The application of carbon dioxide to small industrial refrigeration systems.

Significant effort is being applied to the improvement of efficiency in transcritical carbon dioxide refrigeration and heat pump systems, particularly for higher ambient temperatures. The system configuration known as the low pressure receiver (LPR) is particularly well suited to this application and can be arranged for single stage or two-stage operation. This paper examines the LPR system as used in carbon dioxide systems and compares this with other methods of applying carbon dioxide, and with a standard R-404A DX system which has been the standard solution for this application for many years. The paper provides some calculated values for the different systems under discussion and then discusses performance figures from installed systems to verify the calculations. The parameters considered in the study include efficiency, reliability, simplicity, maintainability and the likely degradation of performance over time (a factor which is usually ignored when comparing and contrasting systems). Capital cost and opportunities for future development are also examined.