Understanding Energy Management Systems



"Both demand-controlled ventilation (DCV) and EMS are emerging technologies that haven't quite changed the market just yet," Fisher says. Together, however, they have the potential to do just that.

Most energy management systems will shut exhaust systems off overnight, but they lack communication both with outdoor air temperatures and with hood fans, Fisher says. This means they don't draw in cooler air from the outside instead of ramping up air conditioning. Others may control larger building and HVAC temperatures, but not cooking-hood fans.

At their simplest, DCV systems use a temperature probe in exhaust duct collars to control temperatures and fans. More sophisticated systems use infrared technology to detect when appliances are on or off, controlling hood fans accordingly. One system shoots a beam across the cooking line to detect heat and steam. A more precise unit notes temperature directly above pieces of equipment to detect not just heat and steam, but whether food has been placed on the appliance, even before the heat rises.

At least one manufacturer connects this DCV system with EMS, allowing users to monitor hood-fan technology from remote computers. This manufacturer purchased a processor from an EMS vendor to do so, Fisher notes.

EMS and the Future

In theory, energy management systems of the future should control whole buildings and more aspects of a restaurant, not just the HVAC or lighting alone, Fisher says. A system of the future might monitor those functions as well as refrigeration, water heating, hood fans, outdoor and makeup air and even equipment on-off schedules.

"I think the energy management systems of the future have to embrace demand-control ventilation, or at least communicate better with demand-control ventilation systems for them to really take off in our industry," Fisher says.

In that sense, EMS technology will be more of an interface with all facets of an operation. This was — and is — the theory behind "smart kitchens" and the NAFEM Data Protocol. But without better integration between all parts of a building and kitchen, Fisher points out, and between EMS makers and hood and equipment makers, these may remain visions of the future. "Our current goal is to continue to work with end users to get some case study testimonials and better data," Fisher says of the Food Service Technology Center's efforts. Better data might also mean potentially better rebates for such systems.

The U.S. Department of Energy has come on board to support the cause as well through an initiative with the Better Buildings Alliance. "One of their activities is to define and characterize EMS and their future for foodservice," Fisher says.

"As restaurants become more efficient, EMS becomes the first line of defense in getting rid of that sloppiness in an operation that can lead to excess energy costs," he continues. "The idea is that ultimately, these systems will become a best practice in the tightening up of operations."

BBA to Offer EMS Guidance

The Department of Energy's Better Buildings Alliance (BBA) was scheduled to release a guidance document for energy management systems on its website on October 1. The document, developed in part by the BBA's foodservice team, will help energy managers, sustainability program coordinators, restaurant owners and others invested in energy efficiencies determine if EMS is right for them, according to Rich Shandross, associate director of Navigant Consulting who heads up BBA foodservice team projects such as this.

In addition, the document will help managers determine the right type of EMS for their operations as well as evaluate vendors and gather full technical and planning information in order to install and maintain these systems. From pre-installation tips to equipment checkups and software considerations, the BBA document offers a slew of best practices to help operators navigate the potentially complicated process of selecting and building energy management systems. Still, Shandross says, the long-term potential for cutting costs and enhancing efficiency can justify the effort; some projections indicate initial savings on utility bills of up to 20 percent or more per year.