Performance analysis of type 1 and type 2 hybrid absorption heat pump using novel working pairs

In this study, cooling and heating cycle performance analysis is carried out for alternative absorption working fluids using R32, R1234ze (E), and R1234yf, which have gained attention due to regulations on high global warming potential (GWP) refrigerants. The hybrid cycle operates heating and cooling simultaneously because the type 1 and the type 2 cycles are combined sharing the generator and condenser. It is found that the cooling COPs are in the order of R32/DMAC > R32/[hmim][Tf₂N] > R1234ze(E)/[hmim][Tf₂N] > R1234yf/[hmim][Tf₂N]. In the heating mode which occurs in the type 2, the R32/DMAC pair shows the highest COP at the lowest circulation ratio. Therefore, the R32/DMAC pair is selected as the working fluid for the type 1 and type 2 hybrid absorption heat pumps. The conditions of the high temperature absorber are very sensitive to the split ratio. The maximum system COP of 0.617 is achieved when the generator split ratio is 0.80 and the condenser split ratio is 0.96 without the superheating. It is found that the maximum cooling COP is enhanced up to 0.325 and the maximum heating COP is up to 0.562, and it can be used properly for combined heating and cooling systems.