Globally optimal design of intensified shell and tube heat exchangers using complete set trimming

Abstract

Intensified shell and tube heat exchangers have been proposed for their use in the grassroots and retrofit designs of heat exchanger networks. Among them are those featuring helical baffles, externally and internally finned tubes, twisted-tape inserts, coiled-wire inserts, and twisted-tube exchangers. Some of these devices are suited for the tube side and others for the shell side, while the utilizations of different devices on both sides simultaneously are also possible. The optimal design of these exchangers has been attempted by several authors using different techniques with varied successes. In particular, finding local solutions require good initial points. Also, global solutions using global solvers are completely elusive. In the present work, we study the computational performance of the use of Complete Set Trimming to obtain the globally optimal design of intensified heat exchangers featuring the minimum capital cost and total annualized cost. The results of examples indicate the Set Trimming competes well with commercial global solvers that are highly time-consuming or sometimes incapable of solving the design problem.