Cost of the Prerequisite
Projects must not use CFC-based refrigerants (R-11 and R-12) or must commit to replacing existing equipment with new, non-CFC equipment.
Commercial production of R-11 and R-12 refrigerants stopped in 2010, so for new projects, or projects using new cooling equipment, compliance with the prerequisite will have no added costs.
For existing buildings with existing equipment or projects that use existing central plants, teams will need to check if CFC-based refrigerants are being used. If they are, LEED requires either installing CFC-free equipment, or commiting to phasing out CFC refrigerants through refrigerant conversion or equipment replacement within five years of “substantial completion” of your project.
This could be expensive depending on your project specifics. If the system is relatively new and not due for replacement, the cost could be hard to swallow. But replacement of systems that are older, less efficient, and more maintenance-intensive could be easily to justify due to the return on investment.
Cost of the Credit
The credit awards one point to projects utilizing low-impact refrigerants or those that calculate the environmental impact of the refrigerants being used.
Low-impact refrigerants include R-407c, R-410a, and R-134a, which are used in the majority of commercially available HVAC equipment. R-22 and R-123 are still in use in some units; R-123 especially in large chillers because it provides excellent operating efficiency, and the refrigerant state points and operating pressures are closely related to the water temperatures used in a water chiller.
To fill in the refrigerant impact calculator for credit documentation, you’ll need to know each refrigerant’s Ozone Depletion Potential (ODP) and Global Warming Potential (GWP). The calculator takes both values into account, along with the quantity of refrigerant used and the cooling effect produced.
Self-contained or packaged units with all refrigerant internal to the unit will calculate better than split system units, which can have long lengths of refrigerant pipe between the units. Similarly, even packaged units that have large amounts of refrigerant piping or that use inefficient piping layouts inside the equipment can fare poorly when input into the calculator. For this reason, it is best to perform the calculation for all the equipment specified in the design and to update the calculator when the equipment shop drawings are submitted.
It’s important to remember that different manufacturers use different refrigerants. For example, Trane and Carrier use different refrigerants in their respective centrifugal chillers. Smaller rooftop units and split systems generally use the same refrigerant regardless of manufacturer, but higher capacity and custom application rooftop units can vary the refrigerant based on cooling application and compressor type.
It is worth shopping around for small units to be able to compare pricing, efficiency, and refrigerant impact; however, small units are a commodity and there is limited ability for projects to be able to influence the specifications of equipment manufacturers. Larger equipment is generally manufactured from the ground up and there is more flexibility in selecting capacities and refrigerants to suit project requirements.
HVAC equipment costs are generally driven by more than just capacity, equipment type, and refrigerant. Demand, manufacturer capacity, quantity, schedule, contractor experience, and vendor relationship can all affect the cost of particular piece of equipment.
Therefore, consider the cost of this credit on a project-by-project basis, and remember to compare different types of equipment and their operating characteristics in the energy model.
Remember that if you change the refrigerant type as part of the construction submittal process, the energy model must also be updated.
EAp2/EAc2: Energy Performance