[ Page 1 of 8 ]

Technology and ingenuity contribute to energy-efficient performance

By Sara Hart

Continuing Education Use the following learning objectives to focus your study while reading this month’s ARCHITECTURAL RECORD / AIA Continuing Education article. Learning Objective: After reading this article, you will be able to: 1. Discuss what computer modeling can offer to the architectural profession. 2. Explain changes in business procedures that will result from sharing computer models. 3. Describe how structural-steel systems will benefit from computer modeling.

The strangely beautiful egg shape of the Greater London Authority (GLA) by Foster and Partners has as much to do with sustainability as it does with architectural design. The architect and its engineering partner, Arup, decided early on that the building would be designed as an energy-efficient entity, as opposed to a typical structure that has energy-efficient devices tacked onto it late in the design-development phase. This meant that the envelope itself had to limit heating and cooling loads. The result is a spherical envelope that is itself an energy-saving device. A sphere has 25 percent less surface area than a cube of the same volume. Less surface equals less heat and cooling gains.

Arup engineered every aspect of the facade to minimize heat transfer across the external surfaces. The maximum allowable solar heat gain for each external square meter of building was determined by constructing and analyzing heating- and cooling-load models. The use of highly insulated panels combined with high-performance glazing reduces potential heat loss from the building. The greater the need for solar shading, the greater the cladding-to-glazing ratio. The use of these panels combined with high-performance glazing reduces potential heat loss from the building to a level well below that required by the building regulations.

Structure played a major role in creating an efficient and integrated network of systems. A diagrid structure supports the north-facing facade. Hot water courses through horizontal members, 12 inches in diameter, warming the atrium and creating, in essence, London’s largest radiator. Structure that doubles as plumbing illustrates the economy of systems integration.