Effects of Shading and Roof Sprinkling in Venlo-Type Greenhouse in Summer

The effects of shading and roof sprinkling based on natural ventilation were experimentally studied in a Venlo type multi span greenhouse. Air temperature, humidity and solar radiation inside the greenhouse were measured to compare the cooling effect of shading and roof sprinkling. Under the experimental condition, the mean indoor air temperature was 2.1℃ lower than that outdoor, the largest air temperature difference was 4.4℃ . The results showed that the measures of shading and roof sprinkling based on the natural ventilation could effectively cool down the greenhouse in summer. Shading, roof sprinkling and roof opening played different roles in the greenhouse. Different from other evaporative cooling system, the roof sprinkling system did not increase the air humidity inside the greenhouse. The distributions of air temperature and humidity inside the greenhouse were uniform under the experimental conditions. The methods could effectively reduce the air temperature and energy consumption in greenhouses.