[BLDG-SIM] atrium natural ventilation

[Guillaume Jolly]

Dear Nick 
I am currently working on a similar kind of project and I think that you are going to need to use CFD to determine accurately the amount of air that goes from one zone to the next above for a few different summer conditions and then feed that back in TAS. That's would be a simple and limited approach though.
Much better, in order to determine the overheating conditions accurately , i would run a transient CFD model over a whole day (I don't think that in the UK you would have overheating at night like here in Brisbane) , and increase the external heat loads applied to the Boundaries until you get overheating. Then I would compare this model with TAS and check when these kind of heat loads are happening over a whole year period. The hours that your heat loads are superior to the overheating conditions in your cfd model are your overheating hours. Simple in theory and if you have a good CFD software ...
It's really important in these case to run transient CFD problem since the airflow patterns determined by cfd have a huge impact on thermal comfort and transient phenomena (thermal storage ) have a huge impact on your airflow patterns...
All the best!
 

Best Regards

Guillaume Jolly

George Floth Pty. Limited

CONSULTING ENGINEERS BRISBANE OFFICE
Ground Floor, 42 Doggett Street
Fortitude Valley, Brisbane. 4006
p +61 7 3252 0977
f +61 7 3252 2499
e gjolly at gfbris.com <mailto:gjolly at gfbris.com> 

w www.gfbris.com <http://www.gfbris.com/> 

 

  _____  

From: postman at gard.com [mailto:postman at gard.com] 
Sent: 19 October 2007 18:01
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] BLDG-SIM at GARD.COM message digest 10/19/2007 03:01 (#2007-1044)


BLDG-SIM at GARD.COM message digest 10/19/2007 03:01 (#2007-1044)
 
11 messages included in this issue
  _____  


1	atrium natural ventilation	bldg-sim at ndoylend.fastmail.fm	
2	atrium natural ventilation	jeremy at esru.strath.ac.uk	
3	Green Building Jobs in Boston - All Levels	doug at greenroundtable.org	
4	TRNSYS Training	bradley at tess-inc.com	
5	GSHP System Pump Error	keith_lane at g-g-d.com	
6	Complex shading device in Ecotect	ruju_r at yahoo.com	
7	[Campus Chilled Water] eQUEST: Central Chiller for Baseline?	jevans at sustaineng.com	
8	Ecotect skylights	adamjackaway at yahoo.com	
9	eQuest - error CHW temp vs. LAT	astevens at dmiinc.com	
10	[Campus Chilled Water] eQUEST: Central Chiller for Baseline?	btalbert at aeieng.com	
11	Ecotect skylights	Michael.Donn at vuw.ac.nz	

  _____  



Date: Thu, 18 Oct 2007 10:27:49 +0100
From: "Nick Doylend" <bldg-sim at ndoylend.fastmail.fm>
Subject: atrium natural ventilation

Hi, I wonder if anyone can give some advice on this one.  My colleagues
and I are considering a naturally ventilated atrium in the UK.  We're
trying to establish appropriate opening areas at top and bottom to limit
summertime overheating conditions.  At the moment we are using Tas for
this analysis but now suspect its bulk air movement calculations
are not sophisticated enough to model the stratification in the space.

The atrium is occupied at the ground floor and extends up four stories,
it has been zoned into four horizontal slices.  Rather than showing an
increase with height of air temperature we see the opposite - the lower
zone is warmer than the upper zones.  Maybe the ground floor zone has a
higher sensible gain due to the occupants but in a high vertical space,
shouldn't the heat rise to the top of the space?  I wonder if Tas is not
considering the convection across the horizontal zone boundaries or is
overestimating the downward air circulation?

Does anyone have experience of using Tas or alternative techniques for
this kind of analysis?  We would prefer to run a dynamic simulation that
can predict annual overheating, rather than a detailed CFD snapshot in
time.

Any suggestions?

Thanks,

Nick Doylend

PS It would also be interesting to get a show of hands from the Tas
users on this forum - eQUEST seems to be the most popular simulation
tool here judging by the volume of posts.

