Since the ground, about 6 ft down, stays a consistent temperature of 65° F, why couldn’t a trench be dug in a snake formation where piping about 3-6″ diameter be laid so that outside air can be drawn through the tubing and piped into the house to keep it cool?
The piping would need a drip system to handle the condensation, maybe use drain pipe (with the holes in the bottom).
Thomas Jefferson’s house had a coupula that naturally drew air out the top and pulling air in through the windows. In the above design, rather than windows, the piping system would be used.
Wouldn’t this be more economical that a HVAC system?
Could this work?
What problems would be anticipated?
Replies
It would take so much large pipe to move enough air to do any good at all that it wouldn't be cost effective plus the cost of running large dehumidifers to get the moisture out. There are geothermal AC system that work on the same principle but they are not economical.
Blanket statements about GeoThermal are completely off base. With access to a pond or lake, geothermanl is CHEAP and where ever lot sizes are large and bedrock is deep, ground loops arent that expensive. You get the bonus of free hot water in the summer if you set it up right and your heating bills are low all winter.
Here we go down the rabbit hole!
Even if that were true how many people have access to a private pond or lake? How many people have a lot large enough and without bedrock, 1%, 1/2 of 1%? So, we can throw a local water source out the door. For the rest of us geothermal means a 3' wide, 5' deep and 150' long trench with 750 ' of pipe in it for each ton of AC. Trenches need to be 10' apart. How do you do that on a typical zero lot line lot? There is no magic trench maker and no free pumps. Down here in south Florida a 3 ton geo system starts at $25,000 and gos up rapidly. My brother priced one at his house that was over $60,000.00. Where is it cheap?
I guess I forgot that the only places they build houses is on the coasts...Florida isn’t the center of the universe. Try getting out of your bubble sometime.
Geothermal is certainly done, and is nothing new or revolutionary. As folks have stated, it depends a lot on climate, availability of land, and details about the ground composition and geography.
Wow, like I said, right down the rabbit hole with ad hominems.
Do you have anything constructive to add? You have geothermal at your house? You've installled a bunch of systems? Have you ever priced a system? You're sure that the only experience I have is in Florida, which is not all coast by the way?Do you have any responses to any of my points about geothermal?
I agree w/ Dan.
Re: GSHP (ground source heat pumps) should never be labeled not economical. I've worked with these systems for many years. I've determined that they can be very expensive, but have also used systems that were less expensive than conventional systems. Time an place for everything. Without knowing the site specifics you/we should never make generalizations.
Also there are 4 basic GSHP system types. One uses closed loop wells (vertical bore holes in the industry) that take up very little footprint. All systems require different conditions/requirements for curbing cost.
The OP never mentioned geothermal. His question was about burying large pipes to move air. I threw in a line about geothermal in case he was interested but obviously to someone looking for FREE cooling geothermal is not economical at all.
I'd sure be interested in learning more about the GSHp systems that are less expensive than conventional systems which run about $8,000.00 for a 3-ton system with ducts around here.
There is no reason why moisture would be introduced, if the ducting is tight. If you draw in outside air, that of course would contain moisture, but if you recirculate there would be none added.
You would need some sort of small sump pump (ie, a "condensate pump") to draw condensation out of the duct, since moisture from breathing and cooking and the like will still condense.
So which is it?
"There
So which is it?
"There is no reason why moisture would be introduced"
or
"You would need some sort of small sump pump (ie, a "condensate pump") to draw condensation out of the duct, since moisture from breathing and cooking and the like will still condense"
Condensation is moisture.
Moisture isn't introduced by the cooling, it was there all along. But when the air gets below the dew point it condenses.
If this were a TV show everyone would be looking at you and pounding their heads against the wall while the audience howled with laughter.
We have a daylight basement - and I chose not to insulate the full height concrete walls, as the ground here is a bit over 60 deg. This basically has become our cooling source in the summer. As for the winter, we have a pellet stove to keep it warm - and 60 deg walls are near as bad as the external 40's. Overall I think it's been fantastic over the past 12 years.
So a trench for cool air - seems to make sense to me as long as you can economically push the air through. It's just a heat exchanger, nothing more magical than that. I'd think the cost would be minimal to install - maybe digging the trench would be the main cost issue.
That is an option. But humidity issues have to be considered. Climate will be a factor. Taking in outside air vs return/recirculated air (from the house) are the two basic options. Part will depend on climate. I read an article once on sizing a system.
Taking in outside (ventilation) air would mean taking in e.g. 90+ degF air and cooling it ... which may require a larger 'system' than recirculating air from the house. Accumulation of moisture can be an issue. As stated by others, you may need to consider dehumidification ... but also, any accumulation of moisture can result in e.g. mold/mildew. Lots to think about. if you have access to e.g. a backhoe, that can cut costs a lot ( a big part of the cost). Food for thought.
Ignoring all the inefficiencies of this system such as the thermal conductivity of the pipe and the soil around the pipe, etc., if you cool the air to 65 degrees (your soil temp) and your air is humid enough to condense in the pipe, your output air will have a dew point of 65 degrees. Assuming you are cooling to 78 degrees, your "cool" air will be about 70% humidity when it warms to 78 degrees. Your house will presumably be higher humidity than that with moisture migration from outside and moisture released inside from sweaty people, showers, cooking etc. This will result in uncomfortably humid conditions.
A/c evaporator coils run at about 50 degrees to provide sufficient dehumidification. You won't get this with 65 degree tubes. You will also need at least twice the air flow to provide the necessary cooling at 65 as you get with a conventional a/c unit which will require a very large number of pipes and large ducting to get the needed cooling. If you want to cool to less than 78 degrees, this ratio gets worse.
Your tubing needs to be air tight or it has the potential to be a radon superhighway.