U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office
Assessing and Reducing Plug and Process Loads in Commercial Office and Retail Buildings Webinar (text version)
This webinar presented strategies to help reduce plug and process loads (PPLs) for commercial offices and large retail buildings. Aimed at building owners, operators, occupants, and facility managers, this webinar outlined recent National Renewable Energy Laboratory (NREL) research and publications designed to help reduce PPL energy consumption.
Below is the text version of "Assessing and Reducing Plug and Process Loads in Commercial Office and Retail Buildings," originally presented on November 21, 2011. In addition to this text version of the audio, you can view the presentation slides and a recording of the webinar (WMV 17 MB).
Welcome and thank you for standing by. At this time all parties are placed on listen only mode. Today's conference is being recorded. If you have any objections, please disconnect at this time. Now I would like to introduce your speaker, Ms. Michelle Resnick. You may begin.
Thank you, Bobby. My name is Michelle Resnick and I'd like to welcome you to today's webinar titled Assessing and Reducing Plug and Process Loads in Commercial Office and Retail Buildings. This webinar is presented by the Commercial Building Energy Alliances Program at the U.S. Department of Energy.
We're excited to have with us today a few experts who developed publications designed to help building owners, occupants, and facility managers reduce plug and process load energy consumption. But before we start, I have some housekeeping items to cover. First, I want to mention that everyone today is in listen only mode. We will have a Q&A session at the end of the presentation. You can participate and ask your questions any time throughout the webinar by clicking on the Q&A link at the top bar of your screen, type in the question in the box, and clicking Ask. Please be sure to click Ask and not the symbol of the raised hand.
Our speakers will address as many questions as time allows after the presentation and we encourage you to submit questions throughout as you see fit. And now for a little bit about our speakers today. Today we have with us Michael Sheppy and Chad Lobato. Michael and Chad are both research engineers in the Commercial Buildings Group with a specialty in plug loads, data centers, and measurement and verification technologies.
Our speakers today will outline strategies to reduce plug and process loads for commercial offices and large retain buildings. And with that, I'll turn the presentation over to Michael.
Thank you, Michelle. So without further ado, let's get started. My name is Michael Sheppy and I'm presenting with my colleague, Chad Lobato. We're both research engineers here in the Commercial Buildings Group as Michelle mentioned. So I'll go ahead and move onto slide two.
Let's start with a few key questions and I'd like you guys to all keep in mind these questions during the presentation. And by the end of this presentation you should be able to answer all three questions. The first question is, what are plug and process loads? And second question is, why are plug loads so hard to control? And the third is, how can I use NREL guides to reduce plug loads in my building? And we'll specifically talk about the guides that Chad and I have developed and how you can use them to save energy in your building.
First of all, let's start off with some definitions and go over the problem in general. So by definition plug loads are building loads that are unrelated to general lighting, heating, ventilation, cooling, and water heating. They also typically don't provide comfort to the occupants. Below there's a pie chart here that shows total primary energy consumption of plug loads. So the impact of commercial plug loads is about 5 percent of U.S. primary energy according to the DOE Buildings Energy Data Book in 2010. And you could see that that's a significant portion of primary energy use and so there are some opportunities here to save some energy nationwide.
Next we'll talk about some plug load problems and challenges with addressing plug and process loads. We'll go over these in more detail, but in general here are some high level ones. In general, plug and process loads aren't viewed as an integral building system. No single decision maker specifies all efficiency strategies. So, for example, you'll have your IT folks specify laptops while in your coffee bar or your cafeteria you'll have a contractor or a vendor specifying those commercial cooking equipment plug loads. Lastly, plug loads are not addressed by building codes, typically not addressed by building codes.
Some more definitions here and we'll be using these terms throughout this presentation. The first one is the definition of in use. So in use is when you have a plug load that's plugged in and being used. Pretty simple definition. The second is parasitic load. Parasitic load is any time you have a plug load that's plugged in, powered on, and not being used. That can be during occupied hours or during unoccupied hours. If it's not being used, it's a parasitic load. And the final term I want to go over is de-energize. De-energize is when you physically unplug something from the wall. So it literally has no power being supplied to it.
So you've all joined in today to listen to us talk and we wanted to give you kind of a reason for you to listen to us. You're probably wondering, "Well, how did they come across these strategies and why are they the experts?" So we wanted to give you a brief look at what we've learned and where we've learned it from. So for office plug and process loads, we now have at NREL our new Research Support Facility and the design of this building really sparked a lot of in-depth research into office plug load research.
