How to Build a Solar Refrigerator

Jacob Stover

Solar refrigeration is a novel form of refrigeration that uses heat and energy from the sun to create a cold environment. These solar refrigerators work by exploiting energy exchanges that occur when certain compounds turn from a liquid into a vapor, and vice versa.

Solar refrigeration requires no electricity, and no freon, a dangerous refrigerant. In the past these units had to be quite large in order to offer a level of cooling that was valuable for food storage, but new designs have emerged that are small and easy to make with just a few planting pots.

  1. Fill the larger flowerpot with a layer of sand. Ensure that there are no holes or gaps in the bottom of either pot; you can use cork or clay to plug any holes.

  2. Place the smaller pot inside the larger pot, and level the sand inside until both pots are at an even height.

  3. Fill the remaining open area between the pots with sand.

  4. Pour water into the sand to saturate it completely. Once water begins welling up instead of soaking in, you can stop.

  5. Place any items you wish to keep refrigerated inside of the smaller pot.

  6. Dampen your washcloth and lay it across the top of the pots so that they are fully covered.

  7. Return to your solar refrigerator once or twice each day to refill the sand with water and dampen the washcloth. Keep the solar refrigerator in a dry area with good ventilation. Your solar refrigerator is now complete. The method of action that allows it to remain cool is the evaporation of the water surrounding the smaller pot. As the water evaporates, heat draws out from the smaller pot, keeping the contents inside much cooler than the surrounding environment.