WCR Investments Limited (WCR) appointed ESI Ltd to undertake an options appraisal for the installation of a carbon efficient and cost effective heating/cooling system for some new commercial office spaces that are being developed at the Parklands Site, Bristol. The main objectives were to assess the technical and economic feasibility of a Ground Source Energy system, based on an understanding of the site acquired from ESI’s Phase I and Phase II contaminated land studies.
Several tasks were undertaken in order to fulfil the objectives, including:
Collation of data from previous studies and newly acquired data from the Environment Agency and British Geological Survey
Detailed assessment of the geology and hydrogeology of the area in order to define a conceptual model to support the operational and technical boundary conditions for the implementation of a ground source energy solution
Appraisal of options based on the site constraints in relation to site morphology, contamination and building footprint
Cost estimate analysis for an open loop system conducted for different scenarios based on the expected aquifer yields, including the costs for a trial borehole and subsequent pumping test
Cost estimate analysis for a closed loop system conducted for different scenarios based on potential different outcomes from a thermal response test, including the costs for a small diameter trial borehole
It was concluded that a closed loop ground energy pump solution would have provided the smallest technical risk although the initial capital costs would have been significantly higher. A groundwater energy pump solution was considered a viable option but involved higher risk due to uncertainties in relation to the aquifer yields. Therefore a recommendation for a trial borehole was submitted to the client as the next step forward.
ESI is recognised as a centre of excellence for groundwater modelling, and is contracted by both public and private organisations to carry out similar work.