Heat Transfer between two temperatures

In summary: How often does the door need to be opened during normal working?In summary, I think it would be worth doing an experiment to see how much power is used by opening and closing the door.
  • #1
ShimaParty
2
0
Hi,

I'm trying to calculate energy loss between two areas. One area is -25C and another is +15. The contact area(door) is 20m^2. Is convective heat transfer formula the right way to calculate it, or what should I use? I want to find out the how many kW I need to keep cold area at -25 when the door is open.

Thank you
 
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  • #2
Sounds like a lost cause from your description so far .

If this is a cold room type problem the solution may lie more in redesigning the door system than in calculations and installation of high power cooling equipment .

Anyway not enough information to give proper answers . Please describe the problem in more detail .
 
  • #3
Nidum said:
Sounds like a lost cause from your description so far .

If this is a cold room type problem the solution may lie more in redesigning the door system than in calculations and installation of high power cooling equipment .

Anyway not enough information to give proper answers . Please describe the problem in more detail .

I agree that the solution lies in door system, but the payback on that door system depends on how much do I lose by not doing it.
I appreciate there might be no way how to easily calculate it.

My problem is: I've got a site that is cooled down to -25C. I was told that opening the door(10.2m^2) to the yard(+15C) costs me 500KWh , but I've got no way of verifying that statement. Is there a way how to verify that or not?

Thank you
 
  • #4
It may be possible to come up with an answer experimentally .

You will have a power usage meter supplied by the power company .

Keep the door permanently closed for at least 24 hours - maybe during a holiday period . Measure the power used during this period .

Measure the power used on a normal working day with doors opening and closing for the same period .

See how much difference there is in power usage .

Ideally repeat the experiment a few times .

The above will give reasonable answers if the cold room uses most of the power coming into your site .

You can do a very accurate assesment if you privately install a power usage meter specifically for the cold room .
 
  • #5
What fraction of the time is the door open for during normal working ?
 

1. How does heat transfer occur between two temperatures?

Heat transfer between two temperatures occurs through three main mechanisms: conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between two objects, while convection is the transfer of heat through the movement of fluids. Radiation is the transfer of heat through electromagnetic waves.

2. What factors affect the rate of heat transfer between two temperatures?

The rate of heat transfer between two temperatures is affected by several factors, including the temperature difference between the two objects, the surface area and distance between them, the type of materials involved, and the presence of insulating materials.

3. How can I calculate the amount of heat transferred between two temperatures?

The amount of heat transferred between two temperatures can be calculated using the equation Q = mcΔT, where Q is the heat transferred, m is the mass of the object, c is the specific heat capacity of the material, and ΔT is the change in temperature.

4. What is the difference between heat transfer and heat flow?

Heat transfer refers to the movement of thermal energy from one object to another, while heat flow refers to the amount of thermal energy that is transferred per unit time. Heat flow is also known as heat flux and is measured in watts (W).

5. How does heat transfer between two temperatures affect the surrounding environment?

Heat transfer between two temperatures can affect the surrounding environment in various ways. For example, if the surrounding temperature is lower than the temperature of the object, heat will be transferred from the object to the environment, resulting in a decrease in the object's temperature. This can lead to changes in the physical properties of the object, such as expansion or contraction. Additionally, heat transfer can also impact the temperature and properties of the surrounding air or fluids, causing changes in the overall temperature and conditions of the environment.

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