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Re: [TRNSYS-users] Total heating demand (??)

Dear Wang,
Regarding your first question: I suspect the thermal capacity of the floor to cause the difference between case 2 and 3. Simulate a larger time period and this effect should get smaller.
About your second question, floor or wall heating systems are more efficient than radiator based heating systems because they demand lower inlet (or forward) temperatures. By this boiler (and potential storage) efficiency increases. Since you do not simulate any heat generation, these effects do not occur in your simulation. I expect the Qheat of case 1 to be the real heat demand and QALFL_Inlet of case 2 to be the heat delivered to the room by the active layer. 

Hope this helps.

Best regards,
Jochen


trnsys-users-request@cae.wisc.edu schrieb:

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Today's Topics:

   1. Total heating demand (??)
   2. Re: question about wall gain (Knut Erik Enerstvedt)
   3. Re: question about wall gain (salim mokraoui)

------------------------------------------------------------------------

Betreff:
[TRNSYS-users] Total heating demand
Von:
王洋 <wanghongyang1767@gmail.com>
Datum:
Thu, 6 Jan 2011 21:16:10 +0100
An:
trnsys-users@cae.wisc.edu

An:
trnsys-users@cae.wisc.edu


Dear all,

 Happy new year!

 I have a question about calculating total heating demand:

There is one same room to keep indoor temperature as 20°C one day 24 hours,
the initial indoor temperature is 20°C, there is no infiltration no other
internal gains in the room. I used 3 different methods to calculate total
heating demand of one day, separately.

1.First is heating in TRNBuild: after using the INTEGRATOR TYPE 46, the
QHEAT is about 34314 kJ.

2.Second is floor heating(active layer): after using the INTEGRATOR TYPE 46,
the QALFL_Inlet is about 33680.7kJ.

3.Third is still floor heating(active layer): after using the INTEGRATOR
TYPE 46, but I used Q=CwaterMwater(Tinlet-Toutlet), the result of Q is
144639kJ.

My question is: 1) To 2 and 3: Why is the difference is so large? 3 is
almost 4 times than 3? I will get the total heating demand, which one is
right? Why? What's different of both of them?

2) If 3 is right. Generally, the floor heating should be more energy-saving
than common heating. But here result is absolutely opposite. The common
heating is more energy-heating. Why? Here what difference of common heating
and floor heating?

Many thanks!

Br.

wang
在 2011年1月5日 下午7:55，王洋 <wanghongyang1767@gmail.com>写道：


Dear all,

 Happy new year!

 I have a question about calculating total heating demand:

There is one same room to keep indoor temperature as 20°C one day 24 hours,
the initial indoor temperature is 20°C, there is no infiltration no other
internal gains in the room. I used 3 different methods to calculate total
heating demand of one day, separately.

1.First is heating in TRNBuild: after using the INTEGRATOR TYPE 46, the
QHEAT is about 34314 kJ.

2.Second is floor heating(active layer): after using the INTEGRATOR TYPE
46, the QALFL_Inlet is about 33680.7kJ.

3.Third is still floor heating(active layer): after using the INTEGRATOR
TYPE 46, but I used Q=CwaterMwater(Tinlet-Toutlet), the result of Q is
144639kJ.

My question is: 1) To 2 and 3: Why is the difference is so large? 3 is
almost 4 times than 3? I will get the total heating demand, which one is
right? Why? What's different of both of them?

2) If 3 is right. Generally, the floor heating should be more energy-saving
than common heating. But here result is absolutely opposite. The common
heating is more energy-heating. Why? Here what difference of common heating
and floor heating?

Many thanks!

Br.

wang


在 2011年1月5日 下午2:38，王洋 <wanghongyang1767@gmail.com>写道：

Dear all,

 Happy new year!

 I have a question about calculating total heating demand:

There is one same room to keep indoor temperature as 20°C one day 24
hours, the initial indoor temperature is 20°C, there is no infiltration no
other internal gains in the room. I used 3 different methods to calculate
total heating demand of one day, separately.

1.First is heating in TRNBuild: after using the INTEGRATOR TYPE 46, the
QHEAT is about 34314 kJ.

2.Second is floor heating(active layer): after using the INTEGRATOR TYPE
46, the QALFL_Inlet is about 33680.7kJ.

3.Third is still floor heating(active layer): after using the INTEGRATOR
TYPE 46, but I used Q=CwaterMwater(Tinlet-Toutlet), the result of Q is
144639kJ.

My question is: 1) To 2 and 3: Why is the difference is so large? 3 is
almost 4 times than 3? I will get the total heating demand, which one is
right? Why? What's different of both of them?

2) If 3 is right. Generally, the floor heating should be more
energy-saving than common heating. But here result is absolutely opposite.
The common heating is more energy-heating. Why? Here what difference of
common heating and floor heating?

Many thanks!

Br.

wang



2011/1/4 <trnsys-users-request@cae.wisc.edu>


Send TRNSYS-users mailing list submissions to
       trnsys-users@cae.wisc.edu

To subscribe or unsubscribe via the World Wide Web, visit
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or, via email, send a message with subject or body 'help' to
       trnsys-users-request@cae.wisc.edu

You can reach the person managing the list at
       trnsys-users-owner@cae.wisc.edu

When replying, please edit your Subject line so it is more specific
than "Re: Contents of TRNSYS-users digest..."

Today's Topics:

  1. optimization problems using trnopt in Windows 7 OS (Dapeng Li)


---------- 已转发邮件 ----------
From: Dapeng Li <jiap1120@gmail.com>
To: TRNSYS-users@cae.wisc.edu
Date: Tue, 4 Jan 2011 18:00:38 +0100
Subject: [TRNSYS-users] optimization problems using trnopt in Windows 7
OS
Dear all,

I want to do optimization using trnsys, trnopt and genopt in* Windows 7
OS. *But when I run the example in the directory of "C:\Program
Files\Trnsys16_1\Optimization", I got a error message in Genopt interface
that is enclosed in the attachment.

