How do fridges keep things cool?

Answer 1

Refrigerators keep their interiors cool by transferring heat out of the interior of the system to the outside. In reality the total system (the inside of the refrigerator and the room it's in) winds up with more heat but the part we want cold has less heat energy. A bit confusing, but lets step through the process.

A bit of background and a few facts:

• When liquids evaporate they need heat to change to a gas and remove it from their environment.
• When gases are compressed into liquids they increase in heat content.
• When something is hot (like a cup of fresh coffee) it cools off by losing heat to the air around it.
• Some liquids change into gas easily and can be compressed back into liquids easily. Freon and other similar chemical compounds, the liquid in a refrigerator cooling system, is one of these.
• Insulation is used to keep heat from flowing into or out of a volume. The box of the fridge is insulated to prevent heat flow into the volume we want to be cold

Following the freon in the refrigeration and see what happens!

1. Liquid freon is released into the cooling coils in the fridge walls. The liquid expands as it removes heat from the air in the fridge. The air in turn cools the food in the fridge. All the cooling coils are gas tight so no freon escapes into the room.
2. The freon gas is taken from the coils by the compressor system. The gas being removed has more heat than the freon coming in as it has absorbed heat from the fridge air.
3. The compressor reduced the volume of the gas until the pressure is high enough for it to become a liquid. The liquid is relatively warm.
4. The warm liquid flows out of the compressor into the heat exchanger coils. In old fridges these were at the back and looked like a lot of 1/4" tubes with wires holding them in position.
5. Like the cup of hot coffee the warm freon in the exchanger cools down by losing heat to the room.
6. The outlet from the heat exchanger is the discharge of liquid freon discussed in step 1.

So where did this take us. The freon absorbed the heat from inside the heat. It then lost this heat to the room. So the inside of the fridge got cooler and the room got warmer.

Answer:

Heat differs from temperature, a cup of tea has a higher temperature than the Pacific Ocean, however it has incredibly less heat. I.e heat represents the total kinetic energy of the particles, and temperature represents the average kinetic energy.

heat transfers from the body with the higher temperature to the body with the lower temp ( not the one that has lower amount of heat) till both reach equilibrium status.

when we have a certain amount of gas and we pressure it to a smaller volume the average kinetic energy (temperature) increases.

when energy is transfered to a certain object it increases its temperature, however sometimes the energy dedicates it self not to increase the object's temp. rather to change its status e.g from solid to liquid or from liquid to gas.

now the fridge contains what we call freon, when it is liquidated it seeks its original ,gaseous, status, so it absorbs energy from the air inside the fridge so it can free it self. It does not absorb energy from the room because it is insulated.

later the freon is compressed, thus its average kinetic energy (temp) increases, and the thermal equilibrium achieved is disturbed. Note that the total kenetic energy is the same before and after compression.

to achieve equilibrium again the freon shall lose heat to the outside medium (the total K.E is decreased )

then the freon is left free again and its volume increases while its average kenetic energy decreases and thus it shall absorb heat from inside the fridge till equilibrium is achieved , and so on.

Answer 2

"Fridge" is a short name for 'refrigerator'.

It keeps your food cold and fresh....

AKA a temperature regulated cupboard used to store items that rot,

for longer periods of time, without freezing them.

Answer 3

fruit ,vegetables ,any dairy products .(they will go sour) meat

Answer 4

food, drinks, leftovers.