Construction and working of an Ice Plant


This resource will make you familiar with how big-sized 'Ice plates' are manufactured. This ice-making process involves heat transfer/extraction from the water with the help of basic refrigeration techniques. This ice plant uses 'brine' and 'Ammonia' as refrigerants, and working medium alternatively.

The function of an ice plant or ice factory is to make or form ice in large quantities and in large sizes. The ice-making process is quite similar to the one we observe in a domestic refrigerator. The only difference lies in the ice-making stage. In the freezer compartment, the tray with water when it comes in contact with the very low-temperature environment becomes ice but in an ice plant which is a huge commercial factory, it uses separate ice making or ice freezing circuits. The cold is produced in one circuit using a vapor compression refrigeration cycle and it is transferred to the water cans by another circuit by secondary refrigerants.

  • Ammonia: It is the primary refrigerant that takes heat from brine and gives it to the primary circuit. This ammonia changes phase while moving in the circuit
  • Brine: It is the secondary refrigerant that takes heat from the water and produces ice. Brine can be of either NaCl or CaCl2

Circuits in ice plant

  1. Refrigeration circuit: Ammonia, a primary refrigerant as a working medium that actually produces the cold by changing its phase at different locations
  2. Cooling water circuit: Cooling water as a working medium to remove the heat of compression and cooling loads
  3. Brine circuit: Brine solution - secondary refrigerant as working medium that transfers the cold from ammonia to water-filled cans where ice is to be formed.

Construction and working of

Construction of ice plant

  • Compressor: Its function is to increase the temperature and pressure of Ammonia vapor coming out from evaporator. The boiling point of ammonia increases as the pressure gets increased in the compressor. This high boiling point ammonia is now ready to release the heat in form of condensation at condenser
  • Condenser: It liquefies the high-pressure and high-temperature Ammonia to high-pressure and high-temperature Ammonia. Here chilled water (3rd circuit) comes in contact with the high-pressure and high-temperature ammonia and provides the temperature for condensation. The heated water is pumped and again taken to the circuit after it has been cooled at the natural cooling tower
  • Receiver: It is used to collect the liquid Ammonia from the condenser.
  • Throttle Valve: It expands Ammonia coming out from the receiver to low pressure.
  • Evaporator: It vaporizes the liquid Ammonia from the throttle valve by extracting heat from 'brine' and hence brine gets cooled and this brine solution is recirculated to a water tank containing 'ice cans filled with water to absorb the heat of the water to freeze it and make ice.

Working of ice plant

  • Low pressure and low-temperature Ammonia coming out from the throttle valve is vaporized by taking the latent heat from the brine. Hence brine gets cooled which is circulated in the brine circuit to freeze the water and form ice water.
  • This cooled brine further absorbs the heat from the water and converts water to ice.
  • Vaporized Ammonia is compressed to high pressure and temperature and passes from the condenser.
  • In a condenser Ammonia is condensed by water circulated in a cooling water circuit having a natural cooling tower. The condenser condenses the Ammonia with water coming from the natural cooling tower.

Read also about How does 'cold storage plant' work

Conclusion

Ice plant is a big size domestic refrigerator freezer. The working principle of ice making is the same as that of the domestic refrigerator but the ice making is done by taking heat from water using a brine solution and this water now gets converted into ice.


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Comments

Guest Author: Gino08 Jun 2014

Is it only Ammonia that can be use as refrigerant in this type of Ice plant?

Guest Author: AbdulQadir03 May 2020

Can you please make a correction? Actually it should be high pressure and high-temperature vapour refrigerant that comes into the compressor from the evaporator and not low pressure and low-temperature as mentioned herein.



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