A solar collector was also placed inside the NWIGHD. It is shown in Fig. 1(a). The objective of the designing the solar collector was to store the solar heat energy during the sunshine hours and further that stored heat energy was supplied to heat the inlet air. Now this heated inlet air can be utilised to remove moisture from the crop. Two black PVC sheet with dimension of 1.45 m × 0.950 m was used to fabricate the solar collector. The upper layer consist 10 × 7.0 equidistant circular holes of 70 mm diameter, which is made for better heat transfer from collector to inlet air. The distance between upper and lower layer is 80 mm and structure of the collector is made up of box type iron strip. The tray is made of stainless steel wire meshed with the dimension of 1.4 × 0.9 m2 and placed on runner at 0.25 m height so as to ensure a reasonable level of air circulation under and around the drying material. Fig. 1(a) shows the north wall insulated greenhouse dryer without solar collector and Fig. 1(b) shows the north wall insulated greenhouse dryer without collector.