JPH10111031A - Multi-stage compression heat pump air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure satisfactory heating without the need of a heat source auxiliary apparatus even in the severe cold time by constructing a gas compressor into 2 stages, and cooling discharge gas from a low pressure side gas compressor with a cooling apparatus and feeding it to a high pressure side gas compressor and simultaneously controlling the gas compressor in response to atmospheric temperature. SOLUTION: A gas compressor consists of a high pressure side gas compressor 1 and a low pressure side gas compressor 2, and cooling and heating are changed over by a four-way valve 3. There are further provided three-way valves 4, 5 controlled in response to outdoor atmospheric temperature each of which serves to change over whether both two stages of the gas compressors are operated or whether only any one of the low pressure side gas compressor 2 and the high pressure side gas compressor 1 is operated. An indoor heat exchanger 6 is provided on a refrigerant circuit which serves as an evaporator at the time of cooling to lower indoor temperature with heat absorption while dissipating heat as a condenser at the time of heating. Further, an outdoor heat exchanger 7 is provided which serves as a condenser at the time of cooling while serving as an evaporator at the time of heating to absorb heat from the outdoor atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump air conditioner for cooling or heating a room, and more particularly to a heat pump air conditioner suitable for use in an extremely hot summer or in a severe cold winter.

[0002]

2. Description of the Related Art A heat pump air conditioner for cooling or heating a room is widely used because its operation is simple and clean. In general, it comprises a gas compressor, a four-way switching valve, a heat exchanger, a throttle valve for refrigerant expansion, and the like, and switches between cooling and heating by the four-way switching valve. Heat exchangers are installed indoors and outdoors, respectively. The indoor heat exchanger becomes an evaporator during cooling to absorb heat, and radiates heat as a condenser during heating. The outdoor heat exchanger radiates heat as a condenser during cooling and absorbs heat as an evaporator during heating.
As a heat source for heat radiation or heat absorption outside the room, the air is often used. When this outdoor air is used as a heat source, the air becomes extremely high or very low when the temperature is extremely hot or extremely cold, and the cooling load or the heating load increases. In particular, a decrease in the atmospheric temperature during a severe cold degrades the coefficient of performance of the heat pump, lowers the efficiency and does not serve the function of heating, and also makes the heat pump inoperable. Therefore, when the outdoor air temperature becomes too low during severe cold, other heating appliances are used together.

[0003]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is that a heat pump air conditioner using the outdoor air as a heat source has a very high outdoor air temperature or a very high temperature when the summer is extremely hot or the winter is extremely cold. The function of the air conditioner is sufficiently fulfilled even at low temperatures. Among the two-stage gas compressor and the discharge gas cooling device of the low-pressure gas compressor provided between the two stages, the high-pressure gas compressor and the gas cooling device are used when the cooling load or the heating load is large. The heat pump air conditioner, whose efficiency depends on the outdoor air temperature, is operated by operating the compressor alone or the high-pressure side gas compressor alone in the outside air environment, so as to widen an appropriate use range. That is,
Since three operation cycles can be performed, the efficiency of the season COP can be improved over a wide range.

[0004]

In order to achieve the above-mentioned object, the pressure of the refrigerant gas can be increased by the two-stage gas compressor so that high-efficiency operation can be performed. Is cooled by the cooling device and then sent to the high-pressure gas compressor.Therefore, there is no concern that the discharge gas temperature of the high-pressure gas compressor is too high, the driving power becomes economical, and a different steam temperature for each stage is obtained. There are benefits to be gained. The operation of the two-stage gas compressor is performed by detecting the outdoor air temperature and responding to the case where this temperature is in a range where the coefficient of performance of the heat pump air conditioner is poor. Usually, unlike a general heat pump air conditioner, the operation of only the low-pressure gas compressor alone or the operation of only the high-pressure gas compressor alone is switched. These switchings are performed by the switching device controlled by the detected value of the outdoor air temperature as described above. Rapid cooling can be performed in an extremely hot weather, and the use range of the heat pump air conditioner requires an auxiliary device of any other heat source in severe cold. It can be extended to low temperatures without any delay, and three types of operation cycles can be performed, including switching during normal operation, so that power consumption can be reduced. Naturally, like a general heat pump air conditioner, the operation is controlled depending on the set temperature in the room.

[0005] At the time of heating, it is possible to improve the efficiency by cooling the gas discharged from the low-pressure side gas compressor with the air in the room.

[0006] In cooling the gas discharged from the low-pressure gas compressor, a part of the liquid refrigerant may be injected for cooling.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of connection of each device of the multistage compression heat pump air conditioner of the present invention. The gas compressor has two stages, and includes a high-pressure gas compressor 1 and a low-pressure gas compressor 2. The four-way switching valve 3 is for switching between cooling and heating. The three-way switching valve A4 and the three-way switching valve B5 are controlled depending on the outdoor air temperature, and operate the two-stage gas compressor, operate only the low-pressure gas compressor 2, or operate only the high-pressure gas compressor 1. It is to switch whether to drive. By connecting these devices, it is possible to selectively use cooling and heating by operating the two-stage gas compressor, and further operate only the low-pressure gas compressor 2 or only the high-pressure gas compressor 1 to perform cooling and heating. I can do it. That is, the flow of the six types of high-temperature heat medium and the flow of the low-temperature heat medium can be controlled by a combination of switching methods of the four-way switching valve 3, the three-way switching valve A4, and the three-way switching valve B5.

