This credit can be fairly difficult to understand at a glance. So let’s start by getting some common misconceptions out of the way.
One common misconception is that this credit specifies or prohibits a certain refrigerant type. That was true in early versions of LEED (and is still the case in the prerequisite, EAp3).
Another misconception is that this credit solely concerns refrigerants’ ozone-depleting and global-warming potentials (ODPOzone Depletion Potential (ODP) is a measure of ozone impact a chemical has relative to CFC-11 (trichlorofluoromethane), which has a ODP of 1. and GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. ), and that a refrigerant like R-410A automatically complies because it has low ODP and GWP numbers. But the credit requirements also include other variables, such as the ratio of coolant charge to cooling capacity for a given compressor unit, and this credit considers the life of the unit and the refrigerant leakage rateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608).. R-410A, for example, may be compliant in some scenarios but not in others.
To earn this credit, you’ll need to:
The credit is about reducing the environmental impact of refrigerants in space conditioning and large-scale refrigeration systems in project buildings. It deals with two environmental impacts of concern: depletion of the ozone layer, and greenhouse gas emissions. EAc4 is more comprehensive than EAp3: Fundamental Refrigerant Management, which only concerns the use of ozone-depleting CFCs in equipment.
All permanently installed HVAC&R equipment with more than 0.5 lbs of refrigerant—including chillers; unitary HVAC equipment (split and packaged); room and window air-conditioners; computer, data center, and telecom room cooling units; and commercial refrigeration equipment—is addressed by this credit.
The credit also addresses fire suppression systems that contain ozone-depleting substances, including CFCs, HCFCs, or halons. Halon production was banned in the U.S. in 1994, as it is many times more ozone-depleting than CFCs and HCFCs.
While ozone is an unwanted pollutant at ground level (it’s a key component of smog), in the upper atmosphere a sparse layer of ozone plays a critical role in filtering out harmful ultraviolet rays from sunlight.
The Montreal Protocol on Substances that Deplete the Ozone Layer—the world’s first global environmental protection treaty—prescribed a complete phase-out of CFC-based refrigerants by 1995, and of HCFCs by 2030 in developed countries. As a result, environmentally preferable refrigerants are becoming more widely available for new systems.
From an environmental perspective, the best way to earn this credit is to avoid the use of refrigerants altogether, by using either passive or evaporative cooling strategies, or with absorption chillers (see Related Products in the right column).
If neither of these is an option for your project, earning this credit will be more about the selection of mechanical equipment and associated refrigerants.
The best way to determine credit compliance is to run compliance calculations as soon as an HVAC system is proposed. Not all compressor units have to be in compliance individually; this credit calculation uses a weighted average based on cooling capacity (in gross ARI-rated ton). Leakage rates and coolant charge are as important as GWP and ODP factors in influencing credit calculations.
If your project already has designed an HVAC system and now wants to change the refrigerant to meet the credit, you will find that it may not be as simple as swapping out the coolant or the compressor unit for a more environmentally benign choice. Rather, your entire HVAC system may have to be resized to accommodate the different capacities and efficiencies of the newer units.
This is a relatively easy credit to obtain if your project has a centralized cooling plant, with a favorable “coolant charge to cooling capacity” ratio. But even for projects with smaller, more dispersed units, this credit should be achievable if you consider the credit requirements early.
Because requirements are based on the average refrigerant impact per ton of capacity, a low-performing system can be offset by high-performing systems, or a building with a large amount of heat pumps can still comply if the cooling capacity of the heat pumps is high enough.
That said, there are some project types where meeting these requirements will be more difficult. Supermarkets and restaurants with high volumes of commercial refrigerators need to carefully plan how to design HVAC&R systems to earn the credit.
Ironically, some of the refrigerants that can help earn this credit are used in systems with poorer energy efficiency, resulting in increased greenhouse gas emissions. (CFCs were super-efficient, they just happened to be toxic and destroyed the ozone layer.) The life cycle of operational efficiency and refrigerant performance is not covered by this credit, but leakage and direct environmental impact are. Any loss of efficiency is a trade-off that has to be accounted for in EAc1.
For new construction projects, the short answer is that you don’t have to worry about it: only the default leakage rate of 2% is accepted in the credit calculations.
All HVAC&R equipment that will serve the project building should be included in the calculations.
Any permanently installed piece of equipment containing greater than 0.5 lbs. of refrigerant and included in the project scope should be included in calculations.
The system capacity should be based on the outdoor units, while all parts of the system including outdoor, indoor units, branch selectors and piping should be counted for the total refrigerant charge.
