| Abstract [eng] |
This work analyses what happens when the refrigerant in a vapour-compression chiller is replaced with a lower-GWP alternative. I built a single-stage vapour-compression cycle model in Python using CoolProp 7.2.0 and used it to compare thirteen refrigerants from four phase-out groups at the same operating conditions (-10 °C evaporation / +40 °C condensation). For every banned or phasing-out refrigerant in the study there is at least one approved low-GWP replacement. The main results are: R32 gives the best mix of COP (4.61) and volumetric cooling capacity (6,237 kJ/m3) for new R410A-class equipment; R448A and R449A work as close drop-in replacements for R404A in commercial refrigeration and cut GWP by 78-79%; and R1234yf has the lowest direct climate impact for centrifugal chiller use. Annual bin-method analysis for the Vilnius climate (LHMT 1991–2020 normals) shows that the seasonal efficiency penalty of switching from R410A to R32 is approximately 3–5%, while the TEWI reduction over a 15-year system lifetime reaches 2 tonnes CO₂eq. For the R404A→R448A transition in commercial refrigeration, the TEWI reduction exceeds 30 tonnes CO₂eq over the same period. A practical component recalculation case study (Chapter 5) confirms pressure compatibility and quantifies required adjustments for compressor, evaporator, and condenser sizing. |
