EXERGY ANALYSIS AND REFRIGERANT EFFECT ON THE OPERATION AND PERFORMANCE LIMITS OF A ONE STAGE VAPOR COMPRESSION REFRIGERATION SYSTEM
Autor/autori: Camelia STANCIU, Adina GHEORGHIAN, Dorin STANCIU, Alexandru DOBROVICESCU
Rezumat: Lucrarea prezinta o analiza comparativa a efectului agentului frigorific utilizat asupra functionarii si performantelor unei instalatii frigorifice cu comprimare mecanica de vapori intr-o treapta. Parametrii si factorii ce influenteaza performantele (din punct de vedere al puterii frigorifice, coeficientului de performanta, consumului de energie, etc) sunt estimate pe baza analizei exergetice. Diverse studii de sensibilitate sunt prezentate comparativ pentru cativa agenti frigorifici (R22, R134a, R717, R507a, R404a). Sunt prezentate rezultate grafice si numerice. Influenta raportului de comprimare este evidentiata pentru functionarea sistemului cu acesti agenti frigorifici, afectand regimul de functionare (temperatura maxima acceptata), respectiv performantele sistemului. De asemenea, se studiaza efectul subracirii si supraincalzirii. In concluzie, se prezinta o analiza comparativa a coeficientului de performanta definit pe baza energetica si a randamentului exergetic.
Cuvinte cheie: comprimare mecanica, instalatie frigorifica, analiza exergetica, subracire si supraincalzire, efectul agentului frigorific.
Abstract: This paper deals with a comparative analysis of the refrigerant impact on the operation and performances of a one stage vapor compression refrigeration system. Parameters and factors affecting the performances (in terms of refrigeration power, coefficient of performance, mechanical work consumption, etc) are evaluated on the basis of an exergy analysis. Different sensitivity studies are presented in a comparative manner for some refrigerants (R22, R134a, R717, R507a, R404a). Graphical and numerical results are included. The effect of compression ratio is emphasized for the system operation working with these refrigerants, affecting the operation regime (maximum accepted temperature), respectively the performances of the system. Also the effects of subcooling and superheating are shown. As conclusion, a comparative analysis between energetic base COP and exergetic efficiency is presented.
Keywords: vapor compression, refrigeration system, exergy analysis, subcooling and superheating, refrigerant impact.