Hybrid solar desalination system

Abstract

A hydro-thermal exchange unit (HTEU) for desalinating feed water in accordance with a humidification-dehumidification includes feed water, fresh water and gas conduit circuits for transporting feed water, fresh water, and gas, respectively. The unit also includes an evaporator through which a portion of the feed water conduit and the gas conduit pass. The evaporator causes evaporation of a portion of the feed water to produce vapor that is transported through the gas conduit. The unit also includes a condenser through which a portion of the gas conduit and the fresh water conduit pass. The condenser has input and output ports for coupling the gas and fresh water conduit circuits. The condenser extracts moisture from the vapor transported therethrough by the gas conduit. The extracted moisture is discharged through the fresh water conduit. The unit also includes a heat exchanger through which a portion of the fresh water conduit and the feed water conduit pass to thereby extract residual heat from the fresh water such that the residual heat heats the feed water.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to a method and apparatus for water desalination using renewable solar energy.BACKGROUND OF THE INVENTION[0002]Fresh water has become a very valuable and scarce resource in recent years not only in arid countries of the Middle East and North Africa regions, but also in many highly populated areas of more developed countries, such as Spain, USA, China and many others. Increases in population and commercial activities have contributed to the depletion of freshwater resources. Desalination, as one of the earliest forms of water production, remains a popular method of water production throughout the world. Desalination typically uses a large amount of energy to remove a portion of pure water from a salt water source. Salt water (feed water) is fed into the process, the result of which is one output stream of pure (fresh) water and another stream of waste water with high salt concentration (brine). Large commercial desal...

AI Technical Summary

Problems solved by technology

However, people in many other areas of the world have neither the money nor oil resources to allow them to produce water in a similar manner.

Over a billion people today lack access to purified drinking water and the vast majority of these people live in rural areas, where it is very difficult to implement any traditional clean water solution.

The main drawback with the use of solar energy in existing large-scale desalination plants is the resulting low productivity rate and thermal efficiency.

However, since solar desalination plants use free energy and therefore have insignificant operational costs, over the long term they are more attractive than conventional approaches.

In addition to cost considerations, there are also environmental concerns about the fossil fuel burning.

The low production rate is caused by a low operating temperature and near atmospheric pressure of a resulting steam.

One of the problems that negatively influence the still performance is the direct contact between the collector and the saline water, which may lead to corrosion and scaling in the still.

The biggest issue for the solar stills however are their rather low efficiency and water production rate: a typical production rate of a solar still is about 4 L / m2 / day or less.

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