Developing analysis approaches for energy walls

Abstract

The use of diaphragm or bored pile walls as ground heat exchangers as well as embedded retaining structures has gained popularity in recent years. Dual use of structure foundations in this way has the potential to reduce the costs of associated ground source heat pump systems, hence providing opportunities for the take up of renewable heating and cooling in our cities. Such systems have been recently constructed as part of major infrastructure schemes in London and Paris. However, there are no standard analytical analysis approaches to permit routine design of the thermal aspects of these novel planar ground heat exchangers. Hence assessment of energy availability on most practical projects either (i) adapts existing methods from ground heat exchangers of different geometry, which runs the risk of incurring errors; or (ii) resorts to time consuming numerical simulation, often in partnership with a research organisation. Neither approach is sustainable for routine roll out of the technology beyond prestige projects. To start to fill this gap in knowledge, this paper presents the first feasibility assessment of developing specific analytical tools for use with energy walls.