What is Dry ice Refrigeration? Advantages, Disadvantages and Applications

In this refrigeration method, solid carbon dioxide is used. Solid carbon dioxide is called as Dry ice.
It has the characteristics of changing from solid to vapour state directly without entering into the liquid phase. During this transfer, the dry ice absorbs heat equivalent to its latent heat of evaporation.

It evaporates at -78.3°c at standard atmospheric pressure.
The dry ice is placed on top or at sides of cartons containing eatables, etc. When this dry ice sublimates it will absorb heat from the food stuff in the cartons or containers by keeping them in frozen condition.

The solid carbon dioxide can be pressed into various sizes and shapes. while absorbing the heat, it changes directly from solid to vapour and does not go into liquid state. The figure shows the production of solid carbon dioxide.

The carbon dioxide vapour is compressed to high pressure and high-temperature vapours using a compressor. Then it is condensed to high-pressure liquid CO2 in the condenser. High-pressure liquid CO2 is made to pass through the expansion value.
During expansion, the pressure drops below triple point and a mixture of solid and vapour CO2 is received in the snow chamber.
The solid CO2 in the form of snow is removed and compressed by mechanical means to form CO2 cakes.
The vapour CO2 is mixed with make-up CO2 and once again the process repeats.
During the change of state from solid to vapour in the application areas, the dry ice absorbs heat equivalent to its latent heat of evaporation.

Sublimation: It is a process by which a substance changes from solid to vapour without entering liquid state.

Triple point: The only state at which the solid, liquid and vapour phases coexist in equilibrium.

Charles Thilorier is the first person to publish observations about dry ice in 1835.
Compared to water dry ice has heavier density and gravity.
We have seen the smoky effect at parties and concerts, these effects can be done by dry ice.