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<p>I agree with you in principle, but have some differences in
implementation -)</p>
<p>I think it's a shame that typical year weather files* have become
regarded as the end-all for weather data, whereas they are just
meant as a snapshot. Running multiple years clearly has its
advantages, especially if you're concerned about performance under
extreme conditions, but realistically that would push up
significantly the computational effort, as well as that to digest
all that data :-).</p>
<p>What I find lacking in using a typical year file is that you get
the average performance, but not the error bands showing how much
that could vary year-to-year. Instead of running the entire time
series, I thought about selecting the years with the highest
heating and cooling consumption. Those years will vary depending
on the building (a glass box might have peak cooling in a year
with a lot of sunshine, while a building with no windows might
have a year with the most cooling degree days). About 4 years ago
I made a presentation at ASHRAE where I used a modified bin method
to calculate the load for a sample building and pick these peak
years.</p>
<p>Anyway, what I've been thinking is to provide not just the
typical year, but also the peak historical years for heating and
cooling. <br>
</p>
<p>Joe<br>
</p>
<p>* I do not like to use TMY as a generic label, since TMY refers
to a specific product and methodology developed by NREL<br>
</p>
<pre class="moz-signature" cols="90">Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
<a class="moz-txt-link-abbreviated" href="mailto:yjhuang@whiteboxtechnologies.com">yjhuang@whiteboxtechnologies.com</a>
<a class="moz-txt-link-freetext" href="http://weather.whiteboxtechnologies.com">http://weather.whiteboxtechnologies.com</a> for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
</pre>
<div class="moz-cite-prefix">On 12/24/2020 8:13 AM, Justin Spencer
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAB+zL_=y1jFgm1nkj8EkU05GfNmH13gJcQGXm-pPFV_jH=hj2g@mail.gmail.com">
<div>
<div dir="auto">My personal opinion is that while TMYs are nice,
given computing power available today and the new problems we
are going to need to solve, where the value of energy changes
by orders of magnitude and extreme conditions matter, we
should be considering running with many years of weather data
instead. I’ve had some projects where we did this, but my
business is all about grid impacts of aggregations of
buildings, which is a little different use case than most. My
sense is that you generally work with TMY and then move to
running the weather decades and perhaps then focusing on the
weather year with your design shortage condition, before
returning to the weather decades. Maybe we will still slice
2020 out, just because. </div>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">Happy holidays!</div>
<div><br>
<div class="gmail_quote">
<div dir="ltr">On Thu, Dec 24, 2020 at 6:46 AM Joe Huang via
Bldg-sim <<a href="mailto:bldg-sim@lists.onebuilding.org"
moz-do-not-send="true">bldg-sim@lists.onebuilding.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote">
<div>
<p>:-)</p>
<p>Presenting metadata or applying checksums would pick
out arithmetic or unit errors like what happened in the
original TMY3s, but better documentation of the data and
their provenance is the key to making sense of a weather
file. This thread has been talking about mistakes in
the TMY3s, but I give credit to NREL for developing the
TMY2/TMY3 format that added flags to every data element
and included the actual time stamp. <br>
</p>
</div>
<div>
<p>Joe<br>
</p>
<pre cols="90">Joe Huang
White Box Technologies, Inc.
<a href="https://www.google.com/maps/search/346+Rheem+Blvd.,+Suite+205A%0D%0AMoraga+CA+94556?entry=gmail&source=g" moz-do-not-send="true">346 Rheem Blvd., Suite 205A
Moraga CA 94556</a>
<a href="mailto:yjhuang@whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">yjhuang@whiteboxtechnologies.com</a>
<a href="http://weather.whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">http://weather.whiteboxtechnologies.com</a> for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
</pre>
<div>On 12/24/2020 3:28 AM, Chris Yates wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Like glazing, I'm often a bit lost when it comes
to rooting out the right weather file. In one
instance, this has even led to purchasing the same
data twice from CIBSE!</div>
<div><br>
</div>
I've thought that either better presentation of
metadata or applying checksums to weather files could
get around this.
<div><br>
</div>
<div>Chris</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Tue, Dec 22, 2020
at 1:11 AM Joe Huang via Bldg-sim <<a
href="mailto:bldg-sim@lists.onebuilding.org"
target="_blank" moz-do-not-send="true">bldg-sim@lists.onebuilding.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote">
<div>
<p>I forgot to mention as an aside I noticed that
NREL had taken the (revised) TMY3 files offline
several months ago. However, these TMY3s in EPW
and BINM formats are still available on my Web
site at <a
href="http://weather.whiteboxtechnologies.com/TMY3"
target="_blank" moz-do-not-send="true">weather.whiteboxtechnologies.com/TMY3</a>.
