New District Energy Guidance for LEED Released by USGBC

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LEED AP BD+C, Executive Editor – LEEDuser BuildingGreen, Inc. Aug 16 2010 LEEDuser Moderator Post a Comment

Updated DES guidance is here!

For months I've been replying to campus and multi-building posts on the LEEDuser forum with statements like, "The official USGBC guidance on district energy systems in LEED is very helpful in your situation, although that guidance hasn't yet been updated for 2009 projects." I'm very glad that as of today that statement will no longer be necessary! USGBC has released Treatment of District or Campus Thermal Energy in LEED v2 and LEED 2009 – Design & Construction as a free PDF download.

If your project uses thermal energy produced from or delivered to a source outside the LEED project building, this document is required reading. Well, we think it's required reading because it's so useful. In fact, USGBC technically only requires it for LEED-NC, CI, CS, or Schools v2.x projects registered after May 28, 2008 (those projects can also continue to use version 1 of this document).

For LEED 2009 projects, the district energy guidance is recommended by USGBC, but is not (yet) formally incorporated into 2009 requirements. (Perhaps we can look for an addenda on this in October 2010.)

The document looks great. Particularly helpful is a section at the beginning that shows what's new in this version. Here are some tidbits:

Changes to Enhanced Commissioning (EAc3)

1. Clarification has been provided regarding system commissioning for district plants that include additions plus existing equipment.

2. Requirements have been changed slightly to align more closely with EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. commissioning requirements.

Changes to Energy Efficiency (EAp2 / EAc1) – Performance Path

1. The modeling protocols that were called “Step 1 and Step 2” in the Version 1.0 guidance have been recast as “Option 1 and Option 2” in the new guidance. Now each project team chooses one of the two performance options to show compliance with both EAp2 and EAc1; no team is required to do both. This is an important change, and is intended to offer LEED customers more flexibility and simplicity.

2. The Combined Heat and Power An integrated system that captures the heat, otherwise unused, generated by a single fuel source in the production of electrical power. Also known as cogeneration. (Adapted from U.S. Environmental Protection Agency)(CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source.) guidance for district energy systems is incorporated into this document.  The CHP guidance has also been modified to provide defaults when efficiency values are not available, and to clarify how the energy generated from the CHP plant is distributed between projects.

Your thoughts?

What do you think of the updated guidance on district energy? Anything that will help or hurt your project? Please comment below.

78 Comments

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Michael Wahjudi ESD Consultant Kaer Pte Ltd
Nov 22 2016
Guest
250 Thumbs Up

Campus Thermal Energy Plant Submission

Project Location: Singapore

Hi. We have LEED Campus Development with 2 LEED projects inside. Let's call it "Development F" and "Development A". Development F is housing the thermal energy plant, hence exception for option 2 is applicable. We have run simulation on both option and the savings are not eligible for both options.
Under opt. 1: Development F achieves 6% and Development A achieves 9%
Under opt. 2: Development F achieves 18% and Development A achieves 20%
How we should address this situation? Since we can't fit at both options

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Marcus Sheffer LEED Fellow, 7group Nov 23 2016 LEEDuser Expert 69162 Thumbs Up

I am not sure I understand the problem that is preventing the fit you are referencing? Point cap/point floor? 18% minimum? Could you be a bit more specific.

Keep in mind you are not required to use the DESv2. You can use 90.1-2007 with addendum ai instead.

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Michael Wahjudi ESD Consultant, Kaer Pte Ltd Nov 23 2016 Guest 250 Thumbs Up

Hi Marcus. Under opt.1: we still required to meet 10% minimum savings. Hence it is not possible. Under opt. 2: we required to meet point floor of 6. Since our development is NC. Hence we required to meet 22%. Is my understanding correct?

If we can use 90.1-2007 directly, how we should declare the energy consumption of campus thermal energy on each development? By their ratio of building cooling load?

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Marcus Sheffer LEED Fellow, 7group Nov 28 2016 LEEDuser Expert 69162 Thumbs Up

Got it. You are in an awkward spot.

Using addendum ai will probably not help enough to get you over 10%.

You could ask GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). to grant you an exception to the point floor. I am not sure how that would be received. You could ask them if you could earn the prerequisite without any points under Option 2.

The obvious answer would be to improve the energy efficiency of the projects to increase the percent savings.

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Michael Wahjudi ESD Consultant, Kaer Pte Ltd Nov 28 2016 Guest 250 Thumbs Up

Thanks Marcus. Yes, we have tried to clarify with GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). on this situation.

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Valentin Grimaud Thermal Engineer TERAO Green Building Engineering
Jun 16 2016
LEEDuser Member
1335 Thumbs Up

DES Rates

We are working an a project about a building using purchased hot water and purchased chilled water from DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity.. It is a Building Stand-Alone Scenario (Option 1) as all upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site. belong to the DES and are not included in our project.

We are not sure about the way to calculate the Virtual Energy Rates as it is explained in the section 2.4.2.1:
- To calculate the Virtual Electric Rate when the rate is not flat, do we have to include the demand charges in the annual energy cost? The annual electric cost should be divided by the annual electric consumption provided by the preliminary run of the Baseline?
- To calculate the Virtual Fuel Rate (that we need to obtain the District Hot Water Rate), which Fuel is this about? The connected building does not use fossil fuel. What energy consumption do we have to use then?

Thanks a lot.

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Marcus Sheffer LEED Fellow, 7group Jun 21 2016 LEEDuser Expert 69162 Thumbs Up

- Yes a flat rate is just the overall cost/unit of fuel. A not flat rate breaks the rate down into its component parts like you would when modeling an electricity tariff for example. This complex rate then gets applied within your baseline model. The output from that model will provide you with the virtual rate. Basically you are converting your complex rate into a flat rate.
- It is about the fuels listed in the formula. In the case of hot water it is the fuel rate and the electric rate. If the building does not use fossil fuel you can apply the exception and use a flat rate.

