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In the summertime, have you ever gotten out of a swimming pool and then felt very cold standing in the sun? That's because the water on your skin is evaporating. The water vapor is carried off by the air, and with it a number of the heat is being removed from your own skin.
That is just like what goes on inside older refrigerators. Rather than water, though, the ice box uses chemicals to complete the cooling.
There are a few things that require to be known for refrigeration.
1. A gasoline cools on expansion.
2. If you have a few things that are different conditions that contact or are near one another, the warmer surface cools and the cooler surface warms up. This can be a law of physics called the Second Law of Thermodynamics.
Old Refrigerators
If you look at the back or base of an older refrigerator, you'll visit a long thin tube that curls back and forth. This tube is linked to a pump, which will be run by an electric motor.
Within the tube is Freon, a type of fuel. Freon could be the brand name of the gas. This gas, chemically is known as Chloro-Flouro-Carbon or CFC. This gas was found to hurt the surroundings when it escapes from refrigerators. So today, other chemicals are utilized in a slightly different process (see next section below).
CFC starts as a fluid. The pump forces the CFC via a large amount of circles in the freezer area. There the chemical turns to a vapor. When it does, it soaks up some of the temperature that could be in the freezer compartment. As it does this, the rings get colder and the fridge begins to obtain colder.
In the part of your refrigerator, you can find fewer rings and a larger room. So, less heat is soaked up by the rings and the CFC steam.
The pump then sucks the CFC as a steam and makes it through pipes which are on the beyond the fridge. By modifying it, the CFC turns back in a fluid and heat is given off and is consumed by the air around it. That's why it could be only a little warmer behind or under your refrigerator.
When the CFC passes through the outside circles, the fluid is ready to return through the freezer and fridge over and over.
Today's Appliances
Modern appliances do not use CFC. As an alternative they use ammonia gas. Ammonia gas becomes a fluid when it is cooled to -27 degrees Fahrenheit (-6.5 degrees Celsius).
A compressor and motor squeezes the ammonia gas. As it is pressurized when it is compressed, a gas gets hot. When you pass the compressed gas through the coils on the back or base of today's icebox, its heat can be lost by the hot ammonia gas to the air in the room.
Remember the law of thermodynamics.
As it cools, the ammonia gas can transform into ammonia water since it is under a top pressure.
The ammonia liquid passes through what's called an expansion valve, a little small opening that the liquid has to squeeze through. Between the valve and the compressor, there is a region as the compressor is pulling the ammonia gas out of this area.
If the liquid ammonia strikes a low pressure area it comes and changes in to a gas. This really is called vaporizing.
Where the cooler ammonia in the coil pulls the warmth out of the spaces the circles then proceed through the fridge and regular part of the refrigerator. This makes the within of the freezer and complete ice box cold.
The cold ammonia gas is sucked up by the compressor, and the gas extends back through exactly the same process over and over.
How Can the Temperature Remain the Same Inside?
A computer device called a thermocouple (it's basically a can sense when the heat in the fridge is as cool as you need it to be. When it reaches that temperature, the system shuts off the energy to the compressor.
Nevertheless the refrigerator is not completely sealed. You will find places, like around the doors and where the pipes go through, that can leak a little bit.
When the cold from inside the refrigerator starts to leak out and the heat leaks in, the thermocouple turns the compressor back to cool the refrigerator off again.
That is why you'll hear your refrigerator compressor motor coming on, running for a while and then turning itself off.
Today's appliances, but, are very energy efficient. Ones offered today use about one-tenth the total amount of energy of people which were built two decades ago. Therefore, when you yourself have an old, old fridge, it's more straightforward to purchase a new one since you'll spend less (and energy) over an extended period of time.
To learn more go to:
Argone National Laboratory - Ask A Scientist ( Hand's 8th Grade Science Site (www.mansfieldct.org/schools/mms/staff/hand/heatrefrig.htm)
How Stuff Works - Fridge (www.howstuffworks.com/refrigerator.htm)
Science Treasure Trove - icebox site (www.education.eth.net/acads/treasure_trove/refrigerator.htm) appliance repair in richmond