Thermodynamics of energy conservation and maintenance, Laws of Thermodynamics, First law of thermodynamics, Second law of thermodynamics, Kelvin - planck statement, Clausis statement, Reversible and irreversible process, Causes of irreversibility, Thermal Insulation, Classification Types of energy sources, Prime movers, Waste Heat Recovery, Source and Quality, Type of Waste Heat Recovery, Convective recuperators,Regenerator Maintenance,Breakdown maintenance,Planned Maintenance,Preventive Maintenance,Corrective Maintenance, Maintenance Audit, Steps of Maintenance Planning,Maintenance and Energy conservation,Friction,Types of Lubricant - Physical,Methods of lubrication,Energy efficient houseKeeping,Housekeeping – Water Reduction,Housekeeping – energy Reduction,Housekeeping – Waste Minimisation,Thermal Energy Audit(Energy Conservation in HVAC Systems),Energy Saving Tips,HVAC initiative,Interesting Facts,Quick wins, ASHRAE

1. Thermodynamics of energy
conservation and maintenance

2. • Thermodynamics is a branch
of physics concerned with heat transfer
and temperature and their relation
to energy and work.

3. Laws of Thermodynamics
• Zeroth law of thermodynamics: If two systems
are in thermal equilibrium respectively with a
third system, they must be in thermal
equilibrium with each other.

4. • First law of thermodynamics: energy can
neither be created nor be destroyed
Or
There is conservation of energy in nature
Internal energy of system = Net heat transferred into the system --
net work done by the system
• For a complex system
– Internal energy
– Electrical energy
– Mechanical energy

5. • Second law of thermodynamics: deals with
natural direction of flow of energy
– In a natural thermodynamic process, heat always
flow from hotter object to colder and a heat
engine can never be 100% efficient
– Kelvin - planck statement
– Clausius statement

6. • Kelvin - planck statement: It is impossible to
construct an engine whose sole purpose is to
convert heat energy from single thermal
reservoir into an equivalent amount of work
• Clausis statement: it is impossible for energy
in the form of heat to flow from at a lower
temperature to a body at higher temperature
without aid of external work.

7. Reversible and irreversible process
A+B C
A+B C

8. Causes of irreversibility
• Lack of equilibrium during process
– Transfer of heat
– Mixing of substances/ fluids having different
compositions
• Involvement of dissipative force
– friction
– Paddle wheel transfer work
– Flow of electricity through a resistor

9. • Third law of thermodynamics: It is impossible
to reduce the temperature of any system to
absolute zero

10. Thermal Insulation
• Thermal insulators are bad conductor of heat
• To maintain or control the temperature
• It is a material use to prevent heat loss or heat
gain in manufacturing process or restricted
covered space or buildings or specific purpose

12. Advantage of thermal insulation
• Economic by reduction in energy consumption
• Prevents corrosion
• Provide safety from fire/ accidents
• Reduce overall energy consumption
• By maintaining accurate control of
temperature, (provides quality output and
increased production)

13. Classification
• According to application
– Low temperature (<900C)
– Medium temperature (900C- 3250C)
– High Temperature (>3250C)
• According to material
– Organic
– inorganic

14. Low temperature
• <900C
• Material come under this category are
– Cork, wood, polystyrene, polyurethane
Application
– Refrigerators, cold and hot water system etc…

15. Medium temperature
• 900C- 3250C
• Material come under this category are
– Asbestos, calcium, silicate
Application
– Low temperature heating, steam raising
equipment, steam lines, flue ducts etc…

16. High temperature
• >3250C
• Material come under this category are
– Mica, silica or ceramic based insulators
Application
– Super heating systems, oven dryers and furnaces
etc…

17. Types of energy sources
• Primary and secondary energy
• Commercial and non commercial
• Renewable and non-renewable

18. Primary energy sources
• Primary energy is an energy form found in
nature that has not been subjected to any
conversion or transformation process
• It is energy contained in raw fuels

20. Prime movers
• Prime mover is an engine that converts fuel
to useful work
• May be steam turbine, reciprocating engine or
gas turbine

21. Waste Heat Recovery

22. What is Waste Heat?
• “Dumped” heat that can still be reused
• Waste heat is heat that has been generated in a
process by fuel combustion or a chemical
reaction, and then been “dumped” into the
environment even though it could still be reused
for some useful and economic purpose.

