is_baseline_system_11.2, is_baseline_system_12 Heating and Cooling

[JacksonJ-KC]

https://github.com/pnnl/ruleset-checking-tool/blob/develop/docs/ruleset_functions/baseline_systems/is_baseline_system_11.2.md?plain=1#L35

https://github.com/pnnl/ruleset-checking-tool/blob/develop/docs/ruleset_functions/baseline_systems/is_baseline_system_12.md?plain=1#L37

These baseline system functions are expecting terminal heating and terminal cooling to NOT exist to be considered as System 11 or 12, however this note in the schema indicates that the heating and cooling is supposed to be described at the terminal.

System configurations that typically are at the zone and include a compressor (such as packaged terminal air conditioning, packaged terminal heat pumps, window air conditioning units, and water loop heat pumps) should be reported in the schema using HeatingSystem and CoolingSystem. Systems that include gas or electric furnaces should be reported in the schema using HeatingSystem. System configurations that are at the zone and only include fans and coils (such as four-pipe fan coil, two-pipe fan coil, radiant systems, baseboards, and chilled beams) should be reported in the schema using Terminal with the chilled water and hot water systems described in the cooling_source and heating_source data elements (and any other relevant Terminal Data elements). Evaporative cooling systems should be described in CoolingSystem. Passive diffusers with no coil or fan should be described in Terminal.

[claperle]

Recommend that we clarify the meaning of "At the zone" which was intended to mean non-ducted equipment located inside the zone.

[JacksonJ-KC]

In the case of 4-pipe and 2-pipe fan coils, does the way Heating/Cooling should be described change based on whether it is ducted?

[claperle]

Yes, I think so because if it is ducted then it is no longer a terminal unit. This note is focused on equipment that people tend to think of as terminal equipment.

Christina LaPerle (she/her) PE, BEMP, CPHC®, CEM, CBCP Principal Engineer

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On Thu, Jun 13, 2024 at 2:58 PM Jackson Jarboe @.***> wrote:

In the case of 4-pipe and 2-pipe fan coils, does the way Heating/Cooling should be described change based on whether it is ducted?

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[JacksonJ-KC]

There was a valid concern that is_supply_ducted would not be available because it may not be possible to populate from model inputs, however if we go with Christina's suggested solution "non-ducted, located inside the zone" it seems like the main distinction added for determining if heating/cooling belongs in a HeatingSystem/CoolingSystem vs. in a Terminal - is whether it is ducted.

My suggestion is to clarify the bolded text above by saying:

Single-zone system configurations that only include fans and coils (such as four-pipe fan coil, two-pipe fan coil, radiant systems, baseboards, and chilled beams) should be reported in the schema using Terminal with the chilled water and hot water systems described in the cooling_source and heating_source data elements (and any other relevant Terminal Data elements).

This will provide clear instructions to RPD generation developers and will allow predictable representation of systems that is not dependent on is_supply_ducted. It will also mean revisions to is_baseline_system_11.2, and is_baseline_system_12 to allow/expect terminal heating/cooling

[claperle]

I am not sure about this. The note is meant for equipment that is considered Terminal equipment not all single zone systems. My clarification was to describe the meaning of "terminal equipment" and maybe some terminal equipment can be ducted so there is no useful definition that can be provided? Jackson, have you looked at the other single zone AppG baseline system types to see if changes would need to be made based on your suggested change? Also, how would we distinguish between a ducted and non_ducted system using the approach you describe? I know this is circular logic because we are saying that the reason for this note is because is_supply_ducted may not be able to be populated but then are relying on the population of the coils at the terminal versus system level to be based on whether the equipment is terminal equipment which means that the tool would know whether it was ducted since terminal equipment is not ducted (right?). In other words, how else would a software tool know if the unit is a ducted single zone system like a system 12 or a terminal system like a FCU unless it knew details about the system such as whether it is ducted?

[JacksonJ-KC]

maybe some terminal equipment can be ducted so there is no useful definition that can be provided

This is my feeling.

have you looked at the other single zone AppG baseline system types to see if changes would need to be made based on your suggested change?

Yes, system 11.2 and 12 were the only necessary changes that I noted.

Also, how would we distinguish between a ducted and non_ducted system using the approach you describe?

We have 1 data element currently that depends on knowing if a system is ducted, is_supply_ducted, and we are avoiding using it in the rules wherever possible because we are worried that it might not be possible to populate. If we have the location of the heating and cooling dependent on ducted vs non-ducted (or knowing if it is considered a "terminal unit"), we are adding many more data elements throughout the HeatingSystem, CoolingSystem, and Terminal that will depend on knowing if a system is ducted or considered a terminal unit.

I feel very strongly that the instructions for determining HeatingSystem/CoolingSystem vs. Terminal should be based on number of zones served, the heating and cooling source - any factors that we know can be determined directly from the model, so that a user's input external to the energy model does not affect the structure of data in the RPD.