Originally published in Interiors & Sources

05/02/2011

The Best Tool in an FM’s Arsenal

With a measurement and verification plan, knowledge is power

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  • /Portals/1/images/Magazines/0511/Measurement_and_Verification_1.jpg

    Comparing weeks or months of daily data will help you gain some short-term perspective. For example, a string of unseasonably warm days would likely lead to more usage until the temperature drops.
    PHOTO COURTESY OF airadvice
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    Viewing your usage over the course of a day will help identify spikes and dips that don’t look right.
    PHOTO COURTESY OF airadvice
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  • /Portals/1/images/Magazines/0511/Measurement_and_Verification_5.jpg

    Some software can track cost savings. The dip in the graph marks the start of energy cuts; from there, savings rise over the next few weeks.
    PHOTO COURTESY OF airadvice
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Utility bills never tell the whole story.

You can wait until the statement comes from the energy provider. You can compare this month's bill with last month's, see how much more power your building consumed, and try to remember how many times people forgot to turn off the lights at their workstations.

Or you can see that information minute by minute for any location in the building. It all starts with a solid plan for measurement and verification (M&V) of your energy consumption and efficiency.

Get in the Game
Before you start putting meters everywhere, decide what you're trying to achieve. Do you want to measure the impact of one project, such as a lighting retrofit, or are you taking a whole-building approach to energy efficiency? Determining the scope of the project will dictate how you structure your measurement and verification plan.

"If you can't measure it, you can't really know how you're doing," says Paul Torcellini, principal group manager for commercial buildings research at the National Renewable Energy Laboratory (NREL). "If you want to know if your building is energy efficient, or even what it's doing, you need to have some way of knowing you're succeeding."

To start, Torcellini says, decide what questions you want your M&V analysis to answer.

"If your only question is 'What is the energy consumption of my building?', then your metering plan could be as simple as taking the monthly data from the utility bills every month, aggregating it, and reporting what your energy consumption was," Torcellini says. "If you want to know 'Why is our energy use high?', then you have to start submetering in terms of lighting, HVAC, and plug loads so you can say 'Now I know where my consumption is. Here's where it's going.' Then I can have action to say how to make that change."

Once you've chosen what questions to answer, you'll have to determine the methods you'll use to find the solutions. If electricity consumption is important, you'll probably start considering temperature or humidity sensors or smart meters to measure electricity use by floor or department.

Some softer questions might complement your energy analysis – for example, in addition to asking why your building consumes so much energy, you might also want to measure occupant comfort with a survey. Most plans will also require other basic data, such as occupancy and the physical size of your building, to place your usage in context.

Easy Targets for Energy Savings

  • Conduct a walkthrough to spot obvious fixes, like turning off lights near windows
  • Replace or repair inefficient or malfunctioning equipment
  • Make sure building controls are programmed properly
  • Encourage behavior modification – e.g. ask occupants to turn off lights when they leave
  • Power down building systems that don't need to run at night or during weekends
  • Track when people are actually in the building outside normal working hours and scale back HVAC and other systems accordingly
  • Mandate energy-saving settings on computers

Whichever path you choose, make sure you know exactly how you'll arrive at the answer to your question, from the hardware you need to install to how to interpret its measurements. Creating a formal plan is vital for your ability to track changes and judge the success of your energy-saving projects.

"This is most important when the cost of an M&V project is significant," says Tim Kensok, vice president of market development for M&V software developer AirAdvice.

The cost varies widely depending on the size of the building, how many utilities you need to monitor, the methods you choose, and other factors. However, the cost can be significant, so it pays to get a handle on your budget and the possible costs early in the process to avoid unpleasant surprises later.

Build Your Baseline Data
With your basic plan in place, start gathering baseline data on your building's energy consumption. Baseline measurements are vital – without them, you'll never know whether your efficiency improvements are working like they should be. Look back at your initial plan – you should have already identified how you'll answer those questions, from monitoring plug loads to circulating employee surveys. Now it's time to put those plans in action.

"There are a lot of people putting in metering who don't know what they're going to do with it at the end of the day," says Torcellini. "It may get you more detail, but at least know that you're putting it in because you're going to need that detail. Sometimes, corporations set goals and they say 'We need to reduce our carbon footprint.' Then that comes down to 'What kind of vehicle miles do we have? How much trash are we generating? How much water or energy are we using?' Once you have that baseline, then you can say 'Let's reduce it by a couple percent every year.'"

