Heat exchangers made with copper tubes are ‘highly compatible’ with most low-GWP refrigerants for RACHP systems, according to the International Copper Association (ICA).
Nigel Cotton, Microgroove team leader for the International Copper Association (ICA), said: “In both laboratory and manufacturing environments, smaller-diameter copper tubes are proving to be a good match for eco-friendly refrigerants.”
The ICA identified refrigerants such as R-32 (GWP 675) and low-GWP HFOs such as HFO-1234yf and HFO-1234-ze, which have GWPs of 4 and 6, respectively, adding “Many more refrigerants that are blends of HFCs are HFOs are also under consideration for various applications.”
Mr Cotton said: “Traditional copper tubes with plate-fins are well suited for these new blends of eco-friendly refrigerants. The use of smaller-diameter tubes further reduces the effective GWP in applications since less refrigerant charge delivers the same capacity.”
The ICA added that copper also excels when used in heat exchangers for natural refrigerants, including hydrocarbons and CO2, pointing to the laws of mechanics, which state the “hoop stress” exerted on a tube decreases with diameter (when pressure and wall thickness are held constant).
It’s claimed that higher pressures can therefore be applied without increasing the wall thickness or lower wall thicknesses can be used.
Mr Cotton said: “When manufacturers use smaller-diameter copper tube, they can save on materials and increase performance in more ways than one.”