The solar desiccant system, along with the solar absorption system, is a type of thermally activated cooling system (TACS). While its counterpart uses absorbed solar heat to separate and evaporate a refrigerant fluid, a desiccant system uses moist, solar-heated air to regenerate desiccants that drive off the warm water in the air. The resulting cooled air is then passed, via evaporative stages, into the house or building.
Desiccant systems, in fact, don't necessarily cool the air so much as remove all the humidity from it. This makes the air, and subsequently the building, seem cooler. Just like absorption systems, desiccant systems are still fairly rare and mainly limited to large scale projects or hot, sunny climates. They are considerable more expensive (up front) than conventional cooling techniques and usually work in conjunction with natural gas and other heat-driven cooling systems.
Solar air conditioners based on desiccant systems are more feasible on a small, residential scale because they can operate at much lower temperatures than solar absorption systems. Desiccant coolers use solar thermal energy, usually by way of rooftop solar collectors to regenerate desiccants which, through a series of evaporative steps, dry and cool ambient air.
Typically the warm, moist air is passed over desiccants, by way of a desiccant wheel, which grab the moisture from the air, effectively cooling it. Solar thermal energy is then used to regenerate, or dry out, the desiccants as the process repeats.
Despite an ability to work at lower temperatures, and a subsequent appeal for moderate climates, the spread of solar desiccant cooling continues to be limited by high up front costs and inability to carry the entire cooling load for a home. According to the National Renewable Energy Laboratory (NREL), most solar cooling systems -- be they absorption or desiccant systems -- are designed to handle 30-60% of cooling requirements, with the remainder provided by a backup heat source such as natural gas.
The following articles provide you with basic understanding of solar desiccant cooling, including the more traditional desiccant dehumidifier as well as the new wave of liquid desiccant cooling. Then find out your home's potential for solar air conditioning by connecting with solar energy contractors in your area.
Helpful information about solar air conditioning for homeowners. Get a free estimate, read recent blog entries, and get names of certified local solar energy contractors.… Read more »
Helpful information about solar cooling for homeowners. Get a free estimate, read recent blog entries, and get names of certified local solar energy contractors.… Read more »