Performance Curves for HeatExchanger:AirToAir:SensibleAndLatent

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I have questions about performance curves for HeatExchanger:AirToAir:SensibleAndLatent.

4 performance curves are available in EnergyPlus V24-1-0 and later versions to determine the values of sensible/latent effectiveness for heating/cooling, but Input/Output Reference explains very little about the curves.

1. What is the function of the curves?

   The code suggests that the performance curves are a function of HXAirVolFlowRatio = Ratio of average actual air volume flow through HX to nominal HX air volume flow = (Actual supply air volume flow rate + Actual exhaust air volume flow rate) / 2 / Nominal supply air volume flow rate), but I'm not sure.

2. What types of Curve/Table are allowed?

   I checked some ExampleFiles. All of them use Table:Lookup. What about Curve:Quadratic, Curve:Cubic or Curve:Quartic?

A lot of discussion is in this request, and it is recognised that the HX effectiveness depends on many variables e.g. supply/exhaust air flow rate, temperature and humidity, but the final deliverables still appears to have limitid modelling capability. I haven't tested, but EMS could set up the 4 performance curves as EMS Actuators and override the curve results to take the above variables into account.