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Earth Power

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

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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  • Well... (Score:5, Funny)

    by Errol backfiring ( 1280012 ) on Monday June 21, 2010 @04:34AM (#32638242) Journal
    It's cheaper than using trained hydrophobes. Or are they used to create the membrane?
    • Re:Well... (Score:5, Funny)

      by elrous0 ( 869638 ) * on Monday June 21, 2010 @09:07AM (#32639692)
      I'm just worried that some of that sodium chloride will end up polluting our oceans and in our food.
  • 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 @05:24AM (#32638444)

      I know my wife is going to be asking for an AC in the house this summer

      Really? Another one? I've been visiting her for months.

    • by stonewallred ( 1465497 ) on Monday June 21, 2010 @07:10AM (#32638888)
      AZ and NM use a lot of swamp coolers if they can't afford AC. With 100 degree 0% RH, a swamp coolers does a decent job.
    • 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 Hognoxious ( 631665 ) on Monday June 21, 2010 @08:58AM (#32639576) Homepage Journal

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

        Indeed. I would highly recommend that you seal your house 100% hermetically.

        • Re: (Score:3, Funny)

          by elrous0 ( 869638 ) *
          Funny you should mention that. I had mine finished just today. I'm so excited about it that I'm feeling a bit light-headed. Better go lie down.
      • Problem is most homes are built wrong. the same damn cookie cutter McMansions that are designed by idiot architects.
        Oh and insulate your home, replace your windows with triple pane and low-e glass, and get rid of all air leaks.

        Problem is, your way of building homes is wrong. If you aim your house south (or north, in the southern hemisphere) and use high-E glass and proper overhangs, you get heat in the winter and cool in the summer. If you live where you never need heat then "proper overhangs" means that they never let the sun shine in directly. Using low-E glass traps heat in the summer.

        There are numerous other things that can be done to improve heating and cooling efficiency, for example cooling towers for ventilation, or simpl

      • 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 [] 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 Spazmania ( 174582 ) on Monday June 21, 2010 @10:46AM (#32640968) Homepage

          can't tolerate it mentally.

          That's about right. I program computers for a living. Deep concentration for long periods of time is a key skill. Above the mid 70's I find it difficult to concentrate.

          Then there's the humidity. The summer humidity around here is routinely 70%. I own a lot of expensive electronics. 70% plus heat is ruinous. Rust and corrosion. Oxidation. I'd lose half the electricity savings to early failure of my electronics.

        • 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 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.

        • Re: (Score:3, Insightful)

          by danlip ( 737336 )

          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 hou

      • Re: (Score:3, Funny)

        by camperdave ( 969942 )
        get a 20 SEER rating AC unit and you will have the most efficient you can get today

        I don't think I could even find 20 seers, let alone get them to agree on which AC I should buy.
      • by kimvette ( 919543 ) on Monday June 21, 2010 @12:19PM (#32642460) Homepage Journal

        In highly sealed buildings they actually need to install air exchangers due to indoor air pollution. Remember: synthetics (carpet, formica, your freezer and rerigerator) outgas, mold grows (I don't care HOW much you clean, if you live in a region where humidity resembles a steam room you WILL get mold), people sneeze, insects and other wild creatures (small rodents, etc.) will find or make a way into your home and they pollute. All mammals, including people, shed. Cooking creates pollutants (oils, soot, etc.) and so forth.

        So, in a modern semi-airtight building you need an air exchanger. Check this out: [] [] []

    • by sycodon ( 149926 ) on Monday June 21, 2010 @09:31AM (#32639926)

      This is a perfect example of how any approach to reducing the carbon should be handled.

      Instead of brow beating everyone into paying more for less and prattling on about the environment and how we are all going to die, just make a device that accomplishes what you want while making it cheaper for the consumer.

      Reduce Carbon, impact "global warming"...sorry, "climate change", pay more = boring, politically charged, scam written all over it.

      Reduce cooling costs 50%-90% = Where can I buy one NOW!?!

      This is what you call a win-win.

    • by Svartalf ( 2997 ) on Monday June 21, 2010 @10:29AM (#32640658) Homepage

      If you're in AZ, NM, or Western TX, you can already get there without waiting.

      Coolerado [] produces high performance indirect evaporative cooling systems for sale. Currently being mainly marketed to the business space, I'm sure you could conceivably get them to sell a 3-6 ton capacity system (as those were designed as residential/business units) to you since they work better overall than the NREL units. The NREL units have one thing over the Coolerado units in that they appear to work fairly well in areas like DFW, Houston, Miami, etc. where the humidity takes a good portion of the ability to cool anything by evaporative cooling. The DFW area is just at the edge of the region that evaporative cooling doesn't buy you nearly enough cooling.

