Trombe Wall Heat Transfer Process And Optimization Design Research

Trombe wall is a major application collection hot components in passive solarhouses, whose thermal performance has important influence on the heating effect forpassive solar houses. Because of the temperature outside parameters and the sunradiation parameters in cyclical change, so the heat transfer process of Trombe wall is acyclical unsteady process, the research for Trombe wall’s thermal properties must be intransient conditions. This paper use the theoretical analysis and the field test and thenumerical simulation of the three methods to study.Established Trombe wall heat transfer process mathematical model, give thecomputation method of the instantaneous incident solar radiation to wall surface,andthe mathematical description of outdoor cyclical temperature wave; Established Trombewall and room palisade structure heat balance equations, and the control equations ofthe air interlayer’s flow and heat transfer process are given, and give the calculationmethod of the quantity of heat conduction and heat convection heating. Through theequations of the simultaneous, obtained the main influencing factors for Trombe wallthermal properties.The the field test research object is a solar pilot project in Qinghai provinceGangcha county, using the field test method to study the heat conduction and heatconvection rule of the Trombe wall, and the indoor temperature change rule. The resultsshow that: the Trombe wall of "240mm brick wall+50mm benzene board+corrugated iron" structure have very high heating efficiency, which can reach34.5%.Obtained the best opening and closing management scheme for the air vents, which isopening the vents after sunrise2hours and closed the vents before sunset1hour. By using numerical calculation method to study the influence the major factors ofTrombe wall’s thermal properties. Analysis the air interlayer thickness, vents area, thecenter distance between the up vent and the down vent, wall thickness, and wallmaterials influencing factors for the Trombe wall thermal performance, and make use ofthe field test data to verify the numerical calculation method. The results show that thebest value range air interlayer thickness for50mm to100mm; Vents area of therecommended value for wall body area of1%to2%. Increase the center distance of heup vent and the down vent to significantly improve air flow rate of the air interlayer, soas to increase heat convection amount;120mm thin wall thermal efficiency to be higherthan240mm and370mm thick wall, but at night it will happen serious hot flow backphenomenon,240mm brick wall is not far from370mm brick wall in thermalefficiency, in cold region, consider using370mm brick wall, other areas use240mmbrick wall; Use materials of low volume heat capacity and small coefficient of thermalconductivity not only can improve the thermal insulation property of the wall at night,but also can improve Trombe wall’s thermal efficiency.The results of this paper can provide the reference for the thermal design of themain components of Trombe wall.