Environmental Impacts of Multi-Storey Buildings Using Different ...
Share Embed Flag
Download ePaper

Environmental Impacts of Multi-Storey Buildings Using Different ...

Environmental Impacts of Multi-Storey Buildings Using Different ... Environmental Impacts of Multi-Storey Buildings Using Different ...

scnz.org
10.07.2015 Views

- 44 -5.2.3 Buildings’ Thermal Envelope DescriptionsTable 5.3 shows the different construction of the office area envelope walls, including wallthickness, R/values (heat loss) and the percentage of the section of each wall configurationtype within the total wall for each of the walls involved in the envelope of the main body ofoffices, for each of the Concrete, Steel, Timber and TimberPlus buildings. This informationis of importance because only the office areas use HVAC (mixed with natural ventilation), sothere is significant energy consumption required to keep a comfortable range of temperatureinside those areas, with heat losses through walls having a particularly large impact.As seen in Table 5.3, a significant difference between the Concrete building (with highthermal mass) and the three other buildings (with lower thermal mass) - Steel, Timber andTimberPlus - is that the Concrete building has a much thicker wall in the east and westfacades (Thermomass) than the east or west facades of the Steel, Timber or TimberPlusbuildings. Despite this much greater thickness, the R/Values are lower for the Concretebuilding than for the Steel, Timber and TimberPlus buildings. The wall description in all fourbuildings is segregated into cavity walls and structural walls.All light weight envelope walls in the Steel, Timber and TimberPlus buildings, including thesouth façade internal wall of the Concrete building, have 90 mm thick fibre-glass insulation.There was no variation in the thickness of insulation between any buildings, so the finalR/value differences between light weight walls is due to the influence of different linings,claddings and air cavity thicknesses. The TimberPlus building normally has higher R/valuesthan the Timber building, due to timber external claddings and interior linings.Table 5.3 is a summary of detailed wall specifications. Total R/Values were calculated by theDesignBuilder software used for simulations.When looking at light weight walls in any of the four buildings, the cavity is the section of thewall that contains insulation between the internal linings and the external air cavity under thecladding, and the structure is the section of the wall that contains the studs and nogs(blocking) all added together, acting as a thermal bridge. In the case of the Steel building, thepart of the wall structure acting as a thermal bridge is only the web of the cold-rolled steelchannel used as studs. On the other hand, in a timber frame wall, the area acting as a thermalbridge is the complete timber stud width. Nevertheless, thermal conductivity is much higherin steel (45.3 W/mK) than in timber (0.11 W/mK) so the incidence of the small portion ofsteel in a steel framed wall is as significant as a much larger portion of wood in a timberframed wall (ASHRAE American Society of Heating, 2005).Because of the high thermal conductivity of steel, the main structural system of the steelbuilding was left inside the offices and not within envelope walls so it doesn’t drasticallyincrease the heat losses. On the other hand, in the Concrete, Timber and TimberPlusbuildings, the structural systems are rather similar and the shear walls are part of the structuralsystem. This means that in the east and west facades, the structural walls are part of theenvelope walls, somewhat decreasing the total R/Value. In the Concrete building, there is alayer of extruded polystyrene in the core of the structural walls but in the Timber andTimberPlus buildings no extra insulation has been added to the shear walls. The influence ofstructural components on the thermal envelope is the main reason why all four buildingscannot have exactly the same R/Value, even when the same insulation is used.