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Jamy Bacchus
Mar 02 2016
LEEDuser Member
26 Thumbs Up

MBTU = 1 million BTU, which is also MMBTU

It's come to my attention that there's some unit confusion in the LEED Treatment of District Thermal Energy Guide where DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. virtual rates are calculated.

The Guide includes equations on page 14 in units of MBTU but doesn't clarify the meaning of "MBTU". The Canadian equivalent of this Guide is CaGBC's "The LEED Canada 2009 Interpretation Guide for District Energy Systems (DES)". The Canadian version uses similar equations (but the steam and hot water conversions notably don't have an electricity term). But while the equations look the same, they use MMBTU as the units. They do take the extra step to note: MMBtu = 1 million Btu.

MBTU commonly means mega or "M" BTU (x10^6) or 1 million BTU. But it sometimes means "M" for mille or Roman numerals M, which is (x10^3) 1 thousand BTU. Using this latter notation MM is 1 thousand, thousand (x10^3 x10^3) or 1 million.

My interpretation is that the USGBC's DES equations mean MBTU = 1 million BTU.

I know that was stressing a lot of people out. And with that said, let's all go metric.

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Marcus Sheffer LEED Fellow, 7group Mar 03 2016 LEEDuser Expert 69162 Thumbs Up

Your interpretation is correct!

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Mike Stopka Director of Sustainability Solomon Cordwell Buenz
Aug 10 2015
Guest
747 Thumbs Up

new chiller plant to be added with new project

Hello

I was told by our engineers that in order to use a chiller plant, it needed to be documented for at least 1 year of operation.

Is it possible to take advantage of a new chiller plan to be built in coordination with the new project being documented for LEED certification?

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Marcus Sheffer LEED Fellow, 7group Mar 03 2016 LEEDuser Expert 69162 Thumbs Up

Sorry I missed this one.

See Appendix C in the DESv2. There is a modeling method for Option 2.

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Scott McMillan
Jun 24 2015
LEEDuser Member
117 Thumbs Up

Treatment of shared chiller plant

We have a central chiller plant generating chilled water to serve a hotel and a convention centre. Only the convention centre will be seeking LEED certification under LEED NC 2009. We have a couple of queries:
1. Is it compulsory to account for shared chiller plant and the associated change in part load efficiencies, increased pumping energy etc? It would be more conservative not to account for as part load efficiency would tend to be lower and pumping energy higher as the cooling load increases serving two buildings.
2. If it is compulsory do we need to follow the methodologies in the DESv2 doc or can we construct our own methodology?
3. Is the most recent version of the DESv2 doc the August 2013 publication?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Jun 25 2015 LEEDuser Expert 69162 Thumbs Up

1. It depends on the methodology you choose.
2. You have three previously accepted options - DESv2 Option 1, DESv2 Option 2 or ASHRAE 90.1-2007 Addendum ai. Constructing your own methodology is acceptable but farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters). riskier since there is a chance that your methodology may not be accepted. If you create your own I would suggest you get some level of approval through a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org..
3. DESv2 was published August 13, 2010. I am not familiar with an August 2013 version. Do you have a link to it?

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VEL MUTHU
Apr 17 2015
Guest
178 Thumbs Up

DES system in a extremely hot and humid climate.

I am working on an underground building project aiming for LEED NC gold/platinum. Project design feasibility showed that 25% energy saving can be achieved with little effort as the HVAC design parameters were selected taking into account of sustainability and energy saving targets. Project considers district cooling plant chilled water as cooling source with no heating source in the design. District cooling is considered in the design to achieve the energy saving target as the project location pushed the client to not to go with water - cooled chillers due to limited water availability.

We opted for option 2; reasoning being the point cap when considering option 1 and our targeted point for EAC1.

Our project’s design parameters are quiet efficient in terms of envelope (don’t think it will affect the saving as the project building is almost 80% underground), efficient HVAC systems (ERU units with FCUs and with district chilled water system). Due to un-availability of DES details, we considered 4.4 as plant COP for proposed case as per the assumptions referenced in ‘Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design & Construction’. Baseline is done based on ASHRAE 90.1-2007 with System 8 and chiller of 6.1 COP. The results are not as expected showing a different pattern. I have some questions which are listed below.

1. Is there any way to model the proposed system to account for cost of the energy source i.e. to account for the impact of chilled water/energy cost alone?

2. Comparing a water cooled chiller with 6.1(COP) in Base with 4.4 plant COP for proposed doesn’t look fair. When we calculated the overall plant COP for Base case it comes around 5.5 a much higher COP than 4.4(proposed plant COP). But in actual cases, district chilled water plant is much more efficient than a standalone chiller. This questions the performance of the district chilled water systems and opting out from such options. Correct me if I am wrong.

3. In general, water cooled chillers are not a feasible option in very hot and humid condition. Projects will opt for air cooled chillers or district energy systems in these areas. A COP of 6.1 with water cooled centrifugal will prove both the options less efficient in terms of energy savings. Correct me if I am wrong.

4. I am modelling my project based on the document referenced above. Is there any other option or method which is accepted by USGBC to do simulation with district chilled water systems.

5. What are all the areas, I need to check in my energy model to make sure of the system and plant side parameters for this scenario?

I can understand my questions might take lot of your time. But you suggestions and comments will help me a lot.

Thanks a lot for your time.

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Marcus Sheffer LEED Fellow, 7group Apr 20 2015 LEEDuser Expert 69162 Thumbs Up

1. Not sure I understand the question
2. The default efficiency is low on purpose because some DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. plants are inefficient so using the low value is conservative and encourages project to determine the actual plant efficiency.
3. That sounds right but there is no exception for hot/humid climates.
4. You can use ASHRAE 90.1-2007 addendum ai which treats the chilled water as purchased energy and eliminates the point floor and cap.
5. This would vary depending on the software.

