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Re: [TRNSYS-users] weird Qcool




Dear Mr. Adrien,

Many thanks for your quick reply!
Did you put a lower ACH for the simulation already? After that, the cooling system works fine? I did. I set the ACH from 2.0 to 0.5 1/h, however, Qcool is still 0, in addition, Tair_room in summer is up to 33/34 °C. It means the cooling system is still not working after reducing the ACH of ventilation system.
So I think it is not reason of ventilation system. I guess there is something wrong with the cooling system in TRNSYS. But I still can't find the solution.
Please give us some suggestions for that! I don't know why there are so many bugs or problems in TRNSYS although it has been a mature BES tool.

Many thanks in advance!

Br.
wang
2012/6/18 Adrien JEZEQUEL - ITF <a.jezequel@itf.biz>
Hi wang,

i check your ventilation system.
  • Airchange of ventilation : 2.75 Vol/h when your building is used
  • Temperature : 17 °C in summer
With 2.75 Vol/h at 17°C in your thermal zone, this is normal that Qcool is equal to 0 since your air is only refreshed by your ventilation system! Your cooling system is not used!
Try to put a lower airflowrate, you will see that cooling system is then used and works fine.

Best regards

www.itf.biz
www.itf.biz
Adrien JEZEQUEL
Simulations Thermiques Dynamiques
ITF
62, Rue du Bolliet
73230 St Alban Leysse
FRANCE
Phone :
Fax :
Mail:
+33(0) 479 750 029
+33(0) 479 852 122
a.jezequel@itf.biz ou aj@itf.biz
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Le 18/06/2012 12:40, 王洋 a écrit :

Dear Mr. Adrien,

Many thanks for your patient and careful answers!

You are right!
Set point for cooling is 26°C in your model. The problem comes from your ventilation system : Temperature of air flow = 17°C in summer. So your ventilation system cools your thermal zone.. Your cooling system is then shunted since Tair < 26°C, that's why you obtain QCool = 0. i advice you to adjust your air flow temperature.
Due to the lower set temperature of ventilation in summer, the Qcool = 0. Since 17 °C is our design standard, so generally it can't be adjusted. In addition, I found there is another Weird phenomenon about Qcool and Tcool. I adjust Tcool based on your suggestion and Equation (Tcool = 35 - 9 * Summer ). I change it into e.g. Tcool = 35 - 8/10/11.../25 * Summer etc., but Tcool doesn't work i.e. Tair_room is keeping the same temperature (please see the 1st attached on line plotter) in all the set point Tcool situatuins (27/25/24.../10 °C), therefore, Qcool is 0 all the time. I checked and adjusted many times for this simulation. It also exists this problem. It made me drive the nuts.

If you are free, please help me have a look the program and give me some solutions or advices. Pleasae see the 2nd and 3rd attached.

Many thanks in advance! I'm very appreciated for all your help!

Br.
wang


2012/6/13 ITF - Adrien JEZEQUEL <a.jezequel@itf.biz>
My answer just here below in your previous message.

best regards

www.itf.biz
www.itf.biz
Adrien JEZEQUEL
Simulations Thermiques Dynamiques
ITF
62, Rue du Bolliet
73230 St Alban Leysse
FRANCE
Phone :
Fax :
Mail:
+33(0) 479 750 029
+33(0) 479 852 122
a.jezequel@itf.biz ou aj@itf.biz
Afin de contribuer au respect de l'environnement, merci de n'imprimer cet e-mail que si nécessaire
Please, consider our environmental responsability before printing this email

Le 13/06/2012 12:58, 王洋 a écrit :
Dear Adrien JEZEQUEL,

Many thanks for your patient reply and checking for my programs.

You are right. The problem is indeed Internal Gains. I define a Schedule based on your advice. After running, it seems better than the previous. However, there are some unreasonable situations. Please see the Attached image.
1. Tair and Top are higher than the set point 21 °C in winter all the time. Tair is closed to 23 °C basically, and it is only 21 °C when no occupancy. I guess the reason is the compensation of internal gains and mechanical ventilation.
In winter your Tair is equal at least at Tset heat (21°C in your model). Temperatures grow up due to solar and internal heat gains, that's why you obtain Tair > 21°C in winter.

