CIS Nordhavn is a new school building for Copenhagen International School, which is located on a prominent site in Copenhagen’s new Nordhavn district. 12,000 solar panels cover nearly all façades of the school building, each individually angled to create an overall good architecture. And the large building integrated PV system ( BIPV ), will supply more than half of the school’s annual electricity consumption. It has the largest BIPV installation in Europe with approximately 6000 m2 equal to 720 kWp photovoltaic (PV) in total. This project is in connection to the Danish ForskVE/EUDP project, LowCost Active House BIPV project being labelled according to the international Active House standard.
The CO2 concentration level is ≤ 350 ppm above outdoor CO2 concentration in most of the rooms. On the Active House radar the result is equal to a satisfying level 1. The maximum temperature level is calculated to level 2 in the Active House radar which means it is in the range between 21 and 26 degree Celsius during the year. The reason for the good results are due to decentralized ventilation systems, which provides a high air exchange.
The lighting quality is also good based on a combination of LED lighting and access to daylight. The windows area has an average ratio of around 32 % of windows area over floor area, which ensures a very good daylight factor inside the rooms of 5,4%.
There is also no emissions from heating and cooling systems since the school uses district heating and district cooling.
Total energy demand is 30,1 kWh/m2 resulted from heating and electricity demand by 16,7 and 13,4 kWh/m2 respectively.
The actual heating use is 10.4 kWh/m2 and 6.3 kWh/m2 for room heating and domestic hot water (DWH), also based in a very good insulation of the building envelope with values of 0.74; 0.1; 0.11 and 0.12 W/m2 C, for the windows, external walls, roof and ground floor respectively. The building is connected to the local district heating network. At present district heating is the largest heating system supplier in Denmark covering 63% of Danish households.
For ventilation an electricity use (SEL value) of 1.3 kJ/m3 was calculated, with a heat recovery efficiency of 82 % as an average. Also a mechanical cooling system was installed.
The PV modules were produced by SolarLab as 60 W green chromatic coated hardened glass panels of 700 X 716 mm , with 16 monocrystalline PV cells (6”) and by pass diode, where 8 panels is coupled to a micro inverter which is easy accessible from the loft.
The panels were wind tunnel tested prior to use to avoid noise. Furthermore, the panels have different tilts with 4 inclination randomly chosen.
The contribution from 720 kWp PV panels on all facades (approximately 6000 m2) is 10.7 kWh/m2, which can be compared to the yearly electricity use for operation: lighting, fans, pumps and cooling of 7.0; 5.3; 0.2 and 0.9 respectively.
The Danish Be15 calculation shows an overall final energy use of 15 kWh/m2 per year. Compared to low energy class 2020 in Denmark, which demands a level of max. 25 kWh/m2 per year for a school, it is a very satisfying result.
It is important to point out, that the active house tool calculation takes in consideration the renewable energy production part from the grid, unlike the Danish energy frame calculation.
Approximately 58 % of the Central district heating /cooling in Copenhagen is produced by green energy sources. Moreover, renewable resources produce also 50 % of the Danish grid electricity. In total, taking in consideration the renewable part of electricity and district heating from the grid, 72 % of the energy demand is supplied by renewable energy sources, which is equal to 21,8 kWh/m2.
As a result, the primary energy of the building is only 6.6 kWh/m2, equal to a level 2,4 in the Active House radar.
CIS is a good example of the Prosumer building of the future with BIPV on all facades and actually with a good architecture due to the special PV panels and architectural design. With about 39 % of the total electricity use covered by the PV modules production, CIS is a good example of and almost zero energy building, which also has a good score in the Active House label.
Author: Peder Vejsig Pedersen & Miriam Sanchez Mayoral, Kuben Management