      What I'm wondering is whether one could apply the heat driven desiccant system as a dryer front-end to a Coolerado unit. As it stands, they've got this portable 6-ton capacity cooling system on a trailer with a set of solar panels that demo the efficiency of their systems. They're doing it with only about 600 watts of power with the demo system.

      As for the desiccants, they're just something like Calcium Chloride in a concentrated solution (i.e. brine)- which means you'll have some periodic parts maintenance much like you would with a water treatment system. You might need to occasionally drain off the brine tank for maintenance, but you'll probably be able to simply capture it and put it back in the system. There's really little that can exist within a brine solution, so you won't have bacterial/algal buildup as a concern with that part of the system.

  • by tagno25 ( 1518033 ) on Monday June 21, 2010 @04:42AM (#32638270)

    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.

    or the servers that are being cooled?

    • by somersault ( 912633 ) on Monday June 21, 2010 @04:45AM (#32638284) Homepage Journal

      And how are they going to pipe down solar gas into your server room anyway?

    • Re: (Score:3, Informative)

      or the servers that are being cooled?

      Why not? In the opposite situation to AC, I know the PDC [] supercomputing center in Stockholm, Sweden feeds the surplus heat from their machines into the local district heating system.
      Perhaps even more originally, those crafty Swedes have also hooked up their crematoriums []!

      • by daem0n1x ( 748565 ) on Monday June 21, 2010 @06:06AM (#32638652)

        Oh, those fucking nanny-state latte-drinking faggie euro-trash tree-hugging abortionist lesbian pot-smoking liberals! That be a strike against liberty!

        God gave me the right of freezing to death without having that nanny-state surplus heat fed into my heating system. If I want heat, I'll buy my own oil and heat myself, thank you!

        First, you accept their surplus heat, then you go to the hospital for free, when you least expect it you're all dressed in red, singing "The International".

    • I'm afraid of one thing: if that filter isn't 100% efficient, salt particles everywhere!
      Not harmful to humans (quite healthy actually) but not good for electronics.

    • Yes, if your servers run at some high temperature - I assume above water boiling point, based on the specific type of liquid dessicant. Maybe quite a bit more than the boiling point, as it seems this uses a chemical bond

    • Re: (Score:3, Interesting)

      by Spazmania ( 174582 )

      Such as a 200 degree Fahrenheit heat source. Not servers. And solar only gets you part of the way there. Unless you have a source of high temperature waste heat (e.g. cooking exhaust) or live in a relatively dry climate, you'll spend a lot of money powering the desiccant recycling loop.

  • by OnePumpChump ( 1560417 ) on Monday June 21, 2010 @04:43AM (#32638272)
    Swamp coolers use a LOT of water. Is this better than them in terms of water use? If not, it's just trading one environmental ill for another. The places that have water to spare also have humidity high enough that even this system might not do so well with its evaporative cooling, and the places where evaporative cooling works best don't have the water to spare.
    • by Trepidity ( 597 ) <delirium-slashdot.hackish@org> 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.

      • 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 chrysrobyn ( 106763 ) on Monday June 21, 2010 @09:44AM (#32640088)

          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.

          Wikipedia doesn't do the principle justice. A swamp cooler is essentially a big fiber mesh (which can look and feel similar to cardboard but holds up when it gets wet). This mesh is constantly sprayed with jets of water to keep it wet -- damp isn't enough. A big fan, bigger than a typical air conditioner, forces air through this mesh and pushes it into the house. Each room that needs to be cooled needs to vent air out, typically into the attic and out into the outside. The more air you move through this mesh, the cooler the house, so it's typical that the air volume is much higher than an air conditioner.

          The humid air introduced into the house is essentially at dew point (if it's lower than dew point, the mesh / jets aren't doing their job forcing the water into the air), so the house will likely be warmer than that, making a few assumptions about the conditions outside. Now, if you had this pre-drier in Alabama, dropping the dew point to 40 or 50, you'd be able to cool the air 20 or so degrees -- about what your air conditioner does.

          By the way, I grew up in Phoenix. Instead of the $400/month power bills from running the air conditioners, my parents opted to run swamp coolers. The water bill regularly got above $100/month, but the electric bill didn't. Financially, it was a good trade-off. I'm told there are health benefits from breathing more humid air instead of dry desert air, and the air was constantly being refreshed from the outside, so there certainly weren't any toxic house concerns that people in some areas of the country have. On the flip side, there's the monsoon season, which is typically the whole month of August; the dew point rises to the point where swamp coolers just don't cool much. Several of my Magic: The Gathering cards (mostly Revised aka 3rd Edition) felt like they had a powdery coating on them. I assume this is mold. If it was on my cards, I'm certain it was on countless other surfaces we just never touched enough.

