[TRNSYS-users] Radiator modeling- Type 1231

[David BRADLEY]

Pouyan,

  The method I usually use when sizing equipment (radiators or 
otherwise) is to set each room of the building up with a set point 
temperature and an automatic heating type in TRNBuild. I then find the 
max hourly heating required from among the Type56 outputs and then size 
each piece of equipment accordingly. It sounds as though your method is 
the same.

  10C sounds correct for a design air temperature but keep in mind that 
the radiator's capacity can be quite different if you are asking it to 
maintain an air temperature that is significantly different than the 
design air temperature. You may run into trouble if you set the design 
air temperature to 10C but are in fact trying to maintain 20C in the room.

  I unfortunately don't have any experience regarding setting the number 
of channels. However, I would encourage you to play around with the 
value. Make your best guess and run a simulation. Increase the number by 
20% and run again. Decrease it by 20% and run it again. Look at the 
results each time and determine whether those results are sensitive to 
the value in question. If they are then you can dig in and try and get a 
more accurate value; perhaps by talking to manufacturers. If they aren't 
then you can proceed using your best guess value.

kind regards,

  David


On 07/14/2021 08:15, Pouyan Talebizadehsardari (Staff) via TRNSYS-users 
wrote:
>
> Dear All,
>
> I hope all are well. I’d really appreciate it if anyone can help me 
> with the following questions:
>
> I am using a radiator (Type 1231) for each room to warm up a building 
> (Type 56). First, I determined the maximum loss for this building by 
> choosing a heating setpoint. Then, I chose the maximum heat loss for 
> each room as the design capacity of the radiator. Does anyone know if 
> I do it correct?
>
> I chose 55C for the design surface temperature of the radiator. My 
> boiler works at the temperature of 60C. What about the design air 
> temperature? As I know, these values are selected based on the 
> manufacturer and it is usually 50C less than the mean temperature of 
> the radiator. So, I consider it the predefined value of 10C.  Am I 
> correct?
>
> Also, for the number of pipes,  as I understand, it is related to 
> correct the heat transfer to the room and a higher number of pipes 
> results in a lower heat transferred to the room. Does anyone know if 
> it is exactly equal to the number of water channels insider the 
> radiator? If yes, so, It should be related to the length of the 
> radiator and so a higher number should be selected for a radiator with 
> a higher capacity.
>
> Thanks in advance
>
> Kind regards
>
> Pouyan
>
> *********************************************************************************
>
> *Pouyan Talebizadeh Sardari*, BSc MSc PhD AFHEA
>
> Centre for Sustainable Energy Use in Food Chains,
>
> Institute of Energy Futures,
>
> Brunel University London,
>
> Kingston Lane, Uxbridge, Middlesex, UB8 3PH, UK
>
> Email: pouyan.talebizadehsardari at brunel.ac.uk 
> <mailto:pouyan.talebizadehsardari at brunel.ac.uk>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

P:+1.608.274.2577
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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