BUILDING RETROFITTING Case study Sustainable Design
Renovation Residential Building Kapfenberg 1961 in Austria
Sustainable Design
General Information Project Location
Project type
Time schedule
Johann-Böhmstraße 3436 in Kapfenberg (Austria)
Typical Residential Building, Post-war Residential Building.
Built: 1960-1961 Renovated: March 2012- Jan 2014
Surfaces Areas And Use
Construction Costs
Total Ground Floor Area (GFA): 2,845 m2 Total Volume: 8,538 m2 4-Storey with apartments varying from 59 to 88 m2 (32 apartments in total)
• • •
Building Cost: Ca.1.5 €/ M2 (Without PV System) PV System Cost: Ca. 2.5 €/ Kwp Total Renovation Costs: 4.3 M €
Original Design
Made of prefabricated sandwich concrete walls without insulation.
Ventilation source was only windows. This caused very high heating and operating costs for the residents.
Sustainable Design
Various heating systems: central gas heating, electric and coal furnaces, electric night storage heaters, etc.
Sustainable Design
Finished Building Back Side
Finished Building Front Side
Energy Concept
80% Energy Demand Reduction: •
Reduction of transmission, infiltration and ventilation loss in the building envelope.
80% Ratio Of Renewable Energy Sources: Using Solar Thermal and PV Systems.
80% Reduction Of Co2 Emissions. Intelligent integration of existing energy sources: •
Connection to an existing local district heating network and PV system integration with the electricity grid.
Sustainable Design
•
Sustainable Design
Existing building baseline
Minimum requirements Austrian building code Reduction of 47%
Improvement of u-values Reduction of 55%
Scenario 3+ mechanical ventilation + heat recoveryReduction of 62%
Scenario 4+ PV modules + solar collectors Reduction of 85% (target)
Renovation scenarios
Before
Before & After
Implemented Renovation Solutions
https://www.buildup.eu/en/practices/cases/plusenergy-building-renovation-prefabricated-thermal-facade-elements-kapfenberg
Sustainable Design
New façade (prefabricated active and passive elements) New windows New roof (flat roof instead of pitched roof) New building systems • Local district heating • Solar thermal panels for domestic hot water (DHW) and heating • Mechanical ventilation system with heat recovery and photovoltaic panels
After
Before
Before & After
Sustainable Design
After
Envelope performance Tested U-value averages:
Element
Area m2
U-value before renovation W/m2.K
U-value after renovation W/m2.K
Façade
1.463
0,87
<0,17
Ceiling
711
0,39
<0,30
Windows, doors
349
2,50
<0,90
Roof
711
0,74
<0,10
Renovation Process
Sustainable Design
Sustainable Design
Renovation Process
Building Envelope Improvement
Sustainable Design
Walls • • • • • • • • • •
Pre-fabricated wooden facade elements. U-value: 0.12 W/m2K. Cement fiber panel 0.8 cm. Air space 5.0 cm. Cross laminated timber 5.9 cm. Wood construction with mineral wool insulation 20.0 cm. Mineral wool 6.0 cm. Vapor barrier Exterior plaster existing wall 2.5 cm. Existing wall: sandwich concrete elements 20.0 cm. Interior plaster 2.0 cm.
Building Envelope Improvement Windows • • •
U-values: • Uglass = 0.70 W/m2k. • Uframe = 1.17 W/m2k. • Uwindow = 0.97 W/m2k. • G-value = 0.60.
Sustainable Design
Windows integrated in the prefabricated facade modules Windows with high thermal quality External shading device integrated in the facade module • Helps to reduce the solar gains • Avoid overheating the rooms in the warm days
Building Envelope Improvement
Basement ceiling
Sustainable Design
• • • •
Due to the low ceiling height, it was not possible to install more than 6 cm insulation The existing building has already been insulated with 6 cm insulation. The thermal insulation was renewed during the renovation The energy performance of this component was not much improved (U-value: 0.30 W/m2K).
Building Envelope Improvement
Roof Sustainable Design
• The existing old pitched roof was removed and a new flat roof was installed with 35 – 40 cm of polystyrene. • U-value: 0.10 W/m2K.
Renewable energy Renewable Energy production system, 80% of total energy use Photovoltaic (PV Panels) •
Sustainable Design
• •
550 m² (ca. 80 kWp) of PV panels located on the roof on a mounted scaffold that has the form of a wing 80 m² (ca. 12 kWp) of PV panels located on the south façade Total production of the 630 m² (92 kwp) is about 80 mwh/a
Solar Thermal System • • • •
Solar thermal system with a collector surface of 144 m² Scaffold on the south facade was mounted to • Increase the area for the solar thermal panels • Optimize the inclination of (inclination of the solar thermal panels = 72°) Annual heat production of 39.5 mwh/a Produced heat in a 7500 liter buffer storage located below solar thermal panels
شكرا
Sustainable Design
Thank you