It is a mixture of 60% ammonia and 40% dimethyl ether best suited for medium- to small-range applications.
Ammonia dimethyl ether (R723) is a non-fluorinated refrigerant blend that consists of 60% ammonia (R717) and 40% dimethyl ether (RE170). It has zero ozone depleting potential and a global warming potential (GWP) of eight. Eurammon considers R723 to be a natural refrigerant.
“Natural refrigerants such as ammonia dimethyl ether help to protect the environment and improve sustainability.” – Eurammon
The blend has 150% of the volumetric capacity of ammonia, making it more efficient in small to medium range applications up to 100 kW, with a higher coefficient of performance (COP). The compression end temperature is 15°C lower than that of ammonia, enabling the use of air-cooled condensers.
The blend is azeotropic, meaning that it does not change in concentration during evaporation or condensation. R723 works as a drop-in ammonia replacement in semihermetic compressors, so it can be used in retrofitting existing ammonia systems – with the help of an experienced refrigeration engineer.
“The energy efficiency of the azeotropic mixture is complemented by a high-performance coefficient and a high level of oil solubility.” - Eurammon
Apostol et al. compared R723 to R717 in a theoretical thermodynamic analysis. The researchers see advantages in both refrigerants. The blend has an approximately 30% lower latent heat of vaporisation and a higher evaporator volume heat load. However, ammonia is operated with less pressure. Pure NH3 also has a higher evaporator mass heat load without lowering the COP, which the academics name the most important advantage of R717.
“Consequently, the theoretical results highlight important advantages of replacing R717 with a R717 and DME blend, which fully justifies the new proposed family of refrigerants.”– Apostol et al.
Read here about one of the latest R723 installations in Slovakia:
Slovak dairy company opts for ammonia/ether system
By shecco , published Nov 12, 2018 - 2 pages