Study On Optimal Design Discretely Of Tree-Shaped Heat-Supply Network

The scope of district heat-supply network is increased steadily in China, and human not only demand the scope, but also require optimization for the design, operational analysis, and improvement of piping, it is necessary to combine the consideration of technology, energy and economy. For a long time, the optimal design of complicated ring-shaped heat-supply network has been a feeble tache, The traditional design only satisfied the needs of technology but dissatisfied the needs of economy. In order to improve therm-ecomomy of piping system, the discrete optimization for the design for tree-shaped heat-supply network has been deeply researched by the author of this paper. The main contents and research results are outlined as following:Firstly, the theory of optimal therm-economic synthetical design of a piping system has been proposed. This theory solves successfully the synthetical problem among technology, energy and economy of piping, and solves successfully the coupling problem between the layout structure optimization and the parameter optimization. Adopting the theory the designed piping have the property of minimum of energy loss and cost, as well as excellent technical quality.Secondly, it built a mathematic model about the whole optimal design of complicated heat-supply network. The model included diversified technical and economic targets, it regards the discrete pipe diameter as the decision-making variable and choose the year-conversion expense as the optimal objective function, at the same time, it also takes into account the side of investment, circulation and management. Constrained conditions included diversified parameters, i.e. pressure constrain and velocity constrain.Thirdly, it advanced a algorithm that applies the discrete optimization for the design for tree-shaped heat-supply network—approach inch by inch algorithm. Two new parameters about difference ratio between investment and operation, optimal difference ratio and a new concept about unconstraint are introduced, to express potential capability of energy conservation, and to adjust the bound of diameter back and forth to shorten the time of convergence.