Distributed Energy Magazine

Energy Audits: The Missing Value

Continuous energy audits for smart buildings

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Credit: iStock/NicoElNino
It is estimated by the US Department of Energy (DOE) that 30% of energy used in commercial buildings is wasted. While unnecessary power consumption represents one aspect of wasted energy, inefficient use represents another. To optimize energy use, buildings have historically used Building Automation Systems (BAS) or Building Management Systems (BMS) that provide monitoring and control of a building’s HVAC, lighting, and other systems that consume power.

More recent entries into the market include “smart building” solutions that look to further the capabilities of the typical BAS system by using the information available from them to provide Artificial Intelligence (AI). This AI will use the raw data available to run an analysis on all variables to help identify sources of inefficient operation.

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Credit: CircuitMeter Inc.TopAdvanced submetering measures electrical parameters in real timeBottomDetailed demand analysis through real-time energy analytics
Credit: CircuitMeter Inc.
Top: Advanced submetering measures electrical parameters in real time.
Bottom: Detailed demand analysis through real-time energy analytics

Many of the inefficiencies identified can be attributed to operator error by those responsible for the use (or misuse) of the BAS system. These errors could include issues such as poor scheduling, set-point overrides on analog control loops, or digital points being set into a fixed or bypass mode which disable control system logic. While all of those things may make the occupant of the building happy, they are not very good for the budget.

Additional issues are often tied to mechanical failures which, while wasting power, also lead to occupant comfort issues. Leaky dampers, valves, and faulty motors are just a few. More efficient indoor environments are correlated with improved comfort, productivity, and well-being. These impacts can be significant. According to a recent joint study by The Pembina Institute and The Atmospheric Fund, symptoms of respiratory, allergy, and rheumatism conditions can possibly be reduced through more efficient ventilation systems and air tightness, both in new build and retrofits. In fact, several studies found that health benefits could represent up to 75% of the overall benefits of energy efficiency retrofits.

The mechanical system, however, by design, can overcome many issues (think: a leaking cooling coil in which the BAS simply opens the heating valve further to compensate for the additional cooling load).

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Most of the new smart building systems are cloud-based and designed to optimize not only individual buildings but portfolios of buildings. Using these systems, an owner can ensure that they are operating each facility efficiently. Furthermore, comparisons across buildings can lead to the sharing of best practices within an organization.

The typical effort to enable smart building technology utilizes integration into the existing control systems within a facility. This almost always includes an integration into the building management system but may also include integration into lighting, people-moving, and access control systems to provide a more holistic view into facility operations. While these sources of information are all valuable, there is one critical piece missing.

What Is This Missing Value?
In most commercial buildings, electrical data is measured at a single point—the point at which the electrical power enters the building. Compounding the fact that this is a single point of data, many times this data is only available from the utility, or only available at the point of billing. So, if an energy manager wants to have a real sense of how buildings are performing they have very little to go on. As the adage goes, “You can’t control what you can’t measure.”

Changing Times
In the world of smart buildings, electrical metering technology is finally catching up to the curve. By using advanced technology and designing a metering solution from the ground up, a new generation of metering suppliers has broken down barriers that prevented granular real-time electrical data from being a cost-effective option.

What’s It Worth?
While we know we can’t eliminate all waste, the DOE believes we can tackle 20%. In fact, the Building Technologies Office of the DOE is targeting a 20% reduction in energy use in commercial buildings by the year 2020. More ambitious savings are targeted for 2030.

So how do we squeeze out another 30% in efficiency given all the steps that we have already taken? Considering that the vast portion of our energy consumption is in the form of electricity, we will look there. This invisible and mostly misunderstood consumable is the only one we don’t measure throughout our buildings. It the only one that is allowed to leak freely while we all move around our facilities completely unaware.

So, while more and more building owners look for reliable data that can be used in any optimization plan, detailed and granular electrical data is the missing value most needed.

Why Is Metering Important?
Advanced submetering technology supports all of these capabilities. As a data-gathering tool for a facility’s energy-using systems, submeters can improve an organization’s bottom-line by placing greater visibility on its energy footprint.

