1. 20CE7020E
BUILDING SERVICES
REFRIGERATION
PRINCIPLES
UNIT – 4

2. UNIT 4 REFRIGERATION PRINCIPLES
Heat emitters - Expansion facilities of heating
system - Energy management system - Factors
affecting fuels-Oil sand properties of natural gas -
Air conditioning, principles and applications -
Refrigerant and system characteristics – Heat
recovery devices.

3. DEFINITION
• A refrigerator is an equipment used to remove
heat continuously from a space and maintain its
temperature below that of the atmosphere
temperature.

4. CLASSIFICATION OF REFRIGERATION SYSTEMS
1. Air refrigeration system
2. Ice refrigeration system
3. Vapour refrigeration system
a. Vapour compression refrigeration system
b. Vapour absorption refrigeration system
4. Special refrigeration system
a. Mixed refrigeration system
b. Thermo- electric refrigeration system
c. Steam jet refrigeration system
d. Vortex tube refrigeration system

5. Coefficient Of Performance (C.O.P):
It is defined as the ratio of heat extracted in a given
refrigerating effect to the work input.
Refrigerating effect
C.O.P of refrigerator =
Work input
C.O.P of heat pump = 1+ C.O.P of refrigerator.

6. COMMON REFRIGERANTS
The common refrigerants available at reasonable costs
are ammonia, carbon di-oxide, methy1 chloride and
Freon-12.
Freon-12 is a fluorocarbon of methane series. There are
number of Freon refrigerants namely
F-11, F-13, F21 and F-22 is readily available and cheaper
than others.
No refrigerant has all the desirable properties. However,
F-12, ammonia and carbon di-oxide are used commonly
for very low temperature work because of low boiling
points.

7. PROERTIES FOR A GOOD REFRIGERANT
• Non-toxic.
• Non-flammable and non explosive.
• Non-corrosive to metals.
• Non irritant to human body.
• Not having objectionable odour.
• Do not affect the stored food products.
• Do not react with lubricant oils.

8. VAPOUR COMPRESSION REFRIGERATION
• Compressor.
• Condenser.
• Receiver.
• Expansion
valve or
Throttle valve.
• Evaporator.

9. VAPOUR ABSORPTION SYSTEM

10. DOMESTIC REFRIGERATOR

11. Unitary Air Conditioning System
• In this system different component of air
conditioning system is manufactured and
assembled as a unit in a factory. This unit is
installed in or near to space to be conditioned.
Example
• Window air conditioner
• Split air conditioner

12. WINDOW AIR CONDITIONING

13. SPLIT TYPE ROOM AIR CONDITIONER

14. Heating Systems in buildings
• Building heating systems are used for increasing
the temperature of a space in buildings or
industrial processes.
A heating process is primarily achieved by
•free convection (electric heaters, radiator, etc.),
•forced convection (fan coils, forced air over a heat
exchanger in furnace, etc.), and
•radiation heat transfer (radiators, electric radiative
heaters, etc.).

15. Heat emitters
• Heating, process and system of raising the
temperature of an enclosed space for the
primary purpose of ensuring the comfort of the
occupants.
• By regulating the ambient temperature, heating
also serves to maintain a building’s structural,
mechanical, and electrical systems.
• Heat emitters are used to distribute heat around
a building to maintain required set points within
spaces.

16. Types of Heat emitters
• Radiators
• Warm Air Heaters
• Radiant Heaters
• Under-floor Heaters
• Electrical Heaters

17. Coefficient of Thermal Expansion
• Its a measures of fractional
change in size per degree
change in temperature at a
constant pressure
Expansion facilities of heating system

18. Failure of metal due to having Different CTE
• Failure to match CTE can cause the heated
system to damage itself. When materials with
different CTE are used together in the same
heated application, they may experience failures
such as fretting, galling, bending, cracking or
warping.

19. Energy management

20. objective of Energy Management
• To achieve and maintain optimum energy
procurement and utilization, throughout the
organization
 To minimize energy costs / waste without
affecting production & quality
 To minimize environmental effects.

