[Radiance-general] Daylighting metric for outdoor spaces

Thu Dec 1 20:34:43 PST 2011

Hi Michael,

Thank you for both emails today. I knew that statement is flawed, and I
think I mentioned that before. Nevertheless thank you for the links.

I think the best way, to find the answer, is to run series of annual
simulations for different locations. Will do soon.

Mostapha

On Thu, Dec 1, 2011 at 10:19 PM, Michael Donn <Michael.Donn at vuw.ac.nz>wrote:

> Hi Mostapha
>
> I asked my colleague Christina MacKay (Christina.MacKay at vuw.ac.nz) for
> references / inks to her papers defining 'warm shade', and received this
> list:
>
> Please refer to the following key papers -
>
> Mackay, C. (2009). Environmental Shade for Protection from UVR: A Design &
> Teaching Resource. Proceedings of the 26th Conference on Passive and Low
> Energy Architecture (PLEA). 22-24 June 2009. (pp 314-319). Quebec City,
> Canada.
> Mackay, C. (2006). Towards a safe sun-bathing canopy. The 23rd Conference
> on Passive and Low Energy Architecture. (pp. 581-586). Geneva, Switzerland.
> Mackay, C A. (2005, April). Living outside in the sun - a historical
> review of New Zealand outdoor living spaces. Inside-outside symposium,
> IDEA, RMIT. Melbourne, Australia.
> Gies, P., & Mackay, C A. (2004). Measurements of solar UVR protection
> provided by shade structures in New Zealand primary schools. Photochemistry
> and Photobiology, 80. (pp. 334-339). http:
> www3.interscience.wiley.com/cgi-bin/fulltext/11921593/htmlstart.
> Mackay, C A. (2003). Designing safe and comfortable indoor living spaces.
> Passive Low Energy Architecture, Proceedings of 20th International
> Conference, November 2003. Ins by Bustamante, W. & Collados, E. (Eds).
> Pontificia Universidad Catolica de Chile. B-24. (pp. 321-325). Santiago,
> Chile.
> Mackay, C A. (2003). Sunshade Design in New Zealand Primary Schools.
> Passive Low Energy Architecture - Proceedings of 20th International
> Conference, November 2003. Ins by Bustamante, W. & Collados, E. (Eds).
> Pontificia Universidad Catolica de Chile. A-18. (pp. 143-150). Santiago,
> Chile.
>
> Cheers
> Christina
>
>
>
> ------------------------------------
> Victoria University of Wellington School of Architecture
> Michael Donn
> michael.donn at vuw.ac.nz
> PO Box 600
> 139 Vivian St
> Wellington
> New Zealand
> tel: +64 4 463 6221
> fax: +64 4 463 6204
> mobile: +64 21 611 280
> Skype ID:the_donn
> ------------------------------------
>
> -----Original Message-----
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> Today's Topics:
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>   1. Re: Daylighting metric for outdoor spaces (Mostapha Sadeghipour)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 30 Nov 2011 19:27:27 -0600
> From: Mostapha Sadeghipour <sadeghipour at gmail.com>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Subject: Re: [Radiance-general] Daylighting metric for outdoor spaces
> Message-ID:
>        <CAAd_PgQhKsZ03xVk9ET+vJ3QFzCFn1JWE4=1uK+hD4LC6hxYLQ at mail.gmail.com
> >
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Andy,
>
> Thank you for clarification and explanation. It was so informative.
>
> I agree that using hours of sunshine (sunlight hours) in this way totally
> make sense however in the code I mentioned it was a metric for building
> envelopes (e.g. two hours of sunlight hours in 21st December is needed for
> residential buildings).
>
> As you said the weakness of metrics like VSC or Daylight Factor
> (SC+ERC+IRC) is not being climate-based and orientation sensitive but maybe
> this is the best possible way for now.
>
> Thanks,
> Mostapha
>
>
> On Wed, Nov 30, 2011 at 12:18 PM, Andy McNeil <amcneil at lbl.gov> wrote:
>
> > Hi Mostapha,
> >
> > BRE has a metric - Vertical Skylight Component - for what you describe.
> >  It is intended as a planning tool to insure that housing blocks are not
> > located to close together.  It is also used in rights to light litigation
> > in the UK.  It's independent of climate though, it's mainly to ensure
> that
> > an appropriate percentage of daylight is made available at the window
> (i.e.
> > not too many tall buildings nearby).  I'm not saying it's a great metric,
> > but it's commonly used for what you want to do.
> >
> > VSC is commonly coupled with the hours of sunshine in a courtyard metric
