DEVAP Technology: The Wave of the Future?

game changer1 150x150 photo (hvac green building green technology )R&D magazine has named it one of most important innovations of 2011. The U.S. Department of Energy calls it a “revolutionary technology.” We’re talking about DEVAP, or desiccant-enhanced evaporative air conditioning.

The U.S. Department of Energy reports DEVAP uses up to “90 percent less electricity and up to 80 percent less total energy than traditional air conditioning,” with an estimated payback in three years. As the MIT Technology Review explains, few inventions beat air conditioners for cooling. However, few inventions beat the air conditioner in terms of energy inefficiency. Air conditioning uses over 12% of the electricity generated in the U.S., according to the Business Insider.

More about DEVAP from Energy.gov:

DEVAP technology combines membranes, liquid desiccants and evaporative cooling together in a way that has not been done previously. The National Renewable Energy Laboratory’s (NREL) patented concept uses thin, hydrophobic membranes. With hydrophobic membranes the water beads, rather than soaks into the membranes.

This allows for greater control over the liquid flow so the water and desiccant remains separated from the air flow. The desiccant creates dry air using heat, while the evaporative cooler turns dry air into cold air; the desiccant and evaporative cooler work together to create cold-dry air.

The U.S. Department of Energy provides a full report on the DEVAP process. The Business Insider offers a simpler explanation about how DEVAP works in comparison to air conditioning: in traditional air conditioners hot air is brought into the unit, dried out and cooled. If the air is very humid, the air conditioner has to work even harder to dehumidify the air. With DEVAP, a liquid form of desiccant is used to dry out the air, making the process much more efficient.

With DEVAP the benefits are experienced on a greater level in hot, humid climates. Buildings don’t have to be over cooled, which reduces stuffiness and high humidity. And building owners should see an overall reduction in their energy bills. DEVAP technology is expected to reduce electric power demand and grid strain.

The technology uses salt solutions instead of refrigerants. The solution doesn’t contain any chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs). A traditional residential air-conditioning unit can contain as much as 13 pounds of CFCs or HCFCs; one pound of either CFCs or HCFCs contributes to global warming as much as 2,000 pounds of carbon dioxide does, according to the NREL.

The U.S. Department of Energy plans to roll out this technology in commercial markets first. The energy payback for efficient cooling is higher in commercial applications. But once the technology is established, residential use will start to increase as well.

This technology does not come without drawbacks. While the NREL claims the investment offers a significant return, the upfront costs may be expensive. Technicians will need to undergo training on the technology, and organizations such as the ACCA and HARDI will need to jump on board by offering education and training techniques for installing and maintaining DEVAP products.

In its report, the NREL says that the risks are unknown. Reliability and longevity may offer the greatest risks, as with any new technology. DEVAP must be more reliable and last longer than today’s cooling technologies to show it’s successful and that it can serve as a replacement for existing technologies.

The NREL explains that additional ductwork may be needed or a modification to the design of the system may be necessary so the system can fit into already existing construction; new construction will more easily accommodate the design/ductwork. Additionally, some areas in the United States may lack access to thermal sources such as natural gas to restore the desiccant; solar energy may be another option in these areas.

But even with this new technology, you need to remember that ongoing maintenance and repair is still very necessary. Evaporator coils will need to be cleaned. Biological growth contained, and duct work cleaned.

What are your thoughts on DEVAP as a way to handle our future cooling needs?

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