1. NeZeR Design Competition Sweden Maria Ahlm, IVL Swedish Environmental Research Institute Sara Magnusson, student, winner of 1st price Alexander Skogfeldt, student, winner of 3rd price
Sustainable Built Environment conference –SBE 16
Tallinn/Helsinki, 5-7 October 2016

2. The Swedish example building
Apartment block, multifamily building with 22 apartments, 3 floors, 1691 m2
Constructed in
Last renovation in 2008 (change of HVAC system)
Owned by Stockholmshem (largest property owner in Stockholm)
Cultural important buildings
Energy consumption (kWh/m2 Atemp)
Space heating and DHW
150 (appr 120 heat + 30 DHW)
Property electricity 3
Sweden

3. Renovation concept
Principles used for renovation: a mix of different measures
Ambition – energy performance before and after renovation:
Energy consumption before renovation: 150 kWh/m2 Atemp
Energy consumption after renovation: 41 kWh/m2 Atemp (simulated, probably quite substantial overestimation of energy efficiency improvement)
Building envelope improvements: insulation, new windows
Changes in HVAC installation: Ventilation with heat recovery
Renewable energy technologies: geothermal energy (through heat pump)
Sweden

4. Proposed technical solutions
Original building
After NZEBR
Basement floor
Thin insulation
15 cm added insulation
Roof
10 cm mineral wool insulation
50 cm mineral wool insulation
Windows and doors
U value approximately 3 W/(m2,K)
U value 1.4 W/(m2,K)
HVAC
Mechanical ventilation without heat recovery
Ventilation with heat recovery
RES
District heating (partly recycled and renewable energy)
Geothermal heat pump (renewable energy contribution from geothermal energy and part of the electricity)
(Solar heating and solar PVs)
Other
Lowered temperature especially in the basement (to 18 C) but also in the apartments (to 21C)
Sweden

5. Environmental aspects – Materials selected
Roof insulation from mineral wool (recycled glass)
Substantially lowered energy consumption  lower emissions from energy use (10-14 tCO2e/year)
Some of the concepts also included other indirect measures improving environmental performance, such as bicycle supporting measures
For comparison
Sweden

6. User aspects
Ventilation with heat recovery gives better indoor comfort
Indoor climate improvement by controled ventilation, better windows (reduced draft from windows)
The proposed measures require evacuation of the tenants
Some of the concepts included indirect social measures, e.g. local cultivation of vegetables
Sweden

7. Aesthetical Aspects
Cultural classified building  very strict regulations, facades must not change appearance
One of the concepts proposed new entrence halls (air locks) to reduce the draft into the stairwell. Interesting option to reduce energy use without changing the appearance to a great extent
Sweden

8. Market appeal High replicability of measures Well-known measures
Chosen package solution has relatively low life cycle cost
Mainstream solutions  low technical risk
The winning concept with geothermal heat pump will require more maintenance compared to the original heating system (district heating)
Sweden

9. Strengths and weaknesses
Strong points of renovation concept:
Replicability
Well-known technologies
Improved indoor climate
Weaknesses / aspects to be improved:
No revolutionary solutions
No/low primary energy savings when converting from district heating to heat pump
Sweden