    • Re: (Score:3, Interesting)

      by Phat_Tony ( 661117 ) *
      How much water does it use, and also, if it were rolled out city-wide, how much would it increase local humidity on those hot, still days?
      • by SharpFang ( 651121 ) on Monday June 21, 2010 @05:58AM (#32638606) Homepage Journal

        1) it can use salty water. It's drinking water that we are short on.
        2) cooling the air extracts humidity from it. If the dehumidifier filter is ~99% efficient, it will receive more water from intake air than lose at the filter.

        • Re: (Score:3, Insightful)

          by chrysrobyn ( 106763 )

          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 duc

          • Re: (Score:3, Informative)

            by SharpFang ( 651121 )

            Why do you believe it can use salty water?

            "a very strong aqueous solution of lithium chloride or sodium chloride"

            That's salty water.

  • 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.

    • I keep my house at 78 in the summer, I have ceiling fans in all the rooms I frequently use in the day. Throw in nine foot ceilings and it is very comfortable; especially when compared to the 90+ high humidity days we have in Georgia. Last year my highest bill in the summer was $140. This is four thousand square feet of home. Granted the other electrical costs are pretty low because of CFLs everywhere, a LED based projection tv - we only have one tv, and Macs/Pcs that sleep often.

      That compares to some fr

      • My home stays 70 degrees at 50-55% RH year round. My power bill runs about 150-175 a month. My gas bills runs about 65-75 a month from late Oct to late Feb. Here in the next year or two, I will go ahead and have either a couple of cooling wells drilled or DIY a trench system for a geothermal HP. I am still using a 10 SEER HP and 90% propane converted furnace. But then again, I spent good money and a lot of effort installing insulation when building, and making an optimal duct system, along with using ERVs.
    • Most homes in the US should be able to recuperate an investment in insulation within 4 years. Most stock market traders would bugger their own mother for that kind of a (guaranteed) return.
      • You mean I can break even after only four years? Sign me up!
        • by name_already_taken ( 540581 ) on Monday June 21, 2010 @10:42AM (#32640892)

          You mean I can break even after only four years? Sign me up!

          Generally that's true in older, poorly insulated homes. In more recently constructed homes (10 years old or less) adding additional insulation will have a longer payback period. That is, if the builder actually insulated the home as required. Most screw it up somewhere.

          On the other hand, the 1920s portion of my home was made significantly warmer last winter with about $50 worth of cans of expanding foam sealant.

          The 1990s portion was built with really good insulation, and there's just not much to be gained there. Some, but not much.

          I am considering temporarily pulling some of the attic insulation out so I can seal all the tiny holes in the electrical boxes above things like light fixtures, and seal the boxes to the ceiling board. Supposedly the small amount of airflow leaking from these fixtures adds up to a significant heat loss, and the only expense to fix it is a roll of foil tape used on the backside of the boxes.

          Since I have a gas forced-air furnace for heat, which uses air for combustion, I'm going to install a cold-air intake on the outside of the house with insulated duct all the way to just outside the furnace cabinet. The first year we were in this house I noticed cold air coming into the basement - it was being pulled down the balloon-framed walls all the way from the attic, because the furnace burner creates a low pressure area in the basement. The cold air also had a side effect of cooling the walls as it flowed down to the basement. Cost for the cold air intake should be under $50. I expect it to pay for itself in the first month of winter.

          • Re: (Score:3, Informative)

            by adolf ( 21054 )

            Lots of higher-efficiency furnaces already have a spot to tie an intake plenum into place. My current ancient house uses black 2" ABS pipe for intake and exhaust. My previous ancient house used 2" PVC for exhaust, and had nothing for intake, like yours. It wouldn't have been obvious to me that it was designed to support a dedicated intake line if I hadn't read the book for that particular unit, but the fittings were right there if one knew to look for them. (I never did hook that up, because we were hav

    • They are... when they buy a new house. The problem is far more people buy 20+ year old houses than build new ones. Re-insulating an older house is prohibitively expensive.
      • Re: (Score:3, Interesting)

        by jackbird ( 721605 )
        That depends. If you're even a little bit handy and have an accessible attic, blowing in cellulose ot fiberglass to take it to R38 or better is only a couple hundred dollars and a day of your time, and should pay for itself the first winter. And if you're repainting a room, drilling holes and blowing cellulose into the exterior wall cavities isn't too bad either.
        • Re: (Score:3, Informative)

          by tibit ( 1762298 )

          Even re-insulating the walls is fairly easy once you start doing the whole house, room-by-room. The first room is going to be hard, the second much less so, and the third one will be a non-thinker, almost.

