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A lot is at stake here
EAc1: Optimize Energy Performance is, by far, the most important credit in LEED, based on the number of points available. Up to 10 points are at stake here based on how much you’re able to reduce the project’s predicted energy cost. That large amount of points also reflects the great importance LEED places on reducing energy use and forestalling climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008) 2.The increase in global average temperatures being caused by a buildup of CO2 and other...
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163 Comments
No designed cooling system
90.1 - 2004 Table G3.1 states that "Where no cooling system exists or no cooling system has been specified, the cooling system shall be identical to the system modeled in the baseline building design." Does this mean that if we have System 5 (Packaged DX VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. w/ Reheat) for our baseline, do we have to have another Packaged DX VAV w/ Reheat system in our proposed case for this space? Or can we use a DX fan coil system with a HW coil in our proposed case?
The reason that I am asking is that we have hot water radiant panels serving restrooms in our proposed case (no cooling in the restrooms) and the best way that I can work out with HAP support to model this type of system is a DX fan coil system. It is inaccurate to model the proposed case as a packaged VAV system w/ Reheat because the space will constantly be hit with 55 F air from the VAV system even when it is in heating, causing the energy consumption of the system to be artificially high.
Using the same cooling system in the base case and the proposed design should produce the same energy consumption with no net savings. To eliminate cooling energy consumption altogether for the space that has no cooling system (toilets with radiant heat) set the cooling space temperature high enough so that the cooling equipmentThe equipment used for cooling room air in a building for human comfort. (fans and compressors) does not operate.
James thanks for your reply.
Does anyone have any input about the baseline/proposed system part of the question?
Outdoor air ventilation rates
ASHRAE Standard 90.1-1999 Section 11.4.3(d) requires that the minimum outdoor air ventilation rates are modeled the same between the Proposed and Baseline models. But in our energy models, these rates do not match. Has anyone run into this issue before or have any suggestions for how to address this?
Probably a better place to post this question would be on the appropriate software discuss group found at onebuilding.org.
Using the same ventilation rates in both baseline and design models assures ventilation equality between the two cases. It would be inappropriate to claim energy savings by reducing outdoor air ventilation. However energy recovery that reduces energy consumption to condition outdoor air can be modeled differently in the baseline and proposed designs.
Energy Model
I have an existing builidng but we are renovating exterior walls, roof and adding new interior walls and windows. we are also replacing HVAC system. what is my baseline in this case.
The envelope baseline is the existing condition. See Table G3.1.5 Baseline (f).
The HVAC Baseline is the Appendix G system type, not the existing condition.
Multiple Building Submission
Hello,
I'm working in a project that is a multiple building. Each building has been simulated and we have filled for each one a template. I would like to know how should I submit these templates ( you are just able to submit one template on LEED Online)?
Thanks,
We are thinking to submit the templates on the uploaded documents and leave the template from the credit in blank, with a comment that the templates are on the uploaded documentation.
Does that make sense to you?
Yes. Assuming you are submitting this as one LEED submission you should also add up the results in a separate uploaded document to determine the total % savings for EAc1.
Hello,
I've just received the Review of the project and it seems that they did accept the way that we've submitted this credit, follow bellow:
" It appears that the LEED Submittal Template has not been completed and it is unclear whether the project meets the requirements of this credit. Please provide a revised template that has all applicable sections completed. Provide all supporting documentation as necessary to support the values in the template. Note that although the energy model information may be provided in supplemental output reports, completion of the template is required for compliance."
We've got 5 templates, one for each building, I don't really know how to put the information of each one building in only one template.
Could anyone help me please?
Contact GBCI and explain the situation. You can try calling or go through the contact us on the web site where you can select a review issues and submit a inquiry.
In Reference to Carrier HAP program for energy modeling
HAP 4.5 - We have noticed that there seems to be a glitch and
the read outs indicate that Water source Heat pumps are
providing both heating and cooling at the same time.
Has anyone had this problem and solved the issue??
Suggest contacting Carrier tech support or checking the archives at http://onebuilding.org/
Energy wheel motor being addded to process load
I am using Trace 700 and the energy wheel electric usage for the proposed building is being added to the proposed receptacle load. There is no energy wheel in the baseline design, so my receptacle/process loads are not equal between the two buildings. Will a reviewer accept this if I indicate why the numbers are different?
You should separate the two in the template for LEED. Provide the Equipment Energy Consumption report for both models to support the difference between the Proposed and Baseline models.
