Here is how the law works....
Wine and cider may not be frozen for the express purpose of increasing the alcohol content. TTB has previously held that freezing a mixture of alcohol and aqueous fermented material, like wine, causes some water to freeze and separate from the alcohol mixture. The resultant mixture has higher alcohol content than the original and is called a “high alcohol content wine fraction” and any person who separates alcoholic spirits from any fermented substance is known as a distiller. Because Federal law requires a permit to operate as a distiller and prohibits the operation of a distillery in a residence, in order to freeze wine or cider you will have to file an application with TTB and follow our regulations regarding the manufacturing processes approved for making distilled spirits.
In short, as far as the government is concerned, performing Fractional crystallization is considered the same as distillation.