Optimization heat exchanger design

Fax, D. H. and Mills, R. R., "Generalized Optimal Heat Exchanger Design", Trans. ASME. April 1957, p 653... 

Optimal Shell-and-Tube Heat Exchanger Design. 422... 

EXAMPLE 11.2 OPTIMAL SHELL-AND-TUBE HEAT EXCHANGER DESIGN... 

Table 11.2B lists the specifications for a typical exchanger, and Table 11.2C gives the results of optimization for several cases for two standard tube lengths, 8 and 12 ft. The minimum cost occurs for a 12-ft tube length with 64 tubes (case 3). Many commercial codes exist to carry out heat exchanger design. Search the Web for the most recent versions. 

T. K. Pho and L. Lapidus. Topics in computer-aided design Part II. Synthesis of optimal heat exchanger networks by tree searching algorithms. AlChEJ., 19 1182,1973. 

Pho, T.K. and Lapidus, L., "Topics in Computer-Aided Design Part II. Synthesis of Optimal Heat Exchanger Networks by Tree Search Algorithms," AlChE Journal, Vol. 19, No. 6, pp 1182-1189, November 1973. 

The results presented In Table III show that as the capital Investment in the tower (Ztower) increases at larger tower heights, the available-energy destruction decreases. Thus the optimal design reflects the classical trade-off between capital investment and fuel cost. It is important to note that heat exchanger design plays a major role in separation systems (16). 

Development of equations for optimization of heat-exchanger design... 

TUBE-SIDE POWER COST IMMATERIAL. Optimization of the heat-exchanger design for this situation is based on the assumption that C, is zero and ht is constant. The procedure is similar to that for the case of shell-side power immaterial as described in the preceding paragraph. The optimum value of h0 can be determined from the following equation, which is obtained by setting the partial derivatives of Eq. (44) with respect to hQ and with respect to A, equal to zero ... 

Optimize the heat exchanger design of Example 4.5 to minimize the total surface area required. 

The geometry of coiled-tube heat exchangers can be varied widely to obtain optimum flow conditions for all streams and still meet heat transfer and pressure drop requirements. However, optimization of a coiled-tube heat exchanger design is very involved and complex. There are numerous variables, such as tube and shell flow velocities, tube diameter, tube pitch, and layer spacer diameter. Other considerations include single-phase and two-phase flow, condensation on either the tube or shell side, and boiling or evaporation on either the tube or shell side. Additional complications come into play when multicomponent streams are present, as in natural gas liquefaction, since mass transfer accompanies the heat transfer in the two-phase region. 

The design of the heat exchanger network is greatly simplified if the design is initialized with an optimized value for... 

Heat Exchanger Network Design Based on the Optimization of a Reducible Structure... 

The approach to heat exchanger network design discussed so far is based on the creation of an irreducible structure. No redundant features were included. Of course, when the network is optimized, some of the features might be removed by the optimization. The scope for the optimization to remove features results from the assumptions made during the creation of the initial structure. However, no attempt was made to deliberately include redundant features. 

Eurther research on convective transport under low Reynolds number, quasicontinuum conditions is needed before the optimal design of such a micro heat exchanger is possible. The cooling heat exchanger is usually thermally linked to a relatively massive substrate. The effects of this linkage need to be explored and accurate methods of predicting the heat-transfer and pressure-drop performance need to be developed. 

---