Penalize for free cooling?
Hi, I have a single story office building located in Lake Tahoe, California. Our HVAC systems are built-up single zone air handlers with hot water coil. No mechanical cooling will be provided. With the cool summer design temperature at this location, we will be providing 100% outside air.
When modeling the building in EnergyPro, our HVAC systems are being compared to a packaged single zone with DX cooling. Due to the HVAC systems we are using, we are being penalized with "Indoor Fans", "Heat Rejection", and "Pumps & Misc". The baseline model does not have "Heat Rejection" and "Pumps & Misc". EnergyPro is coming up with a cooling load for the building, but since we are not providing any mechanical cooling except for 100% outside air, it looks like we are being penalized for this as well.
For LEED purposes, I'm unable to get a minimum of 14% for the above reasons. Does LEED take exceptions in this case? This is free cooling, but I can't seem to take advantage for LEED. Am I not approaching this correctly? Thanks.
Are you following Title 24 or 90.1?
Marcus - Thanks for the quick response. I'm following Title 24. I have been using EnergyPro to show compliance with Title 24.
Not sure how this works in Title 24 but 90.1 requires modeling a cooling system even if your design does not have one. The work around is to install the system in the models but set the temperatures in both so that it never comes on.
Any Title 24 experts out there?
Energy Modeling for Design Submssion
In my project which is a commercial building at Taipei aiming for LEED NC Gold, the energy modelling is getting delayed. the client wants the Design Submittal to be processed sooner. I understand it is a pre requisite and might be illogical to ask this question. But i would like to know if there is an option of going ahead with the design submittal without the Energy Modelling Results and later submit the same?? i am desperate to find out all possible options to ease our situation!! Kindly let me know if there is any way out.
Any design phase credit can be deferred until the construction phase. For that matter, the entire design phase submission is optional - you can submit everything after construction, if you so choose.
The disadvantage of deferring is that you are building "at risk". If it turns out the design can't meet the pre-req.... well, you've already built it.
You can defer the submission of the energy model until the construction review. In fact it is our preference to do so routinely. Since the model is supposed to reflect what has been built (not what has been designed) we prefer to wait until the end to complete it. When it is submitted with the design credits you are required to sign off at the construction credits phase that nothing changed during construction to affect this credit. In our experience that never happens. Something always changes during construction that affects the model so we always do our final model at the very end (unless our client wants to pay for doing the final model twice).
HAP E20-II and plug loads
Our PME consultant is using HAP software for modeling a 6,000sf lab/research facility. He is trying to get plug loads down to 25%. I am confused as to whether we should simply be using 25% for baseline and new building, or whether the result of a realistic study of plug loads for the new building should then be assigned to the baseline building. Can you refer me/him to an explanation of this?
Always model the building as it has been designed!
(well almost always as there are a couple of minor exceptions here and there)
Do not reduce the plug loads to get to 25%! The best way to model this load is to get an accurate accounting of the actual equipment to be used in the facility and determine the actual energy use (beware of using nameplate data as this tend to overstate the energy use in many cases). Short of that you can use the W/sf levels in the 90.1 User's Manual or in COMNET.
The 25% "default" is very simply a value below which you must explain why the plug loads are below 25%. It is nothing more than that. So do not use 25% as a default.
The value used should be "the result of a realistic study of plug loads for the new building should then be assigned to the baseline building" (well said Jay!).
I'll echo what Marcus said, but strongly suggest you try to measure what the actual plug loads should be. This will not only make your model more accurate but also make sure you don't oversize everything.
Lab planners are notorious for overstating plug loads - you can't just add up the nameplate voltages.
On a recent large university biotech lab building we modeled, the engineers estimated combined lighting and plug loads of 6.2 w/sf. The actual metered data after a year of operation showed a peak electrical hourly demand for the entire building of only 3.8 w/sf - this number includes HVAC, Elevators, etc. (although central plant chilled water, so no chillers)
Occupancy Sensors
A clarify, regarding LEED NC v2.2 - EA credit 1 - Optimize Energy Performance, came to our project team stating the following in one of the topics: "[...] Please verify that credit is not taken where occupancy sensors are required in accordance with Section 9.4.1.2, and indicate where occupancy sensor controls are modeled for credit (if any), verifying that this credit aligns with Table G3.2, and is only applied to fixtures controlled by occupant sensors. [...]". We went for this table (G3.2) and did not understand what the percentages represent. The most part of the spaces of our project are bigger than 5,000 ft2. Can someone help us in what we have to do now?
