Carbon dioxide heat pump circulation loop

Abstract

The invention belongs to the field of air energy heat pumps or air energy water heaters, and particularly relates to a carbon dioxide heat pump circulation loop which comprises a compressor, a water cooling heat exchanger, a double-tube heat exchanger, a throttling device and an evaporator. An outlet of the compressor, a refrigerant tube of the water cooling heat exchanger, a tube pass of the double-tube heat exchanger, the throttling device, the evaporator, a shell pass of the double-tube heat exchanger and an inlet of the compressor are sequentially connected, carbon dioxide refrigerants of the water cooling heat exchanger are led into the double-tube heat exchanger, low-temperature carbon dioxide gas at an outlet of the evaporator is led into the shell pass of the double-tube heat exchanger and used for cooling the carbon dioxide refrigerants in the tube pass, the carbon dioxide refrigerants are liquefied, and the liquefied carbon dioxide refrigerants enter the throttling device and enter the inside of the evaporator after throttling pressure reduction, so that circulation of the carbon dioxide heat pump circulation loop is realized.

Description

technical field [0001] The invention belongs to the field of air energy heat pumps or air energy water heaters, in particular to a carbon dioxide heat pump circulation loop. Background technique [0002] Heat pump technology has developed rapidly in recent years, especially in northern China, it is the general trend to replace traditional coal-fired heating with air source heat pumps. At present, most of the heat pump compressors use R22, R410a and other refrigerants. Under the low temperature environment (-25°C), such compressors not only need to use gas injection to increase enthalpy or liquid injection technology to ensure sufficient exhaust temperature for heating or hot water. use, and not environmentally friendly. Carbon dioxide refrigerant is currently the most environmentally friendly refrigerant known in the world, and its physical properties are also one of the most suitable refrigerants for low-temperature heat pump systems. Carbon dioxide refrigerant has a low e...

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Problems solved by technology

However, as a refrigerant, carbon dioxide has a low critical temperature (31°C), and the system needs to work in a supercritical state. Under normal circumstances, it is difficult for a water cooler to directly cool the high-temperature and high-pressure carbon dioxide refrigerant into a liquid state. The use of low-temperature cooling water (below 31°C) can condense high-temperature and high-pressure carbon dioxide refrigerant into a liquid state, but the temperature of heat pump cooling water or circulating water and the ambient temperature cannot ensure that it is lower than the critical temperature of carbon dioxide refrigerant throughout the year

Therefore, the water cooler cannot ensure that the carbon dioxide refrigerant can be condensed into a liquid state under any circumstances, and if the carbon dioxide refrigerant is not condensed into a liquid state before entering the throttling device, the purpose of throttling evaporation cannot be achieved

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