Development of sustainable energy options for buildings in a sustainable society

In this study, a building with a volume of 392 m3 and a net floor area of 140 m2 is considered as a case study with the indoor and exterior air temperatures of 20 °C and −15 °C, respectively. For heating applications, seven options are studied, namely (i) electric boiler, (ii) cogeneration, (iii) biomass/wood, (iv) ground heat pump water–water (v) heat pump borehole/glycol, (vi) standard boiler and (vii) solar collector as driven by renewable and non-renewable energy sources. Energy and exergy analyses are conducted to assess their performances and compare them through energy and exergy efficiencies and sustainability index. Energy and exergy flows are studied and illustrated accordingly. Also, the energetic and exergetic renewability ratios are employed here along with sustainability index. The results show that overall exergy efficiencies of heating systems are found to be 2.8%, 5.5%, 6.0%, 6.4%, 6.1%, 5.4% and 25.3%, while the sustainability index values for the seven cases considered are calculated to be 1.029, 1.058, 1.063, 1.069, 1.065, 1.057 and 1.338 for options 1 through 7, respectively. So, solar collector-based heating system gives the highest efficiency and sustainability index values.