Standalone and self-contained cooling systems using compressed liquid and/or gas CO2 containers positioned in an insulated or non-insulated vessel and consisting of a specially designed unit where the containers are vertically positioned in an upright or upside-down position.The liquid and/or gas CO2 coolant is then released into capillary tube(s) embedded into a heat transfer plate or heat exchanger thus leveraging the CO2 coolant properties.The temperature is controlled by a metering CO2 releasing system encompassing an electronic control device which can be operated remotely and/or via a touch screen and which sends alerts when pre-defined thresholds are exceeded.The invention's metering CO2 releasing system may be triggered by an electronic or a thermostatic valve or may be triggered manually or by an electronic solenoid. The invention's cooling system also encompasses check valves, which avoid liquid and/or gas CO2 from escaping when removing or replacing CO2 containers individually.