蓄热式换热器周期性换热过程的性能分析

Performance analysis of periodic heat transfer process of energy-storage heat exchangers

针对暖通空调涉及的周期性换热过程(如相变地板、夜间通风、地埋管换热等)进行分析。周期性换热过程可视为等效冷源与等效热源之间非同时的换热过程,地板、土壤等中间媒介起蓄能和间接换热的作用。提出了整个换热过程的热阻分析方法,认为换热量由取热阶段流体与中间媒介表面换热过程、放热阶段流体与中间媒介表面换热过程及中间媒介自身导热过程三方面的热阻决定。计算得到地板白天蓄热夜间放热过程、夜间通风蓄冷过程、地埋管以年为周期的换热过程中,三部分热阻所占比例,分析了蓄热性能的制约因素,为蓄热式换热系统的设计与优化提供参考。

Analyses the periodic heat transfer processes in HVAC system,including those in the floor with phase change materials,night ventilation,buried pipe heat exchanger.The periodic heat transfer process can be regarded as non-simultaneous heat transfer process between equivalent cold source and heat source,and the media such as floor and soil play the role of heat storage and indirect heat transfer.Proposes analysis method of the heat resistance for the whole heat transfer process,and considers that the amount of heat exchange is determined by the heat resistance of three parts,i.e.,the heat absorption process from hot fluid to media surface,the heat release process from media surface to cold fluid,and heat conduction process within the media.Gives the proportions of the three part resistances in these processes including the daytime-heat-absorption and the nighttime-heat-release of floor,the ventilation cool storage in the nighttime,and yearly heat transfer of the buried pipe,and analyses the factors restricting thermal storage performance,which is helpful for the design and optimization of the energy-storage heat exchange system.