Air-To-Water Heat Pump with Heat Recovery

[Nigusse]

Pull request overview

• This new feature adds capability to support heat recovery in air-to-water heat pumps

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[EnergyArchmage]

Here is rough feedback from TRANE...

"Could the setup be expanded to 4 pipe units without any control changes?

Maybe I am mis-interpreting the diagram is this a four-pipe unit (or) a 2-pipe unit with heat recovery?

Our definition of 2 pipe is it can only operate in only one mode (control to a particulate CHW or HW Setpoint). 4 pipes could control to both.

Also, Bob did mention that we do sell heat recovery on four-pipe units but usually it works when its cooling dominant and recovered heat will be to supplement the heating side. To our awareness, the second diagram is not in market yet.

We do agree Brent that we need extra modifier curves to support heat recovery operation, something like below :

I am using VRF example (AIrConditioner:VariableRefrigerantFlow object fields on heat recovery modifier)"

Sounds to me like the model could be setup to handle both 2 pipe or 4 pipe. If there are both of the heating and cooling companion coils for the AWHP, then its a 4 pipe (6 pipes with HR and considering both companions), if no companion heat pump, then it is 2 pipe (4 pipe with HR).

[Nigusse]

@EnergyArchmage Thanks. Please take a look at my response below.

(1) It should be either 2-pipe or 4-pipe ASHP configurations with a heat recovery option. This implies the 2-pipe ASHP with heat recovery becomes a 4-pipe system, and the 4-pipe ASHP with heat recovery becomes a 6-pipe system, assuming the heat recovery generates either HW or CW at a time. The schematic in the initial NFP is just a simple display of the heat recovery concept. I am trying to create a schematic of the equipment and plant layout topology for a 6-pipe system in the EnergyPlus context. It is helpful to see if you have an actual equipment and plant layout configuration of such a system.

(2) It is possible to use different capacity modifier curves when the ASHP operates in heat recovery mode. I must add a new capacity modifier curve input field for cooling and heating modes.

(3) A question regarding the Heat Recovery Ambient Relief Modifier Curve. Is this curve also used to adjust the heat recovery mode capacity? If that is the case, I need to understand how these curves are normalized to implement them correctly.

[nrel-bot-2c]

@Nigusse @Myoldmopar it has been 28 days since this pull request was last updated.

[nrel-bot-3]

@Nigusse @Myoldmopar it has been 28 days since this pull request was last updated.

[Myoldmopar]

Merging this design/NFP only PR. It accompanies #10455 (and #10544 )