This was a premiere for France in an operation of such a highlighted extent with a conclusive result – being a problem solution combining feasibility and reliability.
It has been shown, that after 2010, R-22 will have considerable disadvantages for the servicing of equipment operating on this particular fluid refrigerant.
One of the first to react to this situation has been Casino, which, in seeking to address the future in good time within the scope of its ongoing policies of development, retained its servicing and consultancy engineers, Alpes Réfrigération for a conversion of its direct cooling system at Géant de Gap (5000 sq.mtrs. floorspace).
In order to effect a retrofit, Casino selected to use R-427A on the advice of Alpes Réfrigération. R-427A has been developed by Arkema under the commercial brand name of Forane® FX 100 and is distributed in France by Climalife. In fact, among the substitutional products currently available on the market, Forane® FX 100 is one of those products, which best combines the conservation of previous performance and enables similar energy consumption factors as those attributable to R-22.
Central direct cooling equipment
The conversion operation required no major modification of the system other than the mandatory replacement of the original oil by a polyolester oil. The equipment producing direct cooling for feeding the refrigeration lines of the climatised roomspace of the hypermarket and its 26 refrigerated product cabinets, comprises a Copeland plant air condensation plant with five D6DH3500 compressors of 40 horsepower each.
Rapidity of implementation
Two teams of four technicians from Alpes Réfrigération were required to carry out the conversion work in record time.
On Saturday 31st March at 20:00 h p.m., the hypermarket closed its doors to the public, the central refrigeration plant was shut down and the draining down of the R-22 was able to commence. Four extraction machines were installed for disposing of the R-22 fluid in an initial phase, and the gas during a second phase. During the operation, the third phase for extracting the oil was carried out and certain aspects of the plant were improved for ensuring future simplicity of servicing and maintenance.
To obtain the best returns of oil and thermal exchange at the heat exchangers, the circuit oil was replaced three times in two shifts whilst retaining the R-22 in the installation, and in a third phase whilst draining down the R-22 and recharging with R-427A. The draining of the equipment was effected by means of five extraction pumps connected to the refrigeration circuit and required six hours. The second team of technicians then proceeded to recharge the system with R-427A from ten flacons of 52 litres.
The conversion work was completed by 10:00 h a.m. the next day and the equipment re-commissioned. The 500 kgs of R-22 recovered were then passed to Climalife for retreatment. The team then conducted various adjustments to optimise the functioning of the installation and also carried out a precise inspection for detecting any leaks, to ensure an optimum functioning of the system. The measures were also taken as a comparison of the new performance of the equipment as against that produced with R-22.
The whole operation was an entire success in view of the prescribed deadline (to enable the hypermarket to open its doors again on the following Monday morning) as well as from the aspect of the performance obtained.
Comparative results of R-22 as against R-427A (FX 100) for a refrigerating cabinet
| Products | Units | R-22 | R-427A |
| Details Registered | 22 March 07 | 01 April 07 | |
| Central Total Charge | kg | 500 | 500 |
| Evaporation Temperature | °C | – 9 | – 9 |
| Evaporation Pressure | bar | 3,7 | 3,5 |
| Distillation to Evaporation Differential | K | 0 | 3,9 |
| Distillation to Condensation Differential | K | 0 | 4,8 |
| Condensation Temperature | °C | 34,2 | 33,5 |
| Condensation Pressure | bar | 13,3 | 13,4 |
| Temperature at Completion of Compression | °C | 83 | 70 |
| Mass Discharge | kg/s | 0,034 | 0,033 |
| Liquid Volume Discharge | dm3/h | 109 | 114 |
| Refrigeration Rating | kW | 5,34 | 4,73 |
| Compression Rating | kW | 1,42 | 1,35 |
| COP refrigeration | – | 3,8 | 3,5 |
R-427A combines the maintenance of optimum performance and displays a power consumption similar to that with the R-22 refrigerant.
Author : S. keller