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<DIV><FONT face=Arial size=2>I was just responding to Chris' seemingly innocuous
question on how to calculate the mean monthly outdoor temperature. How is
that related to your program or any other loads or energy calculation
method? I haven't seen your program, but from your description, it sounds
like a derivative of the ASHRAE TC47 bin method. When that first came out in the
mid-70s, weren't there complaints then, too, that it was too complicated,
compared to the previous degree-day method ? I guess it's all a matter of
your perspective. If I may generalize, a degree-day method reduces
everything to a single calculation, a bin method calculates a few score of
snapshot conditions, while an hourly simulation tracks the building hour-by-hour
for 8760 hours. Each has their limitations and applicability.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>But back to what I had said about calculating the
mean monthly outdoor temperature from hourly data, this has nothing to do with
any calculation or simulation method. If the data are available, it can be done
using a spreadsheet program in literally a few seconds, which is why I'm puzzled
by your response.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Joe Huang</FONT></DIV>
<DIV><FONT face=Arial size=2>White Box Technologies, Inc.</FONT></DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
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<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=billhclark@bar-x-soft.com
href="mailto:billhclark@bar-x-soft.com">billhclark@bar-x-soft.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=joe@drawbdl.com
href="mailto:joe@drawbdl.com">Joe Huang</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A
title=bldg-sim@lists.onebuilding.org
href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, November 28, 2008 6:46
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: [Bldg-sim] calculating the
mean monthly outdoor temp</DIV>
<DIV><BR></DIV><SPAN
style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Verdana">Where did you
people get the idea the method used only max and min temperatures? It
uses total annual heating and cooling bin hours and langleys. The DOE
developed the method using nomographs - it works for them, and I don't see why
it can't work equally as well now. I do not claim it is as accurate as
the full blown methods on the market that tabulate loads for every hour and
every day. (If you really want to get pedantic, that method is quite
inaccurate, considering the extreme variability in weather.) My method is a
very good approximation - it is quick enough that the program operates like a
spreadsheet, and gives instantaneous data for every change made in the
model. You see the results on the same screen, and so can see exactly
what the result of changing roof color (which is dramatic), adding double
paned windows (which is effective only on south and west facing windows),
changing outside wall color (which has a significant impact), and so
forth. What other program can claim that kind of immediate result?
You see the effect on annual load from every single building element, and can
tweak them individually to find out what works best ~ all this one one screen,
real time ~ no waiting for massive print outs with every
iteration.<BR><BR>Actually, there are just as many draw backs to the
"standard" and "accepted" methods that do hourly calculations ~ the weather is
so variable and undependable. All anybody can do is develop a method that
gives dependable results, and that's what my program does ~ as good as any
product out there. Moreover, my software is quite simple ~ which
actually makes it better because the user can actually understand what he's
doing, see the results, and work forward accordingly. <BR><BR>How useful
is a massive program that takes a Masters Degree for the operator to
understand and use, a week to input all the data acceptably ~ versus a program
that anybody can use in minutes, and obtain a result in an hour? How
many expert energy auditors are there who can do the number of energy audits
needed to make any significant impact on energy usage for the U.S.? The
only way to make progress in reducing building energy use is to have a program
like mine that gives decent results quickly and with zero experience
required. Having all the results appear instantly on the screen actualy
makes the program fun to operate, and quite insightful and educational.
<BR><BR>BC<BR><BR>
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webmail="1">
<DIV>-------- Original Message --------<BR>Subject: Re: [Bldg-sim]
calculating the mean monthly outdoor temp<BR>From: "Joe Huang"
<joe@drawbdl.com><BR>Date: Thu, November 27, 2008 10:07 pm<BR>To:
"Chris Yates" <Chris@zed-uk.com>, "Building
Simulation"<BR><bldg-sim@lists.onebuilding.org><BR><BR>The cited
method sounds like a carry-over from when stations reported only <BR>max/min
temperatures.<BR>If hourly data is available, why wouldn't you just
calculate the mean of all <BR>the temperatures ?<BR><BR>Joe Huang<BR>White
Box Technologies<BR><BR>----- Original Message ----- <BR>From: "Chris Yates"
<Chris@zed-uk.com><BR>To: "Building Simulation"
<bldg-sim@lists.onebuilding.org><BR>Sent: Thursday, November 27, 2008
1:58 PM<BR>Subject: [Bldg-sim] calculating the mean monthly outdoor
temp<BR><BR><BR>> For the purpose of acceptability limits, can anybody
cite any guidance on <BR>> calculating the mean monthly outdoor
temperature? I've read ASHRAE 55 and <BR>> it states: "mean monthly
outdoor temperature is the arithmetic average of <BR>> the mean daily
minimum and the mean daily maximum outdoor (dry bulb) <BR>> temperature
for the month in question."<BR>> Thanks<BR>>
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