If I were going to be making two longhaul flights in Y, I'd give serious consideration to the day room at the Sheraton. The standard day rate (08:00 until 18:00) is €139,- (VAT included).
In calculating the cost, keep in mind that you'll save the €8 you would have spent on checking the carry-on at the Left Luggage office. You'll be able to have a long sleep and a refreshing shower before continuing your journey.