AHI Carrier has announced a R600 000 sponsorship for the Zeitz Museum of Contemporary Art Africa (MOCAA) at the V&A Waterfront in Cape Town. MechChem Africa talks to Jaco Smal, the company’s Cape Town-based commercial sales director.
V&A Waterfront’s Silo District is built around the historic Grain Silo complex, once the tallest structures on the city’s skyline, and central to the economy of the harbour and the Western Province.
Nearing completion, the V&A Waterfront’s Silo District is already home to a six-star Green Star SA office space, more than 30 luxury apartments in Silos 1 and 2 respectively; and an additional residential development, a Virgin Active Classic Health Club, and a super-modern office building in Silos 3 to 5.
Currently being finalised, the state-of-the-art Zeitz MOCAA in the Grain Silo complex is a new public not-for-profit cultural institution, the first major art museum in Africa aspiring to be an internationally-renowned destination for lovers of Art from Africa and the Diaspora.
The total investment in the Silo District development at the V&A Waterfront by shareholders Growthpoint and the Government Employee Pension Fund, which is managed by the Public Investment Corporation (PIC), is over R2.5-billion.
Approximately 2 500 people are expected to work at the Silo District, with the original economic impact study suggesting that the expected nominal contribution to GDP from future developments will be over R29-billion by 2023.
A district-wide HVAC solution
“Carrier’s involvement with the Silo District began with a request from David Lombard of Lombard Consulting Engineers, who asked several service providers to procure the best equipment available for a centralised Waterfront Silo District cooling and heating plant room,” says AHI Carrier’s Jaco Smal. “The idea was to supply on-demand chilled and heated water from a central plant room to air-handling units distributed throughout Silos 3 to 6.
“At the heart of the system is the use of seawater instead of evaporative cooling towers to reject the waste heat,” Smal explains. “We circulate naturally-cool seawater through heat exchangers so that the system does not require cooling towers to reject heat into the atmosphere. As well as the better efficiencies associated with water cooling, this avoids having to consume water through evaporation,” he explains. “The entire Silo District is built on green principles and energy efficiency. The directive was to achieve the best possible energy efficiency for every tenant,” he adds.
Two Carrier AquaEdge 23XRV chillers were chosen to meet most of the demand from the four connected Silo developments. “These state-of-the-art variable speed screw chillers are able to operate off condensed water at a temperature as low as 13 °C, which makes them ideal for chilling from the cold-water temperatures associated with the seawater. We usually run the units at inlet temperatures of 18 °C to 19 °C, but the chillers have to be able to cope when the seawater drops to lower temperatures,” Smal tells MechChem Africa.
In addition, a further two Carrier AquaForce 30XW-V water-cooled variable speed screw chillers are used for both cooling and heating. These have very high part-load efficiencies, allowing for exact matching of the cooling capacity to the load.
“Most importantly, these machines are all extremely robust and reliable. In general, highly-efficient machines are often seen as delicate and unreliable. But these are all designed for reliability, for which Carrier is renowned. Since their initial introduction in the US in 2005, we have never had a compressor failure,” Smal reveals.
As for the efficiency of the Silo District plant room? “Typically, in peak summer, we generate chilled water at 7.0 °C, which gives us a COP of between 10.54 and 13.28. This means that the two AquaEdge 23XRV chillers can each produce 1 500 kW of cooling from between 113 and 142 kW.
“For cooling during intermediate months, when the ambient temperature is closer to the set point, we can raise the chilled water temperature to 10 °C, which gives us a COP of 12.7 at 100% capacity, rising to 15.85 at 40%,” Smal tells MechChem Africa, adding that, “on machines of this size, this efficiency is as good as it gets.”
The Zeitz MOCAA sponsorship
The Silo District developments are focused around Zeitz MOCAA, which sits at the heart of this district. Surrounding the museums will be a new central pedestrian plaza, Silo Square, a gathering place for locals and international visitors.