Architect and Builder Magazine South Africa March/April 2015

and lockers. Dedicated routes for cyclists provided in basements • Preferential bays for hybrid cars, motorcycles • Performance glazing used to reduce load on HVAC system • Power factor correction is installed at medium voltage to ensure that the maximum demand of the site is equal to the actual energy used • No incandescent lamps are used. • Low voltage lamps are kept to a minimum by using alternative technologies like LED lamps, compact fluorescent and natural daylight • All light fixtures are equipped with electronic ballasts • Light fittings in the office environment are equipped with T5 Technology • Occupancy sensors are used in the office space to ensure that the electrical lighting load is kept to a minimum • In addition, the office lights are switched off after hours by the building management system • The architectural designs incorporate the use of natural daylight in the offices, atrium and entrances • External light fittings are switched via photocell • The HVAC system incorporates a centrally chilled water system for maximum energy efficiency • The building is designed to be a notional building as described in SANS 204 and will yield better efficiencies as described in the Code • The HVAC design also incorporates a full economy cycle thereby using external fresh air during optimal external conditions Acacia House HVAC HVAC is a decentralised variable air volume (VAV) system serving the office building and ground floor branch, restaurant, Welcome Centre and other special areas. A high-efficiency water cooled chiller plant supplies chilled water at approximately 8ºC to the various air handling units on the office floors. Condenser water from the chiller is distributed to dry coolers used for heat rejection. The chilled water plant is located in a double volume plant on basement 3 and the dry coolers are located in a triple volume air cooled plant room (basement 2, 3 and 4). The VAV air handling units supply filtered and conditioned air at a varying temperature to the office space. The supply air temperature set-point will automatically be reset according to the zone’s cooling requirements thus maintaining better air quality and reducing the terminal reheat load and energy consumption. The units are not supplied with an economy cycle due to high humidity conditions in Umhlanga. The supply air is distributed throughout the airconditioned areas by means of externally insulated galvanised sheet metal ducting. Supply air is introduced into the airconditioned space by means of ceiling mounted VAV swirl diffusers. The diffusers consist of a motorised damper that controls the amount of conditioned air supplied and electrical heater element. The indoor air temperature is controlled through a wall-mounted set-point adjuster that allows occupants to adjust to the desired temperature set-point. 45

Architect and Builder Magazine South Africa March/April 2015 | Page 45