Aligning with the global movements towards mitigating CO2 emissions and regulations to phase out HFC refrigerants, many low GWP refrigerants are being tested and proposed as fourth-generation refrigerants. R1234yf is a refrigerant with a GWP of less than one and has a high potential to replace R134a, which has a GWP of 1300, and it is the most commonly used refrigerant in domestic refrigerators. In this study, an energy performance evaluation and a life cycle climate performance assessment for R1234yf were conducted and compared to those of R134a based on a baseline domestic defrost refrigerators. Four different charges of R1234yf (166.5g, 185g, 202g, and 221g) were tested on three thermostat points (low, medium, and high) and compared with the recommended manufacturer charge of R134a. This study ended up with R1234yf can reduce daily energy consumption by 5 to 2% depending on the thermostat setting. Also, the R1234yf charge optimization to the lowest life cycle CO2 emissions shows that reducing the charge from the baseline value of 185g to 166.5g proves to be the best option. In addition, all R1234yf charges achieved lower evaporation temperature than R134a at all thermostat settings. Also, R1234yf charges were able to achieve similar freezer and refrigerator air temperatures to that of R134a.


School of Sciences and Engineering


Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Graduation Date

Spring 6-17-2021

Submission Date


First Advisor

Mohamed El-Morsi

Second Advisor

Nabil Mahmoud

Third Advisor

Omar Abdelaziz

Committee Member 1

Salah El Haggar

Committee Member 2

Omar Huzayyin


139 p.

Document Type

Master's Thesis

Institutional Review Board (IRB) Approval

Not necessary for this item