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This is similar to my plan. I plan to cool and warm my house using an earth tube or two, which leaves electricity required for very modest use, lighting, chargi
by friend_and_foe 3y ago
This is similar to my plan. I plan to cool and warm my house using an earth tube or two, which leaves electricity required for very modest use, lighting, charging phones and what not and a refrigerator. Combined with a white or silver metal roof and a good gap between the solar panels to allow wind to flow through in leu of an attic should do me just fine, and on top of that the inside air will always be fresh from outside. The energy saving will be tremendous, and digging a trench for the earth tubes will actually cost less than installing a central air conditioning unit. Additionally you don't really need insulation, since fresh temperate air is always cycling in and is available pretty much endlessly, the limiting factor on efficiency is air flow, not insulation. Also, no condensation in the walls; they'll always be above the dew point in the summer, and in the winter the air will be well below 100% relative humidity since the ambient air is being warmed, not cooled, and so the walls will never be below the outside ambient temperature in the winter.
The only downsides I can see are that I can't set the temperature, it would be whatever it is in the ground, which at the right depth should be around 73F year round, and 100% relative humidity in the summer. That and that the house must be designed for maximum air flow but I don't really see that as a downside, people have designed houses this way forever until the advent of air conditioning, and to be honest I'm not a fan of a house design that doesn't take air flow into consideration.
- pengaru 3y agoI don't think earth tubes are ideal for such direct plumbing into living spaces. My understanding is that they tend to develop mold and stagnant moisture will pool in the underground portion. Imagine a hot and humid day, the humid air will condense on the cool walls while passing through the underground section of the tube. Do you really want that to be your fresh air duct? But it seems like a useful mechanism for delivering ground-coupled outdoor air to an outdoor application, which could be a heat exchanger participating in regulating indoor temperatures.
- friend_and_foe 3y agoYes, my design right now includes a HEPA filter on the intake, preventing spores from ever even getting in the tube, a slight grade downwards towards the intake and a water catchment system at the end with a float tank activated pump to pump the water out periodically.
- pengaru 3y agoI'd love to hear how that plays out after a decade of use. It's something I've considered experimenting with for a future ADU/guest-house on my desert property, but it seems too troublesome for my liking.
- friend_and_foe 3y agoYeah it sounds troublesome at first, but then you realize that digging a trench and laying some pipe is cheaper, easier and less maintenance than having a machine with moving parts and duct work and all that. In a desert I'm guessing in north america, the only things you have to consider are that the ground may be very rocky and also the pipe won't be in wet soil which will mean it will cool less quickly and you have to run a longer pipe. The good side is you're not likely to have tree roots crack the pipe and youre very likely to keep the humidity well below 100% even in the summer. I'd say go for it, deserts are very mold free. You might also consider radiative cooling with some of that super white paint that radiates heat faster than it collects, since you'll have less shadows and clouds it should radiate rather well, downside being colder nights and winters.