Air source carbon dioxide heat pump water heater

Abstract

The invention discloses an air source carbon dioxide heat pump water heater. The heater comprises a compressor, a vortex tube, a heat exchanger, an evaporator, an expansion valve and valves, wherein an outlet of the compressor is communicated with an inlet of the heat exchanger by a first branch and an inlet of the vortex tube by a second branch respectively; the first and second branches are provided with the first and second valves respectively; the hot end branch of the vortex tube is communicated with the inlet of the heat exchanger, and the cold end branch of the vortex tube is communicated with the middle part of the heat exchanger; the outlet branch of the heat exchanger is communicated with an inlet of the evaporator and provided with the expansion valve; and the outlet branch of the evaporator is communicated with an inlet of the compressor. The carbon dioxide gas at a higher temperature can be obtained by taking the carbon dioxide as a working medium and using the vortex tube effect, so the heat exchange temperature difference between the carbon dioxide gas and water is increased to obtain hot water and boiled water as required; therefore, the water heater has the advantages of flexible operation and convenient use.

Description

technical field [0001] The invention relates to a water heater, in particular to a carbon dioxide heat pump water heater which uses carbon dioxide as a working medium and can provide boiled water or hot water, and belongs to the technical field of heating devices. Background technique [0002] Heat pump water heaters can use low-temperature heat sources to heat water and have good economics. This technology is developing rapidly and gradually being recognized by people. At present, the common heat pump water heaters on the market all use conventional freon working fluid. The problem is that in addition to causing ozone layer destruction and greenhouse effect, the water temperature is also low. In the occasions where high temperature water or boiling water needs to be provided, the thermal power of the conventional working fluid is used. The cycle performance decreases rapidly. Due to the limitation of the critical temperature of some working fluids, it is difficult for the o...

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Problems solved by technology

Common heat pump water heaters currently on the market use conventional freon working fluid. The problem is that in addition to causing ozone layer damage and greenhouse effect, the water supply temperature is also low. When high temperature water or boiling water needs to be provided, the heat of conventional working fluid should be used. The cycle performance decreases rapidly. Due to the limitation of the critical temperature of some working fluids, it is difficult for the outlet water temperature of the heat pump water heater to reach the required temperature. When the ambient temperature of the evaporator is too low, the efficiency of the unit drops sharply, and the outlet water temperature of the water heater even less than the requirements

Compared with heat pump water heaters using conventional refrigerants, the main disadvantage of carbon dioxide heat pump water heaters is the low coefficient of performance of the system, mainly because carbon dioxide heat pumps operate under transcritical conditions, and the high pressure part will reach 9MPa or higher, high pressure carbon dioxide The pressure drop of the gas through the throttling device is very high, and the throttling loss is very large. Although the efficiency of the system is improved by using the expander instead of the expansion valve, the structure of the expander is complicated and the cost is high.

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