The+Heat+Engine

=Heat Engine=

__Thermal power stations__

To power vaccum cleaners, motor vehicles or industrial machines. We can use prinmary energy sources, such as coal, gas and oil.

A **heat engine** is a device that will take nergy from a hot body and use it to do work. All thermal power stations -- power stations that produce steam to drive turbines -- make use of heat engines.



Coal (1) is crushed in a mill. It is then blown in a stream of air (2) to be burned in a large **boiler** (3) which produces large amounts of steam. The steam turns a **turbine** (4) which turns a **generator** (5). The generator is connected to the **step-up transformer** by very heavy wires which can carry 100 000 A at 25 000 V.

To make the power station more efficient, the steam is cooled in a **condenser** (6). The waste heat is carried to the **cooling tower** (7), where it returns as cool water (8). The clouds you see around cooling towers are not smoke; they are water vapour.

__This is an diagram for the internal combustion engine:__



A gas turbine generator, which is a type of internal combustion engine, is a device that converts energy stored in the fuel to useful mechanical energy in the form of rotational power. The gas turbines will combust natural gas to pro­vide the power necessary to turn the electric genera­tors. Exhaust heat leaving the gas turbine electric generator is used by a heat-recovery boiler to produce steam. Steam generated in the waste-heat boiler then produces more electrical power in a steam turbine generator as it goes to campus for heating and thermal needs.

There arethree important energy flows in a power station. The first is Q1, the nergy taken by heating from the hot source, which heats the boiler. The second is W, the wrok done by the turbine on the generator. The thid is Q2, the energy given by heating from the condenser to cool atmosphere.



All heat engines take nergy from a hot source.Thay can't use all of this to do work, only a part. The rest of the energy they give out by heating to something cold, called a cold sink.