JPH06281270A - Air conditioner - Google Patents

Abstract

PURPOSE:To maintain a required amount of oil constantly in a compressor by connecting an oil separator in a refrigerant feed line between a compressor and a four-way valve to the compressor through two oil circuits and providing an oil-bypass valve in one of the oil circuits. CONSTITUTION:High-temperature, high-pressure gas from a comppressor 1 in the quantities in excess of the required quantities is returned to an accumulator 7 after a hot-gas bypass valve 12 in a line interconnecting the downstream side of an oil separator 9 and the accumulator 7 is actuated. At this moment, oil having been separated from gas at the separator 9 flows into an oil cooler 11 through a filter and is returned to the compressor 1, wherein two oil return circuits 13, 14 of capillary tube are utilized. An oil bypass valve 15 which is opened and closed by indoor temperature is provided in the circuit 14 and when return oil in the quantities larger than usually required is needed, the oil bypass valve 15 is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an energy-saving type air conditioner, and more particularly to a gas heat pump type air conditioner.

[0002]

2. Description of the Related Art Generally, air-conditioning systems of the type in which a compressor is driven by an electric motor are in widespread use, but this type of air-conditioning system has the drawback of high electricity charges and high maintenance costs. To eliminate this drawback, city gas, LP
A type in which a compressor is driven by a gas engine that uses gas is becoming widespread instead of a type that uses an electric motor. The method using a gas engine has an advantage that exhaust heat of the engine can be used and speed heating is possible.

Both the type using an electric motor and the type using a gas engine have the same basic cycle of heating and cooling. In the cooling cycle, the high-temperature high-pressure gas from the compressor is sent to the outdoor unit heat exchanger via the four-way switching valve, and the high-temperature high-pressure gas is condensed into a high-temperature high-pressure liquid. The high temperature and high pressure liquid is
The expansion valve forms a low-temperature low-pressure gas-liquid two-phase into the indoor unit heat exchanger, evaporates into a low-temperature low-pressure gas, performs indoor cooling, and returns the low-temperature low-pressure gas to the compressor. Cooling is performed by repeating this cycle. The heating cycle is
The high-temperature high-pressure gas from the compressor is sent to the indoor unit heat exchanger via a four-way switching valve, and the high-temperature high-pressure gas is condensed to form a high-temperature high-pressure liquid for indoor heating. The high-temperature high-pressure liquid enters the outdoor unit heat exchanger as a low-temperature low-pressure gas-liquid two-phase by the expansion valve, takes heat from the outside and evaporates to become a low-temperature low-pressure gas and returns to the compressor. Heating is performed by repeating this cycle.

[0004]

In such an air conditioning system, the oil in the refrigerant discharged from the compressor is separated by the oil separator and returned to the compressor. In this case, a capillary tube is used, but the amount of returned oil changes depending on the pressure difference, temperature, and oil viscosity. For example, in the case of low temperature cooling and low temperature heating, there is little oil return, and during high temperature cooling the oil returns too much. Therefore, the present invention allows for the return of the required amount of oil under all operating conditions.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an oil separator in a refrigerant supply line between a compressor and a four-way switching valve via at least two oil circuits. The oil bypass valve is connected to one of the oil circuits.

[0006]

[Function] The oil bypass valve is opened and closed according to the room temperature during heating and the outside air temperature during cooling to secure the required amount of oil for the compressor under any operating condition.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic principle of an air conditioning cycle will be described with reference to FIG. The high-temperature high-pressure gas from the compressor 1 during heating enters the indoor unit heat exchanger 2 and outputs heat to the outside, that is, performs indoor heating. Then, the supercooling heat exchange section 4 is entered. Here, the high-temperature high-pressure liquid enters the expansion valve 5, transforms into the low-temperature low-pressure liquid, enters the outdoor unit heat exchanger 6, evaporates by the heat from the outside, becomes a low-temperature low-pressure gas, and returns to the compressor 1.
During cooling, the cycle opposite to the above is performed, and the indoor unit heat exchanger 2 absorbs heat in the room to transform the low temperature low pressure liquid into low temperature low pressure gas.

