CFD Study of a Large Buried Tank within a Borehole Field

Abstract

This work explores the impact of burying a short term thermal storage (STTS) tank within a borehole thermal energy storage (BTES, or borehole field). There is motivation to bury tanks in order to save space on ground level, as well as to improve the overall efficiency of the system by reducing heat losses from the tank. This work mainly looks to understand the impact of the lack of boreholes under the buried tank, as well as the thermal interactions between the tank and boreholes.

Computational Fluid Dynamics was used to predict the transient temperature throughout the domain. The long-term performance was assessed by simulation a five year period. Examination of factors that influence the tank-borehole interactions was studied and it was determined that radial stratification of the borehole field as well as the soil properties have the largest influence in terms of increasing the efficiency of the BTES. Other factors, such as tank stratification and tank insulation have little impact and the remainder (tank aspect ratio, and alternate geometries) have some impact.