JPH0763437A - Engine-operated air-conditioning apparatus - Google Patents

Abstract

PURPOSE:To enable continuing the air-conditioning operation in a stabilized condition even when the load is small. CONSTITUTION:By a refrigerant pipe 10a a four-way valve 3 communicates with a service valve 16 on one hand which sends and receives refrigerant to and from the respective indoor heat exchangers 4 of indoor apparatuses U1 to U5 by means of a refrigerant-side conduit 10c having a usually closed flow- rate control valve 18 and a heat exchanger 19 for the control; by a refrigerant pipe 10b a service valve 17 on the other hand communicates with an outdoor heat exchanger 8; the refrigerant pipes 10a, 10b communicates with each other by connection. A controller 25 controls the valve opening of the flow-rate control valve 18 on the basis of, in cooling, the temperature of the indoor heat exchanger 4 or the pressure of the gaseous refrigerant on the low-pressure side sucked into a compressor 2 and, in heating, the pressure of the gaseous refrigerant on the high-pressure side discharged from the compressor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine driven air conditioner in which a compressor is driven by a gas engine or the like.

[0002]

2. Description of the Related Art As a technique of this kind, for example, Japanese Patent Laid-Open No.
-160281 and Japanese Patent Laid-Open No. 3-177758.

However, in the engine-driven air conditioner disclosed in the above-mentioned Japanese Patent Laid-Open No. 3-160281, when the refrigerant evaporation temperature of the indoor heat exchanger becomes lower than a predetermined temperature during the cooling operation, the refrigerant suction of the compressor. And the refrigerant discharge side are communicated with each other, and the electric valve installed on the refrigerant suction side is opened and closed. Therefore, there is a problem that the room temperature changes stepwise.

On the other hand, in the heating operation of the engine-driven air conditioner disclosed in Japanese Patent Laid-Open No. 3-177758, the condensation temperature of the refrigerant is detected and the opening of the heating control valve is controlled based on this temperature. However, there is a drawback that when the heating load is small, the evaporating pressure is too low and the outdoor heat exchanger may freeze.

[0005]

That is, in the conventional engine-driven air conditioner, there is a problem that stable air conditioning operation cannot be performed when the load is small in both cold / warm air conditioning operation. There was a problem to solve this point.

[0006]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention provides a compressor driven by an engine, a four-way valve, an indoor heat exchanger, a receiver tank, and an outdoor electric valve. , An outdoor heat exchanger, an accumulator, etc. are sequentially connected via a refrigerant pipe, and in an engine-driven air conditioner in which a cooling / heating circuit is formed,

Refrigerant connected to the indoor heat exchanger via the control heat exchanger, which is provided in the vicinity of the outdoor heat exchanger and a flow control valve in the middle of the heat exchanger for control. Supply pipe Refrigerant side passage pipe connected to the refrigerant return pipe, the opening of the flow control valve based on the temperature of the indoor heat exchanger during cooling operation or the pressure of the low pressure side gaseous refrigerant sucked into the compressor A first configuration comprising a controller for adjusting the

Refrigerant connected to the indoor heat exchanger via the control heat exchanger with a control heat exchanger installed in the vicinity of the outdoor heat exchanger and a flow control valve on the way. A refrigerant side pipe connecting a supply pipe and a refrigerant return pipe, and a controller for adjusting the opening of the flow control valve based on the pressure of the high-pressure side gaseous refrigerant discharged from the compressor during the heating operation. By providing the engine-driven air conditioner of the second configuration described above, the problems of the above-described conventional technology are solved.

[0009]

[Action]

In the case of claim 1, when the flow control valve is opened, a part of the high-pressure liquid refrigerant that has been heat-exchanged with the outside air in the outdoor heat exchanger and has been liquefied and supplied to the indoor heat exchanger passes through the refrigerant side pipe. The amount of refrigerant supplied to the indoor heat exchanger through the refrigerant return pipe is reduced, so that the latent heat of vaporization in the indoor heat exchanger is reduced.

Further, the liquid refrigerant supplied to the refrigerant return pipe through the refrigerant side pipe exchanges heat with high temperature indoor air in the indoor heat exchanger, and is mixed with the gas refrigerant whose temperature has risen in the refrigerant return pipe. This evaporates and raises the refrigerant pressure in this part. This also suppresses the evaporation action of the refrigerant in the indoor heat exchanger and reduces the generation of latent heat of vaporization, so that the indoor heat exchanger is prevented from falling into a supercooled state.

