Implementation of the Characteristic Equation Method applied to an Absorption Chiller LiBr/H2O of Commercial type

Alvaro Antonio Ochoa, José Ângelo Costa, Sérgio Da Silva Franco


This study aims to obtain the characteristic equation of a single effect absorption chiller of commercial type (WFC-SC10) of 35 kW of cooling capacity and that uses the pair LiBr/H2O as work fluid, from the nominal data and characteristics of the thermal components. The absorption chiller studied consists of five main components; generator, condenser, evaporator, absorber and a solution heat exchanger. The characteristic equation method is based on the Duhring equation that allows correlate the internal average temperatures of the heat exchangers of the absorption chiller as a function of the characteristic parameters (product AU, flow rates and temperatures of cold, hot and chilled water circuits). The thermal activation power (generator) and the cooling capacity (evaporator) of the chiller were found from the same operating data and for the entire temperature range of cold water circuits (29-32°C), hot water (75-95°C) and chilled water (7-13°C). The versatility of the thermal power activation and the cooling capacity was verified by comparing the results obtained by theoretical simulation of the absorption chiller and the results calculated by the implementation of the characteristic equation method. The errors shown in the comparison were lower than 5%.


Absorption Chiller; LiBr/H2O; Characteristic equation.

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