Absorption Refrigeration, Deep Freezing, Thermodynamic Analysis, Experiments
A novel absorption refrigeration system is proposed in this context using R134a+R23 mixed refrigerants and DMF solvent. The new system uses two-staged absorber in series to reduce the evaporation pressure and can obtain a lower refrigeration temperature by the low-grade thermal energy. From thermodynamic analysis, the key factors are discussed on the performances of the new system. Under the same working conditions, comparisons on the performances are also conducted between the new one and an auto-cascade absorption refrigeration system with single-absorber. Experiments are conducted to investigate the key effecting factors on the performances of the new system and a single-absorber auto-cascade absorption refrigeration system. The experimental results show that the new system can achieve a lower refrigeration temperature under the same working condition. The lowest refrigeration temperature of the new system reaches to -62.3℃ with a COP of 0.023 under a generation temperature of 184.4℃, condensing temperature of 18.8℃, and absorption temperatures of 26.4℃ at the low-pressure absorber, and 28.5℃ at the high-pressure absorber.