Previous - Next
12. Some useful facts about water and ice
Properties of water and ice
| Properties | Metric Units | Remarks |
| Pure water | ||
| Density at 15°C | 1 kg/l 1 t/m³ |
Pure
water becomes denser as the temperature falls, until at
4°C 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/kg°C | |
| Latent heat of fusion | 80 kcal/kg | |
| Thermal conductivity (at 10°C) |
0.5 kcal/mh°C | |
| Freezing point | 0°C | |
| Boiling point | 100°C | |
| Sea water | ||
| Density | 1.027 kg/l | At 0°C and salinity of 3.5%. |
| 1.027 t/m³ | ||
| Specific heat | 0.94 kcal/kg°C | At 0°C |
| 0.93 kcal/kg°C | At 20°C | |
| 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% | -0.6°C | |
| 2.0% | -1.2°C | |
| 3.0% | -1.6°C | |
| 3.5% | -1.9°C | |
| 4.0% | -2.2°C | |
| Ice | ||
| Density | ||
| Freshwater ice | 0.92 kg/l | At 0°C |
| 0.92 t/m³ | ||
| Seawater ice | 0.86-0.92 t/m³ | 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. | |
| 0°C | 0.49 | |
| -20°C | 0.46 | |
| Latent heat of melting | 80 kcal/kg | |
| Thermal conductivity: | kcal/mh°C | |
| 0°C | 1.91 | |
| -10°C | 1.99 | |
| -20°C | 2.08 | |
| Melting point | 0°C | Melting point of seawater ice is indeterminate, since salt content is rarely uniform throughout the ice, but should on average be about -2°C. |
| Stowage rates | m³/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 | |