Do you have some solutions to make sure that the set point is 21 °C in winter?
check Tair without internal heat gain and solar gain to be sure that your thermal zone is heated at 21°C.


2.Tair and Top are lower than the set point 26 °C in summer all the time. The maximal is only 25.4 °C. I guess the reason is due to the influence of mechanical ventilation, and only a few hot days (Toutdoor>26 °C) in summer.
I would like to ensure that the set point is 26 °C in summer. Do you have some solutions to that problem? Only reduce air change rate of mechanical ventilation? Anything else?
Set point for cooling is 26°C in your model. The problem comes from your ventilation system : Temperature of air flow = 17°C in summer. So your ventilation system cools your thermal zone.. Your cooling system is then shunted since Tair < 26°C, that's why you obtain QCool = 0. i advice you to adjust your air flow temperature.
 
3.Qinf and Qvent are different all over the year although the infiltration rate and ventilation rate settings are the same all over the year. I think Since the weather conditions especially outdoor temperature, wind direction and wind velocity are different all over the year. Am I right?
Yes, you are right. But it's very difficult to take into account accuracy airflows due to infiltration rate, since this is generaly due in one hand to imperfections and in other hand, as you say, to local situation : you have to estimate wind velocity and direction near your building, then, calculate pressure coefficient on each elements of your facade, and then approach your infiltration rate with a law like m' = C.dp.n. You may find some litteratures from Martin Liddament but in first approximation, I advice you to take a constant value equal to 1/20eme airflowrate obtain under 50Pa which seems to be perfect for energy studies.


4. Based on Energy_zone.BAL file, Qcool is 0 all the time. Do you have some ideas? I think it is due to mechanical ventilation and only a few hot days (Toutdoor>26 °C) in summer. Anything else reasons?
See point 2.


Many thanks in advance!

Br.

wang








2012/6/13 ITF - Adrien JEZEQUEL <a.jezequel@itf.biz>
Dear Wang,


You are right : the Tcool I gave you was equal to 26, not to 24°C. Tset value is not important as well, the most important is that you understand how to do to define Tset.
In your model, your heating and cooling advices seem to work fine. Your problem comes frome your internal gain : 31 people are defined all the time in a room of approximatively 80 m², without schedule.
Because of your important internal gains, air temperature increases until 35°C in winter. Then air temperature is refreshed because Tcool = 35°C in winter.
In summer, air is cooled at 24°C, because this is the temperature you define in your cooling advice.


Best regards

www.itf.biz
www.itf.biz
Adrien JEZEQUEL
Simulations Thermiques Dynamiques
ITF
62, Rue du Bolliet
73230 St Alban Leysse
FRANCE
Phone :
Fax :
Mail:
+33(0) 479 750 029
+33(0) 479 852 122
a.jezequel@itf.biz ou aj@itf.biz
Afin de contribuer au respect de l'environnement, merci de n'imprimer cet e-mail que si nécessaire
Please, consider our environmental responsability before printing this email

Le 12/06/2012 18:19, 王洋 a écrit :
Dear Adrien Jezequel,

Thanks for your quick reply!
Tcool = 35 - 9 * Summer means if in summer, Tcool = 26 °C?

I tried
to run the simulation based on your solution Tcool = 35 - 9 * Summer, the result is also like the last Attached.
Oppositely,
it is not my heating system seems to work all the time, it is my cooling system seems to work all the time.
I set internal gains all the year.

Please see the Attached *.tpf and *.bui files, if you have free time , please help me have a look and give me some solutions.

Many thanks in advance!

Br.

wang



2012/6/12 ITF - Adrien JEZEQUEL <a.jezequel@itf.biz>
Or sorry, I made a mistake in my previous mail :
  • Tcool = 35 - 9 * Summer (instead of 35*winter  - 9*summer)
Regarding your heating system it may be something like :
  • Theat = 21*Winter
Regarding your attached picture, your heating system seems to work all the time.
In summer, either you cool at 21°C, either there is no internal gains defined, and you heat at 21°C.
Check your differents inputs.
You can procede step by step (internal gain = 0, ventilation = 0, infiltration rate = 0...) to see the influence of each parameters in your model to catch your issue.

