JPS6340764Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to controlling the amount of refrigerant circulation during defrost operation during heating operation of a heat pump type air conditioner.

Normally, in a refrigeration cycle, the appropriate refrigerant flow rate varies depending on the evaporation temperature, and as the evaporation temperature increases, a larger refrigerant flow rate is required. When the adjustment width is small and the evaporation temperature is high, the refrigerant flow rate is insufficient, and the degree of superheating of the refrigerant at the evaporator outlet becomes too large, causing the compressor temperature to rise, and when the evaporation temperature is low, the refrigerant flow rate becomes excessive. This may cause liquid backlog in the compressor. Therefore, in order to solve these problems, a refrigeration cycle as shown in FIG. 1 has been considered. In other words, in Fig. 1, 1 is a compressor, 2 is a four-way switching valve, 3 is a non-use side heat exchanger that exchanges heat with outside air, 4 is a use side heat exchanger that exchanges heat with water, and 5 is a user side and non-use side heat exchanger. This is a pressure reducing device installed between the heat exchangers 4 and 3 on the user side, and as shown in FIG. Insert the tube 54 tightly. Then, the inlet pipe 5 is arranged so that the spiral groove 53 and the refrigerant flow passage 52 are parallel to each other.
5, 56 and an outlet pipe 57, which will be described later, and the inlet pipe 56 has a valve opening degree controlled based on detection signals such as the outside temperature and the outlet water temperature of the user-side heat exchanger 4. A flow rate regulating valve 58 such as an electric expansion valve is provided. 6 and 7 are inlet pipes 5 from the unused and used side heat exchangers 3 and 4 to the pressure reducing device 5, respectively.
The first and second check valves 8 and 9 allow flow only to the use side and non-use side heat exchangers 4 and 3, and the third check valves 8 and 9 allow flow from the outlet pipe 57 of the pressure reducing device 5 only to the use side and non-use side heat exchangers 4 and 3. The fourth check valve 10 is the pressure reducing device 5
The pressure reducing device 5 is a capillary tube that is connected in parallel with the inlet pipe 55 of the air conditioner and the inlet of the user-side heat exchanger 4 during cooling. Further, solid line arrows in the figure indicate the heating cycle, and dotted line arrows indicate the flow direction of the refrigerant during the defroid cycle.

First, during the heating cycle, the user-side heat exchanger 4 acts as a condenser to heat water and condense and liquefy the refrigerant. The liquid refrigerant passes through the second check valve 7, flows through the spiral groove 53 of the pressure reducing device 5, is depressurized, passes through the fourth check valve 9, reaches the non-use side heat exchanger 3, and evaporates there. Return to compressor 1.
On the other hand, a part of the liquid refrigerant from the user-side heat exchanger 4 is reduced in pressure by the flow rate adjustment valve 58, evaporates in the refrigerant flow path 52, cools the refrigerant flowing in the spiral groove 53, and changes its fluid resistance. By doing so, the flow rate of refrigerant flowing through the spiral groove 53 is appropriately controlled. At this time, a voltage calculated based on the outside air temperature and water temperature detection signals is applied to the flow rate regulating valve 58 to determine the valve opening degree. This is because the heating capacity is determined by the outside air temperature and water temperature. Next, during the defrost operation to melt the frost attached to the heat exchanger 3 on the non-use side, the cycle is reverse to the heating cycle, so the high temperature discharge gas from the compressor 1 is transferred to the non-use side during the heating operation. It goes to the heat exchanger 3, where it radiates heat and condenses to liquefy, thereby melting the adhered frost. This liquid refrigerant flows through the first check valve 6
A part of the liquid refrigerant passes through the pressure reducing device 5 and the third check valve 8 in the same way as during heating operation, and the remaining liquid refrigerant passes through the capillary tube 10 and enters the user-side heat exchanger 4 during heating operation. It evaporates and returns to the compressor 1.

By the way, during the defrost operation, since frost is attached to the non-use side heat exchanger 3, the condensing temperature is kept lower than the temperature during normal heating operation, and therefore the high pressure side pressure is also lowered. Therefore, the pressure difference between high pressure and low pressure becomes small, and the pressure reducing device 5 and capillary tube 1 exhibit flow characteristics proportional to this pressure difference.
There was a drawback that the flow rate of refrigerant flowing through the 0 was reduced, the defrosting ability was reduced, and the defrosting time took a long time.

This invention was made to eliminate the above-mentioned drawbacks, and during defrost operation, the flow rate adjustment valve 5
It is an object of the present invention to provide an air conditioner that can ensure a refrigerant flow rate during a defrost operation and quickly end the defrost operation by forcibly opening the valve opening of No. 8.

