Ways to Save Money and Energy

Ways to Save Money and Energy
September 2004

When you read the business section of your local paper, you often learn that a company is filing for bankruptcy protection or is in danger of losing its building to a bank. Bankruptcies and foreclosure are often the result of mismanagement or ineffective facility maintenance. Perhaps the company in question is relocating to another state to realize the greater profits. Yet the owner of an adjacent building might be realizing generous profits because the manager and maintenance staff implemented an energy management plan several years earlier. The fact remains that a building is an investment that must be maintained effectively to run efficiently. In addition to knowing how a building works, today’s building professionals need to know how it works most efficiently.

Energy savings through improvements in operations can be achieved with minimal expense, however, a preventative maintenance program cannot be applied until a standard operating procedure (SOP) has been developed. Establishing and implementing a SOP program in an effort to reduce energy costs with little or no layout of capital funds can be obtained through minor operational changes, such as improved maintenance or repair of malfunctioning equipment. SOP programs can be developed overnight, but their implementation is continuous. For example, filters have to be changed routinely, HVAC coils must be kept clean, and motor fan bearings must be lubricated. All of these tasks are essential steps that are included in SOP programs.

The following guidelines will help you to design a comprehensive SOP program. The scope of these guidelines is broad, as many diverse and alternative mechanical systems exist in any given building or facility. Although some of these procedures may not be applicable in your facility, the majority of items listed will be helpful points of reference as you develop and implement your own SOP programs.

Heating and Cooling Guidelines

• Reduce use of heating and cooling systems in spaces that are used infrequently or only for short periods of time.
• Heat office building to 68°F when occupied, 50° to 60°F when unoccupied. This does not mean that air should be cooled if the temperature exceeds 68°F. Interior office spaces tend to experience significant heat gains due to lighting, equipment, and people. Systems servicing most areas use a combination of recirculated inside air and some outside air. As a result, the temperature may tend to stay at or above 68°F.
• Preheat a building so that it achieves 65°F by the time occupants arrive. Complete warm-up during the first hour of occupancy. Lighting, people, and office equipment use will aid in warm-up.
• Turn heat off during last hour of occupancy.
• Cool office building to 76°F when occupied. Do not utilize mechanical cooling when unoccupied. Special consideration, however, must be given to computer rooms. Generally, the primary criterion is a constant temperature/humidity relationship. Manufacturers should be contacted to determine permissible ranges. Cooling usually is required while the equipment is operated, but should not be used to lower room temperature below the range of 72° to 76°F.
• Begin pre-cooling operations so the building is at operating temperature by the time occupants arrive. Complete cool-down during the first hour of occupancy.
• Minimize outdoor air.
• During cooling season evening to night hours, flush the building with cooler outdoor air.
• Allow variations from 30% to 60% relative humidity in occupied spaces.
• When appropriate, consider closing supply registers and radiators, reducing thermostat settings, or turning off the electric heaters in lobbies, corridors, and vestibules.
• Where sill-height electric heaters are used, adjust thermostats so that heat provided is just sufficient to prevent cold downdrafts from reaching the floor.
• Turn off humidifiers whenever the building is closed for extended periods of time, except when process or equipment requirements take precedence.
• In mild weather, lower the cooling effect by running room cooling fans at lower speeds.
• Ensure that all exhaust fans move no more than the amount of air that they were designed to expel from the building.
• Turn off reheat in all areas during the summer, except where equipment requirements necessitate humidity control.
• Reduce internal heat generation as much as possible during the cooling season. Typical source of heat generation include lighting, people, machines, and cooking equipment.
• Adjust and balance system to minimize overcooling and overheating, which result from poor zoning, poor distribution, improper location of controls, or improper control.

Central Plant Guidelines

• Operate one of the multiple compressors and chillers at full load, rather than two or more partial loads.
• Ensure that the condenser water system is operating at design temperature.
• Ensure that the chilled water pumps and cooling tower fans are operating as designed.
• Operate boilers at design pressure and temperatures.
• Consider using cold, idle boilers as an alternative to using hot standby boilers if facility size and steam demand will allow.
• When making these types of changes, the system may need to be rebalanced. Operate only the heating water pumps necessary.
• Examine operating procedures when more than one boiler is involved. It is far better to operate one boiler at 90% capacity than two at 45% capacity each. The more boilers used, the greater the heat loss.
• Check flue gas analysis on a periodic basis: the efficient combustion of fuel in a boiler requires burner and adjustment to achieve proper stack temperature, CO2 level, and excess air settings. Check settings to provide stack temperature of no more than 150°F above steam or water temperature. There should be no carbon monoxide. For a gas-fired unit, CO2 should be present at 9-10%. For #2 oil, 11.5-12.8%; for #6 oil, 13-13.8%.
• Adjust the air-to-fuel ratio of firing equipment and maintain it properly. If there is insufficient air, the fire will smoke, causing tubes to become covered with soot and carbon, and thus lowering heat transfer efficiency. If too much air is used, unused air will be heated by combustion and exhausted up the stack, wasting energy.
• Use an oil additive to provide better combustion.
• Use automatic viscosity controllers to achieve better oil combustion atomization. Automatic viscosity controllers also permit mixing or using different grades of oil.

Engineers, facilities directors, building managers, maintenance personnel, and many other professionals are becoming aware of the need for an energy policy. Everyone reaps the benefits, in the form of job security, bonuses, increased salaries, and personal gratification, when energy plans are implemented and when everyone is striving for the same goals. To develop and implement an energy management system, it is important to understand the basic principles of energy and the systems in your building. For example, what is energy? What affects energy usage in buildings? How do you recognize a heat source, and how do you predict the impact this heat source will have on mechanical functioning? How can heat flow affect heat transfer? Why is it important to understand water treatment and the exterior and interior building design? These questions all point to the need for designing and implementing an energy management system. Answers to all of these questions can be found in BOMI’s Energy Management and Controls textbook. For more information on this course, please contact BOMI at 1-800-235-2664 or email service@bomi-edu.org.