Drying performance and thermal transient study with solar radiation supplemented by forced-ventilation

A solar attire or cloth dryer has been designed, constructed and experimentally tested. The result shows that solar dryer supplemented with forced-ventilation has higher drying rate of 0.43 kg h−1 and shorter completion drying time of 3 hours compared to solar dryer with natural ventilation which has a drying rate of 0.25 kg h−1 and drying time of more than 4 hours for a typical day. Consistent with the experiments, the preliminary computational results based on the Navier–Stokes thermal transient simulation technique able to demonstrate the temperature rise prevailing in the solar cum forced-ventilation system associated with the internal heat flux due to solar radiation and moisture removal. Good agreement is found between the numerical simulation and the corresponding experimental measurements. Parametric study by simulation was conducted subsequently to investigate the feasibility of employing higher capacity fans, i.e. higher forced-ventilation rates, on energy stored if the current system operated under same ambient weather conditions. Initial comparison studies based from both experiment works (natural ventilation vs. forced-ventilation) and simulation (temperature rise vs. forced-ventilation rates) have shown that the application of higher ventilation rates would possibly further improve the dryer's performance and cause an increase of local heat flux and temperature rise, especially in the early stage of drying.