Summary:

Greenhouses are agricultural buildings where production takes place throughout the year. In greenhouse cultivation, the objective is to ensure economically highest yield by means of adjusting the greenhouse indoor climatic conditions. During summer, cooling is needed in order to prevent overheating in greenhouse. The cooling in greenhouses is carried out via fan pad cooling systems. Hereby study aims at determining the effects of highest and lowest local humidity on indoor temperature changes, through detection of the influence of outdoor relative humidity on the system efficiency and cooling rates. The research is realised in the 24 m long, 10 m wide glasshouse in the city of Isparta. It is found out that temperature reduction values in greenhouse are highly influenced by the local highest and lowest relative humidity. According to the outcomes of the study, in a day when the outdoor relative humidity is low, temperature level rises around 6-7oC compared to a day with higher humidity; therefore, the outdoor relative humidity comes up as a significant parameter for improving system efficiency. It is concluded that the most suitable hours for starting the system is 9.00-10.00 a.m., when the temperature begins to increase, for a more cooling efficiency.