The design is simple and anyone can make it. Depending on your requirements you can increase or decrease the size. Build two enclosing structures with a gap of 7.5 cm. Fill this gap with sand and keep the sand wet so that the moisture can be maintained. Keep the fruits and vegetables in air crossing crates in the chamber and cover them with polythene sheet. Spread the straw and gunny bags on the chamber and keep them wet. The internal temperature of the chamber will be 10-15 °C lower than the outside temperature. On an average 90 % moisture is maintained inside.
This chamber is not dependent on fossil fuels or electricity, so while the farmers reap the benefits of it being zero energy, it is Eco-friendly as well.