Energy Conservation Modeling for Weatherization Text Version
The following is a transcript of the Energy Conservation Modeling for Weatherization webinar. This webinar was presented May 25, 2011 for the Technical Assistance Program of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy.
Rebecca McEwen: Welcome to today’s TAP webinar sponsored by the U.S. Department of Energy’s EERE technical assistance program or TAP. Our presentation today will feature information on determining the feasibility and estimating the potential energy savings of certain energy efficiency measures when weatherizing homes. I’d like to begin by thanking all of you on the phone for joining us this afternoon. I’m here with Sarah Busche of NREL and Ed Pierce of Oak Ridge National Laboratory. We’re broadcasting from NREL’s brand new state of the art research support facility in Golden, Colorado. We’ll give people a few more minutes to call in and log in, so while we wait I’ll go over some logistics. After that Sarah will provide a little bit of background about TAP and then we’ll delve into today’s topics.
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Sarah: Thank you very much, Rebecca for giving us all the logistics that we need to get this thing going. My name is Sarah Busche and I’m with NREL and I just want to give a little overview of the technical assistance program. You can see that this program provides you access to the expertise of a variety of organizations across the U.S. This is the National Labs and other organizations that support DOE in this assistance. With the laboratories we provide assistance across the board from strategic energy planning to policy and program design and evaluation all the way through to program development, and this includes things like identifying the most appropriate technologies and financing options to project citing and technical bid reviews.
We encourage you to check out some of these resources. If you have questions or need more information on energy efficiency and renewable energy options there are a lot of resources available on the solutions center, and from there you can also access technical assistance by going to the Technical Assistance Center or TAC, and if you have any questions you can email the email address at the bottom, which is firstname.lastname@example.org. There are a few upcoming webinars I also want to let you know about that are offered through TAP. This is using social media to engage the community for energy savings, and policies and procedures for enhancing code compliance. You can see those later this month. So without any further adieu I think, Rebecca, should we get moving?
Rebecca: I think that sounds like a good idea, Sarah. We would like to introduce today’s headliner, Ed Pierce of Oak Ridge National Laboratory. Ed is a member of the senior research and development staff in the energy and transportation science division at Oak Ridge. He has more than 35 years of mechanical engineering experience in thermal analysis, energy analysis, CHP system analysis, energy auditing, and HVAC and energy system engineering. Ed, thank you for being here today.
Ed: Thank you, Rebecca.
Rebecca: And Ed, you should have control of the mouse.
Ed: Yeah. That’s what I was checking out right now. What I’m going to talk about today is a general overview of energy modeling as can be applied to any kind of facility or various types of systems that you may encounter in different facilities. What I’m going to look at is why is energy modeling important. I’m going to look at some calculation methods and then which method would be best to use and how to determine which method is best for you to use, and then give an overview of some modeling tools that are available to help when you’re modeling energy use and savings in various types of facilities.
Energy modeling consists of applying engineering calculations to predict energy use. An energy estimation model can consist of manual calculations or mathematical representation in a complex software tool, so there’s a whole spectrum of what’s called energy modeling and the reason it’s important is that when you incorporate any energy conservation measure the savings is a difference in the estimated energy use for the base case and for the base case with the energy conservation method incorporated. So you have to have energy estimating in order to be able to determine how much savings you’re going to be able to achieve with specific energy conservation measures.
Rebecca, I have lost my – okay. I lost my little arrows. I guess I’m having problems with the – oh, here it is. I got it back. When I lose those little arrows it’s hard. Okay, so now we’re going to the calculation types and I’m sorry for the delay there.
So then we look at different calculation methods that are manual methods, which are primarily steady state and situations where things are not changing very rapidly. If the steady state calculations are dependent on weather then there’s a method that’s called degree day method or the bend temperature method, and then if not, if it’s not highly dependent on weather then there’s just simple energy calculations. There’s also computer methods. These are divided into two groups, which would be whole building modeling software and system component level modeling software.
