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Project
WITS UNIVERSITY EXAM VENUE GETS CESA AWARD- WINNING MAKEOVER
Contributed by the Maninga Engineering team
At the 2023 CESA Aon Engineering Excellence Awards in the category of Engineering Technology and Innovation – HVAC Building Systems Design Excellence ; Maninga Engineering received a commendation for the Test and Examination Centre : Part 1 – Flower Hall for the University of Witwatersrand .
The Wits Flower Hall is located in the south-western corner of the West Campus and is currently being used as a test and examination venue . The Flower Hall was built to house the flower displays of the WITS Agricultural Society . The building was commissioned in 1969 .
The University ’ s requirement was to free-up academic and office space for various schools in anticipation for increased enrolment of post-graduate student as per Wits 2022 Strategic Vision . Therefore , building an environmentally friendly building with a low carbon footprint without compromising end user comfort was essential .
The architects created a three-storey conversion which will initially be used as an examination venue . The mechanical solution was to accommodate dual use by the end-users while adhering to the University ’ s Urban Design Framework . The new first floor is a full floor and the second floor a partial ‘ mezzanine ’ floor . A new ‘ south ’ lobby was inserted into the first bay of the Flower Hall with staircases leading to the new floors . The existing steel glass curtain wall to the south façade was replaced with a new glazed curtain wall .
A further phase of building will see the conversion of the building for use as Engineering Research Laboratories .
Maninga Engineering , as the appointed mechanical engineers , took the task of reducing the energy consumption of the building by using unconventional methods . The objective set out was to :
• Provide thermal comfort for the occupants
• Reduce operating costs
• Ensure energy efficiency Prior to choosing a method of internal air conditioning , the cooling load had to be minimised to ensure that the equipment to be installed would not draw excessive energy . The building envelope had to be analysed and assessed . The following was done to reduce the cooling load :
• Install clear glazing to shopfronts and windows
• Install insulation to roof structure
• Separate the circulation areas from the occupiable spaces
• Recess the points of window installation – ensuring sufficient shading The active chilled beams approach was chosen for implementation . The method used allows for modular partitioning . A building management system ( BMS ) controls the chilled beams . When the client decides to convert to laboratories , each group of four chilled beams has hardwired controllers , allowing each room to be at its predetermined temperature .
Active chilled beams act as a radiator cooled or heated by recirculating water from a scroll heat pump chiller . In the instance of cooling , the warm air would rise to the chilled beam and the cold air would flow down to the occupants ; the water flow into the chilled beam is automatic and dependent on the amount of cooling required . The fresh air required in the space is distributed to the chilled beams through duct work , from a central air handling unit .
The air handling unit ( AHU ) not only serves to provide fresh air but also aids in humidity control . The chilled beam has a coil in which the heat transfer is conducted . The temperature control had to be carefully considered and catered for , so the air does not reach its dew point .
The chilled beam method is new to the continent and is in its early adoption phase . There are few installations noted in South Africa and Botswana . The Flower Hall installation is the biggest installation in Africa , with 138 active chilled beams installed in one space .
This solution is unique in that it is the largest of its kind to be installed in South Africa . It is automated and can adjust itself depending on the amount of cooling required .
The University ’ s objective was to ensure that the solution observes the health and safety of the occupants in the building . The success will be measured by the level of comfort , making the environment conducive to end-users .
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RACA Journal I February 2024 www . refrigerationandaircon . co . za