The reason for that is the Research Support Facility has net zero energy goals. With our baseline plug loads, the plug loads would have eaten up the entire energy budget for the entire building. So in order to meet the energy goals of the building, we had to reduce our plug and process loads by 50 percent. Later on we'll go into some of the strategies that we've uncovered during our research, but we won't go into that here.
Next is retail plug loads. So through the Commercial Building Partnerships project that we've worked on and various plug load audits, we've learned a lot about plug loads in retail buildings. We've also done several in-depth long term plug load metering studies in several large retail buildings and that's helped us arrive at the strategies we're presenting to you now.
So you all are probably wondering what some examples of plug loads in office buildings are and for the most part they're pretty commonsense and simple. You can see the list on the left. We've included here an example of what our workstations look like at NREL. It's in the upper right hand corner. You can see we have approximately 18 Watt LED backlit LCD monitors. We have power management surge protectors that help control plug loads at the workstation space. We have a 6 wall LED task lights, a 30 watt laptop computer and a 2 watt Voice Over IP phone. And so this is an example of a low-energy workstation.
In the lower right hand corner you can see our baseline energy use compared to our plug load energy use in the Research Support Facility. And just take a second to look at this; you can see the variety of plug loads categories that you run into in an office building, it's a good example of all the different categories that you might find. Also, you can see that in order to meet the energy goals we had to reduce the consumption by roughly 45 percent which is a huge savings.
Next we'll move onto examples of plug loads in retail buildings. And plug loads in retail buildings are really a lot different than what you'd find in an office building. For one, common sense will tell you that retailers sell a lot of electronics and a lot of retailers choose to power on their electronics when they sell them and to have things like movies and music playing on television and on radios. The bar chart to the right is the quantity of plug loads that we found in one retail building. So it's about 450 plug loads total. And just take a look at the categories here, of all the different plug loads that there are. So from this you can see that plug loads are very high in quantity in retail typically, depending on the retail store. And also they're very diverse which makes them difficult to control.
And we'll get more into that as the presentation goes on. Next we want to talk about things that affect the energy use of plug loads. And while I'm talking, just as a fun exercise, look at this picture and see if you could – that might be present in this retail store. So there are a number of variables that are manufacture dependent such as in-use power draw, parasitic power draw, a built-in low power state, built in on/off functionality, built in battery backup, and so on. And in general plug load devices, they come from the manufacturer with these characteristics built in. And all these variables, they do affect the energy use, but typically the end user doesn't have much control over these variables.
Second there are use dependent variables that affect plug loads such as location. So, for example, a television or a LCD flat screen monitor in the electronics department of a store will be operated totally different than in an office space where somebody's using the flat screen monitor as their computer monitor. Second is a lot of plug load behavior or plug loads energy use is based on user behavior. It's user behavior driven. And so everybody has different use schedules and use patterns and that affects the energy use.
Fourth point is implementation. So, for example, again I'll use the example of a television. So if you implement the television as a security monitor or you implement it in the electronics selection or in an office space, they'll be used completely different in those three cases. So that definitely will affect the energy use. And the fifth point is device control. So this can be driven by the user, how well the user turns off the device at night when they go home for the night or whether or not the device has built-in on/off functionality and if those low-power functions are enabled on the device. These are all device control variables that will affect the plug loads energy consumption.
Next, I want to talk about why are plug loads so hard to control. And you may see that in the slides that a lot of the variables that affect plug load energy use are the same things that make plug loads very hard to control. So again, you see here that built-in low power functionality and so it can be inconsistent, unreliable or not included. Different plug loads have different voltage and amperage requirements so they may have different plugs. So if you have a off-the-shelf power strip that's meant to control 120 volt plugs, that's not appropriate for your 480 volt, 3-phase plug. And so that makes the plug load difficult to control.
The third bullet point is power cycling limitations. So, for example, you take your desktop computer at home or in your office, when you want to power it off, you don't just unplug it from the wall, you have to go through a proper shutdown sequence or else you can damage your desktop computer or lose data. Whereas something like a task light at a desk, that can just be hard powered off and de-energized from the wall just by unplugging the plug and it won't damage the equipment at all.
The time for the device to be ready to use from an off state is one of the hardest aspects of controlling plug loads to address. So, for example, in the RSF, we have a coffee kiosk and they have an espresso machine and they have to come about 30 minutes early to allow the boiler to warm up and be hot enough to make coffee or espresso when the first customer arrives. Now it wouldn't be appropriate to put the espresso machine on a timer and have it turn on right when everybody starts trying to buy espresso at the coffee kiosk. So that adds some complexity to controlling plug loads.