If we look at the manual calculation methods just a second then, the steady state, and as I said before it assumes little or no change in the parameters, which affect your energy use. That can be performed quickly and they’re relatively simple, but the thing is they’re best for rough orders of magnitude and that you can get significant errors in the calculations. Then when you look at dynamic calculation methods, which are the whole building computer simulations, they’re primarily used when external or internal factors are wide ranging and constantly changing, therefore requiring hourly analysis or hourly simulation. As I said they’re usually performed with a computer because doing the hourly calculation is very time consuming. A computer can do it pretty quick.
Since these are hourly calculations and they are dependent on the weather data, these software tools use hourly weather data, and in these cases the inputs are more difficult because you have to accurately define this facility that you are trying to model and they’re used for detailed analysis and they can be fairly accurate. So now in determining which methods you should use there’s no cookie-cutter answer for which method to use. You have to look at each situation and assess the parameters like accuracy, what level of accuracy is needed. Again if a rough estimate is sufficient then that may send you in one direction, and then how well does the method match the actual use.
Then the complexity is another parameter that needs to be looked at, how much input data is needed or available. If you try to do a complex whole building analysis and you don’t have all of the data that you need in the building then you might as well use a simpler technique. Then cost. When you’re doing a whole building or dynamic type of simulation to determine the energy use, is it worth the time and the effort? Again if a rough estimate will suffice for what you’re trying to do then there’s no need to go into the whole building type analysis, and again you look at availability of the data. Is the data available so that you can do a modeling effort at whatever level you would like to?
Then to go back for just a second, we’re going to look at the two methods that I mentioned before for steady state calculations and that’s the degree day and the bend temperature method, and these two methods are discussed in detail in many energy engineering textbook and even on the web. You can get pretty detailed discussions about each of these methods. In the degree day method it’s primarily for a single measure and it’s based on a balance temperature in a degree day, and the balance temperature is an outside air temperature for a specific specified interior temperature. The total heat loss is equal to the total heat gained.
So as it says it’s a balance point in your system, and then one degree day would be a 24-hour period where the average outside air temperature is one degree different from the balance temperature. The advantages of this as I’ve already said is it’s quick and it’s simple and it can be used for rough estimates. The disadvantages of this, it doesn’t count for all of the variables that could be involved in your energy use. Again you could get sizable errors there. I’m not going to go through this. This is just the typical degree day method equation, helps you estimate what the energy use is going to be for the degree days. Like I said, this is just an example and I’m not going to go through this whole thing.
Then if we move over to the bend method it accounts for weather variation by using bend temperature data. The first step is to define the energy use for a facility or a system for various outdoor air temperatures and the way that that’s done a lot of times rather than go calculate the energy use for a whole list of outside air temperatures is you can do a few of the temperatures and then plot the results in curve plotted data, and then use the resulting equation to determine what the energy use is at the various temperatures. The second step is you take these energy uses at various temperatures and then the number of hours that that temperature occurs and from that you can determine exactly, or not exactly, but an estimate of what the energy use is.
Rebecca, I keep losing arrows down here. I went too many slides. I need to go back one. Okay, it’s back now. These are just general equations. I’m not going to go through these equations in detail or anything, it’s just you’ve got equations for determining the load for each bend and then using the full load fraction, I mean the full load capacity to determine the part load fraction that occurs at that temperature and then you have an equation where you can determine the amount of energy that’s used.
This is an example of temperature bend data, and you can see that the temperature bends range from 0 to – these are in 5-degree bends and you can see that the bends are from 0 to 4 degrees all the way up to 100 to 104 degrees. You can see the outside air temperature that you use for evaluation is the mean of the temperature bend, which as you can see here. Then when you’re adding up the occurrences of this particular temperature or this temperature bend and you can do it at various hours during the day. If you wanna know how many times that temperature occurred between 1:00 and 8:00 or whatever you can determine those and then do the calculations. This would be where your load changes significantly from those hours. Like maybe people come into the building or people come into this facility or they leave this facility, or you can just do it based on total observation.
