12. Some useful facts about water and ice

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Properties of water and ice

Properties Metric Units Remarks
Pure water
Density at 15C 1 kg/l
1 t/m
Pure water becomes denser as the temperature falls, until at 4C it is at its densest, ie 1 kg/l.
For practical ice-making calculations, the density of water can safely be assumed to be 1 kg.1
Specific heat 1.0 kcal/kgC
Latent heat of fusion 80 kcal/kg
Thermal conductivity
(at 10C)
0.5 kcal/mhC
Freezing point 0C
Boiling point 100C  
Sea water
Density 1.027 kg/l At 0C and salinity of 3.5%.
1.027 t/m
Specific heat 0.94 kcal/kgC At 0C
0.93 kcal/kgC At 20C
Latent heat of fusion 77-80 kcal/kg Approximate values at salinities of up to 3.5%. Indeterminate owing to presence of salts.
Freezing point at salinity of:   Salinity varies from sea to sea but for practical purposes the world average of 3.5% is
sufficiently accurate.
1.0% -0.6C
2.0% -1.2C
3.0% -1.6C
3.5% -1.9C
4.0% -2.2C  
Ice
Density    
Freshwater ice 0.92 kg/l At 0C
0.92 t/m
Seawater ice 0.86-0.92 t/m Depending on salinity and amount of trapped air.
Specific heat:   For calculating the amount of ice to use on fish, a value of 0.5 is sufficiently accurate. Specific heat of seawater ice can be very much higher near to melting point.
0C 0.49
-20C 0.46
Latent heat of melting 80 kcal/kg  
Thermal conductivity: kcal/mhC  
0C 1.91
-10C 1.99
-20C 2.08
Melting point 0C Melting point of seawater ice is indeterminate, since salt content is rarely uniform throughout the ice, but should on average be about -2C.
Stowage rates m/t  
Block ice in blocks 1.4
Crushed block ice 1.4-1.5
Flake ice 2.2-2.3
Tube ice 1.6-2.0
Plate ice 1.7-1.8

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