a refrigerator moves heat from cold to warm. why does this not violate the second law of thermodynamics?

Answer 1

First Law

Remember that the First Law of Thermodynamics is really a restatement of the Principle of Conservation of Energy, which for the refrigerator became

QC + W = QH

Second Law

The Second Law of Thermodynamics can be stated in many ways, but for the refrigerator its simplest statement is

Heat, by itself, will always pass from a hot object to a cold object

In the case of the refrigerator the cold object is the inside of the refrigerator (including its contents) and the hot object is the outside air of the kitchen.

So how does this apply to refrigerators?

The Second Law states that, since heat always flows from hot to cold, it won't flow out of the cold refrigerator into the warm room of its own accord, then it must be made to do so, that is we must do some work and W in the above equation cannot be equal to zero. This gives us another way of writing the Second Law.

Heat cannot be transferred from a cold object to a hot object without the use of some work.

http://physics.csustan.edu/HowThingsWork/Topics/Refrigerator/Law2.htm

Answer 2

You have voiced several misconceptions here. First of all, heat always moves from where there is more of it to where there is less of it. Second, there is no such thing as "cold" in that coldness is not a form of either matter or energy. A cold object is simply one that has less heat. Therefore heat always moves from hot objects to cold objects - not vice versa. Now, as to how a refrigerator works, briefly. It takes heat energy to change a liquid to a gas or to cause a gas to expand. Agreed? Look at it the other way around. If a gas expands for any reason it soaks up heat like a sponge. This is why the CO2 cartridge feels cold after you shoot a paintball gun. The object it absorbs that heat from now has less heat so by definition it is colder. That basically is how a fridge works. Freon, or some alternative gas is circulated around the food in closed pipes and allowed to expand. It soaks up heat from the food like a sponge soaks up water. Now. The heat filled gas goes to the electric motor (remember this) driven compressor where it is compressed and the heat is squeezed out like compressing a water filled sponge releases the water. A fan blows this heat (which originally came from your food) out the back of the appliance. Feel behind your fridge - notice the warm air? Now the compressed gas goes back to the cooling coils in the freezer section to start the cycle over again. As to why this whole process does not violate the 2nd law or the law of conservation of energy, the process does not take place automatically. Go back to the point I said "remember this" in parentheses. The two words just before that were, "electric motor". The laws you are referring to say that an object will roll downhill. But not if you exert a greater force to push it uphill. In the case of the refrigerator the greater force comes from the electric company and before that from the sun and its nuclear fusion but that's a different story.

Answer 3

Because a long time ago, about 10,000 refrigerators filed a class action lawsuit, and the Supreme Court found the second law of thermodynamics to be unconstitutional.

Answer 4

A refrigerator is the main suitable occasion for instance the 2nd regulation of thermo dynamics. Clausius fact of 2nd regulation of thermodynamics is: it particularly is impossible for a self performing mechanism UNAIDED by employing an exterior enterprise to flow warmth from a chilly physique to a warm physique. explanation of the above fact is: The organic means of warmth is to bypass from warm physique to chilly physique. To flow warmth from a chilly physique to warm physique an exterior paintings would desire to be carried out. without this exterior paintings warmth won't have the ability to be transferred from a chilly physique to warm physique. while this way of paintings is accomplished on the chilly physique, an element of the paintings is utilized to eliminate some volume of warmth from the chilly physique and to furnish it to the nice and cozy physique. the the rest part of the paintings is readily utilized to warmth the nice and cozy physique. we can't make the 2nd part of the paintings to be equivalent to 0. this is implied in Clausius fact. without providing paintings (electric skill) the refrigerator can't cool an merchandise under the temperature of its ecosystem.

Answer 5

The second law refers to the total entropy of a closed system. 'fridges produce a lot of hot air that has to be included in the accounting.