5 Examples of Thermal Energy Transfer Explained

Examples of thermal energy transfer are; solar heating, geothermal energy in fluids, space heating, ocean heat circulation, and steam generation.

This article discusses the examples of thermal energy transfer, as follows;

1). Solar Heating (as one of the Examples of Thermal Energy Transfer)

Solar thermal heating is the transfer of solar energy from the Sun, to other media or bodies, in the form of radiant heat.

The concept of solar thermal heating is very important as a means to understand some of the primary mechanisms of energy supply, storage and transfer, in the Earth's ecosystem. It also highlights the nature of solar thermal energy, which is heat produced from nuclear fusion reactions occurring spontaneously in the Sun.

Solar energy is transferred as heat through radiation, which transmits the heat across a vacuum to any material without need for an intermediate thermal conductor.

One of the manmade systems that effectively depicts the use of solar heating is a solar heater.

The method of transfer of heat used in solar heaters is radiation; whereby a reflective surface called a 'solar collector' is used to reflect incident radiant heat to a target medium, which is often water [5].

After solar thermal heat has been captured using a solar collector, it may then be applied to any of various purposes like electricity generation, space heating and industrial processing [4].

It must be noted that after this radiant form of heat from the Sun has been captured, subsequent transfer of the heat can be achieved through conduction or convection, using heat exchangers (or heat transfer media; HTM).

2). Geothermal Energy in Fluids

The types of heat transfer in geothermal energy systems are; conduction and convection.

Geothermal fluids are gases and liquids in the subsurface that absorb geothermal heat from the Earth's core by conduction, and transmit or circulate this heat by convection.

The main geothermal fluids are water, water vapor and air.

The fluid convection process in geothermal systems is a density-driven process whereby hot fluid rises and is replaced by descending, cold fluid in a continuous loop.

Convection is what enables geothermal energy to be transferred from one point in a geothermal fluid, to another. A similar mechanism is used in geothermal power plants and other geothermal energy systems, to ensure that heat is in continuous circulation [7].

3). Space Heating (as one of the Examples of Thermal Energy Transfer)

Thermal energy is transferred through space by the mechanism of radiation, so that the heat is transmitted in electromagnetic form through a vacuum, without needing to flow through any material from one point to another.

A space heater that is warming a room transmits heat into the room through radiation, since there is no material medium used to transfer thermal energy from the heater through space. However, after heat has been transmitted into the room, it may be circulated within the room by convection, so that air masses are continuously circulated based on differences in temperature and density.

The sequential combination of radiation and convection helps to transmit and distribute heat during space heating operations.

Heat energy losses from the room may occur by conduction or convection, if there is no effective means of insulation in place to conserve energy.

4). Ocean Heat Circulation

The type of heat transfer in the ocean is convection, whereby fluids circulate continuously due to differences in density that are induced by differential heating [2].

Thermal energy is transferred in the ocean when hot or warm water rises due to low density, while cold water descends or moves downward due to relatively-high density.

Ocean thermal energy transfer also affects the atmosphere significantly, so that heat is continually exchanged between oceans and atmospheric gases [6]. This plays a major role in the speed, direction and distribution of wind, as well as in regional weather and climatic conditions.

5). Steam Generation (as one of the Examples of Thermal Energy Transfer)

The process of steam generation comprises of heat production, heat absorption and phase change.

Heat transfer can be used to generate steam when an energy resource like fossil fuel or biomass is made to undergo combustion and release large amounts of heat that are absorbed by water through conduction, thereby causing boiling and vaporization.

The type of energy transfer in steam generation is a combination of conduction and convection.

Aside fuel, solar thermal heating can also be used to generate steam with solar collectors and concentrators [3] [1].

Conclusion

Examples of thermal energy transfer are;

1. Solar Heating

2. Geothermal Energy in Fluids

3. Space Heating

4. Ocean Heat Circulation

5. Steam Generation

References

1). Adinberg, R.; Zvegilsky, D.; Epstein, M. (2010). "Heat transfer efficient thermal energy storage for steam generation." Energy Conversion and Management 51(1):9-15. Available at: https://doi.org/10.1016/j.enconman.2009.08.006. (Accessed 8 February 2023).

2). Faizal, M.; Ahmed, M. R. (2011). "On the ocean heat budget and ocean thermal energy conversion." International Journal of Energy Research 35(13):1119 - 1144. Available at: https://doi.org/10.1002/er.1885. (Accessed 8 February 2023).

3). Ghasemi, H.; Ni, G.; Marconnet, A. M.; Loomis, J.; Yerci, S.; Miljkovic, N.; Chen, G. (2014). "Solar steam generation by heat localization." Nat Commun. 2014 Jul 21;5:4449. Available at: https://doi.org/10.1038/ncomms5449. (Accessed 8 February 2023).

4). Philibert, C. (2005). "The present and future use of solar thermal energy as a primary source of energy." Available at: https://www.researchgate.net/publication/239585947_The_present_and_future_use_of_solar_thermal_energy_as_a_primary_source_of_energy. (Accessed 8 February 2023).

5). Sarbu, I.; Adam, M. (2011). "Applications of solar energy for domestic hot-water and buildings heating/cooling." Available at: https://www.researchgate.net/publication/259867235_Applications_of_solar_energy_for_domestic_hot-water_and_buildings_heatingcooling. (Accessed 8 February 2023).

6). Seidov, D. (2009). "Heat Transport, Oceanic and Atmospheric." Encyclopedia of Paleoclimatology and Ancient Paleoenvironment (pp.407-409), Springer. Available at: https://doi.org/10.1007/978-1-4020-4411-3_102. (Accessed 8 February 2023).

7). Wu, W-T.; Aubry, N.; Antaki, J.; McKoy, M.; Massoudi, M. (2017). "Heat Transfer in a Drilling Fluid with Geothermal Applications." Energies 10(9):1349. Available at: https://doi.org/10.3390/en10091349. (Accessed 8 February 2023).