Experimental comparison of heat storage pots containing powdered iron filings and erythritol using parabolic dish solar cookers

Abstract

Solar cookers cannot be used without heat storage during cloudy periods or at night. Heat storage can be used for cooking during cloudy periods and at night. Two storage cooking pots are thus experimentally evaluated to compare their heat storage performances. A latent heat storage material (erythritol) is compared with a sensible heat storage material (powdered iron filings) during solar cooking periods using parabolic dish solar cookers and during storage cooking periods using wonderbag insulating solar cookers. The powdered iron filings storage pot shows a faster temperature rise during the no-load test, attaining a maximum pot temperature above 200 oC compared to 190 oC for the erythritol due to the higher thermal conductivity of iron filings. However, the storage temperature for erythritol at the end of the no-load lest is around 180 oC compared to 140 oC for iron filings. For the storage cooking period, the erythritol storage pot can boil water. In contrast, the iron filings storage pot shows ineffective heat transfer, achieving a maximum temperature of only about 70 oC. For the simultaneous heating and storage test, the iron filings pot shows higher temperatures during the solar cooking period and much lower temperatures during the storage cooking period than the erythritol pot.