18 May 2017
In Switzerland a current definition of nearly Zero Energy Buildings (nZEB) is the MINERGIE-A® label, which also includes non-residential buildings since 2014. A two-year field monitoring has been conducted in the first nZEB with office use in canton Zurich to gather experience with labelling of office buildings, approve the system design/nZEB-balance, investigate demand response options and identify optimisation potentials.
The core components of the “all electric building” are the PV-system and the ground-source heat pump. The floor heating is also used for ground-coupled free-cooling in summer. A direct electric heating is installed for legionella protection and an accompanying pipe heating for DHW comfort. Extensive monitoring equipment enables to eval-uate key characteristics of the system performance.
The nZEB-balance has been reached in the first year from May 2014 to April 2015 with a surplus of 8.6 kWh/(m2·a), which has been increased to 15.0 kWh/(m2·a) in the second year by reduction of the direct electric heating consumption by 58%. The overall seasonal performance factor of the heat pump was increased from 4.2 to 4.5. Regarding demand response capabilities, the self-consumption of the on-site PV-electricity is around 40%, which is higher than in residential buildings with 15-25% due to better load match with office use.
Detailed monitoring results of two entire years confirm that nZEB can also be reached in office buildings by state-of-the-art highly efficient heat pump and building envelope technologies in Switzerland. Moreover, good demand response can be further increased by load shifting with heat pumps.