Simulation of thermal performance of solar greenhouse in north-west of Iran: An experimental validation

Application of solar energy in greenhouse heating during the cold months could be of great importance. In this study, six shapes of greenhouses including: uneven span, even span, single span, vinery, quonset and arch type were compared from solar radiation availability point of view. A dynamic model was developed to predict all the internal greenhouse temperatures including inside air, soil surface and north wall temperatures for the selected greenhouse. In this model the radiation component of the heat transfer was used along with the other heat transfer modes. Experimental validation to obtain required parameters was conducted in single span greenhouse (in east-west orientation). The results showed that, as compared to other shapes, the single span shape greenhouse oriented in east-west orientation received about 8% more solar radiation during all the months in a year. It was also determined that using brick wall at north side of the greenhouse can reduce radiation energy loss in this type of greenhouse. The average value of the cover transmittance was estimated to be 0.76 during the period of the experiment. A good agreement was obtained comparing measured and predicted values.