Energy storage has become a matter of great concern in the increasing Renewable Energy (RE) scenario and it plays a vital role in the renewable based micro and nano grids. Among the various energy storage systems, Compressed Air Energy Storage (CAES) system has received the attention of scientists during the recent years due to its long life cycle and the scope and potential of increasing roundtrip efficiency by introducing the concept of polygeneration along with other recent inventions in this technology. In the present work, an experimental investigation has been carried out on small capacity CAES system by constructing a 400 L capacity storage tank and the round trip efficiency is quantified by conducting several charging and discharging experiments. The results reveal that the expander efficiency is 41.79%, 54.25% and 68.3% for the mass flow rates of 0.005 kg/s, 0.0075 kg/s and 0.01 kg/s respectively and the roundtrip efficiency was 13.4%, 17.4% and 22.02% for the mass flow rates of 0.005 kg/s, 0.0075 kg/s and 0.01 kg/s respectively. © 2018 Elsevier Ltd