In the case of claim 2, when the flow control valve is opened,
Part of the high-pressure, high-temperature gaseous refrigerant supplied to the indoor heat exchanger flows into the refrigerant bypass pipe, exchanges heat with the outside air in the control heat exchanger and condenses, and then the indoor heat exchanger is closed. The liquid refrigerant that has passed through is joined by the refrigerant return pipe and flows into the outdoor heat exchanger, so there is no abnormal decrease in the evaporation pressure of the refrigerant in the outdoor heat exchanger, and this prevents freezing of the outdoor heat exchanger. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an engine driven air conditioner according to the present invention will be described in detail below with reference to FIG. In the figure, for example, 1 is a gas engine that uses city gas as fuel (hereinafter simply referred to as engine), 2 is a compressor driven by receiving the driving force of this engine through a flexible joint, 3 is a four-way valve, 4 is indoor heat An exchanger, 5 is an indoor electrically operated valve, 6 is a receiver tank, 7 is an outdoor electrically operated valve, 8 is an outdoor heat exchanger, and 9 is an accumulator. A cooling circuit A shown by a solid line and a heating circuit B shown by a broken line are sequentially connected via 10. In the outdoor heat exchanger 8, 11 is a cooling fan for promoting heat exchange between the refrigerant and the outside air,
12 is a strainer.

Reference numeral 13 is a temperature sensor installed in the central portion of the indoor heat exchanger 4, and 14 and 15 are the refrigerant pipes 10 connected to the indoor heat exchanger 4 to the indoor heat exchanger 4. It is a temperature sensor installed in the refrigerant inlet / outlet portion.

U1 is an indoor unit equipped with the indoor heat exchanger 4, the indoor motor-operated valve 5, and the temperature sensors 13, 14, and 15 described above. In the engine-driven air conditioner of the present invention, U1 has the above-mentioned configuration. The indoor unit has four more units, that is, U2 to U5. The refrigerating capacities of these indoor units do not have to be the same.

Reference numeral 10c is a refrigerant pipe 10a which communicates the one-way service valve 16 for exchanging refrigerant with the indoor heat exchanger 4 of each of the indoor units U1 to U5 and the four-way valve 3.
And a refrigerant pipe 10b that connects the other service valve 17 and the refrigerant pipe 10b that communicates the outdoor heat exchanger 8 with the normally closed flow control valve 18 and the control heat exchanger. 1
9 and 9. The control heat exchanger 19 is installed side by side with the outdoor heat exchanger 8.

Reference numerals 20 and 21 denote pressure sensors installed in the refrigerant pipes 10 on the refrigerant suction side and the refrigerant discharge side of the compressor 2, respectively. The refrigerant suction side gas pressure, that is, the low pressure side gas pressure, and the refrigerant discharge side gas pressure, that is, the refrigerant discharge side gas pressure. The high pressure side gas pressure is detected respectively. Further, 22 is a temperature sensor installed to detect the temperature of the low-pressure side gaseous refrigerant.

Reference numeral 23 is a liquid pipe, which is provided with a strainer 12 and a liquid valve 24 on the way, and a service valve 17
A part of the liquid refrigerant flowing in the refrigerant pipe 10b between the receiver tank 6 and the receiver tank 6 is replaced with the refrigerant pipe 1 in front of the accumulator 9.
0 is connected so that it can be appropriately supplied.

The liquid valve 24 is normally closed and opened when the refrigerant discharged from the compressor 2 to the refrigerant pipe 10 exceeds a predetermined temperature, for example, 115 ° C.,
A refrigerant having a low temperature is supplied to the compressor 2 to prevent the refrigerant from overheating.

Reference numeral 25 is a controller provided with a rotation speed control section 25a for controlling the rotation speed of the engine 1 and an opening degree control section 25b for controlling the opening degree of the flow rate control valve 18, and the set room temperature and the above Based on the data measured by each sensor, the rotation speed of the engine 1 and the opening degree of the flow control valve 18 are adjusted.

When the four-way valve 3 is set to the heating mode, the high-temperature high-pressure gaseous refrigerant compressed by the compressor 2 and discharged to the refrigerant pipe 10 passes through the refrigerant pipe 10a and reaches the indoor heat exchanger 4. Is heated to heat the room air by exchanging heat with room air having a low temperature.
Then, the liquefied refrigerant is decompressed by the outdoor motor-operated valve 7 of the refrigerant pipe 10b, exchanges heat with the outside air in the outdoor heat exchanger 8 to evaporate, and is circulated to the compressor 2 for circulation of the refrigerant. The refrigerant pipe 10a is a refrigerant supply pipe, the refrigerant pipe 10
b serves as a refrigerant return pipe.

