JPH0835731A - Heat pump - Google Patents

Abstract

PURPOSE:To increase the capacity control range by providing two outdoor heat exchangers, and using one of the exchangers as an evaporator at the time of cooling or as a condenser at the time of heating when air conditioning load is a set value or less. CONSTITUTION:At the time of heating with high load, refrigerant fed from a compressor 2 is fed through a four-way valve 5, an indoor heat exchanger gas line 4, indoor units 12, a receiver tank 9, a main outdoor heat exchanger line 3 and a suboutdoor heat exchanger line 3a, a main outdoor heat exchanger 6a and a sub outdoor heat exchanger 6b, a bypass line 15 and the valve 5 to the compressor 2, the exchangers 6a, 6b are used as evaporators to maintain a heating capacity large. On the other hand, at the time of heating with low load, the refrigerant fed to the line 4 is branched to the unit 12 side and the line 15 side as it is, the exchanger 6b is used as the condenser, thereby reducing the heating capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump device for operating a plurality of indoor units by using one outdoor unit.

[0002]

2. Description of the Related Art A heat pump device has a structure in which a compressor and an outdoor heat exchanger are incorporated in an outdoor unit and a cooling operation and a heating operation are performed by switching a four-way valve.

FIG. 7 shows this conventional heat pump apparatus, in which 1 is an outdoor unit, and in the outdoor unit 1, a compressor 2, a main outdoor heat exchanger line 3, an indoor heat exchange gas line 4, A four-way valve 5, an outdoor heat exchanger 6, an electronic expansion valve 7, an electronic expansion valve bypass line 8 with a check valve 8a, a receiver tank 9, and a high / low pressure bypass line 10 with a high / low pressure bypass switching solenoid valve 11 are incorporated. There is. On the other hand, in the indoor unit 12, the indoor heat exchanger 13 and the electronic expansion valve 1
4 is incorporated.

In the case of the above-mentioned conventional heat pump device, switching between cooling and heating is performed by the four-way valve 5, and when the air conditioning load is small, the rotation speed of the prime mover of the compressor 2 is controlled from high speed rotation to low speed rotation, and refrigerant is supplied. This is dealt with by bypassing via the high and low pressure bypass line 10.

[0005]

However, when the above control method is adopted, there are the following drawbacks.

A. When using an engine as a prime mover,
When trying to increase the rotation speed control range, the engine vibration becomes large in the low rotation speed range, so that it cannot be used at a very low rotation speed.

B. If the bypass amount of the refrigerant in the high and low pressure portions is excessively increased, the suction temperature and the discharge temperature of the compressor 2 become high and the durability of the compressor 2 deteriorates, so that the bypass amount cannot be increased too much.

C. If the capacity control range cannot be increased,
I. In the small capacity indoor unit 12, only one unit cannot be operated. The refrigerant high pressure may become too high during heating when the indoor and outdoor temperatures are high. When the indoor and outdoor temperatures are low, the refrigerant low pressure may become too low during cooling, and the indoor heat exchanger 13 may freeze.

An object of the present invention is to eliminate the above-mentioned defects a to c in a heat pump device.

[0010]

The structure of the heat pump device according to the present invention is as follows.

1. When two outdoor heat exchangers are installed and the air conditioning load is larger than the set value, the refrigerant is passed through both outdoor heat exchangers and this outdoor heat exchanger is used as a condenser or evaporator, and the air conditioning load is below the set value. In the above case, one of the outdoor heat exchangers is used as an evaporator during cooling, and is used as a condenser during heating.

2. In the outdoor unit, the main outdoor heat exchanger line and the indoor heat exchanger gas line are connected by a bypass line with a switching circuit, and the bypass line is branched to provide a sub outdoor heat exchanger line. Is connected to the downstream side of the receiver tank, a main outdoor heat exchanger is attached to the main outdoor heat exchanger line side, a sub outdoor heat exchanger is attached to the sub outdoor heat exchanger line side, and the main outdoor heat exchanger is attached. In the heat exchanger line and the sub outdoor heat exchanger line, an electronic expansion valve is installed between the main and sub outdoor heat exchanger and the receiver tank, and an electronic expansion valve bypass line with a check valve that bypasses the electronic expansion valve is installed. Furthermore, between the electronic expansion valve bypass line and the receiver tank, the main outdoor heat exchanger line and the Conclusion In control bypass lines with circuit switches the outdoor heat exchanger-line, when the air conditioning load detected by the air conditioning load detector is equal to or greater than the set value,
Flowing the refrigerant through both the main and sub outdoor heat exchangers, the air conditioning load is below a set value, switching the refrigerant flow so that the sub outdoor heat exchanger side functions as an evaporator during cooling, A heat pump device comprising a controller for switching the flow of the refrigerant so as to function as a condenser during heating.

