Solar heat accumulation type two-stage compressed air source heat pump system and operation method thereof

Abstract

The invention relates to the field of heat pumps, in particular to a solar heat accumulation type two-stage compressed air source heat pump system. The system comprises two variable-capability compressors, two outdoor heat exchangers, a flash vessel, an electronic expansion valve and a heat accumulation water tank. The system is characterized in that the system is in a refrigeration operation mode and a heating operation mode, an independent compressed operation way, a parallel connection compressed operation way and a two-stage compressed operation way are achieved in the two operation modes, the two outdoor heat exchangers in the system are arranged in parallel, an interstage hot gas bypass loop and a solar heat accumulation device are arranged to be matched with an electromagnetic valve and a one-way valve, and defrost circulation of continuous heating is formed. The solar heat accumulation type two-stage compressed air source heat pump system has the beneficial effects that the compressor capacity can be adjusted in the refrigeration, heating and defrosting process, a refrigerant is made to overheat through the solar heat accumulation device, the outdoor heat exchangers are arranged in parallel for alternate defrosting, and therefore the system provides heat for the interior of a room stably in cold climates. The system is used in a habitable room in the cold region, and has the wide application and popularization space and the energy-saving significance.

Description

technical field [0001] The invention belongs to the field of heat pumps, in particular to a solar heat storage type two-stage compressed air source heat pump system and its operating method. Background technique [0002] When the existing air source heat pump operates in a low temperature environment, there are problems such as a sharp decrease in heating capacity and an excessively high exhaust temperature of the compressor; at the same time, when the ambient temperature is lower than 0°C, a large area will appear on the surface of the outdoor heat exchanger. The frosting phenomenon will lead to the decrease of the heat exchange performance of the outdoor heat exchange equipment, and have a great impact on the comprehensive heating performance of the heat pump device. At present, variable capacity and (quasi) two-stage compression technologies are often used to improve the heating capacity of air source heat pumps in low temperature environments. Among them, the variable c...

AI Technical Summary

Problems solved by technology

For the two-stage heat pump compression system, if reverse defrosting is adopted, the pressure of the high-pressure stage, middle stage and low-pressure stage changes greatly before and after the system defrosting, resulting in a longer period for the system to restore stable operation. The system stability in the frosting process is poor, so reverse defrosting is difficult to apply to two-stage compression systems; for hot gas bypass defrosting, two-stage heat pump compression heat pump systems usually use high-pressure stage compressor exhaust bypass defrosting, this method defrosting The frosting process not only affects the indoor temperature and the thermal comfort of the human body, but also the system heating performance coefficient is low; at the same time, during the defrosting process, it is difficult to adjust the capacity of the system's high and low pressure compressors reasonably

In addition, when the defrosting of the system ends, the refrigerant in the bypass circuit of the defrosting cycle flows directly from the outdoor heat exchanger into the suction port of the low-pressure compressor. As a result, a large amount of liquid refrigerant enters the compressor, causing great damage to the compressor; in addition, solar water heaters have been widely used in households as equipment for providing domestic hot water, but they have a single purpose and have not yet fully utilized their functions

So far, there are no literature reports and practical applications on the solar thermal storage type two-stage compressed air source heat pump system and its operation method

Images