Purdue Conferences 2016, a simultaneous series covering research in the HVAC&R sector, is taking place at West Lafayette in the U.S. state of Indiana from July 11-14.
Reilly Professor of Mechanical Engineering Eckhard Groll, the general conference chair, said: “This year’s conferences are happening at a time when key international decisions are helping to define the direction of issues related to the environment, climate change, solar and other technologies.”
The U.S. Environmental Protection Agency’s (EPA) Significant New Alternatives Policy (SNAP) programme and the European Union’s F-Gas Regulation, which seek to phase down f-gas emissions, are also forcing the HVAC&R industry to improve the energy efficiency of their products.
“The question is; where is all of the energy coming from to operate these additional systems?” Groll said. “This expansion in air conditioning and refrigeration will drive greater needs for energy efficiency and environmental considerations.”
This year’s Purdue conference series includes the 23rd International Compressor Engineering Conference, the 16th International Refrigeration and Air Conditioning Conference, and the 4th International High Performance Buildings Conference.
Legislation: A driver of change
Many sessions are technical, giving participants an insight into the innovation that researchers are achieving and how their cutting-edge technological developments might be harnessed in the future.
Key speakers like Drusilla Hufford – director, Stratospheric Protection Division, Office of Atmospheric Programs, U.S. EPA – and Viraj Vithoontien, Program Leader at the World Bank Montreal Protocol Program, were on hand to provide policy advice to complement the technological innovations showcased by the world’s leading researchers.
R744 performing in warm ambient temperatures
Transcritical CO2 (R744) technology has long been hailed as a cutting-edge refrigeration technology. Participants heard how it had been successfully applied in warm ambient conditions in Italy, where hypermarkets have embraced it as a means of meeting the demands of the EU F-Gas Regulation.
Commercial refrigeration was not the only CO2 transcritical application on show at Purdue, however, with industrial applications becoming more varied.
Purdue attendees were treated to a presentation by Simarpreet Singh and M.S. Dasgupta, two engineers from the Birla Institute of Technology and Science in India, who showed how a transcritical CO2 heat pump system for waste heat utilisation in warm weather conditions had been successfully applied to a milk refrigeration plant.
The groundwater heat pump utilises the waste energy from an ammonia refrigeration system to generate heat to sterilise the milk at the same time, using the principle of cogeneration to deliver effective heat and cooling with natural refrigerants.
CO2 can be combined with other natural refrigerants, such as ammonia or water.
Steven Lobregeti, Jan Broeze and Carlos Infante Ferreire, from a joint project led by three Dutch universities, have found that 30% efficient savings can be achieved by flash freezing via a water-CO2 refrigeration system. They are testing their system in a fruit and vegetable plant and so far the results have been positive.
‘Improbable and impractical’ to adopt R32 in place of ammonia
Dr. Andy Pearson, from UK-based Star Refrigeration, was previously awarded a fellowship to ASHRAE for his work with natural refrigerants and eco-friendly refrigeration.
Looking at the new gases like R32, an f-gas that some hope will enter the industrial refrigeration market, Pearson’s research concluded that it would not just be improbable for R32 to replace ammonia in this application range but also impractical.
He cited the EU’s F-Gas Regulation as a major barrier to swapping the natural refrigerant ammonia for the HFC R32 in his research paper ‘R32 as an Alternative to Ammonia in Industrial Refrigeration’.
He also found other compelling reasons why end users would not make this change. R32 is expensive and the equipment that is being developed to use it has so far proved inefficient, he argued.
Ammonia, in contrast, has been used for such a long time in industrial refrigeration that “[it] has a good track record of safety, efficiency, ease of maintenance and reliability”.
Industry leaders such as Parker, Tecumseh, Emerson, Danfoss and Carrier also showcased cutting-edge natural refrigerant technologies at the event.