[Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air velocity on thermal comfort

Eric Roberts eric at zed-uk.com
Thu Dec 17 04:37:01 PST 2009


Sanyogita

 

Try upgrading to the latest V2.1 release 

 

Eric

 

 

From: sanyogita manu [mailto:sanyogitamanu at yahoo.com] 
Sent: 17 December 2009 11:41
To: Eric Roberts; Andy Tindale
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air
velocity on thermal comfort

 

Hi Eric,

 

I dont know why but I still dont see it anywhere. Is there some some other
precondition within the program or model options for it to appear??

(snapshot attached)

 

Thanks for your patience,

 

Sanyogita

 

Sanyogita Manu
Energy Efficiency Research Associate
USAID ECO-III Project
International Resources Group (IRG)
AADI Building, Lower Ground Floor
2, Balbir Saxena Marg
Hauz Khas, New Delhi 110016
Tel: +91-11-2685-3110
M: +91-9999-910-554
Email: smanu at irgssa.com

 

 

  _____  

From: Eric Roberts <eric at zed-uk.com>
To: sanyogita manu <sanyogitamanu at yahoo.com>; Andy Tindale
<Andy at designbuilder.co.uk>
Cc: bldg-sim at lists.onebuilding.org
Sent: Thu, December 17, 2009 4:09:50 PM
Subject: RE: [Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air
velocity on thermal comfort

Sanyogita

 

The below screen shot will show you where the comfort velocity is in the
model options tool (spanner icon) under simulation tab in the advanced
option

 

Operative temperature description can be found here:
http://www.designbuilder.co.uk/programhelp/calculation_options.htm

 

Eric

 

 

 

 

 

 

 

 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of sanyogita manu
Sent: 17 December 2009 07:12
To: Andy Tindale
Cc: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air
velocity on thermal comfort

 

Hi Andy,

 

I could not find the input field for specifying velocity anywhere. Is it
something to do with the version; I am using 2.0.4.002. And one more
question: when we use the Operative temperature control in DesignBuilder, it
takes radiant fraction of 0.5 by default, and its not possible to change it,
am I right?

 

Thanks a lot,
 

Sanyogita


Energy Efficiency Research Associate
USAID ECO-III Project
International Resources Group (IRG)
AADI Building, Lower Ground Floor
2, Balbir Saxena Marg
Hauz Khas, New Delhi 110016
Tel: +91-11-2685-3110
M: +91-9999-910-554
Email:  <mailto:smanu at irgssa.com> smanu at irgssa.com

 

 

  _____  

From: Andy Tindale <Andy at designbuilder.co.uk>
To: sanyogita manu <sanyogitamanu at yahoo.com>
Cc: "bldg-sim at lists.onebuilding.org" <bldg-sim at lists.onebuilding.org>
Sent: Wed, December 16, 2009 9:27:41 PM
Subject: RE: [Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air
velocity on thermal comfort

Hi Sanyogita,

 

Just to mention that in DesignBuilder, you can define the velocity to be
used for the comfort calculations on the Simulation tab of the model options
dialog, under the Advanced header. I tried changing from the default air
velocity from 0.137 m/s to 2 m/s and obtained very different results for all
comfort indices, including Fanger PMV.

 

Regards,

 

Andy

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of sanyogita manu
Sent: 16 December 2009 06:13
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Query on DesignBuilder and EnergyPlus: Impact of air
velocity on thermal comfort

 

Hi, 

I am trying to model the impact of ceiling fans on thermal comfort in a
warm-humid climate, for a naturally ventilated building. Intial simulation
runs obviously show a lot of discomfort with PMV going upto 5.5 during peak
summer. We want to model ceiling fans so that the impact of air velocity on
thermal comfort is captured. Naturally this wont lead to achieving thermal
comfort conditions in the space but we feel that it should at least result
in PMV coming down to 4-4.5. I am not sure if doing this is possible in
DesignBuilder but I think one can specify an object called AirVelocity
schedule in EnergyPlus, where one can input air velocity in m/s in one of
the fields (the current EPlus default being 0.137). I want to know that if
we modify (increase) the value of air velocity to about 0.7 (for ceiling
fans), would it be used for comfort calculations? I thought the Fanger
comfort model algorithms use air velocity for calculations but I can't see
that happening anywhere in the Eplus Engineering reference, which could also
have been a resultant of my limited understanding of the subject matter. I
also noticed that the Pierce model takes air velocity into account. Does
this mean that we should rather look at the Pierce model rather than the
Fanger model in order to arrive at an adaptive model of thermal comfort?
What we basically want to do is to make sure that the increased air velocity
is used for calculation of PMV in EnergyPlus to model the impact of ceiling
fans. 

I would be really grateful for any help. 

Regards, 
 

Sanyogita Manu
Energy Efficiency Research Associate
USAID ECO-III Project
International Resources Group (IRG)
Hauz Khas, New Delhi 110016
Email: smanu at irgssa.com

 

 

 

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