Solardorf Bracht

From the end of 2015 to October 2016, a feasibility study was carried out for the Bracht district of the city of Rauschenberg on the local heating supply of buildings from renewable energies. In addition to an inventory of the buildings and heating systems via questionnaires, several technology options for a central heat supply were considered and compared. On the basis of the feasibility study, it was decided to pursue a particularly environmentally friendly and innovative variant with a large solar thermal field and a seasonal heat accumulator. The entire heat requirement of the buildings is to be covered 100% by solar heat. For this purpose, a working group on solar heat supply was formed in Bracht. According to a survey, around 45% of homeowners are already interested in having the solar heating network connected.

However, the planned "Solardorf Bracht" concept still has potential for optimisation. On the one hand, economically accessible renovation potentials of the buildings to be connected to the local heating network were not taken into account and the plant for regenerative heat supply was therefore too large. On the other hand, the system concept itself can also be improved. For example, the use of heat pumps could increase the temperature spread in the seasonal heat accumulator and thus also the specific storage capacity, thereby reducing the storage volume.

The optimisation potential of the "Solardorf Bracht" concept is now being examined in more detail in an extended feasibility study by the University of Kassel. The client and project partner, the State Energy Agency (LEA), will initially advise homeowners individually and free of charge and identify economically feasible renovation potentials for the buildings in the grid area. The determined saving potentials of the heat demand flow also into the extended feasibility study of the University of Kassel and form the basis for the development of renovation scenarios with in each case different heat demand reductions and conversion costs. The preparation of a heat atlas Bracht serves the visualization of the locally occurring heat demand and the local heat network preliminary design. Variants of the technically improved plant concept are designed on the basis of dynamic annual simulations. The aim of the study is to reduce the system costs of the solar heat supply as far as possible. The cost reduction influence of an economically viable refurbishment by the grid connection users is also taken into account here.