CN107906790B

CN107906790B - Air conditioner oil return system and method and air conditioner

Info

Publication number: CN107906790B
Application number: CN201711174252.6A
Authority: CN
Inventors: 曹巍; 林海佳; 尚瑞
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2017-11-22
Filing date: 2017-11-22
Publication date: 2020-04-24
Anticipated expiration: 2037-11-22
Also published as: CN107906790A

Abstract

The invention discloses an air conditioner oil return system, an air conditioner oil return method and an air conditioner, and at least solves the problem that the heat exchange effect of the system is influenced by overhigh oil return temperature in the oil return process of the air conditioner in the related technology. The disclosed oil return system of an air conditioner includes: the inlet of the first oil separator is connected with the air outlet end of a compressor in the air conditioner and is used for receiving an oil-gas mixture discharged by the compressor connected with the first oil separator and separating the oil-gas mixture; a first oil return line for transferring the oil separated by the first oil separator to a compressor in the air conditioner; and the controller is used for adjusting the air supply flow in the air supply loop of the compressor according to the air supply superheat degree of the compressor in the air conditioner during the oil return operation of the air conditioner so as to reduce the oil return temperature of the air conditioner. The invention avoids the problem that the heat exchange effect of the system is influenced by overhigh return oil temperature of the system.

Description

Air conditioner oil return system and method and air conditioner

Technical Field

The invention relates to the technical field of air conditioners, in particular to an air conditioner oil return system and method and an air conditioner.

Background

The compressor lubricating oil is a substance which plays a role in lubricating the moving parts of the compressor, can be dissolved in the refrigerant and flows in the air conditioning system along with the refrigerant. In the operation process of the air conditioner, the lubrication in the compressor enters the heat exchanger along with the refrigerant and part of the lubrication is remained in the heat exchanger, so that the lubricating oil in the compressor is possibly lost, the motor bearing and the compression cavity of the compressor cannot be effectively lubricated, the performance and the reliability of the compressor are influenced, and even the compressor is burnt. Therefore, in the operation process of the air conditioner, the lubricating oil is usually separated from the refrigerant by an oil return system and then sent back to the compressor for recycling. The conventional oil return mode is that each compressor in the air conditioner is provided with an oil separator, and an oil return port is close to an air suction port of each compressor; or the two compressors are connected in parallel and then provided with an oil separator, and the oil return of the oil separator is divided into two paths which are respectively close to the air suction ports of the two compressors. However, the mode is influenced by factors such as operation time or structural difference, so that the oil distribution of the lubricating oil is uneven, and the oil return port of the oil separator is close to the air suction port of the compressor, and during oil return, the high oil return temperature influences the heat exchange effect of the system because the lubricating oil is separated from exhaust gas in the oil separator.

Disclosure of Invention

The invention provides an air conditioner oil return system, an air conditioner oil return method and an air conditioner, and at least solves the problem that the heat exchange effect of the system is influenced by overhigh oil return temperature in the oil return process of the air conditioner in the related technology.

According to an aspect of the present invention, there is provided an oil return system of an air conditioner, including: the inlet of the first oil separator is connected with the air outlet end of a compressor in the air conditioner and is used for receiving an oil-gas mixture discharged by the compressor connected with the first oil separator and separating the oil-gas mixture; a first oil return line for transferring the oil separated by the first oil separator to a compressor in the air conditioner; and the controller is used for adjusting the air supply flow in the air supply loop of the compressor according to the air supply superheat degree of the compressor in the air conditioner when the air conditioner runs in the oil return mode so as to reduce the oil return temperature of the air conditioner.

Optionally, the air conditioner includes a first compressor and a second compressor, and the first oil return line is connected between an oil outlet of the first oil separator and an air make-up port of the second compressor.

Optionally, the air conditioner further comprises: the inlet of the second oil separator is connected with the gas outlet end of the second compressor and is used for receiving the oil-gas mixture discharged by the second compressor and separating the oil-gas mixture; and the second oil return pipeline is connected between an oil outlet of the second oil separator and an air supplementing port of the first compressor and is used for conveying the oil separated by the second oil separator to the first compressor.