[0013]

[Operation] When the air conditioning load is above the set value, the controller carries out a high load operation by passing the refrigerant through the two main and sub outdoor heat exchangers, and when the air conditioning load is below the set value, the heating operation In the case, the main outdoor heat exchanger side is operated as an evaporator, the sub is operated as a condenser, and in the case of cooling, the main outdoor heat exchanger is operated as a condenser and the sub is operated as an evaporator. During this operation, the rotation of the prime mover that drives the compressor is also controlled at the same time, so that the control range for the load can be widened.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a heat pump device embodying the present invention.
2 is an explanatory diagram of a switching circuit, FIG. 3 is an explanatory diagram of a high load heating operation, FIG. 4 is an explanatory diagram of a low load heating operation, FIG. 5 is an explanatory diagram of a high load cooling operation, and FIG. 6 is a low load. It is an explanatory view at the time of cooling operation. 1 to 6, 1 is an outdoor unit, 2 is
Is a compressor, 3 is a main outdoor heat exchanger line, 4 is an indoor heat exchanger gas line, 5 is a four-way valve, 6a is a main outdoor heat exchanger attached to the main outdoor heat exchanger line 3, and 7a is an electronic expansion valve , 8a is an electronic expansion valve bypass line with a check valve 8b, 9 is a receiver tank, 15 is a bypass line connecting the main outdoor heat exchanger line 3 and the indoor heat exchanger gas line 4, 3a is a bypass line 15 A sub-outdoor heat exchanger line connected to the downstream side of the receiver tank 9, 6b is a sub-outdoor heat exchanger attached to the sub-outdoor heat exchanger line 3a, and 7a 'is an electron on the sub-outdoor heat exchanger line 3a side. Expansion valve, 8a 'is a check valve 8
This is an electronic expansion valve bypass line with b '. Reference numeral 16 is a control bypass line connecting the main outdoor heat exchanger line 3 and the sub outdoor heat exchanger line 3a on the downstream side of the main outdoor heat exchanger line 3 and the main and sub outdoor heat exchangers 6a and 6b. As shown in FIG. 2, the switching circuit 17 includes a check valve 17a and a switching valve 1 as shown in FIG.
This is a configuration in which 7b for the round trip is incorporated. In the figure, 12 is an indoor unit, 13 is an indoor heat exchanger, 14 is an electronic expansion valve, 18 is a controller, and this controller 18 performs the following operation control.

Heating high load operation (Fig. 3) In this operation, as shown in Fig. 3, the refrigerant sent from the compressor 2 is a four-way valve 5 → indoor heat exchanger gas line 4 → each indoor unit 12 → receiver. Tank 9 → Main outdoor heat exchanger line 3 and sub outdoor heat exchanger line 3a → Main outdoor heat exchanger 6a and sub outdoor heat exchanger 6b → Bypass line 15 → Four-way valve 5 → Flow from compressor 2 to indoor unit 12 side The indoor heat exchanger 13 functions as a condenser,
The main and sub outdoor heat exchangers 6a and 6b function as evaporators.

Heating low load operation (FIG. 4) In this operation, the refrigerant sent from the compressor 2 leaves the four-way valve 5 and flows into the indoor heat exchanger gas line 4 as it is. Flow to the side of the sub-outdoor heat exchanger line 3a
Passes through the sub outdoor heat exchanger 6b and merges with the refrigerant returned from one indoor unit 12, and then the receiver tank 9 → the main outdoor heat exchanger line 3 → the main outdoor heat exchanger 6a → the four-way valve 5 → the compressor 2 Return. At this time, the sub outdoor heat exchanger 6b functions as a condenser.

Cooling high load operation (FIG. 5) In this operation, as shown in FIG. 5, the refrigerant sent from the compressor 2 is a four-way valve 5 → main outdoor heat exchanger line 3 → main outdoor heat exchanger 6a. → Electronic expansion valve bypass line 8a → Simultaneous with the flow of the receiver tank 9, bypass line 15 → sub outdoor heat exchanger 6a → control bypass line 16 → receiver tank 9 → each indoor unit 12 → indoor heat exchanger gas line 4 → four-way Flowing from the valve 5 to the compressor 2, the indoor heat exchanger 13 on the indoor unit 12 side functions as an evaporator, and the main and sub outdoor heat exchangers 6a and 6b function as condensers.