23. • “Value” (quality) more important than quantity
• The essential quality of heat is not the amount
but rather its “value”. The strategy of how to
recover this heat depends in part on the
temperature of the waste heat gases and the
economics involved.

24. • Waste heat recovery saves fuel
• Large quantity of hot flue gases is generated
from boilers, kilns, ovens and furnaces. If some
of this waste heat could be recovered, a
considerable amount of primary fuel could be
saved. The energy lost in waste gases cannot
be fully recovered. However, much of the heat
could be recovered and loss can be minimized
by adopting following measures as outlined in
this chapter.

25. Source and Quality

26. • High Temperature Heat Recovery
– This gives temperatures of waste gases from industrial
process equipment in the high temperature range.
• Medium Temperature Heat Recovery
– This gives the temperatures of waste gases from process
equipment in the medium temperature range. Most of the
waste heat in this temperature range comes from the
exhaust of directly fired process units
• Low Temperature Heat Recovery
– This includes some heat sources in the low temperature
range.

27. High Temperature Heat Recovery
Table: Typical waste heat temperature at high temperature
range from various sources
Types of Devices Temperature (0C)
Nickel refining furnace 1370 – 1650
Aluminium refining furnace 650 –760
Zinc refining furnace 760 – 1100
Copper refining furnace 760 – 815
Steel heating furnace 925 – 1050
Copper reverberatory furnace 900 – 1100
Open hearth furnace 650 – 700
Cement kiln (Dry process) 620 – 730
Glass melting furnace 1000 – 1550
Hydrogen plants 650 – 1000
Solid waste incinerators 650 – 1000
Fume incinerators 650 – 1450

28. Medium Temperature Heat
Recovery
Table: Typical waste heat temperature at medium temperature range
from various sources
Types of Devices Temperature (0C)
Steam boiler exhaust 230 – 480
Gas turbine exhaust 370 – 540
Reciprocating engine exhaust 315 – 600
Reciprocating engine exhaust (turbo
charged)
230 – 370
Heat treatment furnace 425 – 650
Drying & baking ovens 230 – 600
Catalytic crackers 425 – 650
Annealing furnace cooling systems 425 – 650

29. Low Temperature Heat Recovery
Source Temperature 0C
Process steam condensate 55-88
Cooling water from: Furnace doors 32-55
Bearings 32-88
Welding machines 32-88
Injection molding machines 32-88
Annealing furnaces 66-230
Forming dies 27-88
Air compressors 27-50
Pumps 27-88
Internal combustion engines 66-120
Air conditioning and refrigeration condensers 32–43
Liquid still condensers 32-88
Drying, baking and curing ovens 93-230
Hot processed liquids 32-232
Hot processed solids 93-232
Table: Typical waste heat temperature at low
temperature range from various sources

30. Type of Waste Heat Recovery
 Recuperators
• Heat exchange
between flue gases and
the air through
metallic/ceramic walls
• Ducts/tubes carry
combustion air for
preheating
• Waste heat stream on
other side
Inlet air from atmosphere
Outside
ducting
Tune plate
Preheated air
Centre tube plate
Exhaust gas from
process

31.  Metallic radiation
recuperators
• Simplest recuperator
• Two metal tubes
• Less fuel is burned per furnace
load
• Heat transfer mostly by radiation
• The radiation recuperator gets its
name from the fact that a
substantial portion of the heat
transfer from the hot gases to the
surface of the inner tube takes
place by radiative heat transfer.

32.  Convective recuperators
• Hot gas through parallel small
diameter tubes
• A second common
configuration for recuperators
is called the tube type or
convective recuperator. As
seen in this figure, the hot
gases are carried through a
number of parallel small
diameter tubes, while the
incoming air that is to be
heated enters a shell
surrounding the tubes and
passes over the hot tubes one
or more times in a direction
normal to their axes.

