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I have developed an alternative air conditioning system that works even in the hot summers of Gilroy. I hope to get the attention of PG&E who should love the idea as well as other local inventors.
To summarize how it works, I use 360 concrete blocks to store the coolness of the night air and then blow it into the house in the day time when it gets hot. I’m time shifting the coolness of the night into the daytime.
Additionally I have drip lines in the concrete blocks so I’m using wet concrete. That increases the thermal mass and it provides evaporative cooling which greatly increases the cooling power of the system. The hotter it gets the better it evaporates water. Think of it as a personal cave.
Gilroy California is a small town about 25 miles south of San Jose California. Gilroy is somewhat known for the hot summer days setting records for the area. But at night the temperature usually drops in the range of 55-60 at night. This isn’t something that would work in Georgia, but west of the Rock Mountains it’s ideal.
The system was very inexpensive to build. It uses simple controls – no computers – and it works pretty well. Runs off a standard thermostat, a hose timer, and another timer to run it at night to coll it off from 12 midnight to 6:00 am. Had to use a couple relays to activate the fans and 2 damper valves. it uses about 12 gallons of water a day.
Because it uses just fans and water the electrical draw is far lower than an air conditioner. It also saves power at the hottest part of the day when PG&E really needs people to save power. This system works up to about 105 degrees. If I had used bigger ducting and 500 concrete blocks it would work all the way up to 110 degrees. that’s how hot it got here this summer in Gilroy. It is not August and only hard to use the air conditioner for 3 days this year for 1/2 hour a day.
If this system were incorporated in new construction it would save enough power so that PG&E could build less power plants to take care of peak capacity. Hoping that PG&E is interested in green alternative energy systems that save a lot of electricity.
More Pics: http://ctyme.com/pics/aircond/
Isnt this just a very large heat exchanger? I had a friend who did this by building 2 wells under the house he built. The raidiator would dump the heat into one well, and pick up the cold from the other well. Was very very cheap cold air.
You are just compensating for not using a compressor system by making it megahuge to collect the cold.
Still, I wish you the best, mate. May you become one of the evil terrible, and oppressive rich people that Obama hates so much 🙂
Can the process be reversed to provide heating in winter/fall?
This would certainly make wind power less unreasonable, as it is currently failing when it is needed most.
You really should eliminate the earth to wood contact.
Actually the wood isn’t in contact with the ground.
iM SORRY, but this is To big..
TRY THIS..
6+ plastic barrels 3 feet below the earths surface.
Under foundation is perfect.
Inter connect them with 3/4-1″ pipe/nose..
Have radiators inside the home and a small pump to push the water.
Fans on each radiator Exchange heat, which is then PUMPED back into the Barrels..
This will work, Summer and Winter.
the barrels will keep about 50-60 degrees of temp from the Earth insulation.
If nothing else, I wouild replace all that Concrete, with GLASS POP/BEER bottles..
Good idea and great it works for you. be careful with the water though, or any moisture for that matter. All those cavities that make this work are great breading grounds for some mold you may not want. A mild chlorine solution once and a while could control it, but careful monitoring is needed. There are other ways to do this listed on some energy conservation sites.
-way to go Marc
simplicity at it’s best! -i love it 🙂
smart move keeping computers out of the mix.
-s
Very neat construction there–my compliments.
This is not a heat exchanger by standard definitions. Rather a heat/(cold) thermal mass storage system which is well understood. Did you review the storage mediums available for the pro’s and con’s?===what made you choose cinder block over loose gravel or water or solid brick thermal mass wall?
The draw back is “usually” not enough heat differential to do two things: 1–provide enough of a temp difference to feel like you are really getting the cooling, and 2–usually not enough total heat/cool reserve to work the full long day needed.
Once you start dripping water on the thing, why not use a swamp cooler? Smaller, cheaper, easier maintenance, moveable. I’d be afraid of mold growing on the cinder blocks.
Lots of “things” work great when first built. over time, they don’t stand up to the wear and tear, maintenance required.
