Energy­ Management Systems: Putting You in Control


©2015 NHSaves

 

Key Points:

  • Energy ­management systems (EMS) can reduce energy consumption by 10 to 30 percent.
  • EMS designs range from single ­point control devices to complex, facility wide systems.
  • An EMS can control lighting and HVAC systems, as well as manufacturing process equipment.

Energy conservation is a team effort, but getting everyone to cooperate can be difficult. Lights are left on in unoccupied rooms, unused equipment continues to run or staff members fail to follow guidelines regarding efficient operation. Oversights such as these waste energy, which can cost your organization a substantial amount of money. Energy management systems (EMS) help facilities become more efficient by putting managers in control. From a single point, you can measure, monitor and regulate energy ­using systems. A properly installed and maintained EMS can result in energy savings of 10 to 30 percent.

How an EMS saves energy

An EMS reduces energy use in buildings by monitoring conditions and controlling energy ­consuming equipment. Frequently used for building loads such as lighting and space conditioning, an EMS is versatile enough to provide energy savings in process operations in manufacturing facilities. Control functions include everything from basic stop/start functions to more complex, chiller optimization routines. Facility managers can use an EMS to track building system operations, perform diagnostics and optimize performance, saving energy and reducing labor costs. EMS systems can typically interface with existing building controls.

An EMS can take various forms, from a single­ point control device to a complex system which manages energy use across an entire facility. Cross ­functional EMS systems provide the greatest potential to maximize energy and cost savings. Simple systems include actuators that switch or change loads according to signals from local controllers. Systems that are more sophisticated add sensors or monitoring points, field termination panels, modems, communication links and central computers. Centralized controls allow facility engineers to interface with remote equipment to diagnose problems.

System components

Systems vary by the type of facility and the level of control needed. Commonly used energy­ management devices include:

  • Timers turn lighting and equipment on and off according to a schedule. Small loads are switched directly, while large loads are controlled indirectly with relays.
  • Occupancy sensors detect whether people are present by sensing heat (infrared), motion (ultrasonic) or sound. 
  • Programmable thermostats allow for automated building temperature adjustments according to operating schedules and seasonal changes. 
  • Photocells regulate light levels, dimming or increasing lights according to the amount of available daylight. Combined with timers, they can be used to program outdoor lighting as well.
  • Program logic controls (PLCs) use sensors to operate process equipment in manufacturing environments for maximum energy efficiency.

Implementing an EMS

Energy­ management devices are great energy­ saving tools, but they are not effective in every situation. To maximize savings—and your return on investment—plan carefully before installing a control device. Carefully examine your facility, energy use patterns and occupancy needs. For example, lighting control may not be useful for a conference room where meetings are rarely held. Individual devices are relatively inexpensive, but installing a complex management system will require a significant investment of time and money; apply it where it will be most effective.

A new system will not necessarily interface properly with existing controllers and other remaining components. Use caution when buying proprietary systems, look for products with an open protocol.

Optimize performance through system maintenance

Like any device, EMS components require attention to function properly. The following operation and maintenance tips will maximize EMS performance and your energy savings:

  • Calibrate and check sensors on a regular basis. Failed sensors and false readings can waste a considerable 

    amount of energy.

  • Protect energy­control devices from power quality problems with surge suppressors or uninterruptible power supplies (UPSs).

  • Use battery backups for timers and other scheduling devices. Power outages can disrupt energy management settings and reduce system effectiveness.

  • For safety, post signs indicating control devices and install disconnect switches near equipment operated by automated controls.

  • Train key employees on the overall design intent and the proper operation of the EMS system.

Although they require time and effort to properly implement and maintain, an EMS puts you in control of your energy use. It can reduce your operating costs substantially as well.

 

Chris Chilek