Granular metering provides a highly reliable, low-maintenance solution; a solution whose data can reliably be used year after year or moment after moment with little concern about data drift. Data that can be used to see in real time the exact electrical characteristics of every asset and circuit in your building; the current draw from your chillers, the power factor of your pumps, the reactive and resistive power of your lighting, etc.

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Credit: CircuitMeter Inc.
Real-time energy monitoring from an enterprise level drilled down to an individual piece of equipment

 

While Having Real-time Data Is Great, It’s What You Do With That Data That Counts
Again, the answer lies in emerging technology. Using powerful hosted platform solutions, leading edge companies are emerging in this field. These forward-thinking companies can analyze the real-time electrical data and provide powerful energy insight valuable to all levels of an organization. The analytics, artificial intelligence, and asset metrics are provided to achieve greater energy efficiency. As if to put a bit of icing on the cake, the same tools support predictive maintenance and boost operational efficiency as well.

Continuous Energy Audit
Energy audits are generally performed by outside service companies with temporary meters to measure a sample of a facility’s overall energy use. This snapshot of energy use is incomplete and generates an inaccurate impression of energy use. In turn, this information is used to populate energy use models. The models are then used to provide guidance to energy, operations, and maintenance professionals. Finally, professionals use a combination of scheduled maintenance, capital budgeting, and periodic inspection techniques to keep a facility and its equipment operating as efficiently and reliably as possible.

This is the current state of the industry. It is inefficient and to a degree, ineffective. Even buildings that go through a re-commissioning exercise are documented to experience “energy drift” within 18 months.

A building or facility can still go through an initial exercise to identify all waste, but advanced submeter technology coupled with real-time communications and data analytics is providing a highly reliable “continuous energy audit” that is now cost effective to implement.

As an example, equipment that is operating with a low power factor, or with higher energy consumption than benchmarked, can be identified and flagged for maintenance or replacement. With this level of energy analytics, significant cost savings can be achieved by reducing operating costs. It can greatly enhance the potential that comes from traditional upgrades of lighting, motors, chillers, and other systems. A “continuous energy audit” can identify energy drift where it happens, when it happens, and minimize the degree to which building efficiency declines with time from initial commissioning. These losses in efficiency can be as much as 20% over the first two years. Some of the causes of this degradation can include:

  • temperature and time overrides by occupants or operators;
  • improper control system programming;
  • seasonal changes that disrupt mechanical equipment operation; and
  • failures of temperature sensors, relays, filters, or controls.

Tracking Changes in Power Quality
The ability to continuously monitor every circuit in real time establishes, amongst other benefits, a power quality baseline. The advantages of this benefit are very clear: if energy use or power quality parameters change, the advanced energy monitoring system will report and notify the end-user of the changes. The cause of the change can be identified immediately and corrective actions can be implemented. Further, the historical data is available to pinpoint exact causes of the electrical consumption spike or power quality decline. With user-friendly point and click analytics with common terminology, end-users can perform analytics confidently and seek the appropriate help for corrective measures.

Advanced submetering and real-time energy analytics can record the energy signatures for performance, runtime, and operation cycle. With these benchmarks, advanced systems can detect variances on every piece of equipment and notify maintenance before a failure occurs. Using the system analytics, the contributing factors for spikes in consumption or poor power factor conditions were easily identified. Sharing this information with stakeholders in building operations can lead to changes in operating procedures and improvements in facility management.

What Next?
Submetering has come a long way since the first electronic meters were introduced. The information gap has been bridged by easily connecting with building automation systems and IT-based financial and energy management systems, making energy visible to all facility owners and operators. With technology breakthroughs that address cost, complexity, reliability of data, and visibility issues, there now exists a cost-effective solution to meet the 20% energy reduction targets by the year 2020. With capabilities for a continuous energy audit in real time, facility managers now have the tools available to turn their facilities into smart buildings, which not only reduce energy waste but also improve occupant comfort and well-being. We’re just scratching the surface. BE_bug_web

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