Abstract:

A thermochemical sorption deep-freezing system using manganese chloride-ammonia as sorption working pair was designed.For this test unit，expanded graphite was used as the porous medium of the reactant to improve the mass transfer inside the composite sorbent，and the consolidation technology was utilized to enhance the heat transfer performance.Experimental results showed that the additives of expanded graphite can avoid the agglomeration and the attenuation of sorption capacity.The consolidated composite sorbent could uptake 0.47 kg NH₃•（kg salt）^-1.The chemical reaction between the composite sorbent and the refrigerant has a strong influence on the temperature evolution inside the reactor，and the sorption platforms were dissimilar at different evaporation temperatures.The lower the evaporation temperature，the lower the reactive rate.The specific cooling power（SCP）varied between 206 W•kg^-1 and 706 W•kg^-1 when the evaporation temperature ranged from-35℃ to 0℃.For the thermochemical sorption deep-freezing system，SCP and coefficient of performance（COP）obtained with the consolidated composite sorbent were as high as 350 W•kg^-1 and 0.34 respectively，at the cooling water temperature of 25℃ and the evaporation temperature of -30℃.

摘要：

设计了一种以氯化锰-氨为吸附工质对的热化学吸附式低温冷冻系统，利用膨胀石墨的多孔特性作为复合反应物的添加剂来提高吸附剂的传质性能，同时采用压块固化技术以提高吸附剂的传热性能。实验结果表明，膨胀石墨的添加有效防止了吸附剂的结块和吸附性能的衰减，复合吸附剂吸附量高达0.47 kg NH₃•（kg salt）^-1;吸附剂与制冷剂之间的化学反应对反应器温度的变化有较大影响，蒸发温度不同导致吸附剂的吸附平台温度不同，且蒸发温度越低，吸附剂吸附合成反应速率越低;当蒸发温度从-35℃上升到0℃时，单位质量吸附剂制冷功率SCP（specific cooling power）从206 W•kg^-1增大到706 W•kg^-1。冷却水温度为25℃、蒸发温度为-30℃时，采用该固化复合吸附剂的吸附式低温冷冻系统SCP和COP分别高达350 W•kg^-1和0.34。