Applied thermal engineering 1

Applied Thermal Engineering - I

UNIT – V (Part – A)

Refrigeration

,Contents:
Fundamentals
• Introduction
• Fundamentals of refrigeration – COP & TR

Air- • Reversed Carnot cycle
Refrigeration
system • Air refrigeration systems – Open type and Closed type
• Bell-Coleman cycle (Reversed Brayton cycle)
• VCR system – (T-s & p-h diagrams)
VCRs & VARs
• Factors affecting VCRs
• VARS
Refrigerants
• Refrigerants and its properties

,Refrigeration :
Refrigeration is the science of producing and maintaining
temperatures below that of the surrounding atmosphere.
Refrigeration system:
The equipment employed to maintain the system at a low
temperature is termed as refrigerating system and the system which
is kept at lower temperature is called refrigerated system..

Refrigerant:
A ‘refrigerant’ is defined as any substance that absorbs heat through
expansion or vaporisation and loses it through condensation in a
refrigeration system. Ex: Air, NH3, R11, R22, R134, etc.

, Applications of Refrigeration:
1. Ice making
2. Transportation of foods above and below freezing
3. Industrial air-conditioning
4. Comfort air-conditioning
5. Chemical and related industries
6. Medical and surgical aids
7. Processing food products and beverages
8. Oil refining and synthetic rubber manufacturing
9. Manufacturing and treatment of metals
10. Freezing food products
11. Miscellaneous applications :
(i) Extremely low temperatures
(ii) Plumbing
(iii) Building construction, etc.