ATS Science Challange: Air Condition a House in high humidity without standard AC/Refrigeration

I'd like to issue a challenge to the ATS community to come up with a way to a Air Condition a House (or large room) in high humidity without standard AC/Refrigeration.

Swamp coolers ( Evaperative Air Coolers) work by using water as a refrigerant. Water is pumped through tubing that is connected to wet pads. A fan picks up dry warm air from outside and blows this air through the wet pads which cools the air and deposits this air into the house. Moisture (humidity) is blown into the house with this air. If the air outside is already too humid, the swamp cooler cannot work, there will not be enough of a temperature to relative humidity difference for a heat transfer to take place.

Modern Air Conditioners are really super efficient air dehydrators. Air conditioners do not " put cold air into a house". Like your refrigerator/ freezer, air conditioners condition the air by removing heat that is stored in water/humidity leaving you with what is left over - air that is now cool or cold. These rely on the presence of humidity inside the house which has warm air to operate.

I'm trying to find a way to air condition my house without the use of standard air conditioning system because I will be running on Solar/Wind/Hydroelectric with battery backup - I don't want to waste my precious Earth resource energy to power such a large device. If anyone can think of a way to do this, the ATS community can.

The U.S. Government's National Renewable Energy Laboratory (NREL) in Golden, CO, ( a division of the Department of Energy) is working on such a device but it's not ready yet and they cannot even be reached at their e-mail. Projected time to ready the project to consumers from 2010 is 5 years. ( 2.5 years ago) I need something now. Here is what they are doing:

"The technology we have today is nearly a hundred years old," says Eric Kozubal, a senior engineer at NREL. Kozubal and colleagues have come up with an air conditioner that combines evaporative cooling with a water-absorbing material to provide cool, dry air while using up to 90 percent less energy. The desiccant-enhanced evaporative, or DEVap, air conditioner is meant to addresses the old complaint, "It's not the heat; it's the humidity," more efficiently.

Evaporative cooling--blowing air across a wet surface to promote evaporation--has long been used in so-called swamp coolers. A method called indirect evaporative cooling improves on this design, dividing air into two streams, which separated by a polymer membrane. Water is passed through one airstream, making it cooler and wetter; the cool air cools the membrane, which in turn cools the air on the other side without adding water.

But air can only hold so much water vapor, so in humid climates the effect is limited. On a 32 ºC day in Houston, Kozubal says, evaporative cooling may only bring the temperature down to about 27 ºC. Ideally, to provide a comfortable building, an air conditioner should cool air to 13 or 16 ºC.

NREL overcomes the humidity problem by adding another step, the use of a material known as a desiccant that absorbs moisture. NREL uses a liquid desiccant, a syrupy solution of lithium chloride or calcium chloride, about 44 percent salt by volume. In this setup, another membrane separates the desiccant from air traveling through a channel. The polymer membrane has pores about 1 micrometer to 3 micrometers in diameter, big enough that water vapor passes through easily while the salty liquid stays put. The membrane is also coated with a Teflon-like substance to repel liquid water. The desiccant pulls moisture from the airstream, leaving dry, warm air. Then it's back to indirect evaporative cooling: in a second channel, water evaporates to cool a secondary airstream, which in turn cools the first airstream, and out comes cool, dry air.

www.technologyreview.com... and another write up about this from June of 2012 www.businessinsider.com... ( I'd try this awesome technology if we had it now, of course the HVAC industry might lobby to squash these advances and we may never see it)

Perhaps the above will give you guys some clues on how to solve my problem.

There is also Thermoelectric cooling but it's not used on the scale of cooling a home or large room. en.wikipedia.org... This technology is used in things like water coolers.

Well ATS, I'll leave you, some of the brightest minds on the planet to have a go at it. You could help change the world and would have my everlasting gratitude.

Shading is key, surrounding your house with plants like trees will help a lot, so will blocking windows. There are a bunch of things you should install into your home. Here's a list of some things I think would help

Trees, Vines and things that provide shade
Thermal Chimney
Roof vent
Ridge Vent

and finally this

www.energybulletin.net/stories/2006-11-22/passive-cooling

Dessicants.

Some commonly used desiccants are: silica gel, activated charcoal, calcium sulfate, calcium chloride, montmorillonite clay, and molecular sieves.

en.wikipedia.org...

The uncomfortable feeling one gets in high temp, high humidity environments is the inability of air movement to "wick away" sweat, creating cooling.

Create a dry environment using dessicants and simple fans may help.

My two cents.

Can't help you with the a/c aspect, but through research this summer I have found a few tips.

1. Position of house - try to position it to get max sun in winter but less in the summer.

2. Plant shady leaf dropping trees as close as possible to your home. Shade in the summer, leafs drop and let sun in during winter.

3. Point fan outwards of the hotter side of the house and open the windows on the cooler side to draw cool air in and blow out heated air.

4. Insulation. Important part of this. Whether it be a house with dirt pushed around the sides or a well insulated attic.

Honestly, my grandmother has a mostly "green" home. She has dirt mounds on three sides, plenty of cross breeze, and shade trees galore. She has one window unit that she never uses. It can be done.

