CO2 mixed working medium and CO2 mixed working medium heat pump system

Abstract

The invention discloses a CO2 mixed working medium and a CO2 mixed working medium heat pump system. The CO2 mixed working medium is formed by mixing CO2 and R290. A proper CO2 mass percent is selectedaccording to different water outlet temperatures required by actual working conditions and the function relational expression of the mass fraction x of CO2 and the water outlet temperature of an aircooler, wherein the function relational expression satisfies the condition that x equals to 0.0115Tgas-0.2178. The exhaust pressure of a compressor can be adjusted according to the function relationalexpression of the optimal pressure value Popt of the compressor, an outlet temperature T of a refrigerant in the air cooler and the mass fraction x of CO2 in the CO2 mixed working medium, wherein thefunction relational expression satisfies the condition that Popt equals to -7.74+17.55x-7.766x<2>+0.2366T-0.0009499T<2>. Therefore, the compressor always works at the optimal exhaust pressure corresponding to the optimal COP. Compared with an original pure CO2 refrigerating working medium, a heat pump air conditioning system using the CO2 mixed working medium is lower in work pressure and betterin performance, the problems that the durability of the compressor is reduced due to the excessively high work pressure of the system, the design process difficulty of pipelines and heat exchangers istoo high, and high-pressure explosions are caused are relieved to a certain extent, and the development of electric automobile air conditioning systems is promoted.

Description

technical field [0001] The invention belongs to the technical field of thermal system working medium and heat pump, and particularly relates to a CO 2 Mixed working fluid and CO 2 Mixed working fluid heat pump 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 are very suitable for water temperature heating, making it have incomparable advantages in the application field of heat pump water heaters compared to other known working fluids. [0003] However, for the use of CO 2 The heat pump air conditio...

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Problems solved by technology

[0003] However, for the use of CO 2 The heat pump air conditioning system, the system working pressure is too high has been hindered CO 2 One of the most important factors for the popularity of heat pump air conditioning systems

Excessive working pressure of the system will reduce the service life and durability of the compressor. Excessive working pressure is a huge challenge to the system equipment. cost; at the same time, a certain risk of explosion caused by high working pressure makes people pay attention to CO 2 The application of heat pump air conditioning system is prohibitive

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