Could we make a practical solar fridge?

Thread starter anorlunda
Start date Sep 9, 2022
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fridge Practical Solar

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The discussion revolves around the feasibility of creating a solar-powered refrigerator suitable for off-grid living. The proposed design involves a chest freezer divided into two compartments, utilizing a variable speed BLDC compressor powered directly by solar panels, eliminating the need for inverters or MPPT controllers. The concept includes using frozen water as thermal storage to maintain cold temperatures for food storage during periods without solar power. Participants also explore the potential for modifying existing freezers and the complexities involved in swapping compressors, emphasizing a phased approach to experimentation. Overall, the idea aims to develop a practical and efficient solar fridge system for off-grid users.

Oct 2, 2022

sophiecentaur

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The Bill said:

Another option is to use a nonimaging solar heat collector (maybe something similar to the evacuated glass tube collectors on solar water heaters) to power an absorption refrigerator.

I think that could be a good way to go. Absorption fridges were popular for camping because they could use gas, 12V or mains, depending on the circumstances.

But what about using a totally thermoelectric (Seebec / Peltier) system, with a solar furnace beamed onto a large area of Peltier panels (pretty cheap and modular) and some thick cable, routed round the house, to similar panels in the fridge?

The temperature of the hot source should be as high as possible, consistent with the panel not getting over-cooked (<320C or less for cheap units). That could be taken care of with a bimetal strip to defocus or deflect the incident sunlight. Efficiency could be a problem but hot weather would supply more cooling than cold - which is the right way round.

Any system with interrupted power supply could use water / ice as a thermal store but, in a static situation, a water tank wouldn't be a problem.