Dual Air Conditioning – What an energy saver

Not much to say about this. Just a pretty nifty idea. I am going to put up a couple of the central paragraphs.


New Air Conditioning System Has Potential to Slash Energy Usage by Up to 90 Percent

ScienceDaily (June 21, 2010) — Ah, the cool, refreshing feel of air conditioning on a sweltering summer day.

dot dot dot (as they say)

DEVap: Liquid Desiccants, Permeable Membranes

The DEVap solves that problem. It relies on the desiccants’ capacity to create dry air using heat and evaporative coolers’ capacity to take dry air and make cold air.

“By no means is the concept novel, the idea of combining the two,” Kozubal said. “But no one has been able to come up with a practical and cost-effective way to do it.”

HVAC engineers have known for decades the value of desiccants to air conditioning. In fact, one of the pioneers of early A/C, Willis Haviland Carrier, knew of its potential, but opted to go the refrigeration route.

Most people know of desiccants as the pebble-sized handfuls that come with new shoes to keep them dry.

The kind NREL uses are syrupy liquids — highly concentrated aqueous salt solutions of lithium chloride or calcium chloride. They have a high affinity for water vapor, and can thus create very dry air.

Because of the complexity of desiccant cooling systems, they have traditionally only been used in industrial drying processes. Inventing a device simple enough for easy installation and maintenance is what has impaired desiccant cooling from entering into commercial and residential cooling markets.

To solve that problem, the NREL device uses thin membranes that simplify the process of integrating air flow, desiccants, and evaporative cooling. These result in an air conditioning system that provides superior comfort and humidity control.

The membranes in the DEVap A/C are hydrophobic, which means water tends to bead up rather than soak through the membranes. Imagine rain falling on a freshly waxed car. That property allows the membranes to control the liquid flows within the cooling core. “It’s that property that keeps the water and the desiccant separated from the air stream,” Kozubal said.

“We bring the water and liquid desiccant into DEVap’s heat-mass exchanger core,” Kozubal said. “The desiccant and evaporative cooling effect work together to create cold-dry air.”

The air is cooled and dried from a hot-humid condition to a cold and dry condition all in one step. This all happens in a fraction of a second as air flows through the DEVap air conditioner. The result is an air conditioner that controls both thermal and humidity loads.

DEVap helps the environment in many ways. DEVap uses 50 percent to 90 percent less energy than top-of-the-line refrigeration-based air conditioning.


Go there and read. More tomorrow.


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