ENERGY ANALYSIS OF REFRIGERATION SYSTEMS WITH CO2

Dandanes se klasični hladilni mediji, kot so freoni, umikajo iz uporabe oziroma so v hladilni tehniki že prepovedani, saj jih zamenjuje vse bolj priljubljen, ekonomsko in ekološko upravičen medij, ogljikov dioksid (CO2). Uporaba tega medija še ni tako razširjena zaradi specifičnosti izvedbe in prilagoditve hladilnih sistemov, zato se v večini primerov uporablja kot sekundarno hladilno sredstvo v kaskadnih sistemih. Da to dosežemo, moramo vse tlačno obremenjene elemente sistema prilagoditi posebnim zahtevam. V diplomskem delu sem se osredotočil na prednosti in slabosti CO2 sistemov, njihovo delovanje ter termične in fizikalne lastnosti CO2. Dejstvo je, da se danes o CO2 (v hladilstvu se uporablja oznaka R-744) veliko govori. Velika večina ljudi misli, da je R-744 škodljiv plin, a je v resnici zelo koristen in uporaben, če ga znamo pravilno izkoristiti. V nadaljevanju bo R-744 predstavljen kot zamenjava za obstoječe sisteme. Sam osebno menim, da se bo trend »zelene miselnosti« nadaljeval. Verjamem, da bo v prihodnjih nekaj letih uporaba freonov (F-plini) zakonsko omejena in kasneje tudi prepovedana.Nowadays, classical cooling media like freons get removed from use or they are already forbidden in cooling technique, because they are changed by more popular, economically and ecologically more justified medium – carbon dioxide (CO2). However, use of this medium is not very wide due to specificity of design and adjustment of cooling systems, and therefore is mainly used as a secondary cooling agent in cascade systems. For achieving this we have to adapt all system elements under pressure to special requirements. The diploma thesis is focused on advantages and disadvantages of CO2 systems, operation of CO2 systems and thermal and physical properties of CO2. It is a fact that CO2 (in cooling technique is used a mark R-744) raises many discussions. A big majority of people think, that R-744 is a harmful gas. However, it is very beneficial and useful, if it is properly used. The thesis continues with presentation of R-744 as a substitute for existing systems. My opinion is a trend of »thinking green« will go on. I believe that in a near future use of freons (F-gases) will be legally limited and later also forbidden