Energy conservation in large buildings

As energy prices rise, newly energy aware designers use better tools and technology to create energy efficient buildings. Thus the U.S. office stock (average age 20 years) uses 250 kBTU/ft² of resource energy, but the guzzler of 1972 uses 500 (up×2), and the 1986 ASHRAE standards call for 100–125 (less than 25% of their 1972 ancestors). Surprisingly, the first real cost of these efficient buildings has not risen since 1972. Scaling laws are used to calculate heat gains and losses of buildings to obtain the ΔT(free) which can be as large as 15–30 °C (30–60 °F) for large buildings. The net thermal demand and thermal time constants are determined for the Swedish Thermodeck buildings which need essentially no heat in the winter and no chillers in summer. The BECA and other data bases for large buildings are discussed. Off‐peak cooling for large buildings is analyzed in terms of saving peak‐electrical power. By downsizing chillers and using cheaper, off‐peak power, cost‐effective thermal storage in new commercial buildings can reduce U.S. peak power demands by 10–20 GW in 15 years. A further potential of about 40 GW is available from adopting partial thermal storage and more efficient air conditioners in existing buildings.