1. The problem statement, all variables and given/known data a) Assume that a Carnot cycle is used to achieve that 250kg of water at 0 degrees celsius is frozen into ice using an ideal refigerator The room temperature is 27 degrees. What is the minimum amount of work input to the refrigerator to achieve this? b)Assume the refigerator works with 65% efficiency (compare to a carnot engine), how much work input does it require. 2. Relevant equations Latent heat of melting ice =3.33E5 J/kg 3. The attempt at a solution For part a) I don't see why the amount of work input is not just that required to turn the water to ice, which would be 3.33E5*250. I think I might be missing something as the room temperature is given. I haven't yet started the second part as I think I need to understand the first part. Any help would be appreciated.