I do hope you keep us informed as you go along. Congrats!
The interesting thing about swamp coolers is that they don’t work in a swamp.
Ha, ha….. well, you’ve still got the fan?
Dude?…Dude!
That is one HUGE bong, man! Keep cool while keeping crunchy.
Water has the higher specific heat than anything else, it’s cheaper than concrete blocks, and if it gets a few germs in it, what’s the worry as long as it’s sealed?
I’m going to guess that the specific heat of water [1] multiplied by the density of water [1] is higher than the specific heat of cinder blocks multiplied by the density of cinder blocks [=1]. This means that using water as your thermal mass is more efficient as a thermal mass. Some investigation in the past has shown me that there is no common substance with a higher result when you multiply these two numbers. I’d be interested in Marc’s thoughts on this.
clarification:
specific heat of water * density of water = 1
specific heat of cinder blocks * density of cinder blocks < 1
He isn’t really using cinder blocks as a thermal mass – most of the cooling power is from the evaporation of the water. This is just a swamp cooler.
Think of putting a wet towel over a fan – the cinder blocks are just the towel
We’d have to run the numbers for that. I’m thinking the cinder blocks benefit is providing more surface area for the heat transfer which makes the storage capacity greatly reduced.
All these conflicting/off setting issues.
With nothing but gut feel, I’d be surprised what I see pictured would cool off very much at all from the thermal mass perspective. Whole lot of surface area there as said would make the swamp cooler aspect work real well. To the degree that is true==seems like a standard swamp cooler would be much preferred.
Take two days in a row of equal temps and run the system with water drip one day then no water drip the next. Compare. Then marvel at the work of using brick instead of matted straw.
This is well understood, documented, charted, measured technology.
Is Legionaries Disease a kind of mold?
Marc,
What ever happened to you pet squirrel?
Great job Marc. Maybe you can qualify for Friends of Obomba renewable energy money and then file for bankruptcy.
What about the squirrel?
What the hell is up with the idiot spammers posting in the blog……….
Great concept, but will not work in many areas (particularly the southeast) where night temperatures do not fall much.
A high of 98 with a low of 89 for 4 months of the year would not allow this concept to replace current A/Cs.
This is perfect for desert and dry Mediterranean like climates.
If it works for you good show. There are a lot of ways to pull this off.
A man I knew used water from a creek to cool his home.
I actually had fair luck just running fans at night and then blocking the rooms with the fans during the day time. I had to be careful about not running heat sources during the day but the house was much cooler than it would have otherwise been.
You can sort of pull the same stunt by running your air conditioning on extra cool after 12:00 at night and the turning it up to 80 or so during the day.
Ok, than main problem you have hear is De-humidification. Not getting cold enough to remove water from the air.
In Texas, there is no coolness of night. 84 degrees is not cool.
My energy-efficient home utilizes super-efficient spray foam insulation coupled with a super-efficient Mitsubishi mini-split A/C with a SEER rating of 24.
Super-insulating a home during the construction phase here in Texas returns more dollars than other methods when coupled with super-efficient A/C. The water heater is also super-insulated and on a timer that keeps it turned off 16 hours of the day.
Sounds just super!
I changed majors from engineering to computer science before I had to take thermogoddamics, but if you were to go commercial you would probably want to have some kind of analysis done.
When you use enthalpic heat for transfer, you (can) gain a lot of efficiency. (Enthalpic heat is the gain or loss of heat when a substance changes from solid to liquid (ice-water) and vice versa.) It’s actually a little like compressing a file before you move it. You use a certain amount of resources compressing the file, and a certain amount moving it. As Andy Tannenbaum said “Never underestimate the bandwidth of a station wagon hurtling down the interstate at 80 mph.” (That’s relevant but I’m too lazy to explain it.)
gwaddamit. Supposed to read “Never underestimate the bandwidth of a station wagon FULL OF 9 TRACK TAPES hurtling down the interstate at 80 mph.”
Maybe it’s not relevant but I use that quote whenever I can.