The percentages in G2 get applied to the lighting power density in the space. So if you have 1.0 W/sf installed in an office with a sensor you enter 0.9 W/sf.
The comment you received is specific to 9.4.1.2. There are spaces listed there that are required to contain occupancy sensors. You need to make sure you do one of the following. 1) model all occupancy sensors in the Proposed and also model occupancy sensors where required in the Baseline; or 2) model only the spaces where occupancy sensors are not required in the Proposed and model no sensors in the Baseline. The preferred method would be #1.
Now it make sense! We had thought this way, but were not so sure that these values could be discounted. And from now on we will make sure that we are following one of the two steps correctly.
Thanks Marcus, your comment is very useful!
Daylighting Controls
There is a question our project team have regarding LEED EA credit 1 - Optimize Energy Performance (for LEED NC v2.2). We used HAP as the energy modeling software, however, in the clarify sent, it has been said that we cannot use it to simulate Daylighting Photocells. We do have daylighting controls included, and we are going to write a narrative describing the controls and how they are implemented in the Proposed energy model. However, They ask us to describe that these controls conform to Table G3.1 Paragraph 6(f). How can we do this? Do we have to prove savings from the use of photocells?
It is my understanding that HAP cannot model daylighting controls. Since the lighting interacts with the HVAC systems (energy-wise) this strategy must be modeled in the modeling software and cannot be calculated outside the software. Basically you cannot claim energy savings associated with daylighting when using HAP except in very limited circumstances. If you are dimming then you cannot claim the savings with HAP.
I am in the same boat as you, Paola. I modeled our building using HAP and I understand there is no way to implement daylighting controls directly through the software. However, is it possible to somehow modify the lighting schedules per zone to reflect a simplified daylighting savings? It would be very very unfortunate to not take credit for this savings.
Unfortunately it is always critical to evaluate the software's capabilities in relation to the potential strategies likely to be in the design. A good modeler knows the limitations of the software they use.
Daylighting is a very complex system to model. The factors which affect the calculation are numerous and there is not a real simple way to estimate it. Even if you could make a schedule change to simulate the energy effects you would need a separate study already done or perform your own to back up the data used to make the schedule change. If you can find something to back up the schedule change you might have a shot but I would think the odds of getting it approved are very slim.
You are correct that HAP cannot directly model daylighting controls but there is a method using SPOT (Sensor Placement and Optimization Tool) that you can use to model your daylighting in SPOT and then use data from the SPOT program to generate a HAP schedule.
We did this recently on a model that we submitted to LEED. Unfortunately we did not describe the process that we used to create the schedules. We got a comment back from the reviewer that seemed contradictory. They said that schedule changes between the proposed and baseline models needed to be submitted using the exceptional calculation method described in Section G2.5. They also said that if HAP can't directly model the controls that we should revise the model to eliminate these controls and submit the projected savings using the exceptional calculations. They went on to say that we should upload a narrative describing the controls, a justification for any schedule changes and any external calculations used to determine the appropriate schedule.
So my question is, can we keep the schedules that have been exported from SPOT in our Proposed case HAP model and just upload a narrative and a justification for the schedule changes? Or do we need to apply the same schedules to proposed and baseline cases and do some sort of hand calc? It would seem silly to me to remove the schedules from HAP because it is the most accurate way of modeling the controls and it is based on the external modeling data from SPOT.
Please let me know what you think!
Submit as an exceptional calculation. The comments are not contradictory. In your base models the schedules must be identical. For your exceptional calculation you will be varying the schedule.
So question #1 - no
#2 - do not do any hand calcs the calcs must be in the modeling software since the lighting significantly affects other energy end uses like heating and cooling.
So in your proosed model remove the schedules and make sure that the schedules are identical in the proposed and baseline. When doing the exceptional calculation add back in the schedule change to your proposed model and provide a thorough explanation including the SPOT calculations and results to justify the schedule change.
Ok, that does make sense. Thanks again Marcus!
