Solar powered desalination

Despite water being apparently abundant, up to half of the world’s population is faced with water crises which is growing at an alarming rate most especially in developing countries such as African countries where both physical and economic water scarcities prevail. Thus with the abundant salty water and solar intensity in the regions or seasons when water is mostly scarce, solar powered desalination presents an attractive and promising solution towards availability of clean water. A unique and simple solar desalination system has been developed. The system which based on humidification/dehumidification process is a low cost solution and very competitive with conventional desalination systems. It can be used to provide clean water to the over one billion population who have no access or have water shortages which threaten their health and economies. The developed solar desalination system consists of a purposely designed concentrating solar collector and the desalination core which consist of the humidification and dehumidification chambers. The novel concentrating v-trough solar collector which has its focal point at the bottom of the concentrator provides enough thermal energy required to heat up seawater which is then pumped and sprayed to humidify the incoming air in the humidification chamber. The humidified air enters the dehumidification chamber and is cooled by the incoming cold seawater. The moisture is condensed out and the pure water is accumulated at the base of the chamber, and the dehumidified air is discharged to the outside. The key point is the psychrometric energy re-use, most of the energy is from the condensing of the moisture in the carrier gas. Both theoretical analysis and experimental tests were carried out and good water output up to 20kg/h and COP around 3 was obtained. This would require 8m2 of the newly designed v-trough collector operating at 100°C at 1000W/m2 solar intensity. And economic and environmental analysis showed that the solar powered desalination system can achieve a 6 year payback period when compared with when driven by electricity and also a saving of up to 4730 kgCO2 per year. The system can be manufactured from inexpensive plastics rather than exotic and expensive metals. It can easily be sized and scaled to location’s needs, can be operated in diverse geographies unattended on a continuous basis and require minimal maintenance