<font size="3" face="Times New Roman">
</font><div style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3"><font face="Calibri">Hi all,</font></font></span></div><div style="margin: 0in 0in 0pt;" class="MsoNormal">
<span style="color: rgb(31, 73, 125);"></span> </div><div style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3"><font face="Calibri">In the UK when modeling houses,
for example, the reduction in infiltration provides a much bigger return on the
overall energy saving – albeit with a much simpler model engine. Let me
explain.</font></font></span></div><font size="3" face="Times New Roman">
</font><p style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3" face="Calibri"> </font></span></p><font size="3" face="Times New Roman">
</font><p style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3"><font face="Calibri">British Building Regulations
demand a maximum infiltration rate of 10m³ /h.m² of wall area (at 50pa) –
equivalent to a little over a hole the size of a 5 peso coin per m².
Reducing the infiltration rate to 3m³ gets an instant improvement in overall
energy consumption of around 3%. Further, Germany’s Passivhaus criteria
has a maximum heating demand of 15kWh/m².yr – ditto cooling demand.
To achieve that they regularly build to infiltration not exceeding
1m³. That’s difficult to achieve but the point is I don’t see anywhere
near the percentage improvements from similar ‘tests’ with infiltration with
the DOE models. Why is that?</font></font></span></p><font size="3" face="Times New Roman">
</font><p style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3" face="Calibri"> </font></span></p><font size="3" face="Times New Roman">
</font><font size="3" face="Times New Roman">
</font><span style="color: rgb(31, 73, 125);"><font size="3"><font face="Calibri">Thanks in advance!</font></font></span><div style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3" face="Calibri"></font></span> </div>
<div style="margin: 0in 0in 0pt;" class="MsoNormal"><span style="color: rgb(31, 73, 125);"><font size="3" face="Calibri">-Robert</font></span></div><font size="3" face="Times New Roman">
</font><br><br><div class="gmail_quote">On Thu, Aug 11, 2011 at 2:04 AM, Eurek, John S NWO <span dir="ltr"><<a href="mailto:John.S.Eurek@usace.army.mil" target="_blank">John.S.Eurek@usace.army.mil</a>></span> wrote:<br>
<blockquote style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;" class="gmail_quote">
Classification: UNCLASSIFIED<br>
Caveats: NONE<br>
<br>
<br>
Another infiltration issue to consider is the infiltration schedule. Most of<br>
my designs include building pressurization during occupied hours. I make an<br>
infiltration schedule and set the infiltration to 10% during occupied hours.<br>
<br>
The biggest advantage is that all the outside air goes through an energy<br>
recovery unit and therefore is tempered.<br>
<br>
<br>
<br>
"Is Freedom a small price to pay to stop Global Warming?"<br>
<br>
John Eurek PE, LEED AP<br>
<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of Robby Oylear<br>
Sent: Wednesday, August 10, 2011 11:55 AM<br>
To: Mehta, Gaurav<br>
Cc: <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
Subject: Re: [Equest-users] Basic stuff - Infiltration<br>
<br>
Gaurav's screenshot didn't come through for me, so to summarize, in order to<br>
take wind-speed correction factors into account you need to take the value of<br>
INF-FLOW/AREA that the wizard inputs into the detailed file and convert it to<br>
an AIR-CHANGE/HR value. eQUEST does not apply wind-speed correction to<br>
INF-FLOW/AREA (see below).<br>
<br>
>From DOE-2 help file on INF-METHOD:<br>
<br>
AIR-CHANGE<br>
<br>
The infiltration rate is calculated using the air-change method.<br>
AIR-CHANGES/HR or INF-FLOW/AREA should be specified if INF-METHOD =<br>
AIR-CHANGE. In this case the value AIR-CHANGES/HR will be corrected for wind<br>
speed each hour, but the value of INF-FLOW/AREA will not be corrected. If<br>
both AIR-CHANGES/HR and INF-FLOW/AREA are specified, the resulting<br>
infiltration rates are added.<br>
<br>
<br>
On Wed, Aug 10, 2011 at 9:50 AM, Mehta, Gaurav <<a href="mailto:Gaurav.Mehta@stantec.com" target="_blank">Gaurav.Mehta@stantec.com</a>><br>
wrote:<br>
<br>
<br>
Here is a recent response that I posted on Bldg-Sim.<br>
