<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 14 (filtered medium)"><style><!--
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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='color:#1F497D'>I had a question yesterday regarding heat transfer through interior walls. I think this comes up on the list fairly frequently – why is my LS-C (or LS-B) report showing no heat transfer across internal surfaces when I know my garage or attic is colder than the adjacent spaces. Is this heat loss really being reflected in the model – and if so, why isn’t it in the LOADS reports?<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Here was my answer – (corrections & clarifications are welcome):<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>What you are doing to model the effect of insulating the floor between the garage and the ground level is correct. eQUEST will calculate the heat loss across that</span><span style='color:#1F497D'> interior surface</span><span style='color:#1F497D'> floor and show the impact of the insulation. The main issue is finding it. I imagine you are looking at the LS-C or LS-B report which show no internal conduction. The issue here is how the calculations are sequenced in DOE-2. In the LOADS, we are calculating the envelope heat loss then in SYSTEMS we are calculating the HVAC response. But, until the HVAC response is calculated, we don’t know what the space temperature is so we can’t calculate the envelope heat loss as we don’t know the delta-T between inside and outside. So, for LOADS, we give the space temperature an initial guess – keyword Temperature in the SPACE. By default, all spaces have their temperature set to 70F – this is why you see no internal heat loss in the LS- LOADS reports as the temperature is the same for all zones. You could set the annual average temperature down in the garage so that the heat loss shows here but it is not that important. As long as in the zones, the keyword SIZING-OPTION is set to ADJUST</span><span style='color:#1F497D'>-</span><span style='color:#1F497D'>LOADS then in SYSTEMS, the actual space temperature will be used to recalculate the heat loss. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>So, the heat loss is there – you can reassure yourself of this by creating an interior wall of nearly infinite resistance, apply it as a parametric run, and see the space heating in the adjacent zones go down. You can also create hourly reports that look at the parameters of the zones. One of the hourly variables (23) at the zonal level is “Contrib to the zone load due to conduction from adj zones (Btu/hr)” -- this is where you will see the actual hourly heat loss using the actual hourly space temperature for the zones.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I hope this helps clear up what you are seeing. Please feel free to ask more if I am not being clear.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Kind regards,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Brian<o:p></o:p></span></p></div></body></html>