Data Acquisition: Gateway To Energy Monitoring And Efficiency Of Existing Buildings

Effective data-mining technology is a must for owner/operators who want to know where they have been and where they want to go.

By implementing a data-acquisition solution to monitor and determine energy efficiency, facilities can save money and become more sustainable. The ability to acquire and manipulate data is key to implementing a benchmarking plan that measures and verifies energy usage so that the impact of energy saving initiatives can be quantified. This capability can help existing buildings obtain the Environmental Protection Agency’s ENERGY STAR® label and new buildings earn Leadership in Energy and Environmental Design (LEED) credits through the U.S. Green Building Council.

As most readers of this publication know, ENERGY STAR is a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy designed to help building owners save money and protect the environment through energy-efficient practices. The program provides tools and resources to strategize and quantify improvements in energy performance. Its free online tools help assess performance, set goals, create and implement action plans, and evaluate progress. As shown in the accompanying figure, to calculate an Energy Star rating for existing buildings, a minimum of 12 months of utility data plus basic building information is input into a free online tool called Portfolio Manager. (See www.energystar.gov for more information.)

Even as existing building infrastructures are reviewed and opportunities to make them more energy efficient are sought, the value of developing a benchmarking plan is often overlooked. While utility bills show building owners how much power they are buying, they don’t reflect how much energy is being used. By understanding the value of benchmarking—and how an easy-to-use, economical data-acquisition tool can streamline their ability to use data—building owners can gain the insight into how to implement a proven energy monitoring and measurement solution for improving energy efficiency and earning the ENERGY STAR label.

Sample report from free Portfolio Manager tool (Source: www.energystar.gov)

In energy-efficiency terms, benchmarking [Ref.1] provides organizations with information to identify how and where they use energy and looks at factors driving that energy use. Overall, benchmarking information helps organizations zero in on the crucial metrics for assessing performance, establishing baselines and setting energy-performance goals. Relying on data-acquisition capabilities, the benchmarking process can be internal or external.

• Internal benchmarking lets organizations compare energy use at a building or group of buildings against that of other facilities within the enterprise. In turn, they’re able to use the benchmarking data to compare energy performance—identifying facilities with largest potential to save energy; following performance over time; finding best practices at specific facilities that can be duplicated; and increasing the overall understanding of how data can be analyzed.
• External benchmarking allows management and facility managers to compare a building to similar facilities. This information can then be used to evaluate energy performance in comparison to similar facilities (in similar sectors/industries, as well as over other industries). External benchmarking measures the energy performance of facilities against a national performance rating—following performance against industry or sector and finding new best practices to adjust building performance to increase energy savings and overall driving greater awareness of how to track performance. 

Benchmarking is either quantitative or qualitative in nature. Comparing actual performance measures, the quantitative process is necessary to establish an energy-management plan. These numbers are typically looked at from a historical perspective (like performance over time) or from the vantage point of how a facility matches up against similar facilities in an industry.

Steps in developing a baseline/benchmark

Acquiring the data
While metering provides the raw data for energy measurement and profiling, data collection is only the front end of the benchmarking process. Unless raw data can be exported and analyzed, it has limited practical value. Only when data has been collected and converted into useful information for developing strategies for reducing energy expenses, using energy resources more efficiently and improving operating costs does it become an asset.

A key to mining the data that is readily available from meters and input/output devices is to implement a cost-effective solution that provides the ability to collect and store historical data that is easily accessible. This makes it possible to collect and analyze data on:

• Energy use
• Peak demand
• Time-of-use metering of water, air, gas, electricity and steam (WAGES)

It also provides the potential for the measurement and verification of energy initiatives, load comparisons, threshold alarming and notification, multi-site load aggregation, real-time historical monitoring of energy consumption patterns for negotiating lower energy rates, and identifying errors in utility bills that might otherwise have gone unnoticed. 

