Borehole heat exchangers (BHE) are the most frequently adopted solution for ground coupledrnheat pump applications. In most installations, BHEs also represent the most important costrnitem, and a careful design analysis is needed to either assure long time performance or reducernthe payback period, both parameters related to overall BHE length. The most efficient way,rnfrom a computational point of view, to predict the temperature evolution in time and space ofrna ground volume in contact with a system of BHE, is the recursive calculation of a basicrnthermal response factor, evaluated at different time steps and for given different heat pulsesrnrepresenting the building energy demand. Hourly load simulations, along multiyear periods,rnare considered the most reliable approach for simulating the thermal interactions between thernground and a system of BHEs and thus simulating the ground coupled heat pump (GCHP)rnbehaviour during the expected lifetime of the whole system. Among the literature models, thernDST one is often used as the reference analysis tool. The DST model is based on a descriptionrnof the ground/BHE system in terms of interacting cylindrical volumes, arranged in a regularrngeometry. In this paper, the DST solution, in terms of hourly temperatures of the heat carrierrnfluid, is compared with the correspondent results obtained by implementing the MLAArnapproach of Bernier et Al. into a model able to employ suitable g-functions generated startingrnfrom the Finite Line Source solution of Lamarche and Beauchamp.rnThe study is aimed at comparing the predicted temperature values by the DST and MLAArnmodels with reference to different BHE configurations, having the same number of groundrnheat exchangers but different geometrical distribution (e.g. square configurations vs in-linernconfigurations)
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