One thing to keep in mind is that concrete isn’t the best thermal mass storage, and it’s not the best evaporator, and it’s not the best heat exchanger, but it does all 3 and it’s cheap and simple. When you look at it that way it makes more sense.
I like it and congrats! Underground is cool and ideally under the house to keep the floor cool. Also adjacent to the underground meat locker.
geothermal on the cheap…..
Kind of a combination heat-exchanger/swamp cooler. I live in humid Missouri, where last july I count 11 days in 3 digits, 11 more 95-99 with only 1 day where the high only hit the upper 80s. We need moisture removed from the air in summer time so it wouldn’t work for here. We also have lots of caves here, but would be careful using the real thing too, as there are gasses in deep earth you don’t really want to breath all the time.
Good project, nice work, but wouldn’t work for a moist climate. Thanks for the post tho..
So how can you control humidity on the cheap?
Zero Energy Design is a web site that discusses various design concepts for controlling heat and humidity in a state like Florida.
Many so-called “energy experts” have incorrectly stated: “Passive solar systems do NOT work in hot humid climates like Florida.” This statement is partially correct IF you constrain your simplistic thinking to conventional single-shell houses, but this ignorance is quite false IF you understand the powerful science documented by Zero Energy Design®.
There are solar powered de-humidifiers==desiccant fills with water from the house then rotates to solar heater to have the moisture evaporated out. Rinse and repeat.
Like most “solutions” it works best within very restricted parameters. But so very nice when it does work?
For most homes situations, I find a cheap window a/c unit running more to remove the moisture than to cool is very cost effective. YMMV.
I “love” the whole concept of Super Insulation. It makes so much sense. Figures its hardly used in the USA.
http://youtube.com/watch?v=bSZH0K-Qhuw
Darkness and water = Mold issues.
I agree mold would obviously be a concern, but… Couldn’t a HEPA filter be placed inline to help keep the mold spores from being blown into the house?
Nothing new. See “solar closet”. Using water containers instead of cinder blocks works better.
Or pump-back storage, which power companies with hydro plant have been using for decades.
I see “Hillbilly smartz” has already caught the issue. The night air must be drawn into the system (along with moisture and mold spores) with one set of fans. When morning comes they shut down and the external doors are closed.
The in-house system draws that cool, moist air up into the house during the daytime and, it is assumed, replaces it with the hot,dry air from inside the residence. As evening approaches, the below-house reseviour is so full of hot air that not much cooling can be offered.
In the next iteration, create a closed ducting system for the indoor side. Heat will be exchanged through the wall of the ducts while eliminating the mold and moisture problem.
So in the winter can you run it backward and heat your house at night from the heat stored in the blocks during the day?
No – it’s cooling only.
tHE air PIPE METHOD can..
The water method can..
they are placed under ground. 3-4 feet and can work year round..
You can add another feature with the AIR PIPE method, Where you exchange it from UP STAIRS(high point for COLD AIR, to cool from the TOP DOWN) and then WARM(in winter, across the floors) It will keep a Temp ranging 50-60f year round.
It beats trying to Change TEMPS from Freezing UP TO 70..or Cooling 100 down to 70.
http://www.gogeothermal.co.uk/pdf/GoGeothermal%20AWADUKT%20Thermo%20Sales%20brochure.pdf
AIR VENTING..
I have not seen a cost analysis or Btu analysis, but it seems to me that PG&E would be interested to know those factors.
With new construction, super-insulation and passive solar building design is most effective in reducing peak energy requirements in terms of dollars invested versus return of investment.
As a retrofit, the high-efficiency ductless A/C units with rotary DC compressors draw much less power during peak usage periods.
LG designed a ductless A/C one-ton unit with a 28 SEER rating.
There are multi-zone ductless A/C units that run on 120V and are roughly twice as efficient as central air units.
Typical energy savings are 35% – 50% versus central air with ducting.
In other words, if every household that needs to replace their central air unit would go with a multi-zone mini-split A/C solution, the energy savings would be very substantial and peak power usage would be greatly reduced.
