Influence of location and design on the performance of a solar district heating system equipped with borehole seasonal storage

The solar district heating system combined with borehole thermal energy storage (BTES) in the Drake Landing Solar Community (DLSC) has managed to provide 97% of the community's annual space heating demand with solar power. Following such exceptional results, the focus of this paper is to analyse the influence of location changes on the DLSC. A model of the community is created with TRNSYS and simulations are carried out in five different locations: Helsinki [FI], Hohhot [CN], Dublin [IE], Oviedo [ES] and Perpignan [FR]. To fulfil the specific needs of each location, adaptive measures are taken by modifying key parameters of the system's original design. Results show that insulating the houses and using lower temperature heating systems can significantly increase the system's solar fraction (SF). Despite increasing SF, the use of lower temperature heating systems in well-insulated homes may result in a decrease in the BTES's efficiency (η_BTES), which is also dependent on local ground properties. In hot climates, the BTES may be omitted due to high levels of winter solar radiation. Very high SFs are found to be possible in all studied locations (>95%), as long as appropriate modifications are made to the original design when necessary.