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rodd borgogno mechanical engineer, state of californiat Apr 20 2015 Guest 95 Thumbs Up

I am actually trying to determine the COP of our cooling only DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. plant.
We are measuring the Energy used by the plant (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.) , and the energy produced by the plant (BTUh).
Question: If I have a years worth of data, can I just use the annual BTUh divided by the annual KWh to determine the average annual COP of the plant, and then use this COP in my energy model?

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Marcus Sheffer LEED Fellow, 7group Apr 20 2015 LEEDuser Expert 69162 Thumbs Up

See Appendix C in the DESv2. Your method seems to be in alignment with one of the allowable methods.

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Elodie DUMAS ALTO Ingénierie
Mar 10 2015
LEEDuser Member
1042 Thumbs Up

DES heating and cooling plant using a unique heat pump

Hi
We work on a project pursuing Leed C&S 2009 certification in France. The building is connected to a heating and cooling DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. (one facility), and we consider option 2 for calculations regarding credits EAp2 and EAc1. This DES is supplied only by electricity (chilled and hot water are produced simultaneously by the same group of heat pumps with a sea water loop as a heat/cold sink).
According to Ashrae 90.1 appG and Treatment of DES v2.0, the heat plants would be :
- onsite gas boiler (systems 7) for the baseline
- virtual DES plant which uses electricity
It sounds strange to count, for heating consumption, gas rate for baseline and electricity rate for proposed. (There is no gas in the proposed).
Thanks for your help

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Marcus Sheffer LEED Fellow, 7group Mar 10 2015 LEEDuser Expert 69162 Thumbs Up

I am not sure how you are coming up with a system #7. Under DESv2, option 2 you model a virtual heating and cooling plant according to Table G3.1.1A. If the proposed heating is electric then the baseline heating is electric.

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FABIO VIERO Head of Sustainability Manens-Tifs s.p.a.
Dec 11 2014
LEEDuser Member
1372 Thumbs Up

DES Options application restriction

We are certifying a Hospital according to LEED 2009 for Healthcare yet to be registered. The hospital is part of a larger scale project which is not being LEED certified as a whole (we are certifying the hospital building only). A new district heating and cooling plant is being built as part of the larger project and will serve most buildings of the project including the hospital. The district plant is located outside the LEED boundary of the Hospital. Could you please confirm that both Option 1 and Option 2 of the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guideline (issued on August 13 2010) are available to the project? Can you confirm there no restrictions to this choice between the two options due to the project owner is one, in other words the same owner for the hospital and the district plant?

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Marcus Sheffer LEED Fellow, 7group Dec 11 2014 LEEDuser Expert 69162 Thumbs Up

Hey Fabio,

I do not see any reason why both options would not be available.

Off the top of my head the only place ownership enters the situation is when there is a CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. plant (see guidance in the Reference Guide).

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May Xu
Mar 19 2014
LEEDuser Member
38 Thumbs Up

Purchased Energy Rate

We are working on a project consisting of several offices and residential buildings, but LEED boundary is considered only one of the office building. There are 4 ground source heat pumps intended to provide heating and cooling for the whole project, which is considered as "upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site.". therefore, we are thinking to follow option1 or as an alternative path applying ASHRAE 90.1-2007 addendum ai.

However, I'm confused how to determine the purchased energy rate when the local purchased energy rates is not available. The rates must account for the total costs associated with maintaining the district equipment, and generating and delivering the energy to the project site. Do I need to create another testing model that includes all the buildings outside the LEED boundary to calculate the performance (cost $ /electricity consumption 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.) of the upstream equipment? Or is there any other method to get the rate?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Dec 11 2014 LEEDuser Expert 69162 Thumbs Up

You do not need to create a model that includes all the buildings. The way you calculate and determine the rate is spelled out in section 2.4.2.1 of the DESv2.

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May Xu
Mar 19 2014
LEEDuser Member
38 Thumbs Up

We are working on a project

We are working on a project consisting of several offices and residential buildings, but LEED boundary is considered only one of the office building. There are 4 ground source heat pumps intended to provide heating and cooling for the whole project, which is considered as "upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site.". therefore, we are thinking to follow option1 or as an alternative path applying ASHRAE 90.1-2007 addendum ai.

However, I'm confused how to determine the purchased energy rate when the local purchased energy rates is not available. The rates must account for the total costs associated with maintaining the district equipment, and generating and delivering the energy to the project site. Should I create another testing model that includes all the buildings outside the LEED boundary to calculate the performance (cost $ /electricity consumption 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.) of the upstream equipment?

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group Mar 23 2014 LEEDuser Expert 69162 Thumbs Up

Section 2.4.2.1 in the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. v2 explains the rate calculations for Option 1.

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JOSE RAMON TAGLE COMMISSIONING & LEED AKF MEXICO SRL DE CV
Feb 14 2014
Guest
315 Thumbs Up

Do I have to use DES Guidance?

We´re working on a Resort LEED Project (one owner) conformed by a Hotel, service buildings, SPA and villages, LEED boundary is considering only Hotel and Service Buildings, however, Cooling Plant (3 chillers) will provide chilled water to the whole resort, therefore, is it required to use DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guidance for EAp2 and c1 documentation?

If it is required to use DES guidance, option 2 will be followed, which consists on considering upstream and downstream equipmentThe heating and cooling systems, equipment, and controls located in the project building or on the project site and associated with transporting the thermal energy of the district energy system (DES) into heated and cooled spaces. Downstream equipment includes the thermal connection or interface with the DES, secondary distribution systems in the building, and terminal units. Drift water droplets carried from a cooling tower or evaporative condenser by a stream of air passing through the system. Drift eliminators capture these droplets and return them to the reservoir at the bottom of the cooling tower or evaporative condenser for recirculation., we assume upstream refers to all HVAC equipments out of the LEED boundary connected to the Cooling Plant and downstream to all HVAC equipment located into LEED Boundary, including the Cooling Plant (Which is inside the LEED Boundary), Does the Energy Model has to consider the whole project eventhough upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site. are located outside of the LEED Boundary?

