本文采用巨正则蒙特卡洛(grand canonical Monte Carlo,GCMC)方法,基于UFF(universal force field)和TraPPE(transferable potentials for phase equilibria)力场,对ZIF-8(Zn)吸附NH_(3)进行了分子模拟研究,并结合分子模拟结果和吸附式...本文采用巨正则蒙特卡洛(grand canonical Monte Carlo,GCMC)方法,基于UFF(universal force field)和TraPPE(transferable potentials for phase equilibria)力场,对ZIF-8(Zn)吸附NH_(3)进行了分子模拟研究,并结合分子模拟结果和吸附式制冷热力学循环模型,研究了ZIF-8(Zn)/NH_(3)工质对的吸附性能和制冷性能。研究表明:在等温条件下,ZIF-8(Zn)对NH_(3)的吸附量随压力的增大而提高,298 K和398 K下饱和吸附量分别达到0.305 g/g和0.231 g/g;同一温度下的总吸附热也随压力的增大而上升,这主要归因于NH_(3)分子间相互作用产生吸附热的增加,而ZIF-8(Zn)与NH_(3)相互作用的吸附热维持在较稳定的状态;NH_(3)在ZIF-8(Zn)中的吸附密度分布结果表明NH_(3)在金属位点处被大量吸附,难以通过ZIF-8(Zn)部分孔径较小的孔道,成功通过孔道的NH_(3)在ZIF-8(Zn)的SOD笼内部聚集;该吸附式制冷工质对制冷性能稳定,对温度有较好的适应性。制冷温度为283 K(通风工况)的制冷系数为0.43,制冷温度为243 K(冷冻工况)的制冷系数仍能达到0.38。展开更多
A closed-cycle solar-powered adsorption cooling system is designed.The system is mainly composed of the evacuated tubular solar collectors with an area of 150 m^2,two adsorption chillers with a rated cooling capacity ...A closed-cycle solar-powered adsorption cooling system is designed.The system is mainly composed of the evacuated tubular solar collectors with an area of 150 m^2,two adsorption chillers with a rated cooling capacity of 15 kW,a cooling tower,fan coils and circulating pumps.The experiments were carried out to study the operating characteristics and the performance of the system.It is found that the operation of the system presents wave characteristics because of low water capacity.The water temperatures of the inlet and the outlet of the solar collector array cyclically swing since the water entering the solar collector array comes directly from the adsorption chillers.Besides,the inlet water temperature of the adsorption chillers varies distinctly.However,the cooling effect of the system is satisfactory.Compared with an open-cycle system,the closed-cycle system has the advantage of a high electric COP（coefficient of performance）because of the reduced use of circulating pumps.展开更多
Thermochemical sorption refrigeration powered by low-grade thermal energy is one of the energy-saving and environment friendly green refrigeration technologies. The operation principle of sorption refrigeration system...Thermochemical sorption refrigeration powered by low-grade thermal energy is one of the energy-saving and environment friendly green refrigeration technologies. The operation principle of sorption refrigeration system is based on the thermal effects of reversible physicochemical reaction processes between sorbents and refrigerants. This paper presents the developing study on the different thermochemical sorption refrigeration cycles, and some representative high-efficient thermochemical sorption refrigeration cycles were evaluated and analyzed based on the conventional single-effect sorption cycle. These advanced sorption refrigeration cycles mainly include the heat and mass recovery sorption cycle, double-effect sorption cycle, multi-effect sorption cycle, combined double-way sorption cycle, and double-effect and double-way sorption cycle with internal heat recovery. Moreover, the developing tendency of the thermochemical sorption refrigeration is also predicted in this paper.展开更多
基金The National Natural Science Foundation of China(No.50876064)the Ph.D.Programs Foundation of Ministry of Education ofChina(No.200802481115)
文摘A closed-cycle solar-powered adsorption cooling system is designed.The system is mainly composed of the evacuated tubular solar collectors with an area of 150 m^2,two adsorption chillers with a rated cooling capacity of 15 kW,a cooling tower,fan coils and circulating pumps.The experiments were carried out to study the operating characteristics and the performance of the system.It is found that the operation of the system presents wave characteristics because of low water capacity.The water temperatures of the inlet and the outlet of the solar collector array cyclically swing since the water entering the solar collector array comes directly from the adsorption chillers.Besides,the inlet water temperature of the adsorption chillers varies distinctly.However,the cooling effect of the system is satisfactory.Compared with an open-cycle system,the closed-cycle system has the advantage of a high electric COP（coefficient of performance）because of the reduced use of circulating pumps.
基金Supported by the Key Project of the Natural Science Foundation of China (Grant No. 50736004)
文摘Thermochemical sorption refrigeration powered by low-grade thermal energy is one of the energy-saving and environment friendly green refrigeration technologies. The operation principle of sorption refrigeration system is based on the thermal effects of reversible physicochemical reaction processes between sorbents and refrigerants. This paper presents the developing study on the different thermochemical sorption refrigeration cycles, and some representative high-efficient thermochemical sorption refrigeration cycles were evaluated and analyzed based on the conventional single-effect sorption cycle. These advanced sorption refrigeration cycles mainly include the heat and mass recovery sorption cycle, double-effect sorption cycle, multi-effect sorption cycle, combined double-way sorption cycle, and double-effect and double-way sorption cycle with internal heat recovery. Moreover, the developing tendency of the thermochemical sorption refrigeration is also predicted in this paper.
