Summary of two papers of the 9th International Conference on Compressors and Coolants (ICCC2017)
The IIR 9th International Conference on Compressors and Coolants (ICCC2017), which took place in Bratislava, Slovakia, in September 2017, addressed advances in compressors but also refrigerating technologies and alternative refrigerants, as illustrated by the two following paper summaries:
- Ejection systems can be driven by free or inexpensive low temperature heat source, either solar or waste heat, as the main source of energy instead of electricity. In their paper*, K. Smierciew et al stress that these systems can be thought as a real alternative to compression devices in air-conditioning technologies. Ejection refrigeration systems correspond to a modification of vapour compression cycle. Instead of pressurising the refrigerant with a mechanical compressor, an ejector compresses refrigerant vapour flowing from evaporator and discharges it to the condenser. The motive vapour is generated in the vapour generator, which is heated by low-temperature heat source.
Numerical and experimental investigations presented by the authors confirmed that the ejection cycle operating with isobutane can effectively be driven by low temperature heat source, e.g. lower than 75°C. Under this range of motive temperature heat sources, the ejection cycles can be considered as truly competitive in comparison with absorption refrigeration systems.
*SMIERCIEW K. et al, Development of numerical modelling of isobutane vapour ejector. In: 9th International Conference on Compressors and Coolants, September 6-8, 2017, Bratislava [online]. Paris: IIF-IIR, 2017, 8 p.
Available in Fridoc: http://bit.ly/2kTZkQt
- In their paper*, J. Sustek and P. Tomlein compare selected parameters of a cooling circuit following replacement of R404A with R448A and R449A (see properties in “Replacement of R404A in supermarkets” news on page 3) . Measurements were made at various refrigerant charges, from 300 g to 1000 g. At a charge of 400 g, optimal subcooling was achieved and superheating was nearly optimal. In comparison with R404A, TEWI values were 13.3% lower with R448A and 19.2% lower with R449A. The highest cooling capacity was obtained with R448A. Disadvantage of refrigerants R448A and R449A is higher discharge temperature. Measurements also proved the need for adjusting of thermostatic expansion valve after the retrofit.
*SUSTEK J., TOMLEIN P. Energetic efficiency of cooling circuit depending on the charge of the previous and new alternative refrigerant. In: 9th International Conference on Compressors and Coolants, September 6-8, 2017, Bratislava [online]. Paris: IIF-IIR, 2017, 8 p.
Available in Fridoc: http://bit.ly/2ihu0dI