[TRNSYS-users] Convergence problem in vapor compression air conditioning system

[David BRADLEY]

Mayank,
   Without seeing your simulation, it is hard to know what is going 
wrong. A few thoughts, though (and I am assuming that you are using 
Type56 to model the building).

1. Make sure that you have adjusted the capacitance of your zones. The 
default capacitance only accounts for the capacitance of the air in the 
zone. Adjust the value to be about 5 times higher than the default in 
each of your zones in TRNBuild.

2. Make sure that you are conditioning the building using temperature 
level control NOT the automatic cooling type that is built into Type56. 
This will involve adding a VENTILATION stream to your building and a 
thermostat model in addition to Type921 and the blower.

3. Make sure that you are using a 1 or a 5 minute time step. TRNSYS can 
only make one control decision each time step. If the time step is too 
long, the zone will get over-cooled long before the end of the time step 
and the controller will try to turn off the air conditioner, which will 
result in the zone getting too hot.

Regards,
  David


On 12/9/2012 12:34, Mayank Bhatnagar wrote:
> Hello All,
>
> I am modeling vapor compression air conditioning system for a house. I 
> am using type 921 with a blower to meet the cooling load of zones of 
> the building. In this I got an error of maximum warning limit exceeds. 
> The warnings are :
> TRNSYS Message    441 : The inputs to the listed units have not 
> converged at this timestep. The values at the last iteration will be 
> used and the simulation will proceed.
>     Reported information  : UNITS: 9  39  64  70
>
> I am not sure, what I am doing wrong.Please help me out.
>
> If some one has example file of this, please share it.
>
> Thank you.
>
> Regards,
>
> Mayank Bhatnagar,
>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at cae.wisc.edu
> https://mailman.cae.wisc.edu/listinfo/trnsys-users

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

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

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