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  _____  



Date: Thu, 18 Oct 2007 12:22:28 +0100
From: "Jeremy Cockroft" <jeremy at esru.strath.ac.uk>
Subject: RE:  atrium natural ventilation

Nick,
I assume you are modelling a nodal airflow network in TAS, i.e. each
horizontal slice of your atrium is represented by a single node.
That means that buoyancy effects will only be effective on the bulk air
flow through the atrium (upwards if atrium nodes are at a higher air
temperature than external).  That means that at each level (slice), if
you have a net heat loss through the atrium walls, the air will cool as
it rises, which is what you are reporting. To see more complex air flow
effects you would need to include at least two nodes per level, which
would allow air exchange due to localised horizonal air exchanges (not
sure if TAS has this capability; ESP-r does, maybe others), and also the
possibility of an air circulation within the atrium (cooler air
travelling down the external wall, and warmed air up the other side, for
example).  You would have to arrange these nodes intelligently, as you
are making an assumption about how air circulates within the atrium.
ESP-r has a CFD domain for simple (cuboid) spaces, integrated within the
thermal (nodal) nodelling domain, so you could study timewise (dynamic)
evolution of airflows and temperatures.  I'm not aware of other tools
with this capability.
Hope that helps.
Jeremy Cockroft
ESRU
University of Strathclyde
75 Montrose Street
Glasgow G1 1XJ
phone    +44(0)141 548 5765
email       jeremy at esru.strath.ac.uk
website   www.esru.strath.ac.uk

-----Original Message-----
From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Nick
Doylend
Sent: 18 October 2007 10:28
To: BLDG-SIM at gard.com
Cc: mguin at foremanroberts.com
Subject: [BLDG-SIM] atrium natural ventilation

Hi, I wonder if anyone can give some advice on this one.  My colleagues
and I are considering a naturally ventilated atrium in the UK.  We're
trying to establish appropriate opening areas at top and bottom to limit
summertime overheating conditions.  At the moment we are using Tas for
this analysis but now suspect its bulk air movement calculations are not
sophisticated enough to model the stratification in the space.

The atrium is occupied at the ground floor and extends up four stories,
it has been zoned into four horizontal slices.  Rather than showing an
increase with height of air temperature we see the opposite - the lower
zone is warmer than the upper zones.  Maybe the ground floor zone has a
higher sensible gain due to the occupants but in a high vertical space,
shouldn't the heat rise to the top of the space?  I wonder if Tas is not
considering the convection across the horizontal zone boundaries or is
overestimating the downward air circulation?

Does anyone have experience of using Tas or alternative techniques for
this kind of analysis?  We would prefer to run a dynamic simulation that
can predict annual overheating, rather than a detailed CFD snapshot in
time.

Any suggestions?

Thanks,

Nick Doylend

PS It would also be interesting to get a show of hands from the Tas
users on this forum - eQUEST seems to be the most popular simulation
tool here judging by the volume of posts.

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
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  _____  



Date: Thu, 18 Oct 2007 10:55:10 -0400
From: "Doug Kot" <doug at greenroundtable.org>
Subject: Green Building Jobs in Boston - All Levels 

Sorry for the cross postings . . .
-D.

*********************************************
Green Building Jobs in Boston - All Levels
*********************************************

1.  Director of Technology and Innovation

The Green Roundtable, located in downtown Boston, MA, seeks a Director
for its Technology and Innovation services; this senior position offers
a wide range of creative opportunities. The Director oversees project
specific opportunities as well as general tool and resource development
to serve sustainable design strategies. This Director mentors and
provides technical support and in-house review to project management
staff on a wide range of high leverage projects from master planning to
individual buildings of all types. This position also supports the
ongoing development of innovative tools, resources and educational
materials provided to the community through NEXUS, our Green Building
Resource Center. The ideal candidate has experience with building system
analysis (energy and/or daylight modeling), building systems integration
and a solid foundation in building science. A degree and professional
experience in engineering and/or architecture is preferable. This person
can also participate in GRT's educational and policy activities as well,
depending on their level of interest. This is an excellent opportunity
to use a technical background as a tool for innovation and market
transformation. Technical expertise and a passion for sustainability
will provide you with an opportunity for professional satisfaction on
many levels in this position.

