Development of a Solar Paddy Dryer by Fluidization Technique Using Heat from a Solar Pond
Abstract
In this research a new approach for employing heat from solar pond as the main source of energy for paddy drying was introduced. The drying test rig was designed, fabricated and evaluated. The rig consists of paddy dryer and solar pond. The area of solar pond was 50 m2 and a depth of 2.5 m was built at Khon Kaen in North-Eastern Thailand. Air mass flow rate was measured by an orifice plate, the temperatures were monitored by K type thermocouples, the solar insolation was recorded by a pyranometer. One of the objectives in this research was to evaluate the effect of mass flow rate and interval time of paddy discharging on the rate of paddy drying by the dryer and was conducted at temperatures of 40, 50, and 60 degrees Celsius at the flow rates of hot water of 0.56, 0.75, and 1.67 liters per minute respectively. The wind speed to be applied was 5 m/s. Heat in the experiment was obtained from the solar pond. The experiment was conducted at the flow rates of water of 2, 2.5, and 3 liters per minute respectively and was continuously run for 24 hours. In addition, the experiment took 3 days for each of the flow rates and data were recorded every 1 minute. The results showed that the flow rate of 2.5 liters per minute could take heat into application better than the flow rates of 2 and 3 liters per minute. At such the flow rate, moisture dropped from 23.4% to 15% for the first time of drying and for the second and third times, the moistures dropped to 13% and 11% respectively. Reduction in moisture content of the paddy met the criteria set which was 1% to 5% per round of drying.