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

Abstract

The invention discloses a low-temperature heat pump circulation system and a circulation method suitable for a large temperature span. The system uses two compressors, a low-pressure side compressor and a high-pressure side compressor; the exhaust gas of the high and low pressure compressors forms two different condensation temperatures, Meet the heating demand of large temperature span. The cycle can be operated independently through the dual compressors, and the two separate systems are coupled through the ejector to improve the reliability of the system operation, and realize the large temperature span heating through the gradient heating at the double condensing temperature; at the same time, through the ejector , can increase the suction pressure of the low-pressure side compressor, and control the suction pressure of the high-pressure side compressor through intermediate flashing, thereby reducing the pressure ratio of the dual compressors, adapting to the operation at low ambient temperature, and improving the overall performance of the system; in addition , due to the pressure increase of the ejector, the evaporation temperature of the two evaporators is different, which reduces the irreversible loss of the heat transfer process between the refrigerant and the heat source, and further improves the system performance.

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

Images