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116 Comments
tenant work: fan coils
Hello all, I'm working on a C&S project. The whole building is already leased to one client, who wants to use one half as laboratories and the other as offices.
For the ventilation of the laboratories a 100% OA-system is part of the C&S-development, with the ducts ending right in the shaft.
The office spaces are ventilated naturally.
Chillers are installed on the roof (as part of C&S) and cw-pipes are installed, ending right in the shaft, too.
These can be connected to fancoils, working only with recirculation air, but this is part of the tenants work (and most likely to be done as we are planning with cooling loads > 100 W/m² in the laboratories). There are no agreements with the tenant facing this.
The Baseline is simulated with System 5.
In my understanding, equipment, that is not part of C&S should be modeled the same in Proposed and BL.
But having a 100% OA system on the one hand and System 5 on the other, I really don't know how this equipment should be modeled.
I thought of adding Fancoils in both systems, sized equally, that make up the recirculation air. But then I fear frictions in the autosizing of the Baseline.
Would be glad to get your opinions.
Equipment not part of the CS can be included if it has already been designed or installed. You would only need to model the Proposed and Baseline identical if there is no tenant space design/installation. If you have a completed tenant space design you can model it as designed/installed and claim credit for any savings.
Several of the addenda that became a part of ASHRAE 90.1-2007 were specific to accounting for lab spaces so a fair comparison can be made.
Carpark and definition of GFA
Dear Sir/Madam
We are certifying a large retail mall which have a large carpark block ( five levels). Some energy efficiency measures is present in the carpark block such as daylight sensors
However the MPR states that carparks are not included in LEED definition of GFA
However when we undertake the energy simulation, we have to include the carpark as part of GFA in order to run the simulation and to include the savings
Please advise. Thank you
No problem follow the MPR guidance for the building square footage and make sure you explain the difference in your EAp2 submission.
Tenant leases, credit for upgrades other than LPD reduction?
Has anyone been successful in claiming savings in tenant spaces for anything other then lighting power reductions? Demand controlled ventilation, daylight sensors or plug load reductions perhaps? As long as they are included in the tenant lease agreement?
Thanks!
Energy Model
Hi, I am about to start to model a Building which includes a Ventilated Facade. But I don't have any idea how to represent it on the simulation program. The program I know is Design Builder (energy +), but I don't have any idea how to represent it. And the othe question is if I hafe to model the complete concrete and iron structure, or just the spaces. We are trying to achieve an LEED CS 2.0 certification. We have an Commercial area and General Office.
Do we have to model tenant spaces? Assuming what they could have, am I right?
I'm new in this and I would like to have a little help on this, please! Because I have to do the hole Simulation by myself!
Thanks
Interestingly enough we just finished an Energy Plus model with a double facade. This is a bit too involved to explain in a LEED forum. I'd suggest checking in with the Design Builder folks or the Energy Plus help desk on how to do the modeling. Typically you build spaces in a model and them assign characteristics, including mass, to the elements of those spaces.
As far as a CS project is concerned - yes you will need to model all the energy use associated with the whole building including the tenant spaces.
modelling of tenant areas in a core and shell LEED project
Dear All, My question refers to the LEED Core and Shell modelling guidelines in Appendix 2 of the LEED BD&C guide.
Under the subheading 'tenant spaces' it states that ...'... if the team is pursuing any additional energy saving opportunities not associated with core and shell areas..... outline opportunities....' and then it goes on '... model the electric meters....'
WHat if we are not pursuing any additional saving from the tenant areas...
do we need to model the tenant areas individually
I am modelling a very large shopping center, with many tenant areas - which are like cabins - in a large space of the retail mall . these cabins are also complicated to model as theyare not aligned in straight lines but rather curved and have multiple walls.
Do Appreciate some advice of how exactly to model the tenant areas andinput their loads in a simple way.
