Projects
One of four
basement
ventilation shafts.
Reduction of energy consumption contributes to reduction of
greenhouse gas and other emissions. The energy efficiency
strategy incorporates:
• Performance glazing – allowing optimal light to
penetrate without the solar heat gain,
• Effective thermal insulation throughout the office area,
• Efficient building systems for reduced energy
consumption - HVAC, lighting, domestic hot water
heating, lifts and escalators,
• Management and monitoring of building services
through a Building Management System (BMS),
• Efficient lighting - Average lux levels of approximately
400Lux and lighting power densities of less than 1.5W/
m² per 100Lux for office usable area,
• Appropriate lighting zoning and occupancy sensors to
ensure lights are switched off in unoccupied spaces,
• Heat pumps for domestic hot water generation, and
• Electricity generation from renewable source (PVs).
“The expected energy consumption is 148.1kWh/m²/year, while
expected annual emissions are 76.5kgCO 2 /m²/year,” he says.
INDOOR ENVIRONMENTAL QUALITY
Various aspects have been carefully considered in order to
achieve optimal Indoor Environment Quality (IEQ) for the
development. The enhanced indoor environmental quality
strategy looks at air quality, smoking, lighting, temperature,
noise, daylight and glare.
www.hvacronline.co.za
“Outside/Return Air Filtration is at 70% Arrestance. This is
a typical filter specification for this type of building. Dust
problems often revolve around housekeeping; dust and
air conditioning borne dust at this level of filtration usually
results in acceptable dust counts in terms of environmental
standards,” Huddle explains.
AIR QUALITY
•
•
•
Energy efficient air-conditioning system proving fresh
air at rates of 12.5l/s/person for 100% of the Usable
Area giving a 66% improvement on SANS 10400-
O:2011,
Low/no volatile organic compounds (VOCs) interior
finishes,
Exhaust risers to extract pollutants of copy areas.
Outside air is provided to the 144 Oxford building at rates
much greater than the requirements of SANS 10400-O,
namely greater than 12.5 ℓ/s/person for 98% of Usable Area.
It is recommended that the tenants keep to the occupancy
rates to what the building was designed for, should the
occupancy rate increase the air conditioning system can be
upgraded accordingly. The air-cooled chilled water system
is made up of four chillers each supplying 800kW of cooling
throughout the entire building. “We’ve got 17 air handling
units that serve thermal zones in the building for example,
there is one AHU serving the entire southern façade. It’s all
thermally zoned,” he says.
RACA Journal I May 2020
51