You'll also need a dependable way to track this data. The EPA's Portfolio Manager keeps track of your building's data in detail, from carbon dioxide emissions to energy intensity. You can also add data from your facility's utility bills to round out the picture of your building's energy usage.

For an extra level of control, install energy tracking or benchmarking software to interact with your meters and track your other data – some programs can even interface with Portfolio Manager. Other applications can make energy-cutting suggestions, continually measure and verify your usage, and alert you if it finds a sudden spike or dip in consumption that could indicate a serious problem.

Being able to monitor hard data (like energy usage) in the smallest increments possible and as close to real time as you can get not only gives you the clearest picture of your facility's usage trends, but also lets you pinpoint exactly when spikes happen to narrow down the possible causes.

"You might go back and say 'What I want is a dashboard that tells me every second of the day how much energy I'm currently using, how much I used yesterday, and how I'm comparing yesterday to today,'" Torcellini says. "That's something you can implement very quickly. Ultimately, you want to get to the point that the feedback is as quick as possible and people feel like they made a difference by taking action. Most people have no idea how much energy the building consumes, but they're an important part of the energy pie."

Make the Cut
Once you have a full set of baseline data to compare your later measurements with, it's time to put your plan into action. After you fix any hidden leaks and inefficiencies you found, tightening up the building's operations is "by far the easiest place to start," according to Kensok:

1. Match your operations to the occupants' needs. "It sounds simple, but it's not at all uncommon to find pretty gross discrepancies between when people are in the building and when building operators think they are," Kensok says. Focusing on turning off all non-essential building systems when the building is empty should provide a good basis for savings.

2. Tweak how you meet standard needs. Even if occupants sometimes come in on the weekend, you still may be able to scale back building systems then. "Maybe there's a tenant who says 'We have people who come in on weekends a lot, so we need to make sure the lights are on and the air conditioning is running every weekend,'" Kensok says. "In reality, there's only a small number of people, or on some weekends no people come in. A lot of times, there's nobody coming in, but you've spent thousands of dollars setting it up."

3. Fine-tune operations further without impacting tenant comfort. For example, in summer, the air conditioning in an office building comes on before tenants arrive. Change the settings so the air conditioning kicks in a little later, but still cools down adequately before anyone has arrived, and you'll save energy without tenants even noticing. "If we look at the building in terms of the temperature profile, it's not at all uncommon that the building responds much more quickly than the operators think it does," Kensok adds.

Involving the other occupants of the building is key. According to the GSA, 50% of occupant spaces are unoccupied in a typical office building during the work day. This presents a prime opportunity to drive your energy consumption lower.

"Say 'If you go out to lunch, did you turn your lights off? Did you turn your computer off? Do you need a fancy plug strip that helps you do that? Is your computer set up with ENERGY STAR settings?'" Torcellini says. "Those are things any user can do."

After enlisting occupant support and implementing any additional efficiency upgrades, monitor your ongoing measurements – data from your meters, or the latest version of your regular employee survey – and check them against your baseline measurements to verify that your improvements performed as expected. If not, why not? Use these comparisons to diagnose what went wrong – perhaps you've developed a leak that's letting in extra outside air and overworking the chiller. Find the hidden energy escape routes, like malfunctioning or inefficient equipment, and fix them.

Like Aaron Derr, an engineer with contractor J.E. Shekell, you may find that a building system wasn't installed correctly.

"We were able to see that the system wasn't properly setting back on weekends. The HVAC system was still running the blowers on the weekends when the building was unoccupied," Derr says. "We thought the programming was in there to do that, but it turned out the system didn't accept it. The key is to try to get things fixed immediately and not have to wait until you have a couple months of utility data to see if you're doing something right or wrong."

After the Initial Implementation
Hitting your goal isn't the end of the road – keep an eye on your measurements regularly. M&V isn't a one-time project where you make efficiency improvements, check to see if they worked, and leave it at that. Done right, M&V is a constant process of watching the incoming data so you can catch problems before they impact your facility too much. Some software packages will generate reports with graphs so you can see at a glance whether unexpected spikes have struck and focus your efforts accordingly.

Keeping an eye on M&V data doesn't need to require a huge time investment or staff-wide training either, Derr says. Persistence is the key to spotting molehills before they become mountains.

"Anybody who's familiar with their facility and their equipment could be trained fairly easily on what to look for," Derr adds. "I'm using this as a tool to get this system set up, and then my intent is to step away, turn this over to the facility manager, and let them take it and run with it."

Janelle Penny is associate editor of BUILDINGS.

 

 
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