          I have recently faced taking off a horrible straw mat wallpaper. After spending 2 hours cleaning up one 4x7' section, it became obvious that taking down the drywall will be much easier. Especially that I had to run some new wire, and I hate unsupported wires just hanging in there; there is a point when pat

  • The key to TFA (Score:5, Informative)

    by dtmos ( 447842 ) * on Monday June 21, 2010 @05:12AM (#32638392)

    "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."

    Or, maybe,

    Inventing a device simple enough for easy installation and maintenance is what has impaired desiccant cooling from entering into commercial and residential cooling markets.

    As TFA states, desiccant cooling has been known since at least Carrier's work at the turn of the 20th Century. The trick has always been to make a practical desiccant cooling system.

    • > The trick has always been to make a practical desiccant cooling system.

      NREL has patented the DEVap concept, and Kozubal expects that over the next couple of years he will be working on making the device smaller and simpler and perfecting the heat transfer to make DEVap more cost effective.

      which means it still is not practical... or at least practical enough.

  • Dr. John Gorrie (Score:5, Interesting)

    by dtmos ( 447842 ) * on Monday June 21, 2010 @05:29AM (#32638468)

    Few people have heard of the true inventor of both air conditioning and the artificial ice machine, Dr. John Gorrie [], of Apalachicola, Florida, who received the first patent (number 8080 []) for a machine to make ice, on May 6, 1851. While it was reduced to practice (he used it to cool the rooms of his fever patients, and gave iced drinks to his guests at parties -- a fantastic novelty in 1850s Florida) he was unable to make a financial success of the venture. His machine was the first to make use of the refrigeration method of air conditioning.

    • Re: (Score:3, Informative) [] Think this is the guy you are looking for. An ice maker, which didn't work very well does not in any stretch equal air conditioning. And the idea of evaporative cooling, using liquids other than water, was done by a dude using ether dripping through a small hole to produce cooling.
      • Re:Dr. John Gorrie (Score:4, Interesting)

        by dtmos ( 447842 ) * on Monday June 21, 2010 @10:16AM (#32640458)

        If you visit the John Gorrie Museum State Park [] in Apalachicola, Florida, you'll learn more about Gorrie than what is on the web. For example, he employed forced-air distribution of the cooled air by means of vents into multiple rooms, much as central air conditioning systems do today.

        As it happens, while he started work on an air conditioning system to help his fever patients, he moved to ice production as a quicker way to market. At that time, people used ice for cooling when necessary, so there was an existing market and distribution system for it. However, the ice was shipped from the North, and thus very expensive, so there was a ready market for an ice machine making inexpensive ice.* The idea of central air conditioning was a bigger conceptual leap for the times, especially since there was no electrical grid and motive power would have to be supplied by steam engines, which would make the central cooling of buildings very expensive.

        By the time Carrier arrived, in the 20th Century, the economics had changed; the electrical grid, combined with a ready industrial need for refrigeration, made all the difference -- as did his location: Carrier was from New York.
        *He thought; in reality he was "a hick from the sticks," without the funding needed to bring his invention to market, and was never able to complete with the entrenched power of the ice companies of the day -- who, of course, saw the ice machine as a threat to their existing businesses and did all they could to discourage him. Recall that there were no venture capitalists at that time; if you were a struggling inventor you either had the backing of wealthy friends (Gorrie didn't), or you got a government grant to support your work (as Samuel F. B. Morse had done with the telegraph a few years earlier). The building animosity of North vs. South that would soon lead to the Civil War didn't help matters, either; he was a Southerner, while the potential financial backers (and the ice companies) were all in the North.

  • That's all well and good, but I'd rather see efficiency advances in solid state cooling (quieter, more reliable, often smaller...)

  • It must be hard to spell the word "desiccant" correctly, especially after you have just copied the correct name (Desiccant-Enhanced eVaporative air conditioner) from TFA.
  • We are getting a new AC system in our DC in a few weeks and this sounds pretty much exactly like the things they do.

    Can someone enlighten me, please?

  • Is that we'll all have this in 3-5 years!

  • Propane efficiency (Score:4, Interesting)

    by vvaduva ( 859950 ) on Monday June 21, 2010 @08:54AM (#32639546)

    How does it compare with efficiency of propane cooling? For the foreseeable future propane will continue to be created by oil industry, regardless of the idealism of some environmentalists, so it will continue to be used in homes for heating. For cost-saving purposes, propane fridges and freezers are being used quite often in remote areas - they are also extremely efficient. I am curious how the two systems compare in efficiency.

  • Dessicant reaction (Score:3, Interesting)

    by russotto ( 537200 ) on Monday June 21, 2010 @03:02PM (#32644524) Journal

    Calcium chloride is interesting: put a pan of it in a humid room and it dissolves in the water it absorbs. But it also gets hot when it does so, which would seem to defeat the purpose. I wonder how they get around that problem.

System checkpoint complete.