Heat Engine
It is a cyclically operating device which absorbs energy
as heat from a high temperature reservoir, converts part of the energy into
work and rejects the rest of the energy as heat to a thermal reservoir at low
temperature.
Schematic Diagram of Thermal Power Plant
Schematic Diagram of Thermal Power Plant |
The working fluid is a substance, which absorbs
energy as heat from a source, and rejects energy as heat to a sink.
Q2 –
Heat rejected to cooling water in condenser
WP –
Work done on the pump
Wnet=WT-WP
W = Q1 – Q2
Thermal
Efficiency,
Schematic Diagram of Heat Engine
Schematic Diagram of Heat Engine |
Schematic Diagram of Refrigerator and Heat Pump
Schematic Diagram of Refrigerator(a) and Heat Pump (b) |
QL –
Heat absorbed from low temperature thermal reservoir
QH –
Heat rejected to a high temperature thermal reservoir when work (W) is done on
it.
In a reversible, isothermal expansion of an ideal gas,
all the energy absorbed as heat by the system is converted completely into
work. However this cannot produce work continuously (not a cycle).
A thermal store is a vessel for storing and managing heat until it is needed. It differs from a conventional hot water cylinder as the stored water is not fed to the taps directly from the thermal store. Thermal stores can provide space heating and mains pressure hot water or hot water only. MyJobQuote