[Bldg-sim] MRT Tool

Timothy Moore timothy.moore at iesve.com
Tue Apr 21 20:19:02 PDT 2009


Regarding asymmetrical thermal comfort and that involving transmitted
short-wave radiation, the following link will get you an excellent
(lengthy, detailed, and very helpful) paper on thermal comfort in
proximity to windows. It discusses the effects of glass surface
temperatures and transmission properties, along with possible options
for including a rating of thermal comfort performance on NFRC window
labeling.

 

Huizenga, C., H. Zhang, P. Mattelaer, T. Yu, E. Arens, and P. Lyons,
2006. Window Performance for Human Thermal Comfort
<http://www.cbe.berkeley.edu/research/pdf_files/SR_NFRC2006_FinalReport.
pdf> . Final Report to the National Fenestration Rating Council, Center
for the Built Environment, University of California, Berkeley, February.

 

You do not need an open window to have comfort issues associated with
transmitted short-wave radiation, nor does it have to be direct-beam
radiation-any window permitting occupants to receive a good dose of
transmitted diffuse and/or direct solar radiation is reason enough to
care about this effect. The paper at the CBE link above provides a very
useful means of estimating the contribution of both direct-beam and
diffuse solar radiation. The discussion of the impact of diffuse
radiation begins on page 44 and the discussion of direct radiation
starts on page 49.

 

CBE's Advanced Thermal Comfort Model
<http://www.cbe.berkeley.edu/research/briefs-thermmodel.htm>  

This tool can used to study the effectiveness of energy saving design
strategies, such as facade designs and advanced HVAC systems, in terms
of occupant comfort. 



In addition, the CBE has an Advanced Thermal Comfort model that they
will be happy to run for you as consultants to your project (and which
their industry partners also have direct access to) which takes into
account short-wave radiation striking a human subject, along with
numerous very detailed thermal comfort parameters. This tool was used
for several key sections of the paper linked above, so you can see
examples of the model and results there. Not only does this model
account for occupant attributes like body mass (along with the usual
comfort parameters), it actually models 16 different human body parts
and the constriction and dilation of blood vessels that accompanies
different thermo-physiological states. This model, which is not really
all that difficult to work with, has been used for CBE consulting to the
automotive industry and a in-house by handful of large A&E firms. If you
want to learn more, the following link takes you to the section of the
CBE web site describing this tool:

 

Cheers,

Timothy

 

 

 


Timothy Moore 
Senior Consultant
Special Projects 


Office: 415 983-0603
timothy.moore at iesve.com <mailto:timothy.moore at iesve.com> 
www.iesve.com <http://www.iesve.com/> 

**Design, Simulate + Innovate with the <Virtual Environment>**

Email Disclaimer <http://www.iesve.com/disclaimer.html> 

 

 

 

 

 

 

 

 

From: JRR [mailto:energy.wwind at cox.net] 
Sent: Tuesday, April 21, 2009 7:44 PM
To: Peter Simmonds
Cc: Vikram Sami; Timothy Moore; Karen Walkerman;
bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] MRT Tool

 

JRR wrote;

Good Point !!  Do you take the radiation temperature at the virtual
surface of the open window ??
NO.  It is the wrong answer, but now you need to know things like the RT
of an adjacent building,
background sky RT, luminosity...

Peter Simmonds wrote: 

Ah, another can of worms. MRT is probably the least understood and
certainly the least calculated of space thermodynamics. ASHRAE RP 1383
was specifically set up to calculate MRT for spaces, even having unusual
configurations. It should be ready in about 18 months or so? 

So Vikram, with reference to your analogy, how about this one?

Imagine a space that is naturally ventilated through an open window, at
this certain time of the day the occupant is in such a position that the
suns rays reach the occupant through the open window. What would the MRT
be in the space and how would this affect the occupants comfort.