And lastly device functions. So many plug loads such as fire alarms and PA systems, they provide health and safety to the occupants and they can't necessarily be shut down. So that's an extra obstacle that we face and when you're trying to procure these devices you need to look for the most efficient option available and it may not always be possible to control them. More on why are plug loads so hard to control. There's use dependent factor. So as we stated before, a given device may be used differently depending on its location. And a lot of plug load energy consumption is driven by the behavior of users and their use patterns, their schedules, their work schedules, things like that.
And, as I mentioned before, implementation. So we saw that there were 450 plug loads in that one retail building and so plug loads are often present in large numbers. They're very diverse and, for example, at some retail stores they have a wall of TVs that play ads and things like that and those can directly generate revenue. Another example is a vending machine. Vending machines, they directly generate revenue. And so that makes them difficult to control. And often there's opposition to controlling them because there's a fear of reducing revenues.
Okay, so at this point in the presentation we've given you a general overview of plug loads, what they are and why they're hard to control. Now we kind of want to introduce you to plug loads guides that we've developed and they're meant to be how-to brochures. We've developed two plug loads guides. One deals with retail buildings and the other office buildings. You can follow the links presented here to down these guides. We'll be updating these shortly with revised versions that provide additional strategies and useful detail so keep a lookout for that.
So in general what do these guides include? Well, they include a 10-step process for evaluating plug and process loads and we'll go through that in this presentation. They provide recommendations based on space type and equipment type. And also at the end of both these documents, there's a worksheet and it basically serves as plug loads savings calculator which you can use to get a snapshot of what the plug loads in your building might look like. And it'll also highlight the opportunities or the biggest opportunities for savings, basically the low hanging fruit.
Okay, so we've introduced the guides to you and, as I mentioned, the first part of the guide is a 10-step process to address and reduce plug loads. And this is applicable to both retail and office buildings. Step 1 in our process is establishing a plug load champion. So what is a plug load champion? We define it as a person that initiates and helps implement plug load strategies. And when our building, the Research Support Facility, was being built, my colleague, Chad Lobato, he's also presenting today, he was basically the plug load champion. So that was the first step in us addressing plug loads in our new office building.
The skills needed of a plug load champion, they need to have a basic understanding of energy efficiency opportunities and also plug load design strategies. And we'll go into those in more detail later on. They also need the ability to apply cost justifications so that means developing a business model and proving how certain plug load strategies will save money with a given return on investment and a good payback period. They also need to be able to critically evaluate operations, institutional policies, and procurement processes because all of these basically factor into the total plug load energy use of a building.
Step 2 is benchmarking current equipment and operations. And this is a very important step and I'll explain why. So this step, in general, what you do is you identify and inventory, your plug, and process loads in your existing building or before a retrofit or before new construction, whatever your case might be. This step helps you establish a baseline for what your current equipment is and how you operate it. It also, as part of this, it gives you a basis of comparison that allows you to use your business model to justify the cost of these strategies. It'll help you understand when equipment is used and identify strategies that will yield the largest savings.
So let's go into a little bit more detail about this benchmarking step. The first step is performing a walkthrough and developing a metering plan. Now if in your situation you manage a portfolio of buildings, then really you only need to do this for a representative building and you can extrapolate this benchmark across all of your buildings so that will save time and money. You don't need to do this for every single building, want to emphasize that.
So during the walkthrough, the champion will gain an understanding of use patterns, also the plug load champion needs to inventory the plug loads and make special note of the types and quantity of plug loads that are in the building. As part of this inventory process they need to identify the common pieces of equipment and also the unique pieces of equipment. So in an office building a common piece of equipment would be something like a laptop or a desktop computer whereas the unique pieces of equipment might be something like an ATM or a treadmill or an espresso machine.
Another important part of this step is to work with building occupants basically. So in a retail store of course you don't want to be talking to customers, you want to be talking to store manager and employees and figure out how they use their pieces of equipment and try to get an understanding of why they use it and how it helps them to achieve what they've been tasked to do as part of their jobs. Another important step, as we mentioned before, is determine whether the plug load is critical to health, safety, or business operations. And if it, then there's gonna be some special considerations that have to be made to come up with a more efficient strategy for those types of loads.
Lastly is to develop a metering plan. So in your building, if you find a bunch of common equipment, say laptops, in the Research Support Facility we have around 1,000 laptops, you really only need to monitor two or three laptops and maybe choose users in different departments so you can get kind of an idea of how laptops are used in different areas of the building. And as much as possible you should try to meter all unique plug loads. So those are the ATMs, those are the gym equipment, the espresso machine, the ice machines, whatever you may have in your building that's low quantity, but may potentially have a high load.
