Case study of increasing photovoltaic energy solar fraction in a conventional office building in northern latitudes
Department of Energy Engineering, Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, EE51014, Tartu, Estonia; *Correspondence: email@example.com
Current trends in planning office buildings are moving towards reducing primary energy consumption for heating, hot water heating and cooling. Availability of the solar energy resource and the low temperatures in northern latitudes from early spring until autumn provide the possibility to use photovoltaic (PV) energy for heating, cooling and other energy needs. This article calculates the heating, cooling, hot water and electricity demand of an office building with a glass facade of 65% of the total wall area. The calculated annual total energy consumption is 120 kWh m-2. To reduce the heat and electricity consumption from district heating and the power network, PV modules are integrated into the roof and facade and the solar fractions of the PV energy of the four energy loads (heating, cooling, hot water, and electricity) are found. Optimization of the PV module tilt angles on the facade and roof results in the maximum solar fraction for cooling, heating, preparing hot water, and electricity consumption, 98.4%, 32.1%, 71.7%, and 51.6% respectively. For total load, the calculated maximum solar fraction is 49.8%.