Add water heaters to supply side of different loops

[lymereJ]

Enhancement Request

Support adding a water heater to the supply side of different plant loops.

Detailed Description

In EnergyPlus, water heaters can be connected to the supply side of two different plant loops through the source/use side connections. It is currently not possible to do so in OpenStudio. One example of this configuration is heat recovery chiller through a ChillerElectricEIR object.

[tijcolem]

@jmarrec I think this would affect the OS app. Do you have any thoughts on this?

[jmarrec]

Doesn't matter if it affects the OSApp or not, not the problem of the SDK (but yes, it's manageable on the App side).

I'm more worried about changing the way things are in terms of API. It might be confusing for users to have addToNode suddenly behave differently. Here is the way things work right now

m = Model.new
wh = WaterHeaterMixed.new(m)
p1 = PlantLoop.new(m)
p2 = PlantLoop.new(m)

wh.addToNode(p1.supplyInletNode)
raise if wh.plantLoop.empty?
raise if !wh.secondaryPlantLoop.empty?
raise if wh.plantLoop.get != p1
raise if p1.supplyComponents("OS:WaterHeater:Mixed".to_IddObjectType).size() != 1
raise if p2.supplyComponents("OS:WaterHeater:Mixed".to_IddObjectType).size() != 0

# Connect to another node on the supply side? It disconnects from the first plant loop and reconnects to another
wh.addToNode(p2.supplyInletNode)
raise if wh.plantLoop.empty?
raise if !wh.secondaryPlantLoop.empty?
raise if wh.plantLoop.get != p2
raise if p1.supplyComponents("OS:WaterHeater:Mixed".to_IddObjectType).size() != 0
raise if p2.supplyComponents("OS:WaterHeater:Mixed".to_IddObjectType).size() != 1

How do you deal with letting users connect to both sides without breaking the way addToNode / PlantLoop::addSupplyBranchForComponent worked historically?

The only sensible thing I can think of is to let those untouched completely, but add a new WaterHeater::addToSecondaryNode method that would let you do that and that the user will need to manually call. That will require the user to potentially do some workarounds to first add a branch onto the supply side of the plant loop, with a bypass pipe for eg, get the inlet node of that pipe, WeatherHeaterMixed::addToSecondaryNode to it, then remove pipe.

@kbenne thoughts please?

[mdahlhausen]

@tijcolem @jmarrec bumping this enhancement request. Heat recovery chiller functionality is the top ask from Ladybug Tools for openstudio-standards.

[joseph-robertson]

@mdahlhausen Do you know of an idf test file with this configuration?

[lymereJ]

@joseph-robertson - The hospital prototype building models for 90.1-2019 should have it: https://www.energycodes.gov/prototype-building-models. Or, this file.