2. CONTENTS
• Introduction
• Simple Vapour Absorption System
• Practical Vapour Absorption System
• C.O.P of Ideal Vapour Absorption System
• Properties of Ideal Refrigerant and Absorbent
• Properties of Ideal Refrigerant-Absorbent combination
• Advantages of Absorption system over Compression system
• Domestic Electrolux Refrigerator
• Principle & Working of Domestic Electrolux refrigerator
• Advantages & Disadvantages of Domestic Electrolux Refrigerator
• References
3. INTRODUCTION
• It is a heat operated system.
• It is quite similar to Vapour Compression systems. Condensation and
evaporation takes place at two different pressure levels to achieve refrigeration.
• The main motive is to raise the temperature of the refrigerant from evaporator
pressure to condenser pressure.
• Here refrigerant is dissolved in inert liquid in absorber and pumped to
condenser.
• After raising pressure of refrigerant it is separated from solution by heating.
• After condensation in condenser, refrigerant is throttled by expansion valve and
then it evaporates in evaporator providing the refrigeration effect.
4. SIMPLE VAPOUR ABSORPTION SYSTEM
• Ammonia vapour from evaporator is
absorbed by water in absorber.
Condensation heat released is absorbed by
cooling water.
• After being pumped to generator, heat is
supplied which gives ammonia vapour.
Weak sol. sent back to absorber.
• High pressure vapour is condensed to high
pressure liquid ammonia in condenser.
• Liquid ammonia is throttled by expansion
valve, and then it evaporates absorbing heat
from evaporator.
Simple Vapour Absorption System
9. PROPERTIES OF IDEAL REFRIGERANT
& ABSORBENT
Properties of ideal refrigerant :
• It should boil b/w 2˚-10 ˚C and condense at 40
˚C or above. (pressure around atmospheric)
• Large latent heat of vaporization.
• High critical temperature.
• Low specific heat.
• Stability in complete cycle.
Properties of ideal absorbent :
• Greater affinity for refrigerant.
• Heat released during absorption of refrigerant
should be minimum.
• High boiling point.
• Low specific heat.
• Chemical stability.
10. PROPERTIES OF IDEAL REFRIGERANT-
ABSORBENT COMBINATION
• Refrigerant should have high affinity for absorber at low temperatures & less affinity
at high temperatures.
• Mixture should have low specific heat and viscosity.
• It should be non-corrosive.
• Large difference in normal boiling points of refrigerant and absorbent.
Commonly used combinations in air-
conditioning applications :
• Ammonia-water
• Lithium-bromide water
11. ADVANTAGES OF ABSORPTION SYSTEM
OVER COMPRESSION SYSTEM
• No moving part except pump-motor, which is comparatively smaller than
compressor system.
• Quiet in operation, low maintenance cost.
• Can work only with thermal energy as an input.
• Can be built for huge working capacities. (even for above 1000 TR)
• Can be operated at designed C.O.P’s or even at part loads by varying generator
temperature.
• Space and Auto. control requirements favour absorption system.
12. DOMESTIC ELECTROLUX
REFRIGERATOR
• Developed from an invention by “Carl
Munters” & “Baltzer Von Platen”.
• Also known as “Three-fluid absorption
system” and “Munter’s Platen System”.
• Three fluids used are ammonia, hydrogen
and water.
Domestic Electrolux Refrigerator
13. PRINCIPLE & WORKING OF
ELECTROLUX REFRIGERATOR
Working cycle of Electrolux Refrigerator
14. POINTS WORTH NOTING
(FOR ELECTROLUX REF.)
• Complete cycle is carried out entirely
by flow of gravity of refrigerant.
• With this type of machine, efficiency is
not important since the energy input is
very small.
• Due to low C.O.P, it cannot be used
for industrial purposes.
ROLE OF HYDROGEN
• Helps in maintaining uniform total pressure
throughout the system.
• Permits the refrigerant to evaporate at low
temperature in evaporator, corresponding to
its partial pressure.
15. ADVANTAGES
(ELECTROLUX REF.)
• No pump/compressor required.
• No mechanical troubles, low
maintenance.
• No lubrication required, no wear-tear.
• Completely leak proof.
• Noiseless.
• Easy control, only by heat input.
• More complicated in construction and
working.
• Low C.O.P.
• If spoiled once, cannot be repaired and
has to be replaced fully.
DISADVANTAGES
(ELECTROLUX REF.)
16. REFERENCES
• Er. R.K. Rajput.Vapour Absorption Refrigeration Systems. Feb 03, 2014, “A textbook of
Refrigeration & Air-conditioning-2013”.
• Prof. M. Ramgopal. Various energy transfers in VARS (image). Feb 02, 2014, from
http://nptel.ac.in/courses/Webcourse-contents/IIT%20Kharagpur/Ref
• Prof. R. C. Arora. Domestic Electrolux Refrigerator (image). Feb 02, 2014, from
http://nptel.ac.in/courses/Webcourse-
contents/IIT%20Kharagpur/Ref%20and%20Air%20Cond/pdf