Report: Salt-powered air-conditioner seen to save energy

Salt may soon be used to power an air-conditioner that takes up only half the energy of conventional air-conditioners. Massachusetts-based start-up 7AC Technologies is now raising $1.3 million to build a commercial prototype of its gadget, tech site CNET reported. The CNET report said the design uses a liquid desiccant as compared to a condenser used by present air-conditioners, to remove humidity from air. By using its process, it said it can cut cooling costs by 50 to 75 percent, and heating costs by about 50 percent. CNET quoted CEO Peter Vandermeulen as saying the company has a prototype in its lab and plans to beta test it with customers next spring. Vandermeulen said they also intend to make a residential system as well. He added one of the advantages of the system is that it can operate using relatively low heat starting at only 100 degrees Fahrenheit. This means heat could come from various sources such as natural gas, solar panels, or even waste heat from a commercial building, he said. The 7AC Technologies design involves a series of flat, multi-layered plastic plates covered with a proprietary membrane licensed from the National Renewable Energy Laboratory. A solution of salt water is sprayed over the surface of the plate. As the salt solution rolls down the surface of the plates, it attracts water vapor from humid air. The salt water is then collected and passed through another set of plates which heat the solution and exhaust hot, moist air. Minus some water, the salt solution is then recirculated back toward the dehumidification plates. "It (the polypropylene membrane) is made using the same process they use to make garbage bags, except if you saw it under a microscope, the plastic sheet would look like netting," Vandermeulen said. Applications The company plans to build an air conditioner that could replace the existing systems on flat commercial rooftops. While the system is a net user of water, Vandermeulen said the on-site efficiency improvements mean that less water is used in central power generation. The company originally intended to market a system driven by heat from solar panels, which would cut the energy use even further. But it decided to focus instead on the efficient air conditioning as its core technology. "When you talk about solar, investors start to pull their Blackberries out and lose interest," he said. — LBG, GMA News