A different use for earth tubes or pipes
I have been intrigued for a while by the potential of Earth Tubes (most significantly discussed here at: https://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/my-earth-tube-story’rel=”My Earth Tube Story”‘. I have a project coming up that will involve regrading, earth fill, and irrigation installation on a sloped half acre, so I may have the opportunity to bury some pipe (4-6ft deep, climate zone on the line of 5/6), if it seems worthwhile.
It seems the biggest negative for earth tubes is controlling air quality — which is assuming you want to pull that air into the house. What about NOT pulling it into the house?
1. Would there be any value to having cheap earth tubes open at an outdoor condenser unit, to provide a supply of more conditioned air for the heat pump to transfer heat to and from, mitigating hot and cold days?
2. Failing that, could sufficient air be supplied to provide a cool breeze to a patio or deck?
1 and 2 require calculating the amount of air flow that could be drawn through the pipe, and then what the blower could move (or the condenser fan on the heat pump–definitely would not want to stress that fan by choking it!), and of course how much of a difference the heat transfer would make. I’m not sure what variables I need to calculate all that. Volume of the pipe is easy, but heat transfer and how much air supply would be needed for fans to not be stressed, I don’t know.
3. What about using buried water pipes and a hydronic water-air heat exchanger that DOES go inside the house and have air blown across? Possibly matched to a spare water tank (from an old hot water heater) and a recirculating pump on a thermostat?
Could recirculating water through such a system condition enough air to be worth it?
What if the pipe already being buried for an irrigation system could also be used in a loop to recirculate this water (thus improving the economics)?
Yes, for that to work, there would have to be some way to charge the main supply line without activating the sprinkler heads…wondering if that could be done by some kind of pressure regulator valve on the risers, with pressure being low during circulation and high when the sprinkler needs to run.
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