Heat Transfer Performance in Energy Piles in Urban Areas: Case Studies for Lambeth College and Shell Centre UK

He Qi,Yi Zhang,Hongzhi Cui,Zhonghua Zhang,Yu Zhou,Xi Wang,Bo Wang

doi:10.3390/app10175974

He Qi, Yi Zhang + Show 5 more

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https://doi.org/10.3390/app10175974

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Abstract

A ground source heat pump system is a highly efficient renewable heating, cooling, and ventilation system that utilizes the ground as a heat source or sink via ground heat exchangers. Energy pile is an energy geotechnical structure that couples a ground heat exchanger with a geotechnical structure, leading to low capital cost. The design of energy piles can be challengeable due to their complicated geometries and the requirement of mechanical load. This study focuses on the heat transfer across the concrete–soil interface of energy piles in urban areas. Case studies from two projects, the Lambeth College and Shell Centre projects, are presented and discussed. The back analysis of two energy pile cases illustrated that the heat transfer coefficient at the pile–soil interface can differ between the cooling mode and the heating mode. It can be concluded that the difference in the heat transfer coefficient is influenced by a number of factors such as soil properties, concrete (grout) properties, and the installation method.

Highlights

The ground source heat pump (GSHP) has been widely approved as an effective and renewable technology towards energy saving and CO2 emission reduction [1,2,3]
This study focuses on the heat transfer across the concrete–soil interface of energy piles in urban areas
This study aims to illustrate the heat transfer at the concrete–soil surface of energy geotechnical structures (EGS)

Summary

Introduction

The ground source heat pump (GSHP) has been widely approved as an effective and renewable technology towards energy saving and CO2 emission reduction [1,2,3]. To install the GSHP loops into geotechnical infrastructure can avoid the borehole drilling cost so it leads to great saving for GSHP application. The TRT (Thermal Response Test) method is employed to estimate the thermal properties of energy piles [11]. There are still components of the thermal resistance that were not considered, such as the in-pipe layer resistance and the thermal resistance at the surface of the pile. If all these components are fully simulated, the TRT data could be used to determine the ground thermal properties more accurately by numerical back analysis

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