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Heat Engines and Refrigeration

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Presentation on theme: "Heat Engines and Refrigeration"— Presentation transcript:

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


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