JPH0289970A - Heat pump-based indoor cooling and heating apparatus - Google Patents

Abstract

(57) [Abstract] 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 relates to defrosting of a heat pump air-conditioning device driven by an engine or an electric motor used for vehicles and homes.

[Conventional technology]

BACKGROUND ART Some heat pump type air-conditioning devices driven by an engine heat the room using a hot water heater using waste heat from the engine in addition to heating the room using an indoor heat exchanger.

As shown in FIG. 3, this device consists of a compressor 1. Four-way valve that switches the flow direction of refrigerant2.
Outdoor heat exchanger 3. Expansion valve 4. An indoor heat exchanger 5 and an accumulator 6 are sequentially connected to form a refrigerant circuit,
On the other hand, apart from this, a water pump 11. which circulates cooling water for the engine 10. Exhaust heat exchanger12. The hot water heater 4 and the separator 15 constitute a hot water circuit. Note that 13 is a radiator, and I6 and I7 are on-off valves that open and close the hot water flow path.

During heating operation, the outdoor heat exchanger 3 acts as an evaporator and absorbs heat, so when the outside temperature is low, frost forms on the surfaces of the evaporator tubes and fins, but this frost is removed. In order to remove frost, conventionally, a defrosting operation was performed in which the outdoor heat exchanger 3 was operated as a condenser by switching to cooling operation and removing frost by its heat dissipation action.

(Problems to be Solved by the Invention) However, in the defrosting operation described above, since the amount of heat condensed by the outdoor heat exchanger is small, there is a problem that defrosting takes a long time. During the removal 'r1 operation, the indoor heat exchanger absorbs heat and cools the room, so even if the hot water heater heats the room, the cooling is stronger and the room is less likely to be heated. was there.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a heat pump type air-conditioning device that can defrost quickly during the heating season and can sufficiently heat a room. That is.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a compressor driven by an engine or an electric motor, an outdoor heat exchanger, a depressurization device, an indoor heat exchanger, an accumulator, and a switching device that switches the flow direction of refrigerant. , in a heat pump type air-conditioning device equipped with a refrigeration cycle that performs indoor cooling and heating by switching the switching device, a bypass circuit that bypasses the pressure reduction device, a bypass valve that opens and closes this bypass circuit, and a bypass valve that opens and closes the bypass circuit; A variable rotation speed machine that varies the rotation speed of an engine or an electric motor, a frost sensor that detects the occurrence of frost in the outdoor heat exchanger, and a temperature sensor that detects the temperature of the refrigerant flowing to the indoor heat exchanger. In preparation, if the frost sensor detects frost during heating operation of the refrigeration cycle, the rotation speed variable machine increases the rotation speed of the engine or electric motor, and then the temperature sensor reaches a set value. In this case, a technical means is used to open the bypass valve to bypass the decompression device and send refrigerant from the indoor heat exchanger to the outdoor heat exchanger.

[Effect]

According to the above means, when frost occurs on the outdoor heat exchanger during heating operation, the rotation speed of the engine or electric motor is increased during heating operation to raise the temperature of the refrigerant in the indoor heat exchanger and the indoor heat exchanger itself. A heat storage operation is performed to raise the temperature, and the liquid refrigerant in the indoor heat exchanger, which has become high in temperature during this heat storage operation, is sent to the outdoor heat exchanger by bypassing the depressurization device during the next defrosting operation. The frost that forms on the outdoor heat exchanger is thawed in a short time by the heat of the liquid refrigerant.

In addition, since defrosting operation is performed during heating operation, the indoor heat exchanger acts as a condenser and radiates heat, and also radiates the heat stored during double heat storage operation, so the room remains indoors even during defrosting operation. It's warm.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 is a refrigerant circuit diagram together with a hot water circuit showing an embodiment of the engine-driven heat pump air-conditioning apparatus of the present invention.

In the figure, reference numeral 1 denotes a compressor driven and rotated by an auxiliary engine 10, and the refrigerant flows from the high-pressure side of the compressor I through an electromagnetic four-way valve 2 that switches the direction of flow to an outdoor heat exchanger 3 having a blower fan 3a. Connected. This outdoor heat exchanger 3 is
The indoor heat exchanger 5 containing the blower fan 5a is passed through the decompression device 4, which is composed of an expansion valve and the like that adiabatically expands the refrigerant from the outdoor heat exchanger 3, which functions as a condenser in cooling operation and as an evaporator in heating operation. connected to. This indoor heat exchanger 5 functions as an evaporator in cooling operation and as a condenser in heating operation. Note that this indoor heat exchanger 5 is connected to outdoor heat exchanger 3 by bypassing depressurization device 4. A bypass circuit 20 is provided, and a bypass valve 7 for opening and closing the bypass circuit 20 is provided. The indoor heat exchanger 5 is connected to the low pressure side of the compressor 1 via the four-way valve 2 and the accumulator 6, which separates the refrigerant into gas and liquid, thereby forming a refrigerant circuit.