- 45 -Table 5.3: Areas of office envelope walls including thickness and R/values for the Concrete, Steel, Timberand TimberPlus buildings.Wall construction Thicknees R/Value % in wall1 Concrete buildingEast and West facades: Concrete / Thermomass 310 mm 2.02 100 %South facades: Concrete / Thermomass 310 mm 2.02 22 %Light weight envelope wall / cavity 137 mm 2.68 73 %Light weight envelope wall / structure 137 mm 1.50 6%North Façade: Glassing Courtain wall 50 mm 0.56 100 %Roof: Concrete / roof Floor (ceiling incl) 814.5 mm 2.59 100 %Internal floor: Concrete / Internal Floor (ceiling incl) 814.5 mm 0.79 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %2 Steel BuildingEast and West facades: Light weight envelope wall / cavity 138.5 mm 2.65 97 %Light weight envelope wall / structure 138.5 mm 0.23 3%South facades: Light weight, south wall / cavity 147 mm 2.68 97 %Light weight, south wall / structure 147 mm 0.25 3%North Façade: Glassing Courtain wall 25 mm 0.56 100 %Roof: Steel / Roof slab (ceiling incl) 814.5 mm 2.47 100 %Internal floor: Steel / Internal floor (ceiling incl) 814.5 mm 0.67 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %3 Timber BuildingEast / West / south facades: LVL Shear Wall 286 mm 2.06 72 %Light weight envelope wall / cavity 137 mm 2.68 27 %Light weight envelope wall / structure 135 mm 1.50 1%South facades: Light weight envelope wall / cavity 137 mm 2.68 90 %Light weight envelope wall / structure 135 mm 1.50 10 %North Façade: Glassing Courtain wall 25 mm 0.56 100 %Roof: Timber / Roof slab (ceiling incl) 864.5 mm 2.58 100 %Internal floor: Timber / Internal Floor (ceiling incl) 814.5 mm 0.78 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %4 Timber Plus BuildingEast and West facades: LVL Shear Wall 331 mm 2.42 72 %Light weight envelope wall / cavity 144 mm 2.81 27 %Light weight envelope wall / structure 144 mm 1.23 1%South facades: Chimney, south wall / cavity 149 mm 2.84 90 %Chimney, south wall / structure 149 mm 1.23 10 %North Façade: Light weight envelope wall 144 mm 2.84 30 %Glassing Courtain wall 25 mm 0.56 70 %Roof: Timber / Roof slab 864 mm 2.58 100 %Internal floor: Timber / Internal Floor 814.5 mm 0.78 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %5.2.4 HVACFor all four buildings, the HVAC system operates when the inside temperature is below 22 °Cand above 26°C. Between 22 °C and 26°C the buildings all work under a natural ventilationmode with no heating or cooling. The building designs include two internal ventilationchimneys that under natural ventilation mode and are set in simulation to exhaust the aircoming into the buildings through opening windows in the curtain wall of the north façade.

- 45 -Table 5.3: Areas <strong>of</strong> <strong>of</strong>fice envelope walls including thickness and R/values for the Concrete, Steel, Timberand TimberPlus buildings.Wall construction Thicknees R/Value % in wall1 Concrete buildingEast and West facades: Concrete / Thermomass 310 mm 2.02 100 %South facades: Concrete / Thermomass 310 mm 2.02 22 %Light weight envelope wall / cavity 137 mm 2.68 73 %Light weight envelope wall / structure 137 mm 1.50 6%North Façade: Glassing Courtain wall 50 mm 0.56 100 %Ro<strong>of</strong>: Concrete / ro<strong>of</strong> Floor (ceiling incl) 814.5 mm 2.59 100 %Internal floor: Concrete / Internal Floor (ceiling incl) 814.5 mm 0.79 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %2 Steel BuildingEast and West facades: Light weight envelope wall / cavity 138.5 mm 2.65 97 %Light weight envelope wall / structure 138.5 mm 0.23 3%South facades: Light weight, south wall / cavity 147 mm 2.68 97 %Light weight, south wall / structure 147 mm 0.25 3%North Façade: Glassing Courtain wall 25 mm 0.56 100 %Ro<strong>of</strong>: Steel / Ro<strong>of</strong> slab (ceiling incl) 814.5 mm 2.47 100 %Internal floor: Steel / Internal floor (ceiling incl) 814.5 mm 0.67 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %3 Timber BuildingEast / West / south facades: LVL Shear Wall 286 mm 2.06 72 %Light weight envelope wall / cavity 137 mm 2.68 27 %Light weight envelope wall / structure 135 mm 1.50 1%South facades: Light weight envelope wall / cavity 137 mm 2.68 90 %Light weight envelope wall / structure 135 mm 1.50 10 %North Façade: Glassing Courtain wall 25 mm 0.56 100 %Ro<strong>of</strong>: Timber / Ro<strong>of</strong> slab (ceiling incl) 864.5 mm 2.58 100 %Internal floor: Timber / Internal Floor (ceiling incl) 814.5 mm 0.78 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %4 Timber Plus BuildingEast and West facades: LVL Shear Wall 331 mm 2.42 72 %Light weight envelope wall / cavity 144 mm 2.81 27 %Light weight envelope wall / structure 144 mm 1.23 1%South facades: Chimney, south wall / cavity 149 mm 2.84 90 %Chimney, south wall / structure 149 mm 1.23 10 %North Façade: Light weight envelope wall 144 mm 2.84 30 %Glassing Courtain wall 25 mm 0.56 70 %Ro<strong>of</strong>: Timber / Ro<strong>of</strong> slab 864 mm 2.58 100 %Internal floor: Timber / Internal Floor 814.5 mm 0.78 100 %Ground floor: Concrete / Ground Floor 1327 mm 2.80 100 %5.2.4 HVACFor all four buildings, the HVAC system operates when the inside temperature is below 22 °Cand above 26°C. Between 22 °C and 26°C the buildings all work under a natural ventilationmode with no heating or cooling. The building designs include two internal ventilationchimneys that under natural ventilation mode and are set in simulation to exhaust the aircoming into the buildings through opening windows in the curtain wall <strong>of</strong> the north façade.

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!