21. Fossil fuels
• Fossil fuels are natural fuels formed by the
decomposition, heating, and pressurization of
buried phytoplankton and zooplankton (not
dinosaurs). It is called “fossil” fuel because it’s
found buried in the ground, not because it
contains fossils. Like wood and biodiesel, fossil
fuels are rich in carbon. But, fossil fuels are
considered a type of non-renewable energy
because they take millions of years to form.

22. Problems With Fossil Fuels
• They aren’t renewable. When we run out, we’re out (for
the next few million years).
• Burning them dumps huge amounts of carbon dioxide
and other greenhouse gases into the air, driving global
warming.
• Obtaining and refining them damages ecosystems.
Unearthing and transporting fossil fuels disrupts
landscapes. Many processes release toxic wastes into the
environment.
• Burning fossil fuels leads to air pollution. Some refined
fuels burn cleanly, but others produce soot and harmful
combustion products.

23. Problems
• Global Warming Pollution
•Rapid increase of heat on the surface of the Earth.
• Higher Rise in the Sea Level
• Pole region ice melting Cause Sea level increase which affect
small islands
• Other Forms of Air Pollution
• many harmful pollutants are formed such as nitrogen
oxides (NOx), carbon monoxide (CO), volatile organic
compounds (VOCs), particulate matter, lead, mercury,
and sulphur dioxide (SO2).
• Toxic Gases Causing Acid Rain
• The gases from cars, trucks, and buses release
nitrogen oxides and sulphur dioxide into the air.
These pollutants cause acid rain by the wind.

24. Oil Spills
• Crude oil or petroleum is often
transported from one place to another by
tankers and ships. Any leakage in these
tankers causes oil spills. This issue can
lead to water pollution and poses a
problem for marine life.

25. Ocean Acidification
• When we burn crude oil, coal, and gas, we
change the ocean’s basic chemistry, making it
more acidic.
• Our seas absorb as much as a quarter of all
carbon emitted.
• Since the start of the Industrial Revolution and
our fossil fuel-burning ways, the ocean has
become 30 per cent more acidic.

26. Oil sand properties of natural gas
Bitumen is a
sticky, black,
highly viscous
liquid or semi-
solid form of
petroleum.

27. • Oil sands deposits found elsewhere in the
world are oil-wet, so the solids want to stay
with the oil phase, and can't be separated
from bitumen using just water.
• Those deposits typically need chemicals,
usually solvents, to strip the sand away from
the bitumen.

28. Heat recovery devices
• Industrial furnaces are used for carrying out
certain processes which requires heat. Heat in the
furnace is provided by
(i) Fuel energy,
(ii) Chemical energy,
(iii) Electrical energy or
(iv) A combination of these energies.

29. Methods for waste heat recovery
(i) Transferring heat between exhaust gases and
combustion air for its preheating,
(ii) Transferring heat to the load entering furnaces,
(iii) Generation of steam and electrical power, or
(iv) Using waste heat with a heat pump for
heating or cooling facilities.

30. The benefits Heat Recovery Devices
(i) Saving of fuel,
(ii) Generation of electricity and mechanical work,
(iii) Reducing cooling needs,
(iv) Reducing capital investment costs in case of new
facility,
(v) Increasing production,
(vi) Reducing greenhouse gas emissions, and
(vii) Transforming the heat to useful forms of energy.

31. Typical WHRDS used for
• air preheating include recuperators,
• furnace regenerators,
• recuperative and regenerative burners, passive air
preheaters,
• shell and tube heat exchangers,
• finned tube heat exchangers
• or economizers,
• rotary regenerator or heat wheel,
• preheating of load,
• waste heat boilers,
• and heat pumps.

32. Recuperators
A recuperator is a type of heat exchanger that has
separate flow paths for each fluid throughout its
passages and heat is transferred through the
separating walls.

33. Principle of
recuperation
and different
types of
recuperators

34. Regenerators with furnace

35. Cross sections of recuperative and
regenerative burners

36. Regenerative Burner
Alumina Ball is also used as heat exchange media

37. Recuperative burner

38. metallic recuperator

39. Passive Plate type Pre-heater

40. Heat Pipe Type Heat Exchanger

41. Rotary regenerator or a heat wheel

42. Continuous Pusher Type Reheating
Furnace

43. Two Pass Water
Heat Boiler