Final answer:
An ice maker uses ammonia as a working fluid to convert liquid water to ice by cooling the water from +15°C to -10°C.
Step-by-step explanation:
The ice maker uses ammonia as a working fluid to convert liquid water to ice. The process involves cooling the water from a temperature of +15°C to -10°C. This is achieved by extracting heat from the water using the ammonia as a coolant. As the water cools, it freezes and forms ice.