The system capacity should be based on the outdoor units. If you have multiple interior devices connected to one outdoor unit, the cooling capacity should be for the outdoor unit, but the refrigerant charge must include all interior devices.
While a phase-out is allowed in the prerequisite, EAc4 is like other credits where the credit should be achieved as part of the LEED scope of work. The work should be completed during construction.
The project team must use equipment life values from the 2007 ASHRAE Applications Handbook as listed in the LEED Reference Guide. For equipment not listed in the ASHRAE Applications Handbook, the equipment life must be assumed to be 15 years—no estimates are allowed. An alternative equipment life may only be used if a manufacturer’s guarantee and equivalent long-term service contract can be provided.
Portable fire extinguishers are not required to be included in EAp3 or EAc4.
If your project has no cooling system or uses a system without refrigerants, you can achieve the credit through Option 1 (“do not use refrigerants”). Document your credit compliance path with appropriate supporting documents by completing the credit form and providing cut sheets or other confirmation of the system type.
Earning EAp2 and drawing up energy efficiency goals can help to determine your project’s cooling strategy as it relates to energy consumption. This exercise may help you prioritize energy performance versus refrigerant selection, when applicable.
If your building uses only natural ventilation, it complies with Option 1 and the credit is automatically earned without your having to submit any calculations.
To comply with Option 2, you’ll need to calculate the weighted impact of the following characteristics of all refrigerants used in your project:
The calculated weighted average for the project should not exceed 100:
(LCGWP + LCODP x 105 ≤ 100). See the credit language and LEED Online for additional detail on the formulas behind that calculation.
All permanently installed HVAC&R equipment with more than 0.5 lbs of refrigerant—including chillers; unitary HVAC equipment (split and packaged); room and window air-conditioners; computer, data center, and telecom room cooling units; and commercial refrigeration equipment—is addressed by this credit.
Any fire suppression systems must contain no halons, CFCs, or HCFCs. This requirement is separate from the refrigerant requirements and is not included in refrigerant compliance calculations.
EPA’s SNAP program (see Resources) lists a range of alternatives to ODP substances. Review these alternatives and confirm the applicability to your system type. Consider using these to help meet the credit requirements.
Identify suitable systems in collaboration with the project owner and facilities management. Common alternatives for fire suppression systems usually are based on carbon dioxide, water, or dry chemicals (ABC or BC type powders).
If your project building is connected to a district chilled-water system, you have to include all the chillers in that system in the calculations, even if they are outside your project’s scope or control.
Even one piece of equipment can tip your calculations to compliance or noncompliance. Use the calculator in the LEED Online credit form to run calculations from the beginning of HVAC system selection (note that your project has to be registered through LEED Online to download those forms). This gives a sense of how far from compliance a system may be; teams then get a better idea of how significant a change may be required. Note that annual leakage and end-of-life refrigerant loss rates are set to defaults but can be edited if needed.
Consider incorporating passive cooling strategies in your design to reduce or eliminate the need for mechanical equipment that uses refrigerant.
Your mechanical engineer can investigate alternative mechanical systems that use natural refrigerants such as water, carbon dioxide, or ammonia.
There may be first-cost and operating-cost differentials for alternative refrigerants, so careful research is required.
Operations and maintenance staff need to be on board if you select a system that is unconventional or requires a new maintenance protocol. It is best to have operations and maintenance staff participate in MEP meetings regardless of system type.
Check the table of commonly used refrigerants in the LEED Reference Guide. Identify those that have lower values of ozone-depleting or global-warming potential (ODP or GWP, respectively).
Consult equipment cut sheets for refrigerant name and capacity, leakage rate, and end-of-life loss—or call the manufacturer directly for this information. A higher leakage rate implies a higher environmental impact as well as a higher recharging cost for the project.
R-410A is a common replacement for R-22 as it is more environmentally benign, with similar performance. It can help with compliance, depending on the equipment variables of “coolant charge to cooling capacity” ratio.
Because mechanical conditioning and ventilation represents a large portion of your building’s energy use, equipment—and consequently refrigerant—selection will affect your energy consumption and costs.
System choice is crucial to earning this credit. Centralized systems are likely to be more efficient and to make compliance easier. Equipment for decentralized systems has been slower to convert to more benign refrigerants, so compliance can be more difficult.
Check multiple equipment manufacturers to see what refrigerants they specify for their equipment. There may be a variety of system types that will help meet the credit requirements in a variety of ways.
