I believe it’s loud and clear: GWP alone does not measure a system’s lifetime emissions. When we choose a refrigerant, we must look at its Lifecycle Climate Performance (LCCP). LCCP is the sum of a refrigerant’s GWP rating and system-performance rating and is reported in carbon dioxide equivalency.
Most of the climate impact from HVAC systems is from electrical power usage over the system’s lifetime. Thus, a lower efficiency refrigerant, albeit with lower GWP, could actually increase CO2 equivalent emissions and lead to more global warming!*
Let’s show you an example model to compare lifetime CO2 equivalent emissions / LCCP for comparable R410A and R32 systems. This residential model took advantage of the improved efficiency of R32 for cooling and heat pumps across the US.
- The dark blue shaded region shows indirect emissions – caused by power plants that generate electricity needed to operate the system over its lifetime – the largest source of CO2 emissions.
- The light blue shaded area is direct emissions from leaks during operation (not always likely to occur) and the orange area indicates leaks that can occur during end of life at the time of decommissioning the equipment.
This big blue bar is the reason why the industry is moving towards decarbonization – moving away from the combustion of fossil fuels - and increasing system efficiency. Daikin has observed efficiency improvements of up to 12% with R-32 as compared to R-410A, which can help drive down energy consumption, and therefore CO2 emissions, over the life of a product. Driving this blue bar to a much smaller value has NOTHING to do with the GWP of refrigerants!
The light blue bar indicates direct emissions resulting from release of refrigerants to the atmosphere. The significant drop of 80% in emissions, a result of moving to R32 from R410A, is primarily due to the lower GWP and up to 40% charge reduction. Emissions can occur due to the energy used to produce the materials of construction as well, indicated by gray colored bars, but that’s relatively negligible
Don’t get caught with a refrigerant that doesn’t improve efficiency over R410A and certainly don’t use a refrigerant that has worse efficiency. Think about total lifetime emissions and choose a refrigerant like R32 that has excellent efficiency benefits. With improved efficiency and a lower GWP compared to R410A, R32’s a great choice for the sake of the planet as well as for reducing operating costs.
Author: Philip Johnston, GM, Low GWP Program Leader, Daikin Applied
*(Source: Zhang M., et al. 2011. “Life Cycle Climate Performance Model for Residential Heat Pump Systems.” AHRTI Report 09003-01)