JPH07127932A - Heat pump device - Google Patents

Abstract

(57) [Summary] [Structure] The compressor lubricating oil mixed in the discharge high-pressure gas refrigerant Rh from the compressors Cmp1 and Cmp2 is separated and extracted,
A separating / refluxing means K for returning the separated and extracted lubricating oil to each of the compressors Cmp1 and Cmp2 is provided, and a cooling means F for cooling the lubricating oil to be returned to each of the compressors Cmp1 and Cmp2 by the separating / refluxing means K is provided. Heat pump device. [Effect] Since the high-temperature lubricating oil separated and extracted from the discharged high-pressure gas refrigerant can be cooled and returned to the suction side of the compressor, the returning lubricating oil does not unnecessarily heat the compressor and It is possible to provide a heat pump device in which the inconvenience that a high pressure abnormality of the compressor occurs due to an increase in the side temperature is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention separates and recirculates compressor lubricating oil mixed in high-pressure gas refrigerant discharged from a compressor, and separates and recirculates the separated and extracted lubricating oil to each of the compressors. A heat pump device provided with the means.

[0002]

2. Description of the Related Art Conventionally, in this type of heat pump device, the separation / reflux means returns the lubricating oil separated and extracted from the high-pressure gas refrigerant discharged from the compressor to each of the compressors in the same temperature state. Was configured as.

[0003]

However, according to the above-mentioned prior art, since the lubricating oil separated and extracted from the discharged high-pressure gas refrigerant has an extremely high temperature, the temperature of the lubricating oil on the suction side of the compressor remains unchanged. When you put it back, the compressor heats up,
There is a disadvantage that the discharge side temperature rises and a high pressure abnormality of the compressor may occur. An object of the present invention is to eliminate the above-mentioned conventional drawbacks.

[0004]

A first characteristic configuration of the heat pump device according to the present invention is that a cooling means is provided for cooling the lubricating oil returned to each of the compressors by the separating / refluxing means.

The second and third characteristic constitutions of the heat pump device according to the present invention specify a preferable concrete constitution for carrying out the first characteristic constitution,

A second characteristic configuration is that an accumulator for separating and extracting a liquid component from the refrigerant to be sucked into the compressor and storing the separated liquid component is provided, and the cooling means separates the liquid refrigerant in the accumulator from the separating / refluxing means. It is composed of a heat exchanger for exchanging heat with the lubricating oil.

A third characteristic configuration is that a lubricating oil passage in the separating / refluxing means is provided with a throttle passage for providing a pressure difference between an upstream portion on the compressor discharge side and a downstream portion on the compressor suction side. The heat exchanger is configured to exchange heat between the lubricating oil and the liquid refrigerant in this throttle passage.

[0008]

According to the first characteristic configuration of the present invention, since the cooling means for cooling the lubricating oil returned to each of the compressors by the separating / refluxing means is provided, the high temperature gas separated and extracted from the discharged high pressure gas refrigerant is cooled. The lubricating oil can be cooled and returned to the suction side of the compressor.

According to the second characteristic configuration, the accumulator for separating and extracting and storing the liquid component from the refrigerant to be sucked into the compressor is provided, and the cooling means separates and lubricates the liquid refrigerant in the accumulator and the separating / refluxing means. Since it is composed of a heat exchanger for exchanging heat with oil, the high temperature lubricating oil from the separation / reflux means can be cooled by the liquid refrigerant in the accumulator, and the liquid refrigerant is heated by the heat radiated by the lubricating oil. Can be vaporized again.

According to the third characteristic configuration, since the heat exchanger is configured to exchange heat between the lubricating oil and the liquid refrigerant in the throttle passage, it is not necessary to separately provide a heat exchanger.

[0011]

According to the first characteristic configuration of the present invention, the high temperature lubricating oil separated and extracted from the discharged high pressure gas refrigerant can be cooled and returned to the suction side of the compressor. It is possible to provide a heat pump device in which the compressor is not unnecessarily heated and the inconvenience that a high pressure abnormality of the compressor occurs due to an increase in the discharge side temperature is solved.

According to the second characteristic constitution, the high temperature lubricating oil from the separating and recirculating means can be cooled by the liquid refrigerant in the accumulator, and the liquid refrigerant is vaporized again by the heat radiated by the lubricating oil. Therefore, first, the return lubricating oil can be cooled at a temperature close to the refrigerant to be sucked into the compressor without the need for a separate dedicated cold heat source for cooling the lubricating oil by the cooling means. Further, since the storage amount of the liquid refrigerant in the accumulator can be reduced, so-called liquid back to the compressor is further prevented, and the safe capacity of the accumulator (the capacity capable of storing the liquid refrigerant) is reduced. This can contribute to downsizing of the device and reduction of manufacturing cost. Furthermore,
The heat radiated by the lubricating oil becomes latent heat when the liquid refrigerant is vaporized, and therefore the temperature of the suction object refrigerant is not increased by cooling the lubricating oil.

