How much energy must be removed from a 450 g block of ice to cool it from 0∘c to - 20 ∘c?

The energy removed from a 450 g block of ice can only be done with a few options: a colder freezing facility, liquid nitrogen, or stopping the energy at all and adding dry ice for a brief period. The 450 g block should loose heat energy faster in a thermostat set at - 20 degrees just to maintain the ice formation.