Executive Summary : | Absorption refrigeration systems (ARs) play an important role in energy saving and pollution reduction as they use low-grade energy such as waste heat and solar energy to produce cooling effect and use environmentally friendly refrigerants like water and ammonia. several research works have demonstrated that exhaust gas of internal combustion engines, exhaust heat of fishing vessels, and industrial waste heat can be considered as heat sources for ARs. But to compete with vapour compression refrigeration system, size of the ARs should be reduced and the coefficient of performance (COP) should be improved. Recent research works propose the use of NH3 or LiNO3 mixture as the working fluid to achieve these goals. Elimination of rectifier makes NH3 or LiNO3 ARs suitable for small scale applications, such as automobile refrigeration unit using exhaust heat as input energy. Low operating temperature in the generator makes it a viable option for solar cooling. Theoretical simulations on NH3 or LiNO3 ARs have proved that it can achieve evaporator temperature below 0°C, which manifest its use in the freezing applications. But the experimental results did not match the theoretical findings because of higher viscosity of NH3 or LiNO3 solution. Thus, in order to reduce the viscosity, it was proposed to add suitable amount of water to the binary solution NH3 or LiNO3 solution. The thermophysical properties of ternary namely, solubility, viscosity, density, vapour pressure heat capacity, vapour liquid equilibrium, thermal conductivity are available in literature. There are reports on the theoretical simulation and experimental investigation of ARs with NH3 or (LiNO3+H2O) solution as working fluid. However, literature on boiling heat transfer coefficient (BHTC) and pressure drop of this mixture is very limited. Hence the present study focuses on measurement of BHTC and pressure drop of NH3 or (LiNO3+H2O) mixture at different water mass fractions. The experiments will be conducted with plate heat exchanger (PHE) as the generator of the ARs. Effect of various parameters such as heat flux, mass flux, water mass fraction, vapour fraction on BHTC and pressure drop will be evaluated. |