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Furthermore, the building leans back toward the south, where floor plates are stepped inward from top to bottom, providing natural shading from the most intense direct sunlight. On the north side, where there is no direct sunlight, the glazing is clear.

The south-facing facade steps out at each floor, becoming self-shading.

When heating is required, two gas-fired boilers generate hot water for use in convector heaters in the offices, in the debating chamber, and for the under-floor heating of the foyer. The hot water runs through heating coils in the air-handling units, warming incoming air. To reduce the energy required to circulate the water around the system, Arup chose variable speed pumps, which allow the water flow to be increased or reduced to meet demand.

Air for ventilation enters offices through grilles in the floor. Vents in the facade are provided in the external offices for natural ventilation. When the vents are opened, local cooling and heating systems will be deactivated. During winter, heat and moisture will be recovered from the outgoing air and used to condition incoming ventilation air using devices called hygroscopic (the property of readily absorbing water) thermal wheels.

In the summer, comfortable internal temperatures are maintained by chilled beams, rather than electric chillers. The beams are located in the office ceilings, where cold ground water passes through the heat exchanger and is circulated through these beams. The ground water is pumped to a height of 410 feet at a temperature of 53 to 57 degrees Fahrenheit from the aquifer below the building via two specially drilled boreholes. This cold ground water is also used directly in the cooling coils of the air-handling units to cool the fresh air entering the building.

The use of this natural resource for cooling reduces electricity consumption and thus saves money. Boreholes use less energy than do conventional chillers and cooling towers, and they are less expensive to install and maintain. Following circulation, the ground (aquifer) water is used to flush toilets before being discharged, further reducing water consumption.

As shown, environmental comfort is determined by air movement, ambient temperature, humidity, air intake and exhaust, and solar radiation. Building systems can be optimized only if the designers understand the interaction and interdependence of each system with every other system. Arup specializes in what is called flow engineering, which is the process of analyzing, predicting, and controlling the movement of fluids using mathematical models and experimental techniques.

As building owners are realizing, systems are only as good as their consistent performance. Surveys have indicated that 75 percent of buildings in the United Kingdom are operating incorrectly, have inappropriate operation and maintenance contracts, or are wasting money through inefficient energy usage. Arup engineered a sophisticated Building Management System (BMS) to maintain and control conditions within the GLA building. The BMS is programmed to maximize the use of the energy-saving systems and ensure other mechanical systems are used efficiently. For example, the chamber and committee rooms of the GLA building will only be cooled when they are occupied. During peak summer conditions and when the chamber is not in use, large air vents allow natural ventilation. The BMS also controls the flow and temperature of the air entering the chamber and ensures the occupants are provided with the required amount of fresh air.

Arup’s environmental expertise continues to be applied beyond the GLA envelope. The firm has worked closely with the mayor of London, Ken Livingstone, and the GLA over the past two years to develop a comprehensive set of policies and proposals that will improve London’s air quality. These range from encouraging environmental best practice from businesses and new developments to investigating the feasibility
of a low-emissions zone (an area from which the most polluting vehicles are excluded).