As I’ve had use of this in the past I am putting it here for future reference.

PI = (V/1000) * DCD * 43.75

Where:
PI = Pounds of ice required
V = Volume of water in gallons
DCD = Degrees Cooling Desired; Current – Desired temp in °F

Note: Not sure where the 43.75 constant comes from. Will update if/when I find a source.

Note 2: This is of interest and could be used to rework the above formula: http://www.hk-phy.org/contextual/heat/cha/la_he07_e.html

Published on September 3, 2019