If it is not required, we were thinking to generate an Energy Model considering only the buildings into de LEED boundary (Hotel and service buildings), a second Energy Model could be generated in order to confirm Space Cooling energy consumption of the rest of the buildings located outside of the LEED boundary and then include this energy consumption on the first Energy Model as a process load. Is this strategy correct?

Thank you very much,

Regards.

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Marcus Sheffer LEED Fellow, 7group Feb 17 2014 LEEDuser Expert 69162 Thumbs Up

Under LEED 2009 the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. is optional.

Under Option 2 you include the upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site..

No you do not model a process load for the buildings on the plant outside the boundary. You simply model the chilled water as purchased energy. The baseline varies depending on whether you are applying ASHRAE 90.1-2007 Addendum ai or not.

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JOSE RAMON TAGLE COMMISSIONING & LEED, AKF MEXICO SRL DE CV Feb 19 2014 Guest 315 Thumbs Up

First of all, thank you for your comments Marcus, however, I´ve got one more question regarding purchased energy.

The situation is that the Project will not purchase the energy because Chilled Water Plant (located into de LEED boundary) will belong to the Resort.

Do I still need to model Purchased Energy?

Thanks Again

Regards

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Marcus Sheffer LEED Fellow, 7group Feb 19 2014 LEEDuser Expert 69162 Thumbs Up

You model it as if it were purchased energy even though you will not technically be buying it. The rate to use would be the resort's cost to produce the chilled water.

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Yuna Chen
Feb 05 2014
LEEDuser Member
33 Thumbs Up

Do I model part-load curve for the DES default efficiency?

The DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guideline (2010) allows us to model DES cooling plant with a COP of 4.4, which includes cooling towers and primary pumps. When we use this default efficiency, can we still apply a part-load curve? (something like 90.1 default curve) Or is it an average efficiency which already count for all part-load and full-load condition? (in which case we need to apply a flat curve to the cooling plant) Thanks.

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Marcus Sheffer LEED Fellow, 7group Feb 10 2014 LEEDuser Expert 69162 Thumbs Up

It is an average efficiency so the curve is flat.

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Adam Barker
May 29 2013
Guest
168 Thumbs Up

DES option 1 points cap and EAc2 Renewable energy

Under Option 1 of the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guide, there is a 10 point cap. I have a project connected to a district chilled water system that I have modeled following option 1 which is showing 8 EAc1 points. However, this project also has a fairly large on-site PV system, which bumps us up to 18 points.

Is this allowed, or should it be capped at 10?

The DES guide gives guidance on how to deal with upstream renewable energy, but not on-site renewables in this context. Keep in mind the DES is chilled water compared to PV system which provided electricity, so my thought is that they are realtively unrelated and the points would be allowed. I've had a similar situation here in Canada and we ended up accounting for the DES as per our DES guide, then accounting for a large PV system on top of that: i.e. in isolation of the DES and any DES rules / guides.

Thanks in advance.

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Marcus Sheffer LEED Fellow, 7group May 29 2013 LEEDuser Expert 69162 Thumbs Up

I would think that the cap is before the on-site renewables. However, the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. in entirely optional. You would simply follow the same method as Option 1 by following the guidance in Appendix G. Since you are not following the DES there would be no cap and you can easily claim the PV output without question.

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Ramesh Narayanan
May 21 2013
Guest
864 Thumbs Up

Regarding LEED certification for District Cooling Plant

Hi
I am doing the energy modelling for district cooling plant which is consists of chiller room, pump room, thermal energy storage tank room & small office within it using option2. I would be required two clarification for this type of building.
1. The chiller & pump would be available within the project intended to server for many building around the project proposed for LEED.In this case how the equipment load or connected load of chiller & pump could be considered in the energy modeling. If I consider the total chiller & pump load, then acheiving 14% is not at all possible. Shall i consider 25% as the process load?

2. Based on the building total conditional area sq.ft, the system 6: Packaged Varaibale Air Volume with parallel fan powered boxes needs to be considered for the baseline case. However considering the major area of the building with chiller & pump room, whether any other system like packaged single zone (constant volume) could be considered for the baseline case?

Thanks & Regards
Ramesh Narayanan

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Marcus Sheffer LEED Fellow, 7group May 21 2013 LEEDuser Expert 69162 Thumbs Up

1. Never arbitrarily set the process load to 25%. Always model what is present in the building. One way to do this would be to include all the equipment as a process load, establish a reasonable baseline and then attempt to claim savings based on the plant being installed. Not sure how else to approach it. Have you checked the LEED Interpretations?
2. If any of the exceptions in G3.1.1 apply then you may be able to use an alternative system.

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Melissa Crowe Project Engineer, Engineered Solution Inc. May 21 2013 Guest 93 Thumbs Up

If the plant is in the building then, if you use the 2009 DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. Guide with the Option 2 path then the plant equipment is "Upstream". I just did a CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. plant building where 98% of floor space is associated with the plant. There is a small office. I had very little process energy. I had a lot of savings mostly due to lighting. I will let you know if the review takes exception to the lack of process energy.

I also did not model the proposed ventilation for the mechanical spaces per the design, as I consider the HVAC system as designed as integral to the plant processed. So I modeled fans, cooling and heating auto sized same as Appendix G base case. Don't know if that last bit will fly. Any opinions?

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Marcus Sheffer LEED Fellow, 7group May 21 2013 LEEDuser Expert 69162 Thumbs Up

Under DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. Option 2 you need to account for the upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site.. The central plant is the headwaters! Sounds like you ignored the central plant equipment and did not even model the project as designed which violates Table G3.1-1 Proposed. Will be interesting to see if either one flies.

