Project
Being a retrofit project , care was taken not to interfere with the existing high rise racking systems . To this end , jet nozzle diffusers were used on the ducts for distribution of air internally .
The air conditioning load is covered by three of the units , while the fourth unit offers redundancy . In normal operation , all four units operate continuously , 24 / 7 . Each AHU provides 102kWs of cooling and 31kWs re-heat capacity .
The systems are fully monitored and controlled via a Siemens building management system ( BMS ).
DIFFICULTY IN MEETING DESIGN SPECIFICATION AND SOLUTIONS Durban ’ s sub-tropical coastal climate means that RH is often extremely high , especially in the summer months . The challenge was in keeping the internal space below 55 % RH . This meant keeping infiltration under control as well as dehumidifying the internal air .
To manage infiltration , the entire volume of the space received outside air at 0.5 air changes per hour ( ACH ). This may
All image credits : © Parsons and Lumsden Consulting Engineers
One of the vertical supply air ducts with jet nozzle diffusers .
Air distribution was tricky with high rise storage racking systems .
The jet nozzle diffusers ensure good throws in a large volume room .
The air conditioning design : ground floor and sections .
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RACA Journal I September 2022 www . refrigerationandaircon . co . za