Candidate must have:=20
- Minimum of 6 years related experience with an advanced degree; or, a
bachelors degree plus 10 years of related experience
- Solid foundation in building science - ideally bridging architecture
and engineering disciplines
- The highest priority is the ability to provide competent peer review
for building systems (HVAC, lighting, electrical) to critique energy
models and daylight analysis
- Understanding of both traditional and alternative building systems and
building system integration required
- Competencies in site design, civil engineering, and landscape
architecture design a plus
- Professional licensure a plus
- Experience preparing renewable energy feasibility assessments
- Proficiency with construction specifications
- Comfort with life cycle costing and life cycle analysis
- Familiarity with a wide variety of analysis tools, software programs
and comfort level learning new tools
- Experience using LEED and other green building rating systems on
projects;
- Creative, "out of the box" strategic thinking
- Excellent project management skills and attention to detail
- Excellent communication and writing skills
- Ability to teach, mentor and provide ongoing capacity building for
both staff and clients

Interested candidates should send a resume, including a minimum of 3
references and cover letter to info at greenroundtable.org  (word or PDF
format only)

*********************************************=20

2. Project Manager - Green Building Consultant=20

The Green Roundtable, located in downtown Boston, MA, seeks a full-time
project manager green building consultant to provide technical support
on a variety of green building and sustainable planning projects and in
the implementation of green building rating systems (LEED, GGHC, CHPS,
LABS21, etc).=20

Candidates would be consulting directly to owner/client on both process
and technology issues, such as: assisting with design team selection,
shaping cost benefit analysis and building system selection and design
(specific to technology) technical analysis, recommendations and
implementation of all strategies. Your role would specifically require
project management experience, technical review of building systems and
products and LEED facilitation.=20

Interested candidates will also have opportunities to provide training
to stakeholder groups, develop new educational and analytical tools, and
participate in grant-supported public policy work (if desired).

Candidate must have:
-  Minimum of 6 years related experience with an advanced degree; or, a
bachelors degree plus 10 years of related experience
-  Solid foundation in building science - ideally bridging architecture
and engineering disciplines;
-  The highest priority is the ability to provide competent peer review
for building systems (HVAC, lighting, electrical) to critique energy
models and daylight analysis. Understanding of both traditional and
alternative building systems and building system integration required
-  Competencies in site design, civil engineering, and landscape
architecture design a plus
-  Professional licensure a plus
-  Experience preparing renewable energy feasibility assessments a plus
-  Proficiency with construction specifications
-  Comfort with life cycle costing and life cycle analysis
-  Familiarity with a wide variety of analysis tools, software programs
and comfort level learning new tools
-  Experience using LEED and other green building rating systems on
projects;
-  Creative, "out of the box" strategic thinking
-  Excellent project management skills and attention to detail
-  Excellent communication and writing skills

Interested candidates should send a resume, including a minimum of 3
references and cover letter to info at greenroundtable.org  (word or PDF
format only)
=20
*********************************************

3. Project Assistant

This entry-level position supports GRT's Project Management staff.  The
candidate will be exposed to many different scales, strategies, design
challenges and project types. A background in architecture or
engineering is preferred. This position supports all of our projects
including those that are using the LEED rating system. Our work includes
both credit calculations and analysis as well as coaching teams to
execute documentation and build capacity using and administering LEED.
Familiarity with LEED preferable, but assumption is that this is a
learning opportunity as well.

Candidate must have:
-  Bachelor's degree in allied field (architecture, engineering,
construction management)=20
-  Good organizational skills and attention to detail
-  Takes initiative and can be self directed, while working closely with
one or two supervisors
-  Ability and passion for learning and ability to absorb new concepts
-  Good interpersonal and communication skills to be able to interact
with team members and facilitate and administer project management of
LEED.
-  Analytical skills and good Microsoft Excel skills

Interested candidates should send a resume, including a minimum of 3
references and cover letter to info at greenroundtable.org   (word or PDF
format only)

*********************************************

Company Background:

The Green Roundtable's mission is to mainstream green development and
ultimately become obsolete. GRT's market transformation strategy relies
on innovative programs in education, policy and technical assistance.
These programs help owners and developers understand and communicate
their goals, build capacity in design professionals to meet green
building expectations, empower consumers to ask critical questions and
advise policy initiatives to require green development so that
eventually, it becomes business as usual. GRT is the Massachusetts
Affiliate of the US Green Building Council.
=20
GRT's technical assistance uses an integrative design process to bring
greater clarity and collaboration to decision-making and raise the bar
on performance and health achievements. One of GRT's greatest tools is
NEXUS: The Green Building Resource, which provides the community with
access to resources and information to educate themselves and broaden
their mindsets. Technical assistance staff serve both projects as well
as resources offered through NEXUS.

