Air Conditioner Oil Return Cooling for Lower Compressor Suction Temperature
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Solution Overview
Problem
In air-conditioners with multiple indoor units, directly returning low-pressure high-temperature refrigerant oil and gas to the compressor suction side leads to increased suction temperature, reduced refrigerant density, and decreased compressor performance, resulting in higher power consumption and motor wiring temperature issues.
Innovation Solution
The air-conditioner design includes an oil separator that separates high-pressure high-temperature gas refrigerant and oil, which are then routed through a heat source side heat exchanger to release heat before being returned to the compressor suction side, reducing suction temperature and improving refrigerant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-pressure high-temperature refrigerator oil and gas refrigerant are directly returned to the compressor suction side, then the refrigerator oil is quickly returned to the compressor, but the suction temperature increases and refrigerant density decreases
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the oil separator and the compressor suction side. The heat exchanger allows the high-pressure high-temperature gas refrigerant to release heat to the surrounding environment or to another refrigerant stream, cooling it down before it mixes with the refrigerator oil and enters the compressor. This mediator resolves the contradiction by providing a pathway to cool the refrigerant-oil mixture without delaying its return to the compressor.
Solution Approach 2:
The invention changes the temperature parameter of the gas refrigerant by forcing it to pass through a heat exchanger where heat transfer occurs. The high-pressure high-temperature gas refrigerant undergoes cooling, transforming its thermal state from high-temperature to low-temperature condition before entering the compressor suction side, thus resolving the temperature increase issue while maintaining the quick return of oil.
2Reliability
If low-pressure high-temperature refrigerator oil and gas refrigerant are directly returned to the compressor suction side, then the oil return is rapid, but the refrigerant circulation amount decreases
Solution Approach 1:
The heat exchanger serves as an intermediary that cools the refrigerant-oil mixture without significantly increasing the pressure drop or flow resistance. By cooling the refrigerant in the heat exchanger rather than directly in the suction line, the system maintains better refrigerant density and circulation amount while still achieving rapid oil return to the compressor.
3Reliability
If low-pressure high-temperature refrigerator oil and gas refrigerant are directly returned to the compressor suction side, then the oil return is quick, but power consumption increases
Solution Approach 1:
By changing the temperature parameter of the gas refrigerant through heat exchange before it enters the compressor, the refrigerant density is improved. This allows the compressor to operate more efficiently with better suction conditions, reducing the power consumption required to achieve the same refrigeration effect while maintaining rapid oil return.
Solution Approach 2:
The invention converts the harmful high-temperature condition of the gas refrigerant into a beneficial cooling process. The high-pressure high-temperature gas refrigerant, which would normally cause problems, is deliberately passed through a heat exchanger to release its heat, and this heat release process is used to cool the refrigerant-oil mixture, improving compressor suction conditions and reducing power consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach suppresses the increase in compressor suction and discharge temperatures, enhancing compressor reliability and performance by maintaining optimal refrigerant density and circulation, thus reducing power consumption and motor wiring temperature.
Implementation Method 1
routed through a heat source side heat exchanger to release heat before being returned to the compressor suction side
Data Source
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AI summary
An air-conditioner capable of suppressing increase in the suction temperature of a compressor is provided. The air-condrtioner 100 according to the present invention has a refrigerant circuit in which a compressor 1, an oil separator 2, a heat source side heat exchanger 4, a throttle device 102, and a use side heat exchanger 101 are connected in series, an oil returning circuit 31 that connects the oil separator 2 with the suction side of the compressor 1, and a decompression mechanism 11 provided in the oil return circuit 31. The oil return circuit 31 is installed by piping so as to exchange heat with a part of the heat source side heat exchanger 4 at the upstream side of the decompression mechanism 11.