Operational Behaviour of a Solar-Fed Bidirectional Substation for 4GDH Networks
Abstract
Decentralized feed-in of solar surplus heat from prosumers into a District Heating Network is here addressed. A specified architecture combining a Return/Supply connection, a set of valves, a feed-in pump and a primary side connection of the solar field led to the conception and fabrication of a bidirectional substation prototype. The latter is tested in a hardware-in-the-loop configuration regarding the consumer and solar field sides while the DHN side of the substation prototype is connected to a real DHN. A 12-days sequence, representative of typical days, with varying solar irradiation, DHN thermo-hydraulic conditions and consumer demands is performed with the prototype. An illustrative results is shown with day 6 for which the controller is shown to have an efficiency of 98.7% for a total solar fraction of 25.5%.