Solar energy systems potential for nearly net zero energy residential buildings

Solar energy systems are currently the most widely installed renewable energy systems in the building sector in an effort to reduce the energy consumption of buildings. This paper investigates solar potential regarding photovoltaic and solar thermal utilization in typical residential buildings in order to identify their impact towards nearly Net Zero Energy Buildings (NZEB). Different options regarding the installed capacity of photovoltaics and solar combi systems in various locations and climatic conditions are evaluated from a technical as well as from an economic point of view. The results indicate that in all cases, photovoltaics are able to cover the annual electricity demand of a residential building with a payback period of less than 7 years. In the case of solar combi systems, payback period ranges between 5.5 and 6.5 years when compared with a conventional fuel oil heating boiler and 9 years when compared with a natural gas boiler, providing at least 50% of the total heating demand of the buildings. In total, solar energy systems are able to cover at least 76% of the primary energy demand of residential buildings proving that they are a viable solution towards NZEB.