Dynamic testing and modeling of a diffusion absorption refrigeration system

• Experimental tests on a domestic diffusion absorption refrigerator were performed.
• Dynamic modeling of the refrigerator for different electric heater powers input.
• The black-box technique was used.
• We propose a general model of the refrigerator using a transfer function.

This paper presents experimental investigations and modeling in dynamic or transient mode of a commercial diffusion-absorption refrigerator powered by an electric heater. The instantaneous cooling capacity is experimentally determined for different electric heater inputs. A first order transfer function with delay is found to be an adequate model of the refrigerator behavior for each heat input. The fitting quality of the model ranges between 93% and 97%. The three parameters of the model are expressed in a further step as functions of energy input to the machine in order to construct a generalized model for the machine. The steady state performances of the refrigerator are quite good predicted, with deviations in cooling capacity not exceeding 8%. The proposed generalized model could be very useful for the prediction of the transient behavior of the commercial diffusion-absorption refrigerator.