四、請簡述真空沸騰式海水淡化裝置的工作原理及優點。（20 分）

⑵ The fresh water cooling system is a closed cooling system, in which the fresh water first passes the fresh water cooler, where it is cooled by sea water, and then is circulated through the cooling water jackets of the main engine by fresh water pump to cool cylinder liners, cylinder heads and exhaust valves.