<br>
<br>
<br>
Gaurav Mehta, LEED® AP BD+C<br>
Sustainable Building Analyst<br>
Stantec<br>
<br>
1932 First Avenue Suite 307<br>
Seattle WA 98101<br>
Ph: <a href="tel:%28206%29%20770-7779" target="_blank" value="+12067707779">(206) 770-7779</a> <tel:%28206%29%20770-7779><br>
Fx: <a href="tel:%28206%29%20770-5941" target="_blank" value="+12067705941">(206) 770-5941</a> <tel:%28206%29%20770-5941><br>
<a href="mailto:Gaurav.Mehta@stantec.com" target="_blank">Gaurav.Mehta@stantec.com</a><br>
<br>
<a href="http://stantec.com" target="_blank">stantec.com</a> <<a href="http://www.stantec.com" target="_blank">http://www.stantec.com</a>><br>
<br>
<br>
<br>
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From: <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of Nick Caton<br>
Sent: Wednesday, August 10, 2011 9:40 AM<br>
To: Robby Oylear; John Bixler<br>
Cc: <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<br>
<br>
Subject: Re: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
<br>
<br>
Robby - awesome post, thanks for linking that paper!<br>
<br>
<br>
<br>
As an extra heads up/thought: depending on which infiltration method<br>
is selected, I do believe eQuest will also calculate hourly infiltration<br>
rates working from windspeed in the weather file. Details would be in the<br>
help files... I can't recall if this happens with the default method, or if<br>
there is a single "default" method (it might vary based on how you define<br>
infiltration at the wizard level?)...<br>
<br>
<br>
<br>
~Nick<br>
<br>
<br>
<br>
cid:489575314@22072009-0ABB<br>
<br>
<br>
<br>
NICK CATON, P.E.<br>
<br>
SENIOR ENGINEER<br>
<br>
<br>
<br>
Smith & Boucher Engineers<br>
<br>
25501 west valley parkway, suite 200<br>
<br>
olathe, ks 66061<br>
<br>
direct <a href="tel:913.344.0036" target="_blank" value="+19133440036">913.344.0036</a><br>
<br>
fax <a href="tel:913.345.0617" target="_blank" value="+19133450617">913.345.0617</a><br>
<br>
<a href="http://www.smithboucher.com" target="_blank">www.smithboucher.com</a> <<a href="http://www.smithboucher.com" target="_blank">http://www.smithboucher.com</a>><br>
<br>
<br>
<br>
From: Robby Oylear [mailto:<a href="mailto:robbyoylear@gmail.com" target="_blank">robbyoylear@gmail.com</a>]<br>
Sent: Wednesday, August 10, 2011 11:28 AM<br>
To: John Bixler<br>
Cc: Nick Caton; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
Subject: Re: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
John,<br>
<br>
<br>
<br>
The infiltration as a function of exterior gross wall area is only<br>
available in the wizard. I don't believe DOE2.2 is capable of having inputs<br>
that relate to the sum of a parameter of it's child components. The DOE2.2<br>
BDL Functions do not have any references to child components (i.e. a Wall can<br>
reference a parameter of its parent Space, but a Space cannot reference a<br>
parameter of its child Wall).<br>
<br>
<br>
<br>
Regarding Lawrence's initial question about converting a known tested<br>
value to a value usable within eQUEST, the PNNL Report 18898, Infiltration<br>
Modeling Guidelines for Commercial Building Energy Analysis<br>
(<a href="http://www.pnl.gov/main/publications/external/technical_reports/PNNL-18898.pdf" target="_blank">http://www.pnl.gov/main/publications/external/technical_reports/PNNL-18898.p<br>
df</a>) contains formula for converting infiltration from a test case to an<br>
actual design case. Based on the example presented in the document, a<br>
conversion factor of 0.112 can be derived.<br>
<br>
<br>
<br>
So a tested air leakage of 0.40 CFM/SF at 0.30 in. w.g. would be<br>
modeled at 0.045 CFM/SF. This value is modeled at 100% when building fan<br>
system is off and 25% when the building fan system is on.<br>
<br>
<br>
<br>
Granted, this may be an oversimplification for eQUEST, as the<br>
document was written for EnergyPlus which contains a wind-driven infiltration<br>
model, but it seems to be a good starting point at least if you have test<br>
information available.<br>
<br>
<br>
<br>
Robby Oylear, LEED® AP BD+C<br>
<br>
Mechanical Project Engineer<br>
<br>
Energy Analyst<br>
<br>
<br>
<br>
D <a href="tel:206-788-4571" target="_blank" value="+12067884571">206-788-4571</a> | C <a href="tel:206-354-2721" target="_blank" value="+12063542721">206-354-2721</a><br>
