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Earth Power

New Air Conditioner Process Cuts Energy Use 50-90% 445

Posted by kdawson
from the tortured-backronym dept.
necro81 writes "The US National Renewable Energy Laboratory has announced that it has developed a new method for air conditioning that reduces energy use by 50-90%. The DEVap system (Desiccant-Enhanced eVaporative air conditioner) cools air using evaporative cooling, which is not new, but combines the process with a liquid dessicant for pulling the water vapor out of the cooled air stream. The liquid dessicant, a very strong aqueous solution of lithium chloride or sodium chloride, is separated from the air stream by a permeable hydrophobic membrane. Heat is later used to evaporate water vapor back out — heat that can come from a variety of sources such as solar or natural gas. The dessicants are, compared to typical refrigerants like HCFCs, relatively benign on the environment."
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New Air Conditioner Process Cuts Energy Use 50-90%

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  • by CAIMLAS (41445) on Monday June 21, 2010 @04:41AM (#32638266) Homepage

    So when will we be able to buy one of these? I know my wife is going to be asking for an AC in the house this summer, and I'm sure that the people in places like AZ, NM, and TX will be clamoring to lower their electric bill.

    Additionally, will the dessicants (or the filter) have a recycle lifespan, or will it be more like a traditional household AC, using a 'simple' radiator device?

  • by Anonymous Coward on Monday June 21, 2010 @05:02AM (#32638352)

    For starters, Americans should start insulating their houses better. That would cut the energy costs even more.

  • by PrinceAshitaka (562972) on Monday June 21, 2010 @05:04AM (#32638358) Homepage
    And otherr refridgerants like R-134a can also form deadly compounts when the degrade, but since they are in a closed system they can be used. I don't think the researchers anticipated tha eventuality that somone would open up one of thier units and drink the liquid inside.
  • by Chrisq (894406) on Monday June 21, 2010 @05:23AM (#32638436)

    I lost interest at this point. Wake me up when biochemists and medical doctors get a chance to run test case groups about the adverse effects of lithium in their localized atmosphere, typically inhaled into the lungs and later causing one's sense of reality to become skewed.

    Well what about the Sodium Chloride option. People have lived near oceans without adverse effects.

  • by Trepidity (597) <delirium-slashdo ... org minus author> on Monday June 21, 2010 @05:34AM (#32638496)

    From what they claim, it sounds like pairing with the desiccants will allow it to work better in humid climates, so presumably that'd have some benefit for places that are hot, humid, and have plentiful water. They do mention being able to improve the usefulness of evaporative coolers in Tucson, though (by allowing for cooling to lower temps), so you might be right about it trading one environmental ill for another.

  • It's not either/or (Score:3, Insightful)

    by stomv (80392) on Monday June 21, 2010 @05:36AM (#32638504) Homepage

    If you're building new, modern building codes result in a more insulated space. In my opinion modern codes -- even those in CA or the "stretch in MA or the base points in LEED -- aren't aggressive enough, but they're far better than existing conditions in most buildings. Of course, the same opportunities exist for major remodeling or work on the exterior.

    Sometimes, though, the mechanical unit needs to be replaced, and quickly. In those cases, would you prefer that this new AC not exist (assuming they work out any chemical safety issues)? For spaces which are currently being used, the interruptions caused by upgrading the building envelope may be intolerable, a non-starter. In those cases, would you rather this new AC not exist?

    You're absolutely right -- improving the insulation and air-sealing of our building stock would have a remarkable impact on our energy use. Still, this new AC system, if it works as advertised, can be applied to buildings for which an insulation and air-sealing upgrade simply isn't in the cards in the near term.

    Adding another tool to the belt isn't a bad thing, as long as we continue to use the right tool for the job. Building codes will help ensure that we do.

  • by Anonymous Coward on Monday June 21, 2010 @06:23AM (#32638714)

    "Sir, are you aware you were going 120 in a 30 zone?"

    "Yeah, but I saw someone who was going 130!"

  • by Pax681 (1002592) on Monday June 21, 2010 @06:30AM (#32638738)

    Finally ... a CPU that can cool itself. No noisy heatsink required!

    heatsinks are NOT noisy....... not one bit

    fans can be tho

  • by Anonymous Coward on Monday June 21, 2010 @07:18AM (#32638914)

    Any Japanese woman will tell you that insulating a Japanese house is impossible, because any attempt to do so will ensure that mould infests the house as soon as summer comes around.

    Given the large fraction of Japanese homemakers who have never experienced a summer in a foreign home and the fact that the Japanese power giants are happily selling electricity at near double the US rate, don't expect this mentality to change anytime soon.

  • by smpoole7 (1467717) on Monday June 21, 2010 @07:48AM (#32639098) Homepage

    > The places that have water to spare also have humidity ...

