The refrigerator

1. It’s a refrigerator... Your argument is invalid- James Yoo The refrigerator

2. James Harrison • James Harrison (April 1816 - 3 September 1893) was a Scottish born Australian pioneer in the field of mechanical refrigeration. He was also a newspaper printer, journalist , and politician • Yea he’s the guy in the bottom right corner

3. The Refrigerator • The refrigerator is often a product that is easily looked over, but it’s existence has a huge impact on our society. • Simply put, the refrigerator cools and freezes things (normally food) down, and in doing so, slows down the growth of bacteria.

4. The First refrigerator • Harrison's “refrigerator” began operation in 1851 in Geelong. His first commercial ice-making machine followed in 1854, and his rights for an ether vapor-compression refrigeration system was granted in 1855. This “new” system used a compressor to force the refrigeration gas to pass through a condenser, where it cooled down and liquefied. The liquefied gas then circulated through the refrigeration coils and vaporized again, cooling down the surrounding system. The machine employed a 5 m (16 ft.) flywheel and produced 3,000 kilograms (6,600 lb) of ice per day

5. Recent refrigerators • Nowadays, the physical design, efficiency and marketing of the refrigerator has changed greatly. • The first refrigerator was more of an ice generator than a place where you could store food.

6. In the refrigerator, there are three gases and liquids involved • Ammonia (A gas with a boiling point of -33°C at room temperature, but is pressurized to a point where it is liquid), Hydrogen gas, Water. • These refrigerators use ammonia as their refrigerant, assisted by water and hydrogen to cycle the ammonia. The refrigerator has five main components, refer to left: • Generator - generates ammonia gas • Separator - separates ammonia gas from water • Condenser - hot ammonia gas is cooled and condensed to create liquid ammonia • Evaporator - liquid ammonia evaporates removing heat from cabinet. • Absorber - water absorbs ammonia gas. • The cooling cycle starts with liquefied ammonia entering the evaporator at room temperature. The ammonia is mixed in the evaporator with hydrogen, regulating the total pressure, which in turn regulates the vapour pressure, reaching the boiling point of the ammonia. The ammonia boils in the evaporator, providing the cooling required. • The next three steps exist to separate the gaseous ammonia and the hydrogen. First, in the absorber, the mixture of gasses enters the bottom of tubes that go up, into which water is added at the top. The ammonia dissolves in the water, producing a mixture of ammonia solution and hydrogen. The hydrogen is collected at the top of the absorber, with the ammonia solution collected at the bottom. • The second step separates the ammonia and water. In the generator, heat is applied to the solution, distilling the ammonia from the water. Some water remains with the ammonia, in the form of vapour and bubbles. This is dried in the final separation step, called the separator, by passing it through pipes with small obstacles to pop the bubbles, allowing the collected water to drain back to the generator. • Finally the pure ammonia gas enters the condenser. In this heat exchanger, the hot ammonia gas is cooled to room temperature and hence condenses to a liquid, allowing the cycle to restart.  

7. Yeah~ • Thankyou...