Then if we look at the whole building analysis or calculation of the energy use for whole buildings, there are a whole host of whole building energy analysis programs out there and no two programs are alike or will produce identical results. They all will produce generally the same trends or the same answers but not identically.
It’s usually generally accepted that the results of a computer model can be considered good if they are within 15 to 20 percent of the actual measured energy consumption of the building.
Rebecca: This is Rebecca. We’re getting a bunch of questions in from the audience to ask if you could define what bend data means.
Ed: Okay. What this bend, the temperature bend, is how many hours a day the outside air temperature is between 100 and 104 degrees. So that’s the bend, and then when you do your energy use calculation you base it on the average of that bend temperature, which is 102 degrees. So this over here, the observation hour group, it’s the number of hours during the specific time periods that that temperature occurs. Here the temperature was between 75 and 79 degrees four hours between the hours of 1:00 and 8:00, and then over here is the total number of observations irregardless of what time of they day they occurred. Rebecca, is that –
Rebecca: Ed, that’s perfect. Thank you very much.
Ed: Okay, so let’s move on back. As I mentioned these whole building tools require weather data files and since they perform the hourly calculations you need a file containing the weather data. Many of the software tools you use what’s called TMY 2 or typical meteorological year weather data. These are available for 239 U.S. locations.
Rebecca: Hello everybody, this is Rebecca McEwen. We seem to have experienced a moment of technical difficulties. We will hold on just a moment for Ed to come back on the line. Ed, are you back with us? Ed? We were wondering if you can check your headset. It may have gone on mute. Okay, we’re going to give Ed just a couple more minutes to dial back in. It looks like there was a break in our communications line, but he should be back in just a moment and we’ll just hold the line for him.
Ed: Rebecca? Am I back online?
Rebecca: Ed, you’re back. Okay. Excellent. Good news.
Ed: Did I get back on?
Rebecca: You’re back on and we can hear you just fine. Thank you very much.
Ed: I think what got me there is an energy conservation measure that we have here. We have a motion detector that turns off the power strip when no motion is detected. Are you still there?
Rebecca: All right. Go ahead and continue your presentation. I’m glad we all hung on the line for you.
Ed: I’m sorry.
Rebecca: Oh, no problem.
Ed: These weather files, their intended use is for computer simulation and comparison of energy conservation measures. The steps that I use in measuring or developing a model or measuring energy use is first of all you build the base case model and then you compare the results with measured energy consumption. Usually it’s better to have more than one year of energy consumption because you’re using the typical weather file and therefore you need to kind of average several years worth of data, but then you can adjust the parameters in the model to make it match the measured energy consumption as close as possible.
Then once you get satisfied with your model then you can incorporate your energy conservation measures and develop what’s called an energy project model, and then you compare the results of the two models to determine what the savings are. I’m sorry, just a second. Let me get my papers. Okay, then the home building modeling software, like I said before, there’s a whole spectrum of this software and I’m only going to talk about two of ‘em. Really I kind of consider them the extremes, and that’s Energy Plus and E Quest. Energy Plus you have to provide a detailed description of the building envelope and system and its operations, and in E Quest they have predefined building shapes and systems and then you can just select them, so E Quest is a lot easier and a lot quicker to generate a model than Energy Plus is.
Then I’m going to talk about some specialty tools, which is the CHB screening tool and the data center tool suite that can be used for data centers, and then Energy Plus as I said before you have to provide a more detailed description of the building and based on that it can escalate your heating, cooling, lighting, ventilation, water usage, everything that you need to do an integrated evaluation of your building energy club. As I said before this Energy Plus is one of the most robust simulation tools that there is, and I’ll show you an example in just a few minutes that might stress that a little more, and it’s a stand alone simulation program without a user friendly graphical interface. The program reads input and writes output as text files, but the good news is there are graphical interfaces that have been developed to simplify creating anything and running Energy Plus input files.
