[Bldg-sim] [ASHRAE-TC4.2] Re: cold war, cold weather...
Joe Huang
yjhuang at whiteboxtechnologies.com
Sat Jun 8 18:25:19 PDT 2019
I think my previous response was a tad short, so I'll elaborate :-) (What actually
happened was that I was composing my answer on my IPhone that sent it out unexpectedly,
so I decided to wait until I got to the office where I'm in more control of the e-mail).
Chris,
Yes, you're correct on both points. The percentiles are of all the hourly values in the
long-term record, so 0.4% would mean there are on average 35 hours at or above that
temperature over a year, and so forth. The pre-1996 definition of 1% seasonal would be 22
hours at or above that temperature over 2208 hours from June through August. If all the
hours above that temperature would occur only in those three summer months, the 1%
seasonal would correspond to 0.25% annual. However, there are almost always such hours
that occur outside of those months and since the frequency of occurrence varies greatly by
climate, it's impossible to find an universal correspondence of annual to seasonal
frequencies. For example, in Singapore where there is very little season variation in
temperatures, the 1% seasonal would be about the same as the 1% annual, or 88 hours over a
typical year, more than double the number of hours in a temperate climate. Because of
these inconsistencies and the awkwardness of having to define summer and winter in
different locations (here in San Francisco the hottest month is always September), ASHRAE
decided to change from seasonal to annual percentiles for the 1997 Handbook. I was on TC
4.2 at the time, and what transpired with this switch was interesting and at times
humorous. If we switch to annual percentiles, which percentiles should we use? Engineers
are very attuned to "their" design temperatures, so we didn't want to create an uproar
with large changes in the design temperatures due to changes in the metric, but new metric
does not produce a one-to-one correlation to the old metric. In the end, the TC asked the
contractor to compare the temperatures at different annual percentiles to the old seasonal
percentiles, and use the annual percentiles with the best overall match, which turned out
to be 0.4%, 1%, and 2% for the previous 1%, 2.5% and 5% seasonal percentiles.
There are many things in the ASHRAE design procedure that are similarly ad-hoc or
evolutionary, to use a better adjective :-) , which is why I tend to view it with a slight
grain of salt. I've also talked to engineers and academics in other countries over the
years, and have that the ASHRAE design procedure is only one of several in the world.
Joe
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"
On 6/8/2019 5:03 PM, Joe Huang wrote:
> The 1%, 99% used prior to
>
> Sent from my iPhone
> Joe Huang
> White Box Technologies
> 346 Rheem Blvd Suite 108D
> Moraga CA 94556
> (o) 1(925)388-0265
> (c) 1(510)928-2683
> yjhuang at whiteboxtechnologies.com <mailto:yjhuang at whiteboxtechnologies.com>
>
> On Jun 8, 2019, at 3:58 PM, Dru Crawley <dbcrawley at gmail.com
> <mailto:dbcrawley at gmail.com>> wrote:
>
>> 1 percent of 8760 = 87.6
>>
>> On Sat, Jun 8, 2019, 6:03 PM Chris Yates via Bldg-sim <bldg-sim at lists.onebuilding.org
>> <mailto:bldg-sim at lists.onebuilding.org>> wrote:
>>
>> Thanks Joe. This is fascinating.
>>
>> My understanding of the percentiles 0.4, 1.0, 99 & 99.6% design data was that they
>> covered everything except the coldest or hottest 35 or 87.6 hours in a typical
>> year. I need to double check my understanding. All I know is that it seems to work
>> the opposite way around if I use Excel's PERCENTILE.INC function!
>>
>> Was the translation of the 1% to 0.4% based on the former being two seasons?
>>
>> On 7 Jun 2019 21:20, "Michael J Witte via Bldg-sim" <bldg-sim at lists.onebuilding.org
>> <mailto:bldg-sim at lists.onebuilding.org>> wrote:
>>
>> Thanks Joe - I was hoping someone would chime in with more authority. And a
>> fascinating personal history - who knew?
