VARI-RO solar-powered desalting technology

This paper reports on the innovative concepts study conducted for the Middle East Desalination Research Center (MEDRC) to determine the cost-effectiveness of new approaches to solar powered desalting. These approaches include combining of modern solar power conversion technology with newly developed, hydraulic-driven, pumping and energy recovery technology for brackish water and seawater desalting reverse osmosis (BWRO or SWRO) desalting. The study included a literature search of existing methods, preliminary concepting and assessment, technical analysis, and comparisons of water produced per quantity of solar energy insolation for various concepts. The hydraulic driven pumping and energy recovery system is known as the VARI-RO system (patent pending). Four new combinations of solar energy conversion and SWRO desalting systems were evaluated for comparison to existing methods, as follows: System A, solar photovoltaic-electric module with the VARI-RO electric motor drive; System B, solar dish concentrator-Stirling engine electric module with the VARI-RO electric motor drive; System C, solar trough concentrator-thermal energy module with the VARI-RO direct drive engine. System D, solar dish concentrator-thermal energy module with the VARI-RO direct drive engine. It was determined that the VARI-RO technology is uniquely suited for use with solar power because of (1) high efficiency of the pumping and energy recovery system, (2) high efficiency of the direct drive engine system, and (3) the capability to adjust the power consumption to match the solar power variations throughout the day. This study has shown that this solar powered desalination technology can provide substantial environmental benefits in the next century by supplying needed water to remote regions without extensive infrastructure, and also by reducing the environmental emissions (including CO2) for desalting saline water sources.