Heat loss through freezer walls by condiction.xls
KNOWN: Dimensions and thermal conductivity of food/beverage container. Inner and outer surface temperatures.
FIND: Heat flux through container wall and total heat load.
ASSUMPTIONS: 1) Steady State conditions.
2) Negligible heat transfer through bottom wall.
3) Uniform surface temperatures and one-dimensional conduction through remaining walls.
Fundamentals of Heat and Mass Transfer - Frank P. Incropera
To calculate the heat loss through the freezer walls by conduction, considering the dimensions and thermal conductivity of the food/beverage container, inner and outer surface temperatures, and the given assumptions, you can follow these steps:
Determine the surface area of the container: Calculate the surface area of the container by summing the areas of all the walls, excluding the bottom wall.
Calculate the heat flux: The heat flux (q) through the container wall can be calculated using Fourier's Law of heat conduction:
q = (T_inner - T_outer) / (R_total)
Where T_inner and T_outer are the inner and outer surface temperatures, respectively, and R_total is the total thermal resistance of the container wall.
Calculate the total thermal resistance: The total thermal resistance (R_total) of the container wall can be determined by summing the individual thermal resistances of each wall using the formula:
R_total = (L_1 / k_1) + (L_2 / k_2) + (L_3 / k_3) + ...
Where L_i is the thickness of each wall and k_i is the thermal conductivity of each wall material.
Calculate the total heat load: The total heat load (Q) is the product of the heat flux and the surface area of the container:
Q = q * Surface Area
By following these steps, you can determine the heat flux through the container wall and calculate the total heat load for the freezer walls based on the given dimensions, thermal conductivity, inner and outer surface temperatures, and the assumptions of steady-state conditions, negligible heat transfer through the bottom wall, uniform surface temperatures, and one-dimensional conduction through the remaining walls.
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