Exceeding Energy Consumption Design Expectations

Operational building performance often fails to meet that predicted at the design stage by as much as two to three times. Many reasons for this difference have been identified and widely reported, however, the problem still continues to occur. A case study new 'energy efficient' fully air conditioned office building has been monitored since occupation in June 2010 to observe the difference between operational energy consumption and design targets. In the first full year of operation (2011) the building consumed 208.7 kWh m-2 yr-1, 83% of the expected energy consumption (250 kWh m-2 yr-1). This dropped further to 176.1 kWh m-2 yr-1 in 2012 (70% below expected). Factors affecting building energy consumption have been discussed and appraised in respect to the case study building. Recommendations have been made for successfully meeting future building energy design targets. A number of energy saving technologies have been installed during the monitoring period such as LED lighting, voltage optimisation and thin client. An appraisal of these is also given, along with the performance of the photovoltaic panels and rainwater harvesting in place from the outset