The focus was to design a building in the most cost effective way for low energy use. To achieve this objective the following aspects were implemented:
The building is faced north in order to maximize the natural lighting from the windows on the North elevation. Extensive roof overhangs keep the windows and walls in the shade during the hot summer months to control heat gain from direct sunlight.
The roof is designed to allow natural daylight from the south into the building. The required minimum light level was 500 Lux and the light level achieved was between 600Lux and 800Lux.
Walls and roof are well insulated to ensure minimum heat gain in summer and minimum heat loss in winter. 120 Photovoltaic panels were installed on the roof to provide 30KVA power to the electrical network in the building. This is sufficient to run all the light fittings and computer equipment in the showroom, warehouse and the offices areas. Excess energy generated through the photovoltaic panels is stored in a battery bank to be used at night and on cloudy days. The electrical network is still connected to the local electricity grid as a backup.
Hot water is generated by a solar heating system. A two stage evaporative cooling system is installed to maintain a comfortable temperature in the building of 23.5°C with a low energy demand of 28VA/m 2 . Hot air in winter is recirculated.
Two steel box gutters on the Eastern and Western side of the building carries the rain water to eight 10 000 liter water tanks at the South side of the building. This water will be used for the irrigation of the landscape around the building. The decision to use only indigenous plants with low water consumption in the landscaped architecture was a high priority. Motion sensors control when and where artificial light is needed. Energy saving light fittings is used throughout.
Sophisticated metering equipment is installed to monitor the energy consumption. This equipment allows for off-site web-based monitoring as well as energy control. The data from the system helps to manage the building effectively. A monitor at the building entrance constantly displays the energy performance of the building. The results of all the energy saving systems are measured in Kwh/m 2 over a period of one year. The table below compares the energy consumption of the building to conventional designs and indicates an energy saving of 72%. It is estimated that the extra capital cost should be recovered within 4 years.