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An example of thermal technology includes climate control systems, like the rooftop air conditioning units seen here.
Image credit: Wayne Calabrese/Photonica Collection/Getty ImagesAs gas prices rise, we start to pay more attention to emerging energy technologies. Currently, one of the most promising is thermal technology, which harnesses heat – one of the most abundant forms of energy.
To grasp how thermal technology works, it's essential to understand thermodynamics – the science that studies how heat moves. Although it might sound complicated, we already know its basic principles. For example, when we place a hot cup of coffee in a freezer, the coffee cools down quickly. This happens because heat naturally flows from hotter objects to cooler ones. The heat from the coffee moves into the cold air, continuing until both the coffee and air reach the same temperature.
The term 'thermal technology' can be confusing, as it's used in various contexts. Generally, it refers to ways we use heat to achieve specific outcomes. For example, people often associate thermal technology with climate control, such as preventing heat from escaping with insulation or adjusting the temperature of a room. Since heat always moves from hot to cold, reversing this process is a challenge. While it’s impossible according to thermodynamics, air conditioners use special fluids that follow these laws to lower room temperatures. Check out 'How Air Conditioners Work' to discover how they accomplish this.
Certain electronics, like thermal fax machines, are also said to utilize thermal technology. These devices use heat for their functions, unlike climate control systems that move heat around. For instance, a thermal fax machine creates heat from electricity within its print head, then applies this heat to special thermal paper or through a transfer ribbon to print faxes. This technique results in a simple, reliable fax machine that doesn't require ink cartridges to operate.
While converting heat into usable energy is challenging, recent developments in thermal technology have made it more achievable than ever. One of the most promising applications involves harnessing the sun's heat to generate electricity. Next, we'll explore how this process works and why some consider it the energy of the future.
Hot Topic: Solar Thermal Power Technology
A solar tower surrounded by heliostats
Image credit: Kim Steele/Photodisc/Getty ImagesScientists have long known that the sun's rays carry vast amounts of energy to Earth in the forms of light and heat. However, capturing and converting this energy into usable electricity has proven difficult. For example, photovoltaic (PV) panels can convert sunlight into electricity to power homes or buildings, but they remain relatively expensive and inefficient.
Some people believe that solar thermal technology represents the ultimate solution for affordable, clean, renewable energy. While fossil fuels may contribute to global climate change and are becoming increasingly costly, solar thermal energy remains clean and could soon be competitively priced. By converting the sun’s heat into usable electricity, this technology has the potential to help reduce reliance on fossil fuels.
Unlike photovoltaic (PV) panels, which directly convert solar energy into electricity, solar thermal power works indirectly by using heat to turn water into steam. This steam, similar to what is used in fossil-fueled power plants, drives a turbine that powers an electric generator.
There are several types of systems designed to capture solar heat:
- Solar tower: Surrounded by heliostats (special mirrors that track the sun), a solar tower collects the sun's energy. The heat is captured and stored in special liquid salts, which are then transported from the tower to a steam generator.
- Parabolic troughs: These systems use the parabolic shape to intensify and collect heat from the sun at any time of day. Tubes filled with a special fluid run through the system, absorbing the heat as they pass by. The fluid then transfers the heat to water, turning it into steam. The fluid used is an oil that can withstand temperatures up to 750 degrees Fahrenheit (400 degrees Celsius) [source: Biello]. Molten salts are used to store excess heat for use when the sun is not shining.
- Fresnal reflector: Rather than heating fluid, this system heats water directly by increasing atmospheric pressure. The resulting steam can then be used to power a turbine.
Parabolic troughs gather heat for a solar power plant in the Mojave Desert, California.
Image credit: Kathleen Campbell/Stone Collection/Getty Images- Solar dish: These dishes track the sun to capture heat throughout the day. Mirrors focus sunlight onto a single point, converting the heat into mechanical energy by heating a compressed fluid. Expanding this fluid powers a piston, generating useful energy.
The Mojave Desert in California hosts power plants that utilize both parabolic troughs and solar towers. Several countries, including Spain, Morocco, and Israel, are either building or planning to build solar thermal power plants as well [source: Wald].
How can countries with limited sunshine benefit from plants like these? Some believe it's entirely possible to set up a network of high-voltage direct current transmission lines to transport electricity over long distances. This way, sun-rich nations can build solar thermal power plants and transmit the energy to regions with less sunlight.
As the technology progresses, many believe it will soon be affordable enough to rival fossil fuels, particularly with the support of high carbon emission taxes. This could become feasible if the cost of solar thermal power drops to around 10 cents per kilowatt-hour [source: Biello].
Visit the next page for additional resources to expand your knowledge on renewable energy.
