[TRNSYS-users] Getting COPs greater than the rated in an absorption chiller

[David BRADLEY]

Shahen,
   It is quite normal to get COPs higher than the rated one. The rated 
COP is simply the COP at a particular set of inlet conditions. Those 
inlet conditions are not necessarily the inlet conditions at which the 
machine operates at its most efficient point.
regards
  David


On 9/3/2014 14:54, Shahen Fakhraldin wrote:
> Dear TRNSYS user,
>
> Did anyone face a problem of getting COPs greater than the rated one 
> in a solar assisted absorption system? Where COP rises to around (0.8) 
> at the start of the simulation and gets down to an average (0.75) for 
> the rest of the day, whilst the rated cop is (0.7).
> I assumed the set point temp for the Aux heater 70 C and the 
> timestep was 1min
>
> In my project, a cold tank (type 4) is used to connect between the 
> chiller and the building, with the aid of using type 682 to impose the 
> load.
> Is it resulted from a mistake in the connections of the cold tank?
>
> Down below are the links, where a&b for chiller-tank loop and c&d 
> for tank-load loop
> a- Chilled water temperature and flow rate (chiller107) ---->> 
> Cold-side temperature and flow rate (cold tank)
> b- Temperature (and flow rate) to load (cold tank) --->> Chilled water 
> inlet temp and flow rate (chiller) trough a constant speed pump
> c- Outlet temperature and flow rate (type 682) --->> Hot-side 
> temperature and flow rate (cold tank) through a pump
> d- Temperature (and flow rate) to heat source (cold tank) --->> Inlet 
> temperature and flow rate of type 682
>
> Am I right? If yes, are there other reasons, such as the set point 
> temp of the Aux heater, that might cause this error?
>
> Kind regards,
> Shahen
>
>
>
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-- 
***************************
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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