[Equest-users] Purpose of a DESIGN-DAY CLIMATE input?
Joe Huang via Equest-users
equest-users at lists.onebuilding.org
Fri Dec 2 14:23:47 PST 2016
Nick, others,
Your reading of the HOF is correct. As a member of TC 4.2 (Climatic Information), I
remember quite well the progression of events that led to the development of the new
ASHRAE Clear Sky Model. More than 10 years ago, the TC conducted an exercise to look
through the HOF to find where weather-related issues were being dealt with by other TCs.
This led to the design day formulation in the Loads Calculation section of the HOF and the
realization that the so-called ASHRAE Clear Sky Model was very antiquated, of unknown
provenance, and very North America - specific.
Since we had a very good solar expert in the TC (Chris Gueymard), we eventually contracted
with Chris to work with Didier Thevenard, the contractor for the ASHRAE Design Condition
tables, to create a better Clear Sky Model based on Chris' REST2 model. The REST2 Model
is a physical model that requires some 30 input parameters that can get very arcane
(Aerosol Optical Depth, Precipitable Moisture, etc.) but is very accurate (Chris once
said that NREL has found that REST2 was within 5% of NREL's measurements, which Chris
attributed to measurement errors :-) ).
Anyway, Chris compiled the inputs from satellite data and ran REST2 for the whole world,
which Didier then simplified into a 2-parameter model with a Taub and Taud for each
location and month, 24 numbers in all. So now the new ASHRAE Design Day procedure is to
look up the Taub/Taud for your location, plug those into two exponential equation, and get
the hourly profiles for GHI (global horizontal) and DNI (direct normal) by month (although
you still need to calculate the sun position in order to get the extraterrestrial
radiation, so don't try to do this in a spreadsheet just yet).
However, implementing it into DOE-2.2 would be very easy, since DOE-2 already calculates
the sun position. I just don't know whether anyone has tried to do so.
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 12/2/2016 11:18 AM, Nicholas Caton wrote:
>
> I think the “transition from doe2.1e” document may be congruous actually with Joe’s
> original suggestion… It does reinforce that we’re on the right track to consider CLIMATE
> as associated with determing solar pathing for design days.
>
> I’ve gone digging into Fundamentals 2005 and, googling after citations therein to try
> and lock in on this “Climate/Latitude” binning for solar angles. Found nothing direct
> in the Handbook to clarify but it does appear this (older) “ASHRAE clear sky model” was
> in fact limited to the Northern hemisphere (which may lead to why there’s seemingly
> nothing presently in DESIGN-DAY inputs to directly inform North vs South hemispheres… it
> seems a distinct possibility eQUEST makes a separate check of weather file latitude or
> other solar inputs however to account for this).
>
> I’ve come across many papers/names associated with evaluation and improvement of that
> clear sky model. The “midlatitude” term particularly pops up in a few such abstracts /
> summaries for papers I can’t readily access, so I suspect doe2.2 initially was following
> one such extension to the pre-2006 ASHRAE clear sky model.
>
> ~Nick
>
> *Nick Caton, P.E., BEMP*
>
> Senior Energy Engineer
> Energy and Sustainability Services
> Schneider Electric
>
>
>
> D 913.564.6361
> M 785.410.3317
> E nicholas.caton at schneider-electric.com <mailto:nicholas.caton at schneider-electric.com>
> F 913.564.6380
>
>
>
> 15200 Santa Fe Trail Drive
> Suite 204
> Lenexa, KS 66219
> United States
>
> cid:image001.png at 01D189AB.58634A10
>
> *From:*Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of
> *zhaoyongqing1987 via Equest-users
> *Sent:* Tuesday, November 29, 2016 7:54 PM
> *To:* Daric Adair via Equest-users <equest-users at lists.onebuilding.org>
> *Subject:* Re: [Equest-users] Purpose of a DESIGN-DAY CLIMATE input?
>
> DOE2.2 help files indicates that CLEARNESS and CLOUD-TYPE are now replaced by
> CLIMATE and VISIBILIY. It seems that CLIMATE is used for determine the clearness of sky.