Packaged terminal air conditioners (PTACs) typically use refrigerants with a high environmental impact. These units may make meeting the credit requirements more challenging, especially for hotels and multifamily residential projects, which tend to use them. The industry has been moving toward upgrading these refrigerants, so check with manufacturers for recent upgrades to their products. Newer refrigerants may help credit calculations.
Common split systems use varying refrigerants, in a range of quantities and leakage rates. These systems can have a hard time meeting the threshold for credit compliance because their leakage rates are high. Check your specifications early in the design stage and investigate these products if you’re thinking of using split systems.
The default leakage rate used in the credit form calculator is 2%, and the end-of-life refrigerant loss value should be 10%. If your project has equipment with different leakage rates, those values can be used instead.
There are trade-offs with all refrigerants. R-410A, for example, has a lower refrigerant charge, defined as the ratio of refrigerant to gross cooling capacity, but it uses more energy which may increase operating energy costs and will have a negative impact on your compliance with EAc1: Optimize Energy Performance, and total energy use reduction for the project.
All refrigerants involve tradeoffs. HFCs, for example, don’t contain chlorine and have zero ozone depletion potential, but they have significant global warming impact. HFCs are also less efficient than conventional, chlorine-based refrigerants, which are the most damaging to the ozone layer. Ammonia is highly efficient and ozone safe, but it can be hazardous to human health if released in large quantities.
Note that this credit requires the weighted average of all refrigerants to be less than 100, even if, individually, some are higher. That’s why it’s important to run the calculations several times until the final equipment is selected for your project.
Complete credit calculations based on the finalized mechanical system design.
The refrigerant charge is typically calculated automatically in the LEED Online credit form. It is the relationship between how much refrigerant is needed (in pounds) and the cooling capacity (in gross ARI-rated tons) of the equipment.
Specifying high-quality equipment with a long lifespan can reduce environmental impacts, since most leakage occurs during installation and decommissioning. For information about the service life of different types of HVAC equipment, refer to the 2007 ASHRAE Applications Handbook—HVAC Applications. (See Resources.)
Complete your documentation on LEED Online. Input the product make and model. If not using the defaults provided by LEED Online, input the refrigerant charge, leakage rate, and end-of-life leakage based on the equipment data.
Organize documentation of equipment specs and the maintenance requirements intended to minimize refrigerant leakage and transfer this information to the owner’s facility managers.
Retain the manufacturer’s cut sheets showing the leakage rate of each piece of equipment.
Provide refrigerant leak-detection equipment in the same location as your HVAC&R equipment.
Put in place a program of preventive maintenance for the equipment end-of-life management.
Retain manufacturers’ data and design specifications for your fire suppression system, confirming that it meets the credit requirements.
Refrigerants are not harmful to the atmosphere until they are released into it. Comply with best-practice refrigerant management regulations to minimize leakage rates during operation and when installing or removing new equipment.
Excerpted from LEED 2009 for New Construction and Major Renovations
To reduce ozone depletion and support early compliance with the Montreal Protocol while minimizing direct contributions to climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008)
2.The increase in global average temperatures being caused by a buildup of CO2 and other greenhouse gases in the atmosphere. This temperature change is leading to changes in circulation patterns in the air and in the oceans, which are affecting climates differently in different places. Among the predicted effects are a significant cooling in Western Europe due to changes in the jet stream, and rising sea levels due to the melting of polar ice and glaciers..
Do not use refrigerants.
Select refrigerants and heating, ventilating, air conditioning and refrigeration (HVAC&R) that minimize or eliminate the emission of compounds that contribute to ozone depletion and global climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008)
2.The increase in global average temperatures being caused by a buildup of CO2 and other greenhouse gases in the atmosphere. This temperature change is leading to changes in circulation patterns in the air and in the oceans, which are affecting climates differently in different places. Among the predicted effects are a significant cooling in Western Europe due to changes in the jet stream, and rising sea levels due to the melting of polar ice and glaciers.. The base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. HVAC&R equipment must comply with the following formula, which sets a maximum threshold for the combined contributions to ozone depletion and global warming potential:
Life: Equipment Life (10 years; default based on equipment type, unless otherwise demonstrated)
For multiple types of equipment, a weighted average of all base building HVAC&R equipment must be calculated using the following formula:
Small HVAC units (defined as containing less than 0.5 pounds of refrigerant) and other equipment, such as standard refrigerators, small water coolers and any other cooling equipmentThe equipment used for cooling room air in a building for human comfort. that contains less than 0.5 pounds of refrigerant, are not considered part of the base building system and are not subject to the requirements of this credit.
