[esp-r] Re: Window u-value temperature dependency in ESPr
Achim Geissler
achim.geissler at intergga.ch
Fri Feb 5 09:53:43 GMT 2010
Hi Francesco
one aspect that I remembered after the post is that I think the CFCs are
restricted to vertical surfaces, for now. As you have a roof window, it may
after all not be a solution.
However, as one can enter three resistances for a “normal” TMC and “the
other two” are called heat flux upwards and downwards, it should be a good
approximation. However, I have never checked the code if the resistance
value chosen is actually a function of the heat flux direction (and would
then change for a roof light during run time, usually) or is linked to the
“position” of the surface (i.e. “ceil” or “floor”).
Regards
Achim
From: esp-r-bounces at lists.strath.ac.uk
[mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Francesco Frontini
Sent: Freitag, 5. Februar 2010 10:28
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Re: Window u-value temperature dependency in ESPr
Thank you Achim,
I downloaded it and looks fine.
I already work with this CFC model but I forgot that Bartosz implemented
also the temperature dependency of the glazing cavity!
Regards
Francesco
2010/2/2 <esp-r-request at lists.strath.ac.uk>
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Today's Topics:
1. Window u-value temperature dependency in ESPr
(Francesco Frontini)
2. Re: Window u-value temperature dependency in ESPr (Achim Geissler)
3. World turned upside down.... (Bob Irving)
----------------------------------------------------------------------
Message: 1
Date: Tue, 2 Feb 2010 14:51:58 +0100
From: Francesco Frontini <francesco.frontini at polimi.it>
Subject: [esp-r] Window u-value temperature dependency in ESPr
To: esp-r at lists.strath.ac.uk
Message-ID:
<d2985fe1002020551w688bb21cg3c6fab7215eda721 at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
Dear ESP-r users,
I have a question regarding how ESP-r calculates the properties of a glass
unit (for example a double glaze unit with argon gap).
I red several discussions about the capability of ESP-r of reading and
importing WIS or Window data file, but for me is not clear which kind of
data espr effectively read.
My knowledge is that, when we specify a glass construction we have to give
the resistances of the air gap between the glass panes (that is a fix value)
in the construction library and then define the optical properties in the
optic database (ESPr ask for the angle dependence absorptances of the
different panes and the angle dependence transmittance of the different
panes). That?s all! Am I wrong?
Now comes the question?
How does ESPr calculates the temperature dependency of the air (or gas) gap
resistance between the panes? It is not possible to define the emissivity of
both glass pane surfaces?
I know that TRNSYS uses the Window 4 model (but, if I correctly remember,
TRNSYS is not able to consider not standard emissivities for the outer
surfaces).
I have this question because I am modelling a family house room under a
tilted roof. The window is a roof window (like Velux). I think that, for
such cases, it is relevant to model correctly the temperature dependency
(also the wind dependency) of the gas-gap resistance.
Any help is appreciated.
Francesco
--
Dr. Francesco Frontini, MEng PhD in Buildings Engineering
----------------------------------------
Fraunhofer Institut f?r Solare Energiesysteme ISE
Heidenhofstr. 2, 79110 Freiburg, Germany
M1: [+39] 333-3097826
M2: [+49] (0)1522-1624691
Phone: [+49] (0)7614588-5358
FAX: [+49] (0)7614588-9358
@1: francesco.frontini at ise.fraunhofer.de
@2: francesco.frontini at polimi.it
----------------------------------------
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Message: 2
Date: Tue, 2 Feb 2010 15:35:58 +0100
From: "Achim Geissler" <achim.geissler at intergga.ch>
Subject: [esp-r] Re: Window u-value temperature dependency in ESPr
To: "'Francesco Frontini'" <francesco.frontini at polimi.it>,
<esp-r at lists.strath.ac.uk>
Message-ID: <001001caa415$09e37310$1daa5930$@geissler at intergga.ch>
Content-Type: text/plain; charset="iso-8859-1"
Dear Francesco
you have it right for the ?traditional? MLC. With this construction type,
the gap resistance is not temperature-dependant. However, as of release 11.7
(I think it was), there is a new type called ?CFC? (Complex Fenestration
Constructions?). This type uses the actual emissivity of the surfaces and
calculates temperature-dependant properties for the IGU gap (and has some
other quite handy frills). The underlying model / theory etc. is well
described in Bartosz Lomanowski?s thesis, available at ESRU.
