JPH04225758A - Heat-pump type air-conditioner - Google Patents

Abstract

PURPOSE:To maintain the heating capacity of an air-conditioner for preventing the heating performance from falling during cold whether period by a method wherein in heating operation, refrigerant absorbs heat from the outside air through an outdoor heat exchanger or from heating medium through a heater, and a refrigerant is adequately selected corresponding to the outside air temperature. CONSTITUTION:A heater 21 is installed between an outdoor heat exchanger 3 and a restriction device 7 and supplied with hot-water through a hot-water valve 22 so that the refrigerant exchanges heat with the heating medium and heated. One end of a bypass pipe 23 is connected to a pipe between the outdoor heat exchanger 3 and the heater 21, and the other end to the suction side of a compressor 1, for example, to an inlet pipe of an accumulator 10. A first on-off valve 24 is provided on the bypass pipe 23, and a second on-off valve 26 on a pipe between the outdoor heat exchanger 3 and a divergence point 25 of the bypass pipe 23. Those on-off vales 24 and 26 are opened and closed to shift the flow direction of the refrigerant. A pressure sensor 27 is installed on the inlet pipe of the accumulator 10, and the on-off valve 24 is controlled in on-off manner based on signals from the sensor 27.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner.

0002

[Prior Art] Fig. 2 is a system diagram showing an example of a conventional heat pump type air conditioner.
It is composed of an indoor heat exchanger 8, an indoor fan 9, etc.

During cooling operation, the four-way switching valve 2 is switched as shown by the solid line. Then, the high temperature and high pressure refrigerant gas discharged from the compressor 1 passes through the four-way switching valve 2 as shown by the solid arrow.
It then enters the outdoor heat exchanger 3, where it is condensed and liquefied by radiating heat to the outside air sent by the outdoor fan 4. Next, most of this refrigerant liquid flows to the other side of the parallel pipe due to the flow resistance caused by the heating throttle device 5 installed in one of the parallel pipes, passes through the check valve 6, and then enters the throttle device 7. After being compressed and reduced in pressure, it flows into the indoor heat exchanger 8. And the refrigerant is this indoor heat exchanger 8
In the process of flowing through the air, the indoor air is cooled by exchanging heat with the indoor air sent by the indoor fan 9, and is evaporated into refrigerant gas, which enters the accumulator 10 after passing through the four-way switching valve 2. Here, the refrigerant liquid is separated from the refrigerant gas, and then sucked into the compressor 1 where it is again compressed.

During heating operation, the four-way switching valve 2 is switched as shown by the broken line. Then, the refrigerant gas discharged from the compressor 1 flows into the indoor heat exchanger 8 through the four-way switching valve 2 as shown by the broken line arrow, and in the process of flowing through the indoor heat exchanger 8, it is sent to the indoor air by the indoor fan 9. By exchanging heat with the air, it heats the indoor air and condenses itself into a liquid. Next, this refrigerant liquid is reduced in pressure by being throttled in the process of flowing through the expansion device 7 and the heating expansion device 5, and then enters the outdoor heat exchanger 3, where it absorbs heat from the outside air sent by the outdoor fan 4. vaporized. This refrigerant gas then passes through the four-way switching valve 2 and then enters the accumulator 10, where the refrigerant liquid is separated from the refrigerant gas, and is then sucked into the compressor 1 where it is compressed again.

[0005]

[Problems to be Solved by the Invention] The conventional heat pump type air conditioner described above has the following problems to be solved.

That is, in the conventional heat pump type air conditioner, the heat absorption source of the refrigerant during heating operation is due to the outside air, so the heating capacity decreases as the outside temperature decreases. As a countermeasure to this problem, some air conditioners supplement the heating capacity by heating the indoor air with an auxiliary heater when the outside temperature is low. The purpose of the present invention is to provide a heat pump type air conditioner that maintains heating capacity by using a heat source such as combustion gas.

[0007]

[Means for Solving the Problems] The present invention provides a means for solving the above problems, in which a compressor, an outdoor heat exchanger, a throttle device, and an indoor heat exchanger are connected to form a refrigerant circuit, and outside air is removed during heating operation. In the heat pump type air conditioner using the refrigerant as a heat absorption source in the outdoor heat exchanger, a heater is installed between the outdoor heat exchanger and the expansion device and heats the refrigerant by exchanging heat with the heating medium. and a bypass pipe connected at one end between the heater and the outdoor heat exchanger and the other end connected to the suction side of the compressor, and a bypass pipe connected in either direction of the bypass pipe or the outdoor heat exchanger. a switching means for switching the flow of the refrigerant to the refrigerant; and a control means for closing or opening the bypass pipe in accordance with a rise or fall in pressure within the outdoor heat exchanger during heating operation in which the heating medium is used as a heat absorption source of the refrigerant. An object of the present invention is to provide a heat pump type air conditioner characterized by comprising the following.

