Optimization of Closed-Loop Shallow Geothermal Systems Using Analytical Models

TL;DR

This paper presents an analytical modeling approach to optimize the design of closed-loop shallow geothermal systems, specifically vertical borehole heat exchangers, considering regulatory temperature constraints to improve planning accuracy.

Contribution

It introduces a novel analytical method combining finite line source and borehole heat transport models for optimal BHE field design.

Findings

Effective optimization of BHE configurations demonstrated.

Temperature constraints incorporated into the design process.

Potential to enhance current geothermal system planning practices.

Abstract

Closed-loop shallow geothermal systems are one of the key technologies for decarbonizing the residential heating and cooling sector. The primary type of these systems involves vertical borehole heat exchangers (BHEs). During the planning phase, it is essential to find the optimal design for these systems, including the depth and spatial arrangement of the BHEs. In this work, we have developed a novel approach to find the optimal design of BHE fields, taking into account constraints such as temperature limits of the heat carrier fluid. These limits correspond to the regulatory practices applied during the planning phase. The approach uses a finite line source model to simulate temperature changes in the ground in combination with an analytical model of heat transport within the boreholes. Our approach is demonstrated using realistic scenarios and is expected to improve current practice in the planning and design of BHE systems.