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CBECC MF: Meters in CBECC for Nonresidential vs Residential Enduse #100

Closed joesinger12 closed 2 months ago

joesinger12 commented 2 years ago

Implement addition of meters to segregate non-residential and residential end-uses in CBECC-Com ruleset. This enhancement will enable application of 2022 TDV/Source Energy/Emission Factors appropriately in multi-family/mixed-use projects.

Reported by: joesinger12

Original Ticket: cbecc-com/tickets/3272

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

ES - Attached are the sample files. They separate out the residential, common and nonresidential end-uses for energy use by fuel and compliance using Meter:Custom, Meter:CustomDecrement, Schedule:File and UtilityCost:Tariff.

But, the more atypical part of the solution was the need to change the IDD to accommodate more meters on the Meter:Custom objects. This was done when the request to separate out common areas was requested. When it was just residential versus nonresidential, the Meter:Custom along with Meter:CustomDecrement was sufficient.

Original comment by: joesinger12

joesinger12 commented 2 years ago

DR - Meters approach memo

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joesinger12 commented 2 years ago

RH - T I realized that for central plant equipment we could conceivably have cases where the equipment served res spaces only, nonres spaces only, or any split in between. I agree that a simple rule that will split the central plant energy use between res and nonres is likely to get us 90% of the accuracy of a perfect split for most projects. I also agree that doing a bunch of analysis to demonstrate the effect of different options is not a high priority and can wait until later.

Assuming we have meters that will segregate the central plant energy consumption from the res and nonres energy consumption, we can assign TDV factors to the plant energy by various aspects of the proposed building design. Examples include: • Proportion of total conditioned floor area that is res/nonres. • Proportion of cooling and heating capacity connected to the plant serving res/nonres spaces.

There are probably other options. In any case, this decision can be deferred and analysis is not a priority.

BW - I think we need a very simple rule that will work for the initial draft release of the software. I think Res vs Non-res floor area is a good place to start.

RH - I think that’s fine for now. The advantage of using connected capacity is that it gives us a way to determine plants that serve only res or only nonres. But this can be updated whenever if we have appropriate meters in place.

Original comment by: joesinger12

joesinger12 commented 2 years ago

RH (update to meters memo) : I think what we want is a three meter approach: Res+ResCom, NRes, Central Plant. The first two would get res and nonres TDVs. The central plant energy would be split between res and nonres TDVs based on a rule that is TBD at this point. Options include: Proportion of res/nonres conditioned floor area (including ResCom in Res), proportion of cooling capacity connected to the plant serving res/nonres spaces. If the central plant is heating only, then use heating capacity.

In between that addition and this email, BW sent me an email that, ”I don't want to spend time and resources working this out in detail before we have the software running. I think we need a very simple rule that will work for the initial draft release of the software. I think Res vs Non-res floor area is a good place to start.”

I have no argument with that. Assuming we have the central plant energy consumption on a separate meter, then the rule used to allocate energy can be changed as necessary in the future.

Original comment by: joesinger12

joesinger12 commented 2 years ago

Suggested approaches by RH to CEC:
Option 3 will be revisited when we have working software. In the interim the simple approach suggested above will be used.

One of the issues to be decided in the new MF compliance software is how to segregate energy consumption into separate buckets for the application of residential vs. nonresidential TDV factors.

Energy used in a dwelling unit or a nonresidential space that can be metered separately from the rest of the building will be assigned residential or nonresidential TDVs, as appropriate. On the call today, it was decided that the common areas serving residential spaces such as corridors, lobbies, workout rooms, laundry rooms, etc. would be assigned residential TDV factors.

The problem comes in when there are systems which serve both residential and nonresidential portions of the building. Examples would include: • PV and battery systems
• central hot water boilers providing heat throughout the building • central equipment (boiler, cooling tower, pumps) on a water loop serving water-source heat pumps in both residential and nonresidential spaces

Option 1: In the real world, these systems are likely to have separate utility meters. If the meter is on a residential rate from the utility, it would be appropriate to use residential TDV factors, and nonresidential TDVs if a commercial utility rate is assigned. The assignment of the meter to a residential or commercial tariff, however, will be based on the usage or demand thresholds specific to the utility, meaning that the same building in different locations and climate zones may get different assignment to residential or commercial rates. This variability will make it difficult for the compliance software to have valid rules assigning residential or nonresidential TDVs to the energy used by these systems. In addition, where a large residential building has central systems which are billed on a commercial rate, the cost effectiveness of certain efficiency measures may not align with the analysis used to justify the inclusion of those measures in the standards.