<br>
<a href="http://www.rushingco.com" target="_blank">www.rushingco.com</a> <<a href="http://www.rushingco.com/" target="_blank">http://www.rushingco.com/</a>><br>
<br>
<br>
<br>
<br>
<br>
On Wed, Aug 10, 2011 at 8:17 AM, John Bixler <<a href="mailto:JBixler@sebesta.com" target="_blank">JBixler@sebesta.com</a>><br>
wrote:<br>
<br>
Thanks for the response Nick.<br>
<br>
<br>
<br>
As I recall from a recent foray into this subject in eQuest (in<br>
detailed mode), the cfm/sq ft entry is based on floor area.<br>
<br>
<br>
It would be logical that if cfm/sq ft of exterior wall is an option<br>
in wizard mode, it would also be an option in detailed mode - I just haven't<br>
dug that far yet.<br>
<br>
<br>
<br>
From: Nick Caton [mailto:<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>]<br>
Sent: Wednesday, August 10, 2011 10:08 AM<br>
To: John Bixler; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
Subject: RE: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
Hi John - thanks for your thoughts!<br>
<br>
<br>
<br>
I was relating some of the same concerns with others off-list ... I'm<br>
am no infiltration-auditing expert (though some lurk among us here on the<br>
lists ^_~), but one thing I can say based on my past attempts to build a<br>
better mousetrap regarding infiltration is that where ASHRAE may be generally<br>
vague on the topic - they are actually doing a lot to say (if not always<br>
directly) that whole building infiltration is a very difficult thing to<br>
quantify at best (sorry for excessive use of parentheticals (I mean it!)...).<br>
<br>
<br>
<br>
The best guidance imaginable that would still be practical in<br>
day-to-day use would have to rely in some part on subjective observations<br>
(guesses) regarding envelope constructions. Two brick walls of certain<br>
grout/masonry ratios weathered for the same period in the same climate may<br>
still have different leakiness because the two masons used slightly different<br>
grout mixes... What I'm getting at is you couldn't realistically construct a<br>
table that covered every variable, and many variables are not "knowable."<br>
<br>
<br>
<br>
That's not to say the residential ACH table isn't useful for<br>
subjective estimations, nor that research couldn't be undertaken to raise the<br>
bar a notch. As John is alluding, a table providing representative<br>
commercial envelope constructions (with accompanying illustrations!) and/or<br>
layer combinations could be undertaken that would provide infiltration<br>
performance as a function of time. Values could be given for new<br>
construction, and after weathering for 1/5/10 years. While new<br>
constructions/layers could be assessed in a controlled environment, initial<br>
research on aged constructions would need to be done sampling within a single<br>
climate zone. Separate/concurrent research could explore determining<br>
multipliers on the weathering effects based on varying climate and<br>
geography... All things being equal, a beachside wall built in Miami, FL<br>
with lots of sun/salt/torrential rain seasons and the occasional hurricane<br>
will weather differently over a decade than the same wall in a milder<br>
climate. The net result of such research could ultimately produce some<br>
really helpful tools in better assessing existing and new constructions for a<br>
variety of industries and purposes (energy modeling included).<br>
<br>
<br>
<br>
Considering the growing presence and pressing need for better tools<br>
in the world of energy modeling, I would put forward prime candidates for<br>
whole construction assemblies would be ASHRAE 90.1 baseline constructions as<br>
defined in Appendix A.<br>
<br>
<br>
<br>
For all I know, such research may be underway or completed years ago<br>
- my ear is not quite so close to the ground with the academic world... can<br>
anyone comment?<br>
<br>
<br>
<br>
<br>
<br>
To another point you brought up - eQuest is quite capable of using<br>
your personally developed CFM/ft2 values - in the wizards even! In detailed<br>
mode you'll find there are inputs for more involved estimations as well if<br>
you wish to pursue other methods:<br>
<br>
Error! Filename not specified.<br>
<br>
Error! Filename not specified.<br>
<br>
<br>
<br>
Error! Filename not specified.<br>
