You can still get the most advanced book available on the subject, Passive Annual Heat Storage - Improving the Design of Earth Shelters, by John Hait, the pioneer in Passive Annual Heat Storage. Learn the principles of natural heat flow physics that never change. Apply your knowledge to your own home.
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"Earth Tube Ventilation
Earth tubes are excellent heat exchangers for earth bermed homes. As in the heat exchangers discussed in the previous chapter, earth berm house earth tubes will either warm or cool the air that enters them. Actually, the air which enters is moderated to nearly match the temperature of the earth around the earth berm houses.
Basically, an earth berm house earth tube is a pipe between 4 and 18 inches (10 46 cm) in diameter and at least 60 (18 m), but usually 100 or more feet (30+ m) long. They are buried in the ground, with one end inside earth bermed homes, and the other outside. They can be made out of almost any kind of pipe. Thin wall PVC is a favorite, since it has all its seams sealed to prevent unwanted things like roots and moisture from entering, and it is relatively inexpensive.
The Camel's Nose
Interestingly, there is quite a similarity between the heat exchange function of an earth berm house earth tube and the operation of a camel's nose! No kidding, a camel's nose has a lot to do with earth berm houses earth tubes.
Maybe you haven't studied a camel's nose very closely. But it is his big and unusual nose that gives him his or unique ability to go for long periods of time without water, and to maintain a constant body temperature even in extreme climates. The camel's nose is an extremely efficient counterflow heat exchanger.
[Fig. 44]
Unlike most man made heat exchange, the heat transfer in a camel's nose occurs, not between two fluids traveling in opposite directions, but from a single fluid (air) into thermal storage (the passages of the nose) when he is inhaling, and back out again when he exhales. Whether it is warm or cold outside, the air enters the lungs at about body temperature, because the heat is stored in the nose between successive breaths and returned to wherever it came from.
Earth bermed homes' earth tubes are also very effective at storing and retrieving heat just like a camel's nose. (fig. 44) And like a camel, earth berm houses should be kept at a constant 'body' temperature, regardless of the weather. All we must do is make the earth tubes breathe."
-adapted from Chapter 7, "Earth Tube Ventilation,"of the book, Passive Annual Heat Storage Improving the Design of Earth Shelters, by John Hait.
