I'm trying to generate a biquadratic curve for a heat pump water heater (HPWH Heating Cap Function Temp). In the EnergyPlus CurveFitTool the INPUT tab asks for Indoor Air Dry-Bulb Temperature and Outdoor Air Dry-Bulb Temperature as the independent variables. Obviously Indoor Air Dry-Bulb Temp doesn't make sense in this case, can I just use the EWT? Or should it be something else?
When I use the values I have all the coefficients are zero, but I'm wondering if it's because I have too many constant values? If anyone has any suggestions I'd really appreciate it. Thanks!
