat exchanger, 6... Refrigerant path, 8... Temperature type reversible flow expansion valve,
12... Bypass path, 13... Capillary (pressure reducer).

Claims (1)

[Claims] 1. In an air conditioner in which a temperature-type reversible flow expansion valve is provided in a refrigerant path connecting an indoor heat exchanger and an outdoor heat exchanger constituting a refrigeration cycle, the refrigerant path having the temperature-type reversible flow expansion valve is A bypass path in which a pressure reducer with a resistance sufficient to exert the minimum cooling capacity is inserted is provided in parallel with the temperature-type reversible expansion valve, so that the resistance of the temperature-type reversible expansion valve is reduced during low-load cooling operation. An air conditioner characterized in that the refrigerant is caused to flow through the bypass path when the resistance becomes greater than the resistance of the pressure reducing device.