>
> Volume 3: Topics <mailmaster://webui/pages/write/writemail_content.html> > Overview and
> Converting From 2.1E <mailmaster://webui/pages/write/writemail_content.html> > LOADS
> <mailmaster://webui/pages/write/writemail_content.html>
>
> DOE-2.1E version:
>
> HOT-CLEAR-SUMMER = DESIGN-DAY
> DRYBULB-HI = 91 DRYBULB-LO = 71
> HOUR-HI = 15 HOUR-LO = 7
> DEWPT-HI = 65.5 DEWPT-LO = 60
> DHOUR-HI = 16 DHOUR-LO = 8
> WIND-SPEED = 7.5 WIND-DIR = 10
> CLOUD-AMOUNT = 0 CLOUD-TYPE = 0
> CLEARNESS = 1 GROUND-T = 61 ..
>
> COLD-CLOUDY-WINTER = DESIGN-DAY
> DRYBULB-HI = 6 DRYBULB-LO = -4
> HOUR-HI = 15 HOUR-LO = 2
> DEWPT-HI = 6 DEWPT-LO = -4
> DHOUR-HI = 16 DHOUR-LO = 3
> WIND-SPEED = 15 WIND-DIR = 14
> CLOUD-AMOUNT = 5 CLOUD-TYPE = 2
> CLEARNESS = 1 GROUND-T = 46 ..
>
> Converted:
>
> "Chicago CDD" = DESIGN-DAY
> TYPE = COOLING
> DRYBULB-HIGH = 91 DRYBULB-RANGE = 20
> HOUR-HIGH = 15 HOUR-LOW = 7
> WETBULB-AT-HIGH = 77
> WIND-SPEED = 7.5 WIND-DIR = SW
> CLOUD-AMOUNT = 0 CLIMATE = MIDLATITUDE
> VISIBILITY = HIGH GROUND-T = 61
> ..
>
> "Chicago HDD" = DESIGN-DAY
> TYPE = HEATING
> DRYBULB-HIGH = 6 DRYBULB-RANGE = 10
> HOUR-HIGH = 15 HOUR-LOW = 2
> WIND-SPEED = 15 WIND-DIR = NW
> CLOUD-AMOUNT = 5 CLIMATE = MIDLATITUDE
> VISIBILITY = LOW GROUND-T = 46
>
> On 11/30/2016 07:04， David Griffin II via Equest-users
> <equest-users at lists.onebuilding.org <mailto:equest-users at lists.onebuilding.org>> wrote：
>
> Nick/Joe,
>
> I have done some light research on the topic since DOE2.3 moves in the direction of
> utilizing DESIGN-DAY more rigorously; e.g. if you depend on the weather file for
> auto sizing in DOE2.3, your simulation takes twice as long. I would refer both of
> you to page 23 of the DOE2.3 Volume 6 “Design-Sizing Enhancements” where it appears
> the eQUEST team is attempting exactly what Joe previously mentioned.
>
> Although I believe the CLIMATE input is still available in DOE2.3 it may be ignored
> by the new algorithm. Maybe Jeff H. can shed some light on this situation for us.
>
> Sincerely,
>
> ARCH | NEXUS <http://www.archnexus.com>
>
>
>
>
>
> DAVID W. GRIFFIN II
>
> BEMP
> ENERGY ANALYST
>
> 2505 E Parleys Way
> Salt Lake City, UT 84109
>
> *Office* 801.924.5028
>
>
>
> archnexus.com <http://www.archnexus.com>
>
> Twitter <https://twitter.com/arch_nexus>Facebook
> <https://www.facebook.com/pages/Architectural-Nexus/179588705397563?ref=ts&fref=ts>Youtube
> <https://www.youtube.com/channel/UCYRPWKF-yp-AUiI8ia2XfKw?feature=mhee>LinkedIn
> <https://www.linkedin.com/company/architectural-nexus>
>
> *From:*Joe Huang via Equest-users [mailto:equest-users at lists.onebuilding.org
> <mailto:equest-users at lists.onebuilding.org>]
> *Sent:* Tuesday, November 29, 2016 1:49 PM
> *To:* equest-users at lists.onebuilding.org <mailto:equest-users at lists.onebuilding.org>
> *Subject:* Re: [Equest-users] Purpose of a DESIGN-DAY CLIMATE input?