<br>
<br>
<br>
NICK CATON, P.E.<br>
<br>
SENIOR ENGINEER<br>
<br>
<br>
<br>
Smith & Boucher Engineers<br>
<br>
25501 west valley parkway, suite 200<br>
<br>
olathe, ks 66061<br>
<br>
direct <a href="tel:913.344.0036" target="_blank" value="+19133440036">913.344.0036</a><br>
<br>
fax <a href="tel:913.345.0617" target="_blank" value="+19133450617">913.345.0617</a><br>
<br>
<a href="http://www.smithboucher.com" target="_blank">www.smithboucher.com</a> <<a href="http://www.smithboucher.com" target="_blank">http://www.smithboucher.com</a>><br>
<br>
<br>
<br>
From: <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of John Bixler<br>
Sent: Wednesday, August 10, 2011 9:23 AM<br>
To: <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
Subject: Re: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
My own personal opinion is that ASHRAE Fundamentals has not rescued<br>
us here.<br>
<br>
<br>
<br>
As Nick mentioned, the data presented there is for residential houses<br>
and relies on incredibly vague and subjective judgment calls by the modeler.<br>
<br>
<br>
<br>
Furthermore, the values presented are in the unit's of air changes<br>
per hour. To me, this is a terrible way to use the data. Your entries for<br>
infiltration then rely on the volume of the room to determine the amount of<br>
infiltration. The volume of the room (zone is probably a better term) has<br>
NOTHING to do with the infiltration. What if I have a gym that's<br>
150'x100'x50' tall, but it only has 10' wide by 50' tall of exterior wall???<br>
If I use the ASHRAE method and rely on air changes per hour, the zone will be<br>
modeled with a HUGE GIGANTIC REALLY REALLY LARGE amount of infiltration.<br>
<br>
<br>
<br>
Yet this seems to be the only recourse we have that is grounded in<br>
any sort of defendable data.<br>
<br>
<br>
<br>
I have looked and looked for a reliable report or other source for<br>
real world commercial/institutional construction infiltration values to no<br>
avail. It would be so incredibly useful.<br>
<br>
<br>
<br>
I have, over the course of my energy modeling career, developed a set<br>
of seemingly practical infiltration values to use, using the units of "CFM<br>
per sq ft of gross external wall area" available in Trane Trace (I don't<br>
believe these units are an option in eQuest). These values were developed by<br>
taking a number of buildings with no infiltration and arbitrarily adding<br>
infiltration in, until I get a reasonable utility consumption value. Hardly<br>
scientific and no way could I defend these values if they came under<br>
scrutiny, other than to say "well, you got a better idea????"<br>
<br>
<br>
<br>
Some may say "Eh, who cares about infiltration anyway?". Well, it<br>
makes a bigger difference then you'd think.<br>
<br>
<br>
<br>
A novice user who relies on the ASHRAE air changes per hour is likely<br>
significantly oversizing their cooling equipment in large rooms (ie<br>
conference, assembly, gyms, etc) which is exactly where you don't want to be<br>
oversizing cooling equipment.<br>
<br>
<br>
<br>
Think about the components of a heating load - envelope conduction<br>
losses, taking in cold OA...and infiltration. Envelope losses are generally<br>
small, the design community likes to temper their OA (rightfully so), so<br>
where is a major component of the heating (consumption) load coming from?<br>
Infiltration really adds up.<br>
<br>
<br>
<br>
How do you justify replacing leaky, wood sash windows? How bout<br>
making a switch to spray foam insulation? How about modeling door seals?<br>
<br>
<br>
<br>
I've rambled enough. Point being, we all are forced to use arbitrary<br>
numbers for something that is a significant component of both equipment<br>
sizing and energy modeling and it just makes me mad and embarrassed when I<br>
have to explain to a client or colleague "well those are really important,<br>
but completely imaginary, numbers..."<br>
<br>
<br>
<br>
From: <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of Bruce<br>
Easterbrook<br>
Sent: Tuesday, August 09, 2011 5:41 PM<br>
To: John Bixler<br>
Subject: Re: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
Since 1922!<br>
Bruce Easterbrook P.Eng.<br>
Abode Engineering<br>
ASHRAE Member<br>
<br>
On 09/08/2011 06:11 PM, lawrence Lile wrote:<br>
