Question

A commercial grade cubical freezer, 3 m on a side, has a composite wall consisting of an exterior sheet of 6.35-mm-thick plain carbon steel, an intermediate layer of 100-mm-thick cork insulation, and an inner sheet of 6.35-mm-thick aluminum alloy (2024). Adhesive interfaces between the insulation and the metallic strips are each characterized by a thermal contact resistance of = 2.5 x 10–4 m3 · K / W. What is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 22°C and −6°C, respectively?

Answer 1

589.5 W

Step-by-step explanation:

Given that

the thickness of the carbon steel and insulation is L(a) = L(c) = 0.00635 m

Width of the freezer, W = 3m

Thermal contact resistance, R(t.c) = 0.00025 m²

T(s.i) = -6°C = 267 K

T(s.o) = 22°C = 295 K

See attachment for calculation