I am not certain the best way to do this - anyone done one and had it accepted?

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Melissa Crowe Project Engineer, Engineered Solution Inc. May 21 2013 Guest 93 Thumbs Up

Marcus - I guess my explaination was not clear. For the record, we did model the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source., as upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site., but only inculded the portion of the plant energy associated with the heat used in the building and therefore only used the electricity generated when using the thermal energy (tracking thermal). Since the equipment is in the building distribution losses are negilgible. The violation may be in not modeling the actual fans.

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Marcus Sheffer LEED Fellow, 7group May 21 2013 LEEDuser Expert 69162 Thumbs Up

Did you model the CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. equipment as a load in the associated spaces? Not only are you required to model the systems as designed but you must model the process loads as designed too (Table G3.1-1 Proposed (a)). This does get very difficult as the DES was written for a project served by a DES/CHP not necessarily housing one.

If you model the whole plant, treat most of it as process, and try to claim some savings related to process as an exceptional calculation, I could see how this would work within the rules.

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Melissa Crowe Project Engineer, Engineered Solution Inc. May 21 2013 Guest 93 Thumbs Up

There is no way we can get process energy savings if we did it that way. This is for a hospital and the actual plant process energy is 2 orders of magnitude greater than the CUP building energy [including lighting, HVAC and office (200 SF) equipment]. I did not include the thermal loads for the plant. Only lighting. We submitted a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide and based on the answer I believe that we treat the equipment as upstream and therefore not in the building. I noted the lack of process energy and they did not take exception. This was/is indeed tricky,...we will see.

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Ramesh Narayanan May 22 2013 Guest 864 Thumbs Up

Thanks for all your response.

1. The plant room within the building having the chiller & pump for 45000 TR (since district cooling plant which would serve the whole development around that). But the TR requirement for the particular would be around 500 TR only. In this case how much process load should consider for the plant or pump room. For small office area, i could consider 2 w/sq.ft as a miscellaneous load. But for plant & pump room what would be the appropriate process load?

2. Kindly advise on the system selection since the inside temperature. operating hours etc. would be differ between plant room & office area.

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Marcus Sheffer LEED Fellow, 7group May 22 2013 LEEDuser Expert 69162 Thumbs Up

Fundamentally you need to know how best to approach this situation. I would suggest that you look through the LEED Interpretations to see if there is any help there. If not I would submit an Interpretation to GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). with a thorough explanation of how you think it should be done. Sounds like Melissa has done so but the project has not yet been reviewed.

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BH .
Apr 19 2013
Guest
1185 Thumbs Up

DES supplied by CHP

Hi I am working on a new development in Warsaw which will b supplied from the district heating system. DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. is supplied by CHPCombined heat and power (CHP), or cogeneration, generates both electrical power and thermal energy from a single fuel source. which are supplied by biofuels maybe in 10%. Can this portion of energy (10%) can be counted towards EAc2 ? and EAc6 ? I haven’t’ found any note in the Guidance which will forbid that…

Thanks for Help

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Marcus Sheffer LEED Fellow, 7group Apr 19 2013 LEEDuser Expert 69162 Thumbs Up

Potentially yes. Both credits are addressed in the DESv2 document with specific guidance on how you do it.

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Lauren Sparandara Sustainability Manager Google
Feb 18 2013
LEEDuser Expert
19926 Thumbs Up

Title-24 and DES

Hello, I have taken a look at Appendix B which includes Title-24 guidance within the District Thermal Energy LEED Guidance document. However, we had received the following reviewer comment and I just wanted to make sure that it's outdated. It seems to say that you cannot take credit for DES when using Title-24. Maybe I just need help in understanding: can you take credit for DES when using Title-24?

"The project team has stated that they have followed the document Required Treatment of District Thermal Energy in LEED-NC version 2.2 and LEED for Schools, version 1.0; (DES v1) dated May 28, 2008. In accordance with USGBC guidance, this approach should not be used with Title-24 modeling.; Projects with district energy plants that are documented using Title-24 2005 in lieu of ASHRAE 90.1-2007 are NOT required to follow the energy modeling guidance provided in the document "Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 Design and Construction"; (DES v2) dated August 10, 2010 which can be accessed at: http://www.usgbc.org/ShowFile.aspx?DocumentID=7671.

However, Title-24 2005 does not allow credit for the efficiency of district energy systems. Therefore, if the project is taking credit for the efficiency of the district energy systems serving the project, then the DES v2 document referenced above must be followed in its entirety.

Please revise the model to follow the Option 2 requirements defined in the DES v2 document. Otherwise, confirm that the Proposed case plant inputs represent the default Title-24 inputs, and no central plant has been modeled for the Proposed case in the Energy Pro software. Update the form and Table 1.4.1 through 1.4.6. Attach Title-24 compliance forms (PERF-1, ECON-1, UTIL-1 and OLTG) as well as BEPS, BEPU and ES-D reports for the Baseline and Proposed cases to confirm correct modeling and reporting."

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Mar 21 2013 LEEDuser Moderator

Lauren, sorry, but I"m not sure of the answer to this one.

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rodd borgogno mechanical engineer, state of californiat Apr 09 2013 Guest 95 Thumbs Up

I received the EXACT same comment on a recent project. Has anyone discovered where Title 24 excludes DES credits? In 2007 I submitted Title 24 calculations using a DES and its associated energy savings and it was approved. No comments were made about DES not being allowed in Title 24.

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Marcus Sheffer LEED Fellow, 7group Apr 19 2013 LEEDuser Expert 69162 Thumbs Up

The review comment says that DESv1 cannot be used with Title 24 but DESv2 can be used. So the most recent DES can be used for Title 24 projects, see Appendix B for further guidance.

