Alternatives to HCFCs in the Refrigeration and Air Conditioning Sector 68 S ection 02 C onstanta is a port town on the coast of the Black sea in Romania. The supermarket in the Tomis Mall had two central refrigeration plants operating on R-22: one for medium temperature (MT) and one for low temperature (LT). Both systems had four semi hermetic compressors. The supermarket owner wanted to select an alternative technology that would allow them to be in line with their environmental strategies and to avoid a future unplanned retrofits to replace R-22 in case of a failure or large leak. The decision was to retrofit to R-404A so that they would be using the same refrigerant as they use in new plants. Drop-in blends were not considered to be a viable option due to lack of experience and uncertainty of future availability and price. The retrofit was carried out through traditional oil changes. The retrofit was done during a renovation of the store while it was out of use. The first step was to evaluate the system and replace a number of gaskets and stop valves. The oil was replaced during the major upgrade of the plant. As the last step before restarting the plant, the oil was changed through drainage from oil reservoir, suction-, and liquid receiver through their drain plugs. The new polyol ester oil (Triton™ SEZ 32) was introduced in the oil reservoir by applying a vacuum. After two days of running the plants, the oil was changed once again. Approximately 50 litres of oil was required. The results of the pre-retrofit calculations and the follow up after retrofit are shown in the two tables below, one for the medium and for the low temperature system. Background data/information given for this installation comes from Adrian Balaoi. 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. 2.23 Typical supermarket display cases for a central system with “low temperature” cases in the front and “medium temperature” in the back. cold roomshop areadisplay cases Fig. 2.24 Supercritical CO2 system with gas cooler operating at pressures 2 to 3 times that of conventional systems.