A Comparison of Temperature for Parabola and Sinusoidal Greenhouse Solar Dryer by CFD

Abstract

This paper presents comparison for the thermal efficiency between a parabola greenhouse solar dryer and sinusoidal greenhouse solar dryer by computational fluid dynamics (CFD). The concept of design is to find ways to increase the solar area of the greenhouse solar drying. The greenhouse solar dryers used in the analysis are 2 types: 1) parabola greenhouse dryer has a one side solar roof structure for received solar energy area of 95.47 m2 and 2) new design greenhouse is a sinusoidal greenhouse dryer has a two-sided solar roof structure for received solar energy area of 96.63 m2, which increases the solar receiving area of 1.22%. The both volume of greenhouse dryers was about 94 m3 (a parabola greenhouse dryer is a standard plant greenhouse dryer from department of alternative energy department and efficiency, Ministry of Energy, Thailand. The size: 8.2 of length and 6.0 of wide). The greenhouse dryer were received an average heat flux from the solar of 1,000 W/m2 at 11.00am. - 02.00pm. in Udon Thani province, Thailand (in the absence of cloud cover) and the outside temperature is 28 °C. This experiment is an analysis of the effects of 6 hours of solar radiation at the same time for both greenhouse dryers to compare the temperatures using the computational fluid dynamic (CFD) program. The raw materials are drying at higher temperatures can be faster drying rate that resulting to drying time period is lower. From the results of the simulation, it was found that the average drying temperature of 6 hours for the sinusoidal and the parabola greenhouse is 322.26K (49.11°C) and 321.20K (48.05°C), respectively. The time of drying value of the sinusoidal greenhouse solar dryer is 3.40 hours at an average temperature value of 322.26K (49.11°C) and the parabola greenhouse solar dryer is 4.70 hours at an average temperature value of and 321.20K (48.05°C). In conclusion, a sinusoidal greenhouse has higher average drying temperatures with compared to a parabola greenhouse for the same drying time period. The sinusoidal greenhouse drying period takes less than the parabola greenhouse and higher drying efficiency.