Accessibility analysis of district heating loop networks based on genetic algorithms

Aimed at district heating loop networks, a concept of accessibility analysis was established, and a mathematical model was set up, which is a max min optimum problem with nonlinear constraints. Three theorems on loop networks were presented, based on which the model was simplified. A new procedure to solve the problem based on variants of canonical genetic algorithms (VCGA) was introduced in detail. According to the accessibility analysis, the rebuilding method and the optimum operating module can be obtained to loop networks. A conclusion was drawn in engineering practices that great pumping energy saving opportunities exist to a loop network if valves in each loop can be adjusted suitably with accessibility analysis. This procedue were applied in several large district heating networks in China.