Subject:- Refrigeration and Air Conditioning

Topic:- Duct Design and Applications

Difficulty:- Low

The working principle of ice plants can be explained in detailed by stepwise. In ice plant the tanks are filled with chilled brine. The brine solution is kept in constant motion by agitators for increasing the heat transfer from the water in the can to chilled brine.

The agitators may be either horizontal or vertical and are operated by means of electric motors but in factory horizontal agitator is use.

The brine temperature is maintained by the refrigeration plant at -10º C to -11ºc.  The high temperature, high pressure ammonia vapours are condensed in a condenser which may be of shell and tube type or evaporative type.The condensed liquid ammonia is collected in the receiver and then expanded through the expansion valve.

Due to the expansion, the pressure of the liquid ammonia is considerably reduced It then passes through the evaporator coils surrounding a brine tank in which brine solution is filled.

The low pressure liquid ammonia absorbs heat from the brine the brine solution, equivalent to its latent heat of vaporization, gets converted to vapour state and is once again fed to compressor to complete the cycle. The depth of brine tank is such that the brine level is around 25 mm higher than the water level in the cans.

The Tank is insulated on all the four sides and from the bottom.The insulated wooden lids are provided to cover the top in segments, to facilitate the removal of ice cans.

The ice cans are fabricated from galvanized steel sheets and are given chromium treatment to prevent corrosion.

In order to get transparent ice, water in the can is agitated by the use of low pressure air through the tubes suspended from the top. Due to agitation, the dissolved impurities such as salt, even colors get collected in the unfrozen water core.

It is desirable that it should be taken out and replaced with fresh water. Applications:The applications of an ice plant are in Fisheries, Hospital, Chemical Pharmaceutical and Commercially used in different industrial applications etc.