Carbon dioxide system for parallel flow evaporator and operating method of carbon dioxide system

Abstract

The invention discloses a carbon dioxide system for a parallel flow evaporator. The carbon dioxide system includes a compressor, a gas cooler, an intermediate heat exchanger, an electronic expansion valve, a liquid storing device and the evaporator, a gas exhausting opening of the compressor is connected with an inlet of the gas cooler, an outlet of the gas cooler is connected with an a-end inletof the intermediate heat exchanger, a b-end outlet of the intermediate heat exchanger is connected to an inlet of the electronic expansion valve, and an outlet of the electronic expansion valve is connected with an inlet of the liquid storing device; and a gas outlet of the liquid storing device is connected with a c-end inlet of the intermediate heat exchanger, a d-end outlet of the intermediateheat exchanger is connected with an outlet of the evaporator, a liquid outlet of the liquid storing device is connected with an inlet of the evaporator, and an outlet of the evaporator is connected with a gas sucking opening of the compressor. The carbon dioxide system can regulate the gas and liquid flow and dryness of a refrigerant entering the parallel flow evaporator, improves the heat exchange performance of the parallel flow evaporator, improves the cycle performance of trans-critical cycle accordingly, and solves the problem that the heat transfer performance is significantly reduced due to the uneven distribution of gas and liquid phases between flat tubes in the parallel flow evaporator.

Description

technical field [0001] The invention belongs to the field of transcritical carbon dioxide systems, in particular to a parallel flow evaporator carbon dioxide system. Background technique [0002] As we all know, synthetic refrigerants such as CFCs and HCFCs are one of the main factors leading to global warming. Therefore, finding and using efficient, green and environmentally friendly refrigerants has become a common concern of the international community and is urgent. Natural working fluid CO 2 As an alternative working fluid, it is not only environmentally friendly but also has excellent performance. The high exhaust temperature and temperature glide of its transcritical cycle make it have incomparable advantages in the application field of heat pump water heaters compared with other known working fluids. G Lorentzen, former president of the International Institute of Refrigeration, proposed the CO 2 The transcritical cycle theory points out that it will have extremely ...

AI Technical Summary

Problems solved by technology

The distribution of the gas-liquid two phases (especially the liquid phase) among the flat tubes in the parallel flow evaporator has a great influence on its heat transfer performance. If the gas-liquid distribution between the flat tubes is uneven, the heat transfer performance will be significantly reduced. , if the pure liquid refrigerant enters the parallel flow evaporator, the liquid separation in the evaporator is uniform, and the heat transfer efficiency is good; It affects the heat exchange effect of the heat exchanger and reduces the cycle performance of the system

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