优化控制R744多喷射器双温超市制冷系统

Control optimization of R744 duo-temperature supermarket refrigeration system with multi-ejector

为了使R744双温超市制冷系统在任何环境温度下都能以最高效率运行,在R744平行压缩制冷系统中增加了一个多喷射器组回路(包括气气喷射器和气液喷射器),以确保系统在高温环境下仍能以较高的效率运行。并在环境温度变化的情况下,通过自动控制阀切换多喷射增压制冷模式和平行压缩制冷模式,为此建立了系统的热力学模型。计算结果表明,当环境温度低于17.32℃时,采用平行压缩制冷模式;当环境温度高于17.32℃时,采用多喷射增压制冷模式。当环境温度从21.1℃变化到36℃时,多喷射器制冷系统的COP比平行压缩制冷系统高15.91%~32.61%。

In order to make the duo-temperature R744 supermarket refrigeration system operate at maximum efficiency in any ambient temperature,a multi-ejector circuit(including gas-gas ejector and gas-liquid ejector)is added to the R744 parallel compression refrigeration system to ensure that the system can still operate at higher efficiency in high ambient temperature,and automatically switch between parallel compression refrigeration mode and boost refrigeration with multi-ejector mode with the change of ambient temperature.The thermodynamic model of the system is established.The calculation results show that when the ambient temperature is lower than 17.32℃,the parallel compression refrigeration system mode is adopted;when the ambient temperature is higher than 17.32℃,the transcritical boost refrigeration system with multi-ejector mode is adopted.When the ambient temperature changes from 21.1℃to 36℃,the COP of the multi-ejector refrigeration system is 15.91%-32.61%higher than that of the parallel refrigeration system.