Heat Engines and Refrigerators - with Example Problems

Mini Lectures with Example Problems E1: An auto engine has an efficiency of 18% and produces 22kJ or work per second. How much heat input is required and how much heat is "wasted" per second? E2: A freezer has a COP of 3.1 and uses 200 W of power. How long dies it take to freeze an ice cube tray that contains 500g of water at 0degC?