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

- 41 -5 Operational Energy5.1 GeneralThis section presents the data setup used in the operational energy simulation process,describes the thermal envelope configuration of the four alternative building designs, providesa description of the heating, ventilation and air conditioning (HVAC) systems used, thelighting systems and the schedule for simulations.Figure 5.1 shows the floor plan used for the Concrete, Steel, Timber and TimberPlusbuildings. It also shows a transverse cross-section through the ventilation chimneys. Thefloor is subdivided into four zones; three offices and one corridor and services area on thesouth side.Figure 5.1: Plan used for energy calculations, and cross-section through the ventilation chimneys.For operational energy modelling, only the office zones have HVAC control. The corridorsand service areas only have manually opening windows, set for natural ventilation. Two largeventilation chimneys were placed in the actual Concrete design for the Biological Scienceslaboratory building, and these are retained in the four case study designs considered in thisreport. The ventilation chimneys are continuous through all floors, from ground level up tothe plant room on the roof slab. They are used for natural ventilation with automaticallycontrolled louvres set to be opened between 22°C and 26°C. When the louvres are closed, theair conditioning keeps the temperature at 26°C until 6pm.Of central importance to the design of the research covered by this report was the requirementto have all four alternative designs displaying very similar operational energy consumptionover the lifetime of the buildings. Several previous researchers have found that even whenthe energy efficiency of buildings being compared is code-compliant, the effects of theembodied energy of construction materials are difficult to discern and negligible in