Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 58 S ection 02 Fig. 2.16 Chiller used for 20 years with R-22 that was retrofitted to R-422D. 2.5 Retrofit of R-22 chiller to R-422D (oil change not required) I n London a large R-22 chiller with an inverter was retrofitted to R-422D with good performance documentation before and after. The change of refrigerant was conducted on a machine originally installed in 1988 and the machine has run successfully 24 hours/7 days a week for 20 years. The machine comprises two Bock compressors, each driven by 37.5 kW motors with power inverters to allow variable speed. The approximate cooling capacity is 400 kW. This case describes the retrofit project, which has been executed in London by the Business Edge Technical Team in June 2008. The machine is water cooled and is served by large cooling towers on the roof of the building. This water chiller is unusual insofar as it is probably the only Variable Refrigeration Flow (VRF) water chiller to have been constructed in the UK at that time. Even now it is fairly unique as it is such a large machine and features variable speed reciprocating compressors rather than screw, scroll or centrifugal compressors. The control technology provides for full floating suction and floating head pressure control and delivers water at 8°C to a very precise steady state accuracy, this being a requirement of the project in order to prevent excess latent cooling within the machine/data rooms that it serves. These data rooms are critical to the large financial institution, which rely on this machine extensively to support their business. Following initial research, it was agreed that the most appropriate refrigerant would be Isceon™ MO29 (ASHRAE Reference Number R-422D). Given the critical nature of the application, it was decided that it would be wise to prepare all tools and equipment, consumables and recovery cylinders in such a way as to enable the machine to be retrofitted with R-422D and then run a performance evaluation test using ClimaCheck™ Performance Analyser. If this would identify that there was a problem with the R-422D, either in terms of its thermal performance, power input, COP and so on, or even worse, problems with oil return at low refrigerant velocity when the machine runs at prolonged low capacity and low speed, it would then be possible to recover the R-422D and reinstitute the R-22 immediately, in order to Su mmary A financial institution replaced its R-22 in chiller with a varariabable speed to “drop-in”/”service” blend developed to minimize cost of retrofitThis case describes the conversion of a 20 year old R-22 close control chiller that the end user decided not to replace (due to its good track record), but instead to extend its life by changing to a non-ODS service blend. After evaluating available alternatives, the decision was to replace the R-22 with R-422D - a service blend that can be used with the existing oil. The change was done according to the recommendation of the refrigerant supplier. The result was that R-422D worked well in this application and the method could be carried out in a cost effective way. The system has been running trouble free for one year after the change. Background data/information given for this installation comes from Mike Creamer, Business Edge Ltd (Business Edge Ltd) located in Waterlooville, UK. The description is based on the data received from the company, but as regards the selection of information and interpretation, the responsibility is with the author of this report.