Step 2B is a plug load meter and we've put some general guidelines here, but by no means are they the only things you should look for when you're trying to find a plug load meter. These are our general recommendations. So in our opinion the meter should have the ability to measure and log one week of electrical power. You should be able to have a sampling interval of as fast as 30 seconds. Faster is fine, but we found that 30 second sampling intervals gives us a good resolution in the data. And your plug load meter needs to be designed for the type of circuits to be metered. For example, the 120 volt, 15 amp, 60 hertz circuit.
Also, as you remember, we talked about how variable plug loads are, what a variety of plug loads you will find. So some plug loads may have a load close to 0 watts while others will have a load well over 1 kilowatt and so your meter needs to be able to accurately meter loads of 0 to 1,800 watts. It's nice to have an external display that shows you that the meter is functioning properly and it'll tell you things like how long it's been logging and how many watt hours it's logged, things like that.
Another important feature is for the meter to have an internal clock that assigns a timestamp to each data point. And this basically makes it much easier to meter the plug loads. You don't have to write down the time that you meter started logging data. It just automatically assigns a timestamp to each data point. And lastly, when you're working in any commercial building it's normally a requirement for the meter to have a UL listing so that's one important thing to look out for.
Step 2C is metering the plug loads. So once you've selected your plug load meter, it's time to meter the plug loads that you've selected as part of your metering plan. First, you need to determine whether the plug load can be energized. So some things, like we've said before, fire alarms and PA systems that are critical to health and safety, perhaps those can't be unplugged and maybe you need to pursue other ways to finding how much energy they use. You could do that through contacting manufacturers and looking at spec sheets, things like that.
Step 2; determine whether installing a meter will interrupt business operations. So in our experience in retail stores, we had to wait until a cash register was closed before we could install a meter on it and for obvious reasons we don't want to interrupt their normal business operations and impact the customer experience at all. Basically we left untouched and not mess that up. Step 3, and this is one that most people will run into when they're doing a plug load metering study, is you need to inform users that the metering effort is not to monitor their personal activities. So when you're monitoring things like a computer you can tell when the computer's turned on, when it's turned off, when it's in a lower power state than when it's in an active state. And you need to tell the people, for example, computer user that we're not studying their use, their work schedule or anything like that. We're just out to study the energy use of the computer and so it's important to keep users anonymous and things like that to protect their privacy basically.
Step 4 is to set up the meter to measure electrical power so that's selecting your sampling interval and things like that. And then we move onto installing the plug load meter. So you power down and unplug the device to be metered, plug the device to be metered into the meter and plug that meter into an outlet. Clear the meter's memory and go through any other initial setup such as setting maybe the date and time. Then you want to power on the device to be metered and meter the device for one typical work week. And monitoring it for a work week we found is probably the minimum that you want to monitor a plug load for. More is great, but if you're limited then you can stick to a work week because that allows you to see what the energy consumption is during the weekends and during unoccupied hours and during lunch time and during peak business hours, things like that.
Step 10; once you've done the metering for a week or more, you can calculate the average load during occupied and unoccupied hours and that will help you basically to identify the largest plug load energy hogs, so to speak, and kind of focus your money or whatever, your strategies towards the energy hogs.
Okay, so you've metered your plug loads now and we wanted to provide you with some example results. Once you have your meter data, you'll want to analyze the results. Now you don't always have to use a plug load meter. In this case, this is for a retail store and we used submetering to meter the plug loads in the store. And an interesting finding was that during unoccupied hours, their plug loads never drop below 8 kilowatts. And that's huge because if you assume store closure between 10:00 PM and 10 AM daily, that's around $7,000.00 per store per year in energy cost. So if you extrapolate that across all the buildings in a portfolio, that's pretty significant and that can be one of the ways that you can persuade a building owner or your CEO, whoever it might be, to invest in plug load energy reduction strategies.
Here we are showing one interesting plot. And when you do a plug load study in your building you might want to try to make this same graph. We have a list of the most common plug loads in a retail building. The number in parenthesis is the quantity in a building. So you could see that TVs, in this particular building there were 44. By far they're the highest in quantity. This graph is really useful because it can show you how items that you would think have a very small load, when you aggregate them up, when you add them all up, they can have some of the largest plug loads in your building. For example, there are only 12 vending machines in this example building, but it's the second largest plug load energy consumer in the building with an annual energy cost of almost $5,000.00.
