1. Thermostats. An improperly calibrated thermostat will read the wrong temperature and therefore adjust to the wrong temperature. When the thermostat reads 72 degrees, it might actually be 1 to 5 degrees higher or lower and will adjust the heating or cooling up or down according to that incorrect temperature. The fix: Calibrate your thermostats. Every last one of them.
2. Economizers. This happens all too often: economizers on air handling equipment working incorrectly – or not working at all. Faulty controls or slipped linkages cause the dampers to get stuck in one position. Someone makes a temporary fix, perhaps by sticking a 2×4 into the outside air damper to keep it open, until the repair can be made. But they forget about it, so it stays open when it should be closed. The fix: Check economizers. Repair ones that are not working. Take out the 2x4s.
3. Variable Frequency Drives. These can be great energy savers because they vary the speed of the motor they’re serving according to the requirements of the system. The energy savings is proportional to the cube of the rpm. For example: a 10% reduction in rpm will reduce energy use on a motor by 28% (.9 x .9 x .9 = .72). So a drive that runs at 60 Hz at full speed will use 28% less energy running at just 54 Hz. But if the VFD malfunctions, the building engineer might put the drive into the bypass position, i.e., running at full speed, while waiting for the repair. But the repair never happens, so the motor keeps running at full rpm, squandering its energy saving capabilities, and possibly causing additional problems. The fix: Take VFDs off bypass so the motor can be properly controlled.
4. Coils. HVAC coils get dirty, and the buildup of dirty – and hazardous – biofilm makes the system work harder than normal, reducing its efficiency. Dirty coils can also diminish indoor air quality and make people sick. The fix: Hire a properly trained technician to clean the coils with appropriate equipment and a specialized steam solution that gets deep into the coils. This technique removes not only particulate matter but also the biofilm.
5.Equipment. Equipment that should run only during normal operating hours, but instead runs constantly, wastes a lot of energy. Lights, air handling systems and pumps, as well as personal use equipment such as computers, chargers, heaters or small fans under or on top of desks, all have the potential to be left on 24/7. The fix: Install timers or motion sensors on lights. Use programmable thermostats everywhere you can – and make sure they are programmed correctly. Post reminders all around the office to encourage people to turn off/unplug equipment when they leave, and use power strips so they can just flip one switch to turn off all their personal items when they leave.
6. Building Automation System (BAS). A BAS can be complex, increasing the risk of improper use by the operator. The fix: Do not install a BAS that is more complex than required. Properly train – and retrain – staff on the BAS. Work with the supplier to provide adequate training and support for each new staff person that has responsibility for that system.
7. Submetering. Most buildings have only one electric meter. Sub-metering the lighting, HVAC system, and plug loads will show which areas use more energy. Then you can address specific problem areas. You will also know when there is an unexpected increase in energy use so you can fix small issues before they become bigger ones.
How do you get started? An energy audit is one of the best ways to find low- and no-cost ways to reduce energy use, as well as opportunities for higher payback fixes that conserve more energy but require a longer payback period. An audit can be done in-house if you have qualified people. Or hire a professional audit team so you won’t have to take your team away from their normal jobs. The auditor should be knowledgeable on codes and ASHRAE standards, and be familiar with HVAC and lighting design and/or building operations. Learn more about energy audits, including a white paper on how to select an energy auditor in this article.
To get started, look at the systems in your facility like you are a potential buyer. Bring in some trusted salespeople for the various equipment and systems in the building to find out if there are better ways to operate them. Be informed about economizers, variable frequency drives, and proper cleaning of coils. Maybe there are new advances in equipment and systems since your last upgrade. Be sure to schedule an energy audit, be proactive rather than reactive, and be educated.