Transport refrigeration units are in widespread use and are vital to global logistical infrastructure. In their most common form they are diesel powered but these units face an uncertain future with the upcoming introduction of low emission zones in major cities such as Paris and London. Although going largely unnoticed an alternative unit described as an open cycle CO2 system has been available that does not require diesel power and can freely enter low emission zones. In this dissertation, such a system is examined experimentally and modelled for the first time in literature, using the switched moving boundary technique. An experimental system is developed on which both static and dynamic tests are performed. Measurements are taken of the relevant air and refrigerant temperatures, the refrigerant pressures, the mass flow rate of CO2 and the cooling capacity of the system. A method of measuring the two-phase zone length within the evaporator coil with temperature measurements along the length of the coil is presented. The utility and efficiency of the system are examined in detail using the above measurements. The superheat control is identified as an issue. A switched moving boundary model is adapted to work with an open cycle CO2 system and refined using the static and dynamic pull-down results from the experimental testing. Additions to the base model include a superheated only representation in the evaporator, the use of a dynamic link library (DLL) to call fluid property routines, a model of the back pressure regulator, the addition of pressure drop into the evaporator model and a new calculation for the refrigerant outlet temperature. The final model is validated against typical customer operating modes at both a fresh set-point of 0°C and a frozen set-point of -25°C. In general good correlation between the experimental results and the model outputs are seen with the exception being the periods where the EEV is closed in cycle sentry control with fans off. The model is subsequently used to design new control parameters for superheat control with good results.