Unmet Hours

Heat recovery Chiller - Central Heat Pump System

asked 2018-05-23 14:44:30 -0600

updated 2018-05-24 09:46:54 -0600

I'm trying to incorporate a heat recovery chiller between my condensing loop and my heating loop instead of doing free cooling with economizer control. I'm using Openstudio version 2.5.1, and have followed the Central Heat Pump System object has proposed by @Julien_Marrec in this fix.

I think this method is pretty new, I did not find example to guide me in the assembly of this measure and the control that is adequate.

This is how I placed the Central heat pump system object in my three loops: Cooling/condensing loop

The best scenario would be to have the boiler and the heat pump in parallel and to control the exist temperature of the heat pump. Also, how to be able to prioritize the use of the heat pump when there is cooling ?

Heating loop

It would be appreciated to have a file or screen shots of the proper assembly, with the nodes entry if required. Also, and example of control that could be used would be great.

Thanks !

answered 2018-05-24 10:23:50 -0600

Julien Marrec

29706 ●94 ●76 http://www.effibem.com/

I don't have the bandwith to create screenshots etc, but I can give you a few pointers.

For the HW Loop, you want to set the control scheme to "SequentialLoad" and you want to build a PlantEquipmentOperation:HeatingLoad and place the heatpump first in line before the boiler, so it end ups working first with the boiler as backup.

Same for the ChW Loop, except you'd use a PlantEquipmentOperation:CoolingLoad.

Theoretically speaking, if you don't want to use the API (ruby) to create an explicit PlantEquipmentOperation Scheme, if you ensure you place the ChillerHeater first on the supply side of the loop and then the boiler, it should do the right thing. Make sure you look at the in.idf that is generated to ensure that is the case.

Note that there is currently a bug in this object, you'll have to hardsize the ChillerPerformance:Electric:EIR Reference Cooling Mode Evaporator Capacity, see issue#6445 for more info.

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@Julien Marrec what if I have four boilers as backup for the heat recovery chiller, and I want to modulate them based on their optimal operation? so I want the heat recovery chiller to work first at maximum capacity it can and then 4 boilers to modulate in their optimum PLR.