Projects and thus required an further three storeys to be included . So , this then became a 12-storey building – excluding the ground floor . The entire redevelopment also made use of the original building ’ s foundations .
As a mixed-use or multi-purpose building , the conversion changed the ground floor into a restaurant and hotel lobby , and includes a few small retail shops . The first to fourth floors have been set up to accommodate standard office-space tenants , the fifth to tenth floors are a luxury hotel , and finally , the eleventh and twelfth floors are high-end luxury offices .
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THE HVAC SYSTEM , DESIGN AND ENERGY SUPPLY In considering an appropriate system for this project , VMG Consultants was appointed to co-ordinate the solution and technology for the building , making sure that what was to be provided matched the heat loads and cooling demands . They worked closely with HVAC contractor Tempkor , and power solution specialist Blackdot Energy , who were responsible for the proposals and installation of the tri- , and installed cogeneration electrical system for the building .
VMG needed to look at the type of HVAC system best suited given the various criteria and limitations , and decided on the Mitsubishi Electric variable refrigerant flow ( VRF ) system throughout the building . Configurations were then split across the different types of VRF system that Mitsubishi Electric offer .
The VRF market has grown exponentially over the last decades , not only in South Africa but globally . Mitsubishi Electric has also always been seen as a ‘ VRF company ’ and are known for their huge amounts of research and development into this technology over the last 20- plus years , particularly the 2-pipe heat recovery system . What many people may not know is that this particular 2-pipe technology is owned by Mitsubishi Electric through a registered trademark as the only VRF system using 2 pipes for simultaneous heating and cooling . All other brands use a 3-pipe technology .
Mitsubishi Electric launched their hybrid VRF technology first in Japan and then it moved to Germany where it spent a further two years being perfected and was then opened up to the European market . It was then released in South Africa in 2019 . Currently the Mitsubishi Electric HVRF system is compatible with either R410A or R32 .
The Bank ’ s ground floor , lower office space and premium offices all incorporate a standard heat recovery VRF system , while the hotel adopted the continent ’ s first new chilled / hot water hybrid VRF system . This system combines the refrigerant HVRF technology with chilled water . This feature is also the flagship item on the project as the first in Africa with the six-floor hotel space benefitting with the newest technology in the VRF range .
The office spaces have been fitted with a mix of cassette and ducted hideaways because these allow far more flexibility in office-partitioning or layout changes . Installing diffusers then allows you to move around more easily , whereas the cassette solution is purpose-fit for particular offices . Taking this into account VMG worked towards the solution ratio that offered the most flexibility for any future changes .
The hybrid solution was not implemented for the office spaces and ground floor because these areas didn ’ t pose significant risk to the occupants – the areas have set times of occupancy and if any refrigerant leaks occur , there is much more open space and ventilation means than in the hotel rooms . Any leaks would be picked up through an error code on the system in any event .
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1 . The energy management central controllers located on the ground floor .
2 . The smoke extraction installed in the basement parking .
3 . Accommodating a lower office level tenant requirement , various ducted units are being installed .
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www . hvacronline . co . za RACA Journal I February 2021 31