So I'm gonna pass the talking on to my colleague Chad Lobato, and he'll walk you through the rest of the presentation.
Thank you, Michael. I'll continue walking through the process that we've developed here. The next step, step number 3 is developing a business case for addressing plug and process loads. So business case is needed to help gain buy-in from all parties and to provide financial or business incentives to implement these plug load reduction strategies.
For most buildings energy consumption and energy cost savings will be the first business case that's developed. But in a lot of cases energy cost savings alone won't be enough to justify some of these recommendations and you'll have to develop non-energy related business cases. And a good example of a non-energy related case would be the use of laptops. Laptops do offer significant energy savings relative to a desktop computer. But their energy cost savings don't necessarily justify purchasing the new equipment. But laptops do offer increased productivity because of a more flexible computing solution.
So you'll have to come up with some non-energy related business cases to help make these strategies cost effective or effective for your building. Another example of a business case that we actually used here in the RSF was avoided cost of renewables. This business case is a strong business case for any building that's gonna be providing renewable energy generation to help offset the annual energy consumption. And it's basically equating the cost of the plug load reduction strategies to the avoided renewable costs.
Here in the RSF at NREL, based on the project specifics such as site, location, and building orientation and PV manufactured specifics, every 1 watt load within the building required 6.6 watts of PV system to offset the annual energy use. So for every watt that we were able to reduce in the building, we were able to save $33.00 or avoid $33.00 worth of PV costs. And our plug load reduction strategies resulted in a PV savings of $4 million dollars. We didn't have to buy $4 million dollars worth of PV to offset the annual energy use. So it provides a strong business case for those buildings that are gonna be providing renewable generation.
And the next step in our process is identifying occupants' true needs. So true need is the equipment or procedure required to meet or to achieve a given business function. So the champion needs to understand what the occupants do and what they are producing as part of their job functions and what tools they're gonna need to meet those job functions. And the champion will also have to address every occupant within the building and this includes the sensitive operations such as executive management and security and IT and any item or any group that may have previously fell outside of kind of typical control strategies. The plug load champion needs to address and account for all of the equipment that's gonna be going into the building.
And some cases during the inventory process, the champion's going to come up with items that are not necessary a true need to the building and that nonessential equipment needs to be addressed on a case by case basis. And a business case needs to be established as to why that equipment is used and if it's a reasonable business case then the plug load champion can work to develop an efficient strategy for that particular piece of equipment. A good example of this nonessential equipment is a coffee maker. So everybody in every building is prone to have coffee. It's not necessarily a true need that allows them to meet their business function, but it's something that the occupants definitely want. And rather than allowing people to have a personal coffee maker at each work station or at each desk, the plug load champion can implement a centralized coffee station so that everybody still has access to the coffee that they want, but they're meeting that need in an efficient manner.
So the next step is meeting the needs efficiently. So the plug load champion has determined or evaluated the true needs of the occupants and now it's up to the champion to develop a method of meeting those needs efficiently. And that begins with securing energy efficient equipment and in many cases you're gonna want to go out and implement the most efficient equipment that's available in some of the energy efficient equipment databases such as Energy Star or EP. The champion needs to review the equipment list that are rated in these databases and come up with the most efficient equipment that will meet their needs and allow them to reduce the energy use. You'll also find that there are certain pieces of equipment that aren't rated. They're not available in these energy efficient databases. In those particular cases, the champion needs to work with equipment manufacturers to develop efficient options. And then work to turn off that equipment when it's not in use. And need to pay particular attention to the parasitic load or the load of the equipment while it's plugged in and sitting idle or not in use.
And the graph that's at the bottom of this particular slide is showing several things, one being in the blue line that we've started out with efficient equipment. So we've implemented a low power laptop computer with a low power LED monitor. And the blue line is showing that equipment sitting idle, not in use, but at relatively low compared to say a desktop computer and CRT monitor which may be closer to 150 watts while sitting idle.
And then if you implement monitor standby features so that the monitor goes into standby instead of sitting idle and running a screensaver, you can transition from blue line down to the orange line and save energy that way. Or you can take it a step farther and implement standby settings on both the computer and the monitor and be operating at the red line while the equipment is sitting idle.
