Fig. 1From: An efficient hybrid model for thermal analysis of deep borehole heat exchangersSchematic of heat transfer process for deep borehole heat exchanger: inverse loop (left) and forward loop (right). Reproduced with permission from Elsevier from Bär et al. (2015); this work is licensed under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Back to article page