双级压缩制冷系统模拟研究

Simulation study on two-stage compression refrigeration system

温度变化对系统制冷系数和高低压级压缩机输气量都有较大影响,变频压缩机能够根据温度变化调整频率,改变压缩机输气量,达到节能目的。为验证温度变化对双级压缩制冷系统的影响,建立一次节流中间不完全冷却循环的热力学模拟。结果表明:中间温度为4℃时,高低压级输气量之比为1∶0. 55,系统制冷系数取得最大值为3. 726。在该实验工况下,平均蒸发温度每升高1℃,高低压级理论输气量之比升高0. 8%;平均冷凝温度每升高1℃,高低压级理论输气量之比降低0. 5%。蒸发温度对制冷系数的影响大于冷凝温度对制冷系数的影响。

Temperature change of the refrigeration system has great influence on refrigeration coefficient and the input gas of high and low pressure compressor. Frequency conversion compressor can be adjusted according to the temperature change, and it will change the compressor capacity to achieve energy saving. In order to verify the influence of temperature change on the two - stage compression refrigeration system, a thermodynamic simulation of incomplete cooling cycle in the middle of a throttling was established. Results show that the ratio of input gas of high and low pressure is 1 to 0.55 and the system obtains the maximum re- frigeration coefficient of 3. 726 in the middle temperature of 4℃. Under this experimental condition, the ratio of input gas of high and low pressure increases by 0. 8% when the average evaporation temperature rises every 1 ℃ ,and the ratio of input gas of high and low pressure reduces by 0.5% when the average condensation temperature rises every 1 ℃. The effect of evaporation tempera- ture on the refrigeration coefficient is greater than that of condensation temperature.