Which of the following would lead to a reduction in thermal resistance?
Thermal resistance is a heat property and a measurement of a temperature difference by which an object or material resists a heat flow.
In conduction thermal resistance is given as
Q = Δx/kA
Where
Δx = distance between two-point
A = Cross-section area
K = Thermal Conductivity
⇒ A greater thickness means less heat flow and so does a lower conductivity. Together these parameters form the thermal resistance of the construction. The thermal resistance is proportional to the thickness of a layer of the construction and inversely proportional to its conductivity. Thus reduction in thickness and an increase in the area results in a reduction of thermal resistance.
⇒ Convective stirring develops when heating up fluid from below. The heating decreases the fluid’s density near the bottom and produces fluid being less dense than the surrounding fluid. Stirring of fluid and cleaning the heating surface increases the h value (convective heat transfer), and thus reduces thermal resistance.
⇒ In radiation, heat flow increases with an increase in temperature and reduces with the reduction in emissivity. Thus thermal resistance reduces.