Engines, Heat Pumps and Refrigerators Theory Flashcards
What is a heat engine?
Any device that uses heat to perform work
What are the three essential features for a heat engine?
1 - Heat is supplied to the engine from a hot reservoir
2 - Part of the input heat is converted to work by the working substance
3 - The remainder of the heat is rejected to a cold reservoir
What makes an efficient heat engine?
A large amount of work produced from as little input heat as possible
What is a reversible process?
A process where both system and surroundings can be returned to their exact initial states
What are the requirements for a reversible process?
no energy dissipation
What is a Carnot Engine?
An idealised model for a reversible engine
What type are the thermal processes for a Carnot Engine?
All thermal processes are either isothermal or adiabatic
What is a refrigerator/air conditioner/heat pump?
A heat engine operating in reverse
Make heat flow from hot to cold
How does the reverse heat engine work?
Work is done to remove heat from the cold reservoir and deposit it into the hot reservoir