>>
>> On 6/7/2019 2:36 PM, Joe Huang via Bldg-sim wrote:
>>> As the current chair of TC 4.2 Climatic Information, I feel obligated to reply
>>> :-)
>>>
>>> While I admire Chris' and your enthusiasm, I am pretty certain that the design
>>> temperatures in the ASHRAE Handbook grew out of the needs of the HVAC
>>> engineers going back at least to the 1940's for cooling, and even much earlier
>>> for heating. I'm hoping that Jeff Haberl can clarify the situation and have
>>> cc'd him on this e-mail to get his attention. I've also cc'd the TC4.2 Group
>>> in case others remember more clearly the history of ASHRAE design
>>> temperatures. If I were a betting man, I would wager the HOF design
>>> temperatures came out of either the industry (Carrier ?) or engineers within
>>> the predecessor societies AHVE, ASHE that merged in 1959 to form ASHRAE, and
>>> that the Air Force adopted it in their publication, rather than the other way
>>> around. As Michael had pointed out, the AF publication states that the design
>>> temperatures were "intended to support design and construction of DOD
>>> facilities", with no mention of use in military aviation.
>>>
>>> It's funny how this almost off-the-cuff decision had endured and got
>>> embellished to make it seem more hefty. For example, in the 1960's engineers
>>> got concerned about dynamic effects and so added on hourly profiles for
>>> temperature, solar, wind, etc., to create an artificial design day, and in the
>>> 1990's to accommodate climates with different seasons (or no seasons!) the
>>> criteria was switched from a seasonal 1% to an annual 0.4%. Why 0.4% ?
>>> Simply because the temperatures would match the previous 1% seasonal (I was
>>> in TC 4.2 at the time and recalled those discussions). The evolution of
>>> ASHRAE Design Conditions would seem also to make an interesting and
>>> informative paper.
>>>
>>> As far as meteorology having an impact on military operations, I can describe
>>> an old family story. My father, Dr. Hsia-Chien Huang
>>> <https://www.gettyimages.co.uk/photos/irving-p.-krick-dr.-hsia-chien-huang?sort=mostpopular&mediatype=photography&phrase=irving%20p.%20krick%20dr.%20hsia%20chien%20huang&license=rf,rm&page=1&recency=anydate&suppressfamilycorrection=true>,
>>> was the Chief Meteorologist of China during World War Two. He received his
>>> Ph.D. at Caltech in the late 1930's studying with Dr. Irving Krick
>>> <https://en.wikipedia.org/wiki/Irving_P._Krick>. Dr. Krick was hired by
>>> General Eisenhower to forecast the weather for the Normandy Invasion. The
>>> details are in the web page so I won't describe them here, only to say that I
>>> grew up hearing that Dr. Krick predicted the weather for the invasion and that
>>> someone in the UK actually produced a play about this incident. Since Dr.
>>> Krick sponsored my family to the US in 1955, I can say that the only reason
>>> I'm in the US is due to meteorology! For the oldtimers in TC 4.2, can you
>>> guess who picked up my family when we arrived in Denver 64 years ago? Loren
>>> Crow, who was then working for Dr. Krick, as did my father afterwards. Loren
>>> was very involved in TC 4.2 up until the early 1990s, having created the
>>> original WYEC files and the CTZ files for California. Gee, maybe all these
>>> deep personal connections to meteorology might explain my late life
>>> pre-occupation with weather data!
>>>
>>> Joe
>>>
>>> On 6/7/2019 7:05 AM, Michael J Witte via Bldg-sim wrote:
>>>> Chris - Sure, go right ahead and write a joint article for CIBSE and ASHRAE.
>>>>
>>>> I know ASHRAE is working on interviewing those with a long-time perspective
>>>> (old-timers) to document early ASHRAE work.
>>>> Jeff H - anything related to weather data happening in the history effort?
>>>> Maybe some members of the weather data TC would contribute.
>>>>
>>>> Linda - Does the forward of Engineering Weather Data have any mention of the
>>>> motivation for that data? Is that where the concept of using 99% etc. was
>>>> first used?
>>>>
>>>> Anyone out there have a copy of the Fluor Products publication? It was cited
>>>> as the source of the US design data in the 1972 HOF.
>>>> Evaluated Weather Data For Cooling Equipment Design, Addendum No. 1, Summer
>>>> and Winter Data (Fluor Products Company, Santa Rosa, Calif., 1964).
>>>>
>>>> On 6/6/2019 8:30 AM, Linda Lawrie wrote:
>>>>> I have a copy of the Engineering Weather Data document (1978 version).
>>>>> (Thanks, Bob H).
>>>>>
>>>>> And many other historical "weather data" documents though not sure how many
>>>>> discuss heating/cooling design data.