Regards
Achim
From: esp-r-bounces at lists.strath.ac.uk
[mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Francesco Frontini
Sent: Dienstag, 2. Februar 2010 14:52
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Window u-value temperature dependency in ESPr
Dear ESP-r users,
I have a question regarding how ESP-r calculates the properties of a glass
unit (for example a double glaze unit with argon gap).
I red several discussions about the capability of ESP-r of reading and
importing WIS or Window data file, but for me is not clear which kind of
data espr effectively read.
My knowledge is that, when we specify a glass construction we have to give
the resistances of the air gap between the glass panes (that is a fix value)
in the construction library and then define the optical properties in the
optic database (ESPr ask for the angle dependence absorptances of the
different panes and the angle dependence transmittance of the different
panes). That?s all! Am I wrong?
Now comes the question?
How does ESPr calculates the temperature dependency of the air (or gas) gap
resistance between the panes? It is not possible to define the emissivity of
both glass pane surfaces?
I know that TRNSYS uses the Window 4 model (but, if I correctly remember,
TRNSYS is not able to consider not standard emissivities for the outer
surfaces).
I have this question because I am modelling a family house room under a
tilted roof. The window is a roof window (like Velux). I think that, for
such cases, it is relevant to model correctly the temperature dependency
(also the wind dependency) of the gas-gap resistance.
Any help is appreciated.
Francesco
--
Dr. Francesco Frontini, MEng PhD in Buildings Engineering
----------------------------------------
Fraunhofer Institut f?r Solare Energiesysteme ISE
Heidenhofstr. 2, 79110 Freiburg, Germany
M1: [+39] 333-3097826
M2: [+49] (0)1522-1624691
Phone: [+49] (0)7614588-5358
FAX: [+49] (0)7614588-9358
@1: francesco.frontini at ise.fraunhofer.de
@2: francesco.frontini at polimi.it
----------------------------------------
The information transmitted is intended only for the person or entity to
which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
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Message: 3
Date: Tue, 2 Feb 2010 16:11:27 +0000
From: Bob Irving <bob.irving at brookes.ac.uk>
Subject: [esp-r] World turned upside down....
To: esp-r at lists.strath.ac.uk
Message-ID: <2B29137A-B225-4C32-99B9-5CD5A5E399C2 at brookes.ac.uk>
Content-Type: text/plain; charset="us-ascii"
Attached is a screen shot of the first zone I have created in a model.
After entering the vertices of the zone, I changed the names and added
constructions for two walls and then did the same for the Base, with the
addition of linking it to the ground.
Returning to the wireframe, I now observe that the Base, renamed to
Bdrm1_floor, is at the top of the drawing and Top-8 is at the bottom.
I've not rotated the drawing at all (honest!)
Please advise!
Bob Irving
PhD researcher
Oxford Inst of Sustainable Development
Oxford Brookes University
01865 484201
01285 650281
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--
Dr. Francesco Frontini, MEng PhD in Buildings Engineering
----------------------------------------
Fraunhofer Institut für Solare Energiesysteme ISE
Heidenhofstr. 2, 79110 Freiburg, Germany
M1: [+39] 333-3097826
M2: [+49] (0)1522-1624691
Phone: [+49] (0)7614588-5358
FAX: [+49] (0)7614588-9358
@1: francesco.frontini at ise.fraunhofer.de
@2: francesco.frontini at polimi.it
----------------------------------------
The information transmitted is intended only for the person or entity to
which it is addressed and may contain confidential and/or privileged
material. Any review, retransmission, dissemination or other use of, or
taking of any action in reliance upon, this information by persons or
entities other than the intended recipient is prohibited. If you receive
this in error, please contact the sender and delete the material from any
computer.
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