a . ! a) What is the minimum ambient outdoor temperature T.,min at which it is still possible to keep one liter of water boiling (T = 100 C) in a steel pot placed in the focal point of a parabolic solar cooker, on a sunny March day in Espoo, Finland? The diameter of the reflector disk is de 148 cm, and it focuses the light on the bottom of the pot which has the following dimensions: bottom diameter dp.b = 15.5 cm, top diameter dpt = 19.0 cm, height hp = 9.5 cm. Tips: Use the general heat balance of a solar collector, taking the concentration ratio into account, and considering the situation being similar to stagnation (no flow). Estimate the solar irradiance per disc aperture area that can be focused on the pot (sunny day in March in Helsinki). Estimate or look up a value for the heat loss factor UL of the steel pot (with a lid) and assume it constant. Estimate the solar reflectance of the reflector disc, and the solar absorptance of the pot