Cooling low load operation (FIG. 6) In this operation, the refrigerant sent from the compressor 2 is a four-way valve 5 → main outdoor heat exchanger line 3a → main outdoor heat exchanger 6a → electronic expansion valve bypass line 8a. → Receiver tank 9 → One indoor unit 12 → Indoor heat exchanger gas line 4 → Four-way valve 5 → Compressor 2 and sub outdoor heat by bypassing the indoor unit 12 from the main outdoor heat exchanger line 3a A flow from the exchanger line 3a, the sub-outdoor heat exchanger 6b, the four-way valve 5 and the compressor 2 is generated. At this time, the sub outdoor heat exchanger 6b acts as an evaporator.

The above-described operation is performed by the controller 18 by switching the switching valve 17b in each switching circuit 17, and the load is detected by the operation signal from each indoor unit 12, and this signal is used. Based on the above, the load is calculated, which operation is to be performed is determined, and the switching circuit 17 is controlled.

[0020]

The effects of the present invention are as follows.

A. The capacity control range can be expanded by combining the rotational speed control of the prime mover that drives the compressor, the bypass of the high and low pressure parts of the refrigerant, and the device of the present invention.

B. Since the capacity control range can be increased,
I. It is possible to operate only one small capacity indoor unit. It is possible to prevent the refrigerant high pressure from becoming too high during heating when the indoor and outdoor temperatures are high. The refrigerant low pressure can be prevented from becoming too low during cooling when the indoor and outdoor temperatures are low, and as a result, freezing of the indoor heat exchanger can be prevented.

C. This durability is increased because the compressor is not stressed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a heat pump device according to the present invention.

FIG. 2 is an explanatory diagram of a switching circuit.

FIG. 3 is an explanatory diagram during high-load heating operation.

FIG. 4 is an explanatory diagram during heating low load operation.

FIG. 5 is an explanatory diagram at the time of cooling high load operation.

FIG. 6 is an explanatory diagram at the time of cooling low load operation.

FIG. 7 is an explanatory diagram of a conventional heat pump device.

[Explanation of symbols]

 1 outdoor unit 2 compressor 3 main outdoor heat exchanger line 3a sub outdoor heat exchanger line 4 indoor heat exchanger gas line 5 four-way valve 6a main outdoor heat exchanger 6b sub outdoor heat exchanger 7a, 7a 'electronic expansion valve 8a, 8a 'electronic expansion valve bypass line 8b, 8b' check valve 9 receiver tank 12 indoor unit 13 indoor heat exchanger 14 electronic expansion valve 15 bypass line 16 control bypass line 17 switching circuit 17a check valve 17b switching valve 18 Controller

Claims (2)

[Claims] 1. When two outdoor heat exchangers are built in, and when the air conditioning load is larger than a set value, a refrigerant is passed through both outdoor heat exchangers, and the outdoor heat exchangers are used as a condenser or an evaporator to provide air conditioning. A heat pump device configured such that one of the outdoor heat exchangers is used as an evaporator when the load is equal to or lower than a set value and is used as a condenser when heating. 2. In the outdoor unit, a main outdoor heat exchanger line and an indoor heat exchanger gas line are connected by a bypass line with a switching circuit, and the bypass line is branched to provide a sub outdoor heat exchanger line. Connecting the outdoor heat exchanger line to the downstream side of the receiver tank, attaching the main outdoor heat exchanger to the main outdoor heat exchanger line side, and attaching the sub outdoor heat exchanger to the sub outdoor heat exchanger line side, In the main outdoor heat exchanger line and the sub outdoor heat exchanger line, an electronic expansion valve is installed between the main and sub outdoor heat exchangers and the receiver tank, and an electronic expansion with a check valve that bypasses the electronic expansion valve. A valve bypass line is installed, and further heat exchange between the electronic expansion valve bypass line and the receiver tank is outside the main room. If the air conditioning load detected by the air conditioning load detector is equal to or greater than the set value by connecting the air conditioning line and the sub outdoor heat exchanger line with a control bypass line with a switching circuit,
Flowing the refrigerant through both the main and sub outdoor heat exchangers, the air conditioning load is below a set value, switching the refrigerant flow so that the sub outdoor heat exchanger side functions as an evaporator during cooling, A heat pump device comprising a controller for switching the flow of the refrigerant so as to function as a condenser during heating.