A newly developed procedure, accessibility analysis of district heating (DH) networks, is presented in this paper. Based on the analysis, the hydraulic conditions can be optimized. The mathematical model is established based on graph theory and the basic principles of hydraulic network. For a loop network, it is a maximum-minimum optimum problem with nonlinear constraints. Based on genetic algorithms (GA), a new method to solve it is introduced in detail. The concept of accessibility analysis simultaneously reduces pumping energy consumption and meets flow rate demands, and it has been applied in dozens of large district heating networks in China. A case study is illustrated and discussed.

Units: SI