A Multiobjective Optimization Approach to a Design Problem of Heat Insulation for Thermal Distribution Piping Network Systems

A multiobjective optimization method is applied to a design problem of heat insulation for thermal distribution piping network systems. As the system’s multiple design objectives, the following two mutually conflicting and noncommensurable objective functions are considered simultaneously: (a) minimization of the total amount of heat loss from the whole system, and (b) minimization of the total volume of heat insulating material installed into the whole system. First, for a piping system of fundamental network structure, the set of Pareto optimal solutions is derived for the optimal design problem mentioned above by adopting the weighting method and the generalized reduced gradient algorithm. Second, for the purpose of investigating the same problem for piping systems of more complex network structure, a computer-aided interactive planning system is developed based on decomposition and coordination principles in the theory of hierarchical multilevel systems. Lastly, the validity and the effectiveness of the optimal design method proposed here are ascertained through numerical studies for some typical piping network systems.