Or perhaps not at all, as it will not make a difference to the difference between the proposed and baseline energy costs, as the tenants are modelling with identical inputs to both
The purpose of modeling tenant spaces on different meters in the model is to be able to separate the energy use in those areas from the core areas. You would not need to include each individual tenant space on its own meter in the model. You will need to separate the two in order to claim savings for anything in the core spaces beyond the envelope's impact on HVAC energy use. If you are modeling the tenant spaces identically in both models than just separate the core spaces and the tenant spaces within the model.
So how you model it will depend on where and how you are trying to show energy savings.
MPR, GFA and energy modelling
Dear All,
In the LEED MPR, it states that carpark areas cannot be part of the calculated GFA of a project submitting for LEED. I have submitting a building with a very large multilevel carpark, and have modelled the entire building with carpark for proposed and baseline energy simulation. Hence the GFA in my energy model will differ from the GFA stated in the LEED template ( which does not include the large carpark). How do we reconcile this? Hoping for some help
There is a table in the EAp2 form where you input the square footage of the various areas in the project. You break down the building into occupied and unoccupied square feet. This should be enough to explain the difference if the square footage values in the overall submission have been coordinated.
LEED Pressure Adjustment for Lab HVAC-Systems
Seems that some of my questions are not easy to answer.
Here is another question for the same lab project.
Fan system Power limitations are calculated according to Table 6.5.3.1.1A of ASHRAE 90.1-2007 Standard. Therefore credits are given for devices in the ducts of the HVAC system.
The designed lab building which we have to calculate for LEED C&S uses a diversity of devices in the ducts.
For the supply duct they use 2 filters, 6 air louvres for control, 2 cooling coils (cool+recool), 2 heating coils (heat+reheat), 1 energy recovery, and 2 sound attenuators.
For the return duct they use 1 Filter, 4 air louvres for control, 1 humidifier for adiabatic cooling, 1 energy recovery and 2 sound attenuators sections.
This results in a big fan power as documented from HVAC engineer of about 3.3 W/CFM for the supply and about 3.7 W/CFM for the Ventilators.
The question is:
Can we use the diversity of filters (2+1) and sound attenuation sections (2+2) in the design to calculate the fan power limitation of the baseline?
Regards Heinrich
Yes the hard ones require research and the polling of colleagues. As a volunteer contributor I usually get to the easy ones fast and the hard ones as time allows. This is a relatively hard one to answer.
Neither the Standard nor the User’s Manual are clear about whether you can take pressure drop adjustments for more than one filter or sound attenuation section within the same duct. Example 6-AAA in the User’s Manual indicates that you can apply a pressure drop adjustment for heat recovery devices to both the supply and exhaust airflow, so by extension you could make the argument that multiple pressure drop adjustments should be allowed for filters and sound attenuators since they increase the static pressure (and therefore fan power) of the Proposed system. Your best bet would be to request an interpretation from GBCI for the specific project in question.
Landscape lighting
Appendix G (Table 3.1) states that lighting power for building facades has to be modeled in the energy simulation. However, it is not clear if landscape lighting should also be taken into account.
Do we have to implement the external lighting of the building grounds (walkways, landscape lighting...)?
Thanks
You do have to included it. It doesn't matter if it's on the facade or on the site. As long as it's in the LEED project boundary, it is an energy consumption associated with the project. I have worked on worked on 5 LEED CS buildings within the last year and always had to included it.
airflow limitation of lab spaces during unoccupied periods
According to Ashrae 90.1-2007 G3.1.1.d there should be a fan flow limitation for lab spaces in the baseline model during unoccupied hours.
"For Lab spaces with a minimum of 5000 cfm of exhaust, use system type 5 or 7 that reduce exhaust and makeup air volume to 50% of design values during unoccupied periods"
What if the design uses a fan flow limitation of 10% of design values for lab spaces ? Can this more restrictive flow limitation be used for the proposed model. Or should the flow limitation of 50% be used, which is identical to baseline model.
