Submetering to Evaluate Energy Use in Office Buildings

Abstract

The Lower Colorado River Authority (LCRA) has been collecting energy and demand data on its 75,000 square foot, five-floor Shapiro office building in Austin, Texas since June 1982. The building provides an ideal laboratory for studying energy-saving modifications because the major loads are metered individually. Sixteen submeters are used to monitor the computer mainframe, computer room HVAC, lighting, elevators, appliances, heating, and air conditioning. The only way to accurately test the effectiveness of an energy savings modification is to isolate the associated energy consumption. Typically. energy conservation evaluations are based on energy (or demand) data from the metered total building, and changes in a specific load are obscured by unidentifiable load fluctuations within the building. Accurate knowledge of the energy consumption of individual loads (verified by measurement rather than predicted by theoretical calculations) can provide valuable insight into the design of more energy-efficient buildings.