What is driving the need for refrigerant transition?

Towards the end of 2016, two agreements were made regarding refrigerant transition. The Montreal Protocol Amendment Agreement and the U.S. Environmental Protection Agency (EPA) Significant New Alternative Policy (SNAP) Ruling. The Montreal Protocol Amendment Agreement was signed by 197 countries on October 15, 2016 in Kigali, Rwanda. The objective of the amendment is for individual countries to take actions to address greenhouse gas emissions through the phase-down targets of HFC refrigerants in all industry sectors. The overall target goal is to achieve an 80-85 percent global reduction in CO2 equivalents by 2047. The agreement does not identify a phase out of HFC refrigerants, like the original Montreal Protocol agreement for ozone depleting refrigerants

Continued use of natural refrigerants – ammonia, CO2, and hydrocarbons, where allowed by codes and customers. Transitioning from HFCs to low GWP HFO blends, or pure HFOs where natural refrigerant solutions are not appropriate. Where GWPs below 300 or 150 are mandated the current leading HFO low temperature refrigerants include: R515B, R516A, R-1234yf or R-1234ze(E).

All natural refrigerants have zero Ozone Depletion Potential (ODP). Natural refrigerants have extremely low Global Warming Potential (GWP). In fact, ammonia has a GWP of zero while carbon dioxide has a GWP of one. Natural refrigerants are the cost-efficient solution. Systems utilizing natural refrigerants are very eco-friendly. In cases where none of the above refrigerants are allowed by codes, low GWP HFOs or HFO blends can be supplied in existing equipment.

As outlined in the Johnson Controls Refrigerant Stewardship Model, energy efficiency is the ultimate priority to reduce the carbon footprint of HVAC products. To illustrate this, let’s look at a commonly used piece of HVAC equipment that is used in many buildings throughout the world – a chiller.

A typical water-cooled centrifugal chiller will contribute 65,000 pounds of CO2 emissions associated with energy consumption per 100 tons of cooling capacity each year. This value may be twice as high for air-cooled chiller equipment and 30 to 50 percent higher without the use of energy-saving technology within chillers, including variable speed drives. Emissions associated with energy consumption are called indirect emissions.

Conversely, with typical equipment leakage rates, the annual carbon footprint associated with refrigerant leaks would be close to 5,000 pounds of refrigerant for every 100 tons of cooling when utilizing common HFCs. Emissions associated with refrigerant leaks are called direct emissions. For system designers and owners keen on solutions that reduce carbon footprint, understanding the climate impact of chilled water systems and designing or specifying higher efficiency products will have the greatest impact on reducing carbon footprint. When selecting new chiller or heat pump products, consideration must be given to the following key factors:

• The Energy Source: What is the carbon intensity or emission factor of the energy supplied to the plant?
• The Technology: What is the latest in energy-saving technology for the equipment type required? How efficiently does the equipment perform in all operating conditions (loads, temperatures) that the site will see?
• The Operating Sequence: How and when will equipment stage on and off? Are there efficiencies in pumping and piping strategies? If carbon intensity changes throughout the day, how can thermal energy storage be used to shift demand?

After efficient design, maintenance is the next most critical component of reducing CO2 emissions of HVAC equipment. These reductions are in both direct and indirect emissions. Indirect emissions being the largest component of chiller footprint, consider that simply increasing the interval between routine maintenance activities such as condenser cleaning may result in efficiency penalties of three to five percent, or over 3,000 additional pounds of CO2 annually. Direct emissions, too, can be mitigated with proper maintenance. Frequent checks on refrigerant level can alert the plant room operator to potential leaks, allowing early inspection and mitigation before significant refrigerant leakage occurs, maintaining a lower carbon footprint of the equipment. Well-maintained chiller equipment operates with annual refrigerant leakage rates of below one-half percent, while poorly maintained equipment may leak up to five percent of its charge annually.