Hmm, ignoring medium and large houses, don’t you need a bunch of those units to fully cover even a minimal 3000 sq. ft. house?
I cool a 1500 sq. ft. house with one 2-ton mini-split A/C, but the house is super-insulated with closed-cell spray foam insulation.
The house is also a two-story. The blower unit is located in the stairwell.
A 3,000 sq. ft. house with spray foam insulation can be cooled with two 2-ton mini-split A/C units at more than twice the energy efficiency of a conventional central air unit.
THere is something you may not see here..
EFFICIENCY SUCKS.
All it means is the corps make less money and CAN SHOW IT, and make you pay MORE.
“fully cover even a minimal 3000 sq. ft. house”. So 3000 sq feet is now considered a small house?
Not every design will work everywhere. I once lived in the mid west where the average humidity is very low. So the air is generally dry, year round. A cheap form of air conditioning called a “Swamp Cooler” worked by drawing air thru a water dampened filter. The evaporation rate dropped the air temp quite well. So no compressor or freon was needed. Just a large squirrel cage fan and motor. The same system would never work in places where the average humidity was in the 70s or higher. This temperature shifting design depends on the nights being far cooler than the days. Which again, mostly happens in very dry and arid places. That don’t retain the heat of the sun, well into the night. Even solar energy has its limits. Above a certain latitude, it’s economically unsound. The panels just don’t get enough sunlight exposure to make them practical. But people still try, cause they don’t understand this. And buy into a lot of salesman hype (aka lies) about their “new and improved” solar panel design, not needing as much sunlight.
An alternative to cooling bricks, for the moister locations, would be to using ground water to cool the air. Since the average temp of water below ground is about 55 degrees F. It would require pumping a closed loop of some fluid/coolant, down into a well, and back up, to essentially “sink” the heat from air, into the ground. Otherwise, just pumping the ground water up, to cool the air, would waste the water, if it wasn’t returned.
Of course, such systems are initially expensive. Due to the well drilling cost. Maybe if one already had a well, they could double purpose it. But the “tap” water extracted would be warmish, in the summer. And very cold in the winter. Because such a heat pump system could also extract some of that stable ground warmth for heating. Anyway, I’ve heard of these, put I don’t personally know of anyone who’s tried one. More likely they’d fall for the hyped promises of Solar.
Evaporative water tower cooling systems that are used to cool large apartment buildings with chilled water can be scaled down to cool a single-family home without the need for a water well. City water can be used and recirculated.
I can see a day where photo-voltaic solar panels with better design efficiencies can be used to power the more efficient rotary DC refrigerant compressors in ductless A/C units.
I don’t currently see a return on investment with a totally solar-powered mini-split A/C, but the day is certainly getting closer.
what part of the “midwest” did you live in where the humidity was very low? or did you “mid west” as “out west”? I assure you swamp coolers won’t work in Illinois.
jc
If it saves energy PG&E will have no interest. Sad but true IMHO.
Actually, they would be if it keeps them from having to build more power plants or upgrade the power grid. They can just charge more for what they already produce.
Cool concept. What about contamination issues? Molds and such? Cleaning? Foundation support?
Mark,
Hats off to doing and understanding a concept that most people dont think about. Thermal mass is a wonderful thing. I design large commercial buildings and we do the same thing. Wait until outside air temp is cool, we also monitor moisture content, and then run fans on low speed to flood the building with cold/dry air and purge warm air out. Schools are generally full of masonry walls and lots of concrete/terrazzo floors that stay cold for a while as the day heats up and we let the building ride farther into the day before needing chiller plants to max out. We pull forecast data to decide if we let the building coast in the afternoon knowing that we can get free cooling late that night to recover it. Nice project, just be careful about the mold that others have mentioned. You might like the idea of an “earth tube”. Just search for “rehau awadukt”, it’s a german based product that is a PVC pipe buried in the ground with a fan. Ground temps at 55 deg F can pre-cool outside air all day and night.