Optimization of layout and diameter for distributed solar heating network with multi-source and multi-sink

A distributed solar heating system (DSHS) connects solar heat users who both produce and consume heat, taking advantage of the difference and complementarity in heat demand among users to improve system efficiency. The pipe network of the DSHS has the characteristics of bidirectional flow, and the existing unidirectional network design method from heat source to users cannot be applied to the bidirectional-flow network. This paper developed an optimization model for the network layout and the pipe diameter by minimizing the total annualized costs (TAC). The model was solved using an improved integer-coding genetic algorithm, which realized the collaborative optimization of the network layout and pipe diameter. The same results were obtained by applying the exhaustive method and the proposed method for a case study, which verified the effectiveness of the proposed method. Compared to the conventional design method, the proposed optimization model resulted in a 4.9% savings in TAC. A parametric analysis showed that pipeline price affects design results when annualized network con-struction costs, operating costs and heat loss costs are comparable. The method proposed in this study can be used to effectively design the network of DSHS, and provides a reference for the further devel-opment of DSHS.(c) 2022 Elsevier Ltd. All rights reserved.