Compressed CO₂ Refrigeration for Energy Storage and CO₂ Utilization

In this paper, we present a simple analysis to explore the possibility of using compressed CO₂ for air-cooling applications based on its Joule-Thomson cooling capability. In the analysis, gaseous CO₂ stored in a high-pressure compressed tank is allowed to expand into a low-pressure heat exchanger having multiple flow paths. Two flow configurations (parallel and counter flows) are used. Five different values (1–5 MPa) for the pressure of the compressed tank are used, while the pressure of the heat exchanger is kept constant at 0.1 MPa. While keeping the dimensions of the flow path (thickness = 2 cm, width = 10 cm, length = 1 m) unchanged, the total heat transfer, exit air, and CO₂ temperatures are calculated. The results show that these depend significantly on the compressed tank pressure, the number of the flow paths, and air mass flow rates. When the pressure of the compressed tank is 5 MPa, our results indicate that the Joule-Thomson cooling capability of CO₂ expansion can effectively generate a cooling power from 3 to 4 kW in the heat exchanger, and a stream of 124 g/s of hot air flowing through it can have a temperature drop from 25 to 30 °C.