@article{MuellerLeiseLorenzetal.2020,
  author    = {M{\"u}ller, Tim M. and Leise, Philipp and Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.},
  title     = {Optimization and validation of pumping system design and operation for water supply in high-rise buildings},
  series = {Optimization and Engineering},
  volume    = {2021},
  journal   = {Optimization and Engineering},
  number    = {22},
  publisher = {Springer},
  issn      = {1573-2924},
  doi       = {10.1007/s11081-020-09553-4},
  pages     = {643 -- 686},
  year      = {2020},
  abstract  = {The application of mathematical optimization methods for water supply system design and operation provides the capacity to increase the energy efficiency and to lower the investment costs considerably. We present a system approach for the optimal design and operation of pumping systems in real-world high-rise buildings that is based on the usage of mixed-integer nonlinear and mixed-integer linear modeling approaches. In addition, we consider different booster station topologies, i.e. parallel and series-parallel central booster stations as well as decentral booster stations. To confirm the validity of the underlying optimization models with real-world system behavior, we additionally present validation results based on experiments conducted on a modularly constructed pumping test rig. Within the models we consider layout and control decisions for different load scenarios, leading to a Deterministic Equivalent of a two-stage stochastic optimization program. We use a piecewise linearization as well as a piecewise relaxation of the pumps' characteristics to derive mixed-integer linear models. Besides the solution with off-the-shelf solvers, we present a problem specific exact solving algorithm to improve the computation time. Focusing on the efficient exploration of the solution space, we divide the problem into smaller subproblems, which partly can be cut off in the solution process. Furthermore, we discuss the performance and applicability of the solution approaches for real buildings and analyze the technical aspects of the solutions from an engineer's point of view, keeping in mind the economically important trade-off between investment and operation costs.},
  language  = {en}
}
@inproceedings{RauschLeiseEdereretal.2016,
  author    = {Rausch, Lea and Leise, Philipp and Ederer, Thorsten and Altherr, Lena and Pelz, Peter F.},
  title     = {A comparison of MILP and MINLP solver performance on the example of a drinking water supply system design problem},
  series = {ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering},
  booktitle = {ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering},
  editor    = {Papadrakakis, M. and Ppadopoulos, V. and Stefanou, G. and Plevris, V.},
  isbn      = {978-618-82844-0-1},
  pages     = {8509 -- 8527},
  year      = {2016},
  abstract  = {Finding a good system topology with more than a handful of components is a highly non-trivial task. The system needs to be able to fulfil all expected load cases, but at the same time the components should interact in an energy-efficient way. An example for a system design problem is the layout of the drinking water supply of a residential building. It may be reasonable to choose a design of spatially distributed pumps which are connected by pipes in at least two dimensions. This leads to a large variety of possible system topologies. To solve such problems in a reasonable time frame, the nonlinear technical characteristics must be modelled as simple as possible, while still achieving a sufficiently good representation of reality. The aim of this paper is to compare the speed and reliability of a selection of leading mathematical programming solvers on a set of varying model formulations. This gives us empirical evidence on what combinations of model formulations and solver packages are the means of choice with the current state of the art.},
  language  = {en}
}