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rodd borgogno mechanical engineer, state of californiat Apr 19 2013 Guest 95 Thumbs Up

Thanks Marcus.
I can't find any DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. information in the Title 24 literature that states DES is not allowed to be used in a model. I would like to know where the reviewer found this information. If I am showing compliance with Title 24, and USGBC has approved Title 24 as an equal to ASHRAE 90.1, then I shouldn't need to recreate my model.

I realize the USGBC is giving me an option to model the DES, but the issue is that I don't have the time or money to create the 90.1 model in order to show the energy savings.

My question is probably better suited for a Title 24 forum instead of a LEED forum, but if anyone has any information on how to show Title 24 compliance for a building that is connected to a central plant I would love to hear about it.

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Marcus Sheffer LEED Fellow, 7group Apr 19 2013 LEEDuser Expert 69162 Thumbs Up

This issue is a LEED rule not a Title 24 rule. You don't have to do a 90.1 model, just follow the Title 24 guidance in the DESv2 as it relates to your already existing Title 24 model.

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Eddy Santosa Lead Building Performance Analyst, Callison Apr 24 2013 Guest 3867 Thumbs Up

Lauren, In my understanding, You can use option 2 if you want take advantage of the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity.. You can see page 20 of the guideline. In order to follow the guideline, you may need to have 2 energypro files to address the issue.

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rodd borgogno mechanical engineer, state of californiat Apr 24 2013 Guest 95 Thumbs Up

Based on the research I have done, Appendix B of the DESv2 (page 20 of the guideline) states that you can either change the proposed equipment to match the Baseline equipment (Option 1), or you can develop a "virtual DES-equivalent plant" (Option 2). To develop the virtual DES-equivalent plant you need to model per the guidelines given in the main body of the DESv2 text. These guidelines have you creating a 90.1 model, and following Appendix C of the DESv2 guidlines. Appendix C says you either need to use actual energy data from the central plant and the served buildings or you can model the central plant and all of the connected buildings. If you don't have the energy data, then you have to model the central plant, and you must do this based on 90.1 Appendix G.....and round and round you go...........bottom line, as farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters). as I can tell you have to have an ASHRAE 90.1 model if you are going to try to take credit for a DES system.
If someone has a different (and easier?) understanding of what the USGBC is trying to make us Title 24 users do, it would be great to hear.
Thanks.

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Eddy Santosa Lead Building Performance Analyst, Callison Apr 24 2013 Guest 3867 Thumbs Up

Option 1 : basically you need to model per Title 24 ACM manual which excludes the existing DES.
Option 2 : your baseline is based on option 1 so you don't need to worry about making the baseline per ASHRAE 90.1. However, you need to make another model of your proposed case by inputting the central plant per the guideline.

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YP Pierce
Feb 05 2013
Guest
423 Thumbs Up

Green Power Requirement per DES Guidance

Could anyone help me understand the green power requirement for a project using energy model Option 1 for EA c1 per DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guidance, please?

I looked up page 18 on the DES document but not quite sure how to calculate the required green power contribution.

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Mar 21 2013 LEEDuser Moderator

YP, can you say anything more about the nature of your confusion?

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Irina Foster AECOM ME
Dec 17 2012
LEEDuser Member
54 Thumbs Up

Treating CUP as a DES?

Hi,

I am working on a LEED Healthcare project. The hospital building is phase 1 of a number of phases within a large master plan area. The Central Utility Plant will supply energy to the entire master plan area and is located in a separate building, adjacent the hospital. The CUP is currently excluded from our LEED boundary.

Is it required that we follow the guidance in the USGBC Document: Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design & Construction (Aug 13,2010)?

If we follow this guidance, does the CUP need to be modeled? Does commissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. of the CUP have to be carried out?

Alternatively, is it possible not to follow this guidance and treat the CUP as a DES?
Many thanks in advance for your help.

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Marcus Sheffer LEED Fellow, 7group Dec 17 2012 LEEDuser Expert 69162 Thumbs Up

You are not required to use it.

The CUP's performance would need to be simulated if you follow Option 2 in the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity.. Does not mean you need to model the whole CUP.

It does not have to be commissioned for EAp1. There is guidance in the DES document regarding the Enhanced CommissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. credit on page 8.

The CUP sounds like a DES, suggest you read the definition on page 6.

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Irina Foster AECOM ME Dec 24 2012 LEEDuser Member 54 Thumbs Up

Marcus, thank you very much for the clarification.

Merry Christmas!

Irina

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Susan Walter Specifications Director, Populous Dec 24 2012 LEEDuser Expert 22593 Thumbs Up

I am agreeing with Marcus. The CUP does sound like a DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. situation but only if you are not building that CUP as part of the project and it does not read like you are.

Food for thought; you may want to do some commissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. in the CUP anyways. Hospital systems are complex and if the size of your project is any indication, likely to be pretty old as well as inadequate. The systems there may need a higher degree of technical introspection. If your owner is looking for operation efficiency and controls and they are not present in the CUP, you'll need to start discussing the situation with them. One of our clients has a late 1960's era CUP at their hospital and it took me 5 years of discussing different metering, monitors, controls and cost savings strategies before they finally said OK. They went from not demanding meters to demanding it for all their projects.

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Ramesh Narayanan
Nov 04 2012
Guest
864 Thumbs Up

Default efficiency of 4.4 COP for Option 2

Hi

I would like to do the energy modelling using option2 to achieve maximum points. In this case, base case will be modelled with Packaged Terminal Air conditioner (As the residential building). For proposed case i would like to use the default efficiency of 4.4 COP to evaluate chilled water cost based on the utility rate. Please confirm whether using default efficiency of 4.4 COP instead of virtual plant average efficiency will be accepted?

Other query is if i am modeling using option1, then 4 pipe fan coil needs to be modeled for base case. In this case the whether the fan power could be modeled with 0.00094 bhp/cfm as per Ashrae table G3.1.2.9.

