[Sbse] ASHRAE Lowdown Showdown Modeling Competition

Paul Raftery p.raftery at berkeley.edu
Mon May 10 13:32:02 PDT 2021


... and of course our department server happens to be down when I posted
that, so that link is also temporarily down, which a few folks have kindly
let me know. The server should be back up soon, but until it is you can
access the tool directly here:
https://urldefense.com/v3/__https://centerforthebuiltenvironment.github.io/fan-tool/__;!!JYXjzlvb!3tLiw-zltXT419TEmPLZxKM5k2BIdNznv7F6o9wI0BOXc2fyHvRxjDApm3wdHA$ 

Thanks,

Regards,
Paul

On Mon, May 10, 2021 at 10:51 AM Paul Raftery <p.raftery at berkeley.edu>
wrote:

> It's great to see folks discussing including ceiling fans and air movement
> into their low-energy designs. Aside from expanding the range of
> comfortable temperatures and giving occupants more control, they also work
> particularly well with natural ventilation designs because they will
> substantially increase 'natural' ventilation on days with little
> wind-driven flow (e.g. an open exterior door, or center-pivot roof windows,
> etc. with a ceiling fan running)
>
> In case it's useful, we wrote a guide for designing with ceiling fans
> which is publicly available for free here
> <https://urldefense.com/v3/__https://escholarship.org/uc/item/6s44510d__;!!JYXjzlvb!3tLiw-zltXT419TEmPLZxKM5k2BIdNznv7F6o9wI0BOXc2fyHvRxjDBSu3hSiw$ >. Similarly, we built an
> in-browser web tool to help folks do some quick design sizing/selection for
> ceiling fans in spaces, available here: cbe.berkeley.edu/fan-tool.
>
> Let me know if you have any feedback, thanks!
>
> Regards,
> Paul
>
> Paul Raftery, Ph.D.
> Professional Researcher
> Center for the Built Environment <https://urldefense.com/v3/__http://www.cbe.berkeley.edu/__;!!JYXjzlvb!3tLiw-zltXT419TEmPLZxKM5k2BIdNznv7F6o9wI0BOXc2fyHvRxjDDiR6_6Uw$ >  |  University
> of California Berkeley <https://urldefense.com/v3/__http://berkeley.edu/index.html__;!!JYXjzlvb!3tLiw-zltXT419TEmPLZxKM5k2BIdNznv7F6o9wI0BOXc2fyHvRxjDALAr8nSA$ >
> Phone: + 1 (510) 725-0562
>
>
> On Mon, May 10, 2021 at 7:50 AM Nathaniel Jones <nathanieljon at gmail.com>
> wrote:
>
>> Hi Sue and Matthias,
>>
>> Of course ASHRAE has a method for calculating the pressure loss/speed
>> reduction through screens and grills. It's in the ASHRAE Handbook of
>> Fundamentals (in my 2009 edition it's chapter 21, tables CD6-1 and CR6-1).
>> The chapter is on duct design, but since this is just physics we're talking
>> about, it is applicable to other settings as well.
>>
>> As for pressure distributions around buildings, ASCE has methods that can
>> be applied to fairly normative building geometries for wind loading
>> calculations. However, more complex geometries and surrounding structures
>> result in unique wind pressure distributions that can only be analyzed with
>> wind tunnel or CFD tests (although there are some promising results from
>> reduced order models, i.e. machine learning). Matthias, if you are
>> interested in adding buoyancy (i.e. convection) to outside pressure
>> calculations, then I assume you are concerned with exhaust plume
>> re-entrainment, as this is the only case I can think of where the
>> temperature difference might be enough to counteract the force of wind. In
>> that case, CFD is really the only option. Given the possible harm to
>> occupants when exhaust is re-entrained into building air supply, I would be