>
> I think this is a case of DOE-2 still using an older procedure for the solar portion
> of the design day calculation. Prior to 2006, ASHRAE used a relatively crude ASHRAE
> Clear Sky Model to determine the hourly profile of solar radiation for the design
> day. That model assumes there are different sky conditions for different latitudes,
> etc. In 2006, ASHRAE TC 4.2 (Climatic Information) carried out a project to develop
> an entirely new ASHRAE Clear Sky Model that's a parameterization of a detailed solar
> model developed by Chris Gueymard.
>
> It would be nice if DOE-2 incorporates the new ASHRAE Clear Sky Model, which isn't
> terribly hard, but would take work. Besides, I'm under the impression that the vast
> majority of DOE-2 users don't do design day calculations but rather let the program
> autosize the equipment anyway!
>
> Joe
>
> Joe Huang
>
> White Box Technologies, Inc.
>
> 346 Rheem Blvd., Suite 205A
>
> Moraga CA 94556
>
> yjhuang at whiteboxtechnologies.com <mailto: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 11/29/2016 9:43 AM, Nicholas Caton via Equest-users wrote:
>
> I have a question concerning doe2/eQUEST DESIGN-DAYs.
>
> One of the keywords for DESIGN-DAY confuses me: CLIMATE. I have not been able
> to find this documented in the current doe2 reference manual or 2.1A engineering
> manuals.
>
> It appears the CLIMATE keyword can accept one of three inputs: “SUBARCTIC,”
> “MIDLATITUDE,” or “TROPICAL.” The default is MIDLATITUDE and does not appear to
> reference anything else.
>
> So I have a few questions:
>
> 1.What is this input used for? Does it help to determine solar angles during
> design day calculations? Does it affect how other DESIGN-DAY inputs are
> interpreted?
>
> 2.Since one of the options is named “MIDLATITUDE,” my best guess is this is
> trying to establish in a loose sense which slice of the globe the weather
> station is located at for solar angle purposes. From that guess, I googled the
> topic for a bit <http://www.lat34north.com/cities/CitiesLatitude.cfm> and came
> up with this framework:
>
> a.SUBARCTIC latitudes are > 66.5 or < -66.5 (Inside the Arctic circles –
> experiences days of complete daylight/darkness)
>
> b.TROPICAL is between -23.5 and 23.5 (Tropic of Capricorn/Cancer – experiences
> the sun traversing directly overhead)
>
> c.MIDLATITUDE = everywhere else
>
> 3.I struggle however with the concept of a DESIGN-DAY input based on latitude, where
>
> a.The latitude is already a part of the weather file required for every
> simulation… and pulling the exact latitude would be more accurate anyway (I
> confess here I have never studied solar pathing in great depth – the problem may
> be simpler than I realize?).
>
> b.These bands alone don’t give you enough information to know when you’re in the
> lower hemisphere (where solar angles based on the day/month would be flipped)
>
> c.This leads me to question whether there’s a (meaningful) difference in solar
> angles experienced for loads calculations when you use the weather file instead
> of DESIGN-DAY inputs.
>
> d.Alternatively, maybe the latitude IS pulled from the weather file for solar
> angle purposes so I’m completely on the wrong path as to the purpose/intent for
> the CLIMATE input.
>
> Can anyone set me straight on this topic?
>
> ~Nick
>
> *Nick Caton, P.E., BEMP*
>
> Senior Energy Engineer
> Energy and Sustainability Services
> Schneider Electric
>
>
>
> D 913.564.6361
> M 785.410.3317
> E nicholas.caton at schneider-electric.com
> <mailto:nicholas.caton at schneider-electric.com>
> F 913.564.6380
>
>
>
> 15200 Santa Fe Trail Drive
> Suite 204
> Lenexa, KS 66219
> United States
>
> cid:image001.png at 01D189AB.58634A10
>
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