TESPy: Thermal Engineering Systems in Python. TESPy (Thermal Engineering Systems in Python) provides a powerful simulation toolkit for thermal process engineering, for instance power plants, district heating systems or heat pumps. With the TESPy package it is possible to design plants and simulate stationary operation. From that point, part-load behavior can be predicted using underlying characteristics for each of the plant’s components. The component based structure combined with the solution method o er very high exibility regarding the plant’s topology and its parametrisation. An extensive online documentation is provided at Witte (2020). Several examples and tutorials on how to use the software are included, too.