This program, you see how well it’s used. It’s been downloaded in 120 countries. Let me go back one or two slides here. Okay, this software is Energy Plus. It’s free software and it can be downloaded from this website. Energy Plus as I said before you have to provide a detailed description of the building, its physical makeup, its mechanical systems, and then Energy Plus can do calculations as I said before on heating/cooling loads, and then it also does a simultaneous solution of the various loops that can be defined on Energy Plus, and in Energy Plus you can have primarily three different types of loops. You can have an air loop and a plant loop, which is hot water, steam, _____ water, and a condenser loop, and the software determines the interactions between these various loops so that you can run the air loop and it tells you what the temperature requirements in the hot water loops are. Then it also gives you energy consumption of the primary equipment, and then it does use the TMY 2 weather data file.
This is just an example of a model that I built of a retail facility, and it has 15 zones in it and 126 heat transfer surfaces. The reason it’s a little more difficult until you really get used to it is each one of these heat transfer surfaces has a coordinate system and you have to define that surface in a coordinate system, but then you also have to define each surface coordinate system in a building coordinate system, so that’s where it gets kind of complex in developing these models until you get familiar with it and then you can do it pretty fast, but these graphical interfaces help you with that until you do get to that point.
Then Energy Plus has some innovative features. It can look at time steps less than an hour. You have something that’s changing rapidly and you want to estimate the energy use every half hour or every 15 minutes then you can do that with this model. It has multi-zone airflow. You can model airflow between two separate zones. Then it’ll do natural ventilation, and this is just a list of the things it will do. Then if we move on to the Energy Quest you can be able to see the difference in it, and again it’s easy to use. It’s DOE 2-based software. It’s based on the DOE 2 energy analysis tool. Like I said before, it’s a lot easier to use and it’s designed to allow you to perform a detailed analysis without requiring extensive experience in DOE 2 modeling. Then again this is a piece of free software that you can download, and I’ll give you the website.
Then with this tool you can model various system configurations – air cool systems, water cool systems, systems with multiple unequal size tillers or different tillers operating together and bearable flow systems. These different type systems are in the software and then you can just make slight changes to ‘em to put in your specific parameters. All of this analysis with this tool is accomplished by what’s called a building creation wizard, and this helps you to create the model of the building. It has built into it 30 different building types, 10 different building shapes. You don’t have to put in all of the heat transfer. There’s eight different area types that you can model, kitchens and conference rooms and offices and things like that.
Then it has what’s called an energy efficiency measure wizard where you can select the various energy conservation measures you want to analyze and the categories of these measures are building envelope and internal loads, HVAC systems, till water systems, and domestic hot water systems, and then you get graphical reporting of your results as well as tabular results, and as I said before the simulation engine used to derive the loads that are needed by this software is DOE 2. Then again it uses TMY 2 weather data. The website is listed here in the last bullet that you can download this piece of software from. This is just an example screen of the input. There are drop-down menus where you can change the various parameters that you wanna change or put in the building area.
That’s the good thing. The bad thing is there are 41 of these screens, but you can go through ‘em pretty fast. It doesn’t take an extensive amount of time to go through them. Then I mentioned there are ten different building shapes, and this is just one of the typical shapes that you can select and define to the program, this is what I want my building to look like. This is pretty routine. It’s just a square. It also has some sophisticated building types where here you have an H type building, so you can select that, and it has a whole range of building shapes and it’s usually you can find one that matches your building pretty well.
Then they have the results, the graphical output to the electric consumption, the gas consumption, by end use. Then one of the specialty programs that I mentioned is building heating and cooling loads between the building combined heating and power screening tool. This is a tool that we use quite a bit and it’s for evaluating THP systems in commercial buildings. It consists of an executable program and several equivalent databases that you can select equipment from, and also since it needs hourly loads in order to simulate the heating, cooling, and electric consumption, it uses DOE 2.1 E to determine these loads, and then currently it uses blended electric rates and by that we mean total consumption, total cost divided by total consumption. It doesn’t differentiate between kilowatt hour costs and demand costs. They’re all wrapped into this building blended rate, and it uses TMY 2 weather data
Then I mentioned the databases. This is a whole list of the databases that are available, and you can go in and pick out specific equipment in each one of these categories. It has 14 different building types or prototypical buildings that you can select from the software. Again you don’t have to put in all of the heat transfer surfaces. Then all I really wanted to stress on this is it does use the DOE 2.E software to do the background calculations, and this is also free and can be downloaded at this website.
