) is the welded plate cost relation, scaled to pass through a vendor cost quote. Cost relations showing an r 2 value are derived from printed plots. All relations are cost adjusted for stainless steel tubing or plates. The shell and tube heat exchanger costs allow for at least 5 MPa fluid pressure. Figure shows that the heat exchanger relationships provided by Peters (2003) and NETL (2002) are linear relationships with heat exchange area. Conversely, the relations provided by GETEM and Smith (2016) have non-linear relationships with heat exchange area. It is a common first-approximation to size equipment using a scaling exponent less than one (i.e. non-linearly), as is the case of GETEM and Smith (2016). However, Peters (2003) and NETL ( ) both provide cost estimate data points from underlying data that scale linearly, while GETEM provides no supporting data. Thus, the data support a linear scaling of heat exchanger cost with heat exchange area and we adopt the linear relationships of Peters (2003) in genGEO.