<HTML><BODY>Dear Eduardo<br /><br />two thoughts: <br /><br />a) The two numbers you give differ by approx. 0.2 percent. I would not say this is really far apart given that the approaches in calculation of the heat loss are most likely quite different.<br /><br />b) Have you tried to take the given "energy stored" into account in your comparison?<br /><br />I seem to remember that there is some information on the output in the CookBook. Have you taken a look there?<br /><br />Best<br />Achim<br /><br /><br /><br />--------- Original-Nachricht --------<br /> Von: "Eduardo Goncalves" <eduardo.llcg@gmail.com><br /> An: "esp-r@lists.strath.ac.uk" <esp-r@lists.strath.ac.uk><br /> Betreff: [esp-r] Amount of energy that passes through the surfaces<br /> Datum: 20/12/10 22:31<br /> <br /> <p style="text-align: justify; background: none repeat scroll 0% 0% white" class="MsoNormal"><span style="font-size: 12pt; line-height: 115%; font-famil!
y:
"Times New Roman","serif"">Hello ESP-r world,</span></p><p style="text-align: justify; background: none repeat scroll 0% 0% white" class="MsoNormal"><span style="font-size: 12pt; line-height: 115%; font-family: "Times New Roman","serif""><br /> </span></p> <p style="text-align: justify; background: none repeat scroll 0% 0% white" class="MsoNormal"><span style="font-size: 12pt; line-height: 115%; font-family: "Times New Roman","serif"">I Hope you can help me,</span></p> <p style="text-align: justify; line-height: normal; background: none repeat scroll 0% 0% white" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif"; background: none repeat scroll 0% 0% white">I am trying to determine the amount of energy that passes through a wall. I have a fairly simple model (square with 10x10 each side and 3m height). I have a basic control with 25 degrees the whole summer (!
June
till September), there are no internal gains from occupants or lights and I want to know the amount of gain/loss through the walls</span><span style="font-size: 12pt; font-family: "Times New Roman","serif"">.</span></p> <p style="text-align: justify; line-height: normal; background: none repeat scroll 0% 0% white" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif"">Once simulated, if I go through <em>Enquire about/Zone Energy Balance/Integrated over <span style="background: none repeat scroll 0% 0% white">time/Gain-Loss</span></em><span style="background: none repeat scroll 0% 0% white"> I have the following results,</span></span></p> <p class="MsoPlainText"><span style="font-family: "Courier New""> </span></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span>
</span><span> </span>Gain<span> </span>Loss</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Infiltration air load<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Ventilation air load<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Uncontr`d casual Occupt<span>
</span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Uncontr`d casual Lights<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Uncontr`d casual Equipt<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Thermal bridge (linear)<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier
New""><span> </span>Storage at air point<span> </span>0.925<span> </span>-0.977</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Opaque surf convec: ext<span> </span>233.485<span> </span>-16.093</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Opaque surf convec: ptn<span> </span>157.405<span> </span>-33.853</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Transp surf convec: ext<span> </span>0.000<span> </span>0.000</span></strong></p> <p
class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Transp surf convec: ptn<span> </span>0.000<span> </span>0.000</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Convec portion of plant<span> </span>44.617<span> </span>-385.509</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Totals<span> </span>436.433<span> </span>-436.433</span></strong></p> <p class="MsoNormal"><span> </span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12!
pt;
font-family: "Times New Roman","serif"">I suppose that the gains from the walls would be 233.485+157.405= 390.989 Whrs, and losses 16.093+33.853 = 49.946 Whrs. (there’s no other source of internal gain in the model).</span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif"">So far so good, nevertheless, if I go through <em>Surface energy balance/Integrated over <span style="background: none repeat scroll 0% 0% white">time/Gain-Loss/All Items</span></em><span style="background: none repeat scroll 0% 0% white">, I get something like,</span></span></p> <p class="MsoNormal"><span> </span></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span>
</span><span> </span>Facing Teste<span> </span>Facing outside</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Gain<span> </span>Loss<span> </span>Gain<span> </span>Loss</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Conductive flux<span> </span>111853.23<span> </span>-16240.70<span> </span>1745485.50 -1842903.13</span></strong></p> <p class="MsoPlainText"><strong><!
span
style="font-family: "Courier New""><span> </span>Convective flux<span> </span>3598.84<span> </span>-53664.82<span> </span>1333.83 -3128152.00</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Longwave rad int<span> </span>15327.17<span> </span>-60134.77<span> </span>--<span> </span>--</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>LW rad ext >bldg<span> </span>--<span> </span>--<span> </span>476125.97<span> </span>-244280.39</span></strong></p> <p class="MsoPlainText"><stron!
g><span
style="font-family: "Courier New""><span> </span>LW rad ext >sky<span> </span>--<span> </span>--<span> </span>0.00 -2835801.50</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>LW rad ext >grnd<span> </span>--<span> </span>--<span> </span>27968.51<span> </span>-643154.69</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Shortwave rad.<span> </span>0.00<span> </span>0.00<span>
</span>6443323.00<span> </span>0.00</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Occupt casual gn<span> </span>0.00<span> </span>0.00<span> </span>--<span> </span>--</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Lights casual gn<span> </span>0.00<span> </span>0.00<span> </span>--<span> </span>--</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier
New""><span> </span>Equipt casual gn<span> </span>0.00<span> </span>0.00<span> </span><span> </span>--<span> </span>--</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Controled casual<span> </span>0.00<span> </span>0.00<span> </span>--<span> </span>--</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Heat stored<span> </span>15333.66<span> </span>-16072.75<span>
</span>720997.19<span> </span>-720940.69</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Plant<span> </span>0.00<span> </span>0.00<span> </span>0.00<span> </span>0.00</span></strong></p> <p class="MsoPlainText"><strong><span style="font-family: "Courier New""><span> </span>Totals<span> </span>146112.91<span> </span>-146113.05<span> </span>9415234.00 -9415233.00</span></strong></p> <p class="MsoNormal"><span> </span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New
Roman","serif"">for each surface of the model (4 walls, ceiling and pavement). </span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif"">Having those values for each surface, I sum the losses of the surface facing inside (<strong>392043Whrs</strong>), which would be the convective heat that is transferred to the zone, i.e., gain and losses that comes from the <em>Zone energy balance</em>, as referred <span style="background: none repeat scroll 0% 0% white">to initially (Gain <strong>390,989 kWhrs</strong>, and losses 49946 Whrs). The problem is that the</span> results are <strong>very</strong> different <strong>(392043Whrs/390989kWhs)</strong>, and I don’t know why. My suppositions must be wrong.</span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New
Roman","serif"">How can I actually get the amount of energy that passes through the walls (gains and losses)? <br /></span></p><p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif""><br /> </span></p> <p style="text-align: justify; line-height: normal" class="MsoNormal"><span style="font-size: 12pt; font-family: "Times New Roman","serif"">Thanks for your help</span></p> -- <br />Eduardo Gonçalves<br />+ 351 913 310 390<br /> <br /> <br /> <hr /> <br /> _______________________________________________<br /> esp-r mailing list<br /> <a href="mailto:esp-r@lists.strath.ac.uk" class="autolink">esp-r@lists.strath.ac.uk</a><br /> <a href="http://lists.strath.ac.uk/mailman/listinfo/esp-r" target="_blank" class="autolink">http://lists.strath.ac.uk/mailman/listinfo/esp-r</a></BODY></HTML>