Heat Loss Calculator :
Enter the values of thermal transmittance, U(W/m2.K), surface area, A(m2) and temperature difference, T(°C) to determine the value of Rate of Heat Loss, q(W).
Heat Loss Formula:
Heat loss refers to the transfer of thermal energy from a warmer space to a cooler one, typically through walls, roofs, windows, or other barriers. This process occurs due to the temperature difference between the inside and outside environments, driving heat to move from the warmer side to the cooler side. Heat loss is crucial in fields like building construction, HVAC design, and industrial processes, as it affects energy efficiency, heating requirements, and overall environmental control.
The rate of heat loss is influenced by various factors, including the thermal conductivity of materials, surface area, insulation quality, and the temperature difference across the barrier. The thermal transmittance, or U-value, measures how well a material allows heat to pass through it; lower U-values signify better insulation and less heat transfer. The product of the U-value and the surface area represents the overall thermal transmission capacity for a given area, enabling the calculation of heat loss.
The formula for heat loss uses the U-value (U), area of the surface (A), and temperature difference (ΔT) between the two environments. This formula calculates either the total heat loss (Q) over a period or the rate of heat loss (q) at a specific moment, depending on the units used for the inputs. By controlling or reducing heat loss, energy usage can be optimized, leading to better thermal management and reduced heating costs.
The Rate of Heat Loss, q(W) in Watts is equal to the product of the thermal transmittance, U(W/m2.K) in Watts per square metres Kelvin, the surface area, A(m2) in square metres and the temperature difference, T(°C) in degree Celsius between the interior and exterior environments.
Rate of Heat Loss, q(W) = U(W/m2.K) * A(m2) * T(°C)
q(W) = rate of heat loss in Watts, W.
U(W/m2.K) = thermal transmittance in Watts per square metres Kelvin, W/m2.K.
A(m2) = surface area in square metres, m2.
T(°C) = temperature difference in degree Celsius, °C.
Heat Loss Calculation:
1.An uninsulated wall has a surface area of 50 m2, a U-value of 0.3 W/m2.K and the temperature difference between the interior and exterior is 25°C. Calculate the rate of heat loss through the wall.
Given: U(W/m2.K) = 0.3 W/m2.K, A(m2) = 50 m2, T(°C) = 25°C.
Rate of Heat Loss, q(W) = U(W/m2.K) * A(m2) * T(°C)
q(W) =0.3 * 50 * 25
q(W) = 375W.
2.A window with an area of 2 m2 has a U-value of 1.1 W/m2.K. If the rate of heat loss (q) through the window is measured to be 220 W, find the temperature difference (ΔT) across the window.
Given: U(W/m2.K) = 1.1 W/m2.K, A(m2) = 2 m2, q(W) = 220W.
Rate of Heat Loss, q(W) = U(W/m2.K) * A(m2) * T(°C)
T(°C) = q(W) / U(W/m2.K) * A(m2)
T(°C) = 220 / 1.1 * 2
T(°C) = 100°C.