June 2008 saw the University of California Davis’ Western Cooling Challenge inauguration.  The Cooling Challenge is a program of activities designed to help cooling-unit manufacturers deliver better products, and to help building owners install and use those products in their new and existing low-rise, nonresidential buildings such as suburban retail and office buildings.

The first certified winner is Coolerado Corp. of Denver. Recent federal tests show that Coolerado’s five-ton commercial rooftop unit should be able to air-condition a typical big-box store with less than half the energy needed by conventional cooling units.

The catch is southwestern states are hot and dry, but use cooling systems that were designed for warm and more humid climates. The Cooling Challenge is based on the premise that southwestern-specific technologies should be able to cool using far less energy.

Mark Modera, director of the UC Davis Western Cooling Efficiency Center says, “Coolerado’s entry in the Western Cooling Challenge was the first to take our rigorous tests at the Advanced HVAC Lab at the U.S. Department of Energy’s National Renewable Energy Laboratory in Golden, Colo.”  The result, the Coolerado H-80 delivers a stunning near 80 percent energy-use savings and over 60 percent peak-demand reduction.  These are very big numbers.  Commercial rooftop air-conditioning units are used to cool 70 percent of the floor area in nonresidential buildings in the western U.S. In California alone air-conditioning accounts for an astounding 50 percent of the summer peak power load.  Cut that by more than half and the power generation issue changes completely.

Conventional air conditioning works by manipulating a chemical refrigerant through cycles of compression and expansion. The refrigerant absorbs heat to cool interior air and releases it to the air of the great outdoors.  That makes any confined space a candidate for being a refrigerator (at comfort levels of temperature and humidity).  Coolerado’s technology applies where the humidity issue doesn’t come into play, in arid areas that the humidity absence can be exploited.

How Coolerado Works.  Click image for more info.

How Coolerado Works. Click image for more info.

Coolerado takes an alternative method of cooling, the evaporative or swamp cooler design to a new heights of efficiency and design.  Evaporative coolers use a blower to force hot air through a water soaked pad.  The water evaporates, carrying the heat with it and the air, now carrying some of that water, is passed back into the confined space.  An indirect evaporative cooler could have a secondary heat exchanger that captures some of the humidity from the cooled air before it is returned to the temperature controlled space.

Coolerado’s air conditioners work with the same basic model as evaporative coolers, drawing fresh air into the unit with a fan where it is filtered of dust and allergens and enters into a series of Heat Mass Exchangers.  The heat mass exchangers consist of several plates of a special plastic that wicks water evenly on one wide and transfers heat through the other side.  These plates are stacked and separated by channels that guide air movement, dividing the air streams into “product air” and “working air.” Thus Coolerado has invented a new heat exchanger design using water and air.

The product air within the confined space air stays within the dry channels the entire length of the heat mass exchanger where it is cooled as it passes through and into the confined space.  The working air from the outside initially enters dry channels where it is pre-cooled, divided into multiple streams and directed into wet channels.  The heat from the product air is transferred to the working air in the wet channels by means of evaporation (mass transfer and state change) before the working air is ejected back outside.

An advantage or disadvantage from the separate airflows is the process does not add nor remove humidity to the product air.  Inside the Coolerado mass heat exchangers the heat transfer process occurs multiple times in a short physical space resulting in progressively colder product and working air temperatures.

If you’re living in an arid zone Coolerado offers two other major incentives.  Current evaporators work at about reductions of 20° F.  Coolerado’s units can drop temperatures 100° F in units measuring only 13 inches.  The energy savings are staggering.  A Coolerado system will cool the same space as the most efficient traditional AC system while using only 10 percent of the energy.  The company web site offers that a 3,000 square foot building can be cooled by a single unit using 1/3 the energy of a standard hair dryer, about 600 watts.

That suggests that a photovoltaic system wouldn’t need to be so large reducing that investment.  Moreover where adequate water is in good supply for the evaporator, a much larger share of the earth’s surface would be more pleasantly inhabitable.

The down side is that evaporator systems need cleaned of the gunk that is left behind when the water is evaporated off.  But for virtually anyone, saving up to 90% on the air conditioning electricity bill is a minor price for the effort to flush a system.

Coolerado is off the ground and products are currently available only through distributors in ten Western states.  You’ll need a small electrical service and add a water supply.  Prices are expected to be comparable to other high-end air conditioning products.

But those prices might not hold.  The Cooling Challenge has five other manufacturers promised to submit equipment for Western Cooling Challenge efficiency testing. More results should be available by the end of 2009.  These products have to be candidates for utility incentive programs, soon.

Coolerado’s CEO Mike Luby said, “Coolerado would not have taken on the big task of producing this exceptional product had it not been for the challenge laid down by the Western Cooling Efficiency Center.”  That’s something to keep in mind when destructive ideas like cap and trade are floated as “incentives.”


7 Comments so far

  1. Matt on August 18, 2009 7:17 AM

    How much water is used compared to conventional systems is the question I have.

    Most of the large industrial cooling plants already have cooling towers that drip water and sometimes give off steam. So, industrial cooling already uses water. And, power generating systems are heavy water users – that is why they have cooling lakes.

    So, if this system uses 100 gallons per hour but reduces power station uses by 100 gallons per hour – the water usage issues is a wash.

  2. Rick Gillan on August 18, 2009 9:59 AM

    You are correct Matt – Coolerado systems are ‘Net Water Neutral.’ According to the DOE, on average it takes about 2 gallons of water to produce 1 kilowatt-hour of electricity. So a traditional a/c that draws 6 kw of electricity will use 12 gallons of water at the power plant. A comparable Colerado a/c will draw about 600 watts – about 2 gallons of water at the power plant – and use about 4 gallons per hour on average at the air conditioner. That water will generally cost the consumer $20 to $30 for the whole cooling season, but will save many hundreds of dollars in electricity (not to mention saving other resources and less pollution).

    The DOE testing on this new H80 unit shows water use at 1.85 gallons per ton hour, which is less than half of the aggressive water conservation goal of 4.0 gallons per ton hour set by the UC Davis Western Cooling Challenge.

    Rick Gillan – One of Coolerado’s Founders

  3. Rick Gillan on August 18, 2009 10:03 AM

    Sorry, the last paragraph is not quite right. The DOE testing is gallons per ton hour, not gallons per hour.

  4. A New Efficient Air Conditioner | XINCA Tech Services on June 29, 2010 3:38 AM

    […] intriguing product already on the market in arid, temperate climates is the Coolerado cooler. It differs from a typical evaporative cooler by never increasing the moisture content of the supply […]

  5. Swiss Ball Exercises on November 8, 2010 9:54 AM

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  6. Curtis Tanaka on May 22, 2011 5:47 PM

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  7. Elizbeth Tommolino on September 1, 2011 9:21 AM

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