<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 12 (filtered medium)"><!--[if !mso]><style>v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style><![endif]--><style><!--
/* Font Definitions */
@font-face
{font-family:"MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:"Stylus BT";
panose-1:2 14 4 2 2 2 6 2 3 4;}
@font-face
{font-family:"\@MS Mincho";
panose-1:2 2 6 9 4 2 5 8 3 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
p.MsoAcetate, li.MsoAcetate, div.MsoAcetate
{mso-style-priority:99;
mso-style-link:"Balloon Text Char";
margin:0in;
margin-bottom:.0001pt;
font-size:8.0pt;
font-family:"Tahoma","sans-serif";}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.BalloonTextChar
{mso-style-name:"Balloon Text Char";
mso-style-priority:99;
mso-style-link:"Balloon Text";
font-family:"Tahoma","sans-serif";}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="2050" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</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'>John et al:<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'>The query seems to be branching out pretty quickly … I have many thoughts on the broader topic and present state of LED’s and their that wouldn’t make everyone happy to read/hear, but I think this addresses the heart of John’s post directly:<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'>The problem of lights as an internal heat load remains pretty simple for us energy modelers and HVAC designers, and isn’t made more difficult by LED technology. <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'>Consider a light fixture of any source as the boundaries of a thermodynamic problem: Energy in = Energy out. If we put 100W of energy into the fixture, then 100W of energy must be produced in some form. That output is some combination of visible light energy that our eyeballs can perceive, and invisible other energy which can largely be perceived as heat/sound after transmitting through the air or other surfaces to arrive our eardrums/skin. Normally that ratio of output visible light energy is tiny, but for certain LED sources it’s less tiny**. That fraction is entirely moot however from an building energy simulation standpoint. All energy output in the form of light will encounter surfaces (floors/walls/people) and ultimately be absorbed*. In the process, the energy will briefly excite a few electrons… but when the lights go off and the excited electron-party is over all that’s left is energy irradiated an invisible wavelengths (excepting glow-in-the-dark t-shirts). The big point here is, energy input is the only figure/variable we really care about, because that’s exactly the amount of energy we need to consider from an HVAC heating/cooling perspective. None of it just goes away. <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'>~Nick<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'>* Acknowledging: A fraction of light hitting exterior windows transmits out of a building – I’ll claim this negligible since that’s a fraction (glass transmittance) of a fraction (window to every-other-surface ratio) of an already small fraction of the input watts (visible light vs. other wavelengths).<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'>** If anyone cares to better understand this careful choice of words, or wishes to better cut through marketing mis-information from the lighting industry, I would first advise taking some time to review difference in the terms ‘efficacy’ & ‘efficiency,’ then identify the contextual mis-use in the preceding discussion below. Incorrect conclusions regarding heat are made as a result. A hint: Both can use units of “lumens per watt” in the right context, but lumens per watt of light output is not the same thing as lumen of light output per watt of input energy ;).<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><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><img width=119 height=37 id="Picture_x0020_1" src="cid:image001.jpg@01CC84E5.49871AF0" alt="cid:489575314@22072009-0ABB"></span><b><span style='font-size:11.0pt;font-family:"Stylus BT","sans-serif";color:#2D4D5E'><o:p></o:p></span></b></p><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Stylus BT","sans-serif";color:#2D4D5E'><o:p> </o:p></span></b></p><p class=MsoNormal><b><span style='font-family:"Stylus BT","sans-serif";color:#2D4D5E'>NICK CATON, P.E.