The listed former waterworks Teufelssee is to be refurbished energetically and functionally as a BENE lighthouse project. The energy is supplied via heat generation using solar-air absorbers in combination with an ice storage system integrated into the building fabric. As a result, in addition to the actual renovation of buildings, this project implements an innovative and outstanding energy concept throughout Germany, which combines and illustrates the future topics of climate protection, water, preservation of cultural heritage and ecology at construction in a unique combination. The facilities and their functions are carried out in such a way that they can be experienced by visitors and integrated into the educational concept of Ökowerk e.V.