Experimental Study On Three Cascade Refrigeration System Performance Matching

At present, cascade type refrigerator has been widely used due to special demand. Low temp- erature applications involving: aerospace industry simulation environment, low-temperature reliable test of electronic components and metal products, The metallurgical products quenching and tempering, preservation organ transplant, blood in medical and pharmaceutical sectors chemical products production and purification field, etc. Cascade refrigeration circulation has higher aspiratory pressure, higher compressor efficiency and lower the evaporation temperature compared with double compressing refrigeration circulation. Therefore, cascade refrigeration has higher application value in below the -60℃evaporation temperature, it is very promising. The research and application of cascade type refrigerator in China is just start, the study focuses on working performance of azeotropic refrigerants and natural refrigerants. It is valuable to research matching of classic cascade refrigeration circulation system, in order to obtain higher refrigeration coefficient.Based on the cascade refrigeration system, adopts R404A, R23, R14 refrigerants, this paper studied the theoretical analysis and experimental research. Research mainly in the following aspects:1. Analyzed the performance of the system hold that R404A/R23/R14 cascade refrigeration system has the optimal middle temperature, namely, the temperature is the best when three compressor compression ratios are roughly equivalent. And the cop is highest.2. In -60℃~-80℃interval, refrigeration coefficient of R404A/R23 is obviously higher than R404A/R23/R14.3. R404A/R13/R14 refrigeration coefficient is the highest when temperature of cold is -95℃during it drop from -85℃to-110℃, In the refrigerator temperature for -110℃, R404A/R508B /R14, R404A/R508A/R14, R404A/R503/R14, R404A/R23/R14, R404A/R13/R14 refrigeration coefficient in lower. So, R404A/R508B/R14, R404A/R508A/R14 is more suitable for triple cascade systems of refrigerant. 4. In -60℃~-110℃temperature fall process, R404A/R23/R14 cascade refrigeration system performance coefficient increases at first and then decreases, in -80℃~-85℃reach maximum.The study also found some problems in the experiment and it has yet to be further improved in subsequent research work.