And that kind of brings me to the next step, which is step 6, is turning off all the equipment. So a big piece in any plug load reduction strategy is turning off the equipment when it's not needed or not in use. So in an office building, for example, the office building is only occupied about a third of a year. The rest of the times are nights and weekends and holidays where there building is unoccupied. And if we focus in on just that third of the year that the building is occupied, even less of that time are building occupants sitting at their workstations. Some recent study showed that 30 percent of the time that office building occupants are at work, they're at their desk. So the result is that only 7 percent of the year is office building occupants at their workstation. So that equipment should be turned off 93 percent of the year to help save energy.
And turning it all off in a retail environment is important as well. So this graph at the bottom of the screen here shows the measured load profile for a cash register. And you can see that the cash register operated at a fairly constant load regardless of the time of the day, but there's a significant amount of wasted energy that's occurring during the night time or non-business hours. And by putting the cash registers into a standby state when they're not used or de-energizing them during non-business hours, there would be significant annual energy savings for cash registers.
And this is a flow chart that we have put together to help plug load champions determining methods of controlling their equipment and helping getting that equipment to turn off. In this flow chart, the champion will be asked a series of questions that will help them analyze the use of the equipment or analyze how the equipment is used and then help to determine a correct or best suited strategy for controlling that piece of equipment. And this flow chart is available for download at the link at the bottom of the page here.
And this is the primary driver for the flow chart that we just showed. There are many commercially available plug and process load control devices that are on the market. All of them promise great savings. The problem is that they don't provide the guidance that allows the user to determine which particular control device is applicable to a certain plug load. And our flow chart helps the champion analyze the equipment and then determine an appropriate controlled strategy and a controlled device.
And once you go through the flow chart and determine applicable control device or control strategy, we also include a way to determine what devices are cost effective. So the user can set a desired payback period, in this example two years and then also implement their utility rate of say 6 percent or $0.06 a kilowatt hour in this example. And then based on the device cost on the horizontal axis, the device cost of $80.00 per control device, any load that is greater than 100 watts is cost effective to control. And we have additional cost justification charts available in our report Selecting a Control Strategy for Miscellaneous Electric Loads, and that is available here at the link at the bottom of the page. And then depending on your desired payback period and your utility rate, you can determine if the given device is cost effective.
So that brings us to step 7, which is institutionalizing plug and process load measures. So, as we mentioned before, energy use on plug loads is highly dependent on occupants and the decisions on how they use it. And a way to help reduce energy use from the plug loads is to institutionalize procurement processes to make sure that efficient equipment is brought into the space and then also institutionalize kind of operational programs or policies that encourage efficient operation of the equipment and help get people to turn off the equipment when they're not using it, when they leave the building.
And in this step, the champion is likely to come up on policies that maybe can't be changed or they can't be broken. In those particular cases the champion needs to address those issues on a case by case basis and work with the people that are in charge of these policies to help determine if there are things that they can do to improve the operation to make it more efficient and to reduce the energy use.
And that brings us to the next step, which is addressing unique plug and process loads. A good example of unique plug and process load would be food service areas in an office building. So a food service area in an office building would likely be operated by an external contactor or vendor and the building owner is still held responsible for the energy use of the equipment that the contractor brings into the space. In that particular case, the building owner should set contractual requirements that make the vendor provide efficient equipment and then operate it in an efficient manner by turning it off when it's not being used. And the building owner could also provide the vendor with efficient equipment if the vendor isn't willing to provide that efficient equipment.
Other unique plug and process loads such as ATMs may or may not be able to be controlled so the champion needs to address those, again on a case by case basis to determine if there's a more efficient option. And in many cases the manufacturers can help provide those recommendations for more efficient equipment or options.
So the next step, step 9 is promoting occupant awareness. And occupants do drive the energy use in plug and process loads. So you want to develop strategies and policies that help get the occupants to be aware of their energy use. You want to encourage the occupants to be good occupants. You want to encourage them to turn off the equipment when they're not using it and to question some of the previous operations and see if there's a more efficient way to do what they used to do. But then you also want to implement strategies that will counteract the bad users or counteract the times where they may forget to turn off the equipment.
And the picture on the lower right hand corner is an image that we have actually implemented here at the RSF. It's simply a sticker that we put on all of the computer equipment and monitors as well as some of the light switches in the building to help get the message out to the occupants and help them realize that their decisions definitely impact the annual energy use of the building and we need everybody's effort to drive down the energy use.
And this is also key in a retail space. But the retail space adds a little complexity because of the different audiences. So you will have an audience, an employee audience where you can provide direct training or provide the signage to get the employees to drive their behavior to reduce energy consumption. But then you also have a customer piece where you may or may not be able to drive the customer to reduce their energy consumption. But you can provide them with signage that explains the energy efficient measures in your store, and also inform the customers that they are supporting an environmentally friendly practice and help get them to open up their eyes to what you're doing.
