Decentralized water purification using solar thermal energy

Provision of clean drinking water to poor can prevent a large number of deaths and illnesses amongst children around the world. In 2010, about 0.75 million child deaths were caused due to diarrhea, and a further 22.5 million years of life were lost due to ill-health, disability or early death caused by unimproved water and inadequate sanitation around the world. Most of these people live in regions with limited or no electricity, and abundance of sunshine and salt water or unclean water. Solar thermal distillation using solar stills is the most potent way of cleaning the salt water in the absence of electricity. Several products, such as the inflatable stills for life rafts, water-cone and water pyramid have been demonstrated for the purification of salt water. None of these is specifically targeting a single family. We found that simple ways of natural cooling improve the production considerably. Moreover, dripping from cleaned water from the condensing area reduced the production. A simple rule could be formulated that provides an estimate of the maximum length before dripping starts. With this a more clever design of the collection of clean water allows stills of larger scale that still produce efficiently. The work of this thesis we aim at a plastic based solar stills capable of providing at least 2.5 liters/day of drinking water, an amount put forward by the UNICEF. The results are being used by Dr Ten B.V. for the development of a simple and replicable mass manufacturing process for plastic based stills. Future projects for the use of solar stills are under consideration with several governments and organizations like UNHCR.