Ever consider a waterfall in the living room? I thought not. But there are very good reasons to consider one. If you live in a hot and muggy climate and want to build a new house that is naturally comfortable and energy efficient, this is one simple and carbon neutral way to do it.
Normally, flowing water does not take moisture out of the air. But add just one ingredient to your indoor waterfall and, presto; cool dry air is made from hot and muggy air.
The secret ingredient is calcium chloride added to the water. Calcium chloride, a salt, is a desiccant, just like table salt and the grain of rice that you put in the shaker to keep it flowing freely. It is hygroscopic, meaning it attracts water molecules from the air by absorption or adsorption.
This liquid desiccant system is a wet flowing feature that can suck the moisture out of your indoor air using almost no energy. The water wall idea was first used by University of Maryland students to turn a functional mechanism into an aesthetic feature in their LEAF House in the DOE Solar Decathlon. To recycle the desiccant, the water is evaporated, re-concentrating the salts to pull more moisture from the air in its next cycle. To keep energy costs low, they used solar hot water heaters for the evaporation cycle. Then once the desiccant is concentrated again, it is ready to do more work pulling water out of the air.
These systems have been used in the commercial and manufacturing sector for many years. Complex piping in commercial buildings (running on carbon heavy fossil fuels) also use desiccant systems to remove mold growth and other consequences of moist air.
Desiccant use in commercial A/C systems is not a lovely thing. A waterfall is. And it is a very planet friendly low carbon cooling system.
Image from Flikr user BamaWester
Cooling Your Living Room With a Water Wall
September 25, 2009 by uadream