Optionally, the first compressor is connected in parallel with the second compressor, and the controller is further configured to: and when the air conditioner operates in an oil return mode, controlling the first compressor and the second compressor to operate together.

Optionally, the controller adjusts the make-up air flow rate in the make-up air circuit of the compressor according to the make-up air superheat degree of the compressor in the air conditioner by: acquiring the air supplement superheat degree of the compressor; and when the air supply superheat degree of the compressor is smaller than a second preset value, controlling the opening degree of an expansion valve in the air supply loop of the compressor to be increased until the air supply superheat degree of the compressor is not larger than the first preset value and not smaller than the second preset value.

According to another aspect of the invention, an air conditioner is provided, which comprises any one of the air conditioner oil return systems.

According to still another aspect of the present invention, there is provided an oil returning method of an air conditioner, including: when the air conditioner operates in oil return mode, obtaining the air supplement superheat degree of a compressor in the air conditioner; and adjusting the air supply flow in an air supply loop of the compressor according to the air supply superheat degree of the compressor in the air conditioner so as to reduce the oil return temperature of the air conditioner.

Optionally, the air conditioner includes a first oil separator, a first compressor, a second compressor, and a first oil return line, an inlet of the first oil separator is connected to an exhaust port end of the first compressor, and the first oil return line is connected between an oil outlet of the first oil separator and an air make-up port of the second compressor.

Optionally, the air conditioner further comprises: the inlet of the second oil separator is connected with the gas outlet end of the second compressor; and the second oil return pipeline is connected between an oil outlet of the second oil separator and an air supplementing port of the first compressor and is used for conveying the oil separated by the second oil separator to the first compressor.

Optionally, the first compressor is connected in parallel with the second compressor, the method further comprising: and when the air conditioner operates in an oil return mode, controlling the first compressor and the second compressor to operate together.

Optionally, the adjusting the make-up air flow in the make-up air circuit of the compressor according to the make-up air superheat degree of the compressor comprises: and when the air supply superheat degree of the compressor is smaller than a second preset value, controlling the opening degree of an expansion valve in the air supply loop of the compressor to be increased until the air supply superheat degree of the compressor is not larger than the first preset value and not smaller than the second preset value.

According to the scheme provided by the embodiment of the application, in the oil return process of the air conditioner, the air supply flow in the air supply loop of the compressor is adjusted according to the air supply superheat degree of the compressor in the air conditioner, the heat exchange effect of the system is prevented from being influenced by overhigh temperature of return oil of the system, and the heat exchange effect of the system is improved.

Drawings

Fig. 1 is a block diagram of an oil return system of an air conditioner provided in embodiment 1 of the present application;

fig. 2 is a flowchart of an oil return method of an air conditioner provided in embodiment 2 of the present application.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

Example 1

This embodiment provides an air conditioner oil return system, and this air conditioner oil return system mainly includes following component:

the oil separator comprises an oil separator, an oil return pipeline and a controller, wherein an inlet of the oil separator is connected with an exhaust port end of a compressor in the air conditioner and used for receiving an oil-gas mixture discharged by the compressor connected with the oil separator and separating the oil-gas mixture; the oil return pipeline is used for conveying the oil separated by the oil separator to a compressor in the air conditioner, and the compressor can be any one of a plurality of compressors of the air conditioning system; the controller is used for adjusting the air supply flow in the air supply loop of the compressor according to the air supply superheat degree of the compressor in the air conditioner when the air conditioner operates in oil return so as to reduce the oil return temperature of the air conditioner.

Further, fig. 1 shows a schematic diagram of an oil return system of another air conditioner provided in this embodiment, as shown in fig. 1, the air conditioner includes an oil separator 11, an oil separator 12, an oil return solenoid valve 13, an oil return solenoid valve 14, an oil return line 15, an oil return line 16, a compressor 17, a compressor 18, a bulb 19, a bulb 110, an expansion valve 111, an expansion valve 112, and a pressure sensor 113.

