• Supermarket refrigeration: R744.com, on behalf of the Green Cooling Council from Australia (former NRTB), presented Australia’s first transcritical R744 system, running since 2007. The Angle Vale system, installed in a supermarket near Adelaide, is performing satisfactorily even at tough summer conditions, and has attracted the interest of several retailers for similar installations. Although monitoring of energy consumption is still underway, first estimates from the installers point to a better performance of the R744 compared to a conventional HFC-based one.

• Vending Machines: Daiki Shiomi from Sanyo presented the company’s latest updates concerning light commercial applications. The company has now completed development of a unique two stage rotary compressor, which reduces the discharge gas temperature and compressor load, hence leading to a big improvement in cooling effect and system efficiency. Sanyo’s field testing in summer conditions in Australia showed an increase of 17% efficiency of its CO₂ vending machines compared to equivalent units using HFC-134a. Having delivered already 30,000 CO₂ units to the Japanese market, Sanyo foresees a steep sales increase of its CO₂ vending machines and its whole range of CO₂ products, from heat pumps to display cabinets. On the cost side, Sanyo expects the price of components to go down as the amount of components manufacturing grow, reaching a point where the costs would be similar than the ones for conventional systems today.

• CO₂ Heat Pumps: Daikin gave an overview of the EcoCute water heaters market in Japan, the largest commercial application of R744 up to date with over 1 million accumulated sales. Daikin referred to ongoing developments on a swing compressor, and a key improvement: a new compact expander- compressor, whereby an expander would transmit recovered energy directly to the compressor to reduce compressor power input. This new mechanism can further increase the systems’ performance and efficiency, together with the optimization of heat exchangers.

A common message underlying all R744-related presentations was the possibility that the technology offers for developing countries to leapfrog from HCFCs to a long-term sustainable solution, as they can build on the industry experience with R744. This would avoid both ozone depletion and global warming impacts altogether. The reduction of initial investment costs and the technology transfer to develop installation and service capabilities remain as the main challenges to overcome in the coming years.

Large number of options

Next to R744 solutions, a wide array of possibilities was examined, with other natural refrigerants also taking a prominent role:
 

• Hydrocarbons: Heinz Jürgensen, from Danfoss, presented solutions for small commercial systems with Hydrocarbons. Danfoss insisted on the safety of the installations , especially given the small volumes needed for the systems. Additionally, Danfoss’ experience so far shows no efficiency penalty from Hydrocarbons compared to equivalent R-22 systems, and better efficiency compared to other HFC-based systems. On the other hand, the Australian specialist Energy Resources Group explained its experience in retrofitting large refrigeration systems and chillers with Hydrocarbons. The systems are helping reduce energy consumption by 17% while operating safely, following specifications at the time of installation. 

• Ammonia: Johnson Controls presented Ammonia screw chillers, which are already a common solution in Europe. With the advantage of high efficiency, the chillers using this natural refrigerant are quickly dropping in price as the capacity increases. Safety concerns are addressed via additional devices, such as sensors.