Solar energy conservation in greenhouse: Thermal analysis and experimental validation

The present study investigated six most commonly used shapes of greenhouses including: even span, uneven span, vinery, single span, arch and quonset type from energy consumption point of view under the climatic condition of Tabriz, Iran. The greenhouses were studied for both east west and north south orientation and the length width and height of them were kept same. The steady state analysis was used to calculate total additional energy (except solar radiation) required to maintain desirable temperature of plant. The effects of north brick wall on the energy consumption of greenhouses were studied and considered in model. Experimental validation of model was carried out in a single span, east-west orientated greenhouse for a typical day in winter. The results showed that the additional energy requirement to maintain the temperature desirable for the plants' growth was lowest in an east-west oriented single span greenhouse with north brick wall. It was concluded that north wall insulation can reduce heating demand of the greenhouse by as much as 31.7%. There was a fair agreement between experimental and theoretical results. The correlation coefficient and mean percentage error of developed model were calculated as 0.79 and -2.34%, respectively. (C) 2016 Elsevier Ltd. All rights reserved.