Performance analysis of an integrated adsorption and absorption refrigeration system

In this study, a completely new integrated adsorption–absorption (AD–AB) refrigeration system driven by low-grade heat sources was proposed. A lumped-parameter thermodynamic model was developed to evaluate the performance of this novel system. This model was first validated with data available in the literature and then used to compare the performance between the proposed system and a conventional adsorption refrigeration system. The effect of operating conditions (e.g. heat source and cooling source temperatures) on the Coefficient of Performance (COP) and cooling capacity (CC) was evaluated. The results showed that the CC and COP of the proposed system were as high as 13.7 kW and 0.4, respectively at a thermal source temperature of 60 °C. The COP of the integrated system was significantly higher compared to the conventional adsorption system at heat source temperatures below 65 °C. The cooling capacity of the integrated system was increased by up to 100% as compared with a conventional adsorption system under the same operating conditions. It was also found that the COP of the proposed system did not change significantly at heat source temperatures between 50 and 85 °C. This indicated the integrated AD–AB system could work efficiently across a wide range of low-temperature heat sources. Furthermore, the results also indicated that the COP of the integrated system was largely affected by the cooling water inlet temperature if the heat source temperature was lower than 55 °C.