An embodiment of this invention shown in FIG. 3 will be described below. 3 differs from FIG. 1 in that a valve control device 60 is provided that forcibly opens the flow rate regulating valve 58 by a predetermined amount during defrost operation.

During heating operation, the user-side heat exchanger 4 acts as a condenser to heat water and condense and liquefy the refrigerant, as in the conventional cycle. The liquid refrigerant is then
The spiral groove 53 of the pressure reducing device 5 passes through the check valve 7 of
The air is depressurized, passes through the fourth check valve 9, reaches the non-use side heat exchanger 3, evaporates there, and returns to the compressor 1. On the other hand, a part of the liquid refrigerant from the user-side heat exchanger 4 is reduced in pressure by the flow rate adjustment valve 58, evaporates in the refrigerant flow path 52, cools the refrigerant flowing in the spiral groove 53, and changes its fluid resistance. By doing so, the flow rate of the refrigerant flowing through the spiral groove 53 is appropriately controlled. At this time, a voltage calculated based on the outside air temperature and water temperature detection signals is applied to the flow rate adjustment valve 58 to adjust the opening degree of the valve. This is because the heating capacity is determined by the outside air temperature and water temperature. Next, during the defrost operation to melt the frost attached to the heat exchanger 3 on the non-use side, the cycle is reverse to the heating cycle, so the high temperature discharge gas from the compressor 1 is transferred to the non-use side during the heating operation. Go to heat exchanger 3,
Here, the frost is melted by dissipating heat and condensing it into liquid. This liquid refrigerant passes through the first check valve 6, a part of which flows through the pressure reducing device 5 in the same manner as in the heating operation, and passes through the third check valve 8, and the remaining liquid refrigerant passes through the capillary tube 10. It reaches the user-side heat exchanger 4 during heating operation, evaporates, and returns to the compressor 1. At this time, regardless of the outside air temperature and water temperature, the flow rate regulating valve 5
Since the valve control device 60 forcibly opens the flow rate adjustment valve 58 by a predetermined amount, for example, fully opens the flow rate adjustment valve 58, a sufficient amount of refrigerant flows through the flow rate adjustment valve 58, and In order to sufficiently cool the refrigerant that evaporates within the spiral grooves 53 and flows within the spiral grooves 53, the refrigerant that is partially gasified within the spiral grooves 53 is liquefied and its flow path resistance is reduced. For this reason,
During defrost operation, the condensing pressure decreases and the pressure difference between the high and low pressures before and after the pressure reducing device 5 and the capillary tube 10 is small, but as mentioned above, the pressure reducing device 5
Since the flow path resistance is reduced, a sufficient flow rate of refrigerant can be ensured, and the defrost operation can be completed quickly.

In the above embodiment, an example was described in which the opening degree of the flow rate adjustment valve 58 is fully opened during defrosting, but this opening degree is determined by the capacity of the valve and the capacity of the device, and is always fully open. For example, it may be forced to open at 4/5 or 2/3.

In addition, although water was selected as an example of the heat medium flowing through the heat exchanger 4 on the user side, it is not limited to water, and air may be used, and the refrigerant circuit shown in Fig. 1 may also include an accumulator, a liquid receiver, etc. Needless to say, it's a good thing.

As described above, according to this invention, by forcibly opening the flow rate regulating valve during defrost operation of heating, a sufficient flow rate of refrigerant flowing through the pressure reducing device can be ensured, and the defrost operation can be completed quickly. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional air conditioner, FIG. 2 is a block diagram showing an example of the pressure reducing device shown in FIG. 1, and FIG. 3 is a block diagram showing an embodiment of this invention. In the figure, 1 is a compressor, 2 is a four-way switching valve, and 3 is a compressor.
4 is a non-use side heat exchanger, 4 is a use side heat exchanger, 5 is a pressure reducing device, 58 is a flow rate adjustment valve, 6 to 9 are first to fourth check valves, and 60 is a valve control device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A compressor, a four-way switching valve, a user-side heat exchanger,
A part of the liquid refrigerant is used to circulate through the pressure reduction section by a non-use side heat exchanger and a flow rate adjustment valve whose opening degree is controlled according to the outside air temperature and the outlet side heat medium temperature of the use side heat exchanger. In an air conditioner equipped with a refrigeration cycle configured by connecting a pressure reducing device that adjusts the cooling amount of the refrigerant to control the flow rate of the refrigerant flowing through the pressure reducing part, and a check valve, etc., when the heating cycle is operated. An air conditioner comprising a valve control device that forcibly opens the flow rate regulating valve by a predetermined amount during winter defrost operation in a reverse cycle.