Good luck, I look forward to seeing what the geniuses here come up with because as of right now, my a/c needs replaced and I don't have the $8,000 to spend on it.

reply to post by JohnPhoenix


Coming from the south I can tell you that the best method I as well as my family use is just water your lawn in the morning and nite by your home especially around the home itself if u have one if not swamp cooler but like u said it can only do so much. Thirdly I would suggest wetting a towel/ hancarchief in cold water and tying it around your wrists and neck, since these areas are the ones that emit the most heat. Just my 2pennies hope you find what u are looking for.

you could always have the AC on its own circuit so when the solar powers good the AC will get powered perhaps using panels on somewhere external to the house like a garage in a nice open spot or even as a very cheap option get the Mrs to waft you 24x7 but also look at the natural way the wind blows as perhaps chopping down a few trees/shrubs etc may just allow the breeze to get to your house

I'll say up front, the example I bring, I don't know anything about as a company. Never heard of them,...but I know about the process their diagram shows.



It's NOT cheap and that's why I can't tell you how well it works. I looked very hard at this 2 years ago when I got an inheritance and a desire to look long term sustainability for my own home. This...didn't work for me. Largely because of cost\, honestly. It's not because all the material I researched didn't sound very promising. Ever been in a Cavern? Nice comfy temp....year around, no matter where on Earth you find that cavern to stand in. It's playing on that same theory.

Geothermal Answers

reply to post by JohnPhoenix


This is kinda counter intuitive - Steam can be use to cool. If you have some way to generate steam you could use this method:

Steam Jet Cooling - Wiki

I just saw your other thread Off the Grid heating and cooking for cheap/free so you have more Power left over. Could you use one or a combination of solar sources to generate steam for the Steam Jet Cooling?

reply to post by Wrabbit2000


looking at that picture you need a deep enough hole and a fan to pull the air through the cooler ground

Er.. The Mrs is the problem. I worked for 20 years in the AC and Heating repair business. Hot summers in the backyard working on or installing condensing units, attics in the summer that were over 140 degrees to install the tubing, duct work, evaporator coils and heating/blower systems. I can take the heat and humidity, she can't.

Yes, there are some great tips for sealing your home and making it less prone to heat and humidity : www.hometips.com...

Become a fan of fans, Cut back the transfer of heat through the roof and walls. Weatherize your home to reduce the loss of conditioned air, Install a foil radiant barrier in the attic. Let hot air out of your attic ,Install inexpensive heat-reflecting film on windows that face the sun, Install skylights.,Reduce heat gain by pulling drapes or shades, Turn on the sprinklers., Plant now to provide shade in the future, Closely monitor the temperature both inside and out, Reduce indoor humidity, which makes room air feel warmer, Turn off heat-generating lights and appliances

- more details for each one at the link.

Problem is, I don't have the property yet, and don't know if I will build this house myself or buy an existing home to convert to off the grid living. I may not have control over some of these ideas. It depends on what I find when I start looking for my new place. I'd like to have a more solid solution instead of just relying on such tips. Of course I will implement as many of these as I can, but this will be south Louisiana - swamp territory.

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Wrabbit2000, I like the Geothermal Cooling idea. I'll do more research on it.

Level Headed, I also like the steam jet cooling idea and will do more research on it. - Thanks guys.

Originally posted by Maxatoria
reply to post by Wrabbit2000

 

looking at that picture you need a deep enough hole and a fan to pull the air through the cooler ground

Yup.... Hence...It's expensive and not an option at all depending on where one lives. I can just imagine someone in Los Angeles, for example, going to city planning and explaining how they'd like a permit on their 1/4 acre little residential lot to drill a system like this. They wouldn't have to turn it down...the laughter rattling windows would make it a moot point.

Then again..if one chose the property with this in mind? Well a state like Missouri or Kentucky are both known far and wide for caves and caverns. 6,000 or them in Missouri alone, among just the discovered and officially cataloged. Every so often, news here has a human interest story about folks who made use of the cavern space on their own land in creative ways...like this.

reply to post by JohnPhoenix


I installed a very small garden sprinkler system to my roof 2 years ago. It uses 1/4 inch supply line (4 of them), and very small nozzles. I use a 50 psi regulator and a junction block at the water spigot. The spigot comes from my lawn pump, and it is on a timer to run 20 minutes twice per day. The sprinkler heads cover my entire roof in a very fine mist of water, and it takes 5-10 minutes to coat the roof thoroughly enough for the water to begin running down the roof and into the gutters. This continues for another 10 minutes until the water coming off the roof is warm, but not scalding hot like it is when the first drips form. My timer is set to run early afternoon, and again just before sundown.

My electric bill dropped about $500 the first summer it was hooked up, and another $400 this year after a few minor tweaks to my system.

My logic goes like this. My asphalt roof, and brick exterior absorb heat all day long, and then when the sun sets at night, they continue sending that heat to my house, and so my air conditioner runs a lot more at night than it needs to after the outside air temperature has fallen. In the morning, it takes all morning and some of the afternoon before the roof and bricks are fully heated. If I can dissipate that heat quickly and cheaply, then it takes all afternoon and evening for them to build the heat up all over again. Then, if I can dissipate that heat quickly and cheaply again, they won't reheat overnight, and my air conditioner can run less often.

