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本文提出了一种新型的以冷制冷的氨水吸收式制冷系统。系统利用LNG气化释放的冷能作为冷源,通过少量的高品位冷能的利用来制取多量的低品位冷能,制冷循环采用氨水吸收式制冷系统。通过对系统的热力分析表明:当制冷温度(蒸发器蒸发温度)为0℃,蒸馏率为0.185,LNG冷能输入系统的温度为-60℃时,系统的性能系数为1.74。在此条件下对系统进行火用分析,发现吸收器的火用损失最大,其火用损系数约为24%,系统总的火用效率为41%。对系统进行特性规律分析,发现当蒸发器的蒸发温度不变时,发生器氨气蒸馏率的增加会使得发生器操作压力下降,LNG冷却温度下降,但同时系统的性能系数会增加。蒸馏温度越高,系统的性能越好,当制冷温度为10℃时,系统的性能系数可以达到1.8以上。
In this paper, a new type of ammonia refrigeration system with cooling and cooling is proposed. The system utilizes the cold energy released by the gasification of LNG as a cold source, generates a large amount of low-grade cold energy through the utilization of a small amount of high-grade cold energy, and adopts an ammonia absorption refrigeration system in the refrigeration cycle. The thermodynamic analysis of the system shows that the coefficient of performance of the system is 1.74 when the refrigeration temperature (evaporator evaporation temperature) is 0 ℃, the distillation rate is 0.185 and the temperature of LNG cold energy input system is -60 ℃. The exergy analysis of the system under this condition shows that the exergy loss of the absorber is the largest, the exergy loss coefficient is about 24% and the total exergy efficiency of the system is 41%. The characteristic analysis of the system shows that when the evaporation temperature of the evaporator is constant, the increase of the ammonia distillation rate of the generator will decrease the operating pressure of the generator and the cooling temperature of the LNG will decrease, but at the same time, the performance coefficient of the system will increase. The higher the distillation temperature, the better the system performance. When the refrigeration temperature is 10 ℃, the coefficient of performance of the system can reach above 1.8.