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The building's facade
Natural energy
Although the Green Building makes use of an extensive range of recycled materials and rainwater harvesting along with exterior insulation and other environmentally sound technologies such as double and triple glazing (and, at one time, using an energy saving control system that automatically received weather data directly from Met Éireann, using it to predict heating requirements for the following 48 hours) its main claim to sustainability lies in its energy production strategy.
Though hardly a hermetically sealed unit, the building does produce its own heat, hot water and electricity on-site through a range of renewable energy technologies. At the design stage, the decision was taken to utilise every available energy source, resulting in the use of solar panels, both photovoltaic and evacuated tube, wind turbines and a ground source heat pump.
While the solar panels and heat pump have both proved a success, the wind turbines have not. Tethered for several years, they are set to be decommissioned soon. The problems have been two-fold: firstly, their vibrations were heard in the penthouse apartments causing some discomfort for residents and, secondly, they failed to reliably produce power due to turbulence.
On the other hand, the solar sources are rather more useful. The annual output of the grid-connected system was initially estimated at 2,731 kWh, and currently runs at around 3,000 kWh.
The building exports surplus power to the national grid: "The electricity is given to the nation free," laughs Cooper, "five percent is for export," noting that currently electricity cannot be sold directly to ESB.
Nevertheless, as a measure of the building's success, regardless of any absconded potential profit as a result of the regulatory environment for electricity in Ireland, the value of the electricity the building produces now exceeds the cost of all the electricity required for the heating systems.
Additionally, the photovoltaic arrays have required no maintenance during their first twelve years other than the replacement of three fuses after a violent thunderstorm.
In the initial design, the roof-mounted wind turbines and photovoltaic panels charged a bank of heavy duty batteries. Batteries have a limited lifespan of around ten years, by which time it was anticipated that legislation would be in place to switch to grid-connected inverters.
high-efficiency evacuated tube solar collectors feed into the building's hot water supply, combined with a bore hole heat pump
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