Regards
Ramesh Narayanan

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Marcus Sheffer LEED Fellow, 7group Nov 06 2012 LEEDuser Expert 69162 Thumbs Up

2.4.1.2.3 Default Efficiencies in the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. clearly allows the use of this default value in lieu of the actual efficiency.

No that fan power value is for a system 3 or 4. In your case it is still a system 1 and follows the fan power calculation - Pfan = CFMS ⋅ 0.3

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James Del Monaco Sustainability Director, PE P2S Engineering, Inc.
May 02 2012
Guest
885 Thumbs Up

Separate Heating and Cooling Plants

Our project is located on a University campus with two separate DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. buildings. One DES building houses all the chilled water equipment including chillers, pumps, cooling towers, etc. and only provides chilled water. There is a separate DES building which houses all the steam equipment. The DES Guidance indicates that for EAc3 we must commission all upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site. if "the DES supplies energy constituting more than 20% of the project building's annual energy cost, as determined using the Proposed Case energy modeling run of either the EAc1 Option 1 or Option 2." Should we be viewing the chilled water plant as one DES and the steam plant as a separate DES? In our case, the CHW plant accounts for 19% of the energy cost of the building and the Steam plant accounts for 9% of the energy cost of the building. Separately, these two plants are less than 20% of the energy cost but combined they would be greater than 20% and thus require commissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. of the DES. Because these are separate systems, should we be required to commissiong both even though separately they do not account for 20% of the cost? Is there a reason to commission the Steam Plant in this situation? The guidance document does not get detailed enough to answer this question nor are there any CIRs addressing this. Any thoughts? Also, even if the steam(or HHW) and CHW equipment are located in the same physical building, should they be viewed as separate plants?

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James Del Monaco Sustainability Director, PE, P2S Engineering, Inc. Sep 10 2012 Guest 885 Thumbs Up

As a follow-up on this item, we received a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide ruling on this question. In our case we have CHW from one plant and steam from a 2nd plant. In the eyes of the USGBC, the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. plant is the combination of the CHW plant and steam plant. Since this is how they view it, we would need to commission both plants. Here's the CIR ruling:

"The applicant is requesting clarification as to whether the project meets the enhanced commissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. exception for the DES energy contributing less than 20% of the building’s annual energy cost based on a three separate DES plants contributing less than 20% individually or if the exception applies to a total DES contribution of over 20% of building annual energy cost. Per the “Treatment of District or Campus Thermal Energy in LEED v2 and LEED 2009, August 13, 2010” a DES is “a central thermal energy conversion plant and transmission and/or distribution system that provides thermal energy (heating via hot water or steam, and/or cooling via chilled water) to more than one building…” In this case, the DES system is the steam and chilled water. Therefore, if the project building’s 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.) is greater than 50,000 square feet, the DES’ total contribution as a whole contributes to more than 20% of the project building’s annual energy cost and either the project building is pursuing points under EAc1 using the performance path or the project building’s connected load is 50% or more of the DES total connected load or expected connected load at the date of the project building’s substantial completion, all upstream equipmentA heating or cooling system or control associated with the district energy system (DES) but not part of the thermal connection or interface with the DES. Upstream equipment includes the thermal energy conversion plant and all the transmission and distribution equipment associated with transporting the thermal energy to the project building or site. associated with serving the project building must be included in the scope of EAc3."

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Jeremy Rapoza Engineer BVH Integrated Services
Apr 20 2012
LEEDuser Member
233 Thumbs Up

Confusion over Baseline DES Distribution Losses

The guidance document seems very clear that the proposed design distribution losses are to be included when using option 2. In our case the facility has measured them so this part is simple.

However, there seems to be no mention of including any losses at all for the baseline plant. The guidance doc references App G, which states do not include losses for baseline and proposed (which is superseded by the Guidance document for the proposed) and it references ASHRAE 90.1 table 6.8, which of course includes chiller and boiler min efficiencies.

Does this really mean that the baseline case in option 2 should be modeled with no distribution losses?

Could one assume that because pipe insulation thicknesses are listed in Table 6.8, then we can do a calculation of what a baseline maximum pipe loss would be based on baseline minimum pipe insulation and operating temps and pipe sizes?

Any ideas, I searched the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide's and could not find anything on this.
.

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Marcus Sheffer LEED Fellow, 7group Sep 06 2012 LEEDuser Expert 69162 Thumbs Up

Since the proposed in the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. option 2 includes the upstream central plant and the baseline does not, the DES accounts for this fact in the proposed. The baseline has an on-site (in the building) plant. So any pipe losses within the building are the same in both models. The DES has you take into account the losses to the building in the proposed, not within it.

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James Chueh
Jan 18 2012
LEEDuser Member
1141 Thumbs Up

LEED HC project with a basement-connected CUP building

We are doing a HC project that has two visually separate buildings, main clinic building and a CUP building, but these two buildings' basements are connected. We are thinking using DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. Guidance Performance Option 2 to obtain higher energy scores. The mechanical rooms and control room are in CUP building's above-grade floors, its basement is a part of the main building's clinical space.

However, we are not sure if we want to certify the CUP buildings. Are we allow to exclude CUP building from the LEED boundary, but still include its basement? Because it seems that in DES Guidance it allows CUP building not to be certified.

Please help, cheers.

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Emily Catacchio Sustainability Specialist, Wight and Company Feb 18 2012 Guest 9886 Thumbs Up

Generally, the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. Guidance does not require that you certify the building where the the mechanical rooms are. So I do not think this is a DES Guidance issue. However, to the connected basements may pose an MPR #2 issues. I do not have experience with a building which uses space, essentially, under another non-certified building (if I'm understanding you correctly). 

I would recommend contacting GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). to find out if the connected basement puts the project in danger of not meeting MPR#2 assuming you won't be certifying the CUP building. 