Heinrich,
I believe that you can use a 10% value in your proposed case, in the same way that heat recovery that exceeds the 50% minimum can be modeled.
Back up Energy source in Energy Modeling
I have an office building that will use solar pannels to generate hot sanitary water. But it will have an electric heaters aswell for back up. How can I consider this in my Model???.
It depends on the software. Some model solar hot water and some do not. If your software does not you can do the calculations external to the software since service hot water is not an interactive system (does not affect heating and cooling energy use).
Tenant area-HVAC system type
We are modeling a Core & Shell office building where the HVAC system is in the tenant scope. we are only delivering chilled water and outdoor air to the tenant areas. We are specifying fan coil units system for tenant areas in the tenant design guidelines. My question is should we model HVAC type in the proposed design building as fan coil units or we should model it as the same type of the baseline building?
Ooptimize Energy Performance
I am not sure how to estimate a Core & Shell lighting Schedule for an office building, would somebody help me,
Thans
If you have no requirements for lighting in the lease, you will assume the lighting power density per ASHREA 90.1-2007 section 9 for the tenant spaces. Make sure to have storage room in the space also. For the common area (staircase, lobby, basement, mechanical rooms ect. you need to determined the actual lighting power density based on the lights installed in the space. This is what you will need for your energy modeling and to show compliance with ASHREA 90.1.
Leed CS for Bus Station.
The project I am working on is a bus station that has an enclosed retail area with an underground parking and an outdoor above ground parking space. The building will use natural/mechanical ventilation but no AC system, but for simulation purposes we are using a HVAC system according to Table G3.1.1A & B.
The underground parking will have some retail spaces but the outdoor parking will have lighting as the sole load
My question is:
Do I have to consider the underground parking as served by the HVAC system? What happens with the outdoor parking space, can I simulate it as external lighting?
I am using eQuest 3.64 by the way.
The parking garage that is only ventilated would not count as conditioned square footage at all and you would only model the ventilation. The retail spaces at the parking garage level would be modeled with the same system as the rest of the building based on the conditioned square footage and number of floors according to Table G3.1.1A.
Any parking lot with lighting only is modeled by including the lighting only.
How do you assign different electric meters in eQuest for tenant spaces and building core? Is it possible to graph multiple electric meters?
Hi Donovan, This is a good question to post on the eQuest users mailing list, since it's more about how to use eQuest than it is about LEED.
The client has made some changes to the original building, now I have one main enclosed building with underground parking, surrounded by a contiguous parking lot. In the parking lot there are: a small one story building for administrative purposes (gross floor areaGross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.) of 96m²), two waste water treatment plants, that serve the main building, a pumphouse for the water supply system and several guardhouses.
The auxiliary buildings serve the main building and are connected to it by the plumbing system and the lighting system.
The issue is that I don’t know if I should consider this as a multiple building project or as a single building project, since the auxiliary buildings are not contiguous to the main building but separated by the parking lot.
The MPR Supplemental Guide says that I must include the building in its entirely and that the building project must include all the land that support the normal building operation.
Also, If I consider the buildings as separate, the waste water treatment plants and the administrative building do comply with the minimum floor area but the guardhouses and the pump house have way less than the required 93m².
Should I consider the auxiliary buildings as separate projects and simulate them separately or as a single building?
The MPR Supplemental guide says that I should not include the parking garage in the gross floor area of the LEED project building. In that case what happens with all the lighting?
Thank you for your answers Marcus & Nadav, I really appreciate it .
I've been reading the MPR supplemental guide and, as I understand, we will have to submit a multiple building application. Since some of the buildings do not comply with the minimun area requirement, they won't be elegible for certification.
The water supply system, for the main certifiable building, is in one of those buildings that wont be elegible for certification. Now, my main question is if we have to exclude the water supply system of the main building and in the eQUEST simulation?
Thank You
LEED CS 2009 LEED ENERGY MODEL
My proposed system is a WSHP. However, the heat from electric exceeds the heat used from boiler in the WSHP loop.
