Carbon dioxide (CO2 /LCO2)
Carbon dioxide is increasingly used as a refrigerant. Particularly popular are supermarket refrigeration and industrial refrigeration systems. CO2 is used in different forms, subcritical in cascade systems, transcritical in pure CO2 systems or as a secondary fluid.
ADVANTAGES AND DISADVANTAGES
The advantages of carbon dioxide are high environmental compatibility (natural refrigerant) the particularly good heat transfer coefficient and a low compression-to-pressure ratio. Due to the significantly better ratio compared to ammonia, the volumetric efficiency is higher which means that systems can be built more compact. Disadvantages are the proximity of the operating range at the triple point and critical point, as well as the high operating pressures required for efficient operation. The high pressure requirements lead to high system costs.
PROPERTIES
- R744
- Global Warming Potential (GWP): 1
- Density (0 °C): 927.4 kg/m3
- Spec. heat (0 °C): 2.542 kJ/kgK
- Vapor pressure (0 °C): 3.485 Mpa / 500 psia
