Catching up with energy-efficient cooling systems: Coolerado

A solar array provides power for the Coolerado air conditioner, and the cool exhaust stream from the Coolerado improves the performance of the solar panels. (Photo by Coolerado)

Cooling season is fast approaching—in some parts of Western's territory, it's already here—so it is a good time to revisit two promising, energy-efficient, cooling technologies that could help utilities control this rapidly growing summer load. This month, Energy Services Bulletin looks at the Coolerado, which last appeared in the June 2005 issue. 

Since its introduction five years ago, the Coolorado has evolved, gained wider acceptance and earned recognition. In late January, the Colorado Governor's Energy Office presented the Denver-based Coolerado Corp. with the Governor’s Excellence in Renewable Energy Award. The award recognized Coolerado for developing a solar-powered mobile air conditioner, "The closest thing to free air conditioning," as Coolerado Executive Vice President Rick Gillan described it. 

Not typical evaporative cooler

Although the company refers to its equipment as an air conditioner, the system represents very different technologies. Utilities should take that into account when considering equipment for a rebate program, or recommending a particular technology to a customer.

The Coolerado, a type of indirect evaporative cooling system, can take the place of conventional air conditioners in most applications, especially in dry and semi-humid climates. Direct "swamp" coolers add moisture to cool an air stream, making it unsuitable for humid climates. In the indirect process, the air does not come in contact with water, but the temperature of the delivered air is typically warmer than a swamp cooler.  

The Federal Energy Management Program described Coolerado as an ultra-cooler because its indirect evaporative process cools to significantly lower temperatures than a swamp cooler can, without adding humidity. A heat and mass exchanger (HMX) cools the air instead of water, as in a swamp cooler, or refrigerant and compressors, as in an air conditioner. The result is air-conditioner temperatures for about 15 percent of the electricity an air conditioner would use.

Improving a good product

Responding to growing concern about the environment and ever more volatile energy prices, Coolerado has made improvements in the first generation cooler and is working on new products.

In the new R600 unit, the original cellulose HMX has been replaced with an all-plastic component. The plastic HMX increases air flow to get lower temperatures, so the same size unit provides more cooling than the previous generation. "It delivers 5 tons of cooling for just 600 watts, and it lasts 10 to 15 years," Gillan said.

Sacramento Municipal Utility District, in its fifth year of field-testing the technology, installed the new HMX in one of its seven Coolerados, and has since ordered the plastic components for the other units. "There was a big pressure drop in fan energy across the cellulose HMX, so the plastic one is definitely an improvement," said Dave Bisbee, project manager for SMUD's Customer Advanced Technologies program.

Bisbee also likes the redesigned water controls that regulate the Coolerado's water use based on outside temperature. "Water use is a big concern," admitted Bisbee. "Before SMUD offers rebates for these types of systems, we want to be sure that the products use water efficiently, too."

Reaching new audiences

Last year, a grant from GEO to build a solar-powered mobile demonstration cooler brought Coolerado to the attention of a broader audience. The unit is outfitted with four PV panels to power the cooler, and the cooler "returns the favor" to the solar array. A duct from the cooler directs the cool, saturated exhaust air behind two of the solar panels. The ducted and un-ducted panels are separately metered to show how the Coolerado exhaust air can actually improve the performance of its own distributed power source by more than 15 percent. The company demonstrated the mobile unit first at the Mile Hi Music Fest, and then at the Democratic National Convention. 

Although Coolerado is expanding its manufacturing capacity, Gillan said the company does not plan to build PV-powered coolers. "Air conditioning installation and solar construction are two different skill sets," he explained. "We would rather work with AC and PV contractors, and encourage them to work together. That will get more units out to consumers."

To reach contractors, consumers and anyone else who wants to learn more about this proprietary technology, Coolerado produced a series of videos and posted them on YouTube. An introduction video and Coolerado Air Conditioning Basics II have received about 600 hits each. The solar demonstration video has been viewed more than 4,000 times, thanks in part to the mobile unit's high profile.

Cooling the West

SMUD continues to test its Coolerados, while Public Service Company of New Mexico already offers an incentive for the unit and Xcel in Denver may follow soon.  Since the beginning of the year, Coolerado has signed agreements with new distributors and salespeople to pitch the cooling unit to builders and commercial property owners across the western United States.

In anticipation of those orders, and to handle the interest generated by the solar demonstration, Coolerado recently relocated to a larger manufacturing facility and is adding employees. And improvements keep coming: the company is working on an M50 modular system that can be stacked to build a larger airflow for cooling bigger facilities.

Coolerado also has built a commercial roof top air conditioner as an entry in the Western Cooling Challenge, held by the Western Cooling Efficiency Center at University of California-Davis. The competition judges commercial rooftop units designed to reduce cooling system electrical demand and energy consumption in the Western United States, "Where we don’t need to dehumidify our air," noted Gillan.

Most air conditioning standards, he added, are based on one type of equipment for all climates. With cooling systems, as with all energy-efficient equipment, there is not "one size fits all" answer. Consumers—and utilities—need to look at all the options, as well as the big picture, to make the right decision.

Next month, Energy Services Bulletin highlights new developments with the Ice Bear.

Resources

Coolerado

Colorado Governor's Energy Office

Sacramento Municipal Utility District

Coolerado Air Conditioner Introduction

Coolerado Air Conditioning Basics II

Coolerado Solar Powered Air Conditioning Demonstrator

Public Service Company of New Mexico

Xcel

Western Cooling Challenge

People

Rick Gillan

David Bisbee

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Energy Services Bulletin, April 2006
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