    It's like that here in Alabama. We're currently running in the mid-90's with dewpoints in 80's. "Swamp coolers" just don't work well in this climate, so I don't know how useful this will be to us.

    From the Wiki article on evaporative cooling: "When considering water evaporating into air, the wet-bulb temperature, as compared to the air's dry-bulb temperature, is a measure of the potential for evaporative cooling. The greater the difference between the two temperatures, the greater the evaporative cooling effect. When the temperatures are the same, no net evaporation of water in air occurs, thus there is no cooling effect."

    This is simple physics.

    In other words, it's a neat idea that'll probably work in Arizona and Utah, as others have mentioned, but where AC is used the most -- here in the humid Southern states -- evaporative cooling just doesn't work.

    Not that I wouldn't like to see it, mind you, considering the electric bills at our studios and transmitter sites. :(

  • by mprinkey (1434) on Monday June 21, 2010 @08:23AM (#32639264)

    Your argument is bogus. R30 fiberglass bats are 9 1/2 inches thick. Are you saying to frame the walls with 2x10s. You know the cost of dimensional lumber increases geometrically with dimension, right. Or do you stagger frame with 2x6s...basically build each wall twice and double your labor costs?

    What about existing structures? Because the US market has enough backlog of existing structures. Do you build another layer of insulation INSIDE the house and lose a foot of floorspace near each exterior wall..and then pay to reframe, drywall, move out electrical outlets, etc? Or do you reframe the exterior of the house and then cover and weatherize your new outside envelope?

    In either case, what about windows and doors? You do know that heat will gladly take a parallel path. Third-year ME heat transfer class...remember the resistor analogy? You can make the walls R300 and the heat will still get in (out) through "holes in the bucket." Have you priced super high R glazing options? Do you want a 8" thick front door? Even in the walls themselves, you have to worry about thermal bridging through the wood studs...all these would be problems even with some crazy aerogel insulation that is R50/inch.

    The building standard is what it is for a reason. It is an engineering trade-off between cost and performance. R30 in the ceiling and either 2x6 walls with R18 or 2x4 walls with R11-12...and maybe a dense insulation board on the outside before siding is installed. Double pane insulated glass windows. Now those trade-offs were in considered with energy and HVAC hardware costs at a certainly level. And more insulation is good but only to the point. The insulation costs goes well beyond the price of the insulation bat, and a point exists where adding more makes no financial sense. If you *insist* on having windows and doors, it doesn't make engineering sense anymore either. Your recommendation is well past that and smacks of niavete. Build or remodel a house or two (especially using your OWN MONEY) and then get back to me. A home built to your bogus specifications would cost four or five times more. I doubt you could find someone to build it for you.

    If you want to look into green houses, then look into earth bearmed homes, rammed earth homes...building underground, using lots and lots of earth as thermal insulation and thermal mass. Folks have been doing this since the 70s and there are books that give some good overviews. I'd like to see the building codes revised to make it easier to build some of these different "hippie" houses.

    And in sunny climates, I think the best ROI would be a 100x100 white canvas tarp and support structure to shade your entire house. I'm surprised no one does that. That would effectively remove the direct radiation load from the cooling...which is significant...just ask your barefeet after a walk across sunlit asphalt.

  • by Lumpy (12016) on Monday June 21, 2010 @08:34AM (#32639352) Homepage

    People in those climates would do well to force the builder to actually build the home right. Heat chimneys and long overhangs coupled with highly insulated homes and thermal masses would do a LOT to cool the home with very little cost.

    Problem is most homes are built wrong. the same damn cookie cutter McMansions that are designed by idiot architects.

    get a 20 SEER rating AC unit and you will have the most efficient you can get today... it's only a couple grand more than a standard AC unit.

    Oh and insulate your home, replace your windows with triple pane and low-e glass, and get rid of all air leaks.

  • by Hijacked Public (999535) on Monday June 21, 2010 @09:17AM (#32639784)

    When I was young we had no AC, and this was in rural southern Africa, so it was usually very warm during the day.

    I live in an old farm house in the US now and though it has central AC I very seldom use it. Usually when I have guests because if I don't they immediately comment on how hot it is and how can I stand it and that they are sweating just standing still. They threaten to swoon. They forecast their own death. They google map the closest hotel.

    I built a cabin on the other end of the property and it is similar to what you describe. (it is a Kundig [olsonkundi...itects.com] design, which tend to be pretty green) People who visit still complain when the AC is not on, but only when it is particularly hot and humid outside.

    Anyway, I think it is a combination of dwelling design and the fact that people in the US are so used to conditioned indoor air. Even at 90F there is little real physical risk to anyone other than the elderly, but I have met plenty of people who simply can't tolerate it mentally.

  • by Stoutlimb (143245) on Monday June 21, 2010 @09:29AM (#32639912)

    As a home designer, I resent that remark.

