Why does the cold air fall out of the freezer when it's opened?

In summary, the conversation discusses the concept of opening a freezer and letting out cold air. According to thermodynamics, heat moves from hot to cold, so when the freezer is left open, warm air from the room replaces the cold air, causing the freezer to use more energy to cool down again. This can also lead to a rise in temperature in the room. Additionally, the conversation addresses the idea of using the freezer to cool the room, which is not an effective method.
  • #1
bjon-07
84
0
This may be a stupid, but here it goes,

When ever i stand in front of the freezer i always get yelled at for letting the cold air of of the freezer.

But according to thermodynamics (the 1st law a beileve) heat moves from hot to cold. So when i leave the freezer open am i letting IN HEAT, reather than letting out the colder air that is inside the freezer.

I also relazie that the deinsity of a gas is proprational to it temperature, so mabye the cold air falls out of the freezer.

Can someone please tell me what is happening when i open the freezer, i have taken G-Chem in college so i know the basics of thermo,

i
 
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  • #2
You've got it right. The cold air rolls out of the freezer and falls toward the floor. It is replaced by warm air already present in the room.

The freezer then has to expend energy removing the heat from the warm air now present in the freezer cavity.

- Warren
 
  • #3
I am not sure that there is any difference between "letting in heat" or "letting out cold". The net effect is that the temperature inside the freezer increases, this must be accompanied by running the compressor to cool it back down, this work done increases the room temperature MORE then the decrease due to the "escaping cold" of the freezer. In the long run by keeping the freezer door open you heat up the room.
 
  • #4
Just to avoid confusion, maybe we should specify what type of transfer we are talking about: Convective, radiative, or conductive. Convection carries the cool air out of the fridge. Convection also allows the cool, escaped air to warm. Conduction allows heat to leak in through the walls into the fridge, Radiation wouldn't apply much here.
 
  • #5
It's not the cold air per se that is the problem since its heat capacity is usually negligible compared with that of the contents of the freezer and its walls. The problem is when the contents are heated by the warm air entering the freezer and it costs energy ($$$) to remove the heat.
 
  • #6
Thats a very common question: Can we use the freezer to cool the kitchen? And the answer is obviously NO...
 
  • #7
chroot said:
You've got it right. The cold air rolls out of the freezer and falls toward the floor. It is replaced by warm air already present in the room.
- Warren


HOWEVER! It would be really, really dumb to point this out to your parents the next time they tell you not to let the "cold" out!
 

Related to Why does the cold air fall out of the freezer when it's opened?

1. What is thermodynamics in the kitchen?

Thermodynamics in the kitchen refers to the study of the transfer of heat energy in cooking and food preparation. It involves understanding how heat is transferred, how it affects the cooking process, and how it affects the final outcome of a dish.

2. How does temperature affect cooking?

Temperature plays a crucial role in cooking as it determines the rate of heat transfer and the chemical reactions that occur during cooking. Different foods require different temperatures for optimal cooking, and understanding this is essential for achieving desired results.

3. How does thermodynamics affect food preservation?

Thermodynamics plays a significant role in food preservation by controlling the growth of microorganisms and chemical reactions that cause spoilage. By maintaining specific temperatures during food storage, we can slow down or prevent the spoilage process and prolong the shelf life of food.

4. What are the different methods of heat transfer in cooking?

The three main methods of heat transfer in cooking are conduction, convection, and radiation. Conduction is the transfer of heat from a heat source to the food through direct contact. Convection is the transfer of heat through a liquid or gas medium, such as boiling water. Radiation is the transfer of heat through electromagnetic waves, such as in a microwave.

5. How can I apply thermodynamics in my cooking?

You can apply thermodynamics in your cooking by understanding the principles of heat transfer and using them to your advantage. For example, you can use convection to evenly cook food in an oven by placing it on a baking sheet. You can also use insulation techniques to retain heat and keep food warm. Understanding how heat affects different ingredients can also help you adjust cooking times and temperatures for the best results.

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