Constructability and heat exchange efficiency of large diameter cast-in-place energy piles with various configurations of heat exchange pipe

摘要: Abstract A new ground heat exchanger (GHEX) assembled in a source pump (GSHP) system has been devised, which is equipped structural pile, and thus called an “energy pile”. In this study, six large-diameter cast-in-place energy piles that encased various types of exchange pipes (i.e., three parallel U-types with 5 pairs, 8 pairs 10 pairs; two coil-types 200 mm coil pitch 500 mm pitch; S-type) were constructed test bed, the constructability each type pile was compared. Additionally, 30 m-deep closed-loop vertical GHEX separately to compare thermal performance economic feasibility piles. series in-situ response tests (TRTs) performed evaluate relative efficiency according pipe configurations. The obtained down-sized normalized by length (or borehole length) total length. result from indicates longer installed, higher per However, case tight layouts pipe, interference occurs between adjacent loops, decreases efficiency. Economic evaluated, considering material installation costs for assembling consideration It concluded coil-type can achieve sufficient capacity exchange, compared GHEX.