Low-temperature heat pump circulation system suitable for large temperature span and circulation method

Abstract

The invention discloses a low-temperature heat pump circulation system suitable for large temperature span and a circulation method. The system uses two compressors, namely the low-pressure side compressor and the high-pressure side compressor; exhaust of the high and low pressure compressors forms two different condensation temperatures, and the requirement for large-temperature-span heat supplyis met; the circulation can be independently operated through the two compressors, two independent systems are coupled through an ejector, the operation reliability of the systems is improved, and thelarge-temperature-span heat supply is achieved through gradient heating at the double condensation temperatures; meanwhile, through the ejector, the air suction pressure of the low-pressure side compressor can be improved, the air suction pressure of the high-pressure side compressor is controlled through middle flash evaporation, and therefore the pressure ratio of the two compressors is reduced, the operation at the low environment temperature is adapted, and the overall performance of the system is improved; and in addition, due to the fact that the evaporation temperatures of two evaporators are different due to the pressure increasing effect of the ejector, irreversible losses in the heat transfer process between a refrigerant and a heat source are reduced, and the system performanceis improved.

Description

technical field [0001] The invention belongs to the technical field of vapor compression heat pumps, and in particular relates to a low-temperature heat pump circulation system and a circulation method suitable for a large temperature span. [0002] technical background [0003] With the increasingly serious environmental problems, improving energy utilization and reducing environmental problems in the process of energy utilization is one of the major concerns in the world today. As a high-efficiency energy-saving device that makes full use of low-grade heat energy, heat pump is one of the new energy technologies that has attracted much attention in the world at this stage. In recent years, with the advancement of my country's clean energy reform, heat pump technology has developed rapidly, especially in the cold northern regions. At present, with the continuous development and progress of science and technology, the demand for high heating temperature and large temperature ...

AI Technical Summary

Problems solved by technology

[0004] Under the low-temperature working conditions of traditional single-stage compression heat pumps, there will be serious heat load attenuation, insufficient heating temperature, and excessive compressor pressure ratio, which will reduce compressor efficiency and severely limit the use of heat pumps in cold regions.

In addition, traditional heat pump technology requires the system to operate at a higher condensing temperature and pressure when faced with high heating temperature, which will lead to an increase in the compressor pressure ratio and a decrease in system reliability; , Excessive heat transfer temperature difference of the condenser will also increase the irreversible loss of heat transfer and reduce the overall performance of the system

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