The Application of Direct Current: the Power to Improve Building Sustainability

Session 13, Paper 2, CIBSE Technical Symposium, Liverpool John Moores University, Liverpool
11-12 April 2013

Ever since the “War of the Currents” (1) in the19th century, the use of electricity – as a provider of light, heat and power – has been a priority for engineers concerned with building engineering services. Over time, direct current (DC) gave way to the adoption of alternating current (AC) supply – principally because of the inefficiencies of long distance transmission. The subsequent development of semiconductor and microprocessor technology and their dependence on DC introduces the need to provide localised transformation and rectification at the point of use. Client demand for lower building running costs driven by rising energy prices has seen the building engineering services sector respond with the incorporation of low voltage lighting and the adoption of photovoltaic (PV) arrays. In some instances this has led to power being inverted from DC to AC only to later be rectified back to DC at point of use. The prejudices towards DC for power distribution are deep routed, perhaps dating back to Edison, Tesla and Westinghouse. But, with every office desk now hosting several often extremely inefficient transformer/rectifier units, building services engineers should embrace the power to improve building sustainability.