On the other hand, 11 is a water pump that circulates cooling water to cool the auxiliary engine 10. The water pump 11 is connected to the exhaust heat exchanger 12 in which the cooling water is heat-exchanged by the engine waste heat after passing through the auxiliary engine 10. Branched from the exchanger 12, one side is connected to the radiator 13 via the on-off valve 16, the other side is connected to the hot water heater 14 disposed indoors via the on-off valve 17, and from the radiator 13 and hot water heater 14 to the separator 15. After merging, the end thereof is connected to the water pump 11 to form a hot water circuit.

A frost sensor 8 is attached to the surface of the evaporator tube of the outdoor heat exchanger 3 to indirectly detect the formation and disappearance of frost based on the surface temperature. A temperature sensor 9 is attached inside or on the surface of the refrigerant pipe to directly or indirectly detect the temperature of the refrigerant flowing through the pipe.

Further, the auxiliary engine 10 is attached with a variable rotation speed machine 18, which is made of, for example, a step motor, and which varies the rotation speed of the auxiliary engine 10.

As will be described later, when the frost sensor 8 detects the occurrence of frost, the variable speed machine 18 operates to control the auxiliary engine 1.
When increasing the rotation speed of 0 and detecting the disappearance of the following, the rotation speed variable machine 1 operates to return the auxiliary engine 10 to the normal rotation speed and close the bypass valve 7, and When the temperature sensor 9 detects a temperature higher than a set value, the bypass valve 7 is opened.

Here, in the case of cooling operation, the flow of refrigerant in the refrigerant circuit is from the compressor 1 through the passage ports 2a and 2b of the four-way valve 2 to the outdoor heat exchanger 3. The flow flows from the decompression device 4 to the indoor heat exchanger 5, passes through the flow passage ports 2d and 2c of the four-way valve 2 again, passes through the accumulator 6, and returns to the compression II.On the other hand, in the case of heating operation, the flow from the compressor 1 to the Flow passage ports 2a and 2 of valve 2
d through the indoor heat exchanger5. Decompression device4. It flows into the outdoor heat exchanger 3 in the opposite direction to that in the cooling operation, passes through the flow passage ports 2b and 20 of the four-way valve 2 again, passes through the accumulator 6, and returns to the compressor 1 (indicated by the arrow in the figure).

In addition, in the case of cooling operation, the flow of hot water in the hot water circuit is from the water pump 11 to the exhaust heat exchanger! 2, passes through the radiator 13, enters the separator 15, and returns to the water pump 11 (indicated by → in the figure).
In the case of heating operation, the flow is from the water pump 11 through the exhaust heat exchanger 12, through the hot water heater 14, into the separator 15, and back to the water pump 11 (indicated by → in the figure).

Next, the operation of the apparatus in the above embodiment will be explained based on FIG.

In heating operation, the flow of refrigerant is opposite to that in cooling operation, as described above, and the refrigerant is compressed by compressor l;
The gas refrigerant is sent to the indoor heat exchanger 5 through the flow path ports 2a and 2d of the four-way valve 2, and when the refrigerant is condensed and liquefied in the indoor heat exchanger 5, it radiates heat and warms the room. The refrigerant condensed and liquefied in the indoor heat exchanger 5 undergoes adiabatic expansion in the decompression device 4, becomes a mist of refrigerant, and is sent to the outdoor heat exchanger 3, where it absorbs heat as it evaporates. Therefore, when the outdoor temperature is low, moisture in the air freezes due to endothermic action, and frost is generated mainly on the surface of the evaporation tube of the outdoor heat exchanger 3.

In this case, the occurrence of frost is detected by the frost sensor 8 attached to the surface of the evaporator tube of the outdoor heat exchanger 3, and an instruction is issued from a control circuit (not shown) based on the detection signal, and the frost sensor 8 attached to the auxiliary engine 10 The variable rotation speed machine is operated to increase the rotation speed of the auxiliary engine 10 to nearly the maximum rotation speed of the heat pump system.

Therefore, a heat storage operation is performed in which the discharge pressure of the refrigerant increases as the rotational speed of the compressor 1 increases, and thereby the temperature of the refrigerant flowing through the indoor heat exchanger 5 also increases.

At the same time, the exhaust heat amount of the auxiliary engine 10 increases due to the increase in the auxiliary engine 100 rotation speed, so the exhaust heat exchanger 1
2, the amount of heat exchange increases, and the engine cooling water becomes warmer.
This high-temperature hot water is sent to the hot water heater 14 to warm the room.

Here, when the temperature detected by the temperature sensor 9 attached to the refrigerant pipe of the indoor heat exchanger 5 and detecting the refrigerant temperature exceeds a set value, a control circuit (not shown) issues an instruction to open the bypass valve 7. Since the high-temperature liquid refrigerant from the indoor heat exchanger 5 is sent to the outdoor heat exchanger 3 bypassing the depressurization device 4, the frost generated in the outdoor heat exchanger 3 is removed for a short time by the heat of this high-temperature refrigerant. It is thawed and defrosted. The liquid refrigerant that has passed through the outdoor heat exchanger 5 passes through the flow path ports 2b and 2C of the four-way valve 2 again, is separated into gas and liquid by the accumulator 6, and the gas refrigerant is led out and returned to the compressor 1.

