3.1.4 Latent heat

3.1.4 Latent heat

It is the quantity of heat required to change the state or condition or phase under which a substance exists without change in temp. Eg. a definite quantity of heat must be transferred to ice at OOC to change it to water at the same temperature. This definite quantity of heat is known as latent heat of fusion of water/ice.

Latent Heat of fusion of ice/water = 79.7 cal/g or 80 cal/g

It is also expressed in terms of BTU/lb

1 BTU/lb = 0.5556 kcal/kg or/k cal/kg = 1.80 BTU/lb

Latent heat of fusion of any food can be calculated if its water content is known.

Latent heat = 80X% water in food

                         --------------------------

                                    100

Latent heat of fusion of some food stuffs.

Food Product       

Latent Heat of fusion

BTU/lb 

 kcal/kg

Eggs 100  55.56
Fish 101 56
Green peas  106  58.88
Milk 124  68.85
Oyster meat   125  69.44
Pork  86 47.77
Water  144  80

Last modified: Saturday, 24 December 2011, 11:03 AM