The Deutshe Schule in Pretoria (DSP) is intent on going off the electricity grid – and is working towards producing its own power.
When it comes to sustainability, the DSP’s main concern is electricity. So the first step was to turn their attention to lighting and heating, which demanded that the windows be refitted.
The school replaced existing metal frame windows with single, low emittance safety glass uPVC windows.
The school also installed motion sensors for lighting in classrooms and walkways, and is gradually replacing existing light bulbs with energy efficient ones.
For educational purposes, three heating systems are showcased. Fan coil units, where warm air is released from colourful “Prihoda” ducts, “Tropical 95” radiators and hydronic floor heating were introduced. All are powered by a central heat pump. While underfloor heating is the best choice for heating a room, cooling is achieved effectively with fan coil units.
Since the school is trying to limit energy use, especially at peak times, the system is switched off during school hours. The two 2000L heat pumps both have a capacity of 19 kW.
In addition to the heat pumps, the school carries close to 50 kW solar panels on its roofs.
All generated power is used in full before switching to Eskom power. Any surplus solar power is pushed into the internal grid for use in other blocks, or stored in the form of hot water.
A continuous challenge for the DSP is the electricity billing system. “We would like to approach the Tshwane City Council and join hands to achieve common goals,” says Andreas Wagner, regional sales manager for Bosch Solar Energy and a member of the DSP board.
“We can supply the city council with our surplus power, but for our annual October Fest we would need a bit more from them. Technically this is very easy; it is mainly a software issue in combination with the right meters. But it is a big battle to get through to the right people.”
Further sustainability plans for the school include rainwater harvesting, replacing the electrical geysers with solar powered ones, adding a cooling option for the fan coiled units and installing a solar power storage battery for use in the media centre.
Installing sub-meters, and a metering and management system so that non-essential loads can be switched off during peak hours, is also on the cards.
The full article appears in the February – March 2014.