This type of fridge does not rely on electricity or modern refrigeration technology but rather on the principles of evaporative cooling and the use of earthen materials. It is also known as a “clay pot refrigerator” or a “zeer pot.” Here’s how it works and some of its characteristics:

How an Earthen Fridge (Zeer Pot) Works:

1. Materials: An earthen fridge is constructed using two clay pots, one smaller and placed inside the other. The space between the two pots is filled with sand or soil.
2. Evaporative Cooling: The inner pot is used for storing perishable items, such as fruits, vegetables, or dairy products. The space between the pots is kept moist, and a wet cloth or lid is often placed over the top. As the water in the sand or soil evaporates, it draws heat from the interior of the inner pot, effectively cooling the contents.
3. Cooling Effect: The evaporative cooling process creates a lower temperature inside the inner pot, allowing the stored food to remain cooler than the surrounding environment. This can help prolong the freshness of food items.

Key Characteristics and Uses:

1. Off-Grid Cooling: Earthen fridges are particularly useful in areas where a reliable electricity supply is scarce or unavailable. They offer a practical and low-cost solution for keeping food items cool without the need for electricity.
2. Food Preservation: These cooling devices are often used by rural households, farmers, and communities to preserve fruits, vegetables, dairy products, and other perishables for longer periods. They can help reduce food waste.
3. Eco-Friendly: Earthen fridges are environmentally friendly, as they don’t rely on electricity or refrigerants that can harm the environment. They use minimal resources and are sustainable.
4. Sustainability: These fridges are easy to construct and maintain, making them a sustainable and cost-effective solution for cooling food in regions with limited resources.
5. Simple Design: The design is straightforward, using readily available materials, which makes it accessible to a wide range of people.

It’s important to note that the cooling effect of an earthen fridge is not as intense as that of traditional electric refrigerators, and they are most effective in arid or dry climates where evaporative cooling is more efficient. In very humid conditions, their cooling effect may be less pronounced.