Performance analysis of small capacity absorption chillers by using different modeling methods

• Comparison of four empirically based models: GNA, ΔΔt′, MPR, ANN.
• Experimental data of 12 kW absorption chiller are used for modeling.
• ΔΔt′, MPR, ANN methods are suitable for complex simulation environments.
• The statistical indicators and tests show a slight advantage of the ANN method.

This paper presents a review and comparison of simple, yet accurate steady-state models of small capacity absorption chillers using highly reliable experimental data obtained with an absorption chiller of 12 kW in a state-of-the-art test bench. These models can potentially be used in complete modeling and simulation tools or in supervisory control strategies for air-conditioning systems using absorption chillers.With respect to that, a comparative evaluation of different modeling methods for predicting the absorption chiller performance is presented. Four empirically based models: the adapted Gordon-Ng model (GNA), the characteristic equation model (ΔΔt′), the multivariable polynomial model (MPR) and the artificial neural networks model (ANN) were applied using the experimental data and thoroughly examined. The paper also presents statistical indicators and tests which might assist in selection of the most appropriate model.The excellent statistical indicators such as coefficient of determination (>0.99) and coefficient of variation (<5%) clearly indicate that it is possible to develop highly accurate empirical models by using only the variables of external water circuits as model input parameters.