>>>>>
>>>>> Linda
>>>>>
>>>>> At 04:32 AM 6/6/2019, Chris Yates via Bldg-sim wrote:
>>>>>
>>>>>> Wow. You know what Michael. I think you have the makings of an ASHRAE
>>>>>> journal atricle! I want to do something similar for CIBSE. I'd love to use
>>>>>> your findings.
>>>>>> On 5 Jun 2019 23:21, "Michael J Witte via Bldg-sim"
>>>>>> <bldg-sim at lists.onebuilding.org <mailto:bldg-sim at lists.onebuilding.org>> wrote:
>>>>>>
>>>>>> I haven't seen a reply yet to this, so here goes . . .
>>>>>>
>>>>>> The oldest ASHRAE handbook on my shelf is a 1972 HOF (thanks Bob H.!).
>>>>>> Chapter 33 is Weather Data and Design Conditions. The reference list
>>>>>> includes these two primary sources:
>>>>>>
>>>>>> Evaluated Weather Data For Cooling Equipment Design, Addendum No. 1,
>>>>>> Summer and Winter Data (Fluor Products Company, Santa Rosa, Calif., 1964).
>>>>>> and
>>>>>> Engineering Weather Data (Army, Navy, and Air Force Manual TM 5-785, 1963).
>>>>>>
>>>>>> You can buy a copy of the 1958 edition of Evaluated Weather Data on amazon
>>>>>> https://www.amazon.com/Evaluated-Weather-Cooling-Equipment-Design/dp/B000HDSNFY
>>>>>>
>>>>>>
>>>>>> I bet someone out there has a copy of the Engineering Weather Data
>>>>>> manual on a shelf. Some quick searching leads to this later online version.
>>>>>> http://web.utk.edu/~archinfo/EcoDesign/escurriculum/weather_data/weather_data_summ.html
>>>>>>
>>>>>> which says:
>>>>>>
>>>>>> "The Engineering Weather Data (EWD) and other products were developed
>>>>>> by the Air Force Combat Climatology Center (AFCCC). Data is provided
>>>>>> for approximately 800 stations worldwide. Intended to support design
>>>>>> and construction of DOD facilities, the format is slanted toward
>>>>>> professional engineers, but could have numerous other uses. "
>>>>>>
>>>>>> Searching AFCCC leads here to a fascinating history.
>>>>>> https://www.airweaassn.org/Library/afwa/history.html
>>>>>> <https://www.airweaassn.org/Library/afwa/history.html>
>>>>>>
>>>>>> "The mission of AFCCC is one of military applied climatology. We
>>>>>> collect, maintain, and apply worldwide weather data, creating
>>>>>> climatological products to strengthen the combat capability of
>>>>>> America's warfighters. AFCCC's support to America's warfighters has a
>>>>>> long history."
>>>>>>
>>>>>> And a fitting excerpt on the 75th anniversary of D-Day:
>>>>>>
>>>>>> "There was probably no WWII operation, major or minor, that did not
>>>>>> include climatological input. The planning for every landing, mission,
>>>>>> and offensive, including the D-Day invasion in 1944 and the atomic
>>>>>> bombing of Japan, required extensive climatological preparation and
>>>>>> analyses."
>>>>>>
>>>>>> So, Chris, your impression appears correct. Weather data statistics
>>>>>> were motivated by military requirements (for better or worse), and
>>>>>> marketing cooling equipment.
>>>>>>
>>>>>> Mike
>>>>>>
>>>>>> p.s. The pages from the 1972 HOF are included in a digitized NBSLD
>>>>>> manual (one of the great mother programs of building simulation), pdf
>>>>>> p. 287ff.
>>>>>> https://www.govinfo.gov/content/pkg/GOVPUB-C13-9bcc6856169c63cf2c5ab81af189bd75/pdf/GOVPUB-C13-9bcc6856169c63cf2c5ab81af189bd75.pdf
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 5/20/2019 4:16 AM, Chris Yates via Bldg-sim wrote:
>>>>>>> Hi All
>>>>>>>
>>>>>>> Does anybody have any interesting background on the sources of
>>>>>>> (and motivations for calculating) the outdoor design conditions
>>>>>>> now available in ASHRAE HOF?
>>>>>>>
>>>>>>> My impression is that it was possibly derived for the purposes of
>>>>>>> keeping B52's and allied v-bombers ready for action at a moment's
>>>>>>> notice.
>>>>>>>
>>>>>>> Cheers
>>>>>>>
>>>>>>> Chris
>>>>>>>
>>>>>>>
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