Forgot your password?
typodupeerror
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."
This discussion has been archived. No new comments can be posted.

New Air Conditioner Process Cuts Energy Use 50-90%

Comments Filter:
  • 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?

  • 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 [wikipedia.org], of Apalachicola, Florida, who received the first patent (number 8080 [uspto.gov]) 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.

  • by Phat_Tony (661117) * on Monday June 21, 2010 @05:48AM (#32638562)
    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.

  • by Anonymous Coward on Monday June 21, 2010 @07:38AM (#32639032)

    You need to do more research. You can put R-400 in the walls and it won't help, because you are dealing with a building that has windows and occupants.

    In most places, solar heat gain is a major component that A/C has to deal with. Humidity in the makeup air is also a large problem for A/C to handle.

    Humans inject heat and water vapor into the building through cooking, respiration, appliances, and opening doors.

    Humans also need fresh air, and you can't -- legally or practically -- build an air-tight building without makeup air.... which introduces more humidity and heat into the building envelope.

    I built my house 2 years ago and used all closed-cell spray foam (isocyanate) making all walls, floor, and roof, water-tight and air-tight. 133 mm of foam gives me R-37 in the walls, and more gives me R-60 in the floor and ceiling. All ducting is in conditioned space. All external walls have thermal breaks (offset studs). I have an ultra-efficient water-jacketed earth-coupled geothermal heat pump. The solar gain in the summer still rapes my house with heat gain. The makeup air I have to have because the house is so damn air-tight, uses a high capacity heat exchanger, but still is a water-vapor sieve pumping water vapor into the conditioned space that the A/C has to then remove.

    So do a little more research before you spout off with drivel.

  • by jackbird (721605) on Monday June 21, 2010 @08:35AM (#32639364)
    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.
  • 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.

  • 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.

  • 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 [floridastateparks.org] 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.

  • by anomaly65 (765909) on Monday June 21, 2010 @10:26AM (#32640604)

    I use a combo of propane(phase change coolant), butane(lowers pressure), and isobutane(carries oil through system) in my home central air (standard compressor/condensor & evaporator type found in US homes). It's roughly 25% more efficient overall than the toxic HCFC's (R22/R410a) due to much lower head pressure. Environmentalists should love it as propane has about 99% less GWP in the case of a system leak. and no patents to bother with!

    If you're thinking of the very old style absorption coolers (boiler, condenser, evaporator and absorber), which requires continuous burning of propane, that method isn't very efficient by comparison. The primary usefulness as you mention is typically due to a lack of electricity in remote areas. absorption chillers cost more to operate than electric chillers. They also cost about twice as much to purchase. Back in the 1920's/1930's ammonia was used in these systems, and leaks were quite toxic to the residents.

    If you have an industrial "waste heat" source, absorption coolers may be useful (no need to burn additional fuel).

  • 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 [coolerado.com] 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 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.

  • 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 sheepofblue (1106227) on Monday June 21, 2010 @10:47AM (#32641000)

    This is another typical over statement. They calculated the efficiency without including the energy that is required to reverse the desiccant used thus the calculation is misleading at best and really just a lie. This seems to be a trend that started with "zero emissions" cars that had the electricity magically appear.

    Believe it when you see calculations based on a closed loop system as I am betting that the efficiency advantage will tumble a LONG way.

  • by Spazmania (174582) on Monday June 21, 2010 @10:53AM (#32641086) Homepage

    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 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:

    http://www.epa.gov/iaq/ia-intro.html [epa.gov]
    http://www.epa.gov/iaq/is-imprv.html [epa.gov]
    http://en.wikipedia.org/wiki/Air_exchanger [wikipedia.org]

  • by Malc (1751) on Monday June 21, 2010 @01:38PM (#32643470)

    When the outside humidity is in the region of 10%, how high does the evaporative cooling raise it? Why is that a problem compared with other places where relative humidity could be in the range of 75-100%? I lived in Shanghai the May-Oct before I lived in Melbourne, and I'd say 30C there was worse than 45C downunder (I might react differently than my computer mind you, which certainly doesn't soak it's case through with sweat).

    I was somewhere near this weather station [berwickweather.info] last year, it reported something like 46.4 on the day of the bush fires. As you can see, both Jan and Feb had days that reached 46. The only cooling we had were fans (I was working from home). Again, I'll take that over Shanghai at a lower temperature. It was quite an incredible experience, with everything in the house seemingly above body temperature (one couldn't even lay down to escape the heat as the bed was hot).

  • 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.

  • by bill_mcgonigle (4333) * on Monday June 21, 2010 @07:48PM (#32647618) Homepage Journal

    Exactly. The real architects are busy designing skyscrapers and expensive custom homes, not shitty subdivisions full of tract homes.

    I think you have the AIA to blame for that. I recently worked on a $3M building project for a nonprofit and the architects routinely wanted 20% of the total cost for their design work, even a two-man shop, and weren't willing to negotiate. They chose to blame AIA rules for their fee. We chose to not work with a design architect and hired a (rare) structural architect for a very high hourly rate to verify the work the engineer and designer did (both on hourly rates themselves). The only reason we chose to hire an architect at all is that the government mandated it (no changes were required). Sweet work when a coercive monopoly mandates your rates. The AMA seems to work similarly.

    Given fixed percentages, the savvy architect will naturally want the most expensive jobs.

    I didn't start this comment intending to implicate government in our energy efficiency woes, but there it is.

Whoever dies with the most toys wins.

Working...