On the other hand, when the four-way valve 3 is set in the cooling mode, the high temperature and high pressure gaseous refrigerant discharged from the compressor 2 to the refrigerant pipe 10 is first supplied to the outdoor heat exchanger 8 where the temperature is low. It is cooled and liquefied by the outside air, and the liquefied refrigerant is supplied to the indoor heat exchanger 4 through the refrigerant pipe 10b. The refrigerant that has flowed into the indoor heat exchanger 4 is decompressed by the indoor motor-operated valve 5 that has passed through first, so it deprives the indoor air of evaporation heat and evaporates, and then returns to the compressor 2 through the refrigerant pipe 10a. Therefore, in this case, the refrigerant pipe 10b serves as the refrigerant supply pipe and the refrigerant pipe 10a serves as the refrigerant return pipe.

In the engine-driven air conditioner of the present invention having the above-mentioned structure, the indoor heat exchanger 4 functions as a refrigerant evaporator as described above when it is subjected to the cooling operation, and first the controller 25 rotates. The number control unit 25a responds to the difference between the set temperature and the indoor temperature, and also operates the indoor unit U.
The rotation speed of the compressor 2, that is, the rotation speed of the engine 1 is controlled according to the total refrigerating capacity of 1 to U5.

For example, if the cooling load decreases due to a decrease in the intake air temperature of the indoor heat exchanger 4 or a decrease in the number of operating indoor heat exchangers 4, the rotation of the engine 1 will be accompanied by a decrease in the cooling load. Gradually reduce the number.

However, if the cooling load is further reduced after the engine speed of the engine 1 is minimized, the evaporation pressure of the refrigerant in the indoor heat exchanger 4 further decreases and the evaporation temperature further decreases. Becomes 0 ° C. or less, and frost adheres to the indoor heat exchanger 4 to lower the heat exchange efficiency.

A control signal transmitted by the opening control section 25b of the controller 25 so that the lowest temperature among the temperatures measured by the temperature sensors 13, 14, and 15 does not fall below a predetermined temperature, for example, 0 ° C. The opening degree of the flow control valve 18 is adjusted based on the above.

When the flow control valve 18 is opened, it is liquefied by heat exchange with the outside air in the outdoor heat exchanger 8, and the refrigerant pipe 1
A part of the high-pressure liquid refrigerant that has been supplied to the indoor heat exchanger 4 through 0b passes through the refrigerant side pipe 10c (the flow control valve 18,
The generation of evaporation latent heat in the indoor heat exchanger 4 is reduced by flowing through the control heat exchanger 19) to the refrigerant pipe 10a and decreasing the amount of refrigerant supplied to the indoor heat exchanger 4.

Further, the refrigerant pipe 1 passes through the refrigerant side pipe 10c.
The liquid refrigerant supplied to 0a is heat-exchanged with the high-temperature indoor air in the indoor heat exchanger 4, and is evaporated by being mixed with the gaseous refrigerant whose temperature has risen in the refrigerant pipe 10a. To raise. Due to this, the indoor heat exchanger 4
Since the evaporation of the refrigerant is suppressed and the generation of latent heat of evaporation is reduced, the indoor heat exchanger 4 is surely prevented from falling into a supercooled state.

The upper limit of the opening of the flow control valve 18 is
The degree of superheat calculated based on the data measured by the pressure sensor 20 and the temperature sensor 22 installed on the refrigerant inlet side of the compressor 2 is limited so as to maintain a predetermined value, for example, 5 deg or more.

Further, the flow control valve 18 is opened and closed by replacing the temperature measured by the temperature sensors 13, 14, 15 with the pressure of the low-pressure side gaseous refrigerant measured by the pressure sensor 20 to a predetermined pressure,
For example, it is possible to control so as not to fall below 400 kPa.

On the other hand, when the engine-driven air conditioner having the above structure is used for heating operation, the refrigerant discharge pressure from the compressor 2 measured by the pressure sensor 21, that is, the pressure of the high-pressure side gaseous refrigerant is a predetermined pressure, For example, the rotation speed control unit 2 of the controller 25 should not exceed 2.1 MPa.
First, 5a controls the rotation speed of the engine 1.

For example, when the heating load decreases due to a rise in the intake air temperature of the indoor heat exchanger 4 or a decrease in the number of operating indoor heat exchangers 4, the engine 1 will respond to the decrease in the heating load. Gradually reduce the rotation speed.

