Experimental Study On The Heat Transfer Performance For A Novel Solar Air Collector Based On The Solar Energy-phase Change Thermal Energy Storage "TRI-layer" Structure Wall

There are extensive solar energy resources and the amount of solar radiation peryear has over than6GJ㎡almost4/5area in north farming area in China, and theannual sunshine hours more than2200h, it is significance for in-season production offruits and vegetables. Solar greenhouse is a protected-horticulture building for cropgrown in winter, the theory is using greenhouse effect to improve the indoor thermalenvironment, and it has been widely used in northern China. The north wall of solargreenhouse is the most important structure to ensure the solar radiation shined ingreenhouse could be effective used and the function of north wall has united theendothermic, heat storage and thermal insulation as one, so it is an extremelyimportant role in control of greenhouse thermal environment. But in the traditionalway, the solar energy use patterns in solar greenhouse are mostly by the passivemethod, due to the limitation of thermal conductivity on the walls, the temperaturechanges range has only250~400mm along the depth of walls which affect by solarradiation, lead to the heat storage capacity of north walls was not been fully utilized,and the greenhouse indoor thermal environment is difficult to ensure the requiredcondition for crops growth in the winter and the phenomenon of low temperature buthigh humidity has emerged.Based on previous research, our group proposed the construction method of solarair collector-PCM walls integrated system, against the structural characteristics ofsolar greenhouse, we have developed a novel of multiple surfaces trough solar aircollector dedicated in solar greenhouse. This article focuses around the followingquestions:1. Describes the structural characteristics of the multiple surfaces trough solar aircollector and the its heat collection theory;2. Built a collector thermal performance experimental system in BJUT, andinvestigated the effect of collector outlet air temperature, heat collection andcollection efficiency on the factors of air velocity, inlet air temperature, collectorinsulation performance and solar radiation, et al; and a real greenhouse combinedsolar air collector-PCM walls built in Jinzhong City, Shanxi Province, to investigatethe effect of collector thermal performance on the length of collector and the systemperformance.3. Based on the experiment result and the collection thermal theory, the collectorthermal analysis calculation model has been found and verified by the experiment,and this model is used to predict the running effect of the collector in winter;...