A geyser/boiler is used to make the tap water hot. What is the instrument used to cool the tap water ?

When you take a bath, you put on the boiler/geyser and the water turns cold. I want to know if there is any product or instrument by which i can turn the water cold. I have been transferred in the Middle East and the tap water in the summers is as hot as its coming thru a boiler. Help me please.