Exergetic analysis of low gram nano-refrigerant charge for transport application

Limited gram charge is beneficial in transport refrigeration by sustenance of flammability limits for safety. Herein, an experimental investigation of 0.11 vol. % of titanium IV oxide doped with 30 g each of R600a and LPG as R6ooaAl2O3 and LPGAl2O3 nano-refrigerants were retrofitted into a 102g R134a vapour compression refrigerating system. At steady state, the performance of the system using unblended R134a, R600a, LPG refrigerants, R600aAl2O3 and LPGAl2O3 nano-refrigerants were examined as a function air evaporator temperature and compressor characteristics; discharge pressure, power consumption, compressor exergetic defect, coefficient of performance and exergetic efficiency. At 80g charge, R600a, LPG, R6ooaAl2O3 and LPGAl2O3 had higher COP; Exergetic efficiency; but lower Total exergetic defect of  2.9, 11.3, 9.7 and 14.1%; 19.4, 22.1, 31.8 and 29.4%; and 34.1, 43.6, 56.3 and 58.6% than R134a. R134a has higher discharge pressure of 0.25, 0.12, 0.77 and 0.84 Psia/ 0.77, 0.12, 0.84 and 0.25 Psia; higher power consumption of 14.79, 12.23, 27.83 and 26.51 Watts; higher compressor exergetic defect of 0.03, 0.03, 0.06 and 0.04 Joule, lower coefficient of performance of 0.06, 0.23, 0.71 and 1.18; and lower exergetic efficiency of 0.012, 0.008, 0.056, 0.062 Joule than R600a, LPG, R6ooaAl2O3, LPGAl2O3. motor compression work of unblended R134a refrigerant is higher than unblended R600a, unblended LPGAl2O3 blended in R600a and LPG by 15.28%, 16.08%, 37.73% and 40.43. All the selected refrigerants met the chill compartment temperature, ISO 8187 compartment standard of -2 ≤ tcc min, max ≤ +3, while R6ooaAl2O3 and LPG Al2O3 nano-refrigerants showed improved compressor characteristics.