Calculating Heat Transfer in a Brick Wall: Homework Question Explained

Use * for multiplication.In summary, the problem involves calculating the rate of heat transfer through a brick wall with given dimensions and thermal conductivity. Using the formula Q* = (T1-T2)*(k)*(A)/^X, where T1 and T2 are the temperatures of the inner and outer surfaces, k is the thermal conductivity, A is the surface area, and ^X represents the thickness of the material, the average rate of heat transfer was found by filling in the values and multiplying by 3600 seconds to convert to joules per hour.
  • #1
bmcgann
3
0

Homework Statement



Consider a brick wall, 4.0 m high, 6.0 m wide and 300
mm thick, where the thermal conductivity of the brick
is 0.8 W.m-1.K-1. During a particular one-hour period,
the temperatures of the inner and outer surfaces were
measured to be T1 14oC and T2 6oC respectively. The average
rate of heat transfer

Q*=Rate of heat tranfer (i think)

Homework Equations



The equation that I am trying to use is Q* = (T1-T2)*(k)*(A)/^X not sure if correct.

The Attempt at a Solution



^X is just the thickness of material
A is 4*6=24m^2
k = 0.8W/mK

so i filled in and the divided by 3600s to get an answer in joules, i know i have can wrong can someone help me out with what formulae to use for this question?
 
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  • #2
You are using the correct formula. A watt is 1 joule/second so you should not divide by 3600. To get joules/hr, multiply by 3600.
 
Last edited:
  • #3
Careful with the use of ^. It means exponentiation to most people.
 

1. What is heat transfer?

Heat transfer is the process by which thermal energy is transferred from one object or system to another. It can occur through three main mechanisms: conduction, convection, and radiation.

2. How does heat transfer occur?

Heat transfer occurs when there is a temperature difference between two objects or systems. In order to reach thermal equilibrium, the heat energy will flow from the hotter object to the colder one until their temperatures are equal.

3. What is the difference between conduction, convection, and radiation?

Conduction is the transfer of heat through direct contact between objects or particles. Convection is the transfer of heat through the movement of a fluid, such as air or water. Radiation is the transfer of heat through electromagnetic waves, such as from the sun.

4. What factors affect heat transfer?

The rate of heat transfer depends on several factors, including the temperature difference between objects, the thermal conductivity of the material, the surface area and distance of the objects, and the presence of insulating materials.

5. Why is heat transfer important?

Heat transfer is important in many scientific and engineering applications, such as in thermodynamics, materials processing, and climate control. It also plays a crucial role in our daily lives, from cooking food to regulating our body temperatures.

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