B. Karthikeyan
CO2 Research and Green Technologies Centre, Vellore Institute of Technology, Vellore-632014, India
Rajagopal Saravanan
R&AC Division, Department of Mechanical Engineering, College of Engineering, Guindy, Anna University, Chennai-600 025, India
G. Praveen Kumar
CO2 Research and Green Technologies Centre, Vellore Institute of Technology, Vellore-632014, India
The need of heating and cooling is of more importance for many typical applications such as hotel, agriculture and dairy industry etc. Cascading refrigeration can able to provide both heating and cooling in an efficient way. This study compares performance of cascade vapor compression (CX) and cascade liquid suction heat exchanger (CLSHX) system to generate combine heating and cooling using natural refrigerants. The
natural refrigerant pairs of R744 − R717, R744 −
R1270, R170 − R717 and R170 − R1270 has been
selected for this study. R744 − R1270 and R170 −
R1270 refrigerant pair was suitable to the CLSHX system on other hand R744 − R717 and R170 − R717 was not favorable selection to the CLSHX system. The parametric study is carried to sort out refrigerant pair for both CX and CLSHX system by varying evaporating, condensing and in-between cascade heat exchanger (CHX) temperature. The parametric studies shows that combined COP of R744 − R1270 and R170
− R1270 refrigerant pair was increased in the range
from 5.1% to 5.5% for a CLSHX system. Exergy destruction rate was more at higher compressor and higher expansion valve with 31.61% and 29.45% respectively in a CX system, whereas in the CLSHX system, higher expansion valve exergy destruction is about 10.99%. Efficient utilization of CLSHX system attained by proper design and selection of higher condenser and CHX.