Note that during the defrosting operation described above, the blower fan 3a of the outdoor heat exchanger 3 is stopped in order to increase the defrosting efficiency by one. Furthermore, in addition to the heat dissipation from the indoor heat exchanger 5, the heat dissipation from the high-temperature hot water heater 14 allows the room to be sufficiently warmed even during the defrosting operation.

When the frost sensor 8 attached to the outdoor heat exchanger 3 detects defrosting on the surface of the evaporator tube, an instruction is issued from the control circuit (not shown) and the variable speed machine 18 is activated to keep the auxiliary engine 1o at a steady state. The rotation speed is returned to , the blower fan 3a starts operating, and at the same time, the bypass valve 7 closes and the refrigerant passes through the pressure reduction device 4 and becomes a normal flow of refrigerant, ending the defrosting operation and returning to the original heating operation.

FIG. 2 is an operation flowchart that shows the above-mentioned operations together. To explain the operation flow in a diagram, heating operation is performed in step 101, and the presence or absence of frost generation is determined in step 102. If yes, step 103 The engine speed is increased to perform heat storage operation, and if there is no temperature, the heating operation in step 101 is continued.Next, the refrigerant temperature is determined in step 104, and if it is higher than the set value, the bypass valve is opened in step 105. If the temperature is below the set value, the heat storage operation in step 103 is continued. After that, in step 106, it is determined whether or not defrosting is required, and if it is, step 1
At step 07, the bypass valve is closed and the engine speed is returned to normal to end the defrosting operation, and if there is no defrosting operation, step 105
Continue defrosting operation.

Next, in this embodiment, the end of the heat storage operation of the indoor heat exchanger 5 was determined based on the temperature of the refrigerant flowing into the indoor heat exchanger 5. It may also be determined by the discharge pressure of the refrigerant.

In this example, heat storage operation and defrosting operation were performed without changing the air volume of the blower fan 5a of the indoor heat exchanger 5, but by reducing the air volume to an appropriate level, the amount of heat storage can be increased and removed. Frost time can be shortened.

Further, in this embodiment, the electromagnetic four-way valve 2 is used to switch the refrigerant flow path, but a plurality of electromagnetic on-off valves may be used instead of the electromagnetic four-way valve 2. Any switching device that can switch to the flow path may be used.

Furthermore, in this embodiment, the compressor l is driven by the auxiliary engine 1.
Although the description has been made regarding the operation performed by an electric motor, it is of course applicable to operations performed using an electric motor. However, when using an electric motor, there is no need to use a hot water circuit using engine waste heat.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

(b) Frost that forms on the outdoor heat exchanger is thawed in a short time by the high-temperature liquid refrigerant that is sent from the indoor heat exchanger to the outdoor heat exchanger bypassing the depressurization device, so defrosting is completed quickly. do.

(b) Since defrosting is performed during heating operation, the room is heated even during defrosting operation due to heat radiation from the indoor heat exchanger.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram including a hot water circuit showing an embodiment of the heat pump air-conditioning device of the present invention, Fig. 2 is an operation flowchart of the same device, and Fig. 3 is a refrigerant circuit diagram including a hot water circuit of a conventional device. It is a circuit diagram. ■...Compressor, 2...Switching device, 3...Outdoor heat exchanger 4...Decompression device, 5...Indoor heat exchanger, 6...
・Accumulator, 7... Bypass pulp, 8...
Frost sensor, 9...Temperature sensor, 10...Auxiliary engine, 1st...Variable rotation speed machine, 20...Bypass circuit.

Claims (1)

[Scope of Claims] It has a compressor driven by an engine or an electric motor, an outdoor heat exchanger, a pressure reducing device, an indoor heat exchanger, an accumulator, and a switching device that switches the flow direction of the refrigerant. In a heat pump type air-conditioning device equipped with a refrigeration cycle that cools and heats a room, the device includes a bypass circuit that bypasses the pressure reduction device, a bypass valve that opens and closes this bypass circuit, and a rotation speed of the engine or electric motor. a variable rotation speed machine that varies the rotation speed; a frost sensor that detects the occurrence of frost in the outdoor heat exchanger; and a temperature sensor that detects the temperature of the refrigerant flowing in the indoor heat exchanger; When the frost sensor detects frost during operation, the engine or electric motor is operated by increasing the rotation speed by the variable rotation speed machine, and then, when the temperature sensor reaches a set value, the bypass valve is opened. 1. A heat pump type air-conditioning and heating apparatus, characterized in that the refrigerant is sent from the indoor heat exchanger to the outdoor heat exchanger by bypassing the pressure reducing device.