However, if the cooling load is further reduced after controlling the engine speed to the minimum, the indoor heat exchanger 4
, The condensing pressure of the refrigerant is further increased, so that the amount of the refrigerant flowing into the outdoor heat exchanger 8 through the refrigerant pipe 10b is further reduced, which reduces the evaporation pressure of the refrigerant in the outdoor heat exchanger 8. Because it may freeze,

Based on a control signal transmitted from the opening control section 25b of the controller 25, the pressure sensor 21 does not exceed a predetermined pressure, for example, 2.1 MPa, of the pressure of the high-pressure side gaseous refrigerant being measured. The opening degree of the flow rate control valve 18 is adjusted.

When the flow control valve 18 is opened, the refrigerant pipe 10
A part of the high-pressure / high-temperature gaseous refrigerant that has flowed through a and is being supplied to the indoor heat exchanger 4 flows to the refrigerant side pipe 10c and is heat-exchanged with the outside air in the control heat exchanger 19 to be condensed, After that, the liquid refrigerant that has passed through the indoor heat exchanger 4 merges with the refrigerant pipe 10b and flows into the outdoor heat exchanger 8. Therefore, an abnormal decrease in the evaporation pressure of the refrigerant in the outdoor heat exchanger 8 is avoided, and As a result, there is no fear that the outdoor heat exchanger 8 freezes.

Since the temperature measured by the temperature sensor 13 installed in the center of the indoor heat exchanger 4 is almost equal to the condensation temperature of the refrigerant, the temperature measured by the temperature sensor 13 should be constant. It may be provided so as to control the opening degree of the flow rate control valve 18.

Further, since the present invention is not limited to the above-mentioned embodiments, various modifications can be made without departing from the spirit of the claims. For example, the connecting portion between the refrigerant side pipe 10c and the refrigerant pipe 10b may be between the service valve 17 and the receiver tank 6 or may be the side facing the indoor heat exchanger 8.

[0037]

As described above, according to the engine-driven air conditioner of the present invention, even if the load is greatly reduced during either the cold or warm air conditioning operation, after the engine speed is lowered to the minimum. The stable air conditioning operation can be continued only by adjusting the opening degree of the flow rate control valve provided in the refrigerant side pipe.

[Brief description of drawings]

FIG. 1 is a system diagram of an engine-driven air conditioner.

[Explanation of symbols]

 1 (gas) engine 2 compressor 3 four-way valve 4 indoor heat exchanger 5 indoor electric valve 6 receiver tank 7 outdoor electric valve 8 outdoor heat exchanger 9 accumulator 10 · 10a · 10b refrigerant pipe 10c refrigerant bypass pipe 11 cooling fan 12 Ftrainer 13 ・ 14 ・ 15 Temperature sensor 16 ・ 17 Service valve 18 Flow control valve 19 Control heat exchanger 20 ・ 21 Pressure sensor 22 Temperature sensor 23 Liquid piping 24 Liquid valve 25 Controller 25a Rotation speed control unit 25b Opening control unit A Cooling circuit B Heating circuit U1, U2, U3, U4, U5 Indoor unit

Claims (2)

[Claims] 1. A compressor driven by an engine,
Four-way valve, indoor heat exchanger, receiver tank, outdoor electric valve,
In an engine-driven air conditioner in which an outdoor heat exchanger, an accumulator, etc. are sequentially connected via a refrigerant pipe to form a cooling / heating circuit, a control heat exchanger installed close to the outdoor heat exchanger. And, via the control heat exchanger provided with a flow rate control valve on the way, a refrigerant bypass pipe connecting the refrigerant supply pipe and the refrigerant return pipe connected to the indoor heat exchanger, and the cooling medium during the cooling operation. A controller that adjusts the opening of the flow control valve based on the temperature of the indoor heat exchanger or the pressure of the low-pressure side gaseous refrigerant sucked into the compressor, the engine-driven air Harmony device. 2. A compressor driven by an engine,
Four-way valve, indoor heat exchanger, receiver tank, outdoor electric valve,
In an engine-driven air conditioner in which an outdoor heat exchanger, an accumulator, etc. are sequentially connected via a refrigerant pipe to form a cooling / heating circuit, a control heat exchanger installed close to the outdoor heat exchanger. And, a refrigerant side pipe connecting the refrigerant supply pipe and the refrigerant return pipe connected to the indoor heat exchanger, which is provided with a flow rate control valve in the middle, through the control heat exchanger, and the heating side during the heating operation. An engine-driven air conditioner, comprising: a controller that adjusts the opening of the flow control valve based on the pressure of the high-pressure side gaseous refrigerant discharged from the compressor.