Koura to present lower GWP R410A alternative
Refrigerant manufacturer Koura will present details of a new lower GWP A2L refrigerant blend for air conditioning applications at the forthcoming Chillventa exhibition in Nuremberg.
Koura’s new refrigerant R468C is described as a lower GWP fluid that can retain the performance benefits of R410A or R32.
Recently classified by ASHRAE as a non toxic, lower flammability A2L refrigerant, R468C blends 42% of R32 with 52% of R1234yf and 6% R1132a. This combination would give the refrigerant a GWP of around 286, a significant reduction on the 675 of R32.
However, the inclusion of a significant proportion of R1234yf suggests it will be more expensive than the refrigerants it is designed to replace.
The properties of R468C are said to be close to those of R410A, with a “slightly higher” critical temperature. Koura predicts temperature glides in evaporator and condenser to be in the region of 4-5K.
A simulation study was recently carried out by a team from the Center for Integrated Building Systems at Oklahoma State University, comparing the performance of R468C in a four-circuit fin and tube heat exchanger originally designed for R410A.
In a paper presented at the 19th International Refrigeration and Air Conditioning Conference at Purdue University in July, team member Matin Ghadiri presented the test results from 24 simulations covering three different saturated suction temperatures (5°, 10°, and 15°) in a dry evaporator testing mode.
It was found that R468C required a higher refrigerant flow rate (between 30-60%) for identical superheat ΔT and SST, resulting in a 30%-57% higher cooling capacity but a lower COP of about 10% compared to R410A.
The team says future work will include modifying a range of other parameters, including tube length and diameter, fin types and density, as well as a wider variety of coil sizes and refrigerants circuitries.