In developing countries millions of middleclass people cannot afford to pay the high electricity bill to run the room A.C. during hot weather. The A.C. is critical while sleeping. The room A.C. cools whole volume of the room whereas volume of human body is a minute % of whole room.
So cooling the entire room is wasteful of energy. In addition to this, generally rooms are not properly insulated. Due to these reason room A.C. has to work hard. If these wastages are eliminated then cooling power requirement is vastly reduced. Kool Kot is a small A.C. that is installed at the leg side of the bed. Due to small volume to cool, the electrical power requirement is less than 25% of normal room AC. Two people can sleep at Air Conditioned comfort
Solar Earth Economical Cold Storage ( SEEKS )
In the developing countries a small farmer cannot afford a Cold Storage installed at his farm. It is expensive to own and operate. But a Cold Storage greatly enhances a small farmer finances. For example, if he waited a week or two to sell the Tomato when prices are high he could have realized a a hefty profit. But without a cold storage to store he is compelled to sell his produce even when the prices are down.
In the hot ambient temperature when the Sun is hitting on the roof of a over ground cold storage the total heat load is enormous. It requires lot of cooling power. Also, for a small farmer the land area is at premium. If he builds a Cold Storage above ground then he loses that much land area.
The smart thing to do is build a cold storage underground. This saves the land area. Most importantly the temperature 6 feet underground is constant between 20 to 24 C, even in hot Summer. The heat load is considerably reduced. Also building an expensive insulated building above ground is avoided. The Cold Storage built underground receives lesser heat infiltration. This can be cooled by using 100% Solar Power. No need of electricity supplied by unreliable Utility Company.