1. Heat Engines and Refrigeration
Presented by
Group 1
(Class B)
November, 2012

2. Outline Heat Engines Type of Heat Engines Carnot Cycle
Petrol and Diesel Engines
Refrigeration
Operating principle
Method of Refrigeration
Recent researches in Heat Engine and Refrigeration

3. Heat Engines
Systems that basically converts heat energy to mechanical energy
Harnessing their work done has been the focus of development

4. Types of Heat Engines Internal Combustion Heat Engine
External Combustion Heat Engine

5. The Carnot Cycle Heat engines cannot convert all the input energy.
The fraction converted is called the thermal efficiency
The maximum possible efficiency of a heat engine is that of a hypothetical (ideal) cycle, called the Carnot Cycle.

6. Petrol and Diesel Engines
η = 1 - 1/(rk-1)
rc = V1/V2
re = V1/V3

7. 4-Stroke Engine
Induction Stroke
Compression Stroke

8. 4-Stroke Engine
Power Stroke
Exhaust Stroke

9. Refrigeration Refrigerator is a reversed heat engine.
Heat is continuously transferred from the cold space to the hotter surroundings.
This is a violation of the natural law of heat transfer hence energy must be put into the system.
Refrigerators are cyclic devices.
The working fluids are called refrigerants.

10. Common Application

11. Operation and Principle

12. Method of Refrigeration
Cyclic Method
Vapour-compression refrigeration
Vapour-absorption refrigeration
Vapour-compression cycle
Ideal vapour compression cycle

13. Method of Refrigeration
Reverse carnot cycle

14. Recent Advancement in Refrigeration Operations
Refrigerant decision based on criteria of safety, costs and environment protection
Refrigerant should have excellent thermodynamic properties, high chemical stability and good physical characteristics.
Substances used as refrigerants are:
Ammonia refrigeration convinces with top energy efficiency
Using carbon dioxide to save energy and money

15. Recent Advancement in Refrigeration Operations
Climate-neutral cooling with hydrocarbons
Water refrigeration with up to 25% potential savings
Air: fast refrigeration at low energy costs
Double advantage for the environment and corporate balance sheets