Subsoil levels are used as a heat sink to receive or supply heat via concentric tubes set vertically or obliquely into the ground and through which a heat exchange fluid (I) is circulated. Pref. used to collect heat from solar energy traps during daytime or summer periods and release heat overnight or during the winter, depending upon the cycle times and thermal capacity employed. The buried tubes may be of metal or plastic, opt. are linked by pipes set in trenches typically 50 cm deep. Opt. (I) is an antifreeze liquid.
展开▼
