It’s a fast race to green up our lives and our society. In fact, it has become more like a mission. With all that running from this CFL to that Energy Star dishwasher, we work up quite the proverbial sweat. Ironically, our answer to space cooling (usually via an air conditioner) is one of the least-green household appliances, sucking away at our fossil-fueled electricity nearly constantly and at an alarming rate. Yes there are Energy Star air conditioners, which greatly reduce energy usage, but these do little to curb our need for grid electricity. What if we could replace our need for conventional cooling systems?
The technology is certainly there but it is still young and uncompetitive. Nonetheless, it’s fascinating. Imagine using solar heat to cool your house! Well you can do it right now, as long as you’re willing to fork out some serious extra cash. While solar space cooling and other thermally activated cooling systems (TACS) are an excellently green option, they are still too expensive and require too much heat to be economically viable for most homeowners. The best place you’ll find them now is in a large scale setting, where they only provide 30 to 60% of cooling needs.
Still the need for energy independence and lower costs are driving technologies forward. As of right now there are two types of solar cooling systems: absorption and desiccant systems.
Solar absorption systems use refrigerant and absorbent fluids. The refrigerant (usually water) and an absorbent (lithium bromide salt, say) are separated using solar thermal energy. That refrigerant, now water vapor, is then condensed into chilled water and used to cool air flowing into the building.
Solar desiccant systems use desiccants, such as silica gel or calcium sulfate, to suck the humidity out of warm air, thus cooling it. Via separate evaporative stages, the air is cooled and then passed into the building.
Solar space cooling is a possible if yet unlikely green solution for the home. Perhaps combined with more efficient and inexpensive solar hot water or space heating systems, solar space cooling could become competitive in the marketplace. In hotter climates, such as the American Southwest, solar space cooling shows much more promise because of the high constancy of sunlight available which is required for solar cooling systems to function properly.
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Renee Rutledge writes for CalFinder Solar, the source for Residential Solar Power installation experts.
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