By Larry Wash
Published in the June 2007 issue of Today’s Facility Manager
This summer, energy efficiency for commercial buildings is more critical than ever. The Energy Information Administration reports that this year, despite recent increases in world oil production, oil consumption will continue to grow and strain supplies. Natural gas prices are projected to accelerate during the height of the cooling season. And electricity prices are expected to climb at a rate of 3% during 2007. Clearly, energy efficiency is gaining importance as federal and local governments promote sustainable concepts to help stem the impact of commercial buildings on consumption.
Air conditioning systems in commercial buildings are the highest contributors to peak electrical loads during hot weather. By following these tips, facilities professionals can cut energy use and reduce the demand on regional and national energy grids—lowering rates and risks for all.
Peak usage determines rates. Monitoring power usage carefully through the building automation system helps to target possibilities for load shedding or load shifting to avoid power demand peaks. The charge, which determines the facility’s seasonal rates, is based on the highest rate at which the customer used energy during a billing cycle. Even brief usage peaks can significantly increase a facility’s utility costs. Close monitoring will help determine if there are inefficiencies in the cooling equipment to plan for replacements or updates during the winter.
Demand charges can be controlled. Load shedding strategies could include shifting major power demands from daytime to night, when there is less strain on the energy grid and rates are lower.
One way to shift demand is to bring in cool outside air at night and then use window film or awnings to block the sun from heating indoor space during the day. By pre-cooling the building and limiting the sun load during the hottest hours, it is possible to delay the onset of peak cooling loads.
Flexible habits can cut usage. Having workers come in an hour or two later than usual can have a major impact on demand charges. It also helps to use rooms that can be cooled individually, which avoids cooling entire buildings or floors during off-hours. Lighting sensors synchronized with daylight savings time shifts can save significant energy as well.
Alternative systems can help. To decrease peak load, raise efficiency, and lower environmental impact, more facilities are implementing innovative heating and cooling systems, from solar and geothermal systems to ice storage.
Occupant comfort affects productivity. One common complaint heard by facilities is about temperature. Studies show that thermal comfort impacts worker and student performance as well as patient outcomes at hospitals.
When it is hot outside, comfortable indoor temperatures can generally be up to the mid 70s. Any hot spots caused by windows or equipment should be corrected, and thermostats should be placed in the center of the room, away from equipment or windows.
Summertime air quality is important to facility health. Maintaining indoor air quality (IAQ) is also critical to productivity. Studies indicate that Americans spend up to 90% of their day indoors. According to the U.S. Environmental Protection Agency, air quality inside buildings can be two to five times worse than outside air, and building-related illnesses account for $60 billion of annual productivity lost nationwide.
In the summertime, facility managers have the challenge of ensuring ventilation is up to ANSI/ASHRAE standards while keeping comfort levels ideal and maintaining efficiency. There are many sensors that can help monitor air quality factors and deflect the typical problems related to allergens and other quality issues associated with a lack of outside air.
System checkups maintain efficiency. If all the pre-season work has been done, it is less likely the facility will face cooling emergencies, and summer maintenance should run smoothly.
Some maintenance considerations include:
- Test motors when the system is running at its highest to make sure they’re not overloaded;
- Inspect pumps and cooling towers;
- Ensure contactors are all secure and within tolerance;
- Starters and motor starters are all operating;
- Keep a close eye on refrigeration leakage;
- Make sure condenser and evaporator coils stay clean; and
- Check that drain pans are sloped for correct drainage and that metal pans are not rusted.
By taking the right measures before and during the cooling season, facility managers can rest easy that the building stays high performing and energy efficient throughout summer’s most demanding days.
Wash is vice president of services and contracting for Trane in Piscataway, NJ. He is responsible for leading and managing the Americas Services and Contracting business, which delivers integrated HVAC solutions to Trane customers.