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

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.

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