</span></b><b><span style='font-family:"Stylus BT","sans-serif";color:#2D4D5E'><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Calibri","sans-serif";color:#CC9900'>SENIOR ENGINEER<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Calibri","sans-serif";color:#CC9900'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2D4D5E'>Smith & Boucher Engineers</span><span style='font-size:7.5pt;color:#CC9900'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2D4D5E'>25501 west valley parkway, suite 200<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2D4D5E'>olathe, ks 66061<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2D4D5E'>direct 913.344.0036<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2D4D5E'>fax 913.345.0617<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><a href="www.smithboucher.com" title="blocked::www.smithboucher.com"><span style='font-size:10.0pt'>www.smithboucher.com</span></a></span><u><span style='font-size:10.0pt;font-family:"Calibri","sans-serif";color:blue'> </span></u><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Charles Holleran<br><b>Sent:</b> Friday, October 07, 2011 10:49 AM<br><b>To:</b> john.s.eurek@usace.army.mil; equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] LED Lights (UNCLASSIFIED)<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>LED's use DC power, and do so efficiently. Sounds like you're referring to the AC-to-DC power supply though, not the LED light source itself.<br> <br>As described in your post below ACDC power converters can be loosely lumped into 2 categories:<br>- old, inefficient, big, hot, LINEAR converters with their big transformers, and<br>- newer smaller, cooler, SWITCHING converters ("the cool kind" referred to below)<br> <br>I think Enerstar has done a lot to phase out the inefficient LINEAR converters. You can still procure the LINEAR power supplies. But you probably won't find one that meets Enerstar requirements. The SWITCHING supplies are much more efficient, and may even cost less now, as they are smaller, lighter, and have less metal in them.<br> <br>So here's a couple of Enerstar links for some reference material:<br><a href="http://www.energystar.gov/index.cfm?c=archives.power_supplies">http://www.energystar.gov/index.cfm?c=archives.power_supplies</a><br><a href="http://www.energystar.gov/ia/partners/product_specs/program_reqs/eps_prog_req.pdf">http://www.energystar.gov/ia/partners/product_specs/program_reqs/eps_prog_req.pdf</a><br> <br>For more information on SWITCHING ac to dc supplies:<br><a href="http://en.wikipedia.org/wiki/Power_supply#AC.2FDC_supply">http://en.wikipedia.org/wiki/Power_supply#AC.2FDC_supply</a><br> <br>The Wiki article gives some ideas as to the "magic" that is achieved with the new supplies.<br> <br>If the question was about the LED's themselves and not the transformers/converters that go with them then please excuse my sidetrack.<br> <br>If anyone has seen central DC converters wired throughout the facility I'd be very interested to hear about it. Certainly many loads are now DC. Perhaps the Tesla Wars (<a href="http://en.wikipedia.org/wiki/War_of_Currents">http://en.wikipedia.org/wiki/War_of_Currents</a>) are swinging back towards Edison for efficiency reasons.<br> <br>Charlie Holleran<br>Holleran Technologies<br><a href="mailto:scorpdaddy@hotmail.com">scorpdaddy@hotmail.com</a><br> <br><br> <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>> Date: Fri, 7 Oct 2011 09:27:55 -0500<br>> From: John.S.Eurek@usace.army.mil<br>> To: equest-users@lists.onebuilding.org<br>> Subject: [Equest-users] LED Lights (UNCLASSIFIED)<br>> <br>> Classification: UNCLASSIFIED<br>> Caveats: NONE<br>> <br>> All,<br>> <br>> Are LED lights really magical? We have all used a laptop and felt the AC/DC<br>> converter get hot. We know that if a transformers (not the cool kind) are<br>> inside a building they put off a lot of heat. What about the transformers<br>> for the LED lights?<br>> <br>> LED lights need DC power, where are all the transformers and were does that<br>> heat go?<br>> <br>> I suspect the LED light is like the electric car. It is cool that the car<br>> runs off of electricity, just don't look at the coal that is burnt to make<br>> the electricity. Yes LED lights give off almost no heat, but what about the<br>> transformer?<br>> <br>> Anybody have any information on this? What is the heat of rejection from the<br>> transformers.... (I have done a little research and one solution was to have<br>> a single transformer for the building and wire the lighting of the building<br>> with DC power. Talk about changing business as usual.)<br>> <br>> <br>> John Eurek <br>> <br>> -----Original Message-----<br>> From: equest-users-bounces@lists.onebuilding.org<br>> [mailto:equest-users-bounces@lists.onebuilding.org] On Behalf Of John Bixler<br>> Sent: Thursday, October 06, 2011 8:25 AM<br>> To: Taylor Sharpe; equest-users@lists.onebuilding.org<br>> Subject: Re: [Equest-users] Lighting densities and Electricalequipment<br>> contributing to Space Heating<br>> <br>> Taylor,<br>> <br>> <br>> <br>> A number of things play into the question you are asking.