All of the tools that I’m showing you or talking about today are free. Of course there are programs you can buy, but these are all free and you can download them from these websites. The input and output to this program, the tool handles the input and the output through pull-down menus and again it doesn’t read text files, so it has been done to make it easier to input the data. Then there’s a lot of default values in there with the templates that are there and you select a building type. There’s a lot of default _____ you can use or you can put in the actual numbers that you wanna use. After the DOE 2 simulation is run then the outputs are extracted from the DOE simulation tool and made available to you in the main table tab where you can select on those or you can get graphic outputs as well.
Then I mentioned the equipment types and the combined heating and power equipment types that are located in there are internal combustion engines, turbines, micro turbines, fuel cells, and combinations of fuel cells and micro turbines. Then move on to the data center profiler and it’s designed for people that have data centers or facilities that have data centers that want to know how energy is used in the data center and ways that you can save energy in those data centers. It consists of three different tools.
Again this is downloadable and it’s free, comes from the DOE best practices website, and there’s a profiling tool, an energy management tool, and an electrical systems tool that you can use to get an idea of how your energy is being used. As I said the profiling tool is kind of the first step and it’s an online software tool that you can use and just put in a limited amount of data and it’ll identify potential savings and also the reduction in emissions that you can achieve with these different measures. The inputs you have to put in a description of the facility, utility bill data, and information on the electronic HVAC electrical and on-site generation equipment. The outputs that it provides you is like I said before, an overall picture of the energy use and efficiency and a break down of the end use energy usage and either side or source units. It identifies potential areas for energy efficiency improvement.
The second tool is the air management tool and this again is in computer centers and air management in data centers is important both from an energy and a thermal standpoint. The air management in data centers is essentially about keeping cold and hot air from mixing. You don’t want the cold supply air to mix with the ambient air, and you don’t want the hot exhaust air to mix with the ambient air or the cold supply air. You want it to return to the air handler without mixing. This tool is mainly for raised floor cooling and hot and cold. Like I said, you can use this tool to identify air management recommendations, pinpoint potentials for reducing airflow and temperatures, which will impact your energy use and can result in a savings in your energy use. It’ll also look at the energy reductions and the fans and chillers that are supplying the data center.
Then the third tool is the electrical assessment tool. It’s designed to assess the potential savings from energy efficient actions in the electric power chain of a data center including transformers, generators, uninterruptible power supplies, and the power distribution. This tool estimates savings based on typical practice and the actual savings will vary based on site specific conditions. I’m going to briefly go through several system level tools that are available that can be used to model systems, and I’m going to go through these pretty fast since our technical problem has cost some time.
Here is the list. All of these can be again downloaded from the DOE best practices site, and they’re all free. The esteemed system tools suite is one of the ones that I personally use a good bit and then it allows you to evaluate savings that are possible in a steam system. Again it consists of three different programs: a scoping tool, an assessment tool, and then 3E Plus, which is an insulation system evaluation tool.
Use of this tool suite, each software tool requires some different data, but in general the data you need to run this whole tool suite, the three programs, are general data about the system and then data about your generation system, your boilers, efficiency of the boilers, blow down rates for the boilers, and then information about your distribution system. Are there steam turbines in your system? What kind of piping insulation do you have and steam drips and leaks? Then also you need data about your end uses and your condensation return system.
The outputs that you get from this is operational cost for fuel, electricity and water, and emission, and it also calculates for you what your cost of generating steam is, how much does steam cost you per pound or per 1,000 pounds, whatever unit you wanna look at that in, and then I mentioned the scoping tool. The scoping tool is really just something, a scorecard that you can provide yourself with an assessment of how well the system is working and improvements that you can possibly get. What you do to use this tool is there’s a series of questions that you put data in about your system profile and your system operating practices and your boiler plant operating practices, and then it will evaluate your steam system against best practices. How does your system compare with systems that are designed for using the best practices guidelines?
