(PET) Power Systems Lesson

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Power Systems Lesson

Introduction

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Power is defined as the rate of work that is done for a load of some sort. In this lesson you will be introduced to electrical power, mechanical power, and fluid power. The technology focus of this lesson will be electrical power.

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Explore

Electrical power is the rate that electrical energy is transferred by an electrical circuit. This can be electricity from the wall to operate your television or battery to start the car. The electrical term for power is Watts (W) and Joule (J) is the unit of electrical energy.

Mechanical power is generated by machines. It is calculated by the work involved and the time to complete the effort. Work is the force exerted on an object multiplied by the distance moved. Thermal work is measured in British Thermal Units (BTU). Horsepower (hp) is the term used to describe power used for mechanical systems. Performance of car engines are rated in horsepower.

Fluid power is a concept that is probably less known but encompasses power of gases and liquids to generate, transmit or manage power. Energy flow of fluids has many variables including density of fluid and temperatures. Fluid power is referenced as fluid pressure, typically pounds per square inch (psi), or fluid flow rate, volume per unit of time. An example would be gallons per minute. Pneumatics is the fluid gas power and hydraulics is fluid liquid power system technologies. Hydraulic systems are most often based upon an oil as the fluid.

 

 

Unfortunately, most of energy that is goes into power generation is lost before it gets to the end user. See the following video, Lost in Transmission, to understand the efficiencies of power generation and how the losses occur.

 

Energy for power generation comes in several forms. See the following presentation to learn about Nuclear Power Plants:

 

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Challenge

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Take Away

Consider the values of fossil fuel or nuclear power plants. Which form of energy conversion is better for society?

Every form of energy has advantages and disadvantages. Consider the information for fossil and nuclear fueled power plants:

Fossil fuel plants

  • source of nearly 40% of US energy related CO2 emissions (source: www.eia.gov, Feb 2018)
  • cause acid rain and mercury emissions that are harmful to water and all living creatures
  • waste product of coal plants, coal ash, contains heavy metals and other cancer causing containments that can end up in groundwater and public water sources

Nuclear power plants

  • low level waste such as protective garments, cleaning supplies, reactive water treatment residues require safe storage until radioactive level is deemed safe
  • high level waste must be permanently stored in specialized containers in secure locations for thousands of years
  • risk of environmental and human tragedy if the power plant fails

 

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