With energy accountability a more critical factor in today’s commercial real estate market, lowering a building’s energy costs has become a matter of economic necessity in all types of commercial facilities. A key element of any energy efficiency strategy is to ensure that an effective sub-metering system is in place.
In addition, Local Law 88 in New York City, part of the Greener, Greater Buildings Plan, will mandate sub-metering for large non-residential tenant spaces over 10,000 s/f by 2025, primarily as a means to get tenants involved in reducing energy usage.
Sub-metering is the internal metering and analysis of a building’s energy systems. While the utility company’s metering provides the macro-view of energy usage it is sub-metering that better manages total energy consumption, breaking apart the sum of the energy usage into its parts — by energy type, use and user.
Once the basic elements are measured through accurate sub-metering, then the total facility energy use can be better understood and more effectively managed; sub-metering establishes the quality data foundations necessary to account for overall energy use.
A recent example illustrates how an effective sub-metering strategy can benefit building owners.
UtiliVisor was retained by Sage Realty to evaluate the performance of existing submetering systems at several properties in New York City.
Sage management staff wanted to better understand the accuracy of its metering systems because many of meters were old and nearing the end of their useful life.
Utilivisor’s service engineers went out to the buildings and field tested the accuracy of each meter, installing a portable industrial grade measurement device in parallel with the existing meter.
The sub-metering analysis provided a means for Sage to reconcile the utility costs to the building and the revenue from sub-metering systems and common area charges to maximize their recovery.
The tenants also benefitted by getting a certificate of accuracy for their utility bills.
The results of the project got Sage Realty thinking about other ways to reduce operations costs through metering and to consider utiliVisor’s other suite of services to find additional energy efficiencies at its buildings’ chilled water plants.
UtiliVisor connected portable BTU and steam meters to measure efficiency (in pounds per ton) on steam turbine chillers at several different operating conditions. Data collected from the plants were brought to utiliVisor’s operations center where systems engineers were able to identify the true costs of operating each piece of equipment and identify inefficiencies compared to the manufacturer’s design.
As a result, new pump operating strategies were devised that would optimize performance.
The adjustments yielded substantial energy efficiencies.
Through the use of portable meters and its chiller expertise, utiliVisor was also able to recommend new operating strategies to save on ongoing operations costs.
The value of the savings from the chiller plant analysis enabled Sage to reap a real return on investment for metering and meter data analysis.
According to Glenn Dibiase, director of property management at Sage Realty, “The utiliVisor team met and exceeded our expectations. The savings they identified in the steam chiller plant more than offset the cost of one year of sub-metering services and meter testing. And the analysis they provided will result in continuous savings well into the future.”
Sub-metering has proven to be an effective method of energy reduction and carbon savings, especially for owners who use LEED, Energy Star or a homegrown energy improvement strategy. The real-time meter data, analysis and display support interactive energy improvement approaches.
Without real-time information, these strategies can only be validated when the data becomes data available.
With effective sub-metering, energy efficiency adjustments can be made immediately and continuously to accommodate changing conditions, resulting in lower utility bills for months to come.
Originally published on Rew-Online.com.