In this work, the optimization study of the solar collector integrated, with a thermal energy storage tank for the vapor absorption refrigeration system, was studied using TRNSYS. The performance of the integrated system was evaluated considering major contributing parameters such as solar collector area, the mass flow rate of the operating fluids, storage tank volume and height, absorber plate thickness, tube spacing, absorber tube diameter, insulation thickness, and glass thickness/properties, respectively. A physical model of the complete solar water heating (SWH) and refrigeration system was developed followed by simulation studies of the major components for optimization, and finally, the obtained results were compared with the reported data for validation. The results indicated that, by using the solar power with a serpentine tube type flat plate collector of area 24 m2 and a storage volume to a specific collector area of about 60 Lm−2, the optimized system could meet 65% of the annual thermal energy requirement for the refrigeration unit. Further, the annual performance of the optimized solar collector in terms of collector efficiency, heat removal factor, and overall heat loss coefficient was found to be about 0.32, 0.87, and 2.99 W m−2 K, respectively. In addition, the optimization approach that is adopted using TRNSYS in the present study could be used for optimizing the solar‐based energy system for various applications.