Fridges have been quietly 'keeping things cool' in the kitchen for over 100 years, and yet most of us barely give them a second thought. Hannah hits the production line with appliance giants Bosch to find the lifeblood at the heart of every fridge and gets a lesson in carrot droop. And she takes a long, cool look at the fridge's history to reveal how a French monk with a flair for chemistry, a 17th century chicken incubator and an explosive invention in Australia created the ultimate chill.