GRT consulting projects range from master planning to existing
building/facility asset management and individual building projects of
every type and scale. Interested candidates will also have opportunities
to provide training, develop new educational and analytical tools, and
participate in public policy work in local governments and institutions.
This opportunity is uniquely satisfying for individuals who like to be
active in a variety of different kinds of work and use technical
expertise to truly participate in market transformation through policy
and education as well as consulting.
=20
GRT currently has three positions open in its technical assistance team,
a Director of Technology and Innovation, Project Manager and Project
Assistant.

*********************************************


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  _____  



Date: Thu, 18 Oct 2007 10:25:12 -0500
From: David Bradley <bradley at tess-inc.com>
Subject: TRNSYS Training

Dear Colleagues,

My apologies for cross postings.

A TRNSYS Training course will be held in Madison, WI on February 
25-27, 2008. The course will cover the following topics:

Introduction to Energy Simulations with TRNSYS
Simulating Building Energy Use with TRNSYS
Creating New Components
Creating Distributable TRNSYS Simulations with TRNSED

An additional day will be offered on working with NIST's CONTAM-W 
software to perform air flow and natural ventilation studies in 
conjunction with TRNSYS on February 28th.

Course participants will receive a free copy of TRNOPT, a tool that 
allows users to perform optimizations of TRNSYS input files. Anyone 
interested in more information about the course can check the course 
home page and download a registration form on the web at 
http://www.tess-inc.com/trnsys/schedule. Please do not hesitate to 
contact us if you have any questions.

Kind regards,
  David Bradley


****************************************************************************************
Thermal Energy System Specialists (TESS), LLC
David BRADLEY                           2916 Marketplace Drive - Suite 104
Partner                                        Madison, WI 53719
Phone: (608) 274-2577 USA
Fax: (608) 278-1475
E-mail: bradley at tess-inc.com
Web Pages:  http://www.tess-inc.com     and      http://www.trnsys.com

"Providing software solutions for today's energy engineering projects"
****************************************************************************************



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  _____  



Date: Thu, 18 Oct 2007 13:55:32 -0400
From: "Keith Lane" <keith_lane at g-g-d.com>
Subject: GSHP System Pump Error


I am modeling a 46,200 hotel with a geothermal well heat pump system in
the detailed interface of eQUEST and am running into a few problems. I
am fairly new to the program so please forgive my ignorance. I searched
the previous threads and could not find any solutions and would highly
appreciate any assistance.

=20

*	For heating only zones, there will be electric unit heaters
installed. ASHRAE Std. 90.1-2004 states "Where no cooling system exists
or no cooling system has been specified, the cooling system shall be
identical to the system modeled in the baseline design." For such spaces
I have specified a packaged single zone unit. Specifying electric heat
and a water cooled condenser connected to the GSHP Loop. Is this the
correct approach?

=20

*	When I go to perform a simulation I am prompted with "PUMPd
Error: PUMP design input is unreasonable Check values." The GSHP system
has (2) pumps and I have input their specifications per design. Does
anyone have any suggestions? Could this be due to the electric unit
heaters being modeled with cooling, thus increasing GPM?

=20

*	I am also having trouble with my DHW Loop Pumps. I receive an
error stating: "Pump: DHW Loop Pumps has user specified parameters that
force the mechanical efficiency to be unreasonable. Check input or allow
the program to calculate the kW. Calculated mechanical efficiency=3D
0.071."  Once again I have entered the pumps' specifications per design
documents.

=20

Thank you,

=20

Keith Lane, LEED AP

Mechanical Engineer

Garcia.Galuska.DeSousa

Consulting Engineers                     Inc.                       =20

370 Faunce Corner Road, Dartmouth, MA 02747=20

p.508.998.5700                          f. 508.998.0883

=20



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  _____  



Date: Thu, 18 Oct 2007 13:30:09 -0700 (PDT)
From: ruju rathod <ruju_r at yahoo.com>
Subject: Complex shading device in Ecotect

Dear All,
As a new user to Ecotect, I would like to know how to model a complex shading device.
   
  I have started by creating a box that is 11' wide and 20'long. The box is 14' in height and has concrete-asphalt on the roof and concrete slab on ground for the floor. The walls are timber frame except the south wall which is single glazed_alum frame.
  I would like to find out the shading percentage on a particular day of an integrated system which includes overhangs or external louvres at unequal spacing or angled louvres supported by fins on either side.
   
  The shading mask seems to believe that the window is 100% shaded at all times. However, in a climate like Houston which is the site for this Ecotect experiment and the device including 12 inch fins on either side and 12 inch depth overhangs above 10ft from the floor is certainly inadequate.
   