Do not operate or install fire suppression systems that contain ozone-depleting substances such as CFCsChlorofluorocarbons (CFCs) are a compound of carbon, hydrogen, chlorine and fluorine, once commonly used in refrigeration, that depletes the stratospheric ozone layer., hydrochlorofluorocarbons (HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons.) or halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer..
Design and operate the facility without mechanical cooling and refrigeration equipment. Where mechanical cooling is used, utilize base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. HVAC&R systems for the refrigeration cycle that minimize direct impact on ozone depletion and global climate change1. Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). (U.S. Environmental Protection Agency, 2008)
2.The increase in global average temperatures being caused by a buildup of CO2 and other greenhouse gases in the atmosphere. This temperature change is leading to changes in circulation patterns in the air and in the oceans, which are affecting climates differently in different places. Among the predicted effects are a significant cooling in Western Europe due to changes in the jet stream, and rising sea levels due to the melting of polar ice and glaciers.. Select HVAC&R equipment with reduced refrigerant charge and increased equipment life. Maintain equipment to prevent leakage of refrigerant to the atmosphere. Use fire suppression systems that do not contain HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons. or halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer..
Program to evaluate and regulate substitutes for the ozone-depleting chemicals that are being phased out under the Clean Air Act.
To determine the service life of a piece of HVAC equipment.
Required reference document for DES systems in LEED energy credits.
The table ranks commonly used refrigerants based on their life in the atmosphere. Longer-lived compounds typically have higher global warming potential (GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. ).
Article describing the movement towards Halon free chemicals with a comparative analysis.
Greenhouse Effect explained and illustrated.
Article explaining the ozone layer problem.
If you need to complete a CFC phase-out plan for LEED compliance, here's a sample.
This sample equipment spec sheet highlights the data points and calculations you'll need to use to determine the refrigerant charge (Rc) input required for LEED documentation.
Use this refrigerant management calculator to track and document your compliance with EAp3 and EAc4. You may also use the LEED Online credit form to document compliance, but that form has a finite number of rows, whereas this one can be expanded indefinitely. If you choose to use this calculator, add a narrative in LEED Online about using a supplemental calculator to complete calculations, and upload the document on LEED Online.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
We have a project where a Walk-in refrigerator and freezer are planned. These rooms will be equiped with dedicated split-system charged with R404.
It seems that the Rc will be above the 5lb/tons, mostly because of the distance between the freezer rooms and the mechanical rooms.
In the LEED-Canada template, there a limit of 5lb/ton. Is this an ARI requirement or could we just propose an alternate calculation to demonstrate compliance.
All the other systems are compliant with the requirements.
Earning this credit is based on the average refrigerant impact per ton, for all HVACR equipment in the project scope. It is possible that you can still comply if one type of equipment exceeds the maximum charge. But if you have entered all your equipment into the credit form and still do not comply, you may be out of luck.
We are using the EAc4 calculator published by Trane for a similar scenario. As it uses the same default values and formulae, we're confident it will be accepted in lieu of the LEED Canada template that doesn't accept an input greater than 5lb/ton.
For refrigeration equipment(Freezers/coolers etc etc) what is the life expectancy that should be put into the EAC4 template? The equipment in question are freezers and coolers that are to be attached to Indoor Water-Cooled Remote condensing units. There is no manufacturing data as the equipment is custom made.
I haven't documented such systems in my own projects, but you could try using the 20 year figure for reciprocating and scroll compressors if they are present in your system.
thanks for the quick reply...I managed to find it ..it is 23 years default value for screw chillers
The link for explaning Greenhouse Effect explained and illustrated under publications is not working.
Thanks for letting us know, David! I've replaced that dead link on the Resources tab with a link to a fun, interactive tutorial from Oxford U.
I'm trying to fill the EAc4 form, but I don't understand about HVAC&R at all. I'm not too sure what is N, Q and Rc column meaning. Please correct me if I'm wrong.
N = number of outdoor HVAC unit
Q = the weigh of the outdoor HVAC unit
Rc = the weigh of refrigerant inside the piping system.
Are those correct?
In addition, I also found difficulties in filling the Rc column. In the form, Rc unit is in lb/ton, but as I look into the manufacturers data, the Rc is provided in kg. How can I deal with this? Please help, because our HVAC engineers are also not familiar with refrigerant impact calculation.
N is the number of units matching that description
Q is the capacity of each unit in "tons" (1 ton = 12,000 btuA unit of energy consumed by or delivered to a building. A Btu is an acronym for British thermal unit and is defined as the amount of energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit, at normal atmospheric pressure. Energy consumption is expressed in Btu to allow for consumption comparisons among fuels that are measured in different units./hr)
Rc is the weight per ton of the refrigerant.
