TR-04.pdf

Lid gaps are the major cause of heat loss and variability in the HotPot solar cooker, according to research by Paul Arveson, Director of Research at Solar Household Energy. The HotPot has a black enameled steel pot surrounded by a glass liner and a glass lid, with a polished anodized aluminum reflector. Experiments conducted over three years showed significant variations in heating performance, despite consistent solar irradiance and low wind speed. The research found that ensuring the lid was placed on the pot at exactly the same angular position improved repeatability, and sealing the lid with tape also improved repeatability, but complete sealing is not feasible due to pressure buildup and safety concerns. Visualization of vapor flow through lid gaps using dry ice and water simulated the effect of boiling water escaping from the pot lid gaps.