I'm also in the process of adding the *.CSV
format to the files now that they're gone from
the NREL Web site.</p>
<p>Joe<br>
</p>
<pre cols="90">Joe Huang
White Box Technologies, Inc.
<a href="https://www.google.com/maps/search/346+Rheem+Blvd.,+Suite+205A%0D%0AMoraga+CA+94556?entry=gmail&source=g" moz-do-not-send="true">346 Rheem Blvd., Suite 205A
Moraga CA 94556</a>
<a href="mailto:yjhuang@whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">yjhuang@whiteboxtechnologies.com</a>
<a href="http://weather.whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">http://weather.whiteboxtechnologies.com</a> for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
</pre>
<div>On 12/21/2020 3:55 PM, Joe Huang wrote:<br>
</div>
<blockquote type="cite">
<p>Interesting to see my work described by
someone who was never involved. The original
driver for doing that work was to correct the
decimal mistake in some of the illuminance
data that NREL had noted in 2005 but never
corrected because the original developers had
retired. The reporting of precipitation was an
additional improvement I offered to NREL, and
actually ended up the lion's share of the work
because it required reprocessing all the
source weather files. Neither of these
corrections/improvements should affect any
other weather set developed from scratch. i
have always been careful to not infringe on
NREL's branding of TMY for a number of
reasons, one of which has just been shown that
all TMYs are assumed to be related.<br>
</p>
<p>Joe<br>
</p>
<pre cols="90">Joe Huang
White Box Technologies, Inc.
<a href="https://www.google.com/maps/search/346+Rheem+Blvd.,+Suite+205A%0D%0AMoraga+CA+94556?entry=gmail&source=g" moz-do-not-send="true">346 Rheem Blvd., Suite 205A
Moraga CA 94556</a>
<a href="mailto:yjhuang@whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">yjhuang@whiteboxtechnologies.com</a>
<a href="http://weather.whiteboxtechnologies.com" target="_blank" moz-do-not-send="true">http://weather.whiteboxtechnologies.com</a> for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
</pre>
<div>On 12/21/2020 3:04 PM, Linda Lawrie via
Bldg-sim wrote:<br>
</div>
<blockquote type="cite"> the TMY3 files on <a
href="http://climate.onebuilding.org"
target="_blank" moz-do-not-send="true">climate.onebuilding.org</a>
have been corrected from the document posted
by Joe Huang on the tmy3 site. But I think
that was for precipitation.<br>
<br>
the TMYx files would never have had this
problem as they come from a different source
of our creation for the TMYx files.<br>
<br>
And, as I remember, the illuminance problem
was corrected by NREL at some point after
their first post.<br>
<br>
------<br>
Linda<br>
<br>
FIBPSA, FASHRAE<br>
<a href="http://climate.onebuilding.org/"
target="_blank" moz-do-not-send="true">
http://climate.onebuilding.org</a> - free
repository of climate data for building
simulation<br>
Climate.onebuilding is a FREE service not
supported by any outside organization or
government agency. <br>
<br>
<br>
<br>
<blockquote type="cite">Does anyone know if
the errors described in TMY3 files in this
post from Joe Huang on Jan 14 2015 still
exist in files on the <a
href="http://climate.onebuilding.org/"
target="_blank" moz-do-not-send="true">
http://climate.onebuilding.org/</a>
website? And were these errors also fixed in
TMYx files?<br>
<br>
Specifically I’m interested in this issue:<br>
<br>
<br>
1) Illuminance. The TMY3s contain values for
Global Horizontal, Direct Normal, Diffuse<br>
Horizontal, and Zenith Illuminance that are
calculated based on the sun position and
solar<br>
radiation. Although the documentation states
that the units are 100 lux for the first<br>
three illuminances, and 10 candela/m2 for
the Zenith Illuminance, all the TMY3 files
used<br>
these units only for the period Jan. 2-31,
and for the rest of the year used units of
lux<br>
and candela/m2, respectively. NREL put out a
notice in August 2008 (see the link listed<br>
earlier) informing users of this discrepancy
and promising a corrected version that
didn't<br>
make it out until now! In this revision,
we've decided to keep the units in the
original<br>
TMY3 documentation, i.e., 100 lux or 10
candela/m2, which is the same as what was in
the<br>
TMY2, and avoids the superfluous five-digit
precision.<br>
<br>
If I use a TMY3 or TMYx file from the <a
href="http://climate.onebuilding.org"
target="_blank" moz-do-not-send="true">climate.onebuilding.org</a>
website, am I getting a TMY3 or TMYx version
in which these issues are corrected?<br>
</blockquote>
<br>
<fieldset></fieldset>
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