    Seeing as I lived and breathed in that field, I can tell you that just about every architect or designer gets a excited at the idea of sustainable, high energy efficient homes, built right to suit the local environment. So these "idiot architects" you rave about don't exist. Since you're obviously ignorant, let me inform you of the real problem. The general public.

    Anything other than a "McMansion" just won't sell to the vast majority of Americans. When the home buyer has a limited budget, they have to balance their wants with their needs, and often you will find that features such as low e windows, good insulation, large overhangs, large thermal mass, etc... They might not always compete when compared to that extra bedroom, the outdoor jacuzzi the wife's always wanted, or that extra bay in the garage. Saving $25 a month on a heating bill may be a priority, but in the big picture, it's rarely priority #1.

    Personally I love the idea of efficient and sustainable homes, but for one reason or another, clients who are willing to pay for that kind of thing are rare.

  • by chrysrobyn (106763) on Monday June 21, 2010 @09:49AM (#32640142)

    1) it can use salty water. It's drinking water that we are short on.

    Why do you believe it can use salty water? I've seen salt deposits, and I've worked with swamp coolers. If you spray salt water at a fiber mesh and force air through this mesh to evaporate the water and cool/humidify the air, the salt remains in the mesh, right? So it's eventually so clogged no air goes through? And the salt that makes it into the air will rust out the motor driving the fan and end up depositing itself all over your ducts and house. I'd bet you'd need to replace your swamp cooler mesh every few weeks or even every month, replace the motor annually, and if you had any metal in your ducts, they'd not be worth anything after a few years. And that's ignoring the effects of salt deposits all over your home.

  • by laughingskeptic (1004414) on Monday June 21, 2010 @10:37AM (#32640800)
    "NREL has patented the DEVap concept ... Eventually, NREL will license the technology to industry"

    I thought that inventions that we all paid for with our taxes were public domain. How is it that this government lab will be licensing this technology?
  • by danlip (737336) on Monday June 21, 2010 @12:02PM (#32642186)

    As a home designer, I resent that remark. ... these "idiot architects" you rave about don't exist.

    I believe that would be "rant", and they do exist. Until recently I lived in a house that was designed like a solar oven.
    The south face had a front porch with a dark roof which was positioned underneath the second floor windows.
    It heated the air which would then blow in through the windows. That's nothing if not stupid.
    And absolutely no overhangs (which not only is a problem because of the solar heating,
    it means you can never leave your windows open if there is even a slight chance of rain
    because your house will flood). And that house was originally built by the architect for themselves.

    I am sure the market pressures you refer to have an effect, but I think a large part of the effect is producing a
    generation of idiot home designers. 100 years ago no one would have ever designed a home like that.

  • by adonoman (624929) on Monday June 21, 2010 @12:06PM (#32642248)
    It's all what you're used to. I'm one of those people who I'm sure would be quite incapacitated by a southern US summer. If it's warmer than 80F at night, I wake up after about an hour drenched in sweat. Fortunately we get maybe one of those nights per year. We'll crack 90 maybe 5-10 times. So living without AC here, just means that I just take a couple days off work and hit the beach instead of trying to think in the heat.

    On the other hand we regularly have 2 weeks worth of -40 as daily highs. Over most of the winter I generally only heating the house to 55. At 60F I'm comfortable in a t-shirt and jeans. When my formerly Trinidadian uncle comes and visits, he keeps his huge down parka on the whole time he's here. And the African immigrants I know here have seem to enjoy having their apartments heated to 80F.

    So yes, it's all fun to be able to handle more extreme weather than others, but be careful in thinking that others are wimps. I don't know you, so I won't make any assumptions, but people who can handle heat well, often can't handle the cold (and vice versa).

  • by Anonymous Coward on Monday June 21, 2010 @01:20PM (#32643238)

    What was the humidity there?

    Using the humidex, I live in one of the hottest places in North America, often it ends up beating the humidex adjusted temperatures for places like Death Valley.

    Yet I live in Southern Ontario, traditionally considered one of the coldest places.

    Today it's an average "cooler" summer day at 24 C, with a humidex of 28 C. This Saturday it will be 28 C, with a humidex of probably around 35 C. The record temperature for today was 33 C, which would put the humidex around 44 C.

    Anything above 40 C is to be considered life threatening, if you ask your doctor. Most people (including people who are "used" to the heat) will be very uncomfortable at anything above 30 C. Your body is SUPPOSED to feel uncomfortable at those apparent temperatures, because it's trying to tell you that you will soon risk your life if you don't do something about it.

    People are used to dry(er) air, and have colonized places that aren't.

  • by Anonymous Coward on Monday June 21, 2010 @02:34PM (#32644186)
    And it dry the liquid desiccant out using free energy. At least the energy required is not accounted for in the 50-90% savings.

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