Best regards

www.itf.biz
www.itf.biz
Adrien JEZEQUEL
Simulations Thermiques Dynamiques
ITF
62, Rue du Bolliet
73230 St Alban Leysse
FRANCE
Phone :
Fax :
Mail:
+33(0) 479 750 029
+33(0) 479 852 122
a.jezequel@itf.biz ou aj@itf.biz
Afin de contribuer au respect de l'environnement, merci de n'imprimer cet e-mail que si nécessaire
Please, consider our environmental responsability before printing this email

Le 12/06/2012 17:47, 王洋 a écrit :
Dear Adrien Jezequel,

Many thanks!

I think you'd better put for cooling temperatures

  • 35°C in winter (no cool) - heating temperature at 21°C
  • 24°C in summer
which may be translated in an equation tool by something like :
  • summer = GE(TIME,2162)*LT(TIME,6552)
  • winter = 1 - summer
  • Tcool = 35*Winter - 9*Summer
For Tcool = 35*Winter - 9*Summer, do you mean if in winter, Tcool = 35 °C, so Cooling doesn't work ; if in summer, Tcool = -9°C or 24 °C?

Meanwhile, another weird phenomena appear: After running based on your solution in winter, indoor temperature becomes 35 °C also not 21 °C, although I set heating temperature as 21 °C; in summer, however, indoor temperature becomes 21 °C. Please see the Attached On-Line Plotter image.
Furthermore, when I create another Tcool equation as 35*winter+24*summer, the result is also like the Attached On-Line Plotter image.

Please give me some solutions or advices!
I think the point how to set that Cooling doesn't work in winter? The possible reason of that problem is that I also set a Mechanical Ventilation in winter (Tset=19 °C) and summer
(Tset=17 °C). I guess Maybe the Mechanical Ventilation will influence on Cooling and heating?

Many thanks in advance!

Br.

wang 



2012/6/12 <trnsys-users-request@cae.wisc.edu>
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  1. Re: TRNSYS-users Digest, Vol 90, Issue 23
     (jose.gonzalez@imdea.org)
  2. Re: weird Qcool (ITF - Adrien JEZEQUEL)
  3. Flue gas stack in TRNSYS (Mazen Darwish)
  4. AutoReply: TRNSYS-users Digest, Vol 90, Issue 23
     (kelelo1@kelelo.com)


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From: <jose.gonzalez@imdea.org>
To: trnsys-users@cae.wisc.edu
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Date: Tue, 12 Jun 2012 14:56:21 +0200 (CEST)
Subject: Re: [TRNSYS-users] TRNSYS-users Digest, Vol 90, Issue 23
I am out of the office from Monday, June 11 to Friday, June 15 and unable to respond at this time.

For any urgent matters, please contact Dr. Manuel Romero (manuel.romero_at_imdea.org).

Thank you for your understanding.

Best regards,

José Gonzalez-Aguilar



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From: ITF - Adrien JEZEQUEL <a.jezequel@itf.biz>
To: trnsys-users@cae.wisc.edu
Cc: 
Date: Tue, 12 Jun 2012 15:26:28 +0200
Subject: Re: [TRNSYS-users] weird Qcool
Dear Wang,

As far as I understand, the cooling set temperature you define in your model is :
  • 24°C in summer, which seems to be correct
  • and 0°C in winter... which seems to be wrong, since you don't refresh your thermal zone at 0°C in winter!
That's why you obtain huge cooling loads.
BAL_ENERGY is not 0 because you heat and cool in the same time in winter.

I think you'd better put for cooling temperatures

  • 35°C in winter (no cool) - heating temperature at 21°C
  • 24°C in summer
which may be translated in an equation tool by something like :
  • summer = GE(TIME,2162)*LT(TIME,6552)
  • winter = 1 - summer
  • Tcool = 35*Winter - 9*Summer

Best regards


www.itf.biz
www.itf.biz
Adrien JEZEQUEL
Simulations Thermiques Dynamiques
ITF
62, Rue du Bolliet
73230 St Alban Leysse
FRANCE
Phone :
Fax :
Mail:
+33(0) 479 750 029
+33(0) 479 852 122
a.jezequel@itf.biz ou aj@itf.biz
Afin de contribuer au respect de l'environnement, merci de n'imprimer cet e-mail que si nécessaire
Please, consider our environmental responsability before printing this email

Le 12/06/2012 14:55, 王洋 a écrit :
Dear all,

I make a simulation. The cooling set temperature is 24*Summer schedule (2162 h to 6552 h), The heating set temperature is 21*Winter schedule (the rest hours). After running, however, it appears WEIRD phenomenon. Please see the ATTACHED Energy_zone.BAL file. During the winter period, there are Qcools and Qcool is very large up to 47000 kJ. And then it results in wrong BAL_ENERG, it is not 0.