According to the third characteristic configuration, it is not necessary to separately provide a heat exchanger, so that it is possible to provide a heat pump device in which the structure is simplified by the combined use of parts and the manufacturing cost is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a heat pump type air conditioner as an example of a heat pump device, where Uo is an outdoor unit and Ui is a plurality of indoor units that supply air supply SA to an air conditioning target area. Although not illustrated, the target area for air conditioning includes a plurality of indoor units Ui.
May be configured to individually supply the supply air SA to each of a plurality of air conditioning target areas (for example, a plurality of private rooms), or to one air conditioning target area (for example, a large room). A plurality of indoor units Ui may be configured to supply the supply air SA.

Between the outdoor unit Uo and the indoor unit Ui, a high-pressure gas main pipe Gh for flowing a high-pressure gas refrigerant Rh, a low-pressure gas main pipe Gc for flowing a low-pressure gas refrigerant Rc, and a liquid for circulating a liquid refrigerant. Three pipes, which are the main pipe W, are provided. The outdoor unit Uo and the plurality of indoor units Ui are configured to be able to receive the refrigerant via the above-mentioned three pipes, and constitute a refrigerant circulation circuit.

The indoor unit Ui is provided with an air supply SA for the air conditioning target area.
An indoor heat exchanger Ni for controlling the temperature, an air supply fan F1 for supplying the air supply SA whose temperature is controlled by the indoor heat exchanger Ni to an air conditioning target area, and an expansion valve corresponding to each indoor heat exchanger Ni. e
x1 and is equipped.

The outdoor unit Uo includes an outdoor heat exchanger No that uses the outdoor air OA as the air to be absorbed and radiated, an outdoor fan F2 that ventilates the outdoor air OA to the outdoor heat exchanger No, and an outdoor heat exchanger No. Corresponding expansion valve ex2 and two compressors Cmp
1, Cmp2, an accumulator Ac that separates and extracts a liquid component from a low-pressure gas refrigerant Rc as a suction target refrigerant of the compressors Cmp1 and Cmp2, and a discharge high-pressure gas refrigerant Rh of the compressors Cmp1 and Cmp2. The lubricating oil is separated and extracted, and the separated and extracted lubricating oil is compressed by the compressors Cmp1 and Cmp.
The separation / reflux means K for returning to each of the two and the control section H of the present heat pump type air conditioner are provided.

Reference numerals v1 to v9 are switching valves for switching the refrigerant circuit according to the operation mode and the like.

The expansion valves ex1 and ex2 function as the original refrigerant expansion means when the liquid refrigerant flows toward the corresponding heat exchanger Ni or No, while the expansion valves ex1 and ex2 meanwhile correspond to the corresponding heat exchanger Ni or No. When the liquid refrigerant flows toward the side away from the switch, the switch is configured so as to simply function as a flow rate adjusting valve.

The accumulator Ac is composed of two compressors Cmp.
1 and Cmp2 are interposed in the middle portion of the low pressure gas introduction passage rc for feeding the low pressure gas refrigerant Rc. At the bottom of the accumulator Ac, the liquid component separated from the low-pressure gas refrigerant Rc is stored, and the lubricating oil Lo of the compressor stays at the relatively lower part of the stored liquid component, and at the relatively upper part. The liquid refrigerant Lr stays in the.

The gas refrigerant outlet side of the accumulator Ac has a U-shaped tube structure, and the lower bent portion of the U-shaped tube u is
It is adapted to be immersed in a layer of lubricating oil Lo that accumulates at the bottom. An oil return hole a is provided in the lower bent portion of the U-shaped pipe u, and the lubricating oil Lo is sucked into the U-shaped pipe u from the oil return hole a as the low-pressure gas refrigerant Rc is taken out. The lubricating oil Lo staying together with the refrigerant Rc is taken out. The low pressure gas refrigerant Rc and the lubricating oil Lo extracted from the accumulator Ac are compressed by the compressor Cmp.
1 and Cmp2, the refrigerant is appropriately distributed to the refrigerant suction pipes r1 and r2 of the compressors Cmp1 and Cmp2, and is sucked into the compressor.

A hole b provided in the upper part of the U-shaped tube u
Is a pressure balancing communication hole for preventing the liquid content in the accumulator Ac from flowing into the compressor from the oil return hole a when the pressure of the evaporator rises when the compressor is stopped.

The control unit H is mainly composed of a microcomputer, and is configured so as to be able to control various operations of the heat pump type air conditioner by software built therein.

The separating / refluxing means K is composed of compressors Cmp1 and Cmp2.
The oil separator Os for separating and extracting the lubricating oil mixed in the high pressure gas refrigerant Rh discharged from the compressor and the lubricating oil separated and extracted by the oil separator Os are compressed by the compressors Cmp1, Cmp.
It is composed of a return path ro for returning to each of the two.

