6 Multi-Borehole Heat Exchanger Arrays

The focus of this chapter is the design and dimensioning of vertical bore ground heat exchangers (GHXs) coupled to heat pump applications. GHXs consist of multiple BHEs connected together. For example, residential buildings may require 3–5 vertical BHEs, while larger buildings such as schools may require tens to hundreds. In this chapter, we will use the term vertical ground heat exchanger (or GHX) to refer to the entire array of BHEs, meaning that the GHX length (L) will now be defined to mean the total number of boreholes (NB) × the borehole depth (H).