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Oil return control method of direct expansion type earth source heat pump

A ground source heat pump, oil return control technology, applied in heat pumps, refrigerators, refrigeration components, etc., can solve problems such as affecting system operation, accumulation of lubricating oil in underground heat exchanger pipelines, and inability to ensure complete oil return, and achieve guaranteed Oil return efficiency, good effect and good accuracy

Inactive Publication Date: 2009-12-09
HUNAN UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

However, the usual oil return measures cannot guarantee complete oil return, and lubricating oil may still accumulate at the bottom of the underground heat exchanger pipeline, which will affect the system operation

Method used

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  • Oil return control method of direct expansion type earth source heat pump
  • Oil return control method of direct expansion type earth source heat pump

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Embodiment Construction

[0027] figure 1 is the direct expansion ground source heat pump system diagram, where A 1 、A 2 , ..., A, are all underground heat exchangers; electromagnetic valves are installed at the entrances of each underground heat exchanger, followed by B 1 , B 2 ,...,B N , each solenoid valve is connected with the controller 15, and the differential pressure sensor 16 is installed at the inlet and outlet of the underground heat exchanger, and the differential pressure sensor 16 is connected with the controller 15.

[0028] In the oil return control method of the direct expansion ground source heat pump of the present invention, under the condition that the total refrigerant flow rate is constant, the electromagnetic valves of the branch pipelines of some underground heat exchangers are closed to reduce the number of pipelines of the underground heat exchangers in actual operation. Increase the flow rate of the refrigerant, and use the high-speed flowing refrigerant to bring the lub...

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Abstract

The invention relates to an oil return control method of a direct expansion ground source heat pump. The method comprises: monitoring the pressure difference between the inlet and outlet of the pipeline of the underground heat exchanger group of the direct expansion ground source heat pump in real time, and judging the underground heat transfer through the change of the pressure difference Whether there is lubricating oil accumulation and blockage in the pipeline of the heat exchanger. When the lubricating oil accumulation occurs in the pipeline of the underground heat exchanger or the continuous normal operation of the system exceeds the preset time, some underground pipelines will be closed in sequence for a certain period of time to improve the quality of the remaining underground pipelines. The refrigerant flow rate is high, and the high-speed flowing refrigerant will bring the lubricating oil accumulated in the blocked buried copper pipe back to the compressor, so as to realize the smooth oil return of the system. The oil return control method of the invention can effectively improve the oil return efficiency of the system, improve the operation stability of the system, avoid failure of the compressor due to lack of oil, and ensure the efficient operation of the direct expansion ground source heat pump system.

Description

technical field [0001] The invention relates to ground source heat pump technology, in particular to an oil return control method of a direct expansion ground source heat pump. Background technique [0002] Direct expansion ground source heat pump is an advanced technology that can more efficiently utilize low-grade heat energy in shallow surface soil. Compared with traditional ground source heat pumps, it directly charges refrigerant in the underground heat exchanger pipeline, reducing In the intermediate heat exchange link, the system efficiency is improved, and there is no danger of freezing, and there is no need to add antifreeze; at the same time, due to the reduction of intermediate heat exchange pipelines, the consumption of pipes is relatively reduced, and the amount of underground construction is also relatively reduced. Direct expansion ground source heat pumps are mainly used in small systems, so the number of buried pipes is relatively small, generally no more th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F25B49/02F25B30/06
Inventor 张国强杨伟周晋林汉柱
Owner HUNAN UNIV