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

- 43 -Table 5.1: Simulation inputs valuesData Value Unit SourceMetabolic Rate 0.9 Met Ashrae comfort toolOccupancy 0.1 People/m 2 NZS:4243Plug Load (Office Equipment) 8 W/m 2 NZS:4243Heating set point 22 Celsius E CubeNatural ventilation 24 Celsius E CubeCooling set point 26 Celsius E CubeMin. fresh air 8 l/s - person NZS:1330Lifts 4 kWh/m 2 NZGBCInfiltration 0.25 ACH* NZGBCDHW 4 kWh/m 2 NZGBCLighting 400 Lux AS/NZS 1680.1:2006Lighting power density 13.6 W/m 2 DesignBuilderDuring the design process, changes to improve performance were mostly related to variationof thermal mass and the improvement of the thermal envelope and for example by addinginsulation to the roof slab.5.2.2 Floor Areas for SimulationThe analysis of the results of this research used the net usable area. The ventilation systemoccupies a large area of space within the building; the large vertical void areas used aschimneys connected to a plant room on the roof were taken out of the gross floor area for thecalculation of the net usable area.Table 5.2 shows the initial gross floor area (calculated inside the envelope walls), thensegregated in floor area allocated to the ventilation chimneys and plant room, offices andcorridors floor area. Finally, Table 5.2 shows the net usable area which was calculated addingthe office floor area plus corridors floor area.Table 5.2: Calculation of the Net Usable Area for the analysis of resultsGross floor area 4,247 m 2Chimneys and plant room 711 m 2Offices 2,745 m 2Corridors 792 m 2Net usable area (Offices + Corridors): 3,536 m 2Initially, the net usable area was used for the calculation of the operating energy consumptionintensity per square metre. Subsequently, in order to have a single result for life-cycle energyconsumption per square metre, the initial and recurrent embodied energy were subdividedalso for net usable area. All results with reference to the intensity of energy per square meterare presented in net usable area.