The version I use is listed below: TRNSYS version 16.01.0003, trnopt
version 2.1.0.52, genopt version 2.1.0 June 18, 2008.

PS: I ever did optimization in XP OS, and it work well.

Thanks in advance.

With kind regards,

Dapeng Li



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------------------------------------------------------------------------

Betreff:
Re: [TRNSYS-users] question about wall gain
Von:
Knut Erik Enerstvedt <knut.erik.enerstvedt@gmail.com>
Datum:
Fri, 7 Jan 2011 09:18:20 +0100
An:
duffy@tess-inc.com, salim.mokraoui@lermab.uhp-nancy.fr, trnsys-users@cae.wisc.edu 

An:
duffy@tess-inc.com, salim.mokraoui@lermab.uhp-nancy.fr, trnsys-users@cae.wisc.edu 


Dear Matt and Salim,


One example of usage for "wall gain" is when you have defined a boundary
wall with known boundary temperature, but also want to take into account
solar gain from windows on that wall. You can not (at least in TRNSYS 16)
define windows in the normal manner on boundary walls. For example, if you
are modelling a zone adjacent to a highly glazed building with known
temperature, and a glass wall separates the two. Then you can use "wall
gain" to impose the solar heat flux from the adjacent building on the
boundary wall.


Best regards,

Knut Erik Enerstvedt




Dear Salim,



To the best of my knowledge, and according to the documentation, it is

indeed an energy flux to the inside wall surface. When does one >use this, I
am not exactly sure. Perhaps when there is chimney in a wall with hot
exhaust gases that is causing a gain to the zone?


Best regards,



Matt




*>----- Original Message -----*
*>From:* "salim mokraoui" <salim.mokraoui@lermab.uhp-nancy.fr>
*>Sent:* Wed, January 5, 2011 9:23
*>Subject:* [TRNSYS-users] question about wall gain


Dear trnsys users,





In zone window of trnbuild, what does wall gain means actually, is it a

density flux that we impose at the inside surface of the wall ?




Many thanks





Salim MOKRAOUI



Faculté des sciences de Nancy - LERMAB



BP 239



54506 Vandoeuvre.



Tél 03 83 68 48 44 - mél salim.mokraoui@lermab.uhp-nancy.fr



------------------------------------------------------------------------

Betreff:
Re: [TRNSYS-users] question about wall gain
Von:
"salim mokraoui" <salim.mokraoui@lermab.uhp-nancy.fr>
Datum:
Fri, 7 Jan 2011 10:06:01 +0100
An:
"'Knut Erik Enerstvedt'" <knut.erik.enerstvedt@gmail.com>, <duffy@tess-inc.com>, <trnsys-users@cae.wisc.edu> 

An:
"'Knut Erik Enerstvedt'" <knut.erik.enerstvedt@gmail.com>, <duffy@tess-inc.com>, <trnsys-users@cae.wisc.edu> 


Dear Erik and Matt,
Thank you very much for your answers. 
I can understand that this wall gain concerns only a radiative gains, is it
right ?


Best regards
De : Knut Erik Enerstvedt [mailto:knut.erik.enerstvedt@gmail.com] Envoyé : vendredi 7 janvier 2011 09:18 
À : duffy@tess-inc.com; salim.mokraoui@lermab.uhp-nancy.fr;
trnsys-users@cae.wisc.edu
Objet : Re: [TRNSYS-users] question about wall gain


Dear Matt and Salim,


One example of usage for "wall gain" is when you have defined a boundary
wall with known boundary temperature, but also want to take into account
solar gain from windows on that wall. You can not (at least in TRNSYS 16)
define windows in the normal manner on boundary walls. For example, if you
are modelling a zone adjacent to a highly glazed building with known
temperature, and a glass wall separates the two. Then you can use "wall
gain" to impose the solar heat flux from the adjacent building on the
boundary wall.


Best regards,

Knut Erik Enerstvedt


Dear Salim,



To the best of my knowledge, and according to the documentation, it is

indeed an energy flux to the inside wall surface. When does one >use this, I
am not exactly sure. Perhaps when there is chimney in a wall with hot
exhaust gases that is causing a gain to the zone?


Best regards,



Matt






----- Original Message -----
From: "salim mokraoui" <salim.mokraoui@lermab.uhp-nancy.fr> Sent: Wed, January 5, 2011 9:23 
Subject: [TRNSYS-users] question about wall gain



Dear trnsys users,



In zone window of trnbuild, what does wall gain means actually, is it a

density flux that we impose at the inside surface of the wall ?


Many thanks



Salim MOKRAOUI



Faculté des sciences de Nancy - LERMAB



BP 239



54506 Vandoeuvre.



Tél 03 83 68 48 44 - mél salim.mokraoui@lermab.uhp-nancy.fr
------------------------------------------------------------------------ 

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TRNSYS-users@cae.wisc.edu
https://mailman.cae.wisc.edu/listinfo/trnsys-users


--
_________________________________________________

Dipl.-Ing. (FH) Jochen Döll
Dept. Thermal Systems and Buildings

Fraunhofer-Institut für Solare Energiesysteme ISE
Heidenhofstrasse 2, 79110 Freiburg, Germany

Phone:	+49 (761) 4588-5468
Fax:	+49 (761) 4588-9000
Mail:	jochen.doell@ise.fraunhofer.de
Web:	www.ise.fraunhofer.de
_________________________________________________