Reducing Energy Use

Building owners have a number of ways to creatively address rising costs and environmental concerns. One option is to conduct an energy audit to find ways to increase efficiency. In the auditing process, energy meters collect energy usage data for a period of time, typically 30 to 90 days. After this collection period, the data is analyzed and used to identify sources of energy waste. Building owners can use this information to adapt to more efficient usage patterns. Additionally, usage data can be compared to time-of-use costing data from the local utility provider. Utilities charge more for power at peak usage times. Building owners can choose to modify their practices to reduce their electricity usage at these peak times. After a formal energy audit, many building owners choose to have energy meters permanently installed in their facility to routinely monitor and adapt their power usage practices.

“To manage your energy, you have to be diligent and monitor your energy usage. Using the monitored data to make intelligent decisions can save time and money,” states Cheryl Kennedy, member of the Cascadia Regional chapter of the US Green Building Council and product manager at Veris Industries, Portland, OR.

Additionally, a smart BAS control design can address both rising energy costs and increasing awareness of the threats to our natural resources. Studies have shown that a well-operated control system can reduce energy use by 15 to 20%, lowering the energy bill and the carbon footprint for the building.

Environmental sensors are an integral component of a smart BAS control system. Sensors provide valuable real-time information about interior conditions, enabling the best decisions regarding the use of energy with respect to the immediate needs of the building. For example, an occupied building will accumulate CO2, which can lead to drops in productivity. Typical comfortable CO2 levels in commercial spaces are approximately 600 ppm. Running the ventilation system will maintain this level, but continuously running the fans and conditioning the outside air for interior comfort are costly. Incorporating CO2 sensors into the BAS design will trigger the ventilation controls to activate only when levels are high (usually above 1000 ppm), in much the same manner as a thermostat triggers temperature controls only when they are needed. Humidity sensors work similarly to maintain comfortable interior moisture levels. The sensors also use control algorithms that use interior measurements to determine whether to draw in air from outside the building and condition it for interior comfort, or to recirculate interior air.

Temperature, humidity and CO2 level are the three most important criteria for measuring interior comfort. Inefficient operation of a BAS system with regard to comfort levels consumes excess energy, which raises the building’s utility bill and enlarges the carbon footprint. In recent years, BAS designers have been integrating the monitoring systems for all environmental comfort criteria into a single network. All data is sent to a central control system, which then makes decisions about how to balance the building’s comfort needs with energy-efficient practices. Buildings that use this integrated, whole-building approach to monitoring are known as “intelligent buildings.” (Sarah Romero, Veris Industries)