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# How to set chillers operating alternately?

Hi everyone, I am simulating a building with two electric chillers which are same type( same capacity, energy consumption) in EnergyPlus. In reality two chillers are operating alternately(when "Chiller01" is operating, "Chiller02" turns off), how should I set operate strategy in EnergyPlus? Is it only I set 365 days operate strategies to simulate? Or I should only set a single chiller in EnergyPlus.

If there is any response, then I would be very grateful.

Sincerely, Yueh-Chin

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Please explain why you need two chillers if you want only one to operate at a time.

Usually, you would need two chillers to meet your design day demands; the demand shared between the two adding up to the total. During lower demand hours, you can set the operation control under 'Plant-condenser control' in you order preference. example:- once you have the equipment list as CoolSys1 Chiller1 supply and CoolSys1 Chiller 2supply,

IDF,PlantEquipmentOperation:CoolingLoad,CoolSys1 Operation Scheme,0.0,50000,CoolSys1 Chiller1 supply,50000,10000000,CoolSys1 Chiller 2supply,,,,,,,,,,,,,,,,,,,,,,,,;


If you still want to limit operation, have you tried using Schedules for each chiller instead of always ON to alternate hours. This will be very crude way, but you can try.

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In my case, the system designer set one of two chillers as a spare chiller. To avoid chiller without long-term operation lead to failure, the designer make chiller operate alternately("Chiller01" turns on & "Chiller02" turns off at day1, then "Chiller02" turns on & "Chiller01" turns off at day2), it also helps chillers operating at high load and high efficiency.

( 2016-06-04 23:14:59 -0500 )edit

If they are never operating together then just model a single chiller that will be enough for your need. Aggregate your data based on the days of operation from both chiller as post processing.

( 2016-10-17 15:06:56 -0500 )edit