Transient modelling of multi-pass solar thermal collector with sensible energy storing matrix

Transient modelling of multi-pass solar hot air dryer as a physical system is presented in this present work. SIMSCAPE/SIMULINK tool was utilized for the theoretical study of hot air passing through transparent flat plates and anodized aluminium as solar thermal collector. Pebble bed made of granite was obtained locally to sever as the sensible heat reservoir. The thermal energy balance was resolved using lumped component technique. The parameters, variables and operating conditions of materials that constitute the thermal system forms the modelling input with available weather data collected in the Solar Research Site, Universiti Teknologi PETRONAS (4.385693° N and 100.979203° E). The model revealed improved on the multi-pass system performance efficiency by 12.4% and 10.1% when compared to the reported single pass and double pass solar air heaters. Closed loop control mechanism was imposed to achieve a steady heat flow 471.2 Js^-1 to the drying compartment. A temperature gradient of 31.21 K was predicted which is suitable for the drying operation of many agricultural products. The theoretical result was in agreement with output obtained from the humidity controlled drying test system in the Solar Energy Laboratory, Universiti Kebangsaan Malaysia. However, there was need to improve the boundary condition accuracy and flexibility to accept various materials for system boundary.