Interaction Effects Between Aquifer Thermal Energy Storage Systems

Abstract

Aquifer thermal energy storage (ATES) is an energy efficient technique to provide heating and cooling to buildings by storage of warm and cold water in aquifers. In regions with large demand for ATES, ATES adoption has lead to congestion problems in aquifers. The recovery of thermal energy stored in aquifers can be increased by reducing the distance between wells of the same temperature while safeguarding individual system performance. Although this approach is implemented in practice, the understanding of how this affects both the recovery efficiency and the needed pumping energy is lacking. In this research, the effect of well placement on the performance of individual systems is quantified, and guidelines for planning and design are developed. Results show an increase in thermal recovery efficiency of individual systems when the thermal zones of wells of the same temperature are combined, which is explained by reduced surface area of the thermal zone over which losses occur. The highest increase of the thermal recovery efficiency is found for systems with a small storage volume and long well screens. The relative increase of the thermal recovery efficiency is 12% for average-sized systems with a storage volume of 250,000 m 3 /year, and 25% for small systems (50,000 m 3 /year). The optimal distance between wells of the same temperature is 0.5 times the thermal radius, following the trade-off between an increase of the thermal recovery efficiency and the increase in pumping energy. The distance between wells of opposite temperature must be larger than three times the thermal radius to avoid negative interaction.

Machine Learning for Bayesian Experimental Design in the Subsurface

“…Such systems use thermal energy extracted from the ground or groundwater to heat or cool buildings, which necessitates some electrical energy input for the heat pump, while storing the excess heat or cold underground. The goal is to re-use this thermal energy during the next season in a cyclic utilization (Bayer et al, 2013;Duijff et al, 2021;Saner et al, 2010;Vanhoudt et al, 2011). The performance of BTES and ATES strongly depends on the subsurface properties.…”

City-scale heating and cooling with Aquifer Thermal Energy Storage (ATES)

“…After the tenth cycle, however, no further increase of TR was observed during simulations. This is in good agreement with statements from previous studies (Bakr et 255 al., 2013;Duijff et al, 2021;Sommer et al, 2013). Accordingly, the representative TR value used for further evaluation equals the average of TR for the warm and the cold well(s) for the tenth complete cycle, i.e.…”

“…In this study, we assume a typical coefficient of performance COP = 3.5 (Bayer et al, 2012;Born et al, 2022;Duijff et al, 2021;Saner et al, 2010). This results in the factor fHP = 1.4.…”

“…Furthermore, deliberate thermal interferences between wells of the same type, i.e. wells of either the warm or the cold storage areas, can decrease thermal loss at the storage volume boundaries due to a better ratio of storage surface area to storage volume (Bloemendal et al, 525 2018;Duijff et al, 2021;Pellegrini et al, 2019). Expanding on this study's modeling approach aimed at ATES potential determination, a city specific optimization of ATES placement in Freiburg could account for such positive thermal interferences, while also including existing shallow GWHP systems.…”

Comparing Well and Geophysical Data for Temperature Monitoring Within a Bayesian Experimental Design Framework

“…Such systems use thermal energy extracted from the ground or groundwater to heat or cool buildings, which necessitates some electrical energy input for the heat pump, while storing the excess heat or cold underground. The goal is to re‐use this thermal energy during the next season in a cyclic utilization (Bayer et al., 2013; Duijff et al., 2021; Saner et al., 2010; Vanhoudt et al., 2011). The performance of BTES and ATES strongly depends on the subsurface properties.…”