Heat Exchange Mechanisms in Energy Quay Walls: Field Observations and Numerical Analysis

M. Gerola1, F. Cecinato1, J.K. Haasnoot2, P.J. Vardon3
1Earth science “A. Desio” department, University of Milan
2CRUX Engineering BV
3Faculty of Civil Engineering and Geosciences, Delft University of Technology
Published in 2023

The increasing demand for energy and the need to reduce reliance on fossil fuels in response to climate change have spurred the exploration of renewable energy sources. Energy Geostructures address these issues by providing at the same time mechanical support to overlying structures and/or soil and geothermal energy for space heating and cooling. Energy sheet pile walls (ESPs) are a novel form of EGs that utilize sheet pile walls fitted with steel pipe heat exchangers. When used along quays, ESPs are known as Energy quay walls (EQWs), offering the advantage of extracting thermal energy from both soil and water. However, the thermal and thermo-mechanical behavior of EQWs is not well understood due to the absence of standardized design methods. Based on a test case installed in Delft (NL), this study focuses on the thermal behavior of EQWs and presents two Finite Element (FE) numerical models. To investigate the initial temperature distribution prior to the thermal activation of the EQW, required to simulate the thermal operation of the EQW, and to conduct a comprehensive analysis of the EQW's thermal performance, two numerical models were constructed using the COMSOL Multiphysics® software using the "Heat Transfer in Porous Media" and "Heat Transfer in Pipes" interfaces. The first model focuses on evaluating the temperature distribution in the soil prior to the thermal activation of the EQW, which serves as initial conditions in the subsequent thermal operation numerical model. The thermal operation model successfully reproduces both the temperature at the heat pump's inlet and the temperature variations within the soil. The FE models allowed for a thorough examination of the heat exchange phenomena within the EQW, providing valuable insights into its thermal performance.