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Re: [EnergyPlus_Support] Water-side economizer



1.  Const COP chiller is an ideal chiller.  Use CHILLER:ELECTRIC or 
CHILLER:ELECTRIC:EIR

2.  The CHILLER:ELECTRIC and CHILLER:ELECTRIC:EIR models automatically adjust 
for differening chilled water and condenser water temperatures.  The design (or 
nominal) COP entered for the chiller must be consistent with the design chilled 
water and design entering condenser temperatures.  You can report the chiller 
COP using REPORT VARIABLE "Chiller COP".

Mike


On 22 Oct 2006 at 23:48, Zhen Tian wrote:

> Dear all,
>    
>   I am trying to utilize the water-side economizer within EnergyPlus by adding
> a Free Cooler Branch: HEAT EXCHANGER:HYDRONIC:FREE COOLING.
>    
>   By referred to the example file: Free cooling chiller.idf, I have some
> questions not fully understand. I looked up the manual, but got no answer.
>   The following are my questions:
>    
>   1. What is the difference between Chiller: Electric and Chiller: Const
> COP?
>       In the real application, which one is more practical? To me, the Const
> COP chiller is a new thing and I havent heard it before.
>    
>   2. When I use the object of Chiller: Electric, I am not quite sure about
> some of the parameters. For example, when the chiller supply water is 6 degree
> C and the COP is 3.2, but if I increase chiller water temperature to 15 degree
> C (used for radiant cooling), should I change the COP to about 4.3 in the
> model input? Also, should I change the Coefficients inputs? If I have to
> change these coefficient inputs, where can I get some reference data?
>    
>   3. I am confusing about the working consequency of the chiller and HEAT
> EXCHANGER:HYDRONIC:FREE COOLING. What is mechnism of how it works? What is the
> control logic for these two parts? In the Free cooling chiller.idf, I noticed
> that the free cooling schedule is set as 8 degree C and the chiller supply
> water temperature schedule is set as 10 degree C. What is the control logic
> between these two temperatures.
>    
>   Could somebody give me some explanations about these questions? 
>   I really appreciate your help.
>    
>   Best Regards,
>    
>   Zhen Tian
> 
>  		
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========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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