scholarly journals Analysis and Optimization of the Fan-Pad Evaporative Cooling System for Greenhouse Based on CFD

2014 ◽  
Vol 6 ◽  
pp. 712740 ◽  
Author(s):  
Jiaoliao Chen ◽  
Yanwen Cai ◽  
Fang Xu ◽  
Haigen Hu ◽  
Qinglin Ai
Keyword(s):  
Cooling System ◽  
Evaporative Cooling ◽  
Discrete Ordinates ◽  
Turbulent Model ◽  
Cfd Model ◽  
Air Velocity ◽  
Boussinesq Hypothesis ◽  
Evaporative Cooling System ◽  
Cfd Method ◽  
Discrete Ordinates Model

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.

scholarly journals The effect of air velocity on the performance of the direct evaporative cooling system

2022 ◽  
Vol 1217 (1) ◽  
pp. 012016
Author(s):  
Z Hassan ◽  
M S Misaran ◽  
N J Siambun ◽  
M Adzrie
Keyword(s):  
Cooling System ◽  
Evaporative Cooling ◽  
Cooling Capacity ◽  
Airflow Rate ◽  
Cooling Efficiency ◽  
Air Velocity ◽  
Input And Output ◽  
Direct Evaporative Cooling ◽  
Evaporative Cooling System ◽  
Air Speed

Abstract This experimental study aimed to determine the effect of airflow velocity on the performance of a direct evaporative cooling system. Rectangular-shaped honeycomb cooling pads with a length of 34 cm, a width of 25 cm, and a thickness of 3.5 cm are used as cooling media. The main parameters of the study are low air velocity (2.3 ms−1), medium (3.2 ms−1), and high velocity (3.7 ms−1). The data collected include dry bulb temperature, wet bulb temperature, output air temperature, input and output air velocity, input and output humidity, and solar radiation. These data are used to determine saturation efficiency, cooling capacity, temperature decreases, and feasibility index. The experimental results are presented in the form of tables and graphs and analysed based on existing theories. The results showed that the evaporative cooling system could produce output temperatures up to 27.5°C with input 31.4°C at low airspeed, 27.97°C with input 31.47oC at medium speed, and 27.7°C with input 31.30°C at high air speed. It was concluded that a low airflow rate would add to the cooling efficiency, and the higher the airflow rate, the lower the cooling efficiency. The results showed that evaporative cooling is achievable with a feasibility index of 19.89 ≤ F*≤ 20.67. The results also affirmed that cooling capability is higher where the feasibility indexes are comparatively low.

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