Flexible Refrigeration systems for the food industry with natural fluids, with particular reference to CO2

UE Directives tend to equate the benefits associated with the use of natural refrigerants and low environmental impact with those relating to the employment of traditional fluids. The actual Acts provide for obligations and penalties that may weigh on business and management, as well as influence the technical decisions at plant level. In this perspective, the aim of this paper was to realize a CO2 refrigeration system characterized by low environmental impact. The employment of this refrigerant fluid is partly consolidated and its use is increasing throughout Europe but it has not been adequately tested on agricultural products and foodstuffs. However, the possibility to realize a variable geometrical system is deepened, in order to meet a wide range of environmental and process conditions. A flexible prototype plant was designed and realized which is able to perform both subcritical and transcritical cycles, only varying the geometry of the circuit, according to both environmental conditions and product conservation needs. Having such a versatile refrigerating machine which could function as a laboratory test, it is possible firstly to determine, for a very specific application, the most suitable values of the parameters characterizing the process. In particular, to verify the feasibility of a possible solution only in foodstuffs applications where more stages of processing of the product at different values of temperature and humidity which currently require a device for each stage are requested, for example in the production of sausages

Impiantistica frigorifera innovativa con fluidi frigorigeni naturali

Nella seguente nota vengono esposte le linee programmatiche del progetto nazionale di ricerca sulle “Tecnologie innovative sulla frigoconservazione con fluidi refrigeranti naturali”e l’attività finora svolta dalle unità operative afferenti al progetto. Pertanto, dopo una sintetica introduzione sugli effetti prodotti dall’emissione di fluidi refrigeranti sull’ambiente, sono stati riepilogati i regolamenti emessi dagli accordi internazionali stipulati fra i vari Stati ed i limiti imposti dalla legislazione europea sull’uso dei gas fluorurati. Il progetto di ricerca ha previsto la costruzione ed il monitoraggio di tre impianti frigoriferi pilota che utilizzano i due gas naturali di maggiore interesse e cioè l’anidride carbonica e l’aria. Sono stati, quindi, esposti i criteri generali di progettazione degli impianti e la loro definizione costruttiva, nonché le metodiche con cui si ritiene di valutarne l’efficienz