Determination of adjustment tracking time in two types of solar cookers by ray-tracing method

Abstract

In this work, the effect of time adjustment on solar cookers tracking systems was studied. The concentrated spot at the focal point of the parabolic reflector and the illuminated absorber surface of the box cooker are simulated by the software TracePro. For that purpose, the two cookers are supposed in a fixed position (without manual or automatic tracking) during all period of simulation. Using light tracing simulation, the losses of the box solar cooker (BSC) surface absorber and the parabolic solar cooker (PSC) focal point are calculated and visualized. It is found that the losses from the absorber surface of the BSC ranged from 3.3 to 229.4 W, whereas it was varied between 23.4 and 51.2 W from the focal point of the PSC for the same time interval (from 12:00 to 12:30 solar time). The simulated results have shown that the concentrated radiation on the receivers can be improved by adjusting solar cookers at the adequate moment. The time adjustment for PSC must be smaller than that of the BSC, in raison of higher losses in the receiver of PSC. The parabolic solar cooker must be adjusted every 8 minutes; however a time adjustment of 20 minutes is required for the box solar cooker. In respect to the optimum adjustment time, the box and parabolic solar cookers will have a higher concentration with considerably reduced losses.