New building additions and major renovation to existing
We are building two new wings (additions) onto and existing building that will retain its envelope but undergo major systems replacement. The entire complex will be served from a central heating/cooling plant in one of the new building wings. In order to demonstrate 10% improvement for new buidings and 5% improvement for major renovation to the existing building, do we need to create two building models (1 new and 1 major renovation) each having its own virtual plant and post processing the results?
please define your LEED scope of work- is it the 2 new wings being added AND the renovation of the existing main core building- so all work being done?
if they are all one building when done then the savings requirement will be a weighted average of the square footage of new and existing components. For example if 50% new and 50% existing the threshold becomes 7.5% for the entire project. If not one contiguous building then see Debra's question above.
Yes, the complex will be considered one building. From a modeling perspective, I presume I need two energy models, each with their own downsized virtual plant in order to account for the central plant's contribution to the energy consumption/cost of the new buildings as well as the existing building.
If the new and existing will share a central plant then no need to model them separately at all. If the plant serves anything outside your LEED project you could proportion the load and create a virtual plant.
Unless it comes under the DES, then follow those guidelines.
lebanon energy rates
hi,
i m working in project in beirut lebanon.can i use energy rates provided by eletrical authority or i need another source?.
regards,
Use the local rates.
ID credit for Peak Demand Reduction NOT demand response
HI Everyone,
I am working on a LEED-NC v2.2 project which is small but has three technologies that reduce peak demand which is critical here in Connecticut.
My question is how to calculate that % reduction in peak demand to go for an Innovation-In-Design credit for Peak DEmand Reduction NOT demand response as seen in Pilot Credit 8.
I feel that the Calculation should be as follows:
Calculations:
We will calculate the average hourly electricity demand reduction for each energy system (PV, Solatubes, mchp) by month to get a Total average hourly electricity demand reduction by month, TAHEDR per month. This electrical demand reduction will then be compared to the Total avg. hourly Electric use per month, TAHEU per Month that the energy model indicates the Budget Building would be using to get a percent savings in electrical demand over the budget case.
The Total annual demand savings is the Sum of this ratio below done for each month x100%
Design TAHEDR per Month
_____________________
Budget TAHEU per Month
Anyone feel otherwise or agree?
please let me know.
Thank you very much!
Debra Lombard, LEED AP, EMIT, EIT
Debra, sorry for the slow response to your post. Since it's about an IDc1 question, could you please post it to our IDc1 forum? Thanks!
There are several ways you could slice this depending upon what you what to know. How it is calculated is probably less important in LEED than what is the environmental benefit and is it captured elsewhere in LEED.
To claim an ID credit for demand reduction however you will need to show an environmental benefit beyond the energy savings under EAc1. If you use an average $/kWhA kilowatt-hour is a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour. One kWh is equivalent to 3,412 Btu. to calculate your savings then the demand savings is not necessarily fully captured. If you use the actual tariff then the demand savings would be fully counted. Either way the demand savings are at least partially credited in EAc1 so I would guess that an ID credit is unlikely since the environmental benefit is already covered in EAc1.
The potnetial benefit here is also a complicated issue. Shaving peak is aggregate allows for fewer generation facilities. In many areas however the peak natural gas plants pollute less than the baseload coal plants and have fewer issues than the baseload nukes.
HVAC and Lighting Systems for Phase Building
I am working on an energy model for a building that due to budget concerns has now changed to being built in 6 different phases. The decision was made to certify phases 1-4. Before the job was changed to being phased, a full design was completed (95% CDs). Now there are architectural drawings showing all four phases, but the HVAC and electrical drawings only show the first two phases. Is it ok to revise the model based on a combination of the new phased plans and the older 95% CD plans or do I need to treat the portions of the building under phases 3 and 4 as if there has been no design yet for the HVAC and lighting? The system type, GSHP, isnt changing from the previous design to now. The only changes appear to be in system size and light fixture type. Thanks for any guidance!
We did a similar thing to a medical dental center at Ft. Campbell. It was a 2 phase project and we merely added the second phase to the origianl energy model and provided each set of A/E cd's to support our claims. GBCI didnt have any comlaints about the one energy model and phased drawings.
EA Credit 1 load information question
If a building's air handling units were selected (and installed) larger than what is required, as determined by recent cooling load information, may the actual (brake) horse power requirements be input into the LEED spread sheets in lieu of the originally scheduled, but incorrect, values. Note, in these cases, variable speed drives are used with the air handlers and therefore, airflow and horsepower use will reflect actual (correct) conditions, not the originally expected (incorrect) conditions. An updated air handler schedule will be provided as part of the official LEED response.
All projects are supposed to model what was installed in the finished building, not what was designed.
