L. G. Limpus (lglimpus@coastnet.com)
Thu, 10 Jun 1999 21:42:44 -0700
Dear Coleagues,
With regard to the use of ice on fish boats and Andrew Strak's comment that
there is no difference between various types of ice, and other comments
that a lot of work was done a number of years ago, I remembered a quote
from Gordon Eddie (formarly with the White Fish Authority in England) in an
old FAO Technical paper No: 232 "Road transport of fish and fishery
products", in which he makes the following statement:
"---However, it should be noted that, in practice, the refregerating effect
of crushed ice is never as high as 80 kcal/kg, unless the ice is
sub-cooled, for the simple reason that commercial crushed ice is always
wet, that is, it is a mixture of ice and water. A more realistic figure is
67 kcal/kg of the misture as purchased."
>
>There is no difference between various types of ice concerning their
>enthalpy or heat content. However, any finer ice of a larger surface such as
>flake ice will be cooling your catch faster but will also melt faster giving
>some impresion that it is not so 'cold' as slow melting one due to a lower
>surface/volume ratio for ice cubes. Please also remeber that almost 100% of
>the cooling 'power' of the ice comes from its melting action where it
>absorbs 80 cal/g still being at OC and that is equivalent to raising
>temperature of 1 g of water from 0C to +80C. The specific heat of ice is a
>relatively low though, and if you have some freshly made ice at -30C it will
>need only 13 cal/g to be raised to the temperature OC.
>
>Best regards,
>
>Andrew Strak
>
>
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