“To achieve it, one builds a high-mass, UN-INSULATED (except where exposed to above-ground air-temperature fluctuations), largely earth- covered, usually poured-concrete house shell, with SEVERAL FEET of earth over it and earth against much of the walls. This is then covered with a moisture-barriered insulation “umbrella” over that roof earth and berms and extending out 20 feet (sub-grade) all around. Finally it requires a cap of sod and/or planted earth, or other durable material, protecting the umbrella from ultra-violet degradation and other trauma. With his designs, air exchange and supplemental soil heating are often achieved with thermo-driven passive air-flow through earth tubes.)”
The problem with AGS is the structure has to be built specifically to support the themal requirement.
Conventional prebuilt houses could be retrofitted with a standalone system where a large mass of earth is isolated with an umbrella that would be buried with a series of earthtubes (made out of flexible sewer pipe). The air exchange system could be a verticle axis windmill for simplicity.
Since the average for earth at depth is 58 to 62 degrees a constant slow exchange would mean that it would be impossible for a properly insulated living area to fall below that range.
The amount of warmed/cooled area would be preportional to the length of earthtube.
In America most living space seems to end up as storage space so this might be easy for a shortened system.
This does not address high humidity during the summer months and condensate that could collect in the low points of such system.
You could have the earthtubes lead to a low point and dual purpose the forced air fan in an enclosure below ground.