JPS59119158A - Air-cooling heat pump type air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an air conditioner that controls the so-called heating overload state in which high pressure increases due to a rise in indoor or outdoor temperature during heating operation of an air-cooled heat pump type air conditioner. It is related to a harmonizer.

Conventional configuration and its problems In air-cooled heat pump air conditioners that use outdoor air as a heat source, when heat pump heating is performed in early autumn or early spring when the outside air temperature is still high, the amount of heat absorbed by the evaporator is large and the refrigerant The evaporation pressure of the compressor increases, the high pressure of the compressor increases, and an excessive load is placed on the compressor. As shown, a high-pressure switch is installed in the refrigerant circuit a, which is at high pressure only during heating operation, to detect the refrigerant pressure in this refrigerant circuit and switch the electric circuit. To protect the compressor C, the outdoor fan motor d is stopped.

By stopping the outdoor fan motor d, the amount of heat absorbed from the outside air decreases, the evaporation pressure decreases, and the high pressure also decreases. When the high pressure decreases to the return pressure of the high pressure switch, the contact point of the high pressure switch returns to normal, and the outdoor fan motor d, which had been stopped, resumes operation.

However, in this method, when the outdoor fan motor d is stopped due to the operation of the high pressure switch, the evaporation pressure in the outdoor heat exchanger eK drops significantly. Also, if the drop in high pressure is slower than the drop in evaporation pressure, the evaporation pressure will continue to drop by the time the high pressure switch drops to the return pressure, and the outdoor heat exchanger (evaporator) e will continue to be frosted. Then, the temperature detector f provided in the outdoor heat exchanger (evaporator) θ detects the set defrosting temperature and issues a defrosting command.

This waste refrigerant circuit becomes a defrosting cycle, in which the frost in the outdoor heat exchanger e is melted.

In this way, using the defrost cycle for control in a heating overload condition will not only cause a drop in indoor temperature even though it is a heating overload condition, but also cause a large refrigerant pressure difference on both sides of the four-way valve g. Therefore, a loud refrigerant noise is generated as the four-way valve g is switched.

Note that h is a four-way valve changeover switch.Object of the InventionThe present invention is intended to solve such conventional problems.When stopping an outdoor fan motor in order to control heating overload, The purpose of this is to prevent frost from forming on the outdoor heat exchanger (evaporator), which will continue to grow and eventually shift to the defrosting cycle.

Structure of the Invention In order to achieve this object, the present invention provides a high-pressure switch that detects the refrigerant pressure in the refrigerant circuit and switches the electric circuit in a refrigerant circuit that becomes high pressure only during heating operation, and A low-pressure switch is installed in series on the OFF side of the high-pressure switch to switch the electric circuit by detecting the refrigerant pressure in the heat exchanger that serves as an evaporator during heating operation.

In this configuration, when the high pressure increases and the high pressure switch operates to stop the fan motor, if the refrigerant pressure in the outdoor heat exchanger (evaporator) is high, the fan motor remains stopped. The fan motor continues to stop, causing frost on the outdoor heat exchanger (evaporator), and when the evaporation pressure drops below a certain level, the fan motor is started. ) to prevent the system from entering the defrost cycle, which involves switching the four-way valve.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIGS. 3 and 4 showing one embodiment thereof. In the figure, solid line arrows indicate the flow direction of the refrigerant during cooling operation, and dotted line arrows indicate the flow direction of the refrigerant during heating operation.

In Figures 3 and 4, 1 is a compressor, 2 is a four-way valve, and 3
4 is an indoor heat exchanger, 4 is an outdoor heat exchanger, 5 is an outdoor fan motor, 6 is an indoor fan motor, and 7 is installed in the copper pipe 4a of the outdoor heat exchanger 4, This is a low-pressure switch that detects the refrigerant pressure inside the refrigerant, and is operated by the four-way valve changeover switch 9 only during heating operation, like the four-way valve 2. 8 is a defrost temperature switch that detects the defrost start temperature. 10 is the refrigerant circuit 1 which is at high pressure only during heating.
This is a high-pressure switch installed at 1 and detects the refrigerant pressure. The low pressure switch 7 turns off the high pressure switch 10.
It is provided in series with the side 10&.

If high pressure increases due to outside or inside temperature,
The high pressure switch 1o is activated and the outdoor fan motor 6 stops operating. The heat absorption from the outside temperature decreases, the evaporation pressure also decreases, and the outdoor heat exchanger 4 becomes frosted.

By selecting the operating value converted to the temperature of the low-pressure pressure switch 7 to operate at a higher temperature than the operating value of the defrosting temperature switch 8, the low pressure is reduced by the time the heat exchanger temperature falls to the defrosting command temperature. The pressure switch 7 detects the refrigerant pressure in the outdoor heat exchanger 4 and is activated to restart the operation of the outdoor fan motor 5. Therefore, due to heat absorption from the outdoor air, the outdoor heat exchanger 4
Defrost quickly. Further, when the low pressure switch 7 reaches a certain set pressure, the contact point of the low pressure switch 7 returns and the fan motor 6 stops.

In this way, the drop in high pressure pressure is smaller than the drop in evaporation pressure, so the high pressure switch 1o does not return, and the outdoor heat exchanger 4
When the frosting progresses and the defrosting cycle finally begins, in the case of the present invention, the outdoor heat exchanger temperature is lowered from the defrosting command temperature by turning the outdoor fan motor 6 0N-OFF using the low pressure switch 7. It acts to prevent the temperature from entering the defrost cycle without lowering the temperature.

Effects of the Invention The air-cooled heat pump type air conditioner according to the present invention is provided with a high-pressure switch that detects the refrigerant pressure in the refrigerant circuit and switches the electric circuit in the refrigerant circuit that becomes high pressure only during heating operation, and A low-pressure switch is provided in series with the high-pressure switch, which detects the refrigerant pressure in the outdoor heat exchanger that serves as an evaporator during heating operation and switches the electric circuit. If the high pressure switch does not return and the evaporation pressure continues to drop, the low pressure switch detects the refrigerant pressure in the outdoor heat exchanger and turns the outdoor fan motor 0N-OFF to prevent the temperature from dropping to the defrost command temperature. As a result, defrosting during heating overload does not occur.
It has excellent effects such as preventing cold draft during defrosting, and preventing loud refrigerant noise caused by the large difference in refrigerant pressure before and after the four-way valve.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram of a conventional air-cooled heat pump type air conditioner, Fig. 2 is an electrical control circuit diagram of the same air conditioner, and Fig. 3 is an air-cooled heat pump type air conditioner showing an embodiment of the present invention. Fig. 4 is a refrigerant circuit diagram of the air conditioner. 1...Compressor, 4...Outdoor heat exchanger, 6...
...Outdoor fan motor, 7...Low pressure switch, 10...High pressure switch 0 Name of agent Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3

Claims (1)

[Claims] In an air-cooled heat pump refrigeration cycle that uses outdoor air as a heat source, the refrigerant circuit, which is at high pressure only during heating operation, is equipped with a high-pressure switch that detects the refrigerant pressure in the refrigerant circuit and switches the electric circuit. , an air-cooled heat pump type air in which a low-pressure switch that operates only during heating operation and switches the electric circuit by detecting the refrigerant pressure in the outdoor heat exchanger that serves as an evaporator during heating operation is installed in series with the high-pressure switch. Harmonizer,.