By: Donovan White (Projects Writer)
Legacy Group’s newest development, Legacy Corner, is a multifunctional building consisting of hotel, residential, and retail sectors designed to attract business and leisure seekers.
Founded by Bart Dorrestein (CEO Legacy Hotels and Resorts) and the late Bruno Corte, Dorrestein lives his business partners’ luxuriant tradition by leaving a legacy of African hospitality and residential properties built and run to highest international standards. The group now offers their clientele the ultimate lifestyle experience in shopping, living, wellness and gaming, through Legacy Corner.
This facility encompasses Legacy Corner Mall, The DΛVINCI Hotel and Suites, The DΛVINCI Spa and Gym and The Marco Polo. With its black and white post modernistic interiors, the complex began its construction in September 2007 and finished in May 2010, in time for the 2010 FIFA World Cup. WSP established the HVAC design brief for this high end mixed use facility with the following outcomes:
The DΛVINCI Hotel and Suites: “Eternal fame”
The 168, contemporary styled with classical accent, DΛVINCI hotel rooms are air conditioned by means of Sinko fan coil units (FCUs) situated above the entrance lobby of each room. Air is supplied to each room from the FCUs by means of a supply air grille mounted in the entrance lobby bulkhead. Air is returned to the unit by means of a return air grille mounted below the unit. This is a typical hotel room air conditioning principle. Because noise in hotel rooms is a concern, special care was given to the selection of the unit and grilles. The selection paid fruit as noise levels in all hotel rooms were kept below 40dBA.
Public areas, boardrooms and the gym are cooled via eight Heat Pump International (HPI) chilled water air handling units (AHUs). George Arnold, WSP consulting engineer, says they used Heat Pump International because of its good delivery times, price and after sales abilities. 6°C chilled water is generated by means of two partial heat recovery Clivet chillers located on the roof.
For the 50 exclusive one, two and three bed roomed apartments, as well as four large penthouses located in the residential section, Arnold says they wanted variable refrigerant volume (VRV) technology because the system is ideal for a residential development due to the diverse nature of apartments and the occupants. Twelve LG Electronic’s MultiV Sync II systems were used and the supply of these units came in good time as LG was already supplying other materials, such as, television sets a big central water cooled air conditioning was also not an option for the residential sector as it is costly and difficult to bill tenants individually.
Service voids in the hotel area posed a challenge for duct and chilled water pipe runs. Limited void space made the installation of all services extremely difficult. Bentel Associates International (BAI) had to change the bulkheads in the hotel passages after all the services had been installed to accommodate all the services and meet the client’s needs. Since the DΛVINCI Hotel comes with a sense of grandeur, visibility of the plant room is not an option. Located on the roof, the plant posed space restrictions and Page says it was difficult to get it into workable positions, given that it houses approximately 105 solar panels, two cooling towers, two chillers and 12 condensers. Shading devices on the balconies of the penthouses aid the hiding of the plant. Skylights also help this cause while providing natural lighting to penthouses. The HVAC installation consumes roughly half the building’s electrical supply.
Legacy Corner Mall: “The city will gain beauty worthy of its name”
The first three levels of Legacy Corner is Legacy Corner Mall, the retail side of the development. All of the shops received a standard design and once the internal design was received for each store, the standard design was adapted to suit the individual internal layouts. Arnold says that there were definite interior design challenges to integrate with BAI and Stephen Falcke’s Black and White themed interior design vision. Tenants such as Art Afrique gallery, Vodacom 3G, MTN Cellular, Colours, Aldo Bru, Giovanni Uomo, The Vault, Geri Ziffereli, Manna Boutique and, Exclusive Books tend to have the same HVAC design, but high fashion stores such as 312 Couture and Moloko Fashions were more tricky. One store required a black ceiling mirror, requiring different and creative diffuser positions.
Legacy Corner Mall has a floor standing water cooled air conditioning system. Page says they looked at the build ability, sizes, flexibility, price and delivery of the eight Mitsubishi water cooled units and Evapco cooling towers when they decided on products to use. After sales was a big part of the product selection. All indoor design was done to 22.5°C.
Ventilation: “In the air and it will rise high”
The basement is ventilated by means of axial flow fans discharging to atmosphere at road level with acoustic louvers. Restaurants and kitchens make use of ultraviolet (UV) canopies. This is not a new technology, Arnold says, but it is expensive. Working in conjunction with the UV canopies are the Ecology units installed by Catervent. UV canopies and Ecology units prevent smells and smoke leaving the building. It is for this reason that these two products were carefully selected to work in conjunction with each other.
Via a common riser shaft to the roof, and eventually the atmosphere, the hotel, apartments and penthouses duct their toilet gas extraction. This was challenging says Arnold as the penthouses are at the top of the building, so they had to be creative and accommodate the risers as best as possible with the apartments and penthouse designs. WSP also undertook the pressurisation of stairwells and lifts on this project.
Energy: “Interpreters between nature and man”
Arnold says the initial design brief was to make the building energy efficient since the Legacy Group commits itself to the Heritage Environmental Rating Programme in Africa. Sustainability therefore became an important part of the design brief. Franc Brugman of BAI says he strived to include sustainable technologies into the building’s design as much as possible. Generally we looked at the most energy efficient products that were within budget, says Maria Paschini from BAI. Originally 2.4 MVA of power was requested, but Eskom agreed on 2.2 MVA.
The entire team implemented energy savings ranging from energy saving escalators, strict lighting designs, energy saving card readers in rooms, timers on external and basement lights, lower wattage lamps with higher efficient fittings, local switching in all individual rooms and, electronic control gear on fittings. Gas cooking is used where possible and power factor correction is installed in the sub station.
Arnold says partial heat recovery from chillers aids in heating water for the apartments which adds in the energy saving methods. BAI and wet services engineers, Watsol, undertook shadow reports to track the sun’s position in relation to the building for optimal energy generation within the indirect (closed loop) solar water heating system installed on the roof. These panels, located on the roof, assist 30 000 litre electrical boilers. The boilers serve as standby due to the solar panels supplying adequate hot water for the development and this inturn adds to energy efficiency, says Arnold. Water saving water closets (wc) and urinals were also used. Insulation on hot water pipes and performance glass is used to reduce air conditioning heat loads.
A Satchtech energy management system assists with monitoring energy consumptions and enhancing the water and HVAC portions of the building envelope. Brugman says they were aiming for a thermally efficient facade to ensure that there will be no thermal build up in the structure, especially in the north and west facing facade”, he says. Arnold says an energy management system has been programmed to set points. Once 90 percent of the building electrical load has been reached, the energy management system undertakes specific steps, such as switching off the boilers, changing set points on air conditioning systems and/or switching off air conditioning systems until the system has stabilised. The steps are then reversed.
Special glass to prevent heat losses and gains has been used on the exterior of this architectural riser says Page. Generally buildings are south facing, but Legacy Corner is west facing, therefore the Maximillien restaurant and DΛVINCI is in direct sunlight. High performance specialty glass had to be used to decrease loads these sections will incur. Brugman says they were aiming for a thermally efficient facade to ensure that there will be no thermal build up in the structure, especially in the north and west facing facade”, he says.
Success: “They went out and happened to things”
Most of the coordination happened on site, which was crucial and spot on, says Page. WSP came in on budget and on time, ready for the World Cup. The result is a full on mixed use development with different components demonstrating the sheer complexity of the site in terms of size, space and, energy efficiency with proud and happy Legacy Group.