You may need to convert from kg to lb and from kW to tons. To calculate the Rc, you can divide the total refrigerant charge weight by the unit capacity. For example, a 25 ton AC unit with 23 lb of R-410A will have an Rc of 0.92 lb/ton.
Should we include the manufacturers default information on refrigerant or should we use the actual refrigeration charged installed even though these are not installed and confirmed after installation?
You will want to use the actual intended refrigerant charge as shown on either mechanical schedules on drawings or on a project-specific submittal. General info from brochures or other material will not be sufficient.
Then this should be a construction credit, because this most of the time depends on the contractor. We as engineers specify the type of equipment and refrigerant but not the actual charge. We have submitted this credit previously with the manufacturer values and they have approved it but I guess it really depends on the reviewer.
Little question :
What does the acronym of ARI mean in the credit guidance?
Hi Cédric. I think it stands for Air-Conditioning and Refrigeration Institute.
"ARI rated cooling capacity".
I have a split units that their Rc is above 5 mentioned in the Reference Guide, but fortunately my average refrigerant atmospheric impact is lower than 100 (according to use efficient centrifugal chillers). Now can I get this credit or not?
If the calculations show that your impact is lower than 100, you can earn the credit. Typically, its the use of split systems as the only HVAC system that makes the credit difficult to achieve.
I have about sixty-five split systems in two apartment buildings using R-410a. The factor that is keeping me from meeting this credit's requirements seems to be Rc (lb/ton). Since these are small systems, their Rc runs from 1.9 to 3.5, but most are about 2.8. It looks like that makes compliance impossible.
Has anybody, anywhere, ever made this credit with small split systems? Or am I just done for?
You will probably not earn the credit with split systems. Hopefully your system selection is helping you save energy and earn points under the energy performance credit.
Hello, I have a few questions regarding how to demonstrate the amount of refrigerant charge. The questions are as below.
We are preparing design phase review. According to the load calcualtion, we ordered mechanical equipments.
1) should product catalogs or brochures be submitted? In my LEED project, some building mechanical equipments were made to order. Threfore, there is no product catalog except few mechanical equipment like chillers, heat pumps. But, we have documents that indicate some information such as refrigerants charge, model number, refrigerant type from our manufacturer.
I am just wonderign if this document would be helpful for earning this credit.
Thank you for your help in solving this problem.
Any kind of documentation from the manufacturer should be adequate. It doesn't need to be a catalog or brochure.
I have two questions regarding a district cooling system to be used in one of our projects:
1- Can we use 0.51% value for Refrigerant leakage rateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608). and 2% for end of life refrigerant if the district cooling provider's studies clearly show such numbers (it seems to me this is the case although I've recently heard this was not possible anymore)?
2 - The diversity factor of the district cooling provider is 67%. This means that even though around 100MW (28,400 tons) of cooling capacity is installed, they sell approximately 150MW of cooling capacity to their customers. When calculating the refrigerant charge, should we include the diversity factor ? This would seem logical as the district cooling system is equivalent to the installations of numerous systems totaling a 150MW cooling capacity (hence the same quantity refrigerant for a larger amount of cooling capacity).
Many thanks for your help!
For #1 - the NC reference guide was revised several years ago to not allow project teams to use alternate leakage rates. In my personal opinion, the change targeted manufacturer's claims about new equipment. EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems., on the other hand, requires you to use actual leakage rates. I would first check if your project can comply with the credit using default leakage rates. If so, great. If the project doesn't earn the credit,you could try checking the box for "Alternative Compliance" and provide a set of calculations with the measured leakage rate. I've never tried this, but it might work if you provide very good documentation about the leakage history.
For #2, you should use the installed capacity of the actual chilling equipment - i.e. 100 MW.
And in general, be sure to check the version of the District Energy guidelines that were in effect at the time the project was registered.
The project we are working on will have old refrigeration equipments moved from other place. Do we need to calculate these equipments since they are not new purchased and the refrigerant is 0.5~1.5 lb? If yes, should the Installation Date be New or Existing?
Thanks for any suggestion.
James, you should include them. I would use the existing date for the installation date.
We have a project that has many commercial refrigeration equipment such as walk-in coolers and feezers in commercial kitchens. What is the ARI test standard (rating conditions) for defining the ARI rated cooling/refrigeration capacity in the credit calculation?
AHRI publishes a number of standards that could apply to the equipment in your project. I would review the list here http://www.ahrinet.org/search+standards.aspx and then check with the equipment vendor for the project to see which standard would apply to your specific equipment.
