A refrigerated warehouse stores perishable goods at a constant indoor temperature of −5∘C while the outdoor temperature typically hovers near 30∘C. The outer walls consist of a single, uniform layer of insulation. An engineer proposes to double the thickness of this insulation layer in order to reduce the warehouse’s energy consumption.
Respond to the following prompts about this proposal.
(a) Describe qualitatively how the rate of thermal energy conducted through the wall depends on the insulation’s thickness when all other parameters remain unchanged.
(b) Explain why selecting a material with a lower thermal conductivity might achieve the same reduction in heat transfer as doubling the thickness, and discuss one practical factor (other than thermal performance) that could influence the choice between the two strategies.