Blends of HFOs and HFCs are being developed to optimize performance and safety. Whether using HFOs, natural refrigerants or blends, HVACR manufacturers must innovate technologies that maximize efficiency and minimize risk for the selected refrigerant.
Development of new technologies make it easier for manufacturers to balance safety and environmental responsibility. Some leading retailers have been using R-290 (propane) in equipment for over a decade. Taking advantage of R-290’s excellent thermodynamic properties—such as volumetric capacity, capacity and coefficient of performance (COP)—systems are operating successfully with a charge limited to 150 grams (5 ounces) for safety. Further research and product development led the International Electrotechnical Commission (IEC) to propose a 500-gram (1.1-pound) limit for R-290 in single commercial refrigeration appliances. The new IEC 60335-2-89 standard was passed in May 2019.
As time passes, it’s logical to think that Europe and the U.S. will continue to explore the balance between safety, efficiency and the environment—but not at the expense of endangering users and technicians.
New design and safety measures are needed to avoid flammability in occupied spaces and during servicing. For over a century in the U.S., HVACR manufacturers and service technicians have been working with A1 refrigerants.
The service industry, in particular, will need to become more familiar with flammable refrigerants. “Installation and service are the areas where proper guidelines, training, certification and standards are the most important,” explains Bill Goetzler of Navigant Consulting. “The lines carrying flammable refrigerants may be opened during various servicing operations, and service personnel also may be working with a high-temperature ignition source. Those are really places to be very careful and to be sure we've got standards and guidelines in place to minimize the risk.”
Safety is a vital factor relative in a refrigerant sustainability triangle that includes environmental and economic factors
Refrigerant Sustainability Triangle: Safety considerations involve the planet and people. Training and certification programs of service technicians are essential to reducing risks. Economic factors primarily include first costs for equipment and installation. Optimized system design and rebates/incentives/tax credits can speed up the return on investment (ROI). Environmental considerations involve a mix of refrigerant GWP, energy efficiency in real-world operation and integration with demand response, thermal storage and using power supplied by a decarbonized grid.
Other factors come into play depending on the properties of the refrigerant. With some HFO refrigerants, for example, flammability can present a safety issue, as previously discussed. Cost can also be a factor, as HFO formulations are more expensive to produce, and supplies are constrained. Finally, environmental concerns can still be an issue in several countries, because some HFOs break down in the lower atmosphere, forming fluorinated products. Trifluoroacetic acid (TFA) is an HFO breakdown substance but also occurs naturally in seawater. Hydrogen fluoride (HF) is another HFO breakdown substance which is very toxic. The small amounts of TFA and HF are not expected to pose global or regional problems.
Four technological developments that can build a steady transition platform
The search for refrigerants that perfectly balance environmental, economic and safety concerns is continuing. Unfortunately, this quest throws customers and end-users off balance. Planning is stressful when the future is subject to change. Fortunately, in recent years, technology has developed to the point that it is possible to build a long-lasting platform for low-GWP commercial refrigeration. Proven technologies are now available in four areas:
- Developments in CO2 refrigeration
- Developments in Demand Response
- Developments in thermal storage and related thermal-shifting technologies
- Developments in the decarbonized grid