In every great journey, there is a myth that must be slain. At the beginning, the conservative barons of refrigeration said that CO2 was not suitable for refrigeration tout court, years later faced with the evidence of the first successful plants, the criticism shifted decreeing that CO2 belonged only to the frozen North. They drew an imaginary line across themap, the “CO2 Equator”, proclaiming that beneath the fierce Mediterranean sun, this technology would wither and fail.

We set out to tear that border to pieces demonstrating that with the right technical architecture (optimized cycles and ejectors) the R744 is competitive even under the sun of the south.

The year 2013 was the turning point for the expansion in the southern Europe: armed with optimized cycles and our newfound ejectors, we marched south and we conquered France, Spain, and my homeland, Italy.

Shortly after, the wave of innovation reached Eastern Europe, with the first plants in Poland, Croatia, and Romania. Different manufacturing techniques were studied by the manufacturers. For example some used welded carbon steel for the piping, while others adopted stainless steel. It was an important element, much different from previous refrigeration installations with HFC, where brazed copper was used. Advansor (Dover) mainly was expanding the sales in its market, concentrating in standardization, while Enex was more specialized in R&D, thanks to the connections with Sintef and CNR of Padova.

A good help for spreding CO2 technology came from Shecco, with its informative activity. More suppliers introduced in their range components designed for CO2- compressors, valves and heat exchangers – so competition at all level started. A “new” alloy (K65) was introduced for the piping by Wieland, which for small plants allowed to use brazingprocess, instead of the more demanding welding.

In 2015, as the new European F-Gas regulations legislated clear limitations of synthetic fluids, the market finally understood: the era of chemistry was ending. Of course CO2, being no toxic and nonflammable, was the candidate for retail refrigeration and light industrial refrigeration.

One of the most extraordinary thermodynamic advantages of CO2 in the transcritical cycle is the gas temperature at the compressor discharge. While in traditional systems the discharge heat has a low temperature and it is difficult to reuse, with CO2 the refrigerant temperature after compression can exceed 90-100°C, making possible since 2008, todeveloped solutions to recover part of the heat available to produce domestic hot water or space heating, practically at zero cost.

The true masterpiece was painted in 2014, in the mountainous embrace of Trentino-Alto Adige. Working with our trusted local partners at Realtime, we built the “All-in-One.” The refrigeration rack ceased to be a mere cold-maker and it became the beating energy heart of the building.

Using the same system, we gave cold for food display and storage, and also produced winter heating and sanitary hot water at absolutely zero cost; moreover, while in summer, the unit was able to offer air conditioning to the store, creating a system capable of simultaneously producing refrigeration, space heating and cooling. A perfect example of the circular economy applied to engineering.

We continue our innovation journey and by 2016, we introduced a radically new chiller design based on the principle of the gravity-flooded evaporator that was new for CO2, but well known in industrial ammonia systems. Installations for skating rinks were done in Scandinavia by Green&Cool and Huurre, and by all the companies in general in light-industrial plants.

A new sector for CO2 chillers was the north-Italian wineries, introducing environmental advantages in this demanding sector. Shortly after, it was introduced a variant of gravity-fed chillers featuring the ejector (another Enex invention). This adjustment allowed for an efficiency improvement of approximately 10% specifically during peak thermal conditions, where CO2 refrigerant chillers typically struggle the most.