Spy on your Building
Building Well-Being | Issue #2 | November 25, 2005
Analysis for energy efficiency made easier by data logging
While driving home from work the other day I see an advertisement for a clothes dryer that proclaims the appliance to be 32% more efficient. Efficiency is the word of the day. Or should I say more efficient? And how much more? Is the above dryer 32% more efficient than its competitor's models or is it 32% more efficient than it used to be? And if this is indeed a personal best for that particular dryer, how inefficient was it? Similarly, the newest craze of 'energy efficient' buildings will remain a sales pitch until owners and builders are willing to establish benchmarks and standards that can be used to make informed buying decisions.
Benchmarking energy consumption in buildings has been defined as '...comparing how much energy is used in a building to an average or theoretical standard.' Comparing one building to another is useful in a limited number of cases. This notion of 'average' works well when the buildings in question vary little in their location, construction and general use. Suburban housing, commercial franchises and some federal buildings are good examples of where energy consumption levels may be standardized for ease of comparison. But in the vast majority of cases, variance in buildings is so great that sometimes the only useful benchmark in analyzing energy efficiency is knowing a particular building's patterns and trends. And the key to that is data logging!
Simply put, data logging is the measurement of values over time. Monitoring a building's temperature, for example, could help identify problem areas or periods of the day. Furthermore, when gauging the effect of any energy efficiency controls put into place, having pre and post-data is crucial. Collecting the data is now easier than ever. Temperature loggers are now as small as a bottle cap and record for weeks on their own power. Small palm-sized data loggers are available that can be connected to any device that has an electrical output such as cooling fans, air-intakes and furnaces. These devices are downloaded to a computer where graphs and tables aid in data manipulation and interpretation.
The information gathered through data logging is invaluable to anyone interested in energy efficiency improvement. For building managers benchmarking provides the foundation for energy management decisions, identifying the best candidates for upgrades. For those who have compliance and/or accreditation concerns, having a building's energy consumption data summarized and documented helps answer questions about energy use from upper management, vendors, investors, or government agencies. And who doesn't like positive publicity? Being able to demonstrate a building's improved energy efficiency or reduced energy consumption provides a great basis to communicate an environmentally friendly image. Having the data makes every decision easier so remember...you can't manage what you can't measure!
David Hamilton is the President and Andrew Birch is the Vice-President and Senior Consultant of Redwood Environmental. They can be reached at (403) 680-5995