Technologies that harness heat power
Heat power can be converted into electricity or used directly as heating. There are several technologies we use to utilize heat power, depending on the temperature of the heat. Here’s a quick overview of the main three.
The Rankine Cycle
The Rankine Cycle converts hot water into energy. Here’s how: the steam from hot water is pressurized and pushed through a turbine. The turbine in turn is connected to a generator that creates electricity. Because this takes place in a closed loop system, once the steam is condensed by the generator and returns to water, it can be used again. The cycle then repeats itself.
In what is called an Organic Ranking Cycle, water is replaced with what’s called a working fluid. This enables energy to be generated either from sources with lower temperatures, though this usually leads to a loss in efficiency. The fluid could also have a higher boiling point than water, which would have the reverse effect and increase the efficiency.
Note: Steam turbines are used to generate electricity in coal and nuclear power plants. However, coal requires combustion, which generates CO2. The downside of nuclear power plants is primarily the problem of nuclear waste.
The Stirling engine
Dating back to the 19th century, the Stirling engine is a relatively simple technology that derives its power from the difference between hot and cold temperatures. Watch this a super straightforward explanation of how it works. This elegant machine is used in a handful of combined heat and power applications.
Heat pumps have great potential for reducing the CO2 impact of heating our homes. A heat pump is a device that uses a small amount of energy to move heat from one location to another. Heat pumps are typically used to pull heat out of the air or ground to heat a home, office building, or even whole neighborhoods (called district heating). They can also be reversed and be used for cooling.