Then like I said it will provide you a score and then also opportunities that you may have to improve your score or your system performance. Then the next tool, the steam system assessment tool is used to analyze potential projects. This one just is the profiling tool and gives you an overview. What the steam system assessment tool does is allow a steam analyst to develop approximate models of the steam system and it contains features that are typical to a steam system. Using these you can assess the quantity of the energy cost of emission savings of potential steam improvement opportunities.
I don’t expect you to read this. This is just a representation of the steam system that you might have or that you input, and this is a three-header model where you have a high pressure header, a medium pressure header, and a low pressure header. Then you can see the components that it actually has in here that you can add to your model to simulate boilers, steam turbines, pressure reducing valves, the end use of our steam, a de-aerator, and heat recovery, and then I mentioned you can select energy conservation measures and some of the ones that you can select that you want to be analyzed is changing that process, steam requirements, using alternative fuel, changing the boiler efficiency, changing the blow down rate, and changing the steam generation conditions, installation of steam turbines if they’re not already there, and condensate recovery, and steam trap losses, and steam release, and improvement of your insulation.
So move on to the insulation program that’s in this tool suite. It allows you to calculate the heat loss of various thicknesses of insulation for user input operating conditions. You specify the condition and it tells you what the heat loss is based on the type of insulation that you specify. It uses built-in performance data for generic insulation materials and you can also put in conductivity data for other materials if your specific material is not included in that database.
Then this is the pumping system assessment tool. It’s much like the steam system assessment tool and all of these are going to be about the same. It assesses efficiency improvements in pumping system operations that you might have, and then it uses pump performance data from the hydraulic institute standards and motor performance data from motor master plus database, and it calculates a potential energy and associated cost savings with various energy conservation measures that you might wanna consider. Then this is a list of the inputs. There’s a whole list of inputs, but what makes it easier is their pull-down menus where you can make selections or just type in numbers, so this data can be input pretty quickly.
It will provide you – the things that it will provide you is pump and motor efficiencies, and again like I said annual energy use and energy costs for existing and optimal equipment that you might wanna install in your system. Then there’s an equivalent tool that’s called a fan assessment tool and it essentially does the same thing that the pumping assessment tool. Helps you to understand how well your systems are operating and helps you determine the benefit of system modifications and what are the most economical modifications that you can make. Then you need again input information about your fan and motors and how you operate the fans and the motors, and the system flow and pressure requirements and the KW that is required, and it calculates how much energy your fan system is using and it determines how efficiently your system is operating, therefore you can quantify the savings for upgrading your system.
I’m going through these pretty fast because we lost a good bit of time there with technical problems. This is another system that you can look at. It’s a chill water system and you can build a model of a chill water system and assess its performance with this tool, and this is a system that I developed for one facility that we did some audits on. They had five 2,000-ton chillers and it had condenser water pumps and chill water pumps and you define those components, and then it will determine energy consumption and cost of chillers, pumps, and the towers.
It can be used to examine the energy impact of a change in operating scenarios. Maybe you change the way you’re operating your chillers or your pumps and it’ll quantify potential savings, energy savings and cost savings, and then if you have a compressed air system at your facility then you have a similar tool called Air Master Plus. It essentially does the same thing that the other system level tools do. It assesses how well your system is operating and gives you recommendations as to how you might improve it. Then you enter a bunch of information describing the existing inventory and those are listed here.
One of the things I might point out is it talks about typical operating day and what it’s looking for is what is a typical day for the operation of this compressor and other components, and if you have metered hourly usage or airflow for each day type then you can enter that as well. You might have on Tuesday, Wednesday, and Thursday you may operate these systems one way and Monday and Friday operate them differently, and that’s what the day types allows you to do is to identify and put those in, and this also uses pull-down menus and you can see here some of the tabs that you can click on to pull down the input screens to input the data and notice the one that’s highlighted is energy efficiency matter.
