COMPARISON BETWEEN ADIABATIC AND NONADIABATIC ABSORPTION CHILLERS USING AMMONIA-LITHIUM NITRATE AND WATER LITHIUM BROMIDE SOLUTIONS

This work deals with the comparison of the performance of a single-effect absorption chiller using two main configurations: equipped with a nonadiabatic absorber or an adiabatic one. Simulations were developed based on thermodynamic balances, operating with ammonia-lithium nitrate (NH3-LiNO3) and water-lithium bromide (H2O-LiBr) as working pairs. Parameters of evaluation are the coefficient of performance COP, circulation ratio f, and driving heat rate Q(g). Results illustrate that the nonadiabatic absorption system presents better performance parameters for a given operating point, attributable to a higher concentration change in the absorber for a fixed cooling capacity. When the generator temperature T-g is varied, a strong influence on the performance parameters f, Q(g), and COP is observed. However, from a certain value of T-g its variation has a less influence on the performance. When the condenser temperature increases, the COP decreases. The contrary happens if the evaporation temperature is increased. This is valid for both adiabatic and nonadiabatic cases.