A simplified approach for energy system design in buildings and its application to a case study

The present study proposes an easy-to-use procedure for the preliminary design of energy systems for existing buildings based on easily available consumption data. The approach is then applied to a case study represented by the Rector's headquarter of the University of Cagliari. With the aim of analysing a complex case, the building has been chosen among those with unknown thermal and electrical load subdivision. The feasibility study and subsequent preliminary sizing of a Combined Heat and Power (CHP) system serving the building started through seasonal comparison of electricity consumption data, which also allowed for the subdivision of the building's electrical and thermal loads and the definition of the electrical base load. The design of the cogeneration system was conducted through the analysis of the electric and thermal demand of the building with quarter-hour resolution, compared among different seasons. The application of the model to the case study allowed for a preliminary design and techno-economic feasibility assessment of implementing a Combined Cooling, Heating and Power (CCHP) system. Besides highlighting the valuable insights that can be obtained through observation and analysis of energy power curves, this paper presents energy indicators that can be utilized to populate benchmarks' databases for comparable buildings.