Portcullis House Case Study

Portcullis House, opposite the Palace of Westminster, which has just been handed over for use as the New Parliamentary Building, has been specifically designed to be energy saving and environmentally-friendly, using, it is claimed, just 25% of the energy which would be required for a conventional building of the same size. Its principal purpose is to provide office accommodation, occupying the upper five floors, for MPs and their secretaries. A feature of the design is the glass-roofed central courtyard, where there is a restaurant and reading facilities, as well as an ornamental water feature.

The courtyard is provided with Warmafloor heating/cooling system designed and installed by Warmafloor to provide comfort conditions in this space. Warmafloor's system using Polybutylene (PB) underfloor heating pipe was selected for the project not only for its technical excellence but also the Warmafloor pipework is guaranteed for 50 years and has an anticipated life that will last the 200 year design life of the building. No other underfloor system can match this criteria. The courtyard form of the New Parliamentary Building provides maximum exterior façade area, and therefore daylit offices for the members, with borrowed light illuminating the corridors behind them, reflected from light shelves above the windows, through glass partitions at the top of the walls.

The building employs a mechanical ventilation system using 100% fresh air, which is drawn in at the base of the 14 turrets. The air is circulated round the building via bronze airshafts to each room and underfloor ducts, having very low pressure loss air handling and duct system components. The chimneys also exhaust stale air to the outside.

The cooling for the air conditioning uses free cold water from a borehole in the basement.

The high thermal mass building fabric enables heat to be stored until it can be used, evening out daytime and night-time temperatures. Gas-fired condensing boilers provide the main heating.Portcullis House has a 200 year design life, compared with the 20-30 years of most buildings. Maintenance of the fabric will be minimal, because of the durable, long life materials used: this also means embodied energy has been reduced.