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Scott Bowman LEED Fellow, Integrated Design + Energy Advisors, LLC Feb 20 2012 LEEDuser Expert 10993 Thumbs Up

I think that Emily is right on with investigating the MPR. This seems more of a question of project boundary than DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity..

We recently were involved in a large project (which ultimately got Platinum) that had an adjacent parking ramp that housed the central plant for the building. That structure is not LEED certified, so we treated the project as being served by a DES. So having a division such as that can work. Note that we were fully modeling the plant and the plant was fully commissioned as part of the project (and was under v2.2 as well).

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Adam Targowski Owner ATsec
Aug 04 2011
Guest
2423 Thumbs Up

EA Cre 3 - DES commissioning

Does anyone know how to deal with CommissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. of District Energy SystemA central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. (DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity.)? The project which I'm working on is situated in a city which is supplied with heat by a large District Energy System. It's impossible to make a commissioning of the whole system. How can I comply with the requirements of EA Cre 3? Is it enough to submit official documents obtained from the heat generating plant and distribution system owner saying that DES was properly commissioned and maintained?

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Scott Bowman LEED Fellow, Integrated Design + Energy Advisors, LLC Dec 08 2011 LEEDuser Expert 10993 Thumbs Up

Adam;

Sorry, your post has only just come to my attention. We have not had to address this yet, but my reading of the August update to the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guideline seems to focus on three things; the size of the project, the age of the DES, and the percentage of the load the new building represents of the total capacity of the DES provider. Basically, they want to prevent a project from developing an external energy plant, and then call it a DES.

So, in your case it would seem that you have a plant over 3 years old, your building is probably bigger than 50k SF, and you are looking to gain some energy points under EAc1, which I agree would indicate a need for commissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. of the DES if you pursue EAc3.

Then this guide seems to give you two paths, and yours would most likely be the second, getting some information from your DES on their maintenance and operation practices. My guess is they have something they have to show, since they only sell BTUs, they would have to maximize efficiency to either enhance profit, or keep public utility costs down.

Let us know how it goes, you could be exploring new territory.

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Ghaith Moufarege
Dec 07 2010
LEEDuser Member
10175 Thumbs Up

EA Credit 3 - Threshold

The treatment of DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. guidance issued in Aug 2010 says the following:

"CommissioningThe process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements. of the district energy systems serving the building are required for larger buildings where the thermal energy supplied to the building exceeds a given percentage, or when the percentage of energy provided by the district plant to the building exceeds a given threshold"

Do any of you know what this percentage or threshold is ? In our case 8% of the output of the DES is supplied to the building we are working on. Does that mean the DES needs to be commissioned ?

Thanks for the help,

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Dec 08 2010 LEEDuser Moderator

George, the language you're quoting is from the Executive Summary of the document. Read further.

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COWI AS
Oct 14 2010
LEEDuser Member
1261 Thumbs Up

Very large complex DES

Hi

I'm trying to certify a building in Denmark which is connected to the local district heating system. This system delivers district heating to about 275.000 households, the plant is about 15 miles away and is run by a private company. We can't get detailed information about pressure loss in the pipes etc. Anyone knows how to adress this? As I read the new guidance on DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. we can only get 10 points for this model if we don't do it upstream which is kind of crazy;-) But why can't we only get 10 points for this building that saves more than 75% energy compared to the baseline?

Does anyone know when this DES will be unloaded for these very large complex DES?

Kind regards
Niels Varming

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Christopher Schaffner Principal & Founder, The Green Engineer, Inc. Oct 14 2010 LEEDuser Expert 9155 Thumbs Up

The logic for a points cap is that the DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. may not be very efficient.

In the old DES guidance, the plant efficiencies had to be included, so a project connected to a poorly performing plant might not any points. At least with this new guidance your project could get some credit.

What are the thermal losses on a 15 mile heating pipe? Why would you not want to consider a stand-alone system?

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COWI AS Oct 15 2010 LEEDuser Member 1261 Thumbs Up

Hi Christopher

Thank you for your reply.

The DESDistrict energy system: a central energy conversion plant and transmission and distribution system that provides thermal energy to a group of buildings (e.g., a central cooling plant on a university campus). It does not include central energy systems that provide only electricity. is very efficient. Compared to oil or gas there is a significant smaller CO2Carbon dioxide-outlet by using DES. The thermal losses of a large system of heating pipes are of course accounted for in this CO2-calculation. This solution is a lot cheaper to establish than a stand-alone system, and there is also a requirement i the danish building regulation that we should use district heating.

So environmental , economic and legislative issues have influenced the choice of district heating.

I think you need to understand that this is a very large system and not just a system covering a campus or something similar. Most of the city of Copenhagen (approx. population 1 million) is covered by district heating, so it is not a 15 mile heating pipe, but a network of heating pipes supplying all the households in the capital of Denmark.

So bottomline is that I have taken the most environmental friendly heating supply, I have designed a building that uses less than 25% of the baseline building, but I still can't get the maximum number of points.

Is the way to go a more detailed narrative about the danish district heating and attach this in Alternative Compliance.

Kind regards

Niels Varming

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Christopher Schaffner Principal & Founder The Green Engineer, Inc.
Aug 18 2010
LEEDuser Expert
9155 Thumbs Up

DES Guidance

One thing to look out for - while teams can now pick either Option 1 or Option 2, note that each options have point limitations. Under Option 1, projects can only earn a maximum of half the points available under Option 2.

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Eric Shamp Principal Ecotype Consulting
Aug 17 2010
LEEDuser Expert
1004 Thumbs Up

District PV Energy?

Would this guideline also apply to district renewable energy systems, i.e. a large PV array located on a campus?

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Aug 17 2010 LEEDuser Moderator

Yes. See the note under "Renewable Energy Energy sources that are not depleted by use. Examples include energy from the sun, wind, and small (low-impact) hydropower, plus geothermal energy and wave and tidal systems./ Green Power" on page 4 of the LEED DES guide.

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