What is R723?

By shecco, published Feb 19, 2019 - 2 pages

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.

In terms of safety, the blend has to be treated like ammonia, according to Kälte und Klima Aktuell (read here ammonia safety parts one and two).

Read here about one of the latest R723 installations in Slovakia: 

Slovak dairy company opts for ammonia/ether system

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