Question

Texts: A chiller box is made from polyethylene (k=0.028 W/m·K) and has an inner dimension of 2 m x 2 m x 2 m. The inner box temperature is to be maintained at 0°C and the surface temperature must not be above 20°C. The ambient temperature is 25°C. There is no heat transfer from the bottom of the box and the surrounding temperature is the same as the ambient temperature. (i) Find the thickness of the box material that would maintain a conduction heat dissipation of 500 W. (ii) What is the heat loss due to radiation if hr = 3 W/m²·K? (iii) What is the total heat loss to the environment if the convection heat transfer to the air is characterized by a free convection coefficient of h = 2 W/m²·K?

          Texts: A chiller box is made from polyethylene (k=0.028 W/m·K) and has an inner dimension of 2 m x 2 m x 2 m. The inner box temperature is to be maintained at 0°C and the surface temperature must not be above 20°C. The ambient temperature is 25°C. There is no heat transfer from the bottom of the box and the surrounding temperature is the same as the ambient temperature.

(i) Find the thickness of the box material that would maintain a conduction heat dissipation of 500 W.
(ii) What is the heat loss due to radiation if hr = 3 W/m²·K?
(iii) What is the total heat loss to the environment if the convection heat transfer to the air is characterized by a free convection coefficient of h = 2 W/m²·K?

Added by Shannon S.

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