Expert Advice on Green Buildings

Refrigerant Management: What's the Difference Between LEED EAp3 and EAc4?

 
Question:

Don asks: My understanding is R-22 is an HCFC (hydrochlorofluorocarbon) as opposed to a CFC (chlorofluorocarbon) based refrigerant, it’s already compliant with Energy and Atmosphere Prerequisite 3 – Fundamental Refrigerant Management. Is that correct for the current versions of LEED? NC, Core and Shell, etc?

Answer:

Hi Don, thanks for your question.

We’ll start out with a (very) brief description of the differences between the Energy & Atmosphere Fundamental Refrigerant Management prerequisite and the LEED EAc4 credit in the current prevalent USGBC LEED rating systems.

The Fundamental Refrigerant Management prerequisite in LEED rating systems for New Construction, Schools, and Core & Shell read identically, since they’re all part of the 2009 Building Design & Construction Reference Guide. The only difference in the 2009 Green Building Operation & Maintenance Reference Guide (EB: O&M Rating System) is that the prerequisite includes information with regard to a demonstrated phase-out plan of CFC-based refrigerants in place in the existing building. Finally, the prerequisite is identical to the LEED Interior Design and Construction Reference Guide (CI Rating System) except for some wording with regard to tenants.

So all that being said, how does the credit relate to R-22? Well as you said, R-22 is a hydrochlorofluorocarbon (HCFC) with an Ozone Depleting Potential (ODP) of 0.04 and a Global Warming Potential (GWP) of 1,780. So since it’s not a chlorofluorocarbon (CFC), the quick answer is that yes, it complies with prerequisite requirements.

But the answer isn’t quite so simple… In 1987, the Montreal Protocol established requirements that began the worldwide phase-out of ozone-depleting CFCs, which have ODP values up to the highest possible 1.0 and GWP values in excess of 4,600. In 1992, the protocol was amended to establish a schedule for the phase-out of HCFCs as well. And while HCFCs are less damaging than CFCs, they still contain ozone-destroying chlorine. This means that as of 2020 the production of new R-22 will be halted, making it a commodity for the numerous existing HVAC systems around the world that have been using it for the past 40 years. And while reclaimed R-22 will be available after the manufacturing phase-out, as of January 1, 2010 HVAC system manufacturers were prohibited from producing new equipment containing R-22 per the protocol. So, existing owners and suppliers aren’t really rushing to replace their existing R-22 systems yet, but the installation of new R-22 equipment is probably not the best recommendation (though pre-existing equipment manufactured before the January 2010 deadline is still being installed).

Now, when we get into the other refrigerant-related LEED credit, EAc4 – Enhanced Refrigerant Management, the use of R-22 can be a deal-breaker compared to hydrofluorocarbon (HFC) refrigerants such as 407C or 134a, both of which are R-22 replacements, have an ODP of 0 and GWPs of 1,700 and 1,320, respectively. So while the ODP of HCFCs is much smaller than that of the CFC-based refrigerants, it’s not negligible. And while the ozone-depleting potential of the HFCs is zero, the calculation for EAc4 takes global warming potential into account as well, and the refrigerants with 0 ODP sometimes cause more climate change than those with higher ODP.

So choosing a refrigerant based on both of these factors as well as performance (HFCs are slightly less efficient refrigerants than the HCFCs) is sometimes a balancing act.

Of course these calculations should be done early on in the decision-making process if the project is pursuing LEED certification so the appropriate products can be specified.

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Expert Advice and Comments

Ozone and refrigerant

How is the Ozone most effected?
Climate change or global warming or leakage of refrigerant to the atmosphere? or any other reason?
Thank you