One example of the importance of data mining with regard to determining actual savings on projects was highlighted in a review of the $3.2 billion distributed for the Department of Energy’s Energy Efficiency and conservation Block Grant Program. A recent report from the GAO concluded, “…most recipients do not measure energy savings by collecting actual data and several factors affect the reasonableness of energy-savings estimates.” [Ref. 2]

Recipients of these grants are required to complete complicated forms including providing actual energy data. However, this proved to be difficult:

“…according to some DOE officials, there have been only a few opportunities for recipients to collect actual energy-savings data because in most cases actual data are only available after a project has been completed, and recipients are just beginning to complete projects. These officials said that instead of collecting actual energy-savings data, most recipients report estimates to comply with program reporting requirements.” 

One solution
Data-acquisition tools have been developed at various cost points over the last few years. By implementing a solution with a low-cost energy meter and data-acquisition technology, the situation described by the GAO may have been avoided. 

While many companies market power-quality and energy meters with Ethernet-ready connections, such meters might prove too expensive for some projects. A wide range of energy meters at lower price points (and without direct Ethernet connectivity) are also available. Without a data-collection and storage tool, however, collecting and storing data from these meters can be a tedious, imprecise process—one that calls for personnel to check the meters regularly, in person. 

Power Xpert Gateway 200E device page

That said, there are data-acquisition products that provide an economical solution for measuring and improving energy efficiency/energy consumption in existing buildings (and the ability to do it remotely). Used with revenue-grade metering, these devices are able to acquire revenue-accurate interval data and make it available for the real-time viewing and recording of key energy values in a five-minute, fixed interval log file.

By collecting the data from individual meters, information can be viewed and analyzed via embedded Web pages. Devices with their own Web server and Web pages allow users to access information online, and drill down to the individual Web pages from connected meters. The status of all connected devices can be easily made available so that checking the health and performance of equipment is quick and easy. Not only is information easily accessible through any Web browser, enabling remote monitoring, but also there are additional features available to speed installation and lower integration costs through plug-and-play connectivity.

More specifically, it acquires and logs data from up to 64 serially communicating meters and input/output devices via INCOM and Modbus RTU connected devices in fixed five-minute intervals. Data from downstream devices is time-stamped and stored in non-volatile memory. The supported parameter values can be passed on to existing or new management software packages. Using Modbus TCP, users can view, record and monitor in their Building Management System or, using SNMP, users can view, record and monitor in their Network Management System (NMS). Using a data-collection tool’s user interface via Ethernet, collected data can be pushed or pulled via HTTP/HTTPS or any Ethernet-based building-management system via Modbus TCP or network management system via SNMPv.1. In addition, the interval log file can be exported to Microsoft® Excel® to generate a report or graph for further manipulation and recording.

A digital input module can be used to monitor water, air, gas, electric and steam (WAGES) data acquisition, logging and real-time value display. 

Additionally, free downloadable tools can provide expanded views into energy benchmarking, usage and savings. For example, they can provide users with a way to gather the key energy parameters they are concerned with and display them in a simple tabular and graph report. There are tools available that allow users to select upwards of four devices at a time and any of the interval logged data points to compare the downstream devices’ energy parameters to other energy parameters or other devices from the same time variable (day, week, month).

The bottom line
Accurate data acquisition is not an option when it comes to ongoing energy monitoring and increased usage efficiency. A modest investment in proven technology can yield substantial returns (i.e., helping building owners save energy, protect the environment and earn ENERGY STAR status). UM

References
Information on benchmarking is based on the 2008 “ENERGY STAR® Building Manual” report,  (“>http://www.energystar.gov/ia/businessEPA_BUM_CH2_Benchmarking.pdf?7987-6c6a).

United States Government Accountability Office (GAO), Report to the Congress. (2011, April). RECOVERY ACT Energy Efficiency and Conservation Block Grant Recipients Face Challenges Meeting Legislative and Program Goals and Requirements (Report No. GAO-11-379). Retrieved from http://www.gao.gov/

This information was supplied by Eaton’s Connectivity and Communications and Energy Management and Sustainability Solutions groups.