الفهرس | Only 14 pages are availabe for public view |
Abstract In this work, replacement of R-134a having GWP 1430 by R-1234yf with GWP 4. R-1234yf is tested in an air-conditioning system as a proposed alternative to R-134a. The system is tested at 30, 35, 40, 45 and 50 Hz evaporator fan frequency to cool the air entering to the evaporator section at a fixed temperature of 35ᵒC. The system is charged with 600, 700, 800, 1000 and 1200 g of each refrigerant. The M_charge of 600 and 700 g of R-134a and, the M_charge of 600 g of R-1234yf failed to achieve the safe system operation. The charge mass of 800 grams gives the best performance for both refrigerants. At f_(evap-fan) of 30 Hz, the system gives the best results for both refrigerants. All the previous tests are repeated with and without the use of the LSHX Using LSHX reduces the COP, and η_2nd law by around 5.94%, and 22.4%, respectively, for R-1234yf. The same applies for R-134a. Also, R-1234yf has higher COPsys, and, second law efficiency, and lower compressor power consumption. Both refrigerants operate at a moderate range of compressor discharge temperature of 85ᵒC. Keywords: Refrigeration; hydrocarbons; efficiency; environmental concerns. |