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You can do the same thing today simply by burying tubes in the ground, at least 6 feet down. The ground is cooler in the summer than the air, and warmer in the
by skookumchuck 8y ago
You can do the same thing today simply by burying tubes in the ground, at least 6 feet down. The ground is cooler in the summer than the air, and warmer in the winter. This can pre-heat and pre-cool air for your HVAC system.
It's been around a long time, I'm surprised almost nobody uses it.
- masonic 8y agoNo risk from radon gas?
- skookumchuck 8y agoNo, the tubes exchange heat with the soil, not air. If mildew is a problem, you can run coolant instead through the tubes, with a heat exchanger in the building.
- MertsA 8y agoThere would be an increase in the amount of Radon pulled out of the ground. Usually the way an HVAC system is set up is that you have the filter, then the evaporator coils, then the fan, then the ducts to the rest of the building. To heat or cool the air the tubes would need to be placed before the evaporator coils or it would just be wasting energy instead of saving energy. This also puts it before the fan. Everything before the fan is at a negative relative pressure and everything after it is positively pressurized. Presumably those tubes aren't perfectly sealed so the negative pressure will draw in a tiny bit of Radon from the ground. You could flip things around and move the fan to right after the filter and before the tubes and evaporator coils, I'm not 100% sure why that isn't normally done but all of the residential HVAC units I'm familiar with are done this way so there's probably a reason.
- stjohnswarts 8y agoI can't personally because 8 inches down is solid rock. To remove all that rock would cost a fortune to get down to 6feet.
- chrisbrandow 8y agoDo you use it?
- skookumchuck 8y agoNo and I strongly regret not doing it when the house was built. It could have been done then at minimal cost.
- beerlord 8y agohttps://en.wikipedia.org/wiki/Heat_pump https://en.wikipedia.org/wiki/Heat_pump Do you mean that?
- skookumchuck 8y agohttps://en.wikipedia.org/wiki/Geothermal_heat_pump https://en.wikipedia.org/wiki/Geothermal_heat_pump
- SketchySeaBeast 8y agoIn the north the frost line can get to below seven feet, and even past that you're now pulling cold air in, instead of recirculating already heated air from the house. I think this would work well in trying to cool a warm house, or warm one that experiences very mild cold, but I imagine it has limited application.
- skookumchuck 8y agoAll HVAC systems must pull fresh air in from outside. Even if the ground is colder than the house, it is warmer than the air outside and so is useful to pre-heat the air. For example, if it's -10F outside, and the tubes are below the frost line, that can warm it up to 32F before needing an active heater to boost it the rest of the way.
- SketchySeaBeast 8y agoModern furnaces only pull air in from outside to burn, run through the heat exchangers, then it's blown back out - the air that's moved around inside the house is simply recirculated. Where would the air from the pilings be pulled? We would need a huge reservoir of air to prevent carbon monoxide combustion issues.
- skookumchuck 8y agoI don't think that's correct (and it's certainly not correct for my system). Not drawing in outside air from time to time will make the indoor air quality very poor.
- SketchySeaBeast 8y agoIs your furnace high efficiency? Older models take in air from the house and then blow it out the chimney, but it's different in newer systems. The intake/exhaust are both pressurized and at least exit outside the house (in most setups they pull and exit outside, but I have seen where the intake is inside). The cold air return is usually in the basement and then just blows hot around your house. And yes, the air does get stale in winter.