You can look at enhancements, which will reduce air leaks, reduce system pressure, reduce run time, improve your end use efficiency and some other things here that you can do to possibly save energy with your compressed air system. Then it provides the outputs that it provides in comparison with existing and the modified compressed air system operation and it evaluates the energy savings and the cost savings. It also has a log function that allows you to keep up with maintenance histories for the equipment that’s within the system.
Then the last one is the motor master. We use it a good bit ‘cause what it allows you to do is evaluate what is the most cost effective thing to do when you’re considering either replacing a motor, rebuilding a motor, or installing energy efficient motors when what you have currently are just standard efficient motors. Then it has a lot of features built into it as well like it’s 20,000 low voltage induction motors, the data for those motors. It also has a motor inventory management tool that allows you to log and track maintenance that are done on motors doing efficiency analysis and savings evaluation.
This software will allow you to do that and the things you input is your electric rate schedule and your operating schedules and then data about the motors, like the name plate information and the operating profile. Also if you have _____ measurements that were made as far as amps and volts for the motors you can put that data in and the software will calculate how well or how efficiently your motor is running.
You may have a 15-horsepower motor in an application where you only need a 5-horsepower motor, so it will compare the field measurements with the name plate information and give you an idea of whether it’s too big a motor and you can save money by downsizing that motor. You can look at things like that, and then the outputs that it gives you is how cost effective is it to repair or replace a motor or replace a standard efficiency motor with a premium efficiency motor. It gives you energy and dollar savings, simple payback.
It also gives you reports on the energy accounting and conservation tracking. Then in conclusion, you can see that I have been through several methods of evaluating energy savings and the importance of that is if you’re looking at doing an energy conservation project, one of the things that you’ve got to know is how much energy is this going to save you so that you can do some economics and calculate a payback period, ‘cause it’s hard to send projects to upper management unless you can tell them what benefit it is to this facility.
Then like I said, these are all free, downloadable from the web. There’s no cost for using any of these tools that I talked about, and there is ample training opportunities available for each one of these tools. Schedules for these opportunities can be obtained from the two websites that I have here, and then last of all I put my email address on here. If you would like to contact me, feel free to do so. Rebecca, I believe that’s it.
Rebecca: Ed, that was fantastic. Thank you so much. I don’t know if you have a few minutes, but we would love to be able to keep you on the line to answer a few questions?
Ed: Yeah. I’ve got time.
Rebecca: Excellent. Thank you very much.
Sarah: Great. Thank you, Ed. One of the questions we had was if you could talk a little bit about how often the utility service classifications and/or rates are update on E Quest?
Ed: They update these regularly, but one of the inputs you can put in is a rate that you have rates that are applicable to your size at that time.
Sarah: Great. So if your rates had been updated more recently than the ones that are in E Quest you could change that?
Ed: Well, and if you have a facility you know what you’re paying. You use so many kilowatt hours and so much demand and this is what it costs you every month. Then you know what those costs are, so you can input those so that it’s using current energy costs.
Sarah: Great. Thank you. Are you familiar with the Energy 10 from the Sustainability Building Industry Council, and if so, what are your thoughts on that?
Ed: Well I have run that software and I’ve used it for some analysis. It really gets down to a personal preference. Would you rather use Energy Plus or would you rather use Energy 10 or what do you feel comfortable with analyzing your energy usage? Personally when I have the time I prefer using Energy Plus. I’ve been using these building simulation tools all the way back to DOE 1, so inputting the detailed service descriptions is not really a big deal to me, but first time or infrequent users, they find that to be a big stumbling block, and that’s the reason those graphics, input and output graphics are available to help you get used to that.
In short, all of these tools really do the same thing. They don’t necessarily calculate the same numbers, but what you’re looking for is a difference. You’re looking for a delta in a baseline system and an energy conservation system or measure and you don’t want to compare Energy Quest base case to Energy 10 energy conservation measures. As long as you’re looking at using the same model and you’re looking at the deltas then that savings and all are comparable from these programs.
