Study on the Influential Factors of Heat Transfer of Ground Heat Exchanger with Orthogonal Test

Abstract

Orthogonal test method could decrease experimental times and obtain better test effect. The Taguchi method, as well as mean value response and analysis of variance, were applied in this paper to study the influence of water flow velocity in pipe, diameter and water temperature of pipe inlet on heat transfer of ground heat exchanger. The optimum design parameters and the estimated values of heat flux per meter of well depth for single U-tubes are obtained. The analysis revealed that diameter is the most influential parameter for heat flux per meter of well depth in single U-tubes while water flow velocity within 0.3m/s to 0.5m/s. And water flow velocity and diameter are important influential parameters for heat flux per meter of well depth in single U-tubes while water flow velocity within 0.5m/s to 0.8m/s. Tubes with big diameters are superior to tubes with small diameters in the design of ground source heat exchanger with single U-tubes.