When the air conditioning system operates, the air supplementing pressure (Pm) is acquired through the pressure sensor 113, the saturation temperature Tm corresponding to the air supplementing pressure is obtained, and the air supplementing temperatures T1 and T2 are acquired through the

temperature sensing bags

110 and 19. When the air conditioning system enters the oil return condition, the oil return solenoid valve 13 and the oil return solenoid valve 14 are opened, and the lubricating oil separated from the oil separator 11 and the oil separator 12 flows to the compressor 18 and the air supply pipe of the compressor 17 through the oil return line 15 and the oil return line 16, respectively.

As shown in fig. 1, the oil return line 15 is connected between the oil outlet of the oil separator 11 and the air supply port of the compressor 18. The inlet of the oil separator 11 is connected with the exhaust port end of the compressor 17, receives the oil-gas mixture discharged by the compressor 17 and separates the oil-gas mixture; an oil return line 16 is connected between the oil outlet of the oil separator 12 and the air supply port of the compressor 17 for delivering the oil separated by the oil separator 12 to the compressor 17. The air conditioner also comprises a controller (not shown in figure 2) which is used for acquiring the air supplementing superheat degree of the compressor (the first compressor and/or the second compressor); when the air supply superheat degree of the compressor is larger than a first preset value, if the air supply superheat degree of the compressor 17 is larger than the first preset value, the opening degree of an expansion valve 111 in an air supply loop of the compressor 17 is controlled to be reduced, if the air supply superheat degree of the compressor 18 is larger than the first preset value, the opening degree of an expansion valve 112 in the air supply loop of the compressor 18 is controlled to be reduced, if the air supply superheat degree of the compressor 17 is smaller than a second preset value, the opening degree of the expansion valve 111 in the air supply loop of the compressor 17 is controlled to be increased, if the air supply superheat degree of the compressor 18 is smaller than the second preset value, the opening degree of an expansion valve 112 in the air supply loop of the compressor 18 is controlled to be increased, the air supply superheat degrees of the compressor 17 and the compressor 18 in the air conditioner are continuously detected, and the opening degrees of the expansion valve 111 and the expansion valve 112 in the air supply loops of the compressor 17 and the compressor 18 are, until the air-supply superheat degree of the compressor 17 and the compressor 18 is not greater than the first preset value and not less than the second preset value, wherein the expansion valve 111 and the expansion valve 112 may be electronic expansion valves, and the oil return line 15 and the oil return line 16 may be capillary tubes.

Further, in the case that the two compressors of the air conditioner in the embodiment are connected in parallel, the controller is further configured to: when the air conditioner operates in an oil return mode, the two compressors are controlled to operate together, specifically, for two compressors of the air conditioner which are connected in parallel, if only one compressor operates, if an air conditioning system meets an oil return condition and enters an oil return mode, the other compressor is controlled to start, so that the two compressors can operate normally, and the situation of oil shortage can be prevented when a single compressor operates.

The embodiment also provides an air conditioner, and the air conditioner comprises any one of the air conditioner oil return systems.

In the oil return system of the air conditioner shown in fig. 1, the outdoor unit of the air conditioner has two compressors running in parallel, the two compressors are respectively provided with an independent oil separator, an oil return electromagnetic valve and an oil return pipeline, as shown in fig. 1, an oil return port of the oil separator 11 is closer to an air supply port of the compressor 18, and separated lubricating oil can preferentially return to the compressor 18; similarly, the lubricating oil separated by the oil separator 12 will preferentially return to the compressor 17, so that the oil return system can effectively exert the oil balancing function, the reliability of the operation of the compressor is increased, and the service life of the compressor is prolonged. More importantly, the system enables the lubricating oil to be returned to the compressor from the air supplementing port of the compressor, and the air supplementing flow can be properly increased by adjusting the electronic expansion valve of the air supplementing loop to be large, so that the temperature of the lubricating oil is reduced, and the system energy efficiency under the air supplementing mode is improved. Compared with the mode of directly returning oil from the air suction pipe of the compressor, the heat exchange effect of the system can be prevented from being influenced by the fact that the air suction temperature is increased due to the fact that lubricating oil is sucked from the air suction pipe.

