Thermodynamic analysis of refrigerants pairs in two stages cascade vapor compression refrigeration cycle for cooling of telecommunications equipment with volume decreasing approach

In this research a two-stage cascade refrigeration cycle with different refrigerants thermodynamically is analyzed and then every component of cycle with the approach to achieve the volume less is studied. Functional variables are including evaporation temperature, pressure ratio and the amount of input work in both high and low temperature cycle and cooling capacity as stated in issue is considered. With the change of refrigerants in high and low temperature circuits, variation the volume of the components and change the coefficient of performance of the system is investigated. The results show that the lowest volume of the system with refrigerant R-134a use in high temperature cycle and R-508B and R- 23 in low temperature cycle archives and the total volume of system reduce. It is observed that at low evaporation temperatures the compressor volume is highly dependent on the amount of cooling capacity. As for the evaporation temperature 173K, with increasing of cooling capacity from 100W to 200 W, the compressor volume from 9100 cm3 to 3.2 times increases. It is also seen with increasing the evaporation temperature, the volume of air cooled condenser volume of condenser reduces and it is observed that in the evaporation temperature 173K, with increasing of cooling capacity from 100 W to 200 W, the volume of air cooled condenser system in two-stage cascade increases from 4500 cm3 to 13000 cm3.