Performances du R32 et du R290 en tant que frigorigènes alternatifs au R22 et au R410A en conditionnement d'air domestique

Selon les auteurs de l'étude, le R290 pourrait être considéré comme le frigorigène alternatif le plus adapté pour les conditionneurs d'air avec des échangeurs à tubes ailetés de faible diamètre. (en anglais)
In order to identify alternative refrigerants exhibiting favorable cycle performance in domestic air conditioning, S. Cheng et al.* assessed the performance of R32 and R290 as substitutes to R22 and R410A in a small split household air conditioner.

The experiments were conducted with a small (5-mm diameter) finned tube heat exchanger – allowing a decrease in the quantity and cost of copper used – based on the enthalpy method. The results showed that in nominal cooling conditions, the COP (coefficient of performance) of R32 and R290 were 26.8% and 20.4% higher than R22, 7.3% and 2.1% higher than R410A. And in nominal heating conditions, the COP of R32 and R290 were both 11.0% higher than R22, 5.3% higher than R410A.

The systems with R290 and R32 had similar capacities to that with R22 and R410A in heating mode, but a huge difference of capacities in cooling mode:  the capacity with R290 was similar to that with R22 and R410A but  the capacity with R32 was 20.7% and 4.2% higher.

According to the authors, regardless of the capacity difference, R290 could be considered as the most appropriate substitute in air conditioners with small finned tube heat exchangers due to its lowest optimal charge quantity (335g) which is even less than the half amount of the other three, as low refrigerant charge represents reduction in the volume of the compressor, evaporator and condenser.

Aiming at further lowering the charge of flammable R290, a suction line heat exchanger was used; the cycle performance was enhanced: +5.3% in capacity and +5.1% in COP; safety was also improved with a 6% reduction of the optimal charge (315g).

Cycle performance of alternative refrigerants for domestic air-conditioning system based on a small finned tube heat exchanger, Song Chen et al., Applied Thermal Engineering 64 (2014) 83-92