Example 2

The present embodiment provides an oil return method for an air conditioner, which may be performed by the air conditioner provided in embodiment 1, and fig. 2 is a flowchart of the method, and as shown in fig. 2, the method includes the following processes:

step 201: when the air conditioner operates in oil return mode, the air supplement superheat degree of a compressor in the air conditioner is obtained;

the method for obtaining the superheat degree of the supplied air of the compressor in the air conditioner is already described in the above embodiment 1, and is not further described here.

Step 202: and adjusting the air supply flow in an air supply loop of the compressor according to the air supply superheat degree of the compressor so as to reduce the oil return temperature of the air conditioner.

The operation of adjusting the make-up air flow in the make-up air circuit of the compressor according to the make-up air superheat degree of the compressor in the embodiment may include: when the air supply superheat degree of the compressor is larger than a first preset value, the opening degree of an expansion valve in an air supply loop of the compressor is controlled to be reduced, and when the air supply superheat degree of the compressor is smaller than a second preset value, the opening degree of the expansion valve in the air supply loop of the compressor is controlled to be increased until the air supply superheat degree of the compressor is not larger than the first preset value and not smaller than the second preset value.

Optionally, the air conditioner in this embodiment includes a first oil separator, a first compressor, a second compressor, and a first oil return line, wherein an inlet of the first oil separator is connected to an exhaust port end of the first compressor, and the first oil return line is connected between an oil outlet of the first oil separator and an air supplement port of the second compressor.

Further, the air conditioner provided by this embodiment may further include: the inlet of the second oil separator is connected with the exhaust port end of the second compressor; and the second oil return pipeline is connected between the oil outlet of the second oil separator and the air supplementing port of the first compressor and is used for conveying the oil separated by the second oil separator to the first compressor.

Optionally, the first compressor and the second compressor in this embodiment are connected in parallel, and based on this, the method provided in this embodiment further includes: and when the air conditioner operates in an oil return mode, the first compressor and the second compressor are controlled to operate together. Specifically, for two compressors connected in parallel of the air conditioner, if only one compressor is operated, if the air conditioning system meets the oil return condition and enters the oil return operation mode, the other compressor is controlled to be started, so that the two compressors can be ensured to normally operate, and the situation of oil shortage can be prevented when a single compressor is operated.

The air conditioner oil return method provided by the present embodiment is explained by way of example below.

In one example, the air conditioner oil return method of the application comprises the following steps:

when the system operates, the air supplementing pressure Pm is acquired through a pressure sensor arranged at an air supplementing main pipe of the air conditioner, the saturation temperature Tm corresponding to the air supplementing pressure is obtained, and the air supplementing temperatures T1 and T2 are acquired through

temperature sensing bags

110 and 19.

And the air conditioning system meets the oil return condition and enters an oil return operation mode. After entering an oil return operation mode, oil return electromagnetic valves A and B are opened, and lubricating oil separated from the oil separators A and B respectively flows to a compressor air supplementing pipe after passing through oil return pipelines;

the flow of lubricant to the make-up air line causes an increase in make-up air temperature T1 or T2, which typically results in excessive make-up air superheat. The air supplementing superheat degree of the compressor A can be obtained through T1-Tm, and the air supplementing superheat degree of the compressor B can be obtained through T2-Tm. And judging whether the air supply superheat degree of the compressor is proper or not according to the obtained air supply superheat degree.