<br>> <br>> <br>> <br>> * Different types of lighting have different efficiencies.<br>> Incandescent lights create a lot of heat, LEDs create practically no heat.<br>> Fluorescent is somewhere in between but create much less heat then<br>> incandescent<br>> <br>> * The style of light installed - is it pendant hung in the space? If<br>> so, 100% of the created heat is given to the space. Is it recessed? If so,<br>> a portion of the heat is given to the plenum, and some of the heat given to<br>> the plenum leaves the building as relief air (in fact, it's possible that all<br>> the plenum heat leaves the building in the case of a 100% outdoor air system)<br>> <br>> * The schedule of the lights. Were you looking at yearly consumption<br>> or peak heating load? Peak heating load is typically calculated with the<br>> lights (and occupancy and misc loads) at 0%. If you were looking at yearly<br>> consumption, but your modeled facility has the lights turned off for a<br>> majority of the time, the impact may be minimized.<br>> <br>> <br>> <br>> Point being, you have to consider more than just lighting density when you<br>> make this analysis. <br>> <br>> <br>> <br>> John Bixler, EIT, LEED AP BD+C<br>> <br>> Mechanical Designer<br>> <br>> Sebesta Blomberg <br>> sebesta.com | P 319.364.1005 | M 319.558.9299 <br>> <br>> <br>> <br>> This message has been sent via the Internet. Internet communications are not<br>> secure against interception or modification. Sebesta Blomberg therefore can<br>> not guarantee that this message has not been modified in transit. This<br>> message and any files transmitted with it are confidential and intended<br>> solely for the use of the addressee. If you have received this message in<br>> error please notify the sender and destroy your copies of the message and any<br>> attached files.<br>> <br>> <br>> <br>> <br>> <br>> <br>> <br>> From: equest-users-bounces@lists.onebuilding.org<br>> [mailto:equest-users-bounces@lists.onebuilding.org] On Behalf Of Taylor<br>> Sharpe<br>> Sent: Wednesday, October 05, 2011 10:18 PM<br>> To: John Bixler<br>> Subject: [Equest-users] Lighting densities and Electrical equipment<br>> contributing to Space Heating<br>> <br>> <br>> <br>> Hi everyone,<br>> <br>> I feel that this topic must have been discussed at some point, but an<br>> exhaustive archive search got me nowhere, so I thought I'd throw together a<br>> post of my own, especially since I'm working on an eQuest model of a small<br>> server building which is heated in part by a large number of computers that<br>> run many hours every day.<br>> <br>> I'm interested in how eQuest treats electric loads - from lights, computers,<br>> refrigerators, etc - as regards space heating. I had always assumed that,<br>> especially in the case of lights, much of the energy used would be converted<br>> to heat within the building, and contribute to space heating.<br>> <br>> However, I set up an experiment to test this and found that the results were<br>> far different from what I'd expected: I upped the lighting density in an<br>> existing natural-gas-heated building model by about 15x and compared the<br>> electric use from before and after the lights were increased. I converted<br>> all values to mmBtus for easy comparison. To my surprise, I found that only<br>> a very small fraction (about 6%) of the mmBtus added to the building through<br>> those lights contributed to space heat. The kWh recorded were increased<br>> hugely, but the heating energy required to keep the building heated was<br>> almost the same in both cases.<br>> <br>> I repeated the experiment, upping misc. equipment instead of lighting, and<br>> saw a similar result.<br>> <br>> Does anyone have any knowledge of what equations eQuest uses to decide how<br>> much electrical energy use is converted to heat and added to the space in<br>> which it is installed?<br>> <br>> Regards,<br>> Taylor Sharpe<br>> Sharpe Energy Solutions<br>> newspectrum@gmail.com<br>> (541-840-5698)<br>> <br>> <br>> Classification: UNCLASSIFIED<br>> Caveats: NONE<br>> <br>> <br>> _______________________________________________<br>> Equest-users mailing list<br>> http://lists.onebuilding.org/listinfo.cgi/equest-users-onebuilding.org<br>> To unsubscribe from this mailing list send a blank message to EQUEST-USERS-UNSUBSCRIBE@ONEBUILDING.ORG<o:p></o:p></span></p></div></div></div></body></html>