OTEC Historical Background

Abstract

As in other branches of technology, the understanding of the physical and chemical principles underlying the operation of heat engines followed long after such systems were in commercial use. Apparently both the ancient Egyptians and Chinese were able to use steam or combustion gases to do work in special applications; however, the first practical use of a heat engine was the steam-driven piston engine for pumping water from mines, invented in 1698 by the Englishman Thomas Savery. This was followed by a better device invented in 1712 by Newcomen and further developed by Smeaton, which was widely adopted for mining operations in the tin mines of Cornwall and the British coal mines. In 1763, James Watt invented his greatly improved steam engine, which laid the foundation for the industrial revolution based on steam power. Interesting accounts of these developments are presented in Fenn (1982) and Callendar and Andrews (1958). By 1800, there were nearly 500 engines of Watt’s design emplaced throughout England for pumping water, working metal, or other uses. Steam use in ships was successfully demonstrated by Fulton on the Hudson River in New York in 1807. Railroad transportation based on steam-driven locomotives was introduced by Stephenson in 1812 following small beginnings in 1801 by Trevithick. As the steam engines of Newcomen were manufactured and installed, their performance was measured by the amount of water that could be pumped to a given height per bushel of coal burned. The heating value of the coal being used was approximately 1 million Btu per bushel. The data of Table 2–1 show how the thermal efficiency of steam engines improved with time. It is interesting to note that the industrial revolution began with engines of less than 1% efficiency and blossomed with the development of Watt’s engine of 2.7% efficiency. Watt and his predecessors related the performance of their engines in pumping water to what could be accomplished by horses engaged in the same task. An average value of the power capability of a horse was estimated by Watt, who established the unit of one horsepower as the power needed to raise 33,000 pounds 1 foot in 1 minute.