Simulación dinamica y comparación de dos sistemas de refrigeracion- absorción amoniaco/agua y agua/bromuro de litio

Abstract

Two simulations of ammonia / water and water / lithium bromide refrigeration systems were carried out comparing them, where the temperature and the mole fraction of the compounds and water in the feed, the reflux ratio, temperature, pressure, the time used, the molar flow were important conditions to take into account to carry out these simulations, the error range is 1.40% with respect to heat and inlet and outlet flows. The coefficient of performance at the established conditions obtained through mathematical calculations are the following: for ammonia / water a coefficient of performance (COP) of 0.29 and water / lithium bromide a COP of 0.15 under stable conditions; this already confirms that there is a reasonable margin between the predicted values and the actual data. And, confirming with the bibliography the ammonia / water system has a higher performance; using a time of 25 minutes, these dynamic simulations increase the ammonia / water cycles as a function of time and, with greater power, the water / lithium bromide cycles. Economically, a cost of $ 0.238 per KWh was obtained in the ammonia / water simulation and a cost of $ 0.060 per KWh in the water / lithium bromide simulation. The system quickly reaches a stable state given the operational parameters for that specification, in the variance between a dynamic and stable simulation it is not much, its values vary by 2% error, in the ammonia / water simulation the error is less, at 19.2 minutes the temperature and pressure become stable, against the simulation water / lithium bromide at 17 minutes seconds it becomes stable. It is recommended to use a thermodynamic pack according to the fluids used.