If the air supplement superheat degree of the compressor A or the compressor B is smaller, the opening degree of an electronic expansion valve of an air supplement branch corresponding to the compressor with the smaller air supplement superheat degree is reduced, and then the step of judging whether the air supplement superheat degree is proper is returned; similarly, if the air supplement superheat degree of the compressor A or the compressor B is larger, the opening degree of the electronic expansion valve of the air supplement branch corresponding to the compressor with the larger air supplement superheat degree is adjusted to be larger, and then the step of judging whether the air supplement superheat degree is proper is returned. And keeping the opening degree of the air supply electronic expansion valve corresponding to the compressor until the air supply superheat degrees of the compressor A and the compressor B are both proper.

And the system meets the oil return end condition, and the oil return is ended. And the air conditioning unit exits the oil return mode, and the oil return electromagnetic valves A and B are closed. The system resumes operation in the run mode prior to the oil return mode.

In example 1 and example 2 of the present application, an air conditioner having two compressors is described as an example, but the present invention is also applicable to oil return control of an air conditioner having three or more compressors.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. An air conditioner oil return system, characterized by comprising:

the inlet of the first oil separator is connected with the air outlet end of a compressor in the air conditioner and is used for receiving an oil-gas mixture discharged by the compressor connected with the first oil separator and separating the oil-gas mixture;

a first oil return line for transferring the oil separated by the first oil separator to a compressor in the air conditioner;

the controller is used for adjusting air supplement flow in an air supplement loop of the compressor according to air supplement superheat degree of the compressor in the air conditioner during oil return operation of the air conditioner so as to reduce oil return temperature of the air conditioner;

the air conditioner comprises a first compressor and a second compressor, and the first oil return pipeline is connected between an oil outlet of the first oil separator and an air supplementing port of the second compressor; the first compressor is connected in parallel with the second compressor, and the controller is further configured to: when the air conditioner operates in an oil return mode, the first compressor and the second compressor are controlled to operate together;

if only one compressor of the air conditioner runs, if the air conditioning system meets the oil return condition and enters the oil return running mode, the other compressor is controlled to start, and the two compressors can run normally.

2. The system of claim 1, wherein the air conditioner further comprises:

the inlet of the second oil separator is connected with the gas outlet end of the second compressor and is used for receiving the oil-gas mixture discharged by the second compressor and separating the oil-gas mixture;

and the second oil return pipeline is connected between an oil outlet of the second oil separator and an air supplementing port of the first compressor and is used for conveying the oil separated by the second oil separator to the first compressor.

3. The system of claim 1, wherein the controller adjusts the make-up air flow in the make-up air circuit of the compressor based on a make-up air superheat of the compressor in the air conditioner by:

acquiring the air supplement superheat degree of the compressor;

and when the air supplementing superheat degree of the compressor is smaller than a second preset value, controlling the opening degree of an expansion valve in the air supplementing loop of the compressor to be reduced until the air supplementing superheat degree of the compressor is not larger than the first preset value and not smaller than the second preset value.

4. An air conditioner characterized by comprising a system according to any one of claims 1 to 3.

5. An oil return method of an air conditioner is characterized by comprising the following steps:

when the air conditioner operates in an oil return mode, acquiring the air supplement superheat degree of a compressor in the air conditioner;

adjusting the air supply flow in an air supply loop of a compressor according to the air supply superheat degree of the compressor in the air conditioner so as to reduce the oil return temperature of the air conditioner;

the air conditioner comprises a first oil separator, a first compressor, a second compressor and a first oil return pipeline, wherein an inlet of the first oil separator is connected with an exhaust port end of the first compressor, and the first oil return pipeline is connected between an oil outlet of the first oil separator and an air supplementing port of the second compressor;

the first compressor is in parallel with the second compressor, the method further comprising:

when the air conditioner operates in an oil return mode, controlling the first compressor and the second compressor to operate together; if only one compressor of the air conditioner runs, if the air conditioning system meets the oil return condition and enters the oil return running mode, the other compressor is controlled to start, and the two compressors can run normally.

6. The method of claim 5, wherein the air conditioner further comprises:

the inlet of the second oil separator is connected with the gas outlet end of the second compressor;

7. The method of claim 5, wherein said adjusting the flow of make-up air in the make-up air circuit of the compressor based on the make-up air superheat of the compressor comprises: