What can 2 girls do on a summer day when they are bored?
What you propose violates all 3 laws of thermodynamics, and is akin to building a perpetual motion machineThe heater works because the sun is a powerful radiator, and you can concentrate that energy to raise temperatureWithout a heat engine (referigerator), you can't move heat from cold ambient to hot ambient Nowyou could make a self-contained solar powered solid-state referigerator, using solar cells, and Peltier heat exchangers, but this is an active device - portable, but activeI've seen plans for these on the internetGoogle: Peltier solar powerThere's alot of hits and some DIY on page 1
