We infer from Fig. that the only difference between the two TDF setups is the surface location of the power plants and piping, for the assumptions (e.g., a homogeneous, horizontal-isotropic, laterallyextensive reservoir) utilized in this study. Therefore, we conclude that the reservoir impedance and the thermal recovery will be the same in a TDF full of five-spots as a TDF full of doublets, and the analysis of a five-spot TDF applies equally to a doublet TDF. We do not distinguish between a 5-spot TDF and a doublet TDF for the rest of the paper. From a practical standpoint, it is advantageous to build surface infrastructure as a TDF doublet pattern rather than a TDF 5-spot pattern because it reduces the amount of piping to bring fluid to and from the powerplants. The piping required for one unit of a doublet TDF has an approximate length of 𝐿, whereas the piping needed for one unit of a 5-spot TDF has an approximate length of 4𝐿, as can be seen in Fig. .