Even if you submit the emergy model in a design review you are then required to check off that nothing changed during construction that would affect the modeling results. This is why we always wait until the construction submission to complete the final energy model.
Energy Modeling in building's using both new and existing HVAC
Our design team is working on a project where we are building an addition and performing some remodeling inside an existing medical clinic. teh remodelled area is being fed off the exisitng HVAC sysytems that serves the original building. There are no plans to retrofit the existing system and we are only modeling the addition and its system. We are counting the remodelled space in our IEQ and MR credits as part of the whole project. Question remains... Do we need to bring the remodelled are into our energy model and count the existing, and much less efficient HVAC system?
THe LEED project boundary must be consistent across all LEED credits.
Service Water - Baseline vs. Proposed
Can I take a credit for the service water in my proposed building versus the Table 7.8 minimum requirements in ASHRAE? If so, is there a calculation to figure that? I have (6) 199 mbh gas fired instantaneous water heaters (storage capacity virtually 0, but we can say 0.6 gallons for calc from the coil). This means I have an EF requirement of 0.619 EF for my baseline, but my (6) proposed units are rated at 0.93 EF, can I do that? And if so, is there a calculation to figure the MBH difference?
Yep, assuming your figures are correct you can claim savings from the efficiency differential. Typically the modeling software we use does the calcualtions. If the modeling software you use can't the calculations outside the software for this end use would be needed.
Check the internet for calculators. I know I have seen them but can't point you to it right now. Also check the ASHRAE HVAC Applications Handbook which has a chapter on service hot water.
Unconditioned Factory Building
At an unconditioned factory building in Bogota (Colombia), we have the question if an energy model would be really necessary, because the energy saving will be only from the installed lighting.
If the energy model would be neceassary then the question is if according ASHRAE 90.1-2007 Appendix G table G3.1 No.10 HVAC Systems point c/d has to be modeled - Where no heating/cooling system exists or no heating/cooling system has been specified the heating/cooling system shall be identical to the system modeled in the baseline building design - or if in both (baseline and proposed) there will be no HVAC system modeled?
The energy model is necessary. In addtion to lighting I would assume you have hot water, ventialtion and process loads, all of which consume energy.
Under LEED v2.2 the Standard is 90.1-2004 but the table citation you mention is the same. Table G3.10(c/d) say that you must model the heating and cooling systems identically. G3.1.1 requires you to model the baseline heating and cooling system.
Baseline System for G3.1.1 Exception (c) dominated project
The subject project is a hospital and outpatient clinic in Climate ZoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 3A. The building is approximately 500,000 sf, seven floors, heated with a hot water fossil fuel boiler. About 400,000 sf of that area (80% of the total) is clinical space characterized by zones having special pressurization relationships, cross-contamination requirements, or code required minimum circulation rates (let’s call these “Exception (c) spaces”). The remaining area (approximately 100,000 sf) is public circulation and administration space with no Exception (c)-like requirements.
In accordance with ASHRAE Standard 90.1, Appendix G, Paragraph G3.1.1, we enter Table G3.1.1A to select a baseline system based on usage, number of floors, conditioned floor area, and heating source. Since our building is nonresidential and greater than 150,000 sf in conditioned area, heated by a hot water fossil fuel boiler, we select System 7 (VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. with reheat) as our baseline system.
However, since we have zones that are Exception (c) spaces, we apply G3.1.1 Exception (c) for those zones, and use System 3 (PSZ-AC) systems to serve those zones.
Since the predominant condition of the building is Exception (c) spaces, we think the baseline system type for this entire building is System 3. Refer to the footnote to Table G3.1.1: “Where attributes make a building eligible for more than one baseline system type, use the predominant condition to determine the system type for the entire building”.
Are we correct in selecting System 3 as the baseline system for the whole building?
Your approach is consistent with the Standard. The only reason to use more than one system is covered by exception (a) where the non-predominant condition specifically involves residential/non-residential or different heating sources for areas exceeding 20,000 square feet of conditioned floor area. Your building does not meet this test. System Type 3 PSZ-AC is the correct choice.
In my opinion the exceptions under G3.1.1 all allow for a second baseline system. G3.1.1(c) clearly states that you apply system 3 or 4 to any "zones" meeting the criteria. It does not state that you use system 3 for the entire building.
The note under table specifically refers to the baseline system selection in the table, not to make an exception apply to the whole building. This note is there to address issues like gas vs electric, residential vs non, etc.
