Why Don't I Need a DX Cooling Coil Plant-Side

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Thanks, David. That sounds like a reasonable strategy...the only hesitation that I had about doing just that was that in the building I am modeling this is an evaporator coil and I was afraid CoolingCoil:Water would behave as a CHW coil - without any phase change occurring. Is this not something that I need to worry about?

The plant-side that you described is exactly what I'm looking for.

I believe what the user is asking for is a water-cooled DX cooling coil. So only the condenser water loop would be necessary. Does OS have water-cooled DX coils?

That's correct. Or some kind of work around using an ordinary cooling coil as David suggested and equating the performance to that of a water-cooled DX coil

This answer might be useful.

Ideally, though, it would be a refrigerant (not water) exchanging heat with my air-stream and water loop

The hope was that I could either connect my DX coil to the object in the above image or that there was an evaporator side that corresponded to this object (I can't seem to find one).

The DX 'coils' in EnergyPlus model the whole evaporator+condenser assembly. The Coil:Cooling:WaterToAirHeatPump:EquationFit enables modeling equipment that cools air and rejects heat to a water loop using a curve fit model, thus bypassing the need to characterize the refrigerant and individual subcomponents.

Ah perfect! Thanks...I think I misunderstood your comment on the DOAS thread.

@Eric Ringold It seems that unitary heat pumps cannot be controlled by a supply air set point, but must respond to a set point in a control zone. Is this accurate? If so I'll have to come up with something else.

The AirLoopHVAC:UnitarySystem input field Control Type has an option for 'SetPoint' control. You might also be interested in this question and answer. Although the setup that wraps each coil in a UnitarySystem might require setup using the OpenStudio SDK.

@Eric Ringold It seems that in the question you linked, one is still limited to controlling the unitary system via an individual zone set point. I'm simply trying to control supply air temperature (this unit is supposed to serve all zones on one floor - individual zone set point is achieved via flow through a VAV terminal).

Is what I'm trying to do - control supply air temperature using a DX (or heat pump/unitary) system - really that outlandish?

Also I'm committed because apparently you can't remove unitary systems from an OS model (?)

@jmbattis that question specifies 'Load' control, but that doesn't mean unitary system control is limited to 'Load' (see the other options for the Control Type input). I linked to it because of what it says about wrapping coils in individual unitary systems instead of all in one.

apparently you can't remove unitary systems

Does clicking the 'x' on the icon not work?