Energy and cost optimization of shell and tube heat exchanger with helical baffles using Kriging metamodel based on MOGA

In order to overcome the dependence on empirical correlations and to achieve a more accurate results for modeling the computer response, an improved algorithm combing a Kriging response surface and the multi-objective genetic algorithm (MOGA) for the optimization design of shell and tube heat exchanger with helical baffles (STHXsHB) is proposed in this paper. The helical angles β, baffle overlap proportion e and inlet volume flow rate V are considered as optimization parameters, in which the heat transfer rate and total cost are optimized by multi-objective optimization. The results show that compared with the real solutions of CFD simulation, the optimized results illustrated a good agreement within ±3% error. Therefore, the optimization method is verified to be successful. Besides the obtained Pareto-optimal points show that a small helical angle with 15° and the baffle overlap proportion is equal to 0.25 are beneficial to trade off the heat transfer rate and total cost of STHXsHB. Furthermore, the comparison between the optimum STHXsHB and a conventional shell and tube heat exchanger with segmental baffles (STHXsSB) are carried out. The results show that the comprehensive performances of the optimum STHXsHB are better. The evaluation index PE_A and PE_B increase by 76.5-91.2% and 69.0-84.5%, respectively. Therefore, it can be concluded that employed helical baffles in the STHXs can obtain a better performance. Moreover, this new method can be used to optimize the STHXsHB and the conclusions are benefit in the design of STHXsHB for energy saving and cost reduction.