I would condiser the primary heating source in this building to be electric, and the correct Baseline System to be System 6 - Packaged 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 PFP Boxes, Direct Exansion Cooling and Electric Resistance Heat (Table G3.1A page 180, ASHRAE Standard 90.1-2007.
The building is 120,000 sqft and 4 floors.
Is that correct? Do you agee with the selection.
Hybrid systems get modeled under the fossil fuel column so it is likely a system 5 for the baseline.
Hi Marcus, There is a note at the bottom of Table G3.1.A page 180 of the 90.1-2007 Standard that states. "Where attributes make a building eligible for more then one heating type, use the predominate condition to determine the system type for the entire building.
The building does use more electric energy to heat then natural gas energy. I was going to use this as my bases for choosing System 6. What do you think?
Existing Chiller in 100% building construction refurbishment
I am wondering how to handle an existing chiller in a LEED C&S project.
The building of the C&S project got 100% refurbishment for the building constructions.
The central chiller plant has been reused from the old building.
Can the existing air cooled chiller be used as chiller in the baseline model or do I have to use the water cooled chiller from ASHRAE table.
Thanks for your help.
Oops - no answer until now.
Is there really nobody who can answer my question ?
Any hint where i can find information or help would be appreciated ?
Regards Heinrich
You will have to the baseline from ashrae.
In our opinion the general guidance in 90.1 indicates that you only have to bring a system up to code compliance if you are replacing it. Following this logic the baseline system should be identical to the proposed for this system.
As you can see this is a gray area and there are other opinions.
If you are not replacing the chiller, then you do not need to follow the pre-requsites for EA, but i believe that you have to use the baseline as stated in ashrae, otherwise your energy saving can still be huge despite an old chiller.
ASHRAE/eQuest question - external blinds and SHGC requirement
Hello,
In a CS office building we specified SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.=0.35 (for zone 5 ASHRAE requires <0.4) as well as the external blinds/shades on the South and West elevations. Based on the HVAC engineer calculations they were not necessary on the East elevation. Neither for glare control, as the sun is gone by 10am.
Currently the client is asking if we can disregard the requirement for SHGC in the walls that have external blinds? I know that ASHRAE prescriptive requirements are not binding given we meet the required savings in the energy model – so my question is, how to model it? In eQuest there is only place to check that the automatically controlled external blinds are used.
From your experience will this be enough or do we still need a good SHGC value to show the 25% savings we initially modeled?
Thank you,
Agnes
You should model both the installed SHGCSolar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. of the glass and the automatic blinds. When in doubt always model what has been designed and built!
Neither is hard to model so include both, run the model and you will find the answer to your last question.
Demand Limiting Controls
Hi,
For the energy evaluation of EAP2 and EAC1, "demand limiting control" is accepted how energy saving strategies in the proposed model?
In this case, how would be the simulation for the baseline?
This could be eligible for demonstrating energy savings following the exceptional calcualtion method.
Ok, thank for your response, but if demand limiting control is modeled in proposed model, also must be modeled in baseline model?
Reference building - garage
In the building for which I'm preparing energy simulation, there's an underground garage which is heated only by used recirculated air from offices above. My question is if I should include it in the energy simulation? Should I set heating in the garage in the reference building model?
If the garage is within the scope of the LEED project you will have to include it in the model.
Demand-Controlled Ventilation
Hi,
in my proposed HVAC system I want to use a demand-controlled outdoor air ventilation (with motorized dampers controlled by CO2Carbon dioxide detectors).
So I will use an appropriate schedule (based on the occupancy) for this system.
The ASHRAE 90.1 App. G Table 3.1 Section 4 seems to say that I've to use the same HVAC schedules for Proposed and Baseline systems.
Should I have to use identical schedules for proposed and baseline?
I'm asking this because if I do this way I will not have any energetical improvement due to the different outdoor air regulation.