THE AHRI link above seems to be broken.
Here's an updated version: http://www.ahrinet.org/site/686/Standards/HVACR-Industry-Standards/Searc...
I am working on an addition to an existing building, the addition is attempting certification. The exsting building and the chiller plant do comply with EAp3, but, 2 chillers are HCFC-22 and raise the ARI to above 100. In order to comply with EAc4 the 2 chillers will have to be changed over to R-407c or be replaced.
Question is, will it be required to be retrofitted or replaced before construction is completed or can it be completed within a 5-year timeline?
Thanks for your help.
The retrofit/replacement should be done before construction is completed. While a phase-out is allowed in the prerequisite, EAc4 is like other credits where the credit should be achieved as part of the LEED scope of work.
Our system has 2 different refrigerant types. One type in the compressor and another type in the refrigeration circuit. Do we take into account both refrigerants or only the refrigerant in the compressor? If we need to take both refrigerants into account, how do we calculate this?
You must account for both types of refrigerant. In the calculations for this system, I think you will need to calculate the LCGWP and LCODP for each refrigerant., and then add those numbers to get the system LCGWP and LCODP. For example, if the total refrigerant charge is 2 lbs/ton, and the individual charges are 1.2 lbs/ton of Refrigerant X and 0.8 lbs/ton of Refrigerant Y, the LCGWP/LCODP of Refrigerant X should be calculated with the appropriate properties of Refrigerant X and Rc = 1.2.
This approach makes sense to me, but I haven't yet had to document a multiple-refrigerant system like this for LEED. If anyone else has, please chime in.
Has anyone calculated or have access to the R 404A maximum refrigerant charge as provided for some other refrigerants in Table 2 on Page 310 of the BD+C Reference Guide?
Cassidy, this is pretty simple to do. You can use the Refrigerant Management Calculator available here on LEED User under "Documentation Toolkit" for this credit to check the compliance for a given 404a charge, or you can use the ODPOzone Depletion Potential (ODP) is a measure of ozone impact a chemical has relative to CFC-11 (trichlorofluoromethane), which has a ODP of 1. and GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. values from the reference guide and solve the equation for Rc.
I got information about two of my cooling machines for a large supermarket. They have carbon dioxide as refrigerant. The actual cooling capacity is 120 kW per machine (34.12 tons of refrigeration) and 200 kg CO2Carbon dioxide (440.92 pounds) per machine. If I divide; 440.92/34.12 I get 12.92. Rc is only allowed to be between 0.5 and 5. In the calculator you mentioned, CO2 is not even in it. Any tips on why there is a max limit for Rc? What am I not understanding?
Which tonnage should be used when using refrigerant calculator while considering a chiller plant serving a static ice thermal storage system? When chillers are in Ice Making Mode producing 24F fluid; chiller capacity is substantially reduced as compared to Chiller Mode when chiller is producing 42F fluid. For example a 100 ton chiller at 42F discharge temp may produce 65 tons when producing 24F fluid. I am thinking a pro-rated calculation may be appropriate based on run hours per day or week. Your thoughts and comments please and thank you.
My guess is that the LEED reviewer will require the calculation be performed with the worst case condition (this ensures the mechanical system meet the credit requirement through all modes of operation) - similar to ventilation calculations.
We've tried and cannot get any info from GE other than they use R-134A refrigerant. Can anyone tell me from the valumes of these refrigerators normally for residential use that they might use less than 1/2 lb of refrigerant? Thanks.
Hi Waylon. Don't worry about those refrigerators. The credit language excludes "standard refrigerators" (residential type) regardless of exactly how much refrigerant they contain.
It is used in a project two HVAC systems (Split) in two areas of approximately 22.82 square feet, the total project area measures 27,857 square feet. The air conditioning equipment work with 1 and 1.5 tonnes at 2.18 and 2.94 pounds per ton respectively, these values do not get to complete the credit. Other projects use more than two of these equipments with equipment of chilled water system and I have been able to meet the credit. I think the impact on this second project is bigger than the first that does not meet the credit because more equipment are used. Can i meet the credit highlighting that only use 2 equipment in a small area compared to the whole project?
Lorena, I am not aware of an exception for projects with only a small amount of air-conditioned space. My only thought would be that there may be an alternate location available for the outdoor portion of the split systems, which would shorten the run between the indoor and outdoor units and possibly lower the required refrigerant charge.