And the picture in the lower right corner is an example of signage that's placed in a large retail store that is highlighting the efficiency strategies that are implemented in this particular environment or this particular store. And the final step would be addressing plug and process loads that would be responsible via design team in a heavy retrofit or a retrofit or new construction project.
The design team has the ability to specify or implement several strategies that a typical building owner may not be able to do. So the design team should question standard specifications and operations and see if there's a more efficient way of operating. The design team is also able to maximize space efficiency which is basically reducing the number of real dense plug load areas such as break rooms in an office building or print and copy rooms in an office building. And really increase the number of people that use each one of these common areas, dense plug load common areas so that the equipment within that space is better utilized and the physical number of devices in the building is reduced and the associated plug load energy use is reduced.
The design team is also able to build in control strategies into the electrical system whether that's adding say light switch controlled outlets, the design team could implement switches in the electrical system so that you can flip a simple light switch and disconnect the power going to a set of outlets. Or you could add occupancy sensors or vacancy sensors to outlets to help control that as well as adding timers. So the design team has the ability to implement the control into the electrical system directly as well as specifying some of the big energy users such as elevators and transformers and making sure that you have efficient elevators and maybe regenerative elevators that allow you to produce energy or transformers that are very efficient so you don't have the energy loss in the transformer system. As well as the design team specing up process cooling systems for areas such as data centers which are a little bit different than maybe a standard H pack system in the building. So the champion needs to work with the design team to help specify some of these unique plug and process loads.
And now that we've gone through the ten steps in our plug load reduction strategy, the guides do offer some simple recommendations based on either space type or equipment type. And, for example, both retail and office guides specify laptop computers or mini desktop computers over a standard desktop computer to help reduce the energy use. Or they recommend replacing aging inefficient monitors such as the CRT monitor with some of the best in class LED backlit LCD monitors. And various recommendations are provided based on the space type or equipment.
The guides also provide a worksheet that will help you in the inventory process to keep track of the equipment that's in your space as well as provide a calculator that allow you to calculate potential energy savings if these strategies are implemented in your building. And it's a situation where you can enter in your utility rate and your hours of operation and number of business days per year and then simply filling out a quantity column saying that you have, for example, ten vending machines in your particular building. That will then provide you an estimated energy savings by implementing our strategies and also provide an estimated cost savings as well.
And those calculators are available for download at the links provided here and revised versions will be available shortly. And at that point, it brings us to a conclusion on the presentation and I guess we'll be available for questions and answers.
Yes, so I would like to encourage everybody now to go ahead and submit any questions that you have using the Q&A feature at the top of your screen. I think we do have one or two teed up that Michael, if you'd like to take it away with that first one and we'll keep going.
Sure. The first question is, 'how did you determine the cost per store for plug loads during unoccupied hours? What rate did you use?' Give me a second to think about that. Well, the rate that we used is just $0.10 per kilowatt hour. We realized that utility rates vary widely across the country so just as an approximation we used $0.10 a kilowatt hour so keep that in mind when you look at that.
I think that you're referring to the graph of submetered data that I went over and it showed that about $7,000.00 a year is being wasted at night with plug loads being left on. We looked at the actual unoccupied hours of the store, which was roughly 12 hours a night I believe. And we multiplied that by the utility rate and that gave us on a yearly basis around $7,000.00 being wasted just at night leaving plug loads on. And so it looks like there – what's the next question? I'm having trouble seeing it.
The second question that we got was, 'how does NREL counteract bad users?'
I could take that one.
Go ahead. Yeah, sure.
So NREL, here at NREL we try to counteract the bad users in the form of the power management surge protector that was shown in the example of the low energy workstation. And it's basically a power strip or a smart power strip that will measure the power drawn on a given outlet and if it sees that say the monitor, our desktop monitor, goes into a standby load, it will then cut power to the remaining controlled outlets. In addition to counteracting bad users, we've gone through and specified the low energy equipment so that each one of our workstations, is you're only using about 70 watts while it's in use. And that includes all the equipment at the workstation. So we started off with the efficient equipment to help drive down the energy use and then we implemented the power managed through a surge protector to get that equipment to turn off.
All right, looks like the next question here, the next set of questions is, 'do you have any tools for monitoring PPL in hotels and are there any tips you can provide for hotels versus office and retail?' Anything special probably to hotel operation.