The oil separator Os is used for both compressors C.
The lubricating oil mixed in the high-pressure gas refrigerant Rh from mp1 and Cmp2 is separated and extracted, the high-pressure gas refrigerant Rh is sent to the high-pressure gas supply passage rh, and the separated lubricating oil is returned to the return passage ro.
Is configured to be delivered to.

The return passage ro is branched at its tip end portion and connected to the middle portions of the refrigerant suction pipes r1 and r2 of the compressors Cmp1 and Cmp2, respectively. When the low-pressure gas refrigerant Rc is sucked along with the operation of the compressors Cmp1 and Cmp2, the return path r
The lubricating oil in o is also sucked, and together with the low pressure gas refrigerant Rc,
The lubricating oil is returned to the compressors Cmp1 and Cmp2.

Flow rate adjusting valves 2 and 3 for adjusting the flow rate of the lubricating oil are provided at the branched end portions of the return path ro. The flow rate adjusting valves 2 and 3 are configured so that the distribution ratio of the return lubricating oil from the oil separator Os to the compressors Cmp1 and Cmp2 can be changed and adjusted by adjusting the valve openings of the flow rate adjusting valves 2 and 3.

An intermediate portion of the return path ro passes through the accumulator Ac and is compressed with the upstream portion of the compressor discharge side so that the discharge side and the suction side of the compressors Cmp1 and Cmp2 are not pressure-shorted. A decompression thin tube 1 is interposed as a throttle passage that gives a pressure difference to the downstream side of the machine suction side.

The decompression thin tube 1 is provided so as to be submerged in a layer of the liquid refrigerant Lr retained in the accumulator Ac. As a result, in the depressurizing thin tube 1, the high temperature lubricating oil from the oil separator Os and the liquid refrigerant Lr in the accumulator Ac are heat-exchanged, the high temperature lubricating oil is cooled by the liquid refrigerant Lr, and the lubricating oil radiates heat. The liquid refrigerant Lr is configured to be vaporized by the heat generated.

Therefore, the accumulator Ac and the decompression thin tube 1 constitute a heat exchanger F for exchanging heat between the liquid refrigerant Lr in the accumulator Ac and the lubricating oil separated by the separating / refluxing means K. Is a cooling means for cooling the lubricating oil returned to the compressors Cmp1 and Cmp2 by the separation / reflux means K.

Incidentally, near the discharge ports of the compressors Cmp1 and Cmp2, temperature sensors S1 and S2 for detecting the temperatures Th1 and Th2 of the discharge high-pressure gas refrigerant Rh of the compressors Cmp1 and Cmp2 are provided and separated. The flow rate adjusting valves 2 and 3 of the reflux means K are controlled by the control unit H to detect the temperature (Th1 or T).
Adjustment control is performed so that the amount of lubricating oil returned to the compressor (Cmp1 or Cmp2) whose h2) is increasing increases.

[Other Embodiment] The cooling means is a heat exchanger F for exchanging heat in the decompression thin tube 1 in the accumulator Ac.
However, the heat radiation target and the mounting position can be changed as appropriate. For example, a heat exchanger that radiates heat to the outside air OA or the like may be provided in the middle of the return path ro.

The structure of the separating / refluxing means K can be appropriately changed. For example, the flow rate adjusting valves 2 and 3 may be omitted. Further, instead of the flow rate adjusting valves 2 and 3, a switching valve or an interrupting valve that selectively switches the flow of the branched distal end side portion of the return path ro may be provided.

The heat pump device is not limited to the air conditioner.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall configuration of a heat pump type air conditioner.

[Explanation of symbols]

 Ac Accumulator Cmp1 Compressor Cmp2 Compressor F Heat exchanger (cooling means) K Separation / reflux means Rc Suction target refrigerant Rh Discharge high-pressure gas refrigerant 1 Throttling path

Claims (3)

[Claims] 1. A compressor lubricating oil mixed in a discharge high-pressure gas refrigerant (Rh) from a compressor (Cmp1, Cmp2) is separated and extracted, and the separated and extracted lubricating oil is used as the compressor (C).
mp1, Cmp2) and a separate reflux means (K) for returning to each of the compressors (Cmp1, Cmp) by the separate reflux means (K).
A heat pump device provided with cooling means (F) for cooling the lubricating oil returned to each of mp2). 2. An accumulator (Ac) for separating and extracting a liquid component from a refrigerant (Rc) to be sucked into the compressor (Cmp1, Cmp2) and storing the separated liquid component is provided, and the cooling means is provided in the accumulator (Ac). A heat exchanger (F) for exchanging heat between the liquid refrigerant and the lubricating oil separated by the separating / refluxing means (K).
The heat pump device described. 3. A throttle passage (1) for providing a pressure difference between an upstream side portion on the compressor discharge side and a downstream side portion on the compressor suction side in the lubricating oil system passage in the separation / reflux means (K). The heat pump device according to claim 2, wherein the heat exchanger (F) is provided so as to exchange heat between the lubricating oil and the liquid refrigerant in the throttle passage (1).