  In the presented study, a pipe penalization approach for the economic
topology optimization of District Heating Networks is proposed, drawing
inspiration from density-based topology optimization. For District Heating
Networks, the upfront investment is a crucial factor for the rollout of this
technology. Today, the pipe routing is usually designed relying on a
linearization of the underlying heat transport problem. This study proposes to
solve the optimal pipe routing problem as a non-linear topology optimization
problem, drawing inspiration from density-based topology optimization. The
optimization problem is formulated around a non-linear heat transport model and
minimizes a detailed net present value representation of the heating network
cost. By relaxing the combinatorial problem of pipe placement, this approach
remains scalable for large-scale applications. A discrete network topology and
near-discrete pipe design is achieved by using an intermediate pipe
penalization strategy. For a realistic test case, the proposed algorithm
achieves a discrete network topology and near-discrete pipe design that
outperforms simple post-processing steps.
