Design Considerations for Borehole Thermal Energy Storage (BTES): A Review with Emphasis on Convective Heat Transfer

Figure 5

Different array shapes for BTES thermal energy storage. (a) Two BHE spaced >20 m apart will typically not thermally interfere with each other; (b) if the spacing is <10 m, however, thermal interference can become significant (depending on thermal energy loadings). (c) A linear array of closely spaced BHE will not be especially efficient at storing heat, due to the large perimeter through which heat can be lost. (d) A more “closed” array shape, such as a square grid of BHE, will be more efficient at storing heat, although (e) larger hexagonal or cylindrical arrays will be even more efficient, due to the declining ratio of surface area to volume as array size increases.

(a)

(b)

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(d)

(e)