On the recirculation of ammonia-lithium nitrate in adiabatic absorbers for chillers

R. Ventas (1) , A. Lecuona (1) , Michel Legrand (1) , M.C. Rodríguez-Hidalgo (1)

1 Departamento de Ingeniería Térmica y de Fluidos

This paper presents a numerical model of single-effect absorption cycles with ammonia-lithium nitrate solution as the working pair and incorporating an adiabatic absorber. It is based on - models for separate regions of plate-type heat exchangers and it assumes an approach factor to adiabatic equilibrium. The results are offered as a function of external temperatures. A loop circuit with a heat exchanger upstream the absorber produces subcooling for facilitating absorption process. The effect of the mass flow rate recirculated through the absorber is studied. Results show a diminishing return effect. The value at which the recirculation mass flow yields a reasonable performance is between 4 and 6 times the solution mass flow. With a heat transfer area 6 times smaller than with a conventional diabatic shell-and-tube type absorber, the adiabatic absorber configured with a plate heat exchanger yields a 2% smaller maximum and a 15-20 % smaller cooling power.

Mots clés: Absorption chiller; ammonia-lithium nitrate; adiabatic absorber; mass flow recirculation

Domaines: Thermique [physics.class-ph]; Thermique [physics.class-ph]

R. Ventas, A. Lecuona, Michel Legrand, M.C. Rodríguez-Hidalgo. On the recirculation of ammonia-lithium nitrate in adiabatic absorbers for chillers. Applied Thermal Engineering, 2010, 30 (17-18), pp.2770. ⟨10.1016/j.applthermaleng.2010.08.001⟩. ⟨hal-00678805⟩