Dry Chamber Temperature Lab Report

A force convection solar dryer constructed using local material (figure 1) and evaluated for the drying of local yam variety Dioscorea Rodundata cultivar ‘Dente’. The dryer was positioned facing south with an angle inclination of 18o.

Temperature profiles of the collector and within the drying chamber indicating ambient temperature, inlet and outlet temperature of the collector, drying chamber temperature and relative humidity of ambient and within the drying chamber have been plotted (Figure 4and5) to depict the thermal performance of the dryer.

4.1.1 Preliminary test

A no load test was conducted to test some parameters of primary interest such as the temperature of various parts of the collector and drying chamber and relative humidity of the

Aissa et al. (2012) reported that temperature of the drying air inside the dryer chamber is critical factor that affects the drying process. The difference between the mean collector inlet temperature (Tout) and the temperature inside the drying chamber (Tdc) for loading capacities of 2.4kg, 7.2kg and 11.8 kg was 16oC, 16oC and 14oC.

The moisture content variations with drying time are shown in Figure 5(a) (A-C). It shows a steady decline of moisture with time as expected. From the drying curve, it is obvious that the temperature rise inside the chamber was enough to remove moisture from the products. Dry air passing through the lower trays (tray 3 for 2.4kg and tray 6 for 7.2kg and 11.8kg) had higher temperatures and low relative humidity levels than the air leaving the upper trays (tray 1) which had less temperature and high relative humidity levels this resulted in samples on the lower trays drying faster than same on upper trays. This is in agreement with observations made by Khan et al.