>> hesitant to use a simplified or generic model in such a case.
>>
>> Nathaniel
>>
>> On Mon, May 10, 2021 at 7:04 AM Matthias Haase <mathaase at gmail.com>
>> wrote:
>>
>>> Dear all,
>>>
>>> I agree that we need guidelines for pressure drops of screens and other
>>> devices (e.g.  shading). But we also need more research on pressure
>>> distribution around buildings and within districts. These have to be
>>> measured and calculated taking local solar radiation, absorption and
>>> convection into account. Many models I have seen are not detailed enough
>>> and often make simplifying assumptions. Measurements of airflow around
>>> buildings is often very generic and static. Any hint to work that has
>>> focused on this is much appreciated! UHI is going in the right direction
>>> but often asks for UHI mitigation instead of designing with pressure
>>> differences. Again, hints to promising work in this direction are most
>>> welcome.
>>>
>>> best regards
>>>
>>> Matthias Haase
>>> Professor for Building systems at Institute for Facility Management -
>>> ZHAW Zurich University of Applied Sciences
>>> Editor of the International Journal of Sustainable Built Environment
>>> IJSBE
>>> Editor of the Journal of Green Building
>>>
>>> Guest Editor of  Energies (available in Web of Science - Special Issue on
>>>
>>> "Energy Efficiency Improvement Measures in Buildings
>>> <https://urldefense.com/v3/__https://www.mdpi.com/journal/energies/special_issues/energy_efficiency_improvement_measures_buildings__;!!JYXjzlvb!zwoS2CQR6mCWqocWcBXaZnWZ1p6qIvo0XeQc2fsefZ69acOpdownbhI_cmQgdg$>
>>> "
>>>
>>> and
>>>
>>>  “Sustainable Renovation and Energy Retrofit in Buildings
>>> <https://urldefense.com/v3/__https://www.mdpi.com/journal/energies/special_issues/building_renovation_energy_retrofit__;!!JYXjzlvb!zwoS2CQR6mCWqocWcBXaZnWZ1p6qIvo0XeQc2fsefZ69acOpdownbhKC9beiDw$>
>>>>>>
>>> Guest Editor of Frontiers Special Issue on Positive Energy Districts
>>> <https://urldefense.com/v3/__https://www.frontiersin.org/research-topics/14941__;!!JYXjzlvb!zwoS2CQR6mCWqocWcBXaZnWZ1p6qIvo0XeQc2fsefZ69acOpdownbhLZkfoLQg$>
>>> blogger
>>> <https://urldefense.com/v3/__https://blogg.sintef.no/author/matthiashaase/__;!!JYXjzlvb!zwoS2CQR6mCWqocWcBXaZnWZ1p6qIvo0XeQc2fsefZ69acOpdownbhLY5qIwYQ$>
>>> IBPSA, supporting member and project committee chair
>>> IBPSA, director-at-large
>>> IBPSA-nordic, president
>>> IBPSA-nordic, founding member
>>>
>>> Google Scholars
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>>>
>>> [image: supporting member 2019 logo - use restricted to supporting
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>>>
>>> <https://urldefense.com/v3/__https://scholar.google.no/citations?hl=en&user=mShniYkAAAAJ__;!!JYXjzlvb!zwoS2CQR6mCWqocWcBXaZnWZ1p6qIvo0XeQc2fsefZ69acOpdownbhLh44Kp8w$>
>>>
>>> "*We build too many walls and not enough bridges*"
>>>
>>> Sir Isaak Newton
>>>
>>>
>>>
>>> On Sun, May 9, 2021 at 11:28 PM Alexandra Rempel <arempel at uoregon.edu>
>>> wrote:
>>>
>>>> Hi Sue,
>>>>
>>>> It’s great to hear your thoughts on this! I sure hope you’re right that
>>>> natural ventilation will be a prominent strategy here, supplemented by
>>>> ceiling fans, of course! Passive heating and cooling have not been as
>>>> popular in the past few years as one might hope, but they’re gaining
>>>> ground.
>>>>
>>>>
>>>>
>>>> And no, I’m not aware of any ASHRAE strategy for calculating air speed
