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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/
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.
what if it never cools off at night? it’s been in the 80s at night in southern Illinois. how do you get the humidity out of the house?
jc
You’re looking at a distinctly unusual climate, there, with low humidity and sharp changes in daily temperature. There probably won’t actually even be much mold around, to start with, because there isn’t any place for them to live… err… wasn’t any place for them to live. The slime factor may get interesting presently. In any event, not exactly a practical solution unless you live in a high desert zone.
What makes you think PG&E is going to fund everyone building a big heat sink near their home? Sell to the free market.
Just another tulip in the bouquette: I thought it was a bit Rube Goldberg when I first saw it but my company built another large building and it costed out to use an “off hours chillder plant” where we bought electricity in the early AM hours and made ice cubes. Then during the day when electricity rates went up, we cooled the building by running chilled water everywhere.
Now–thats inefficient until you throw in “market inequities” and so forth. We also would turn on our own emergency generators during high peak times to further our market based incentives.
Follow the money—and it paid for itself in about 10 years. Still going strong now.
As to Perkels design–philosophically more pure using just the physics involved. Seems to me to really be effective the Mass of the storage would have to at least equal the mass of the home if not by 3-4 times more?
That sun is monstrously hot.
It took balls to submit this article. Its just another self promotional attempt to make the blogger-engineer leap. Clearly the gap is much wider than anticipated. Pass the marshmallows & sticks before flame out.
No its not.
Next you know, he’ll want to be a lawyer.
So what if he did want to be a lawyer. What exactly is your point?
Is it the “leap” that gives you the concern, “make the blogger-engineer leap”?
Is it just doing something different then you expect, making a change that gives you concern?
What is it; what is your point?
Does everyone have to abide stickily by your definition of a blogger, what ever that is?
Finally, what is it about you, that any blogger should care you have “issues”?
6 questions. You haven’t a clue, and will likely stay that way.
Thomas Jefferson used the same principle in the design of Monticello. So it is not new. Many years ago I saw a report of a similar unit using buried granite gravel under the house’s driveway. Piping containing refrigerant moved the heat back and forth. The side benefit was that the driveway never had snow in the winter.
Why would you move the cold from the driveway into the house?
I have noticed again that the water coming from my kitchen tap is significantly cooler than the air temp in the house. Now–if there was some way to run the entire water supply of the neighborhood thru a radiator/heat exchanger in my house, I could have free air conditioning and most people wouldn’t even notice the heat gain to their own usage.
I wonder what volume of water over what temperature difference over what length of time it would take to cool my house with city water?
There must be a chart for that available on the web?
Yet another man who invented solar power.
Did you know 99% of American homes are designed incorrectly?
They put the air ducts in the cold zone of the house, resulting in a 25% increase in energy consumption.
The housing industry has gotten lazy, and to keep homes cheap yet still give the homeowner the useless marble countertops they want, they have engineered a home to be absolutely terrible in energy savings.
If a home was simply built to have air ducts in the warm zone of the house (the part you live in), either through cathedralization of the attic or though a double thick ceiling, it would save more energy than all the attick insulation, storm windows and high SEER units put together.
A swamp cooler with concrete blocks. I guess it might work in arid areas.