Merge evaporative pad models

[wehuang16]

@mwetter @JayHuLBL
Hey Michael,

On branch #4489 , I worked on developing evaporative pad models for evaporative coolers in hyperscale data centers. I started with the evaporative pad model from PNNL with an EnergyPlus equation of saturation efficiency, incorporated cubic hermite splines to work with discrete data of the saturation efficiency to this evaporative pad model, incorporated pressure drop parameters using the fan power law, and added additional manufacturers’ evaporative pad data as data records. My work can be found at Buildings.Fluid.Humidifiers.EvaporativePads.

Let me know if my progress in the evaporative pad models can be merged to the branch #3492.

[JayHuLBL]

@wehuang16 I resolved the conflicts by merging the targeting branch issue3492_DirectEvaporativeCooler to your branch. We need to ensure that all the models in the package Buildings.Fluid.Humidifiers.EvaporativePads are ready to review now. For instance, the class Buildings.Fluid.Humidifiers.EvaporativePads.IndirectDry should be refactored.

[wehuang16]

@wehuang16 I resolved the conflicts by merging the targeting branch issue3492_DirectEvaporativeCooler to your branch. We need to ensure that all the models in the package Buildings.Fluid.Humidifiers.EvaporativePads are ready to review now. For instance, the class Buildings.Fluid.Humidifiers.EvaporativePads.IndirectDry should be refactored.

@mwetter @JayHuLBL I have refactored the IndirectDry model in my latest commit to the branch https://github.com/lbl-srg/modelica-buildings/tree/issue4489_coolingTower_directPad. I think it is ready to review now. Let me know what you think!

[wehuang16]

A few questions I still have on the evaporative cooler/pad models:

• The indirect wet model assumes that the leaving air is completely saturated. Is this a fair assumption? I can use modified Poppe equations to explore more on the case where we don’t assume that the leaving air is completely saturated. Should I?
• Why do the indirect wet and indirect dry models assume that the heat exchanger is always air-to-air, and not air-to-water?
• For the model “Buildings.Fluid.Humidifiers.EvaporativePads,” I renamed the description from “direct evaporative cooler” to “direct evaporative pad” to better reflect that this model represents the evaporative pad itself rather than a full cooler machine. However, the model descriptions for the IndirectWet and IndirectDry models are still calling them “coolers.” Should I create a new Modelica directory to separate the “cooler” models from the “pad” models?