ASHRAE Winter Conference: R744 seminar

For the first time in a long time, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) had organised a seminar specifically about the natural refrigerant R744. The event discussing CO2 systems, components, and applications sparked high interest (+ Photo Gallery).

On Tuesday, 27 January, more than 100 interested individuals crowded in the small room to accommodate the first CO₂-only seminar organised by the leading U.S. industry association ASHRAE in a long time. Attended by CO₂ experts, newcomers to the natural refrigerant, and chemical refrigerant manufacturers, the event discussed the use of CO₂ in vapor compression systems, explored R744 compressors for commercial and industrial refrigeration, and transcritical refrigeration cycles using hermetic compressors.

The event “CO₂ Systems, Components and Applications” was chaired by Georgi S. Kazachki, ASHRAE Fellow and representing Cryotherm. It was part of the extensive technical programme hosted by the ASHRAE Winter Conference “Engineering Tomorrow… Today”, held from 24-28 January in Chicago. 

The Presentations

Ecole de Mines: Denis Clodic started with a basic introduction about the properties of CO₂ and its safety classification as A1 - the safest possible category, as defined by ASHRAE. Outlining the way forward, he mentioned expanders and ejectors as means to increase efficiencies even further. Clodic went on talking about the US American market where cascade systems with ammonia would be recognisable as a trend.

Dorin: Giacomo Pisano confirmed that already 5,000 transcritical Dorin compressors are commissioned worldwide. Working together with Swedish manufacturer Green&Cool, Dorin has provided compressors for 120 units running in Europe. According to own estimations, about 250 supermarkets are already working with transcritical CO₂ systems in Europe alone. For more details, see the video interview taken at the AHR Expo.

Bitzer: Herman Renz summarised main conclusions for CO₂ compressors in commercial and industrial applications. Compared to R22, CO₂ has a six times higher cooling capacity in the low-temperature range, while in the medium temperature range, R744 would have a five times higher cooling capacity than R404a. Renz considered economizer solutions to still promise many opportunities for further efficiency improvements.

Sanyo: Masayuki Soma from the world leading brand Sanyo started with a general introduction about natural refrigerants that are sold around the world in fridges (hydrocarbons), industrial (ammonia), and commercial refrigeration systems. By 2010, one million CO₂ heat pumps are expected to be sold in Japan. Sanyo has developed new large models of 3000W for 9kW heat pumps used for Nordic areas. The “split cycle” developed by Sanyo can achieve high efficiency and cooling effects. Even at -20°C, the COP is increased by 17%. Taken over one year, the COP would increase by 8%.