A Multi-Criteria Analysis of Bidirectional Solar District Heating Substation Architecture
Abstract
Decentralized surplus feed-in of solar heat into a District Heating Network (DHN) is here addressed. The heat collected from solar panels located on rooftops of DHN connected buildings may either be used locally for domestic hot water and space heating or fed into the heating network. Two-way substations able to transfer heat from and into the network seem then to be required utilities of future DHN. In that context, two equally important questions were identified: i) what should be the specifications and architecture of such solar fed bidirectional substations? and ii) what is the impact of decentralized reinjection on the network operation? The former is addressed in the present paper while the latter is an ongoing study not presented here. In the present work, first a discussion on the specifications and architecture of such bidirectional substations led to the conclusion that architectures for which the solar heat is entirely reinjected into the DHN without local consumption seem more feasible. Second, a Modelica-based modeling framework of the bidirectional substation is presented and preliminary results highlight the potential of reinjection on the DHN. The results presented here are part of the first year work in the frame of the European project ‘THERMOSS’.