WEST LAFAYETTE, Ind. — If hydrofluorocarbons (HFCs) are to have long-term viability, the low-global warming potential (GWP) versions will have to separate themselves from high-GWP types. And the survivors will have to play their part in energy efficiencies, especially in commercial buildings.
Those were some of the themes that emerged from the most recent concurrent conferences on compressor engineering, refrigeration/air conditioning, and high-performance buildings held at Purdue University. The biennial event drew 700 attendees this year, representing 30 countries.
More than 400 papers were presented and four plenary sessions were held over the four-day event. Dozens of research papers focused on the future use of low-GWP HFCs as well as hydrofluoroolefins (HFOs) and naturals like CO2, hydrocarbons (HCs), and ammonia. But virtually no attention was given to the long-term use of high-GWP refrigerants like R-410A, -404A, and -507, the most commonly used HFCs today.
In effect, the tone of the conference seemed to be addressing the current global, political, and regulatory arenas where significant contributors to global warming are seen as negatively affecting climate change. The focus remained on low-GWP HFCs and HFOs, which the industry is developing.
In addition to dozens of papers on the topic, low-GWP refrigerants were also afforded their own plenary session, presented by Mark McLinden from the Applied Chemicals and Materials Division of the National Institute of Standards and Technology (NIST). During the presentation, “Optimizing the Selection of Low-GWP Refrigerants: Limits, Possibilities, and Tradeoffs,” McLinden noted ongoing research involving low-GWP HFCs, HFOs, and natural gases will dictate what might enter the marketplace. “That’s all there is … really,” he said. “We have bumped up against the physical limits of the chemistry.”
He referenced four generations of refrigerants as defined by industry consultant James Calm. The “whatever-works” generation consisted of SO2, NH3, and first uses of CO2 and HCs. The second generation focused on chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) in response to safety issues of some of the previous-generation refrigerants. The third generation — HFCs — was in response to the ozone-depletion issue with CFCs and HCFCs. The fourth generation, low-GWP HFCs, HFOs, and natural refrigerants, serves as a response to global warming issues.
“Will there be a fifth generation?” he asked. “No.”
Two of the plenary sessions dealt with future trends in construction and operations on the HVACR aspect of what are being called high-performance buildings.
Achilles Karagiozis, director of building science for Owens Corning, noted that commercial buildings today account for 40 percent of energy consumption, with 75 percent of the power needed to operate the buildings coming from fossil fuels.
Yet, designing strictly for energy efficiency does not necessarily equate to a high-performance building,” he said. He cited, for example, a mechanical cooling system that may be efficient, but very noisy. And even as designers and builders move toward what is called net-zero-energy buildings, he pointed out that “the customer does not (really) want energy efficiency. He wants comfort and durability.” He then took attendees through the complex aspects factoring into wall design and construction.
Roland Risser, director for the Building Technologies Office of the U.S. Department of Energy (DOE), reviewed DOE projects related to “driving innovation, accelerating to scale, and locking in savings.” Among the HVACR projects he referenced were integrated geothermal heat pumps with variable-speed fans and compressors using waste heat, a heat exchanger with a vapor chamber and heat sink, and an electrochemical non-vapor compressor using water as a refrigerant rather than an HFC.
Another plenary speaker was Jack Sauls, retired from Trane, an Ingerosll Rand brand, who talked about the history and future of screw compressors. He stressed the need to draw off research of the past in developing the next generation of such equipment.
Also addressing the gathering was Tom Phoenix, ASHRAE president, who spoke about ongoing ASHRAE standards, especially those related to energy performance and building ratings. With his talk coming at the start of the conference, he told attending HVACR professionals from throughout the world: “Our industry needs many more minds talking to each other. We will be judged by our performances, not our promises.”
Publication date: 8/25/2014