> > you mentioned in an earlier email.  I just want to point out that this is
> > not a daylight metric but a planning tool to ensure that courtyards are
> not
> > more damp and dank than an open park in the same climate.  For example,
> if
> > you have a week of damp overcast weather both your open space and your
> > courtyard will be damp, but then when you have a day of sunshine your
> park
> > will dry up, but your courtyard may not if there isn't sufficient sun
> > penetration.  A courtyard that stays damp gets even worse in the next
> week
> > of wet weather.  The metric is intended to prevent mold, mildew and
> > perpetually damp courtyards.  So in reality this metric is more
> applicable
> > to climates like London and Seattle than Phoenix or Dubai.
> >
> > Andy
> >
> >
> >
> > On Nov 30, 2011, at 9:31 AM, Mostapha Sadeghipour wrote:
> >
> > Hi John, Michael, et al.
> >
> > Michael,
> >
> > Sorry if it wasn't clear enough. I think you get the concept. Yes! I
> > wonder if there is a number to determine the outdoor illuminance to
> provide
> > enough illuminance level inside. What you are saying is true and the
> > effective parameters are much more than only VLT and ceiling reflectance
> > but if I want to consider all of them I should modify the geometry and
> run
> > the lighting simulation.
> >
> > The way I did the ray-tracing in my mind was the simplest possible
> > backward ray-tracing. I started from the sensor inside, then traced only
> > one ray upward and bounced it from the ceiling to the glazing. So
> > illuminance level inside the space is equal to illuminance level outside
> > the glazing (on the envelope of the building that I can simulate)
> multiply
> > by VLT of the glazing multiply by the reflectance of the ceiling. In this
> > way I can make a target for the illuminance level on the envelopes rather
> > than indoor.
> >
> > The question could be more general though and thinking about the relation
> > between outdoor illuminance level and then the external envelopes.
> >
> > John,
> >
> > Thank you for the great link! This is exactly what I'm talking about. I
> > actually ran the accumulative annual study. That's true that cumulative
> > result shows you get less illuminace in more dense areas but what are the
> > cutting levels? Do we have the concept of over-daylit for outdoors?
> >
> > For example if I calculate the availability of useful daylight
> illuminance
> > based on 100 lux and 2500 lux for working hours and calculate the result
> > based on the percentage of hours a large portion of the well-daylit
> outdoor
> > spaces will be considered as over-daylit because they receive more than
> > 2500 lux, and then the more dark outdoor spaces located in Seattle or
> > London (hi Rob!) will be assumed as well-daylit since they will be in the
> > range. We already knew this is not true and the spaces next to an outdoor
> > space with 150 lux horizontal illuminance level cannot be well-daylit.
> >
> > Maybe we can say there should be no upper-limit for outdoor illuminace
> > level since we can always mitigate the light level by building envelope
> > design, but what is the lower limit then?
> >
> > Best,
> > Mostapha
> >
> > PS.1: I liked the concept of "warm shade" so much. So interesting to
> think
> > about.... Can you send me a link to the paper or any other resources?
> >
> >
> > On Wed, Nov 30, 2011 at 10:26 AM, John Mardaljevic <jm at dmu.ac.uk> wrote:
> >
> >> Hi Mostapha,
> >>
> >> > For an urban design study I wanted to avoid measuring light levels
> >> inside the buildings as far as possible.
> >>
> >> How about using cumulative values, say annual or maybe monthly?  You
> >> could also look at just the hours of occupancy.  Some examples here:
> >>
> >> http://www.iesd.dmu.ac.uk/~jm/doku.php?id=academic:urban-solar
> >>
> >> The image for London clearly shows the effect of tall buildings reducing
> >> the ground level cumulative illuminance (actually, irradiance in the
> legend
> >> but just x 100 to estimate klux-hrs / yr).
> >>
> >> Best
> >> John
> >>
> >> Reader in Daylight Modelling
> >> Institute of Energy and Sustainable Development
> >> De Montfort University, The Gateway, Leicester, LE1 9BH, UK
> >> Tel: +44 (0) 116 257 7972
> >>
> >> jm at dmu.ac.uk
> >> http://www.iesd.dmu.ac.uk/~jm
> >> http://dmu.academia.edu/JohnMardaljevic
> >>
> >>
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