Objective of the present study was to carry out detail experimentation and then analyze solar cabinet dryer. The loading capacity of the dryer was about 2kg of fresh product per batch. The dryer is of both natural and force mode type based solar cabinet dryer. The experiments were carried on both natural and force mode by using chili as the raw product. Various readings related to temperature and humidity at the desired points were measured with the help of thermocouples and hygrometer respectively, also air flow rate and solar intensity were measured with the help of anemometer and pyrometer. These experiments were carried in ITER, SOA UNIV Bhubaneswar (India), in this various parameters related to solar dryer was not only calculated but also natural and force mode was compared in terms of drying rate. The data are presented in terms of tables and graphs. It was found that the drying of chili in natural mode would take around 50-56 hrs and drying in force mode will take about 10-21 hrs depending on whether we are using heater as an external source of heat or not. It will take around 105 hrs in open drying of chili. The chili was reduced from the initial moisture content of 86.5(wb) to 7.3(wb).[23-24]Further, the dryer was modified by implanting evacuated tube above the black plate collector incorporating with PCM( Paraffin Wax) as the heat storage medium behind the black plate. This in turn has increased the performance of the dryer. After that, an oil was filled in the annular space between the copper and the glass tube by mixing it with carbon graduals. The mixture was a semi solid type of slug which acts as a conducting medium between glass and copper tube. The performance of the dryer was seen to be increased surprisingly. Design and various parameters have been discussed here for clear in-depth of the topic. [25] |
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Keywords: Solar Drier, Solar Collector, Pyrometer, Anemometer, Thermocouples and Hygrometer