Substations for Decentralized Solar District Heating: Design, Performance and Energy Cost

Abstract The development of solar district heating is gaining more and more interest, but, in some case the space available for the integration of solar collectors on the ground is limited and the use of decentralized systems is necessary. For decentralized solar district heating systems different hydraulic schemes at the substation level, with or without local use of solar energy, are possible. The present paper detailed an advanced study on decentralized solar district heating system using dynamic simulation software. Nine different hydraulic schemes for substations have been investigated with a return to return feed in. For each scheme many parameters that influence the performance of the solar installation have been studied such as the district heating network return temperature, the solar collector area and the type of solar collector (low temperature or high temperature solar collector). The comparison between the different hydraulic schemes is based on thermal efficiency but also on solar energy cost using the methodology of the Levelized Cost Of Energy (LCOE).