complete description about working of refrigerator and its construction

2. INTRODUCTION
WORKING PRINCIPLE
CONTSRUCTION
COEFFICIENT OF
PERFORMANCE
USES
ADVANTAGES AND
DISADVANTAGES

3. INTRODUCTION
Device that transfers heat from inside it to its
external environment
Maintain temperature lower than its
environment

4. Sink at lower
temperature T2,
heatQ2
Working
substance
Source at higher
temperature
T1,heat Q1
Electrical power
Acc. first law of
thermodynamics:
dQ=dU+dW
Q2-Q1=W

5. THROTTLING DEVICE
Converts high pressure liquid
to low pressure liquid
Decreases temperatures
EVAPORATOR
Act as exchanger of
energy for vapour formed
during passing through
the body

6. COMPRESSOR
Raise the pressure
to initial value for
continuation of
refrigeration cycle
CONDENSER
Fitted outside the body
convert vapour,which is
formed during raising
pressure into liquid for
continuation of refrigeration

7. DEFINATION: it is ratio of quantity of heat removed
From the contents of refrigerator to energy
spent per cycle.
β = Q2 /Q1-Q2 in a carnot cycle { Q2/Q1=T2/T1}
=T2/T1-T2
Where Q1 is heat absorbed and Q2 is heat removed per cycle
T1,T2 are respectively temperature of source and sink

8. Fins of condenser and evaporator
External work on system
T1-T2 must be small
Defrosting must be there

9. STORAGE OF FOOD
EXTEND SHELF LIFE
OF PERISHABLE FOOD
PREVENT SPOILAGE OF FOOD
IN HOSPITALS USED FOR STORAGE
OF HEAT –SENSTITIVE DRUGS
USED TO COOL FOOD AND DRINKS

10. ELECTRICITY CONSUMPTION
REFRIGERANT USED IS NOT
ECOFRIENDLY
MULTIPLICATION OF BACTERIA
PRODUCTION AFTER STORAGE