Performance Evaluation of Solar Radiation for Food and Agriculture Dryer

¹ Expert Center of Innovative Health Food (innoFood), Research and Development Group for Bio-Industries, Thailand Institute of Scientific and Technological Research (TISTR), Pathumtani, Thailand
² Expert Center of innovative Agriculture (innoAg), Research and Development Group for Bio-Industries, Thailand Institute of Scientific and Technological Research (TISTR), Pathumtani, Thailand

^* Corresponding author: sriwichai@tisir.or.th

Abstract

This paper is attempt to utilize the solar radiation in a solar dryer for saving the day-light, energy, and environment. Solar dryer was designed based on thermal analysis heat transfer equations, then it was constructed and tested in Thailand (on a latitude 14^°N. and longitude of 100^°E). The main three stages were carried out in order to test solar dryer performance. Initially, solar energy consumption data was recorded from 8:00 a.m. to 5:00 p.m., then thermal analysis without load condition was conducted and and tested with fresh fruit sample. In the final stage, the data was compared with an electrical oven. Recording results for the system showed that the solar energy consumption was 313 W/m² 493 W/m² (horizontal irradiance), ambient temperature was at 29.5 ^°C 40.3 ^°C, and relative humidity was at 36.2% 52.2%, respectively. The calculated thermal energy of solar dryer was approximately 41 m³/h with the rate to remove moisture content out of the system at 0.21 kg/h in average. The average temperature inside the dryer is 47.4 ^°C. According to the Psychrometric chart, the constant volume is approximately 0.92 m³/kg. Experimental drying test with fresh fruit in the solar dryer showed that a moisture content of fresh fruit was recorded to be at 81.2% and reduced to 8.4%. Comparatively, under the similar temperature condition, drying with electrical oven is faster for dehumidifying than solar dryer about 21%. However, solar dryer is considered to be more environmentally-friendly than electrical oven. It is also found that the result showed no more differences in dehumidity when testing with the other agricultural samples at the similar drying rate. The results also revealed CO₂ mitigation through a solar dryer system was 2.6 kg/day, energy-saving was 5.63 kWh/day. Therefore, solar dryer system is demonstrated to be an alternative saving sustainable method for all.