Thank you very much for your help.
Regards
Yes the schedules in the proposed and baseline must be the same.
Some software models DCV directly without having to manipulate schedules to show savings. If your software does not, you will have to follow the exceptional calcualtion method to claim savings.
Thank you for your answer.
But if the software models DCV directly, it means that it use different schedules (if not, there will not be any energy saving on primary airflow).
But if I have to use the same schedules (per ASHRAE) theoretically I'm not allowed to modulate fresh rate immission.
Really, I don't understand what I have to do.
Thank you again.
Regards
Which modeling software are you using? Does it allow you to directly model DCV? If so just model it. Typically the software bases the OA rate on the occupancy schedule so just make sure your occupancy scheule is identical in both models. SInce this is automatic and well understood no exceptional calculation is required.
If your software does not model DCV directly then you would have to make the schedule changes yourself. Since this is a violation of the modeling protocol requiring that schedules be identical, LEED will require you to follow the exceptional calcualtion method. Basically you will need to do separate calculations and write a detailed narrative explaining how you have simulated DCV.
Tenant spaces simulation without HVAC
Does anyone knows if the tenant spaces shall be simulated with HVAC system for a shopping mall or can i just simulate with idealloads?
I searched in the LEED Reference guide Appendix 2 but it does not mention anything about HVAC system for tenant spaces, just lightng and plug and process engery.
Thanks
If the HVAC for the tennant spaces is known then you can model that. If not known then the system should be the same as the baseline.
Marcus,
Thank you. We had the same question for a retail space where the HVAC system is not designed yet.
Could you please give us some insight on where you found this info in appendix G?
Thanks!
LEED Core and Shell: Energy Performance Improvement
When modeling a building under the Core and Shell system, do I have to compare the energy performance only between systems under the project scope, i.e. Core and Shell? Or do I have to compare energy performance between the entire buildings, i.e. Core and Shell + tenants? If I have to compare the performance between the entire buildings, it seems unfair to projects where the Core and Shell represent a small portion of the energy consumption (e.g. 40%). In this example, the project must improve energy performance by 25% or more (depends of the process energy consideration) on the Core and Shell systems just to meet the pre-requisite (10% improvement). Can someone give me a clarification on this?
The comparison is for the whole building even if the core represents a small portion of the building. Keep in mind that any shell (i.e. building envelope) improvements count toward the necessary savings even if only affecting tennant spaces.
Can a shell be LEED Core and Shell certified without HVAC?
I've cross posted this in the LEED CS fundamental commissioning discussion since these two issues seem to be the showstoppers.
We are working on a project that is a tenant finish-out shell. The tenant will be responsible for the HVAC system, and the developer for the shell. The tenant has asked that the shell be LEED certified. But is it even possible to LEED certify a building that has no HVAC? Or would this only be a candidate for pre-certification?
It seems like the only way to comply with EA1 and EA minimum energy prerequisite would be to use a prescriptive path for the elements of the building that apply (insulation and exterior lighting). Would that be accepted?
You can do so. Model the HVAC the same as the Baseline. The minimum savings would have to be earned through the envelope improvements and any lighting savings you can claim.
Energy simulation
Hi,
I'm running an energy simulation on a three floors office building.
This building have also an entrance hall.
The HVAC system for the office part is a VRV Fan Coil System with external air condensed units
The HVAC system for the hall is a Radiant floor type with external heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source..
I've already identified the baseline system #6 for the VRV system (per ASHRAE 90.1 appendix G table G3.1.1A).
I've to include the hall HVAC system in this VRV baseline system #6 , or I have to choose another one?
If I've to choose another one for the Hall, I've to consider the Hall surface only or the whole building area in order to identify the correct baseline system on the ASHRAE appendix G table?
Thank you in advance and sorry for my bad english.
Redy
You only model a different system if any of the exceptions in G3.1.1 apply.