In FIG. 1, the main components other than the high-temperature side gas compressor 1, the low-temperature side gas compressor 2, the four-way switching valve 3, the three-way switching valve A4 and the three-way switching valve B5 include an indoor heat exchanger 6
In cooling, it becomes an evaporator and absorbs heat to lower the indoor temperature, and during heating it becomes a condenser and releases heat to increase the indoor temperature. The outdoor heat exchanger 7 radiates heat to the outdoor atmosphere as a condenser during cooling, and functions as an evaporator to absorb heat from the outdoor air during heating. The throttle valve A8 functions as an expansion valve during cooling, and the throttle valve B9 functions as an expansion valve during heating. The valve A10 and the valve B11 are switched together with the four-way switching valve 3 when switching between cooling and heating. The cooler 12 cools the gas discharged from the low-pressure gas compressor when the two-stage gas compressor is used. The liquid receiver 13 is also required for the heat pump air conditioner.

[0009] The three-way switching valve A3 and the three-way switching valve B4 are switched by a signal indicating that the outdoor air temperature has reached a predetermined value. This temperature setting can be changed. The automatic temperature adjustment based on the room temperature setting may be the same as a general heat pump air conditioner.

The flow of the high-temperature heat medium and the low-temperature heat medium is controlled by cooling in the summer heat season, heating in the cold winter season, and cooling and heating using a high-pressure gas compressor or a low-pressure gas compressor in normal times. 2 to 7 are shown in FIG. In these figures, the flow of the high-temperature heat medium is indicated by a dotted line, and the flow of the low-temperature heat medium is indicated by a dashed line. That is, FIG. 2 shows cooling using a two-stage gas compressor, and FIG. 3 shows heating using a two-stage gas compressor. FIG. 4 shows cooling using only the low-pressure gas compressor 2, and FIG.
Only use heating. FIG. 6 shows cooling using only the high-pressure gas compressor 1, and FIG. 7 shows heating using the high-pressure gas compressor 1.

[0011]

When the heat source of the heat pump air conditioner is the outdoor air, a two-stage gas compressor is used in order to cope with the high temperature of the outdoor air during the extremely hot summer or the low temperature of the outdoor air during the severe cold winter. This multi-stage heat pump air conditioner enables rapid cooling during intense heat, and enables sufficient heating at low temperatures in outdoor air, which was previously impossible in severe cold, without the need for auxiliary equipment for other heat sources. Further, switching between the three operation cycles of operation using the two-stage gas compressor, operation using only the low-pressure gas compressor, and operation using only the high-pressure gas compressor, which is controlled by the outdoor air temperature, reduces power consumption. Economical

[Brief description of the drawings]

FIG. 1 is a main device connection diagram of a multistage compression heat pump air conditioner of the present invention.

FIG. 2 is a flow chart of a switching valve passage and a heating medium during cooling using a two-stage gas compressor during an extremely hot summer.

FIG. 3 shows a switching valve passage and a flow of a heat medium during heating using a two-stage gas compressor during severe cold winter.

FIG. 4 shows a switching valve passage and a flow of a heating medium during cooling using only a low-pressure side gas compressor in a normal state.

FIG. 5 shows a switching valve passage and a flow of a heating medium during heating using only the low-pressure side gas compressor during normal operation.

FIG. 6 shows a switching valve passage and a flow of a heat medium during cooling using only the normal high-pressure side gas compressor.

FIG. 7 shows the flow of the switching valve passage and the heat medium during cooling using only the normal high-pressure side gas compressor.

[Description of sign]

 Reference Signs List 1 high-pressure gas compressor 2 low-pressure gas compressor 3 four-way switching valve 4 three-way switching valve A 5 three-way switching valve B 6 indoor heat exchanger 7 outdoor heat exchanger 8 throttle valve A 9 throttle valve B 10 valve A 11 valve B 12 cooling Container 13 Liquid receiver

Claims (1)

[Claims] 1. A heat pump air conditioner used for cooling in summer and for heating in winter has a two-stage gas compressor, and cools a low-pressure side discharge gas between the low-pressure gas compressor and the high-pressure gas compressor. A switching device that improves the efficiency of cooling capacity to cope with high or low temperatures when the outdoor air temperature is extremely hot or severely cold, and that air conditioning can be performed by operating only the low-pressure gas compressor alone or by operating only the high-pressure gas compressor alone. A multi-stage compression heat pump air conditioner capable of three operation cycles controlled by outdoor air temperature.