Heat Transfer Calculator

Heat transfer is the thermal energy transition from a system at a higher temperature to one at a lower temperature. This calculator utilizes four fundamental physical equations depending on the mechanism:

1. Basic Heat (Specific Heat): Q = c * m * deltaT / 1000, where c is specific heat capacity, m is mass, and deltaT is the temperature change.

2. Conduction (Fourier's Law): Q = k * A * (deltaT / d) * t, where k is thermal conductivity, A is area, d is thickness, and t is time.

3. Convection (Newton's Law of Cooling): Q = h * A * deltaT, where h is the convective heat transfer coefficient.

4. Radiation (Stefan-Boltzmann Law): Q = sigma * epsilon * A * (T2^4 - T1^4), where sigma is the Stefan-Boltzmann constant (5.670367 * 10^-8) and epsilon is emissivity.

Let us calculate the conductive heat transfer through a flat building wall over a period of 3,600 seconds (1 hour). Assume the following values:

• Thermal conductivity (k): 0.8 W/(m·K)
• Surface Area (A): 15 square meters
• Inside Temperature (T2): 295 K
• Outside Temperature (T1): 275 K
• Wall Thickness (d): 0.2 meters
• Time (t): 3,600 seconds

First, find the temperature difference: 295 - 275 = 20 K. Next, divide by the thickness: 20 / 0.2 = 100 K/m. Multiply by conductivity and area: 0.8 * 15 * 100 = 1,200 Watts (Joules per second). Finally, multiply by the time of 3,600 seconds: 1,200 * 3,600 = 4,320,000 Joules (or 4.32 MJ) of total heat transferred.

• Consistent Units: Always ensure your temperature inputs are in Kelvin or Celsius consistently, and distances are converted to meters before calculating.
• Material Properties: Thermal conductivity and specific heat values change with temperature; use values appropriate for your specific operating range.
• Emissivity Limits: Emissivity is a dimensionless value strictly between 0 and 1, representing how efficiently a surface radiates energy compared to an ideal blackbody.