[0008]

[Function] Since the present invention has the above structure, it has the following function.

That is, in the present invention, during heating operation using outside air as a heat absorption source, the flow of the refrigerant is switched to the outdoor heat exchanger by the switching means, and the flow of the heating medium to the heater is stopped. As a result, the refrigerant discharged from the compressor is condensed and liquefied by dissipating heat to the indoor air in the indoor heat exchanger, is depressurized by the throttling device, and then enters the outdoor heat exchanger, where it absorbs heat from the outside air and evaporates. It is vaporized and then returned to the compressor to complete the heating cycle.

On the other hand, during heating operation using the heating medium as a heat absorbing source, the flow of the refrigerant is switched to the bypass pipe by the switching means, and the heating medium is passed to the heater. As a result, the refrigerant discharged from the compressor is condensed and liquefied by dissipating heat to the indoor air in the indoor heat exchanger, then reduced in pressure by the expansion device, and then enters the heater, where it absorbs heat from the heating medium and evaporates. The air then returns to the compressor via a bypass pipe to complete the heating cycle.

[0011] Also, during this heating operation, refrigerant liquid is stored in the outdoor heat exchanger, and when the pressure inside this vessel rises and exceeds a predetermined pressure, the bypass line is closed. As a result, refrigerant is drawn into the compressor from inside the outdoor heat exchanger and recovered into the heating circuit. On the other hand, when the refrigerant is no longer present in the outdoor heat exchanger, the pressure inside the outdoor heat exchanger drops, and when the pressure falls below a predetermined pressure, the bypass pipe is opened and heating operation is restarted.

0012

[Embodiment] An embodiment of the present invention will be explained with reference to FIG. Note that the same reference numerals are given to the same constituent members as in the conventional example, and the explanation thereof will be omitted.

FIG. 1 is a system diagram of a heat pump type air conditioner according to this embodiment. In the figure, a heater 21 is interposed between the outdoor heat exchanger 3 and the expansion device 7. The heater 21 heats the refrigerant by exchanging heat with a heating medium, and there are various types of heating medium that serve as a heat absorption source for this refrigerant, such as an electric heater and combustion gas, but in this embodiment, hot water is used. The hot water is supplied to the heater 21 via the hot water valve 2.
2.

One end of the bypass pipe 23 is connected between the outdoor heat exchanger 3 and the heater 21, and the other end of the bypass pipe 23 is connected to the suction side of the compressor 1, in this embodiment, the inlet pipe of the accumulator 10. . This bypass pipe 23 has a first on-off valve 24.
, and the branch point 25 between the outdoor heat exchanger 3 and the bypass pipe 23
A second on-off valve 26 is interposed between the two, and the flow direction of the refrigerant is switched by opening and closing the first on-off valve 24 and the second on-off valve 26. That is,
A bypass pipe 23 is provided in parallel to the outdoor heat exchanger 3, and the refrigerant flows in the direction of the outdoor heat exchanger 3 or in the direction of the bypass pipe 23 bypassing the outdoor heat exchanger 3. It is now possible to Here, the second on-off valve 26 is a reversible valve that allows refrigerant to flow in both directions of the valve 26.

The other end 29 of the bypass pipe 23 and the four-way switching valve 2
A check valve 28 is interposed between the
8 allows the flow to flow only toward the suction side of the compressor 1. Further, a pressure sensor 27 such as a pressure switch that detects the pressure inside the outdoor heat exchanger 3 is attached to the inlet pipe of the accumulator 10, and a first on-off valve 24 is controlled to open and close based on a signal from this pressure sensor 27. It is now possible to do so.

The rest of the structure is similar to the conventional one shown in FIG. 2, and corresponding members are given the same reference numerals as mentioned above.

[0017] However, during heating operation using outside air as a heat absorption source,
In addition to the four-way switching valve 2 being switched as shown by the broken line, the
The on-off valve 24 is closed and the second on-off valve 26 is opened. Further, the hot water valve 22 is in a closed state, and the flow of hot water to the heater 21 is stopped. Then, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way switching valve 2 and enters the indoor heat exchanger 8 as shown by the broken line arrow, where it is condensed and liquefied by heating the indoor air. The pressure is reduced by the throttle device 7, and after passing through the heater 21 and the second on-off valve 26, the pressure is reduced by the heating throttle device 5. Next, this refrigerant enters the outdoor heat exchanger 3, where it absorbs heat from the outside air sent by the outdoor fan 4 and is evaporated and vaporized, and then returns to the compressor 1 via the four-way switching valve 2, check valve 28, and accumulator 10. Complete heating cycle.