We haven't developed a guide specific to hotels. For the most part though, the equipment that you're gonna find in hotels is gonna be very similar to the equipment that you see in the office space or the retail space. In the office area of the hotel, the office guides are gonna be very applicable to that equipment. The room themselves, you may have to look into some other options. But the producing or procuring efficient equipment such as buying low energy EPs for each room is still gonna be very applicable.
And then we've seen in hotel rooms where in order for the room to be powered on, customers have to put their room key near the door and that enabled all the lights. And when they leave, they have to take their room key with them and that power down the lights when they're out of the room. Again, we haven't studied hotels specifically, but one tool, if you're asking specifically for tools; I would recommend downloading that flow chart that we presented in our presentation. Now this flow chart, it may be intimidating to look at it first and we're actually working on developing it into a more usable version, but it will, for every plug load, it doesn't matter if it's in a hotel or if it's in a retail - I mean in an office building, it will help guide you to the correct plug load control.
And it looks like we've got another couple of questions. The next one is, in your experience, what's the easiest low hanging fruit when it comes to reducing plug loads?
Okay, well –
The first thing is gonna be matching your plug load energy use to actual building occupancy. One of the first things we try to stress is getting the equipment to turn off when it's not needed or not in use. And that may be just providing the occupant awareness and getting people to turn off the equipment. So in the office example, at the workstation, the workstation is only occupied 7 percent of the year. So 93 percent of the year, that equipment should be in a zero power state or lowest power state possible. So the first thing you should do is get that equipment to turn off when it's not in use, and then from there you could start specifying the other strategies or implementing other strategies.
Chad makes a good point and to go a little bit further on things we've done in our office building, it doesn't just have to be encouraging users to do good through education, we've actually installed timed outlets for our ice machine and that significantly reduced the load of our ice machine saving tons of energy and basically justifying the cost of the outlet timer you can probably buy at any local hardware store for pretty cheap. Within a few months I think it paid itself back off so really, like Chad said, the key is matching use to the device actually being powered on.
And another question that we received is, do you have any suggestions for shutting down computers or laptops after hours?
Well, there are a number of strategies that you can implement. And we've implemented a few within our own group here NREL. And Chad's already mentioned the surge protector that will power off or cut power to your devices when the master plug basically goes to a low power state. But beyond that, we have a device that is a remote standby triggering device. So you trigger this device, it's external to the computer and it's plugged in via USB and when you click on that, it sets your computer into standby mode. So that's an easily accessible little switch for people to hit and it helps encourage good behavior.
Also there's a setting on all of our computers where if you hit the power button on the docking station for the laptops, it'll switch the computer into a low power state. Chad, do you have any more to add to that?
I think the first step would be implementing any of the built in energy saving mode so set up the computers. Have the IT department push out the built in standby functionality and set pretty aggressive settings on those standby options. And make the monitors go into standby after say 5 minutes of inactivity and make the computer desktop or laptop go into a standby mode after about 15 minutes of inactivity. And in most cases the users could then come back and easily get the equipment to power right up and be available for use almost instantaneously. But implementing the built in strategies and then if the built in strategies aren't functioning reliably then there are third-party software packages that you can install that help transition computers into low power states or as Mike mentioned, there are other kind of hardware based solutions that allow you to hit a desktop mounted button and get the computer to transition into a low power state.
All right, it looks like we got another question just now. And it is, how do you think building automation systems can help boost or bring additional energy saving from the TPL other than the standalone TPL control solution?
I'll go ahead and address this. In one store that we worked with, we found that when they organized all their plug loads onto – well, the first step they did, they organized their plug loads onto a given set of circuits in their electrical panel and using the building automation system, they're able to meter that separate from all the other building loads. Now, they haven't taken it that step further and used controllers that interface with the building automation system to reduce those loads during unoccupied hours. But that would be the next step is to on these organized plug load circuits install controllers that – they're commercially available – install those and set them up such that the ones that can be de-energized at night are de-energized through the building automation system.
All right, it looks like we've run out of any questions that we have so I'm gonna give everyone just a minute to submit any additional questions if you have them. All right, it looks like folks are out of questions so I wanted to go ahead and take this opportunity to wrap things up here. I wanted to thank our speakers for their time today and just let everybody know that we are going to post the full slide deck and a video of today's webinar at commercialbuildings.energy.gov/webinars and actually from that page there's a link to the webinar archives page where you can find all of the presentations that we have done thus far. And again that URL is commercialbuildings.energy.gov/webinars. Thank you, everyone, for your time today and thanks for sending questions.
Thank you for everyone's participation. You may disconnect at this time.
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