Option 2: Because of the difficulty of identifying when central systems will be billed on a residential vs. a commercial utility rate, central systems can just be assigned to one set of TDV factors or the other on a consistent basis. One extreme of this approach would be to always assign nonresidential TDV factors to central systems. Or, the energy consumption can be split between residential or nonresidential based on a fixed characteristic of the building, such as the proportion of total floor area that is nonresidential vs. residential plus ancillary floor area. This type of approach will provide consistent results and be easy to incorporate into the software. To the extent that nonresidential TDV factors are applied to energy consumption that actually serves residential units, the cost effectiveness concerns mentioned under option 1 may apply.

Option 3: Based on simulation results, energy consumed by the common systems could be allocated based on the fraction of energy consumption used directly by residential or nonresidential spaces. An approach like this should be based on the baseline, because basing it on the proposed design would allow manipulation of the split by the designer and potentially allow gaming. The baseline for a multifamily building will not include central systems serving both residential and nonresidential portions of the building, so the fraction of total energy consumption in the baseline that is residential or nonresidential can be used to establish a fraction that can them be used to split the hourly energy consumption of a central system into residential and nonresidential portions for application of appropriate TDV factors. This approach can work, but is open to criticism that total energy consumption is being used to split an energy stream that may only serve a subset of end uses. For example, allocating gas consumption for a heating hot water boiler based on energy consumption that may be primarily lighting and cooling may be objectionable. It is often the case that heating is a larger fraction of total energy consumption for residences than it is for nonresidential applications, so splitting heating gas or PV electricity on the fraction of total energy consumption may not be completely accurate. This approach does have the virtue of scaling the application of residential vs. nonresidential TDV factors as a function of energy consumption in the building.

Conclusion: My takeaway from the meeting today was that Option 3 was the preferred approach. The fraction of energy consumption in the residential and nonresidential portions of the baseline model would be applied to the energy consumption of common systems in the proposed for application of residential vs. nonresidential TDV factors. However, E3 had in mind a concept involving calculation of a hybrid TDV profile, which may be different from any of the options listed above. This hybrid TDV was not clear to me, so I am not able to evaluate it.

Regardless of the method selected for applying TDV factors to the energy consumption or production of common systems, compliance will be based on the overall total TDV and source energy values for the proposed design compared to the baseline. This means that efficiency tradeoffs between the residential and nonresidential portions of the building will be allowed. Increasing the efficiency of the nonresidential cooling systems could allow the use of less efficient glazing in the residential units.

Original comment by: joesinger12

joesinger12 commented 2 years ago

9/7/21 BW - I proposed that we proceed with the MF Restructuring project without getting diverted initially by the details of the TDV values. The MF Restructuring team has agreed that for shared systems (like PV and central HVAC systems) we can use a simple approach that will let us focus on getting the software done. We think weighting the TDV by the Res vs Com floor area served by the system will be simple and good enough for the 1st release of the MF software. After we get working software we can revisit the decision and study the options with much better tools at that point.

CEC (MS) - I agree with the proposed approach. I think this is a reasonable interim step and we can fine tune it later on, when we have more time. I really don’t think these choices of TDV will have a big impact on measure tradeoffs.

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Creating custom meters was mostly completed in the context of -Com spaces/systems in 2019.2.0 release. However, we will need to revisit these rules and make sure they work with the MF enhancements, and also support using them when modeling Res spaces/systems using E+ in the situations that we do that. For this reason, I'm putting this at 50% since we have not revisited these rules yet in the context of MF tool enhancements.

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joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Changing to Beta when E+ simulation of Res zones is targeted to be supported (if needed). For Alpha4, Res zones will be modeled in CSE, and NonRes in E+, so no need for separate E+ meters

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

Per CEC 3/14 call. Calculate Res/NonRes floor area ratio for each central plant central system. Meter energy use for central plant components (using new meter rules JP added). Ratio energy use of these components accordingly and apply Res or NonRes TDV factors.

Original comment by: joesinger12

joesinger12 commented 2 years ago

Original comment by: joesinger12

joesinger12 commented 2 years ago

A few modification have been committed:

Rename meter names

Area calculation System serving Res/NonRes area are calculated for each component so we can ratio energy use of these components accordingly and apply Res or NonRes TDV factors.

Limitation

Revision: 7138 Author: jireh360 Date: Monday, March 28, 2022 3:30:51 PM Message: Ticket #3272 Meters in CBECC for non-res vs Mfam

Revision: 7144 Author: jireh360 Date: Thursday, March 31, 2022 9:55:24 AM Message: Ticket #3272 Non-res vs Res end-use - Meters

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joesinger12 commented 1 year ago

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joesinger12 commented 1 year ago

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joesinger12 commented 1 year ago

Moving to 2022.2.1 for updates to separate out enduse for nonresidential vs multifamily when shared central systems are modeled.

Limitation to be documented in the Quick Start Guide.

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joesinger12 commented 1 year ago

Original comment by: joesinger12

joesinger12 commented 1 year ago

Original comment by: joesinger12