  Please feel free to send your suggestions.
   
  Thanks,
  Ruju. 




Ruju Rathod 
M.S(Sustainable Design)
Kirksey (www.kirkseygreen.com)
Houston,TX.
 __________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 


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  _____  



Date: Thu, 18 Oct 2007 16:03:16 -0500
From: "Jon Evans" <jevans at sustaineng.com>
Subject: RE: [Campus Chilled Water] eQUEST: Central Chiller for Baseline?


Sam and others,

 

I have a follow-up question related to your response on 9/25 to purchased
chilled water and LEED modeling. 

 

I have a baseline building using ASHRAE 90.1 System 1 (PTAC Units). The
proposed building is using campus chilled water and fan coil units or water
source heat pumps.  Do I use electric as the source for the PTAC cooling, or
the campus chilled water? Using campus chilled water with PTAC units is not
a realistic option, but it seems like 90.1/LEED requires this (Table 11.3.2A
in 90.1-2004)- would USGBC consider this fuel switching?

 

Also, as a general survey, what are the going rates for campus chilled water
and steam?  I have seen ~$0.70/therm chilled water (generated by absorption
chillers) and $0.35/therm for steam for a college dormitory. I think these
rates will vary by campus and end use.

 

Thanks for your guidance in advance.

 

-Jon 

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Sam Mason
Sent: Tuesday, September 25, 2007 8:31 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] eQUEST: Central Chiller for Baseline?

 

Yoko,

In note 5 under Table 11.3.2A, 90.1-2004 says for systems using purchased
chilled water, no chillers shall be modeled and CHW costs shall be
determined using the adopting authority's utility rates.  For both the
baseline and proposed buildings, you would not include central chillers and
instead use purchased chilled water.

 

Sam

 

















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  _____  



Date: Thu, 18 Oct 2007 14:09:21 -0700 (PDT)
From: Adam Jackaway <adamjackaway at yahoo.com>
Subject: Ecotect skylights

My students are working on skylighting designs for simple models in Ecotect=
. They are starting with a simple box with no windows. They insert a horizo=
ntal window into the ceiling plane. Illuminance calculations look reasonabl=
e. They then insert a roof zone on top of the box, intending to eventually =
make a 'lay-light' scheme. But before inserting any glazing into the roof z=
one, they run the illuminance calcs to check the roof was inserted properly=
 - expecting to see no daylight in the lower box. Yet there is a low level =
wash on the interior. =0A=0AAnyone run into this before? Any suggestions?=
=0A=0AThanks,=0A=0AAdam

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  _____  



Date: Thu, 18 Oct 2007 18:39:05 -0400
From: "Alec Stevens" <astevens at dmiinc.com>
Subject: eQuest - error CHW temp vs. LAT


Hi,

eQuest is giving us an error when modeling a chiller plant that has a =
high
delta-T.  The chilled water temps are 41=BAF / 57=BAF, and the =
anticipated
discharge temp off the coil is 55=BAF.  This would be accomplished by a
relatively deep coil.  eQuest does not like the fact that the return CHW
Temp is higher than the leaving air temp.  It would like to see at least =
a
6=BAF approach between the two. =20

=20

Any suggestions on how to satisfy eQuest while maintaining a good =
simulation
of the CHW pumping energy and chiller compressor performance?

=20

Thanks for any suggestions.

=20

Sincerely,
Alec Stevens, PE, LEED AP
DMI

35 Walnut Street, Wellesley, MA 02481
p: 781-431-1100 x11 f: 781-431-1109
e: astevens at dmiinc.com

=20



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  _____  



Date: Thu, 18 Oct 2007 18:00:35 -0500
From: "Bill Talbert" <btalbert at aeieng.com>
Subject: Re:  [Campus Chilled Water] eQUEST: Central Chiller for Baseline?


Jon,
 
You indicate your baseline system is System 1 - PTAC. I assume this is
per Table G3.1.1A in Appendix G. If you are simulating building energy
performance per Appendix G (i.e. LEED), then your baseline cooling type
would be Direct Expansion per Table G3.1.1B. Your proposed design
cooling source will be chilled water and you will be comparing it to a
baseline that is using electricity to provide DX cooling. Table G3.1.3.7
referenced in the original email from Yoko only applies if your baseline
system per Appendix G is System 7 or 8, so it is possible to compare a
baseline DX system with a proposed design on a campus chilled water
loop.
 
