caa a22 4500 605454795 CHVBK 20210128100209.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s10064-014-0626-4 doi (NATIONALLICENCE)springer-10.1007/s10064-014-0626-4 Effect of groundwater flow in vertical and horizontal fractures on borehole heat exchanger temperatures [Elektronische Daten] [S. Dehkordi, Bo Olofsson, Robert Schincariol] Vertical closed loop systems, also known as borehole heat exchangers (BHEs), are a popular way of extracting the ground source heat energy. Primary factors affecting the performance of BHEs are the thermal and hydrogeological properties of the subsurface. Groundwater flow is known to potentially influence heat transport and system performance. The effect of groundwater movement is more commonly studied under homogeneous conditions. However, in heterogeneous fractured rocks, BHEs are more common than horizontal or open loops due to lack of sufficient soil layers and productive aquifers. The finite-element modelling shows that fractures can play an important role in BHE functioning. Especially, vertical open fractures (≥1mm) near the borehole (≤10m) can have a considerable impact. Although increase in fracture aperture continuously affects the subsurface and BHE temperatures, the increase in its effect progressively lessens. Depending on the distance and aperture, one major fracture influencing the BHE operation performance can be identified; yet a larger number of fractures may govern heat transport (thermal plume outline) and thermal recovery. Individually, horizontal fractures may have less influence than vertical fractures. However, as the density of horizontal fractures increases, their impact can be major, exceeding that of fracture aperture. In particular, we propose that measurements of rock thermal properties be combined with fracture mapping, to better analyse the thermal response testing results and integrate the configuration of fractures in design and layout of the BHE(s). This is particularly valid for (vertical) fractures not intersecting with the borehole. Springer-Verlag Berlin Heidelberg, 2014 Crystalline rock nationallicence FEFLOW nationallicence Fractured rock nationallicence Groundwater flow nationallicence Heat transport nationallicence Thermal response test nationallicence Dehkordi S. Department of Earth Sciences, University of Western Ontario, N6A 5B7, London, ON, Canada aut Olofsson Bo Department of Land and Water Resources Engineering, Royal Institute of Technology (KTH), 100 44, Stockholm, Sweden aut Schincariol Robert Department of Earth Sciences, University of Western Ontario, N6A 5B7, London, ON, Canada aut Bulletin of Engineering Geology and the Environment Springer Berlin Heidelberg 74/2(2015-05-01), 479-491 1435-9529 74:2<479 2015 74 10064 https://doi.org/10.1007/s10064-014-0626-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10064-014-0626-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dehkordi S. Department of Earth Sciences, University of Western Ontario, N6A 5B7, London, ON, Canada aut NATIONALLICENCE 700 1- Olofsson Bo Department of Land and Water Resources Engineering, Royal Institute of Technology (KTH), 100 44, Stockholm, Sweden aut NATIONALLICENCE 700 1- Schincariol Robert Department of Earth Sciences, University of Western Ontario, N6A 5B7, London, ON, Canada aut NATIONALLICENCE 773 0- Bulletin of Engineering Geology and the Environment Springer Berlin Heidelberg 74/2(2015-05-01), 479-491 1435-9529 74:2<479 2015 74 10064