33.  Radiation/convective hybrid recuperators
• Combinations of radiation &
convection
• More effective heat transfer
• More expensive but less bulky
than simple metallic radiation
recuperators

34.  Ceramic recuperators
• Less temperature limitations:
• Operation on gas side up to 1550 ◦C
• Operation on preheated air side to 815 ◦C
• New designs
• Last two years
• Air preheat temperatures <700◦ C
• Lower leakage rates

35. Regenerator
• Large capacities
• Glass and steel melting
furnaces
• Time between the
reversals important to
reduce costs
• Heat transfer in old
regenerators reduced by
•Dust & slagging on
surfaces
•heat losses from the
walls

36. Heat Wheels
• Porous disk rotating
between two side-by-
side ducts
• Low to medium
temperature waste
heat recovery systems
• Heat transfer
efficiency up to 85 %

37. Heat Pipe
• Transfer up to 100
times more thermal
energy than copper
• Three elements:
- sealed container
- capillary wick
structure
- working fluid
• Works with
evaporation and
condensation

38. Economizer
• Utilize the flue gas heat for
pre-heating the boiler feed
water
• In the case of boiler systems,
an economizer can be
provided to utilize the flue gas
heat for pre-heating the boiler
feed water. On the other hand,
in an air pre-heater, the waste
heat is used to heat
combustion air. In both the
cases, there is a
corresponding reduction in
the fuel requirements of the
boiler.

39. Economizer
 Shell and tube heat exchanger
• Used when the medium containing waste heat is a
liquid or a vapor that heats another liquid
• Shell contains
the tube bundle,
and usually
internal baffles
to direct the
fluid
• Vapor
contained within
the shell

40. Type of Waste Heat Recovery
Plate Heat Exchanger
• Parallel plates forming a thin flow pass
• Avoids high cost of heat exchange surfaces
• Corrugated
plates to
improve heat
transfer
• When directions
of hot and cold
fluids are
opposite, the
arrangement is
counter current

41. Plate Heat Exchanger
 Run around coil exchanger
• Heat transfer from hot
to colder fluid via heat
transfer fluid
• One coil in hot stream
• One coil in cold stream

42. Type of Waste Heat Recovery
Plate Heat Exchanger
 Waste heat boiler
• Water tube boiler: hot
exhaust gases pass
over parallel tubes
with water

43. Maintenance

44. Definition
• Routine recurring process of keeping a
machine or process in its operating condition
so that it can be utilized to its full designed
capacity and efficiency for maximum length of
time.

45. INTRODUCTION
• The design life of each equipments requires
periodic maintenance.
• The objectives of maintenance management are ---
 To maintain the equipments in its best operating condition with
economical cost.
 Extending the life of the equipment to its design.
• Types of Maintenance Management are –
– Breakdown or Reactive Maintenance,
– Planned

46. Maintenance
Planned
Preventive Predictive Corrective
Breakdown

47. Break downmaintenance
• Emergency Policy
• In which plant or equipment is operated until
it fails

48. Breakdown Maintenance
 Run it till it breaks Maintenance Mode.
Advantages:---
 Low investment cost for Maintenance.
 Less staff is required.
Dis--advantages:---
 In-efficient use of staff.
 Waiting for the equipment to break is responsible for shortening of the life of
the equipment causes more frequent replacement with high replacement cost.
 To repair the critical piece of equipment and to bring it in action very quickly,
the maintenance overtime cost occurs.
 Primary equipment damage due to absence of Preventive Maintenance causes
also Secondary equipment or Process damage ensuring more additional costs.

49. Planned Maintenance
• To avoid random failure

50. Preventive Maintenance
 Actions performed on a time or machine run based schedule that detect,
preclude or mitigate degradation of a component or system with the aim of
sustaining or extending its useful life through controlling degradation to an
acceptable level.
Advantages:-
 Equipment life is
extended and its
reliability increased.
 Energy savings.
 12%-18% cost savings
over breakdown
Maintenance program.
 Decrease cost of
replacement
 Flexibility of
maintenance
Dis-advantages:-
 Performance of unneeded
Maintenance.
 Potential for incidental damage
to components in conducting
unneeded Maintenance.

51. Steps involved in preventive
maintenance
• Maintenance survey: list of equipment
required maintenance
• Maintenance Schedule: prepare schedule
sheet
• Records of Repairs: necessary data of repair or
replacement for further use

52. Predictive Maintenance
• Predictive Maintenance differs from the Preventive Maintenance based
on the Maintenance need on the actual condition of machine rather than
on some pre-set schedule
Advantages:-
 Increased component life.
 Decrease in costs for parts and
labour.
 Better product quality.
 Energy savings.
 Improved worker and
environmental safety.
 Estimated 8%-12% cost savings
over Preventive Maintenance
program.
Dis-advantages:-
 Increased investment in
staff training.
 Savings potential not
readily seen by
management.

