Thermal engineering
Thermal engineering is a specialized sub-discipline of mechanical engineering that deals with the movement of heat energy and transfer. The energy can be transferred between two mediums or transformed into other forms of energy.

Aspects of thermal engineering
Thermal engineering involves thermodynamics liquid mechanics and heat and mass transfer. This knowledge is important when operating almost any machine. Systems experience heat buildup from mechanical elements and electric circuits. This heat if not redirected can damage the system. Thermal engineers work to design the inclusion of fans or liquid circulators to regulate the internal temperature of the device. Computers and car batteries are two examples of this principle in action.

Thermodynamics
Thermodynamics is the science of energy including production storage transfer and conversion. Thermodynamics which is a branch of both physics and engineering science explains the effects of work heat and energy on a system. To understand thermodynamics it's important to understand the scientific law about energy conservation which states that energy isn't created nor destroyed is can only change its form. Energy does this in thermodynamics through the transfer of heat.

Fluid mechanics
Fluid mechanics concerns liquids gasses and plasmas including how they function and how they react to forces applied to them. This category can be broken down into fluid statics and fluid dynamics. Fluid statics is when fluids are at rest while fluid dynamics deals with fluid flow. Fluid dynamics is an important field of study and is included in most industrial processes especially those involving the transfer of heat.

Heat transfer and mass transfer
Thermal engineers study heat transfer which concerns the creation utilization conversion and exchange of heat between systems. Heat transfer is divided into several mechanisms including:

Heat conduction: Also called diffusion heat conduction is the direct exchange of kinetic energy of particles between two systems when one system is at a different temperature from another or its surroundings.
Heat convection: Heat convection involves the transfer of mass from one area to another. It occurs when the bulk of a fluid transfers heat as matter within the fluid moves.
Thermal radiation: Thermal radiation is heat transfer by electromagnetic radiation without the need for matter to be present between systems. Sunshine is a good example of radiation.

How does thermal engineering work?
Many processing plants use machines that utilize heat transfer. The thermal engineer is responsible for ensuring the right amount of energy is transferred for the machine's operation. Too much energy and the components could overheat and fail. Too little energy and the whole machine could shut down.

Some systems that use heat transfer and may require a thermal engineer include:

Combustion engines
Compressed air systems
Cooling systems including for computer chips
Heat exchangers
HVAC
Process-fired heaters
Refrigeration systems
Solar heating
Thermal insulation
Thermal power plants

What does a thermal engineer do?
Thermal engineers use their background in thermodynamics to create maintain or repair mechanical systems. The systems usually involve a process that transfers heat energy into or out of other forms of energy. The heat is typically transferred through fluids such as liquids or gasses so a strong knowledge of fluid dynamics is important.&

They also work on systems of various scales from extremely large such as an airplane engine or industrial heater to very small such as within electronics. Sometimes thermal engineers work on theoretical projects rather than actually building or repairing completed systems. Activities and responsibilities may include: