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. ...
In regions with Mediterranean climates, high indoor temperatures, particularly during the summer months due to high solar radiation, limit plant growth in greenhouses. Due to the inadequacy of natural ventilation and shading practices commonly used to reduce indoor temperatures during these months, evaporative systems have become widely used in recent years. However, in regions where water is scarce, the high water volumes required for evaporative cooling are an issue that greenhouse operators should not overlook. The aim of this study was to determine the cooling effect, relative humidity effect, cooling efficiency, and water consumption of fan and pad cooling systems under Mediterranean climate conditions. For this purpose, measurements were taken in a Gothic-roofed greenhouse between June and September, when temperatures are high. The pad area used in the greenhouse was 7.5 m2, the water flow rate was 10 L per minute per meter of pad, and the air change rate was 0.066 m3m-2s-1. The average cooling effect, relative humidity effect, cooling efficiency, and water consumption in June were determined as 7.9 °C, 19.4%, 60.7%, and 9.82 L·m-2, respectively. In July, these figures were 5.6°C, 21.9%, 52.1%, and 9.73 L·m-2, respectively; in August, 5.4°C, 14.5%, 50.9%, and 10.2 L·m-2; and in ...
