Alternative Cooling Technologies conference, London, 1st February 2005
This conference, which was co-sponsored by the UK Institute of Refrigeration and organised commercially by RAC magazine, was well attended with about 140 people present. It was arranged in five sessions. In the first session, speakers from UK government departments gave an overview of the proposed EU regulation on F-gases (designed to ensure that emissions do not rise unchecked) and the associated mobile air conditioning directive (which phases out HFC use in this application from 2011). This was followed by an end user view from Alan Gerrard of Unilever, the global market leader in ice cream, who own of 1.8 million refrigerated cabinets worldwide. For this application Unilever see hydrocarbon refrigerants as the preferred option wherever this is commercially viable and legal. The speaker emphasised the company's corporate social responsibility and the perceived advantages of working with Greenpeace. It was acknowledged that a complete change of equipment would take some time. The second session was probably the most interesting to many of the delegates. Five speakers outlined the current state of commercial exploitation and development of carbon dioxide systems. Andy Pearson of Star Refrigeration presented the history and the characteristics of these systems, and predicted that they will become cheap, common, reliable and efficient. Jürgen S üss of Danfoss described the development of a reciprocating compressor range for CO2 at present in use in pilot applications. There is an expected production level of 60,000 units per year from mid 2006 and then increasing. A thermostatic high pressure control valve has also been developed. David Blankley of Grasso Products described development work which has made available a 1.5MW low temperature industrial refrigeration package. Open CO2 compressors in the 100-200m 3/h range will be available within a few months. Prof Giovanni Lozza from Milan discussed heat exchangers for CO2 and showed that conventional designs of fin and tube exchangers (but with thicker tube walls) will be suitable for most applications. There are advantages of using the higher temperatures in the gas cooler to reduce fan power by up to two-thirds, for a CO2 system compared to R-404A. In higher ambient temperatures a water spray can be used to enhance performance. Adrian Page of Nestlé showed several current applications of CO2 and described some feasibility studies showing good results. He was aware of 136 CO2/NH 3 cascade systems in use in Europe , mostly in food freezing and cold storage. Much more equipment is now available for many applications, including domestic heat pumps in the Japanese market. The next session concerned ammonia. This is a well-established refrigerant in widespread use. Anders Lindborg outlined technical and safety aspects. Then Lennart Rolfsman of York Refrigeration and Ian Mundie of Klima-Therm described available equipment in sizes from 100kW cooling upwards, and argued that the very long life of this equipment and its high efficiency make it the most economic option in the long term. The fourth session covered the application of hydrocarbon refrigerants. Daniel Colbourne of BOC Refrigerants looked at viable applications within the range of the revised EN378 standard to be published soon. He concluded that all applications are viable except multi-evaporator air conditioning and commercial transport air conditioning. He detailed a lifetime assessment model for a small commercial refrigeration cabinet, which showed that both emissions per unit cost and emissions per unit energy use favoured hydrocarbons. An enthusiastic presentation by Nick Cox of Earthcare Products provided data about hydrocarbons and details of equipment that is available. He expressed the opinions that heat pumps now offer the cheapest form of heating for houses, and that hydrocarbons are the irrefutable choice for car air conditioning. Some of his data looked optimistic, such as a future ground source heat pump for domestic use with a COP of 5.1. In the final session, Andrew Gigiel described the advantages of air and water as refrigerants, especially in open cycles. Water is well suited to small temperature differentials; air is well suited to applications with simultaneous heating and cooling and high temperature differences. There are current applications, but the need for a mass market to reduce capital costs is an unresolved problem. David Berchowitz of Global Cooling described Stirling Cycle equipment, which is now in use in some consumer and commercial applications and has the potential for wider use. This equipment offers the only practical solution for many specialised applications. To sum up, Dr Forbes Pearson of Star Refrigeration considered the future: change is inevitably coming, but HFCs will be around for some time yet. He foresees the use of isobutane for all sealed systems if US regulations could be overcome, CO2 cascade systems for distributed low and medium temperature systems, ammonia for medium and high temperature systems where human occupancy is low, CO2 volatile secondary systems for other high temperature applications, and transcritical CO2 soon when efficiency has been improved. It was interesting to compare this very commercially oriented conference with the IIR's Gustav Lorentzen conferences on the same subject. This RAC conference had no academic papers, no published papers, invited speakers only, and was relatively expensive. The objectives and audiences appear sufficiently different for the events to be complimentary rather than competitive. But no less than six of the authors at this conference also provided papers to GL2004, and a number of attendees were at both. RAC plans a conference on preventing refrigerant leakage on June 7th 2005.