Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 49 S ection 02 Th is retrofit was performed to demonstrate the feasibility of retrofitting a standard R-22 split system to R-407C (one of the HFCs blends used in manufacturing of new units) without doing repeated oil changes. The method implemented was “forced flushing” with a flushing unit developed to use the existing refrigerant to remove the old oil and contaminants from the system. This method has been used extensively on some markets (in particular Sweden, Norway, Germany and Spain) in the transition from CFC/HCFCs to HFCs as well as for flushing after compressor failures (so-called “burn outs”). The method minimizes the number of oil-changes required and makes it in many cases possible to perform a complete retrofit to the new oil and refrigerant in one visit. As the old oil often can contain contaminants from many years operation, it is an advantage to minimize the amount of the old oil mixed with the new. In most cases there is no need to use suction line filters if the system is efficiently flushed clean prior to the change of oil and refrigerant. In this particular case, the system retrofitted was a Hitecsa unit (model ACHB 1001 – 1011013) with a nominal cooling capacity of 29.6 kW. The nominal charge of refrigerant was 7.8 kg. To ensure that the system was in good shape before initiating the retrofit, it was analysed with a Performance Analyser system that can be connected in 20 minutes on site without pre-installed equipment (ClimaCheck™). To document the performance before the retrofit is important to ensure that the system is in good shape and has acceptable performance to ensure that a retrofit is really justified – see chapter 1.6.1 for more details. In case there are problems in the system, it is important and cost effective to correct these in connection with the retrofit. In case of serious problem or low efficiency it is better to invest in new equipment rather than spending money on an inefficient unit. The case described below shows the method for a change to R-407C, which is an alternative used for new systems (the most similar in capacity and pressure to R-22 in air conditioning applications). The advocates of this method argue that the advantage of flushing is that you start with a minimal level of old contaminants in the system in a cost effective way. If by doing this the old oil can be removed more cost-effectively than with repeated oil-changes, and if the system is also cleaned, there is no reason not to use the “standard” refrigerants and ester oil. These retrofits with flushing can be done in the field or by bringing the systems in for upgrading and do the retrofit in a workshop. A conversion with a drop-in/service blend is described later in this report in the case study describing the retrofit of a chiller. It should also be noted that in a new system, the additional cost for non-HCFC technology is minimal and significantly lower than any future conversion/retrofit. A continued installation of R-22 equipment - in spite of the availability of alternatives - will increase the challenge to achieve the freeze level in 2013, since regardless of retrofit method there is a cost and some risk of decreased performance. Background data/information given for this installation comes from the CSF, SA in Spain. 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. Fig. 2.2 Flushing unit designed to flush out the oil from the system with the “old” refrigerant.