Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Hi, Anna.
The Chiller:Electric:EIR model in EnergyPlus is the same as the DOE2.1 model, which is also available in eQUEST. The form of the model is the same in both cases, but the coefficients would be different for the same chiller because EnergyPlus expects SI units and DOE2/eQUEST expect IP units. The three curves are CAP-FT, EIR-FT and EIR-FPLR.
The Chiller:Electric:ReforumlatedEIR model in EnergyPlus is similar to the eQUEST model that has the added "dT" term, and the goal is to more accurately represent the impact of condenser water temperature reset. But the EnergyPlus model uses a different form compared to the eQUEST model. The main differences are 1) the EnergyPlus model takes condenser water leaving temperature as an input rather than entering temperature, and 2) the EIR-FPLR curve is a function of both PLR and condenser water temperature.
Here's the section in the Engineering Reference: https://bigladdersoftware.com/epx/docs/8-9/engineering-reference/chillers.html#electric-chiller-model-based-on-condenser-leaving-temperature
I believe that it's better to use the reformulated curve if you have the appropriate performance data to be able to create one, especially if you are evaluating the impact of condenser water control. But the other models are pretty good too.
I can't speak to IES-VE curves.
| | 2 | No.2 Revision |
Hi, Anna.
The Chiller:Electric:EIR model in EnergyPlus is the same as the DOE2.1 model, which is also available in eQUEST. The form of the model is the same in both cases, but the coefficients would be different for the same chiller because EnergyPlus expects SI units and DOE2/eQUEST expect IP units. units (there's an EnergyPlus "coeffconv" utility that can help with converting DOE to E+). The three curves are CAP-FT, EIR-FT and EIR-FPLR.
The Chiller:Electric:ReforumlatedEIR model in EnergyPlus is similar to the eQUEST model that has the added "dT" term, and the goal is to more accurately represent the impact of condenser water temperature reset. But the EnergyPlus model uses a different form compared to the eQUEST model. The main differences are 1) the EnergyPlus model takes condenser water leaving temperature as an input rather than entering temperature, and 2) the EIR-FPLR curve is a function of both PLR and condenser water temperature.
Here's the section in the Engineering Reference: https://bigladdersoftware.com/epx/docs/8-9/engineering-reference/chillers.html#electric-chiller-model-based-on-condenser-leaving-temperature
I believe that it's better to use the reformulated curve if you have the appropriate performance data to be able to create one, especially if you are evaluating the impact of condenser water control. But the other models are pretty good too.
I can't speak to IES-VE curves.
