Effect of solar storage wall on the passive solar heating constructions

Three different greenhouse prototype designs: gable, flat and semi-circle roof shapes were investigated at the Faculty of Agriculture, Suez-Canal University, Egypt. Investigations were carried out to find out the effect of using the adobe (trombe) wall as solar heat storage used for greenhouse passives heating. The study was conducted under controllable weather conditions and outdoor under the prevailing weather conditions of the site of experiments. A range of cheap and readily available materials were said to form the adobe or adobe wall, i.e. clay (13.3%), clay painted with matt black paint (which has absorbability of 0.95%), sand (96.7% sandy attached by 2.5% gypsum, on the weight basis) and the sandy wall was painted black. These walls were compared with the controlled greenhouse without the wall. Investigations were carried out on greenhouse sandy soil (96.7%) with five different moisture contents of air dry, 25, 50, 75, and 100% from the field capacity. Greenhouse air temperature, soil-depth and solar wall temperatures gradient were investigated for the different walls of the different greenhouses deign under different investigation conditions. The study revealed that, the flat shape greenhouse surfaces gives higher air temperatures when the direction of the greenhouse was north–south, while the span surfaces shape for the east–west direction at the same investigation conditions.