eco cool water bottle by Vedang K. from india

The Eco-cool bottle has been designed in 3 layers. The innermost being the copper container, which shall actually hold the water. The middle layer consists of sponge made from khus (vetiver) or agricultural fiber waste and the outermost layer is a rubber sleeve. The materials for all the layers are either biodegradable or recyclable and have been chosen keeping in mind their properties.
The base of the copper container has uniformly distributed micro perforations. Water seeps through these holes into the middle layer of sponge. As per the laws of thermodynamics the seeping water will lose latent heat to the atmosphere and cool the copper container. Copper being a good conductor of heat shall transfer the temperature change to the water inside and cool it without electricity. Also copper has anti-microbial properties which prevent contamination of water.
The middle layer of khus sponge absorbs the water and retains the moisture, further enhancing the cooling process. Mats made from this sponge are drenched in water and hanged in households across India to get respite from the heat and humidity of the hot Indian summer.
The outermost layer is made up of recycled rubber with strategically placed perforations. The purpose of the sleeve is to avoid direct contact with the moist surface and provide grip while handling the bottle. All three layers can be separated periodically to clean the apparatus. The sponge layer is replaceable.
The cap of the bottle has an in built filter with a layer of alum which is a natural water purifying agent. This will enable the user to fill up water from almost any water source without being too cautious about the purity of the water.