Please give me some advices and solutions to that!

Many thanks in advance!

Br.

wang 


2012/6/11 <trnsys-users-request@cae.wisc.edu>
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     (kelelo1@kelelo.com)
  3. type666 (Andr?s Montero)
  4. Type 673 heating problem (Santeri Siren)


---------- 已转发邮件 ----------
From: <jose.gonzalez@imdea.org>
To: trnsys-users@cae.wisc.edu
Cc: 
Date: Mon, 11 Jun 2012 16:07:28 +0200 (CEST)
Subject: Re: [TRNSYS-users] TRNSYS-users Digest, Vol 90, Issue 21
I am out of the office from Monday, June 11 to Friday, June 15 and unable to respond at this time.

For any urgent matters, please contact Dr. Manuel Romero (manuel.romero_at_imdea.org).

Thank you for your understanding.

Best regards,

José Gonzalez-Aguilar



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Cc: 
Date: Mon, 11 Jun 2012 14:10:47 GMT
Subject: [TRNSYS-users] AutoReply: TRNSYS-users Digest, Vol 90, Issue 21

I will be out of the office from June 8 - 23 on a backpacking trip with my son and his Venture Crew at Philmont Scout Ranch in New Mexico. I will not have access to email or phone service while I am gone, but I will reply to your message as soon as possible after I return to the office on Monday, June 25th.

Thank you for your patience,
Mark Thornbloom




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To: trnsys-users@cae.wisc.edu
Cc: 
Date: Mon, 11 Jun 2012 16:57:30 +0200
Subject: [TRNSYS-users] type666
Dear Trnsys users,

In order to simulate a water-cooled chiller, first I need to create the 2 external files for this component. 
I'm trying to find some catalogues with information of a 40 to 45 kW water-cooled chiller but the web pages I run into it, ask me to register, but I'm still waiting the username and pasword. Does anyone has a catalgoue with this type of info regarding this cooling capacity machine?

Best regards,

Andrés

--
Andrés Montero I.



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From: Santeri Siren <santeri.siren1@gmail.com>
To: "trnsys käyttäjät" <trnsys-users@cae.wisc.edu>
Cc: 
Date: Mon, 11 Jun 2012 19:56:40 +0300
Subject: [TRNSYS-users] Type 673 heating problem
Dear all,

I cant make type673 heating mode to work. Cooling mode works just fine but when I change the cooling control signal to 0 and heating control signal to 1 it doesnt work anymore. When the heating mode is used nothing happens. Does anyone know why?

Best regards,
Santeri Siren

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Cc: 
Date: Tue, 12 Jun 2012 16:05:51 +0200
Subject: [TRNSYS-users] Flue gas stack in TRNSYS
Hello everyone ,
 
Is there a way to model a flue gas stack in TRNSYS , i need to recirculate hot air and flue gases from the economizer in an HRSG back to a solar tower .
 
i appreciate your ideas.
 
Mazen Darwish
KTH Royal Institute of Technology
Department of Energy Technology
Brinellvägen 68, SE-100 44 Stockholm, Sweden


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Date: Tue, 12 Jun 2012 14:23:03 GMT
Subject: [TRNSYS-users] AutoReply: TRNSYS-users Digest, Vol 90, Issue 23

I will be out of the office from June 8 - 23 on a backpacking trip with my son and his Venture Crew at Philmont Scout Ranch in New Mexico. I will not have access to email or phone service while I am gone, but I will reply to your message as soon as possible after I return to the office on Monday, June 25th.

Thank you for your patience,
Mark Thornbloom



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Attachment: Tcool for lower ach.jpg
Description: JPEG image