Solar Humidification
Encyclopedia
The solar humidification-dehumidification method (HDH) is a thermal water desalination method. It is based on evaporation
of sea water or brackish water
and consecutive condensation
of the generated humid air, mostly at ambient pressure. This process mimics the natural water cycle
, but over a much shorter time frame.
The simplest configuration is implemented in the solar still
, evaporating the sea water inside a glass covered box and condensing the water vapor on the lower side of the glass cover. More sophisticated designs separate the solar heat gain section from the evaporation-condensation chamber. An optimized design comprises separated evaporation and condensation sections. A significant part of the heat consumed for evaporation can be regained during condensation. An example for such an optimized thermal desalination cycle is the multiple-effect humidification (MEH) method of transportation.
Solar humidification takes place in every greenhouse. Water evaporates from the surfaces of soil, water and plants because of thermal input. In this way the humidification process is naturally integrated within the architecture of the greenhouse. Several companies like Seawater greenhouse
utilize this inherent feature of a greenhouse in order to conduct desalination inside the atmosphere of the facility.
This integrated biotectural system
mimics the natural process of cloud formation respectively desalination exactly.
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
of sea water or brackish water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...
and consecutive condensation
Condensation
Condensation is the change of the physical state of matter from gaseous phase into liquid phase, and is the reverse of vaporization. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition....
of the generated humid air, mostly at ambient pressure. This process mimics the natural water cycle
Water cycle
The water cycle, also known as the hydrologic cycle or H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapor, and solid at various places in the water cycle...
, but over a much shorter time frame.
The simplest configuration is implemented in the solar still
Solar still
A solar still is a low-tech way of distilling water, powered by the heat of the sun . Two basic types of solar stills are box and pit stills. In a solar still, impure water is contained outside the collector, where it is evaporated by sunlight shining through clear plastic...
, evaporating the sea water inside a glass covered box and condensing the water vapor on the lower side of the glass cover. More sophisticated designs separate the solar heat gain section from the evaporation-condensation chamber. An optimized design comprises separated evaporation and condensation sections. A significant part of the heat consumed for evaporation can be regained during condensation. An example for such an optimized thermal desalination cycle is the multiple-effect humidification (MEH) method of transportation.
Solar humidification takes place in every greenhouse. Water evaporates from the surfaces of soil, water and plants because of thermal input. In this way the humidification process is naturally integrated within the architecture of the greenhouse. Several companies like Seawater greenhouse
Seawater Greenhouse
The Seawater Greenhouse is a technology that enables the growth of crops in arid regions, using a greenhouse structure, seawater and solar energy...
utilize this inherent feature of a greenhouse in order to conduct desalination inside the atmosphere of the facility.
This integrated biotectural system
Integrated biotectural system
An integrated biotectural system is a system which integrates natural and architectural elements. It can include desalination of sea water....
mimics the natural process of cloud formation respectively desalination exactly.
External links
- Encyclopedia of Desalination and Water Resources
- The MEH-Method (in German with English abstract): Solar Desalination using the MEH method, Diss. Technical University of Munich
- Desalination Systems using the MEH-Process