Mathematical Modeling of a Greenhouse Performance with Evaporative Cooling System

Sahar Gaafar Ahmed; Mohamed Ayoub Ismail; Abdelmoneim Elamin Mohamed; Adam Bush Adam

Volume : VIII, Issue : VII, July - 2019

Mathematical Modeling of a Greenhouse Performance with Evaporative Cooling System

Sahar Gaafar Ahmed, Mohamed Ayoub Ismail, Abdelmoneim Elamin Mohamed, Adam Bush Adam

Abstract :

The study was conducted at the Demonstration Farm of the Faculty of Agriculture, University of Khartoum, Shambat (32⁰ 51 ̀ E, 15⁰ 65 ̀ N and 380 m above mean sea level) under greenhouse conditions for two conductive seasons (2009 and 2010). The objective of this study was to develop a one-dimensional conduction and convection heat transfer model to simulate the thermal behavior in a greenhouse equipped with evaporative cooling system and comp� the predicted results with measured data. The model was written in Visual Basic V. 6.0 Programming Language. A greenhouse of Quonset type with dimensions 20× 9×3m was used for carrying out the experimental work. The model predicted the temperatures inside the greenhouse using input data of outside air temperature (�C), mass flow rate of air the greenhouse from fan (kg/sec), latent heat of vaporization for both outside and inside the greenhouse, absolute humidity of the outside air and inside at the fan, overall heat conductance (U), the area of greenhouse m2 through which heat was transferred. 100 % Evaporative cooling efficiency was recorded in September during 2009, compared to 58% in June during 2010. Statistical analysis were carried out to check the accuracy of the developed heat transfer model. The results showed that there was a close agreement between measured and predicted values during the first season while there was slightly difference in the second season. The developed heat transfer model predicted the temperature within the bounds of the experimental error (close to zero). The time taken by the computer programme to predict greenhouse temperature was 2.5 second/simulation day. It is concluded that, statistical tools for checking the accuracy of the developed mathematical models should be followed and adopted.