2002 Volume 24 Issue 4 Pages 365-371
We constructed combination piping system of 1 m depth horizontal line and 3 m depth wells (cascade type) for heat extraction from shallow underground. Total length is 180 m and expected heat extraction is 1.4 kW or more. This system was formed by use of popular civil engineering machines with very low cost and easy operation. Area need for this system is only 18 m2 and possible to construct in land spaces of average Japanese private houses. Underground temperatures of 16.2 and 9.3°C are maximum and minimum at 4 m depth for over one year record (from May 2001 to July 2002) . Based on these underground temperatures and high ground water level, our piping system have enough heat extraction capacity for small house cooling/heating. We just install heat pump and start long term experiment.