In the form it was mentioned "Provide supporting documentation for non-default Life value(s) in Table. Refrigerant Impact Calculation such as a manufacturers' life guarantee and equivalent long term service contract"
I assume if I am usig life values mentioned in the LEED handbook so nothing is non-default value.but what is meant by the other part "Refrigerant Impact Calculation such as a manufacturers' life guarantee and equivalent long term service contract"
Tarek - You should request that the LEED Online form be upgraded to v4. The upload document item is removed from the v4 document, and you should be able to complete it.
I'm using the Version 4.0 of the form, and I still get the upload document item. I am using default Life values. Should I just upload a one sentence narrative saying we are using default life values? Thank you.
The project we're working on will be cooled with centrifugal chillers. The Mechanical Engineer is suggesting installing a "Reserve refrigerant box", which is a cylinder containing the same refrigerant as the one of the chillers.
This box is piped to the chillers, and will serve as an "replenishment supply" in case there is any leakage from the chillers.
Our query is:
Do you think we should include this additional "reserve" refrigerants in this credit calculations?
George, I would not consider the reserve refrigerant part of the required equipment charge, so I wouldn't include it in your calculations. The intent of the credit is to reward selection of equipment with efficient use of refrigerant.
Having built a cafeteria at a local University we are having trouble getting the Q (tons ) for some of the refrigerated display equipment. Has anybody had luck getting this information for True Mfg. Models TSSU-48-12, TSSU-60-10, TPP 44,
TAC 48, G4SM-23PT. We have contacted the MFG.s engineering dept and they have indicated they do not have this info. We do have the refrigerant charge on some of this equipment but need the tons to calc the total. Thanks any help greatly appreciated
Hello and thank you for your inquiry. Please see the answers to your question below:
MODEL / REFRIGERANT / COOLING RATINGS (BTUH) / HEAT OF REJECTION (BTUH) / TONS COOLING
TSSU-48-12 / R134a / 2070 / 3105 / 0.26
TSSU-60-10 / R134A / 2070 / 3105 / 0.26
TPP-44 / R134A / 2070 / 3105 / 0.26
TAC-48 / R404A / 9350 / 14025 / 1.17
G4SM-23PT / R134A / 2601 / 3902 / 0.33
Please let me know if you have any other questions
Thanks for the information. Will you also have the refrigerant mass and cooling capacity for the True Mfg. model T-24-GCA General Contractor (GC) manages, coordinates, and oversees building construction; may perform some construction tasks; and is responsible for hiring and managing subcontractors. -S? We got the refrigerant which is R404A but we are having difficulty getting the rest of the information we need to get the Rc.
Do the requirements apply to portable fire extinguishers or only permanently installed building-wide fire suppression systems?
Fire-suppression systems and extinguishers are referred to as separate things in the glossary entry for "halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer.," so it make sense that USGBC did not mean to include extinguishers in the scope of EAc4.
Hi everyone, I had already considered that portable fire extinguishers were excluded from the credit requirements, and today I had a response from a 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). representative that resolves the question officially:
Thank you for contacting the Green Building Certification Institute. Portable fire extinguishers are not required to be included in EAc4. The project team should ensure the fire suppression systems do not contain CFCsChlorofluorocarbons (CFCs) are a compound of carbon, hydrogen, chlorine and fluorine, once commonly used in refrigeration, that depletes the stratospheric ozone layer., HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons. or halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer.".
I wanted to share the resolution with everyone. Cheers!
In our project a absorption chiller will be used to cover part of the cooling load. The chiller will run on lithium bromide / water solution. In this case, water is the refrigerant.
Water is a natural refrigerant with GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. , but my feeling says in the LEED Online form GWP and ODPOzone Depletion Potential (ODP) is a measure of ozone impact a chemical has relative to CFC-11 (trichlorofluoromethane), which has a ODP of 1. should be set to 0. As far as I know the water content in the atmosphere depends on temperature mainly and not on water vapour released by humans.
Any hints or comments?
Wow--it wouldn't have occurred to me that water would have to be listed as a refrigerant with its own GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. . I think that you're safe just omitting that--it's generally assumed that absorption chillers don't use climate-changing refrigerants. I haven't encountered this question before, though--anyone else have experience with this?
I just wanted to double check that the VRF system lifetime is 15 years (considered a packaged AC). Is this true?
That's how I would interpret it.
I'm currently working on a LEED NC project on a central university library projects. While the HVAC centralized cooling unist comply with the requirement, a question has arisen about tenant equipment.
On the first floor, there will be comercial spaces leased for supermarket and general retailers. The supermarket include high volume (both in power and refrigerant amount) of commercial refrigeration units.
