Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 52 S ection 02 TraTra dition a lly the market for larger chillers (from around 500 - 1000 kW) was dominated by R-11. R-11, which is a CFC, operates at lower pressures than other used refrigerants in centrifugal compressors. With the phase out of CFCs, some manufacturers replaced R-11 with R-123, which is an HCFC. There are currently no suggested replacements for R-123 so these systems will most likely have to be kept operating with R-123 until they are decommissioned at their end of life. Due to technical designs less suitable for this refrigerant, as well as concerns about toxicity and a reluctance to introduce a transitional HCFC product, most manufacturers have converted their production to R-134a chillers. For these larger systems, screws and centrifugal compressors are typically used. Due to the low efficiency of many old chillers and the lack of options for direct replacements retrofits in these type of chillers, they are more often replaced by new chillers: a state-of-the-art chiller system will often use 30% less energy than an old chiller installation, which often result in a short payback time on the additional investment to replace rather than retrofit an old unit (Gartland, Lisa, Positive Energy). 2.2 Chillers with HFCs Su mmary Chillers with HFCs R -22 is one of the most common alternative refrigerants in small and medium-sized chillers. For more than 10 years, a wide range of non-HCFC chillers has been available on the market. This includes chillers using HFCs, hydrocarbons and ammonia. These new chillers are often developed to have higher efficiencies than older chiller designs. Chillers are used mainly in centralised air conditioning systems and process cooling. For most chillers (except for those with R-123) there are several options: either to retrofit to the HFCs used in new systems or make a conversion to service blends. Before a decision to invest in a retrofit is taken, the status and performance of the existing plant should be evaluated. State-of-the-art designs often have 20-40% lower energy consumption than 10 year old designs. In the new system, the additional cost for non-HCFC technology is limited and significantly lower than that of a future retrofit. A continued installation of R-22 equipment will increase the country’s challenge to achieve the HCFC freeze in 2013. Ch illers are often (but not always) factory-built units that are intended to cool a liquid that can be water, or if at a lower temperature than approximately 5°C, a glycol or brine fluid. They can be air-cooled (i.e. the condenser is directly cooled by air) or water-cooled (i.e. the condenser is cooled by circulating water) with freeze protection if the climate is such that the water would risk freezing in winter. Their main application is for air conditioning in larger buildings, e.g. hotels, offices and public buildings such as hospitals and military complexes, and for process cooling in industries. 2.2.1 LarLarge low pressure chillers 2.2.2 Medium-sized and small chillers I n the segment of lower capacity chillers that traditionally used R-22 or R-12, non-ODS chillers have been available for the last 15 years, at the same time as R-22 chillers were still being introduced in some markets. The main alternatives are R-134a, R-407C and to some extent R-410A. R-134a is most common in equipment of larger cooling capacity and is Fig. 2.6 An older model of an air-cooled chiller assembled from “condensing units” used for wine production in Georgia. Fig. 2.7 Older standard air-cooled chiller manufactured in Europe with R-22, installed in Montenegro.