NING Jinghong, LIU Shengchun. Performance analysis on R744 direct contact condensation refrigeration cycle[J]. CIESC Journal, 2018, (5): 2049-2056.
DOI:
NING Jinghong, LIU Shengchun. Performance analysis on R744 direct contact condensation refrigeration cycle[J]. CIESC Journal, 2018, (5): 2049-2056.DOI: 10.11949/j.issn.0438-1157.20171246.
Performance analysis on R744 direct contact condensation refrigeration cycle
The performances of R717/R744-DCC refrigeration cycle
the R744 gas discharged from R744 compressor contacts directly with the R744 super-cooled liquid provided auxiliary super cooling by R717 refrigeration cycle
are analyzed. The following conclusions are obtained. The optimum condensing temperatures of R744 main cycle exist in the R717/R744-DCC refrigeration cycle
and at the optimum condensation temperatures
the maximum coefficient of performance and minimum R717 condenser heat load are obtained. With the increasing of super cooling degree of R744 main cycle supercooled liquid
the maximum coefficient of performance reduces
the minimum R717 condenser heat load increases
the condensation temperatures of R744 main cycle increases
and the refrigerant mass flow rate of R744 evaporator decreases. Meanwhile
compared with that of R717/R744 cascade refrigeration cycle
at the same operating conditions and the optimum R744 main cycle condensing temperatures
the maximum coefficient of performance of R717/R744-DCC cycle increases 5.2%
and the minimum R717 condenser heat load reduces 1.6%. Furthermore
in the range of -10-8℃ condensation temperatures of R744 main cycle
the mass flow rate of R744 evaporator of R717/R744-DCC refrigeration cycle reduces 1.75%-2.61%
and the mass flow rate of R717 condenser of R717/R744-DCC refrigeration cycle reduces about 0.51%-0.82%.