Should we include these, while the units are built and managed by the tenant?
Yes, I believe they would need to be included. If they are new, they should comply.
It seems to me that an unintended consequence of selecting a high efficiency water cooled centrifugal chiller ( both R-123 and R-134a) is the greater difficulty keeping impact per ton below 100 needed to achieve EAc4. I believe the reason is as the chiller manufacturers push their compressor/condenser/evaporator combinations to achieve high energy efficiency(low kw/ton); they find the need to add more and more heat exchanger surface. Along with heat increased heat exchanger surface comes more refrigerant. I have seen this play out with chillers from two major MFR. using two different refrigerants. Has anyone else had any experience with this phenomenon??
James, I agree that this is a factor.
A followup to my original question. I have found at least one major manufacturer (T) that was able to meet BOTH IPLV - 0.36 AND have a calulated EA credit 4 of less than 100. So it is possible, I just needed to apply a little more pressure to Mfr. Rep. Maybe someday the Chiller Mfrs. will open up their chiller selection software so that Engineers can make optimized chiller selections to meet each projects needs. A guy could dream!!!........
Is the tonnage requirement for the credit supposed to include compressor capacity only or can additional capacity from energy recovery devices be included in the tonnage?
Rebekah, I believe tonnage would include the whole system capacity.
Scenario: Campus new construction projects which are connecting to an existing central plant for heating and cooling. The reference guide and DES guideline are clear that you must consider the refrigerant in the central plant (or District Energy System) when doing the calculation. One of the variables in the EAc4 calculation is service Life of equipment. These values are provided for new equipment by the ref guide and ASHRAE.
Question: For the existing central plant equipment, should the service life be the full rated service life as published by ASHRAE or a prorated life accounting for the current age of the equipment (since it is not new)?
The 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). responded to my question and said that I should use the Reference Guide and ASHRAE values and not the actual age of the equipment. Wanted to share this information with everyone.
Where should I get the "gross ARI rated cooling capacity" for air to water heat pumps ? This is not covered by ARI 550/590 which usually applies to chillers. On the technical data sheets, I found the "nominal cooling capaciy" following Eurovent standard.
Do you think I can use this value ?
I think the nominal cooling capacity is close enough for this calculation.
Here's a stumper for y'all.
A "heat pipe" uses refrigerant migration (without compressors) between two coils for heat recovery. If I am using a heat pipe system, do I include that refrigerant charge in my calc for EAc4? If I do, how do I determine the tonnage?
There doesn't seem to be a lot of practical, usable numbers available for this technology. I'll let anyone else jump in here, I have no experience with heat pipe.
I'd say if the refrigerant is part of the HVAC&R equipment then it should be included in the credit calc. I see one company uses de-ionized water.
Regarding tonnage, I thought this was a load calculation based on climate, internal loads, and building envelople. A ton of cooling is equal to a ton of cooling, regardless of the equipment doing it. If a room needs 10 tons of cooling then that's the size of the heat pipe system specified.
The type of heat pipe, ambient temp, and orientation will affect how much energy it can transfer. I think it's up to the manufacturer to tell you a tonnage. And you may need to do a watts to ton conversion.
Interesting links I found. Now I know a little more about heat pipes.
Clean agent fire suppressant materials have no bearing on the Life Cycle Ozone Depletion calculation as they are not used as refrigerants. However, there is a statement in the Enhanced Refrigeration Management document from the LEED Reference Guide that in order to achieve the credit, fire suppression systems must avoid the use of halonsHalons are substances, used in fire-suppression systems and fire extinguishers, that deplete the stratospheric ozone layer., CFCsChlorofluorocarbons (CFCs) are a compound of carbon, hydrogen, chlorine and fluorine, once commonly used in refrigeration, that depletes the stratospheric ozone layer., and HCFCsHydrochlorofluorocarbons (HCFCs) are refrigerants that cause significantly less depletion of the stratospheric ozone layer than chlorofluorocarbons..
Our project, a massive Mission Critical Facility, is currently planning on using FM-200 (HFC-227ea) which is a heptafluoropropane, and not listed as a Halon, CFC or HCFC.
Has this Clean Agent Fire Suppression been approved for usage and do you anticipate any problems in our approach in utilizing it?
The reference product (HFC-227ea) does have a Global Warming Potential of GWPGlobal Warming Potential (GWP) is a measure of substances’ ability to absorb heat and warm the atmosphere relative to carbon dioxide, which has a GWP of 1, over a given time period. =3,660, but likely unrelated to his decision.
Any help would be awesome!
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