[BLDG-SIM] Same COP, different chiller, big increase in cooling loads

Steve Mignogna smignogna at gmail.com
Thu Jul 19 12:29:58 PDT 2007


Kevin,

Centrifugal chillers have fewer rubbing parts and usually have a
higher airflow than reciprocating chillers.  As a result, they usually
operate at a higher COP than reciprocating chillers do.  For example,
the minimum ASHRAE (90.1-2004) COP for a reciprocating chiller is 4.2
while for a centrifugal chiller it is in the 5.0 - 6.1 range
(depending on the size of your chiller).  You should try running your
model using the higher COP and see if that helps.

 --
Steve Mignogna
Atelier Ten



On 7/17/07, Kevin Burke <kevin.burke at arup.com> wrote:
>
>
>
>
> Dear All,
>
>
>
> Recently I requested help (and got it, thank you very much) with regard to
> the heating and cooling demand of a 20 sqm zone representing a room in a
> building with one façade fully glazed and a fan coil unit specified. After
> consideration it was concluded that the heating demand calculated with
> eQuest was reasonable however the cooling demand was very very small. The
> chiller chosen was an electric-hermetic-reciprocating chiller (at random
> because I didn't know any better) with an EIR of 0.25 (COP=4.0) and after a
> long time investigating I changed the chiller to a
> electric-hermetic-centrifugal chiller and kept the EIR at 0.25. This
> resulted in the cooling load quadrupling! Does anybody know why this should
> be the case when every other parameter remained the same?
>
>
>
> Kevin Burke
>
>
>
>
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-- 
Steve Mignogna
Atelier Ten

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