JPH01260266A - Air conditioner - Google Patents

Abstract

PURPOSE:To lessen the fall in heating efficiency which is due to defrosting by connecting the connection between the outdoor heat exchanger and a pressure reducing device with the outlet of a compressor by means of a refrigerant circuit having a valve in a setup to open said valve when, during heating, the pressure in the refrigerant circuit on the high pressure side or the temperature of the indoor heat exchanger exceeds their respective prescribed point. CONSTITUTION:When the temperature of the indoor heat exchanger 14 rises above a prescribed point set in a setting means 18 during heating, a solenoid valve 17 opens; then, part of refrigerant which is discharged by a compressor 12, has a high temperature and high pressure, and undergoes a reduction in pressure in the passageway flows into the outdoor heat exchanger 16 after joining a flow of refrigerant which has been liquefied by a heat exchanger 14 and reduced in temperature and pressure by a pressure-reducing valve 15. The refrigerant which is supplied to the heat exchanger 16 through a solenoid valve 17 has a high enthalpy, hence the refrigerant in which the two flows are combined has a higher enthalpy than an ordinary value. Therefore, the heat required by the refrigerant, absorbed through the heat exchanger 16, is reduced and the pressure and temperature of the refrigerant in the heat exchanger 16 become higher than ordinary pressures and temperatures. As a result, the rate at which icing occurs on the surfaces of the heat exchanger 16 slows down, hence a reduction in frequency of the defrosting required.

Description

[Detailed description of the invention] (b) Industrial application field This invention relates to an air conditioner for both cooling and heating.

(B) Prior art In this type of conventional air conditioner, as shown in FIG. Flows into the indoor heat exchanger 4 through the flow path shown by the solid line of the switching valve 3,
It radiates heat into the air supplied by the fan 4a and liquefies it. The liquefied refrigerant is depressurized by the pressure reducing valve 5, becomes low temperature and low pressure, is supplied to the outdoor heat exchanger 6, absorbs heat from the air sent by the fan 6a, vaporizes, and returns to the compression 1fi2 through the four-way switching valve 3 again. It looks like this. During cooling operation, the four-way switching valve 3 is switched to reverse the flow of refrigerant to that during heating operation, and the indoor heat exchanger 4 supplies heat while the outdoor heat exchanger 6 dissipates heat. Also,
The drive device 1 is equipped with an inverter circuit, and controls the capacity of the compressor 2 to adjust the degree of cooling and heating.

(c) Problems to be Solved by the Invention In such conventional air conditioners, it is often seen that the surface temperature of the outdoor heat exchanger 6 drops to below freezing during heating operation, and as a result, the outdoor heat exchanger 6 The water that has condensed on the surface of 6 freezes, creating a so-called frosting state. If the surface of the outdoor heat exchanger 6 is covered with frost, the heat transfer efficiency will drop significantly and the heating capacity of the air conditioner will be insufficient. By operating the outdoor heat exchanger 6, it becomes necessary to melt the frost on the surface of the outdoor heat exchanger 6. Therefore, during the melting process, the air conditioner is turned off for cooling, which causes a problem in that room heating efficiency decreases.

The purpose of this invention is to provide an air conditioner that can reduce the decrease in heating efficiency caused by defrosting work and provide comfortable heating.

(d) Means for Solving the Problems This invention provides a four-way switching valve in which a four-way switching valve is installed in a refrigeration cycle in which a compressor, an indoor heat exchanger, a pressure reducing device, and an outdoor heat exchanger are connected in a ring. In an air conditioner that can perform cooling and heating operations by switching, the connection part between the outdoor heat exchanger and the pressure reducing device and the discharge part of the compressor are connected by a refrigerant path having an on-off valve, and the on-off valve is used during heating. The air conditioner opens when the pressure of the high-pressure side refrigerant path or the temperature of the indoor heat exchanger exceeds a predetermined value.

(e) Operation When the on-off valve is open, the refrigeration cycle operates in the same way as before; however, when the on-off valve is open,
A portion of the high-temperature, high-pressure refrigerant discharged from the compressor is depressurized in the refrigerant path and flows into the outdoor heat exchanger, where it is liquefied in the indoor heat exchanger and depressurized in the decompression device, joining with the refrigerant that has become low-temperature and low-pressure. do.

