| The flat-plate solar air collector has been widely used because of its simple structure, andeasily combining with architecture. There is a common problem of flat-plate solar aircollector that the efficient is low. In this paper, the efficiency of the flat-plate solar aircollector and energy density are further improved by humiding the air.Firstly, introduces the solar energy resources and development of and solar air collectorat home and abroad and set up wet air computational equation of the thermal physicalparameters with variable of the air temperature and moisture. Based on introducting theprinciple of evaporative cooling, using the forward difference method to calculate the processfor heat and mass transfer between air and water in spray chamber. On the basis of theoreticalanalysis on the thermal efficiency of flat plate solar air collector, put forward the given flatsolar air collector model thermal efficiency calculation method.The regular pattern that several factors influence to the thermal efficiency of the collectoris studied by using FORTRAN programming under the dry air or relative humidity of50﹪humid air conditions. Several factors include: solar radiation intensity, air channel height,inlet air flow rate, inlet air temperature and environmental temperature and so on on. Comparetwo kinds of results and include: The efficiency of flat-plate solar air collector under therelative humidity of50﹪of wet air is higher3.77﹪to7.59﹪than that of the dry air, and thethermal efficiency law effected by the various factors on the dry and wet air collector issame.In other words, the thermal efficiency law affected by the various factors of flat-platesolar air collector has nothing to do with the working medium.Based on theoretical calculation of flat-plate solar air collector thermal efficiency andspray chamber, this paper futher puts forward models of humidification flat-plate solar aircollector group by using solar collector to heat air and spraying chamber to isenthalpiccooling humidification air,then presents a method for calculating the thermal efficiency of themodel. The thermal efficiency of humidification flat-plate solar air collector under thecondition that the spraying chamber outlet air relative humidity is50﹪and80﹪is calculatedby using FORTRAN programming.The results dedicades: as the number of sets ofhumidification flat-plate solar air collector increases, outlet temperature of the spray chamberin each unit, moisture content at the exit, the top loss coefficient and the enthalpyincreased,while the useful energy gain and efficiency of heat collector declined; For themoisture content at the exit efficiency, enthalpy and useful energy gain of each unit,the Spraychamber outlet relative humidity of80%is higher than50%. On the other hand, the outlettemperature of spray chamber and the top loss coefficient have contrary result. When the number of sets of wet air collector plate increasing is more than10groups, the rate of changetate is reduced of outlet air temperature, the top loss coefficient and collector efficiency, whilethe moisture conten of outlet air, the enthalpy of moist air and the benefiting of total usefulenergy are growthing with a linear.The humidification flat-plate solar air collector group has high outlet air temperature,high air moisture content, high energy density and so on, which is widely used to the solarenergy heat pump, super hydrophobic surface evaporator and water desalination processing,etc in order to effectively reduce air flow and evaporation and heat transfering area required. |
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