Global warming is a pressing concern that affects us all, but for professionals in the HVAC industry, understanding the intricacies of Global Warming Potentials (GWPs) is crucial. This blog post examines GWP, how it is calculated, and highlights why it matters for anyone involved in commercial HVAC systems. Stick around to learn how your work can contribute to a more sustainable future.
What Are Global Warming Potentials (GWPs) and Why They Matter
Global Warming Potentials measure how much heat a greenhouse gas traps in the atmosphere. The higher the GWP, the more warming a gas causes. Moreover, Carbon Dioxide (CO2) is used as the reference point for determining GWP, thereby giving the gas a GWP of 1. As the EPA puts it, GWPs are “a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO2).”
Given the HVAC industry’s reliance on refrigerants — many of which are potent greenhouse gases (many of which are being phased out) — understanding GWPs is crucial and helps us prioritize which gases to phase out. A prominent example we’ve discussed is hydrofluorocarbons (HFCs), which typically have high GWPs, making them prime targets for replacement with more sustainable alternatives.
The fight against climate change depends on reducing emissions with high GWPs. By switching to lower-GWP refrigerants, the HVAC industry can make a significant impact.
How Are GWPs Calculated?
The GWP of a gas is calculated over a specific time horizon, usually over the course of 100 years. The longer the period, the more accurate the assessment. The calculation involves complex formulas, but we’ll break it down simply here.
First, as previously noted, scientists compare the gas in question to carbon dioxide (CO2), which has a GWP of 1. They measure how much energy is absorbed by the gas and how long it stays in the atmosphere. For reference, Methane (CH4) stays in the atmosphere for about 10 years; Nitrous Oxide (N2O), which has 273x the GWP of CO2, lasts for more than 100 years!
Second, they use this data to calculate the “radiative efficiency” — aka the difference in ability to absorb energy — of the gas. The final GWP is then determined by comparing this efficiency to that of CO2.
Why Should the HVAC Industry Care About GWP?
The commercial HVAC industry plays a pivotal role in climate action. HVAC systems often use refrigerants with high GWPs (think R-410A), meaning they have a considerable environmental impact. Switching to refrigerants with lower GWPs can reduce this impact significantly — and soon enough, higher-offending facilities won’t have a choice.
Regulations are increasingly targeting high-GWP refrigerants. In particular, facility managers should look to the AIM Act and Local Law 97 to tackle their GWP problem. The phasedown of HFCs like R-410A (a GWP of 2,088) and R-404A (a GWP of 3,922) began on January 1, 2022, as such refrigerants are known to be harmful to the ozone layer and have high GWP. Per ACHR News, 2022 saw a 10% reduction of said refrigerants, while 2024 aims for a 60% cut by the EPA. Thus, future-proofing your systems by adopting low-GWP alternatives can save you from costly upgrades down the line.
The Role of Refrigerants in HVAC Systems
Refrigerants play a pivotal role in the operation of HVAC systems. They are substances used in refrigeration cycles to absorb heat and provide cooling. The working mechanism of refrigerants involves phase changes; they turn from liquid to gas to absorb heat and then back to liquid to release it, effectively cooling the air inside buildings or vehicles.
However, not all refrigerants are created equal. Traditional refrigerants like Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs), and Hydrofluorocarbons (HFCs) have been found to be harmful to the ozone layer and have high Global Warming Potentials (GWPs), contributing significantly to climate change.
As evidenced by dynamic legislation, which is doubly underpinned by a growing social movement, understanding the environmental impact of different refrigerants and transitioning to greener options is crucial for the HVAC industry. Not only does it help in regulatory compliance, but it also supports global efforts to combat climate change, on top of improving the efficiency and sustainability of HVAC systems.
The Environmental Impact of High-GWP Refrigerants
High-GWP refrigerants contribute significantly to global warming. For example, R-410A has a GWP of 2,088, meaning it traps over 2,000 times more heat than CO2.
This high environmental cost underscores the urgency of transitioning to low-GWP alternatives. HVAC professionals need to be at the forefront of this shift to mitigate climate change effectively.
Switching to low-GWP refrigerants can reduce your carbon footprint substantially. This not only benefits the planet but also aligns with increasingly stringent environmental regulations.
Emerging Low-GWP Alternatives
The HVAC industry is making strides in developing low-GWP refrigerants. These new refrigerants aim to offer the same performance without the significant environmental impact.
Refrigerants like R-143A and R-23 have high GWPs. Alternatives such as R-32, R-41, and natural refrigerants like ammonia have much lower GWPs, making them more sustainable options. You should also consider A2L refrigerants, which are approved by the EPA’s Significant New Alternatives Policy (SNAP) program. Under this program, the EPA evaluates factors like flammability, toxicity, safety, and more before approving the refrigerant for public use.
Hydrofluoroolefins (HFOs) are another promising category. HFOs like R-1234yf and HFO-1234ze have GWPs close to zero, making them an ideal replacement for HFCs in many applications. Natural refrigerants like CO2 and ammonia (NH3) are also another option. They have low or even negative GWPs and offer excellent performance, though they may require more specialized handling.
Challenges in Adopting Low-GWP Refrigerants
Switching to low-GWP refrigerants isn’t without its challenges. These can include higher initial costs and the need for specialized training. However, the long-term benefits often outweigh these challenges. Lower operational costs and compliance with regulations can lead to substantial savings over time.
With increasingly stringent legislation being enacted (see Local Law 97’s schedule, which sees a 40% decrease in emissions come 2030), we recommend making the switch to lower-GWP refrigerants as soon as possible. Inasmuch as upfront costs are pricey, the costs will only increase with penalty fees shall your building/facility remain non-compliant with the legislation.
Making the Switch to Low-GWP Refrigerants with Donnelly
Understanding and reducing GWPs is critical not only for the HVAC industry, but also for your commercial facility/business. By adopting low-GWP refrigerants and staying compliant with regulations, you can make a significant environmental impact.
For over 30 years, Donnelly Mechanical has served as New York City’s leading HVAC service provider. Always remaining ahead of the curve, Donnelly maintains a steadfast commitment to HVAC industry trends and serving clients appropriately. If you’re looking to lower energy costs and comply further with Local Law 97, the AIM Act, and more, please visit our website and get in touch with us today at 718-865-2294 to get started.
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