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Slash your HVAC costs

Here are ten things you can do right now

By Alan Barnes, Jr.

September 18, 2001

 

When President Bush outlined his energy plan earlier this year, heencouraged U.S. companies to explore new ways to conserve energyresources, including improving the efficiency of high-use commercial andindustrial systems.

For plant managers, this is a signal to take a closer look at their heating,ventilating and air conditioning (HVAC) systems. An HVAC system canaccount for as much as 30 percent of a building's energy consumption.

 As much as 15 percent of that energy can be conserved by changingexisting practices.

Surprisingly, it's not the primary HVAC equipment, such as chillers, thatconsume the most energy. Instead, it's the auxiliary equipment. In theU.S., HVAC auxiliary equipment uses approximately 1.5 quadrillionBTUs annually, the same amount of energy that it would take to run 23million automobiles, according to the U.S. Dept. of Energy. This energyoperates the fans and pumps that provide office and building ventilation,distribute heating and cooling, and support the primary HVACequipment.

The increased energy usage by auxiliary equipment is attributable toseveral factors, including indoor air quality concerns, greater filtrationand higher ventilation rates.

How can you reduce the amount of energy your system uses and cutoperating costs? The solutions run from the simple to the complex. Acombination of the following suggestions can reduce your energy wasteby as much as 15 percent.

Ten tips for slashing HVAC costsSchedule an energy audit. An HVAC auditor evaluates the efficiency of primary and auxiliary equipment, determines the condition of the systemand analyzes the impact of potential system improvements. Upon

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completion of the audit, you'll receive a report that documents the useand occupancy of your building, its condition and that of the HVACsystem.

The report also recommends ways to increase efficiency throughimprovements in operation and maintenance items, as well as through

the installation of energy conservation measures. Facility managers canrequest energy audits from most utility companies and mechanicalservice providers.

Have the HVAC design evaluated. Is your HVAC equipment properlysized? If you're in the market for a new system, determine the life-cyclecost of several HVAC systems to find the best design for long-term use.For a new system, also consider installing modular boilers or dual-fuelboilers.

Check your distribution systems. Make sure that hot water and steampipes are insulated properly and that ducts are gasketed or sealed withmastic. If you're considering a new system, avoid fiberboard ducts and

make sure that flexible duct runs are no longer than 10 ft. In addition,specify low-leak dampers, and remember that areas with high ventilationrates are good candidates for heat-recovery equipment.

Evaluate HVAC controls. If you haven't done so already, installprogrammable thermostats or timers to regulate the temperature inunoccupied areas and consider purchasing demand-limiting controls.

In addition, consider installing an energy-management system andzoning your building, which is an effective control strategy for larger facilities. And remember that ventilation equipment should be off or closed when the building is unoccupied.

Re-evaluate heating equipment before winter. Remember to avoidany form of electric resistance heat if possible. If you're considering anew system, specify high-efficiency units with a low KW/ton rating for packaged units. The higher upfront cost will pay for itself over timebecause of long-term energy savings.

Automate your HVAC system. One of the least expensive methods of reducing your HVAC energy consumption is to program the system tominimize its run time, to operate in the most efficient operating rangesand to alert operators when the equipment is drifting from its maximumefficiency. A computerized control system can eliminate as much as 5percent of energy waste.

Look for "free cooling" opportunities. If the facility doesn't need tocontrol humidity, use a water-cooled or free-cooling system. Free coolingcan be accomplished in two ways. Water-side economizers use water from cooling towers to satisfy partial loads. Air-side economizers satisfypartial loads by using 100-percent outside air in the air-handling system.

Optimize your operations. Depending on the complexity of the HVACand control systems, you can use additional system optimization

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measures to increase efficiency. These can include sequencing thestartup of boilers and chillers for optimal loading in the daily cycle, timingboiler or chiller startup to meet building temperature requirements atopening times with minimal off-hours waste, and fine-tuning temperaturecontrols and air-supply systems so that fans, chillers and boilers operateat optimum efficiency during the day.

Keep your HVAC system clean. Careful maintenance improves systemefficiency; a dirty one must work harder and uses more energy. Cleaningequipment and replacing filters on a regular basis will save energy andlower costs.

Schedule an annual HVAC maintenance review. This includesinspecting parts, verifying fan speeds, making seasonal adjustments inmild weather and checking refrigerant levels in the sealed subsystems of chillers, heat pumps and air conditioners.

Each of these measures can help facilities to reduce energyconsumption and costs—and the time to do them is now. Energy experts

project that the energy crisis currently crippling California will eventuallymove from West to East, leading to higher energy costs and potentialblack-outs. For this reason, it's imperative that some businesses—especially those that can't afford a capital-intensive HVAC project for their industrial and manufacturing facilities—adopt conservationmeasures and install cost-cutting devices and materials.

 Alan Barnes Jr. is chief operating officer of Atlanta-based Aircond Corp.He can reached via e-mail at mailto:albjr@aircond.com.