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Last time we calculated the potential energy hidden within a coffee mug resting on a shelf. The concept of a passive object possessing energy may not be something all readers can identify with, but the secret behind that mug’s latent energy lies within The Law of Conservation of Energy, the topic we’ll be discussing today. Julius Robert von Mayer, a German physicist of the mid 19th Century, is the man behind the Law. He posited that energy cannot be created or destroyed, it can only be transferred from one object to another or converted from one form of energy to another. Forms of energy include potential, kinetic, heat, chemical, mechanical, and electrical, all of which have the ability to become another form of energy. Let’s take our coffee mug for example. Where did its potential energy come from? Ultimately, from the radiant energy emitted by the sun. The sun’s radiant energy was absorbed by plants and then converted to chemical energy through the process of photosynthesis, enabling them to grow. When they were later eaten by humans and other animals, the plants’ chemical energy became incorporated into their bodies’ cells, including the arm muscles used to lift the mug to the shelf. In the act of lifting the cup, the arm’s muscle cells converted their own chemical energy into mechanical energy. And because lifting a mug to a shelf is work, for some of us greater than others, some of the arm’s chemical energy became heat energy which was lost to the environment. Because of the elevated perch provided to the mug by the arm, which was in direct defiance of Earth’s gravitational pull, the arm muscles’ mechanical energy was transferred to the mug and converted to latent potential energy, because without that shelf to support it, the mug would fall to the ground. The mug’s potential energy would realize its full potential if it should be sent crashing to the floor, at which time it would become another form of energy. The mischievous orange kitty seems to have just that in mind.
We’ll talk more about the mug’s potential energy being converted to other forms next time. Copyright 2015 – Philip J. O’Keefe, PE Engineering Expert Witness Blog ____________________________________
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Posts Tagged ‘chemical energy’
The Law of Conservation of Energy
Wednesday, September 2nd, 2015
Coal Power Plant Fundamentals
Sunday, January 23rd, 2011| Several years ago I was asked by power producers within the electric utility industry to write and then present a training course on the subject of coal power plant fundamentals. The finished product was a two day introductory course on the energy transformation process within a coal fired plant.
Since that time my seminar, entitled Coal Power Plant Fundamentals, has been presented to a variety of audiences, including Mirant Corporation, Platte River Power Authority, and Integrys Energy Group, Inc. Audience makeup has been diverse and has included equipment manufacturers, mining companies, power industry consultants, and regulatory agencies. This seminar, which I continue to present today in meeting rooms across the country, covers all major systems in a typical power plant, from coal handling when the coal first enters the plant, to its eventual end destination, the electrical switch yard which facilitates power transmission to customers. My Power Point presentation is embellished with ample illustrations, including photographs that I have taken during the course of my career and diagrams which I created using CAD, or Computer Aided Drawing software, one of which is featured below. In addition to the overhead slides, I provide a 150-page bound book which is distributed to seminar attendees. They use it to both follow along with my lecture and have a source of refresher material to take home with them. I’ve been told that having my illustrations in front of them makes a world of difference towards their understanding of the subject matter. The unique thing about my course is that it focuses on the simplified presentation of complex engineering concepts, much like my blogs do. Of course it always helps to have an engineering background or scientific background of sorts, but I wrote the course to accommodate understanding of the subject matter by individuals without any technical background. Accountants, salespersons, administrative staff, plant operating and maintenance workers, and journalists have all found the course to be easy to follow, interesting, and informative. So how do you get electricity from coal? To answer this question and give you a sampling of my seminar material let’s take a look at Figure 1.
Figure 1 – The Coal Power Plant Energy Transformation Process Following along from left to right, the coal is first burned in order to transform the chemical energy which it contains into heat energy. That heat energy is then absorbed by water inside a nearby boiler, where it is converted into steam. The heat energy in the steam flows through a pipe into a steam turbine where it is again transformed, this time into mechanical energy that enables the turbine shaft to spin. The mechanical energy in the turbine is then transmitted by its shaft, enabling it to turn an electrical generator. And, finally, the mechanical energy is transformed by the generator into electrical energy for our usage. Simple process, right? Well, maybe, maybe not. My illustration certainly helped to simplify things, but there are a lot of details that were purposely omitted so as not to “muddy the waters.” It’s those details which have the potential to make things a lot more complicated, and next week we’ll begin to take a closer look at some of them. _____________________________________________
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