Portfolio - Cardiff University
The extension was designed in accordance with Approved Document Part L2 of the time.
To minimise energy costs and future maintenance, Cardiff University were keen to minimise the use of conventional building services solutions in the design of the building. Accordingly, the first floor offices were designed to be naturally ventilated via roof mounted Monodraught ventilation units . Due to the sheltered nature of the courtyard, ventilation units with boost fans powered by photovoltaic panels were specified. Where the offices do not have external windows, 'Suntubes' have been incorporated into the roof design to admit daylight to minimise the use of artificial lighting.
The ground floor foyer and refectory are ventilated via three large Monodraught ventilation units located on the first and ground floor roofs. This ventilation design does not rely on openable windows at ground floor level, due to the potential security risk.
It was recognised that in high heat gain areas, such as the ground floor seminar rooms and servery mechanical cooling would be required to maintain an acceptable temperature. The principle adopted for this was a four pipe fan coil system utilising the exisiting chilled water and low pressure hot water heating systems adjacent. this system ensures that energy wastage would not occur due to the heating system fighting with the cooling sysytem which can happen with seperate heating and ( supplementary ! )cooling systems employed within the same building. no additional heat or coolth sources were added nor existing systems increased to cater for this extension. new inverter controlled energy efficient pumps were installed to all new circuits feeding the extension
Due to the weight restriction on the new extension and the highly visible location of the roof from the surrounding wings, it was decided to endeavour to keep the main roof clear of mechanical building services plant. The mechanical ventilation units are fitted with heat recovery cross flow heat exchangers of approximately 70 % efficiency with inverter controlled energy efficient fans and have been sustainably sourced from a local manufacturer
The ground floor of the extension has underfloor heating which allows the heating system to operate at far lower temperatures than would normally be the case to provide the equivalent internal conditions. This was coupled with the installation of energy saving compensation heating controls to vary the heating water flow temperature to the extension with its varying internal requirements. The entrance lobby utilises a sliding door arrangement. Both of these measures help to minimise convection heat loss from the ground floor accommodation.
Energy saving lighting controls in the form of personell infra red detection were incorporated throughout to avoid unnecessary waste of energy due to light fittings being left on whilst the area in question is unoccupied.