I'm like you, I plan to be on full-solar power and off-grid very soon. First, I had to cut my energy consumption so instead of requiring a 24 kW system, I can get by on a 12-15kW system. I'm almost there! My next project is to get rid of all my conventional lighting, and switch to recessed and hidden LED lights all around my rooms. It makes a very cool effect, and it uses almost no electricity. For the record, I run 2 Refrigerators, a Pool Pump, a 2500 sq. ft. house, a Well Pump, a Lawn Pump, and lights and outlets for 3 outbuildings, and I have cut over 35% off my consumption in 3 years.

Just found this video with a better explanation of Steam Jet Cooling. Cost they say is just under $20,000. Don't know if I can afford that but this is interesting as hell. Can take the temp down below freezing.

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darkhorserider, Thanks for the info. Pretty cool what you're doing there.

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I found these two cool websites for cheap DIY Geothermal Cooling

www.waldeneffect.org...
mb-soft.com...

If I were going to go with Geothermal Cooling, I'd go with these sites. This guy designed and perfected a cheap DIY Geothermal Cooling system and gave the plans to the world for free.

I heard caves stay cool in summer and warm in winter...so that means if you insulate your home really well...it should stay at a moderate and medium constant temperature all year long, with very little heating or cooling required..

reply to post by JohnPhoenix


I think we'd ALLL want this, expecially if it was super efficient. I can't wait to see some new ideas. I live in super high summer humidity so maybe there are wome other options besides a $400.00 a month AC bill. Of course, we'll all be killed as soon as we are privy to the info. But one cool day in the midst of a 105F 80% humidity day would be worth it! Heating and/or cooling systems are the energy eaters in our society.

reply to post by Gridrebel



It's the cooling I'm worried about. I'm confident enough with the Green DIY heater technology I've talked about in my other threads that heating will be no problem.

I did find this AC unit that was designed for solar where no power grid is available. I have e-mailed the inventor to see how much one of these cost. www.youtube.com...

*** People - Please Flag this thread.

I don't care if you star me or not, but there is so much great info coming form you guys others can benefit from, I think this topic should be Hot and Heavy and give all of ATS a chance to share in the knowledge.

reply to post by JohnPhoenix

You know, I hadn't starred at first. Nothing negative...I'm just not giving as automatically as I once did.. However, reading your plea, you have my flag.

I can see by your mini- you've been here too long to care THAT much about the numbers and I agree, the information on this is very valuable to see become common knowledge. I hope more do add here so it gets wider view.

Wrap your home in aluminum to reflect the sun's rays like me, that's how I foiled the power company.

reply to post by JohnPhoenix


For heat (and it is a good logic for cooling also), I try to conserve heat by only heating the key areas of use. We have propane for heat, and my goal was originally to use less than my normal 2 tanks of propane per year, but I've gone way beyond that now, and I can get by with less than a single tank per year! I use our fireplace in the main living area, and I've taken out the big blower and instead installed two small Radio Shack computer fans and the natural convection of the rising heat. Those little fans make zero noise and use very little electric. (I had to get a transformer to step down the 120 VAC.) It doesn't push out as much volume, but I just shut all the doors and heat the main area we are using. If it gets too hot, I turn on the Central A/C fan to circulate the warm air from that room to all the other rooms.

At night, when we go to bed, I have a small space heater in my room, and the kids room. I dampen the fireplace as much as possible to let it create some heat all night, and I turn our Central Heat thermostat to about 62-65.

In the morning, the bedrooms are warm, but the living area and kitchen have fallen to whatever the thermostat was set at, but its simple enough to turn it up to run the heater for an hour while we all get ready for school and work. We turn it back down to 60 for the daytime, the heater doesn't need to run, and then I build a fire when I get home again.

The wood here is fairly expensive, so this would not be economical if I were buying wood, but I have an old truck, and you can get a $5 permit to cut wood in the National Forest, and I enjoy splitting wood for exercise. So, I cut a truckload 3 or 4 times per year, costs less than $20, gets me and the kids out into the forest, and I save about $400 on propane compared to 3 years ago.

NOTE:
I still have an electric hot water heater. If I had a gas "on demand" type of hot water heater, it would require more propane, but theoretically it should be more cost effective compared to the electric, and it would probably drop my electric consumption down to my goal. My water heater is so new, that I hate to replace it. Instead, I've turned the thermostat on it about as low as it will go. I can stand to wash my hands or dishes under the full hot water without having to turn on the cold. This saves me heating the water up more than it needs, so I might just leave it at that. I don't use any gas during the summer whatsoever, I really only use propane during December and January.

I plan to also run a propane line to my grill, or make a DIY refill for my smaller tanks off my big tank, so I can refill my own grill tanks. Having hot water, and a way to cook during power outtages is a pretty nice amenity, but once I'm on full solar, that will be less important.

You can cool a home with dry ice but there are certain precautions you have to take....


How to use Dry Ice to Cool a House