# Chiller heater performance curve

I am evaluating the chiller heater system and working with the example file CentralChillerHeaterSystem_Cooling_Heating.idf

Perticularly, I am trying the find out the temperature dependence of performance curves. To evaluate this I created temperature independent curve as below:

```
Curve:Biquadratic,
ChillerHeaterHtgEIRFT_Const, !- Name
1, !- Coefficient1 Constant
0, !- Coefficient2 x
0, !- Coefficient3 x**2
0, !- Coefficient4 y
0, !- Coefficient5 y**2
0, !- Coefficient6 x*y
4.44, !- Minimum Value of x
15.56, !- Maximum Value of x
35.0, !- Minimum Value of y
57.22, !- Maximum Value of y
, !- Minimum Curve Output
, !- Maximum Curve Output
Temperature, !- Input Unit Type for X
Temperature, !- Input Unit Type for Y
Dimensionless; !- Output Unit Type
```

I output the "Chiller Heater EIR Temperature Modifier Multiplier Unit 1" hourly variable and anticipated the output to be a 0 or a 1 at all times. However I am getting fractional values indicating that the output of the above curve is not always 1.

Is this anticipated? I have attached the file with the modified curve.

C:\fakepath\CentralChillerHeaterSystem_Cooling_Heating_CurveTest.idf.jpg