Re: [EnergyPlus_Support] the cooling capacity of the chiller (ask again)

[Fred Buhl <wfbuhl@xxxxxxx>]

Lym,

Although the 2 different systems are controlling the buildings to the 
same thermostat
setpoints and the weather is the same, the 2 systems are controlled 
differently and so
perform differently in terms of load the chillers have to meet. The fan 
coil is sized
to meet the zone loads (plus ventilation load if any) while the VAV 
system is sized to meet
the central system load, which depends upon the supply air temperature 
among other
things. For the chillers, you could size one of the cases by hand. You 
should then also
set the loop flow rate by hand.

Fred Buhl

llyymmff wrote:
> Hello, all
> I have a question about the cooling capaity of the chiller for the 
> different air conditioning systems.
> I want to compare the power use of the fan coil system and the VAV
> system, and so I set up the same building, same set point temperature,
> same weather data, same chiller and all the other same conditions for 
> these two systems.
> But why cannot I get the same capacity of the chiller for these two 
> systems? The part load ratio of the chillers are also different at the 
> same time.
> I think that the same building and outdoor/indoor conditions will
> cause the same load, could you please to tell me why the capacity is
> different now?
> I really want someone to help me, Thank you!
>
> Best regards!
> lym
>
>
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