The exceptions are optionally applied so I would expect to see either a combination of systems 3 and 7 or all system 7.
District Thermal Energy Step One pumping question
I am aware of the new v2.0 LEED directive for District Thermal Energy, but I submitted the model in questions months ago for a LEED v2.2 project and was looking for help specific to v1.0 guidelines. But I think my specific issue is identical in both v1.0 and v2.0 guidance documents anyways.
The issue is pump related:
To keep the upstream equipmentUpstream equipment consists of all heating or cooling systems, equipment, and controls that are associated with a district energy system but are not part of the project building's thermal connection or do not interface with the district energy system. It includes the central energy plant and all transmission and distribution equipment associated with transporting the thermal energy to the project building and site. identical, I did not model any pumps for the chiller or purchased steam (obviously). But I did model the secondary pumps as App G 3.1.3.5 (hot water pumps) and 3.1.3.10 (chilled water pumps) defines. My building was 75,000 s.f. so heating was 19 W/gpm continuous variable flow and chilled water pumps were 22 W/gpm riding the pump curve. My interpretation was that because we are supposed to model downstream devices, building distribution pumps should be modeled as stated in the Terminology section of guidance document.
My proposed design are pumps with VFDA variable frequency drive (VFD) is a device for for controlling the speed of a motor by controlling the frequency of the electrical power supplied to it. VFDs may be used to improve the efficiency of mechanical systems as well as comfort, because they use only as much power as needed, and can be adjusted continuously.'s, so obviously there are decent savings for pumping in my model.
The LEED review comments summarized were: You cannot have any differences in pumping for Baseline and proposed because this is DES.
Anyone have opinions?
Hi Jeremy,
I have an identical dilemma in terms of a DES energy supplied building that has distribution pumps in the building. Can't find a good answer to your questions.
Please let me know if you found the way out. Thank you,
Marina
Low Process Energy in Residential for LEEDv2.2-NC
My project is a high-rise condo project in Dallas, TX. In the final analysis, our Baseline process energy costs are coming short at about 12% of the total energy costs. I am inclined to simply state in the EA credit 1 narrative "it's a residential project, yeah, it's got low receptacle loads" but I'm not sure how the reviewer would receive that. I don't find any default receptacle W/SF in the LEEDv2.2-NC reference guide or the ASHRAE 90.1-2004 user's manual. Any suggestions for resources or verbiage to reliably satisfy the EA TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system.? Thanks!
Simply provide a narrative describing what was modeled. Including a spreadsheet of the assumed process loads is usually all you need.
Supply and Return Fan Power - Baseline System
ASHRAE 90.1 App. G 3.1.2.9 specifies the definition supply fan power in the baseline building. The result is calculated to be approx. 1.1 W/CFM.
What about the fan power of the return fan ?
a) is it nearly the same - 1.1 W/CFM ?
b) Is it included in the calculated supply fan power of 1.1 W/CFM?
Let's say Supply Fan=0.6 W/CFM and Return Fan=0.5 W/CFM?
c) Is there a credit for Heat Recovery ?
Regards Heinrich
The fan power calculation under G3.1.2.9 should include the return fan. So b) is correct.
If you follow addendum ac there is a credit for heat recovery. You can only apply this credit in the baseline if energy recovery is required in the baseline according to G3.1.2.10.
Definition of basement partition walls in Baseline Building
We are wondering about definition of basement partition walls for the baseline building according to LEED NC-V2.2 and LEED CS 2.0. For the definition of basement walls the tables 5.5.1-5.5-8 ASHRAE 90.1-2004 specify below grade walls only. This walls are carried out without insulation (C=1.14, NR) for heated and for semiheated rooms.
So what about definition for the baseline building when most of the basement walls of the proposed building are insulated because most basement rooms are heated and ventilated.
Should we use identical constructions for partition walls of baseline and proposed building because this walls are not mentioned in the tables?
Or can we use no insulation for the partition walls because below grade walls are not specified insulated?
Regards Heinrich
The below grade walls in Tables 5.5.1 - 5.5.8 apply to the exterior walls only. So the baseline is uninsulated walls and the proposed is as designed. If it is a partition wall anywhere in the building and it is heated on both sides then there is no insulation needed or required. So yes model them identically in both models.
Marcus,
what about the basement semiheated walls to the unheated garage. Should they be insulated as they are in the proposed?
If yes, basement walls of baseline would be unisolated to the exterior and insulated to unheated space - curious !
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