Heat exchange characteristics of spiral pile geothermal heat exchanger along flow direction

Establishes a three dimensional heat transfer model for spiral pile geothermal heat exchanger, and investigates the heat exchange and temperature distribution characteristics of the fluid along flow direction. The results show that the spiral pile geothermal heat exchanger along the fluid flow direction has four heat exchanging phases: inlet of heat exchanger, grout thermal short-circuiting, small temperature difference and outlet of heat exchanger. Each phase has its corresponding heat transfer characteristics. Reducing the length of small temperature difference phase and increasing the length of the other phases will enhance the heat exchanging capacity of spiral geothermal heat exchanger.