53. Corrective Maintenance
• The maintenance done to avoid reoccurrence
of such repetitive failures

54. Maintenance Audit

55. Maintenance Planning
• Maintenance Planning is done to find the
answer of What & how is the job and where
the job is to be done.
• It is depended on the Efficiency and Cost of
action.
• Persons involved in Maintenance Planning
should have the Knowledge about jobs,

56. Steps of Maintenance Planning
 The main steps to be followed for proper Maintenance Planning are --------
 Knowledge Base:- It includes knowledge about equipment, job,
available techniques, materials and facilities.
 Job Investigation at the site:-It gives the clear perception of the total
jobs.
 Identify and Document the work:-Knowing the earlier two steps and
knowing the needs of Preventive , Predictive and other Maintenance jobs.
 Development of repair plan:-Preparation of step by step procedures
which would accomplish the work with the most economical use of time,
manpower and material.
 Preparation tools and facilities list indicating the needs of special tools,
tackles and facilities needed.
 Estimation of time required to do the job with work measurement
technique and critical path analysis.

57. Maintenance Scheduling
Scheduling is the function of coordinating all of
the logistical issue around the issues regarding
the execution phase of work.

58. Maintenance and Energy conservation
• Enhances the efficiency of equipment keeping
them running more efficiently
• Increased reliability
• Improved productivity
• Reduced cost
• 25% energy used in world lost through friction
• In turn causes wear and tear, which impact
consumption level
• 10% energy consumption is used to overcome
friction

59. Friction

60. Introduction
• Friction can be defined as the resistance to relative motion
between two bodies in contact, under normal load
• Lubrication is the process or technique employed to reduce
friction between, and wear of one or both, surfaces in close
proximity and moving relative to each other, by interposing a
substance called a lubricant between them.
– The lubricant can be a solid, (e.g. Molybdenum disulfide MoS2) a
solid/liquid dispersion, a liquid such as oil, a liquid-liquid dispersion
(a grease)

61. Types of Lubricant - Physical
• Liquid
• Solid
• Semi solid
• Gases

62. Types of Lubricant - Physical
• Liquid
• Typical lubricants are liquid/fluids
• Mineral oil or synthetic oils
• Solid
• Graphite, MoS2
• Semi solid
• Greases
• Gases
• Atomised 2 stroke oils

63. • http://www.mecheng.iisc.ernet.in/~bobji/funt
ri/assign/Lubricants.htm

64. Typical lubricants - Application
• Engine oils
• Gear Oils
• Turbine Oils
• Hydraulic Oils
• Metal working oils
• Cutting oils
• Forming Oils
• Rust preventives

65. Methods of lubrication
• Hydrodynamic Lubrication or Thick Film
Lubrication
• Hydrostatic Lubrication
• Boundary Lubrication or Thin Film Lubrication

66. • Hydrodynamic Lubrication or Thick Film
Lubrication
– Hydrodynamic lubrication is said to exist when the
moving surfaces are separated by the pressure of
a continuous unbroken film or layer of lubrication.
In this type of lubrication, the load is taken
completely by the oil film.

67. • Hydrostatic Lubrication
– Hydrostatic lubrication is essentially a form of
hydrodynamic lubrication in which the metal
surfaces are separated by a complete film of oil,
but instead of being self-generated, the separating
pressure is supplied by an external oil pump

68. • Boundary Lubrication or Thin Film Lubrication
– Boundary lubrication exists when the operating
condition are such that it is not possible to
establish a full fluid condition, particularly at low
relative speeds between the moving or sliding
surfaces.

