This article aims to analyze comparatively the performance of a combined refrigeration system consists of an upper section (adsorption chiller) and a lower section (vapor compression chiller (VCC)). The arrangement of the adsorption cooling chiller (ACC) depends on two adsorption beds that use silica gel/water as a working pair. The beds are driven by heat comes from outside heat sources with low-grade temperatures <= 100 degrees C. Whereas in the bottom section, different types of refrigerants (R410A, R152A, R1234yf, R1270, and R32) have been utilized to be driven by the mechanical compressor. This paper focuses on the evaluation of the refrigerants in VCC and the working pair in ACC by means of coefficient of performance (COP) and energy-saving ratio (ES) in this refrigeration system. The computed results reveal that the refrigerants show the same behavior while calculating the COP of the combined system and the VCC in the combined system, with the high values reached up to 0.5 and 8.8 for R152A, respectively. Meanwhile, the energy-saving reached up to 65.3%. The increase ratio (IR) of the COP of the VCC is also calculated with the highest value reached up to 188%. The effects of the ambient air temperature, the heat source temperature, the cycle time and the evaporation temperature on the system performance and the required mass of adsorbent in the adsorption beds are investigated for the design of ACC-VCC combined system.