<br>
Good ol ASHRAE Fundamentals! Why didn't I think of looking there?<br>
Thanks!<br>
<br>
<br>
<br>
<br>
<br>
On Mon, Aug 8, 2011 at 11:36 AM, Nick Caton <<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>><br>
wrote:<br>
<br>
Hi Lawrence,<br>
<br>
<br>
<br>
My copy of ASHRAE Principles of HVAC includes a table (5-1) excerpted<br>
from ASHRAE Fundamentals, 2001 (Table 7, Ch 28). This table provides air<br>
change rates as a function of subjective envelope airtightness ("tight" /<br>
"medium" / "loose") and as a function of the outdoor design temperature.<br>
Upon reviewing the referenced Fundamentals chapter, I learned this table is<br>
built from research surveying residential homes of various vintages, so it<br>
helps to know that these are "tight" to "loose" residential constructions.<br>
<br>
<br>
<br>
In any case, I've used and cited this resource before when modeling<br>
infiltration and calculating sizing loads for non-residential projects as<br>
well. I've searched, but have yet to come up with an equivalent table based<br>
on surveying and measuring commercial constructions from a<br>
subjective/objective standpoint... That might be handier, but in the meantime<br>
this is a good tool for "converting" your subjective observations into the<br>
right ballpark.<br>
<br>
<br>
<br>
~Nick<br>
<br>
<br>
<br>
Error! Filename not specified.<br>
<br>
<br>
<br>
NICK CATON, P.E.<br>
<br>
SENIOR ENGINEER<br>
<br>
<br>
<br>
Smith & Boucher Engineers<br>
<br>
25501 west valley parkway, suite 200<br>
<br>
olathe, ks 66061<br>
<br>
direct <a href="tel:913.344.0036" target="_blank" value="+19133440036">913.344.0036</a><br>
<br>
fax <a href="tel:913.345.0617" target="_blank" value="+19133450617">913.345.0617</a><br>
<br>
<a href="http://www.smithboucher.com" target="_blank">www.smithboucher.com</a> <<a href="http://www.smithboucher.com" target="_blank">http://www.smithboucher.com</a>><br>
<br>
<br>
<br>
From: <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] On Behalf Of lawrence<br>
Lile<br>
Sent: Sunday, August 07, 2011 12:50 PM<br>
<br>
<br>
To: <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<br>
Subject: [Equest-users] Basic stuff - Infiltration<br>
<br>
<br>
<br>
In building modeling programs one always has to provide precise<br>
values for infiltration. In the real world, I will know one of two things:<br>
almost nothing (The building appears to be kinda leaky with old windows), or<br>
I will have a blower door test done at a specific pressure. How do I convert<br>
subjective ("kinda leaky") or objective (Blower door test) leakage into<br>
numbers that make sense in the program? Is there a guide one can use?<br>
<br>
<br>
<br>
<br>
<br>
--Lawrence<br>
<br>
<br>
<br>
<br>
<br>
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---------- Forwarded message ----------<br>
From: "Mehta, Gaurav" <<a href="mailto:Gaurav.Mehta@stantec.com" target="_blank">Gaurav.Mehta@stantec.com</a>><br>
To: "<a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a>" <<a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a>><br>
Date: Tue, 2 Aug 2011 11:12:31 -0600<br>
Subject: Re: [Bldg-sim] RE : Infiltration effect in Climate 1<br>
<br>
<br>
Richard,<br>
<br>
<br>
<br>
Are you using the default infiltration rate (0.038 cfm/ft2 of<br>
external wall area) for the perimeter spaces?<br>
<br>
<br>
<br>
eQUEST calculates the cfm based on the external wall area and then<br>
converts this to an infiltration flow (cfm/ft2 of floor area of the space).<br>
<br>
<br>
<br>
As Fredrick has pointed out this infiltration flow assigned by eQUEST<br>
to each perimeter space is not depended on the climate.<br>
<br>
<br>
<br>
See the help section screenshot below:<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
It is a flat rate assigned to each space and does not include any<br>
wind speed correction and inside-outside temperature difference. The 0.038<br>
cfm/ft2 (of external wall area) infiltration rate was included in the ASHRAE<br>
Standard 90.1-1989 as a beginning assumption and that's what shows up in<br>
eQUEST as default.<br>
<br>
<br>
<br>
It is good that you are questioning the effect of infiltration on the<br>
energy use of building that you are modeling. In the absence of blower door<br>
test results it is difficult to imagine the real infiltration rate in a<br>
