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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Merci, Mssr. Beaulieu.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I agree about using an 8760 hour simulation. The big issue is how to define the level of importance for various inputs and how that affects you speed of preparing the model. I think certain information can be assumed with reasonable confidence, some must be measured and some can be figured out by trial and error.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As you mention below, many owners / operators have no clue about the details of their systems’ operation, so you must attempt some trial and error to get a good fit, or spend a lot of time in the building. I like spending time in buildings, but my clients are not too excited about paying me to do it, so I’m looking for reasonable shortcuts.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As an aside, I think benchmarking is helpful if your building happens to fit one of the standard categories. It is NOT helpful to understand why the building varies from the category mean.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I am now walking the path of a three step accuracy level for an energy audit. <o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The first step is a “drive by” audit using basic building dimensions, age and HVAC & lighting system information along with utility bills. (No utility bills = no confidence about predictions.)<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Step 2 is gathering more detailed information from occupants about schedules and gathering data about key energy equipment (“gathering data” means measuring motor power and key operating temperatures, and observing outdoor air damper positions)<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Step 3 gather yet more detailed information when Step 2 results in more than 10% difference between annual and predicted energy plus worse than 75% R-squared correlation month-by-month.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Step 1 can be considered a measure of opportunity for the owner and is supposed to be very fast and inexpensive. Step 2 confirms and quantifies the opportunity, and includes a moderate amount of additional effort. Step 3 is even more effort and more costly.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think many owner / managers are hesitant to invest much money when they are unconvinced that there is any sizable opportunity / savings. Once it looks promising, they are more likely to fund additional work. More likely, but not highly likely, so that step still needs to be a modest cost increase.<o:p></o:p></span></p><p class=Default><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The just-delivered ASHRAE Journal has an interesting article on “Streamlining Energy Simulation To Identify Building Retrofits”, which is very timely for me </span><span style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>J</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>. The authors did a fairly detailed audit of a 700,000 sq.ft. Federal office building in ~300 hours. Check it out! I think we could have done better, but they seem to have done a very good job ;)<o:p></o:p></span></p><p class=Default><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal align=center style='text-align:center'><b><span style='font-size:13.5pt;font-family:"Calibri","sans-serif";color:#1F497D'>The Building Performance Team<br></span></b><b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>James V. Dirkes II, P.E., BEMP , LEED AP<br></span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>1631 Acacia Drive NW<br>Grand Rapids, MI 49504<br>616 450 8653<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>JP Beaulieu<br><b>Sent:</b> Monday, November 14, 2011 1:21 PM<br><b>To:</b> bldg-sim@lists.onebuilding.org<br><b>Subject:</b> Re: [Bldg-sim] Energy Models for Existing Buildings<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Hi Jim,<br>Here are my thoughts on the subject. That'll help me sort things out as well.<br><br>I don't do an audit without a full year hour by hour simulation. Why?<br>Because we offer E Audits as a means to optimise a client's building and to give all the details to the client in order for him to make a good decision. BTW, we do small and large commercial and institutionnal bldg simulations and have been using EnergyPlus for some time now.<br><br>I must say that the solutions we are proposing call for something flexible like EnergyPlus. I was using other softwares before but I must admit that there where times when there was little advantage of using simulation because we had to do the savings calculations on the side using much guessing or assumptions. Now I can make any system I like. Using bldg exhaust air or outdoor air or a mix of the two to feed the garage ventilation system would be easy and take out a lot of uncertainties. <br>I think that other softwares are fine if you just want to compare two systemes performances in a real life bldg in a specific climate and with specific uses. When I think of e-sim as a set of equipement (HVAC) for a specific bldg (walls and windows, etc.) used in a specific way by the occupants (schedules, plug loads, etc.) I realise that there is much more interpretation and uncertainties in the latter anyway. So why bother with hour by hour e-sim if you are not looking at what's happening every hour. <br>In optimisation however, I need to look at what's happening every hour. While most other softwares are running 8760 hours most do not give you a good visualisation of the results on that scale (i.e. hour by hour). I want to be able to graph a pumps runtime with a room's exess heat, concurrent cooling and heating loads, exhaust air of one room compared to the intake of another... This is why I use hour by hour e-sim. <br><br>You mention that you are looking for the big picture. I agree but...I tend to be carefull at not adding (and often multiplying) uncertainties. you know what I'm talking about. I think I change my strategy depending on the type of building use or construction. I won't be looking too much at the pumps if there are only a few. I might consider more the wall construction of an older bldg, But bottom line, why bother with a pump's specifications if you're not even sure of its runtime. What do you think?<br><br>Also, matching the bldg's energy bills helps me to validate some schedules and HVAC operations mainly. I don't really want to be close to the bills each time. 30% can be acceptable if you have some explanations. I look at the patterns of real vs simulation data : monthly energy use distribution by source and by end use, peak power demand monthly. I would like to use benchmarking more but I didn't find much valuable information for canadian bldgs yet. <br><br>Anyone has good BENCHMARKING data for canada? by end use mainly. <br>Energy Portfolio Manager (EPM) will now collaborate with Canada gov. I hope that is good. I used it once and had a major issue with source energy since the bldg was 100% electric. Electricity is 90+% hydro here in Montreal.<br><br>"How carefully must the energy model match define ECMs?"<br>I'd say how important are the results in making the right decision? also, what does it take to have more precise information? It's a tradeoff between the two.<br><br><o:p></o:p></p></div></body></html>