69. Energy efficient house Keeping

70. Housekeeping – Energy Reduction
– Turn off unnecessary equipment in guest rooms
i.e.
– lights
– TVs (do not leave them on standby)
– air conditioning / heaters
– if these must be left on then adjust to a
suitable temperature
• 26OC when cooling,
• 18OC when heating
• Check for poorly fitting doors, windows,
draughts etc. and report to maintenance

71. Housekeeping – Water Reduction
– Don’t leave taps running while cleaning
– Check for malfunctioning toilets, excessive
water flow, leaking plugs
– Report any issue to maintenance
immediately for prompt repairs
– If there is a towel / linen reuse programme in
place then ensure it is followed
– Consider implementing top to bottom
method of linen change if appropriate

72. Housekeeping – Waste Minimisation
– Use bins that do not require a plastic bag
liner
– If a plastic liner is used, only replace when
soiled or damaged
– Collect any recyclables from guest rooms
separately to general waste
– Use refillable amenity dispensers
– If small disposable ones are currently in
place, only replace partially used bottles
on checkout

73. Case Study - Caribbean
– Pirate’s Inn, Barbados
– Action
– The hotel has implemented a policy where
all lights and air conditioning is turned off
in unoccupied rooms
– Guests pay an additional $10 per day for
air con usage and are advised of the policy
on arrival
– Impacts
– The hotel reduced energy consumption by 5.4% in 2010 compared to previous
consumption levels saving over 5,000 kWh annually and reducing CO2 emissions
by 4 tonnes

74. Action Planning
• Discuss what options there are for
reducing energy, water and waste in
your operations
– create a list of potential actions
– who needs to be involved to ensure
that these actions can take place?
– how quickly do you anticipate these
actions being put into place?
– will any further training be required?

75. Thermal Energy Audit
(Energy Conservation in HVAC
Systems)

76. Introduction
• Heating, ventilation and air conditioning (HVAC)
is essential in most settings to ensure a pleasant,
comfortable and safe work environment
• HVAC typically accounts for 40-50 percent of the
total energy bill for businesses and commercial
buildings
• Significant energy saving design and equipment
opportunities are available when constructing new
buildings, but several possibilities to improve
heating and cooling performance can also be
achieved in existing systems.

77. Energy Saving Tips
• Short term
• Long term

78. Quick wins
 Use only when and where necessary: Ensure HVAC systems are turned off when the building is not occupied, for
example overnight and during weekends.
 Keep your employees informed: Encourage employees to ensure doors, windows and the like are closed when
appropriate and that they are aware of the implications and benefits of adopting different behaviours and initiatives.
 Adjust the temperature after season. For maximum comfort, the temperature of rooms should be 24-25°C in
summer and 18-20°C in winter. Additional heating or cooling results in energy wastage. Infrequently used rooms such
as toilets and storerooms can be set to 16°C in winter, saving on heating costs for these areas by around 30 percent.
 Section off unused areas. When heating or cooling, ensure both vents and thermostats in unoccupied areas are
sectioned off to avoid energy wastage.
 Use fans. Temperature, humidity, and air movement all affect the comfort of a room. The use of fans can therefore
reduce the need for air conditioning allowing for a temperature setting of three to five degrees higher being as
comfortable with fans.
 Avoid peak demand periods. By adjusting workplace schedules and reducing energy use during peak demand
periods, savings can be made on air conditioning, lighting and other electricity use.
 Maintain filters. HVAC filters should be maintained or changed on a regular basis as Energy Efficiency Fact Sheet:
Heating, ventilation & Air Conditioning recommended by the manufacturer, which can be as frequently as monthly
during peak cooling or heating seasons. Proper filter maintenance will help avoid energy wastage and overwork of
equipment.
 Maintain the system. All HVAC equipment needs to be maintained on a regular basis to ensure efficient operations,
reliability and long life. Proper maintenance can save up to 10 percent of space conditioning energy usage.
 Ensure the maintenance program includes the cleaning of condenser coils and evaporators, change of belts and filters,
fix of duct leaks. Also check for proper economiser operation and adequate refrigerant levels. Further, old and inferior
valves, steam traps and other low cost parts can waste large amounts of energy if not replaced.

79.  Use timers. Air conditioning, ventilation and heating hours can be reduced by
using switches and timers ensuring all HVAC systems are turned off when the
building is unoccupied.
 Install thermostat. Programmable thermostats can be used to automate HVAC
systems. The thermostat ensures the HVAC system turns on half an hour before
arrival and turns the system off half an hour before leaving. This avoids heating or
cooling unoccupied space which is the case with older type thermostats that control
the system based on temperature. This inexpensive investment can save HVAC
related energy costs by as much as 30 percent4. Ensure a locking cover is used to
prevent tampering with thermostat settings.
 Avoid unnecessary lighting. Turning off lights in unused areas and replacing
incandescent light bulbs with compact fluorescent light (CFL) globes may not only
result in lower electricity usage but also in less heat being emitted, saving on air
conditioning and ventilation running costs.
 Use energy efficient office equipment. Selecting efficient office equipment and
electronics can help to ensure minimum heat output. Coupled with turning off
equipment when not in use can yield significant savings.

