Getting the most from your building's energy management system (EMS)

Energy management systems (EMS) are advanced on-site technologies designed and proven to optimize the energy performance of large multifamily, commercial, and industrial heating systems. They use diagnostic sensors, automated controls, and monitoring mechanisms to permit timely reactions to system anomalies or changes. This exciting and innovative technology - when installed, operated, and maintained correctly - can significantly reduce energy waste in large buildings and can have a very quick payback. With all of the sophistication and automation these systems contain, in order to maximize their value and performance the property management and building staff responsible for operating and monitoring them need to be knowledgeable about working with them and about how to use the data they produce. Why are EMS' needed in a building? Conventional thermostats work well with forced air and hydronic systems that are decentralized or zoned, which allows for a quick response time of the heating system. When trying to apply these temperature controls in a centrally heated building, the response time can vary greatly. The temperature of the space may differ significantly from the desired indoor set-point while waiting for the distribution system to deliver heat. Conversely, once the heat begins to be delivered to the space, it may run longer than necessary in order to insure all spaces are more than sufficiently heated, causing the building to overheat. EMS' take into account the outdoor temperature and the heat loss characteristics of the building, and use this information to determine how much heat the building needs to maintain a comfortable indoor temperature. As these systems gather information from sensors installed throughout the building, they can anticipate how much heat the building will need and detect when the building is sufficiently heated, which prevents overheating and fuel waste. What else can an EMS do? In recent years EMS manufacturers have been upgrading their on-line monitoring tools, which have become very powerful and user friendly. From a computer or hand held device, the property manager or building operator can see the operating conditions of an entire portfolio of buildings, and be instantly alerted to any problems that arise with the boiler's operating status, system temperatures, in unit temperatures and more. An energy management system may have the capacity to integrate lighting control, metering of fuel use, or monitoring of unit-level electric use. Water leaks. Buildings heated with central steam or hot water distribution contain hundreds of gallons of water in their heating systems. Some water loss through the inefficiency of steam distribution is expected, but hot water heating distribution systems should never lose water. Boilers will have a low water cut-off and automatic water feeder combination to monitor the boiler water level and add more water if it becomes too low. How often this occurs and how much water is being added needs to be monitored. Most energy management systems have an optional water meter that can be installed, which would communicate back to the EMS the amount of water that was added to the boiler. Looking at this data over a period of time has helped building managers to diagnose water leaks - including leaks in underground tanks or distribution piping that may otherwise have gone unnoticed. Safety. The health and safety of building occupants is paramount in building operations. Domestic hot water is usually produced at the central boiler at a much higher temperature than should be distributed to the building. Utilizing a mixing valve, this hot water is mixed with cold water to reduce it to a suitable temperature. The temperature of the water being sent to the building should be monitored to prevent injury to occupants (and avoid fines). An EMS can log this information, display the temperature of the water leaving the mixing valve, and send email or text alerts to building management when temperatures are outside the acceptable range. This information can be used to optimize the operation of the system, by adjusting the mixing valve control to change the temperature of hot water being sent to the apartments. Depending on the system, after receiving an alert, the manager can either remotely adjust the hot water set point or contact the on-site building operator to make the adjustment. EMS' can be very powerful tools for building owners and managers to observe and operate their buildings. With brief but regular checks on the status of the building, operators can catch various issues before they become serious problems, and save greatly on their fuel bills by simply removing the waste and overheating. In the end, this makes a more comfortable living environment for all residents. Adam Romano is director of training operations at the Association for Energy Affordability, Bronx, N.Y.