or 1674 J
Water is our standard unit of measuring heat energy. The amount of energy it takes to change the temperature of 1 gram of water by 1º C is called a calorie. More formally we would say that the specific heat of water is 1 calorie per gram.
So, 200 grams of water cooled by 20 degrees requires removing 4000 calories.
Since that was over 10 minutes, the amount of heat removed will be just 400 calories per minute.
The more common unit for heat energy is the Joule. 1 calorie is equal to 4.184 Joules.
This answer assumes that the water is in liquid form during this process. If the water approaches 0º C, you will need to consider the latent heat of fusion.