IDA ICE- energy simulations
Hello:)
In which programs are you doing energy simulations? Did you have some problems with GBCI concerning the type of the programe that you chose? What with IDA ICE for example.
Thanks:)
Acceptable software is defined in 90.1 Appendix G2.2. Another often used criteria for modeling software is compliance with ASHRAE Standard 140.
I am not familiar with IDA ICE personally but it has been submitted for LEED projects.
The most common software used for LEED is eQUEST, TRACE, HAP, EnergyPro, Visual DOE, Energy Gauge, Energy Plus and IES VE.
We use eQUEST, Energy10 and EnergyPlus.
LEED CS & LEED CI - PV array
Hi,
I am working on a LEED CS project, at the same time the tenant is pursuing LEED CI (separate submission) and planning to install a PV array to achieve the 2.5% of building electricty required for LEED CI. Will the tenant also be able to claim credit for the PV array to be installed by the tenant (both owner and tenant agree to do so)? LEED CS requires only 1%.
Thanks.
Are you asking because the projects are happening concurrently? I would count the CI project as going into a building that has renewable energy for SSc1 option 2 path 11
Thanks Michelle. Yes, they are happening concurrently. Can both obtain EAc2?
I think you can count it in both. We did this on one of our projects.
LEED-CS v2.0 Title-24 2005 equivalent to ASHRAE 90.1-2004?
For projects registered under LEED-CS v2.0, is Title-24 2005 deemed equivalent to ASHRAE Standard 90.1-2004 for showing compliance with the EAc1 requirements?
It is deemed equivalent. See http://www.usgbc.org/ShowFile.aspx?DocumentID=2255
Core and Shell Definition
Can a building without a core HVAC systems be certified under LEED CS?
For example, a two story building with a 6,500 ft2 footprint per floor. The developer intends to install 80-100% of the HVAC systems. There is not any common area, corridors, lobby or conditioned utility rooms. The building is being modeled with 4 zones per floor and all of the installed HVAC systems will serve one of the future tenant zones. Each floor is a wide open space with no walls or partitions.
At present, each zone will be conditioned by a VRV fan coil with one condensing unit per floor. Temporary lighting will be installed.
What is the procedure for modeling the building if there is no core energy usage?
All energy usage gets modeled in a CS project, not just the core. In your situation the available savings will simply have to come from a more narrow pool of opportunities. Savings can be claimed for an improved envelope, more efficeincy HVAC, and lighting is there are tenant guidelies.
The procedure is the same for your CS project as it would be for any ohter.
Marcus:
Thank you for the reply.
Actually this project is using the CS V2. Per Appendix 2, the lighting and plug loads for the tenant and core spaces need to be assigned to separate electric meters.
There will be no lighting or plug loads that are not in the tenant spaces as the entire floor will be tenant space.
According to Appendix 2-1.3 " The core and shell building is all parts of the building that is not a tenant space."
Is this the wrong rating system to use for this project?
I understand that you have no "core" spaces so you have all "shell" spaces. It sounds like the efficiency of the shell affects all of the spaces so that is where you will need to get your savings. If you are installing most of the HVAC you can get savings there too.
Does not matter if it is V2 or 2009 for energy you will need to model the whole building. Do not get hung up on the area the energy is used, tenant vs core, as it all counts in the calculations. For V2 projects there is a methodology on USGBC's web site which allows you to factor out lighting and plug loads in tenant spaces.
http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2482
unmet load hours
Hi,
for the unmet load hours test there is a throttling range to be defined. As I understand from ASHRAE 90.1 there is no fixed value for this range, how shuold it be defined? Is it linked to any other setting of the system? Which could be standard/accepted values?
thank you
You are correct that there is no fixed value in 90.1. Only requirement is that it is identical in both Baseline and Proposed cases.
Many modeling programs use 2 deg F as a default - that is usually where I start. I'll only adjust it if I see funny results such as high of unmet load hours, or big reheat loads.
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