Since the refrigerant supplied to the outdoor heat exchanger via the on-off valve has a high enthalpy, the combined refrigerant has a higher enthalpy than usual. Therefore, the amount of heat required for the refrigerant to absorb from the outside air through the outdoor heat exchanger is reduced, and the refrigerant pressure and temperature in the outdoor heat exchanger are higher than normal. Therefore, if the on-off valve is opened when the pressure of the high-pressure side refrigerant path during heating or the temperature of the indoor heat exchanger exceeds a predetermined value, the speed of frost formation on the surface of the outdoor heat exchanger will be reduced. As the frequency of defrosting decreases, the heating capacity of the indoor heat exchanger is adjusted.

(f) Examples The present invention will now be described in detail based on examples shown in the drawings. This invention is not limited by this.

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention,
11 is a drive device for the compressor 12, 13 is a four-way switching valve, 14
is an indoor heat exchanger,! 5 is a pressure reducing valve, 16 is an outdoor heat exchanger,
14a is a blower fan for the indoor heat exchanger, 16a is a blower fan for the outdoor heat exchanger, 17 is a solenoid valve (normally closed), TS is a temperature sensor that detects the temperature of the indoor heat exchanger 14, and 18 is a temperature sensor that sets a predetermined temperature. The setting device 19 is a comparator that compares the temperature of the indoor heat exchanger 14 with a predetermined value and opens the valve 17 when the temperature of the indoor heat exchanger 14 rises above the predetermined value.

In such a configuration, during heating operation, the compressor 12
The high-temperature, high-pressure refrigerant discharged from the four-way switching valve 13 passes through the flow path shown by the solid line, flows into the indoor heat exchanger 14, radiates heat to the air supplied by the fan 14a and liquefies, and then passes through the pressure reducing valve 15. The pressure is reduced at a low temperature and low pressure, and the temperature is supplied to the outdoor heat exchanger 16. The refrigerant is vaporized by absorbing heat from the outside air in the outdoor heat exchanger 16, and the four-way switching valve 1
3 and returns to the compressor 12. At this time, the temperature of the indoor heat exchanger 14 detected by the temperature sensor TS is set by the setting device 18.
When the predetermined value is exceeded, the comparator 19 operates the solenoid valve I7 to open it. When the solenoid valve 17 is opened, a part of the high temperature and high pressure refrigerant discharged from the compressor 12 flows into the outdoor heat exchanger 516 while being depressurized in the refrigerant path, is liquefied in the indoor heat exchanger 14, and is liquefied by the pressure reducing valve. It joins with the refrigerant that has been depressurized at step 15 and has a low temperature and low pressure.

Fig. 2 is a pressure (P)-enthalpy (i) diagram, where the solid line shows the P-i diagram in a normal refrigeration cycle when solenoid valve 17 is in the closed state, and the broken line shows the P-i diagram in the normal refrigeration cycle when solenoid valve +7 is in the open state. A Pi diagram in a certain case of a refrigeration cycle is shown. Among the broken lines, the flow indicated by (a) is the refrigerant that is divided through the solenoid valve I7, and the flow (b) is the refrigerant that is not liquefied by the indoor heat exchanger 14.
, the refrigerant flowing into the outdoor heat exchanger 16 via the pressure reducing valve 15. Since the refrigerant separated through the electromagnetic valve 17 has a high enthalpy, the combined refrigerant has a higher enthalpy than usual. Therefore, the amount of heat required for the refrigerant to absorb from the outside air via the outdoor heat exchanger 16 is small, and the refrigerant pressure and temperature inside the outdoor heat exchanger 16 are higher than in the normal case. As a result, the speed of frost formation on the surface of the outdoor heat exchanger 16 slows down, and the frequency of defrosting becomes less frequent.

In this way, when the temperature of the indoor heat exchanger 14 exceeds the set temperature, the solenoid valve 17 bypasses a portion of the refrigerant and supplies it to the outdoor heat exchanger 16, reducing the frequency of defrosting of the outdoor heat exchanger. At the same time, the temperature of the indoor heat exchanger is controlled. Therefore, there is no need to provide an inverter circuit in the drive device 11 to control the capacity of the compressor, and the configuration of the air conditioning device is simplified.

FIG. 3 is a configuration explanatory diagram showing an embodiment of the pond of the present invention, where PS is a pressure switch provided in the refrigerant path between the indoor heat exchanger 14 and the pressure reducing valve 15, and 18a is a setting device for setting a predetermined pressure. , 19a is a comparator that operates the electromagnetic valve 17 to open it when the pressure at the discharge portion of the indoor heat exchanger 142L exceeds a predetermined value, and the other configurations are the same as in FIG.

