Seasonal Thermal Storage

 
                MIT's Solar 1 House 1939                                    Solar 1  Crossection



"ANNUALIZED GEO-SOLAR HEATING" AS A SUSTAINABLE RESIDENTIAL-SCALE

SOLUTION FOR TEMPERATE CLIMATES WITH LESS THAN IDEAL DAILY HEATING SEASON

SOLAR AVAILABILITY

 

So if that soil mass were below indoor comfort temperatures, it represented a continuing heat-sink, drawing

warmth from the building. This led to a designer theory that underground structures should be insulated from

the earth around them. But experience soon suggested otherwise. We found that while an insulated earth

shelter did immediately perform better than a surface structure, requiring less energy for winter heating (and

summer cooling), it's winter performance continued to improve through the first 3 to 4 years. The conclusion

shared by many earth-sheltering researchers was that, even with the insulation between, some heat from

inside was still getting through to slowly warm the surrounding earth, and that as it did, the delta-T (the

difference between inside air and outside in-soil temperature) became smaller, so less additional heat was

being lost.

Data indicates that as far back as 1.5 million years ago, humans began bringing fire into those caves (Levin,

2005). They probably didn't realize that, in addition to the immediate warmth and cooking benefits they

derived, they were also slowly raising the holding temperature of the rock and earth masses around them.

Beneath the fire’s coals, heat was slowly conducting down and outward, radiant warmth was reaching

surrounding surfaces, and pools of heated air at ceiling level were transferring their energy to the rock mass

above. And these fires, fueled primarily by the summer growth of tree bulk, were turning that stored energy

into winter heat, while simultaneously increasing the annualized temperature of the surrounding earth mass.

For sub-structure soil to reach and maintain optimal temperatures (a several year process), it must be

buffered from winter's outdoor extremes by sub-grade perimeter insulation extensions and from precipitation transferred losses by perimeter water-diversion devices.

By Don STEPHENS, InA  Spokane WA  USA


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