Configurations and exergy analysis of district heating substations based mainly on renewable energyY.J. Gao, S.G. Wang, S. Jiang, X.Z. Wu, J.H. Wang, T.F. Zhang and Z.J. MaE3S Web Conf., 356 (2022) 01005DOI: https://doi.org/10.1051/e3sconf/202235601005