... A fixed sum of money may also be 94 Design and Optimization of Thermal Systems 74 10 19 47 31 29 44 18 46 49 28 27 17 11 26 48 42 43 32 16 33 41 12 14 13 FIGURE 2. 25 The first page of a typical ... 80 Design and Optimization of Thermal Systems quantities may be given in terms of the design variables and the operating conditions, for given fluids, as Q F (D1, D2, L, t1, t2, m1 , m2 , T1,i, ... D1 and D and the length L, and for different operating conditions, including off -design, given by the flow rates m1 and m2 and the inlet temperatures T1,i and T2,i Basic Considerations in Design...