Effect of the NH3–LiNO3 concentration and pressure in a fog-jet spray adiabatic absorber

This paper presents the effect that both the ammonia concentration in an ammonia–lithium nitrate solution and the absorber pressure have on the adiabatic absorption of ammonia vapour by droplets generated by a fog-jet injector. The injector ensemble is located at 205 mm from the bottom of the absorber. The solution has an ammonia mass fraction varying from 0.419 to 0.586 and the absorber pressure varies from 429 to 945 kPa. This is representative of the operating conditions for conventional absorption chiller cycles, but also for advanced cycles such as those with a booster compressor located in series between evaporator and absorber. This leads to a higher than common pressure in the absorber. Results show approach to equilibrium factors higher than 0.83, being the mean value of the experiments 0.9. The absorption ratio obtained was between 0.008 and 0.07. The increase in pressure and inlet subcooling increases the absorption rate, whilst the increase in the ammonia mass fraction increases the approach to equilibrium factor, decreasing the absorption rate.

► Experimental study of spray adiabatic absorber using fog-jet injectors.
► NH3–LiNO3 as absorbent reporting a wide range of pressures and concentrations.
► Approach to equilibrium factor always higher than 0.83 and an average of 0.9.
► Absorption ratio up to 0.07, increasing with pressure, decreasing with concentration.
► For every pressure the approach factor increases linearly with inlet subcooling.