Sarah: Great. Thank you for talking about the differences between some of those models. Can you discuss some of the energy efficiency measures that would be associated with data centers?
Ed: Well I don’t know if I can get back to that. The things that you would like to look at like what I mentioned there when I talk about that is you wanna make sure you’re not over-supplying. You’re providing way too much air, which costs money. You have to run fans and you have to run chillers, that sort of thing, and then too what things that I mentioned or what can cause you to supply too much or too hot or too cold air is the interaction of those systems. The big thing in data centers is you’re looking at, okay, what does it cost to heat and cool this equipment? You don’t have to worry about heating it but to cool it, or am I spending too much money trying to cool and maintain the conditions and these racks of equipment?
Like I said, if you can decrease the airflow or the temperatures that you’re supplying then that’s where you can save energy and money in computer systems because being an HVAC design for many years as well, you always tend to put too much of a safety factor. You’re supplying more air than you really need just to make sure you don’t have a problem. So this tool helps you flush out those kind of situations.
Sarah: Great. Thank you. One of the attendees is interested in, you mentioned at one point a breakdown of utility end use, and I think it’s around slides 36 and 37, so we might have to go back to those just to reference this question a little bit, but the attendee is interested in having you elaborate a little bit on the differences and the breakdowns of utility end use.
Ed: In what type of systems are we talking about?
Sarah: Let’s see here. I’ll get back to those slides and see. I think it was when you were talking about E Quest.
Ed: Oh, okay. Do I have control again?
Rebecca: You should.
Sarah: I think. Let me know if you don’t.
Ed: Maybe I can get to the – okay, so this is like an electric _____ that has area lighting, task lighting, miscellaneous equipment, so it has various end uses for the energy and they’re all color coded. Like I said, there’s also tables of this data so that you don’t have to try to read it off of these graphs, but then you have that for electricity and gas as well. These are all based on what you input to the program. One of the inputs that you give is a lighting _____ _____ _____ the water heating density, the occupant density and those kind of things, and then it calculates the energy use based on or for these various end uses it has listed here. Whether it be Energy Quest or Energy Plus you get this breakdown from all of those software tools.
Sarah: So that would really help you identify which areas you’d want to focus on for energy efficiency measures?
Sarah: Great. Then just a final question. I know on your last slide you mentioned that there were some trainings available on DOE’s EERE site. Can you talk a little bit more about the trainings that exist and if they’re free, who can use them, and other things along those lines?
Ed: Yeah. I was trying to get to – most of these are handled by webinars where it’s a webinar that you can register for and dial into and then participate in the training. Now some of the more difficult programs or the more cumbersome programs, there are one-, two-, and three-day training sessions that you can sign up for, but the webinars are usually sufficient to give you enough information and enough feel for what the program does to be able to go ahead and use it, and each one of these or most of these have user manuals, which are in most cases quite good. They give you a tutorial. Here’s the way you go through an analysis using this tool, and it goes through an example.
So if I use those reference manuals quite a bit and I have been to several-day trainings on Energy Plus, those are like I said primarily real detailed courses in how to use the software. For Energy Plus if you’re not a frequent user this tool that DOE has where you submit your conditions and they run software and build a model for you and then send you the results and the files is really good for people that aren’t real frequent users and only use it every day or very infrequently. That would give you a model that’s a starting point. Then you can make whatever changes you want to to it as well.
Rebecca: Ed, thank you. Thank you so much for putting this presentation together and for this time this afternoon. I very much appreciate it, and I also wanted to thank everybody for participating in today’s EERE technical assistance program webinar. We’ve had a great audience and we thank you all for your time. Please check the NREL website next week, probably early next week, if you wanna view the PowerPoint slides and listen to a recording of this webinar, and we will send out the URL for how to access this in a follow-up email that will go out either later this afternoon or early tomorrow morning. Thank you everybody. Have a great day.