On the other hand, during heating operation using hot water as a heat absorption source, the four-way switching valve 2 is switched as shown by the broken line as above, and the first on-off valve 24 is opened and the second on-off valve 26 is closed. . Also, the hot water valve 22 is opened and hot water is supplied to the heater 21.
is passed through. Then, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 passes through the four-way switching valve 2 and enters the indoor heat exchanger 8, as shown by the dashed line, where it is condensed and liquefied by heating the indoor air. The pressure is reduced in the device 7. Next, this refrigerant absorbs heat from the hot water in the process of flowing through the heater 21 and is vaporized, passes through the first on-off valve 24, passes through the bypass pipe 23, passes through the accumulator 10, and returns to the compressor 1 for heating. Complete the cycle.

As described above, during heating operation, the refrigerant can absorb heat from the outside air through the outdoor heat exchanger 3 or from the heating medium through the heater 21, so the heat absorption source of the refrigerant can be appropriately selected depending on the outside air temperature. This ensures the heating capacity of the air conditioner.

[0020] Furthermore, when switching from cooling operation to heating operation using hot water as the heat absorption source of the refrigerant, or during this heating operation, refrigerant liquid may accumulate in the outdoor heat exchanger 3 due to internal leakage of the second on-off valve 26, etc. Then, the pressure inside the outdoor heat exchanger 3 increases. This pressure sensor 27 detects a predetermined pressure (for example, 1.
5 kg/cm2G) or more, pressure sensor 2
Based on the signal No. 7, the first on-off valve 24 is closed and the bypass pipe 23 path is temporarily closed. As a result, refrigerant is drawn into the compressor 1 from inside the outdoor heat exchanger 3 via the four-way switching valve 2, the check valve 28, and the accumulator 10, and is recovered into the heating circuit. When the refrigerant liquid no longer exists in the outdoor heat exchanger 3, the pressure in the outdoor heat exchanger 3 is reduced, and when this pressure becomes less than a predetermined pressure (for example, 0.5 kg/cm2G), the pressure sensor 27 is activated. Based on the signal, the first on-off valve 24 is opened, the bypass pipe 23 is opened, and normal heating operation is resumed.

As described above, this embodiment has the advantage of providing a heat pump type air conditioner whose heating performance does not deteriorate even in cold weather.

[0022]

Effects of the Invention Since the present invention is constructed as described above, it has the following effects.

That is, in the present invention, during heating operation, the refrigerant can absorb heat from the outside air through the outdoor heat exchanger or from the heating medium through the heater. The heating capacity of the air conditioner can be maintained by selecting the appropriate value. This eliminates the drawback of conventional heat pump air conditioners, which degrade heating performance in cold weather.

[0024] Furthermore, during heating operation in which the heating medium is used as a heat absorption source for the refrigerant, the bypass pipes are controlled to close or open as the pressure within the outdoor heat exchanger increases or decreases, so that the air inside the outdoor heat exchanger is controlled to close or open. Since the stored refrigerant is recovered into the heating circuit, it is possible to prevent a shortage of refrigerant in the heating circuit.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a heat pump air conditioner according to an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional heat pump air conditioner.

[Explanation of symbols]

1 Compressor 3 Outdoor heat exchanger 4 Outdoor fan 7 Squeezing device 8 Indoor heat exchanger 21 Heater 23 Bypass pipe 24 First on-off valve 26 Second on-off valve 27 Pressure sensor

Claims (1)

[Claims] [Claim 1] A heat pump in which a compressor, an outdoor heat exchanger, a throttle device, and an indoor heat exchanger are connected to form a refrigerant circuit, and the outside air is used as a heat absorption source for the refrigerant in the outdoor heat exchanger during heating operation. In the type air conditioner, a heater is provided between the outdoor heat exchanger and the expansion device and heats the refrigerant by exchanging heat with the heating medium, and a heater is provided between the heater and the outdoor heat exchanger. a bypass pipe having one end connected to the suction side of the compressor and the other end connected to the suction side of the compressor, a switching means for switching the flow of refrigerant to either the bypass pipe or the outdoor heat exchanger, and a switching means for switching the flow of the refrigerant to either the bypass pipe or the outdoor heat exchanger; A heat pump type, characterized in that it is equipped with a control means for closing or opening the bypass pipe in accordance with a rise or fall in pressure in the outdoor heat exchanger during heating operation using a refrigerant as a heat absorption source. Air conditioner.