Implementation of large solar thermal system into district heating network in Chemnitz (Germany)
Abstract
The interest on solar thermal systems in district heating networks has been growing all over the world for several years. The integration of solar heat into the district heating network along with the conventional combined heat and power plant requires special concepts. This contribution describes the recent implementation of a large-scale solar heating system into a low-temperature network in the city center of Chemnitz. The technical specification of different subsystems such as the solar collector fields, the two-zone thermal energy storage and the heat transfer substation for auxiliary heating is presented. Special features of this plant are e.g. the use of water in the complete system and the extraction of heat from the return line of the main district heating network. First monitoring results are presented for the period from May to September 2017. In general, the system works as expected and a solar fraction of 21 % could be reached in the observed period. A potential for optimization is identified e.g. related to the network return temperature.