building as it depends on many factors such as the workmanship of the actual<br>
construction, stack effect, inside-outside temperature difference, wind-speed<br>
and how well the building is pressurized by the HVAC system.<br>
<br>
<br>
<br>
I'll suggest go through the following study by PNNL: Infiltration<br>
Modeling Guidelines for Commercial Building Energy Analysis<br>
<<a href="http://www.pnl.gov/main/publications/external/technical_reports/PNNL-18898.pdf" target="_blank">http://www.pnl.gov/main/publications/external/technical_reports/PNNL-18898.p<br>
df</a>><br>
<br>
<br>
<br>
Although the report is Energy Plus specific but it can be applied to<br>
eQUEST as well. In a recent project I used the PNNL guidelines and further<br>
converted the infiltration flow for each space to air-changes per hour to<br>
take the wind-speed correction into account. This method still has limitation<br>
of not taking into account the inside-outside temperature difference (see<br>
above screen-shot). I found the rest of the methods that include both<br>
wind-speed correction and inside-outside temperature difference to be<br>
specific to residential buildings.<br>
<br>
<br>
<br>
Hope it helps.<br>
<br>
<br>
<br>
Thanks.<br>
<br>
<br>
<br>
Best regards,<br>
<br>
<br>
<br>
Gaurav<br>
<br>
<br>
<br>
Gaurav Mehta, LEED® AP BD+C<br>
Sustainable Building Analyst<br>
Stantec<br>
<br>
1932 First Avenue Suite 307<br>
Seattle WA 98101<br>
Ph: <a href="tel:%28206%29%20770-7779" target="_blank" value="+12067707779">(206) 770-7779</a> <tel:%28206%29%20770-7779><br>
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From: <a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a><br>
[mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] On Behalf Of Genest, Frederic<br>
Sent: Monday, August 01, 2011 6:03 PM<br>
To: ROBERT GOMEZ; <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
Subject: [Bldg-sim] RE : Infiltration effect in Climate 1<br>
<br>
<br>
<br>
<br>
<br>
Hello Richard.<br>
<br>
I'm not used to eQuest, but since it is using DOE in the background,<br>
same as EE4 I'm using more frequently, I'll try to answer correctly.<br>
<br>
Climate Zone has nothing to do with infiltration rates, except when<br>
in comes to wind speed and such. However, I don't think DOE is considering<br>
wind speed when calculating infiltration rates; it is usually defined as a<br>
constant, based on a value such as ACH or cfm/ft.sq. of wall area.<br>
<br>
As such, I would start to check your infiltration inputs to see what<br>
is defined, first in eQuest and then in the DOE input file. I'm pretty sure<br>
you'll find your answer somewhere there.<br>
<br>
Also note that design infiltration rate and "actual, under operating<br>
conditions" infiltration rate, are two different things. The average constant<br>
infiltration rate is adequate enough for the later one.<br>
<br>
Also, if you ever need to model a real infiltration from blower door<br>
test results, I personnaly use the 50 Pa value divided by 20 for actual,<br>
normal operation conditions, while the 75 Pa value would be divided by 35 (in<br>
whatever units those values are provided).<br>
<br>
Regards.<br>
<br>
<br>
<br>
Frederic Genest, ing., M.Sc.A.<br>
LEED AP, ASHRAE HBDP<br>
<a href="mailto:fgenest@pageaumorel.com" target="_blank">fgenest@pageaumorel.com</a><br>
<br>
Pageau Morel et associés<br>
210 Cremazie Ouest, suite 110<br>
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-------- Message d'origine--------<br>
De: ROBERT GOMEZ [mailto:<a href="mailto:rsg4999@yahoo.com" target="_blank">rsg4999@yahoo.com</a>]<br>
Date: dim. 31/07/2011 23:05<br>
À: <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br>
Objet : [Bldg-sim] Infiltration effect in Climate 1<br>
<br>
Hello all,<br>
<br>
I'm currently involved in a project that is located in International<br>
Climate Zone 1 (Very Hot - Humid). The building has no heating system, HVAC<br>
systems are only for cooling. Infiltration effect is smaller than I expected<br>
from the eQuest energy model result. I know it has something to do with the<br>
climate. Can anyone tell me the reason why?<br>
<br>
Thanks in advance!<br>
<br>
<br>
Richard Gulli<br>
Project Engineer<br>
<br>
<br>
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