The carbon dioxide matter is certainly one of the most important in the opinion of plant manufacturers and maintenance operators today. Transcritical CO2 is a technical problem often “solved” by serial setups, where the “plug-in” version seems the panacea for all ills. However, the issue is much more complex and, not with the intention of complicating it but with the will of addressing towards an appropriate use, we try – with the support by Valentino Verzotto, historical member of the Technical Scientific Committee of Assofrigoristi – clarifying some method items.
A plant is made up by a series of elements and it is not conceivable to solve an – to say the least -enormous matter like efficiency by intervening on a single variable. The equation certainly has several unknowns but in recent times a message has been communicated to the market, a maybe “trivializing” or anyway simplifying message: the use of carbon dioxide as refrigerating fluid generates efficiency.
It is not our task, and neither our intention, to deny this message, which has true aspects and introduces an element of certain interest for a future when it will be possible to consider CO2 one of the possible tools to face the problem of emissions and of the impact on the ozone hole more smartly. However, we aim– precisely with the aid of whom has taken care of CO2 for a long time, such as Valentino Verzotto, a pioneer in the use of this fluid – at putting order in starting concepts, just to convey the concept that the discussion does not concern the efficiency of a refrigerant, anyway (in the case of CO2) questioned by its nature and by a critical point involving an extremely delicate management, the famous 32 °C.
The discussion about the use of carbon dioxide is important if faced by taking into account the whole of the issues it generates, from the choice of the compressor to the condenser and evaporator, with specific focus on their sizing, on the efficiency ratio created by the choice of properly mutually correlated elements, the need of assessing accurately all the problems generated by the pressure of this refrigerant, to succeed – without supposing of having accomplished the overview of technical matters with this very short list – in defining if the external environmental context determines the possibility of using the carbon dioxide plant as single system or it is opportune to opt for cascade solutions where the carbon dioxide circuit is subordinated to another with another refrigerant.
A real network of options that certainly give birth to potential efficiency but require an accurate study, as if we were dealing with a labyrinth where, at all crossroads, we must ask a question and reply coherently and sincerely, rethinking choices taken for granted and questioning them not for the sake of complicating our lives but instead in search of the best combination of elements and choices to achieve a real maximum possible efficiency.
An ambitious goal? Yes, certainly, but it is also true that, if this spirit of study, research, innovation and experimentation is missing, the so called standard or packaged solutions will be never able to implement fully those efficiency targets that the design and manufacturing suitability can deploy.
Therefore, a target that the Technical Scientific Committee of Assofrigoristi tries proposing through this thorough analysis, to invite players to achieve the best from a technology that may seem “serial”, but it is actually an open field for constant improvement, also through the innovative contribution by element manufacturers.