FIG. 2 shows the relationship between the cycle pressure during heating and the enthalpy. As is clear from the figure,
The expansion mechanism 5 makes the gas-liquid two phases and then the liquid phase, and enters the expansion valve 5. Refrigerant can be saved by using gas-liquid two-phase by the throttling mechanism 3.

FIG. 3 shows a detailed embodiment. The cycle will be described by taking an example of heating. The high-temperature and high-pressure gas from the compressor 1 connected to the accumulator 7 via the filter 8 is supplied to the oil separator 9 and the four-way switching valve 1.
0 to the indoor unit heat exchanger 2. The indoor unit heat exchanger 2 condenses the refrigerant into a high-temperature high-pressure liquid while heating the room. However, due to the pressure drop by the throttling mechanism 3, the gas-liquid two-phase is formed, and the gas-liquid two-phase is introduced into the supercooling heat exchange section 4 to make it the liquid phase. This liquid phase becomes low-temperature low-pressure liquid by the expansion valve 5 and enters the outdoor unit heat exchanger 6. The outdoor unit heat exchanger 6 evaporates the low-temperature low-pressure liquid by external heat to form a low-temperature low-pressure gas. The low-temperature low-pressure gas returns to the accumulator 7 via the four-way switching valve 10 and the oil cooler 11.

Unnecessarily high temperature and high pressure gas from the compressor 1 is connected to the hot gas bypass valve 1 in the line connecting the downstream side of the oil separator 9 and the accumulator 7.
2 is operated and returned to the accumulator 7.

The oil separated from the gas by the oil separator 9 flows into the oil cooler 11 through the filter. The oil in the oil cooler 11 having a normal heat exchanger configuration raises the temperature of the low-temperature low-pressure gas from the outdoor unit heat exchanger 6, lowers its own temperature, and returns to the compressor 1. At this time, the two oil return circuits 1 of the capillary tube
3 and 14 are used, and one circuit 14 is provided with an oil bypass valve 15 that opens and closes depending on the indoor temperature (when heating) or the outside temperature (when cooling), and it is necessary to return more oil than the normal oil return amount. The oil bypass valve 15 is opened.

The downstream side of the supercooling heat exchange section 4 is connected to the accumulator 7 via the liquid injector syn valve 16.
It makes it possible to return part of the liquid phase to the accumulator 7.

The temperature sensing cylinder 17 on the downstream side of the oil cooler 11 is connected to the expansion valve 5, and the opening of the expansion valve 5 is adjusted by the temperature signal from the temperature sensing cylinder 17. For example, when the temperature signal from the temperature sensing cylinder 17 rises, the opening degree of the expansion valve 5 is increased.

Although the refrigerant cycle during heating has been described, during cooling, the four-way switching valve 10 is switched, the high temperature high pressure gas from the compressor 1 is sent to the outdoor unit heat exchanger 6, and this is condensed into a high temperature high pressure liquid. . The refrigerant then returns to the accumulator 7 via the expansion valve 5 and the indoor unit heat exchanger 2 as an evaporator. These cycles are the reverse of the flow of the refrigerant during heating, and detailed description thereof will be omitted. During cooling, the refrigerant bypasses the throttle mechanism 3.

[0015]

[Effect] Since the oil bypass valve of the solenoid valve can be opened / closed only in the operation region where the amount of oil returned to the compressor is small, the required amount of oil to the compressor can be secured at all times.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle of an air conditioner of the present invention.

FIG. 2 is a graph showing the relationship between enthalpy and pressure.

FIG. 3 is a diagram showing details of an example of the present invention.

[Explanation of symbols]

 1 Compressor 2, 6 Heat Exchanger 3 Throttle Mechanism 4 Supercooling Heat Exchange Section 5 Expansion Valve 9 Oil Separator 10 Four-way Switching Valve 11 Oil Cooler 13, 14 Capillary Tube Circuit 15 Bypass Valve

Claims (1)

[Claims] 1. A compressor in an air conditioner in which a refrigerant circuit has a compressor, a four-way switching valve, an indoor unit heat exchanger, a subcooling heat exchange section, an expansion valve, and an outdoor unit heat exchanger. An air conditioner characterized in that an oil separator in a refrigerant supply line between a four-way switching valve and a compressor is connected to a compressor via at least two oil circuits, and one oil circuit is provided with an oil bypass valve.