In such a configuration, during heating, the high-temperature, high-pressure refrigerant discharged from the compressor 12 flows into the indoor heat exchanger 14, radiates heat and liquefies, and then is depressurized by the pressure reducing valve and supplied to the outdoor heat exchanger 16. be done. The higher the capacity of the compressor 12, the higher the pressure detected by the pressure sensor PS, so when the pressure exceeds a predetermined value, the solenoid valve 17 is opened and the refrigerant supplied to the indoor heat exchanger 14 is A portion is bypassed by the solenoid valve 17 and supplied to the outdoor heat exchanger 16 . Therefore, similarly to the above-described embodiment, the speed of frost formation on the surface of the outdoor heat exchanger 16 is slowed down, and the frequency of defrosting is reduced. Furthermore, in this case, the pressure detected by the pressure switch PS is in a proportional relationship with the temperature of the indoor heat exchanger 14, so by controlling the pressure sensor PS to a predetermined value, the temperature of the indoor heat exchanger 14 is also controlled. remains constant. Therefore, there is no need to control the temperature of the indoor heat exchanger 14 by adjusting the capacity of the compression a12 as in the conventional case.

FIG. 4 is a sectional view showing a flow control valve applied to still another embodiment of the present invention, in which 20 is a flow control valve body having a tapered valve seat, 21 is a spherical valve body, and 22 is a valve body. 21 is a spring that presses the valve seat, and it is a spring that presses the valve seat 21 from the flow path 23 to the flow path 2.
4, when the fluid flows in the direction of the arrow, when the pressure difference ΔP exceeds the predetermined value ΔPs, the valve body 21
moves in the direction of the arrow, and as the pressure difference ΔP increases, the flow fi19 of the fluid flowing from the flow path 23 to the flow path 24 increases. Further, the fluid cannot flow from the flow path 24 to the direction 23. When such a flow control valve is used in place of the solenoid valve I7 of the embodiment shown in FIG.
When the pressure ΔP at the discharge part of the compressor 12 exceeds a predetermined value ΔPs, a portion of the refrigerant discharged from the compressor 12 is directly transferred to the outdoor heat exchanger!
6, and the larger the pressure difference ΔP, the greater the flow rate of the refrigerant. Thereby, outdoor heat exchange 6
Since the surface temperature of 16 rises and the speed of frost formation decreases, the frequency of defrosting work becomes less frequent.

(g) Effects of the invention According to this invention, it is possible to set the temperature of the indoor heat exchanger without controlling the capacity of the compressor, and furthermore, the speed of frost formation on the surface of the outdoor heat exchanger is reduced. This reduces the frequency of defrosting work and improves heating efficiency during heating.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, FIG. 2 is a pressure-enthalpy diagram explaining the operation of the embodiment shown in FIG. 1, and FIG. 3 is a diagram showing an embodiment of the pond of this invention. 1 is a diagram corresponding to FIG. 1, FIG. 4 is a sectional view showing a flow control valve constituting another embodiment of the present invention, and FIG. 5 is a graph explaining the operation of the flow control valve shown in FIG. FIG. 6 is a diagram corresponding to FIG. 1 of the conventional example. It... Drive device, 12... Compressor,
13... Four-way switching valve, 14... Indoor heat exchanger, 15... Pressure reducing valve, 16... Outdoor heat exchanger, I7...・7 [Magnetic valve, TS...
・Temperature sensor, 18... Setting device, I9...
...Comparator. Agent Patent Attorney Shinta Nogawa = F,, m%F No. 4
Mouth! f, 52;HhiA Fig. 6

Claims (1)

[Claims] 1. A four-way switching valve is installed in the refrigeration cycle in which the compressor, indoor heat exchanger, pressure reducing device, and outdoor heat exchanger are connected in a ring.
In an air conditioner that can perform cooling and heating operations by switching a four-way switching valve, the connecting part between the outdoor heat exchanger and the pressure reducing device and the discharge part of the compressor are connected by a refrigerant path having an on-off valve. An air conditioner that opens when the pressure of a high-pressure side refrigerant path or the temperature of an indoor heat exchanger exceeds a predetermined value during heating.