DEVELOPMENT OF COMPACT INVERTER REFRIGERATING SYSTEM USING R600a/ CO_2 BY 'THERMO SIPHON'

摘要

In Japan, "energy saving" is inevitable now and high-efficiency commercial refrigerators with inverterrncompressors are getting popular using fluorocarbon. But fluorocarbon-free refrigerators are demanded tornreduce GWP.rnWe developed a compact inverter refrigerating system with an inverter compressor using R600a for thernprimary refrigerant and CO_2 by "thermo siphon" for the secondary refrigerant. We successfully limited thernrefrigerant volume to 40 grams of R600a and 100 grams of CO_2 by applying the condenser and evaporatorrnwith spiral finned small diameter tubes and by the R600a/CO_2 heat exchanger for CO_2 pre-cooling. As arnresult, we could eliminate the CO_2 expansion tank and realize the compact, cost-saving system.rnWe secured the safety by preventing leakage of flammable gas inside the chamber and by minimizing thernrefrigerant volume of R600a. We realized energy saving of 5% against our own inverter refrigerating systemrnwith 280 grams of R134a when equipped in a 1000-liter refrigerator.