Abstract
A CFD model was presented to simulate the distribution of air velocity and temperature in a greenhouse adopting the fan-pad cooling system in summer. The Boussinesq hypothesis was applied for the simulation of gravitation; the k-ε turbulent model and discrete ordinates model were selected to predict the distribution of air velocity and temperature inside greenhouse using the commercial software Fluent. The differences between simulated and measured air temperature varied from 0.9 to 4°C and the differences of air velocity were less than 0.15 m/s, which proved that the CFD method can estimate the distribution of air velocity and temperature in the greenhouse rationally and effectively. The validated CFD model was then used to evaluate the cooling effect and design the installment of fan and pad in terms of the crop size. The results implied that Case 3 and Case 5 should be chosen when the height of crop canopy varies from 2 m to 3 m. When it varies from 1 m to 2 m, all the cases can be effective except Case 1. When the canopy height is below 1 m, all the cases can be selected. This paper suggested that the CFD model can be used as an optimal tool for fan-pad evaporative cooling system in the greenhouse.
Highlights
Greenhouse is widely used to create a suitable environment for crop growth
This paper presented a computational fluid dynamics (CFD) model to analyze the air flow characters inside greenhouse using Fluent
The data obtained from the temperature sensors installed in the greenhouse was used to verify the CFD model
Summary
Greenhouse is widely used to create a suitable environment for crop growth. High temperature do harm to the crop, especially in summer. The experimental results showed that the deposition values on the crop were much lower than the values reached with spray guns [6]. Many researchers used mathematical model to evaluate the thermal performance of greenhouse cooling in greenhouse [8]. Mongkon et al evaluated geothermal cooling ability and studied corresponding parameters in Thailand by mathematical model [9]. Jain and Tiwari developed a mathematical model to study the thermal behavior after evaporative cooling (fan and pad type) in the greenhouse using MATLAB. To predict the temperature gradients along a greenhouse, Kittas et al proposed a climate model which incorporated the effect of ventilation rate, roof shading, and crop transpiration. The simulation indicated that high ventilation rates and shading contribute to reducing the temperature gradients [11].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