Table 11.3.2A is only applicable to the Energy Cost Budget approach
used to demonstrate compliance with A90.1. This is not applicable to
LEED unless you are only trying to meet Prerequisite 2 (now largely
irrelevant unless your project was registered before June 26, 2007 and
doesn't have to meet the mandatory EA Credit 1 - 2 points). If however,
this is the path you are on, then you would need to select your baseline
per Figure 11.3.2. System 1 as defined in Chapter 11 is a VAV w/fan
powered boxes. Based on your proposed design system description, it
looks like you would be using System 6 per Chapter 11. 
 
Bill
 
 
 
 
 
 
Bill Talbert, PE, LEED® AP
Mechanical Systems
Phone: (608) 441-6677
E-mail: btalbert at aeieng.com 

Affiliated Engineers Inc.
5802 Research Park Blvd.
Madison, WI. 53719
Tel. (608) 238-2616
Fax. (608) 238-2614

>>> "Jon Evans"  10/18/2007 4:03 PM >>>

Sam and others,
 
I have a follow-up question related to your response on 9/25 to
purchased chilled water and LEED modeling. 
 
I have a baseline building using ASHRAE 90.1 System 1 (PTAC Units). The
proposed building is using campus chilled water and fan coil units or
water source heat pumps.  Do I use electric as the source for the PTAC
cooling, or the campus chilled water? Using campus chilled water with
PTAC units is not a realistic option, but it seems like 90.1/LEED
requires this (Table 11.3.2A in 90.1-2004)- would USGBC consider this
fuel switching?
 
Also, as a general survey, what are the going rates for campus chilled
water and steam?  I have seen ~$0.70/therm chilled water (generated by
absorption chillers) and $0.35/therm for steam for a college dormitory.
I think these rates will vary by campus and end use.
 
Thanks for your guidance in advance.
 
-Jon 

From:BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Sam
Mason
Sent: Tuesday, September 25, 2007 8:31 AM
To: BLDG-SIM at gard.com 
Subject: [BLDG-SIM] eQUEST: Central Chiller for Baseline?

 
Yoko,
In note 5 under Table 11.3.2A, 90.1-2004 says for systems using
purchased chilled water, no chillers shall be modeled and CHW costs
shall be determined using the adopting authority’s utility rates.  For
both the baseline and proposed buildings, you would not include central
chillers and instead use purchased chilled water.
 
Sam
 
















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  _____  



Date: Fri, 19 Oct 2007 14:23:41 +1300
From: "Michael Donn" <Michael.Donn at vuw.ac.nz>
Subject: RE:  Ecotect skylights


Gidday=20
=20
We have run into issues like this before with Ecotect - to the point
where I now have a KISS (Keep it simple Stupid) lecture in reserve for
my students to review the difference between visual and mathematical
modelling
=20
Only guessing, because I have not encountered this specific issue. But I
suspect that this is also one of these visual logic vs mathematical
model issues. For example, we had students who have in the past with a
school gymnasium modelled some bleachers / upper level spectator area
using the same tools they modelled the general gym form. With the simple
gym form, the sound ray trace worked believably. With the extra seating
area modelleed so that it looked visually acceptable, the sound stayed
inside the bleacher/balcony form. What had happened was that a second
zone (bleacher) had been created inside the first (gym)  zone and the
acoustic (mathematical) model just worked on the inner zone definition,
no matter where in the larger, outer zone the visuals showed the sound
source to have been placed.=20
=20
I am imagining that there is a mathematical model (lumen method?)
linking your 'simple box' zone to the sky definition; adding another
'roof' zone that appears visually 'above' the first 'simple box' zone
does not remove that mathematical link. You would need explicitly to
change the horizontal window definition to be some form of interzone
device...=20
=20
At some point in these type of calc's you might consider that the
Ecotect quick calculation model has reached its limits and then you
would use it to export to a more capable modeller - the new Control
panel in Ecotect is a great way of running Radiance!?
=20
M
=20

Michael Donn                                                      =20
Associate Dean Research
Director Centre for Building Performance Research
School of Architecture =20
Victoria University      +64 4 463 6221  work
PO Box 600              +64 21 611 280  mobile
Wellington                +64 4 463 6204  work fax
New Zealand             +64 21 611 594  mobilefax

=20

http://www.vuw.ac.nz/architecture/staff/academics/michael-donn.aspx=20









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End BLDG-SIM at GARD.COM message digest 10/19/2007 03:01 (#2007-1044)
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