80. Long Term
 Avoid over sizing. Over sizing HVAC equipment will result in unnecessary investment as well as
operation costs. Ensure a proper and well configured system is in place.
 Consider energy recovery. An energy recovery ventilation system can be used to take advantage of
waste energy from the exhaust air stream by using it to condition the incoming fresh air.
 Use radiant heating where suitable. Areas such as warehouses, garages, patios and waiting areas
can be beneficial to heat using radiant heating. With this method, objects are being heated rather than
the air which requires less energy.
 Insulate buildings. By insulating roof spaces, ceilings, walls and pipes, loss of heat during the
winter and gain of heat during the summer can be reduced, mitigating the need for heating and
cooling. Ensure hot as well as cold air ducts are insulated and do not leak.
 Avoid losses through windows. As much as 40 percent of the heat lost during the winter and up to
50 percent of unwanted heat gain during the summer is through windows. The use of double-glazing
windows can dramatically reduce heat loss during winter and also the amount of heat entering during
the summer period.
 The use of shades, drapes, blinds and tinting can also be used to prevent solar entry and air-
conditioning loss during the summer. Keep drapes and shades open during winter days to allow the
sun to warm the building and closed during night to prevent possible draught and heat loss.

81.  Skylights can be used to allow natural light to enter which will save on both lighting and heating. These can be
covered during the summer months to avoid the need for additional air conditioning.
 Ensure use of energy efficient systems. When replacing HVAC systems, consider high-efficiency units. By
replacing fan and pump motors and other equipment with premium efficiency models, as much as 35 - 45
percent can be saved on the annual investment. Modern high efficiency HVAC systems use up to 40 percent
less energy than older systems.
 Consider variable speed drives. By installing variable speed drives (VSDs) on air conditioning fans, the speed
of the fan motors can be controlled to match the amount of air needed to be moved throughout your building
and therefore reduce energy use and operation costs if the compressor powers down accordingly. VSDs can
save 30 - 40 percent on the investment annually.
 Utilise waste heat. For facilities that have heat-generating processes such as cooking, or onsite distributed
generation equipment, consider heat recovery as a way to capture free waste heat and use it to offset facility
heating and cooling costs.
 Use dehumidification in humid climates. In humid climates the use of a dehumidification system can provide
increased comfort at higher temperatures, allowing for use of smaller HVAC equipment.
 Install economisers. Energy can be saved during days when the outside temperature is lower than the inside
temperature by using economisers. These take fresh air from the outside for cooling rather than using
refrigeration equipment to cool recirculated air.
 Implement an energy management system. Energy management systems can be useful when the air
conditioning system is too complex to control with timers or thermostats. The system allows for the use of
different cooling temperatures for different zones, optimum equipment start and stop times etc. Energy
management systems can save 30 to 40 percent on annual investment.
 Invest in green energy. Choosing Government accredited Origin Green Power for your business can benefit
everyone and is one of the simplest things your business can do to reduce its impact on our environment. We
give you the choice of accredited new renewable energy from environmentally friendly sources such as solar
and wind energy

83. HVAC initiative
• ASHRAE was formed as the American Society of
Heating, Refrigerating and Air-Conditioning
Engineers
• by the merger in 1959 of American Society of Heating and Air-
Conditioning Engineers (ASHAE) founded in 1894 and The
American Society of Refrigerating Engineers (ASRE) founded in
1904.
• Mission:
To advance the arts and sciences of heating,
ventilating, air conditioning and refrigerating to
serve humanity and promote a sustainable world.

84. Interesting Facts
• HVAC typically accounts for 40-50 percent of the
total energy bill for businesses and commercial
buildings.
• By leaving a door open, up to 50 percent of HVAC
energy costs can be wasted.
• Every one degree temperature increase in winter
will increase energy use by 15 percent.
• Every one degree temperature decrease in
summer will increase energy use by 10 percent.