>>>> reductions for screens and grills. We definitely need something like that!
>>>>
>>>>
>>>>
>>>> Intriguingly, the teams are required to choose and defend their own
>>>> indoor air temperature setpoints; in the past, the adaptive comfort zone
>>>> has been used sporadically, and the air speed expansion to both standard
>>>> and adaptive comfort zones has not been fully exploited. I’m hoping this
>>>> program is an irresistible invitation to do that this year, though!
>>>>
>>>>
>>>>
>>>> I would love copies of all of the papers you mention; thank you so
>>>> much. I’ll look at the HVLS website, as well.
>>>>
>>>>
>>>>
>>>> Have you thought about coaching a team for this? There’s plenty of time!
>>>>
>>>> Take care, and thank you again so much for your input!
>>>>
>>>> Alex
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ---
>>>>
>>>> *Alexandra Rempel*, Ph.D., M.Arch.
>>>>
>>>> Assistant Professor of Environmental Design
>>>>
>>>> Environmental Studies Program
>>>>
>>>> University of Oregon, Eugene OR  97403
>>>>
>>>>
>>>>
>>>> *From:* Susan Roaf <s.roaf at btinternet.com>
>>>> *Sent:* Saturday, May 8, 2021 5:33 AM
>>>> *To:* Alexandra Rempel <arempel at uoregon.edu>; sbse at uidaho.edu
>>>> *Subject:* Re: [Sbse] ASHRAE Lowdown Showdown Modeling Competition
>>>>
>>>>
>>>>
>>>> Dear All,
>>>>
>>>>
>>>>
>>>> In that lovely climate there will be many who will want to run their
>>>> building complexes for as much of the day and year as possible using
>>>> natural ventilation which is the main way to reduce heating and cooling and
>>>> ventilation costs in buildings (that is obviously a no-brainer).
>>>>
>>>>
>>>>
>>>> Question - Does ASHRAE have a standard methodology for calculating
>>>> reductions in air movement due to insect screens and security grills?
>>>>
>>>>
>>>>
>>>> Ceiling fans will also be key to genuinely low energy buildings.
>>>>
>>>>
>>>>
>>>> This begs the question of what temperatures are inbuilt into the models
>>>> use for acceptable temperatures for fan and natural ventilation use.
>>>>
>>>>
>>>>
>>>> Fergus Nicol and I did a paper last November for the Dutch HVAC journal
>>>> for acceptable temperature ranges for naturally ventilated building - I
>>>> would be happy to send a copy to anyone interested.
>>>>
>>>>
>>>>
>>>> I also have a great paper by Dick Aynsley on calculating fan power etc
>>>> he did for a book I edited - I can send that too if you are interested. He
>>>> was an early expert for Big Ass Fans who also have a great resource site on
>>>> fan design: HVLS Design Guide (bigassfans.com)
>>>> <https://urldefense.com/v3/__https:/guide.bigassfans.com/__;!!C5qS4YX3!V41rAjKP6Hk9Rq1ESdqV4dV1e9n8wW_XSG8e9PrhE-JSCmsyeAeSunkm3yED2mIrFw$>
>>>>
>>>>
>>>>
>>>> In that climate a great idea is to use simple roof space extract fans
>>>> to pull air through the building from cooler / garden type places - where
>>>> planting and water etc can lower temps by up to 5C - from a shiny hot sunny
>>>> equivalent space with hard reflective surfaces - if not more.
>>>>
>>>>
>>>>
>>>> I have no doubt that such issues will dominate the submissions - or is
>>>> this for high energy buildings that need energy 24/7/365 - that cant be....
>>>>
>>>>
>>>>
>>>> Good luck with the interesting project.
>>>>
>>>>
>>>>
>>>> Best wishes
>>>>
>>>>
>>>>
>>>> Sue
>>>>
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