 

Peter Simmonds. Ph.D.
Senior Associate, Advanced Technology Group

IBE Consulting Engineers
14130 Riverside Drive Suite 201
Sherman Oaks, CA 91423
p:   (818) 377-8220 ext. 246
f:    (818) 377-8230
m:  (818) 219-1284

This e-mail message, including any attachments, is for the sole use of
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sender by reply e-mail and destroy all copies of the original message

 

________________________________

From: Vikram Sami [mailto:VSami at lasarchitect.com] 
Sent: Tuesday, April 21, 2009 12:02 PM
To: Peter Simmonds; Timothy Moore; Karen Walkerman; 
bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] MRT Tool

 

It's an interesting conundrum that the times that MRT becomes a
significant player in the comfort calculation is when there is an uneven
radiant field (hot or cold window; fireplace; thermal mass wall). In
such a situation, is it fair to average out the MRT for an entire room?
Don't your view factors change drastically depending on your position in
the room? 

 

Does one person too hot near the window and another person too cold on
the inside equal thermal comfort?  

 

Vikram Sami, LEED AP 
Direct Phone 404-253-1466 | Direct Fax 404-253-1366 

LORD, AECK & SARGENT ARCHITECTURE
1201 Peachtree Street NE, Suite 300, Atlanta, GA 30361 
Responsive Design * Technological Expertise * Exceptional Service 
Please visit our new website | www.lordaecksargent.com
<file:///\\%5C%5Cwww.lordaecksargent.com%5C> 

P Think GREEN before you print.

 

 

From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Peter
Simmonds
Sent: Tuesday, April 21, 2009 1:36 PM
To: Timothy Moore; Karen Walkerman; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] MRT Tool

 

I do not think the thermal comfort tool calculates the MRT it is a user
input.

 

Peter Simmonds. Ph.D.
Senior Associate, Advanced Technology Group

IBE Consulting Engineers
14130 Riverside Drive Suite 201
Sherman Oaks, CA 91423
p:   (818) 377-8220 ext. 246
f:    (818) 377-8230
m:  (818) 219-1284

This e-mail message, including any attachments, is for the sole use of
the intended recipient(s) and may contain confidential and privileged
information. Any unauthorized review, use, disclosure, or distribution
is prohibited. If you are not the intended recipient, please contact the
sender by reply e-mail and destroy all copies of the original message

 

________________________________

From: Timothy Moore [mailto:timothy.moore at iesve.com] 
Sent: Tuesday, April 21, 2009 10:00 AM
To: Karen Walkerman; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] MRT Tool

 

Karen,

 

The ASHRAE-55 Thermal Comfort Tool created by the UC Berkeley Center for
the Built Environment and available from ASHRAE publications (if I
recall correctly) includes a very easy-to-use MRT calculator for
rectangular rooms. It allows for MRT at a particular position in that
room, separate surface temperatures and dimensions for surfaces, and
also the inclusion of a "panel" or other area within one of the walls
(such as a cold/hot window, heating panel, etc.) that has a distinct
temperature. This is part of a very handy tool for determining PPD, etc.
based upon the typical range of human thermal comfort variables (clo
value, activity level, air temp, MRT, humidity, air movement).

 

Cheers,

Timothy

 

 

 


Timothy Moore 
Senior Consultant
Special Projects 

Mobile: 415 810 2495 
Office: 415 983-0603
timothy.moore at iesve.com <mailto:timothy.moore at iesve.com> 
www.iesve.com <http://www.iesve.com/> 

**Design, Simulate + Innovate with the <Virtual Environment>**

Email Disclaimer <http://www.iesve.com/disclaimer.html> 

 

 

 

 

 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org [
mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Karen
Walkerman
Sent: Tuesday, April 21, 2009 9:50 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] MRT Tool

 

Hello,

Is anyone aware of a simple Mean Radiant Temperature calculation tool?
I'm looking for something that will calculate MRT for a basic
rectangular room.

Thanks!

--
Karen

 


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