Abstract
Cascade refrigeration system is an attractive technology for low-temperature requirement, allowing operation under these conditions with positive suction pressures and a moderate condensation pressure at ambient temperature. This work describes a performance analysis of a cascade refrigeration prototype equipped with hermetic compressors working with R-134a and R-404a as refrigerants, thermally connected by a tube-in-tube-type cascade-condenser. Energy flows and performance parameters were evaluated under different evaporating temperature conditions of the low temperature cycle (LTC). The results showed an increase in energy efficiency ratio (EER) and coefficients of performance (COP) of cascade system as well as of each cycle with the increase of LTC evaporating temperature, even with a simultaneous increase of temperature difference in cascade-condenser.
Highlights
Refrigeration systems are very important in many commercial and industrial applications as well as human life
EXPERIMENTAL EVALUATION OF A CASCADE REFRIGERATION SYSTEM USING R-134a AND R-404a Vitor Pinheiro Ferreira, Micael Lima Conceição, William Souza dos Santos under evaporating temperature below -35 oC single-stage systems working with traditional refrigerants are insufficient, showing negative suction pressure which could allow well marked oil drag through the discharge pipe and lead to air leakage into the system (DOPAZO; FERNANDEZ-SEARA, 2011)
They found that the cascade system showed lower annual energy consumption, lower refrigerant charge and lower global warming potential (GWP) than others configurations
Summary
Refrigeration systems are very important in many commercial and industrial applications as well as human life. With the increase of compression ratio, compressor volumetric efficiency and COP will be drastically reduced (ALHAMID et al, 2010) At such conditions, cascade refrigeration systems is a convenient option, allowing refrigeration in conditions of very-low evaporating temperature as in cryopreservation, rapid freezing and natural gas liquefaction applications (YOON et al, 2013). The authors conduced the analysis on semi-hermetic compressor racks connected to cold rooms and displays at similar conditions verified in commercial refrigeration They found that the cascade system showed lower annual energy consumption, lower refrigerant charge and lower global warming potential (GWP) than others configurations. Refrigerants with high critical point and positive evaporating pressure under low-temperature conditions can be used in the cascade LTC (SUN et al, 2016; DU et al, 2009; KILICARSLAN; HOSOZ, 2010). The system can be applied in small refrigeration applications if low evaporating temperature is required
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
