UC Davis, SMUD pursue a better air conditioner

In this challenge there is no prize, but there could be a big payoff for big box retailers, utilities and air conditioner manufacturers.

It's called the "Western Cooling Challenge" in which University of California, Davis, researchers have enlisted cooling system manufacturers to build a better air conditioner.

Or, at least tweak and add components to the ones we have. If it can be done, the payoff for owners of small and large buildings could be huge.

A typical Sacramento big box retailer uses 50,000 more kilowatt-hours in July than in December.

"That is mostly due to air conditioning," said Jim Parks, Sacramento Municipal Utility District energy efficiency manager. "At an average of 10 cents a kilowatt-hour that equals an additional $5,000."

For a utility, more efficient air conditioners could mean not having to provide as much peak demand electricity.

So, SMUD is supporting the UC Davis challenge to develop a hot and dry climate air conditioner.

Westerners use a form of air conditioning based on weather conditions in the East and Southeast.

Researchers at UC Davis' Western Cooling Efficiency Center figured if a better air conditioner could be designed for Western conditions, they could save a lot of energy.

"There are two things different about the climate in the West," said Mark P. Modera, director of the center. "There is much lower humidity and there are bigger day and night temperature swings."

UC Davis recently provided manufacturers with an ambitious timeline to field test the new air conditioners next summer.

The long-term goal of the Western Cooling Efficiency Center is to reduce energy used in 11 Western states with dry summer climates: California, Arizona, Nevada, Utah, Colorado, Oregon, Washington, Idaho, Montana, Wyoming and New Mexico.

Technology in the new cooling units could include a combination of traditional refrigerated air conditioner technology and "indirect evaporative cooling."

"When you evaporate water it cools," said Modera. "In Arizona and in California you had swamp coolers. Those are direct evaporative: you blow air into your house and you evaporate water into the air and that cools it down."

However, on the hottest days of the year, swamp coolers are often not enough.

So technology called "indirect evaporative air conditioning" has been developed. In that technology, a heat exchanger is used to capture the cooling provided by the evaporated water and thereby improve evaporative cooling performance.

A combination of the refrigerative and indirect evaporative air conditioning should be more energy efficient than strictly the conventional refrigerative air conditioning alone, said Modera.

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