A hospital built for sustainability
New Cape Town Hospital saves money by going green
Seventeen storeys and 30 000m2 floor space, the new Netcare Christiaan Barnard Memorial Hospital boasts a range of green design principles and technology which are in line with global standards –setting the benchmark for environmentally friendly hospitals in South Africa. Some of the solutions implemented include a special double-skin façade, which is expected to save around R120 000 annually, and efficient lighting instalments, which will see a 40% reduction in electricity used for lighting. Read on and see for yourself!
The building’s ‘intelligent’ exterior façade comprises an external glass skin, with a void separating it from the building’s internal glass windows. This means that together, the internal glass windows and the exterior of the building act as a double skin, offering outstanding insulation to the interior hospital environment. The void within the two walls can be ventilated when the building needs to be cooled down, or closed to warm it up by means of louvres positioned between the two skins on roof level, which can either be opened or closed.
“The façade is also connected to wind driven extractors and motorised dampers which, in turn, are connected to the building management system. An intelligent and automatically controlled insulation layer enhances the energy efficient heating, cooling and ventilation technology installed in the building,” says Dr Friedland.
“It works like a giant Thermos flask; with the façade forming an insulation barrier which ensures significantly less dependence on the air conditioning units in the hospital for maintaining ideal internal environmental conditions. At the same time, the glass façade has an attractive visual effect and patients and visitors are able to enjoy the magnificent views of the harbour, mountain or city scape, depending on where they are in the hospital,” he explains.
Netcare’s environmental sustainability manager, Johan Durand says the building’s ‘intelligent’ exterior façade is expected to save Netcare Christiaan Barnard Memorial Hospital some 105 000 kWh of electricity annually (about R120 000 per year in energy bills!)
The heating ventilation and air conditioning system that serves the new hospital is based on a rational design that exceeds South African national building regulations, and is based on an advanced standard as recommended and applied by the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE). This allows for better filtration of air to further improve infection prevention and control, while offering greater energy efficiency. Further efficiencies will be achieved through using two water-cooled chillers housed on the roof.
A building management system (BMS) works to reduce the building’s cooling and heating requirements by means of a centralised control of all services within the hospital. “The system focuses on integrating all systems within the building into one environment to ensure that they all operate cohesively and to optimum efficiency,” adds Durand.
The BMS system also measures the air temperature along sections of the façade and controls the motorised dampers to either extract or trap warm air depending on climatic conditions outside. The facility’s heating, ventilation and air conditioning system services the internal environment through variable air volume systems. These can be ramped up or down depending on the specific requirements of each individual ward.
“These air-handling units are equipped with economy cycle dampers to monitor outside air temperature. When the outside conditions are favourable, the utilisation of chillers to treat the air and fulfil internal demands is reduced. This system supplements the advantages inherent in the design of the ‘intelligent’ façade. The air conditioning system generates waste heat, which is harnessed to pre-heat the domestic hot water for the facility. The hot water is generated mainly by efficient heat pumps that use three times less energy than conventional electrical heating elements. The hot water storage vessels are fitted with electrical heating elements as a back-up measure,” explains Durand.
The piping system has been designed in such a way that domestic hot water can be circulated throughout the entire building, thereby reducing wastage due to hot water being available close to the points of use. The domestic hot water integration with the air conditioning is expected to save 34 300 kWh of energy annually.
“We are effectively harvesting every little bit of heat energy and re-using it as an additional form of energy. Previously, this precious resource would have gone to waste, but now we are able to harness it to good effect,” says Durand.
The hospital is also equipped with a sophisticated grey water harvesting system, which channels waste water from the renal dialysis filtration plant and the autoclaves used to steam sterilise medical equipment, to the ablution facilities. “Grey water harvesting and re-use is expected to save about 3 204 kilolitres of water a year, ” explains Durand.
“In addition, we have fitted low flow showerheads, which use half of the water of a conventional shower, and aerator equipped taps on all hand washbasins to reduce water usage. “Where these fittings have been used in other Netcare hospitals, they have achieved significant water savings.”
Lighting: According to Durand, the hospital has a mix of flourescent and LED lighting, resulting in a 40% reduction in electricity used for lighting.
Dry-type transformers: Two high efficiency dry type transformers, which are situated on the roof of the building, supply electricity to the facility and will contribute to electrical cost saving.
Green lifts: Regenerative lifts are helping to further drive down the 17-storey hospital's energy consumption. Dr Friedland explains: “Also helping to reduce future energy costs is the mechanism underpinning the facility’s regenerative power lifts, whereby the force of gravity is allowed to do the work when the lift is descending, and the motors act as generators, supplying the energy into a power bank for utilisation when the lifts go up.”
Dr Friedland observes that these features contribute to the environmental sustainability of the hospital and, by extension, help protect the country’s energy resources.
“Although hospitals are classified as low impact concerns in terms of carbon emissions, Netcare nevertheless takes its environmental responsibilities extremely seriously.”
“Efforts to conserve water and electricity should be high on the agenda of each and every South African, and we are committed to limiting our impact on the environment and to the judicious and sustainable management of our natural resource consumption. Netcare’s sustainability strategy aims not only to enhance the robust financial performance of the group into the future, but also to help ensure the future of the South African environment. The group’s impact in the environmental arena has shown that these two objectives are not mutually exclusive,” concludes Dr Friedland.
Information and images provided by Netcare Christiaan Barnard Memorial Hospital.