applications of refrigeration and airconditioning

1. Applications of RAC
By
Onkar V. Bichkar

2. Domestic refrigerator
• Preservation of food and reducing waste
• Storage temperature 00C -40C
• Single door double door refrigerant
• VCC and VAS R-12 or R-22
• 60-100mm Insulation glass fiber or thermo
Cole. For about 200mm for freezer

3. • Defrosting of refrigerant : -
• Manual defrosting: putting off refrigerator
• Push button: thermostat
• Double door refrigerator:-
general compartment:-natural cycle defrost
Amount of frost after defrost cycle can get collected
bellow evaporator
freezer compartment: manual defrosting
Temp. of frozen food should not go above frzeeing point so
defrosting is carryout when freezer is empty

4. • Control in refrigerator
• Starting relay: provide starting torque and
disconnect starting winding when motor speed
increases
• Overload Protector: Protect the compressor
motor winding from damage
• Thermostat: bulb of
thermostat charged with
refrigerant and it contracts
When particular temp.
reached

6. Water cooler
• Water available at constant temperature 70 -130C
irrespective of ambient temperature with the help of
thermostatic switch
• Storage type water cooler: evaporator coils are soldered
on to the walls of tank
• Tank may be galvanized steel or stainless steel sheet
• Reservoir of cold storage all the time
• Water level is maintained by float valve

7. • Instantaneous type water cooler: cylindrical wound coil
are bonded together by soldering
• Bottle type water cooler :
• Pressure type water cooler:
Self- contained remote :

8. Dairy
• Reduce bacterial growth
• Pasteurization of milk :
Water heating or steam heating (620)
• Cooling by chilled water (40 -50C)
• Fat content: formation of cheese (40C)
• Ice cream : pasteurization and homogenization
• Hardening

9. Food Preservation
What is food preservation?
Retaining food over a period of time without being
contaminated by pathogenic organisms or chemicals
and without losing its colour, texture, flavour and
nutritious value.
Why food preservation?
• Seasonal availability of food
• Different type of food at different locations

10. Food Product Average Useful
(days)
Storage life
0oC 22oC 38oC
Meat 6-10 1 < 1
Fish 2-7 1 < 1
Poultry 5-18 1 < 1
Dry meats and
fish
> 1000 > 350 &
< 1000
>100 &
< 350
Fruits 2 - 180 1 – 20 1 – 7
Dry fruits > 1000 > 350 &
< 1000
>100 &
< 350
Leafy vegetables 3 - 20 1 – 7 1 – 3

11. Advantages:
 Increases the shelf life of food
 Retain the quality of food – colour,
texture, flavour & nutrition value
 Increases food supply
 Adds variety to the food
 decreases wastage of food

12. Cold storage
• To store food products after processing
• Prefabricated insulated panels
• Air tight door in sandwich construction
• Safety anti-locking arrangement
• Temperatures – positive or sub-zero
• Layout – air lock, sorting-cum-intermediate storage
area, store compartments
• Important points – temperature, RH, air motion,
product mix, duration

13. Air handling unit
• Fresh air duct
• Return air duct
• Filter
• Cooling coil
• Heating coil

15. Types of Freezer
• Contact or plate freezer: hydraulic
piston compresses the packages of
product between plate
• Inlet freezer: Product is placed on top
of belt and brine refrigerant sprayed
bottom of belt

16. • Spiral freezer: increased belt
length compare to floor area it
allows product to remain for
longer time in freezer
• Air blast freezer: refrigerant
coil are located overhead fan
circulating the air over the
product at 50-150 m/min

17. Ice Plant
• Water treatment for making
ice: white and milky
appearance is due to air and
dissolved gasses that have to
be removed
• Brines:
 sodium chloride: used when
cooling surface should not
exposed to damage when
cooling occur
 calcium chloride: used shell
tubular cooler
• Brine temp maintained -120
to -70c and ammonia coil
temp -150c to -100c at 1.3-2
bar

18. • Freezing tank: constructed of 6mm steel plate,
water level below the brine level by 25mm
• Contains freezing coils equally distributed
through out the tank and submerged in brine
• Ice can: fabricated from galvanized sheet by
single riveting, they made heavy to avoid
floating

19. Evaporative cooling
• Cooling of air is result of
transferring sensible heat
of air to evaporative water.
This sensible heat is
transferred in the form of
latent heat
• Evaporative cooling
considered as adiabatic
system

20. Air conditioning
• Air conditioning is the process of altering the
properties of air (primarily temperature and
humidity) to more favorable conditions.
• More generally, air conditioning can refer to
any form of technological cooling, heating,
ventilation, or disinfection that modifies the
condition of air.

21. Types of air conditioning
• HVAC designer will recommend
different types of air conditioning
systems for different applications.
most commonly using are:
• 1)Window air conditioner: is the
most commonly used air
conditioner for single rooms. In this
air conditioner all the components,
namely the compressor, condenser,
expansion valve or coil, evaporator
and cooling coil are enclosed in a
single box. This unit is fitted in a
opening made in the wall of the
room, or more commonly a
window sill

23. 2) Split Air Conditioner:
• The split air conditioner comprises of two parts: the outdoor
unit and the indoor unit. The outdoor unit, fitted outside the
room, houses components like the compressor, condenser
and expansion valve. The indoor unit comprises the
evaporator or cooling coil and the cooling fan. For this unit
you don’t have to make any slot in the
wall of the room. Further, present day
split units have aesthetic appeal and
do not take up as much space as a window
unit. A split air conditioner can be used
to cool one or two rooms.

24. • Packaged Air Conditioner
• An HVAC designer will suggest this type of air conditioner
which is used to cool more than two rooms or a larger space
at home or office.
• There are two possible arrangements with the package unit.
In the first one, all the components, namely the compressor,
condenser (which can be air cooled or water cooled),
expansion valve and evaporator are housed in a single box.
• The cooled air is thrown by the high capacity blower, and it
flows through the ducts laid through various rooms. In the
second arrangement, the compressor and condenser are
housed in one casing. The compressed gas passes through
individual units, comprised of the expansion valve and
cooling coil, located in various rooms.

26. 4) Central Air Conditioning
System
• Central air conditioning is
used for cooling big
buildings, houses, offices,
entire hotels, gyms, movie
theaters, factories etc.
• If the whole building is to
be air conditioned, HVAC
engineers find that putting
individual units in each of
the rooms is very
expensive making this a
better option.

27. • A central air conditioning system is comprised
of a huge compressor that has the capacity to
produce hundreds of tons of air conditioning.
• eg. Hospital and multiplex