Energy Audit in Building A Regional Training Workshop 1 - 5 June, 2010

1. RCREEE Energy Audit in Building
RCREEE Energy Audit in Building
Training Course Program
Tunis, 1st – 5th June 2010
Energy audit of air‐conditioning and
cooling systems
by
Adel Mourtada

2. Content
- Refrigeration cycle
- AC/Refrigeration Systems and
Components
-Type of refrigeration
- Assessment of refrigeration and AC
-Energy Efficiency Measures
Energy
-Energy Audit of HVAC System in
Commercial Building Utilities
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3. Typical
Refrigeration
Cycle
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4. Thermodynamic Cycle
Thermodynamic Cycle
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5. - Refrigeration cycle
- AC/Refrigeration Systems and
Components
-Type of refrigeration
- Assessment of refrigeration and AC
- Energy Efficiency Measures
- Energy Audit of HVAC System in
Commercial Building Utilities
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6. Components
• R fi
Refrigerant
• Evaporator/C
hiller
hill
• Compressor
• Condenser
• Receiver
• Thermostatic
expansion
valve (TXV)
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7. Compressors
There is a large variety of
compressors. Some of variations
p
are:
The compressor manufacturer
Piston, vane, or scroll type
The piston and cylinder
arrangement
How the compressor is mounted
Style and position of ports
Type and number of drive belts
Compressor displacement
Fixed or variable displacement
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8. Evaporator Types
Evaporator Types
Plate evaporators, top, are
a series of stamped
aluminum plates that are
aluminum plates that are
joined together. Tube and
fin evaporators, bottom,
fin evaporators, bottom,
have tubes for the
refrigerant that are joined
to the fins.
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9. Refrigerant
• Desirable properties:
Desirable properties:
– High latent heat of vaporization ‐ max cooling
– Non toxicity (no health hazard)
Non‐toxicity (no health hazard)
– Desirable saturation temp (for operating pressure)
– Chemical stability (non flammable/non explosive)
Chemical stability (non‐flammable/non‐explosive)
– Ease of leak detection
– Low cost
– Readily available
• Commonly named “FREON” (R 114, etc.)
Commonly named FREON (R‐114, etc.)
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10. Condenser Types
Condenser Types
Condensers A and C are
round tube, serpentine
condensers.
Condenser B is an
C d Bi
oval/flat tube, serpentine
condenser.
Condenser D is an
oval/flat tube, parallel
flow condenser.
Flat tube condensers are
more efficient.
ffi i t
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11. Expansion Devices
Expansion Devices
• The expansion device separates the high
side from the low side and provides a
id f h l id d id
restriction for the compressor to pump
against.
• There are two styles of expansion
y p
devices:
‐ The TXV can open or close to change
flow. It is controlled by the superheat
spring, thermal bulb that senses
spring, thermal bulb that senses
evaporator outlet temperature, and
evaporator pressure
‐ The OT is a tubular, plastic device with a
small metal tube inside. The color of the
small metal tube inside The color of the
OT is used to determine the diameter of
the tube. Most OT have a fixed diameter
orifice.
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12. AC Systems
AC options / combinations:
• Air Conditioning (for comfort / machine)
g( )
• Split air conditioners
• Fan coil units in a larger system
• Air handling units in a larger system
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13. Refrigeration systems
• Small capacity modular units of direct
expansion type (50 Tons of Refrigeration)
• Centralized chilled water plants with
chilled water as a secondary coolant (>50
TR)
13
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14. Refrigeration at large Commercial
Buildings
• Bank of units off-site with common
• Chilled water pumps
p p
• Condenser water pumps
• Cooling towers
• More levels of refrigeration/AC, e.g.
• Comfort air conditioning (20-25 oC)
• Chilled water system (5 – 10 oC)
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15. - Refrigeration cycle
- AC/R f i
AC/Refrigeration S t
ti Systems and
d
Components
-Type of refrigeration
- Assessment of refrigeration and AC
g
-Energy Efficiency Measures
-Energy Audit of HVAC System in
Commercial Building Utilities
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16. Type of refrigeration
Refrigeration systems
R fi ti t
• V
Vapour CCompression
i
Refrigeration (VCR): uses
mechanical energy
• Vapour Absorption Refrigeration
(VAR):
(VAR) uses thermal energy
th l
16
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17. Type of refrigeration
Vapour Compression Refrigeration
Choice f
Ch i of compressor, design of
d i f
condenser and evaporator determined
by:
• Refrigerant
• Required cooling
• Load
• E
Ease of maintenance
f i t
• Physical space requirements
• A il bilit of utilities (water, power)
Availability f tiliti ( t )
17
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18. What’s Solar Cooling?
g
• The core idea is to use the solar energy directly to
gy y
produce chilled water.
• The high temperature required by absorption
chillers is provided by solar troughs.
p y g
• The system doesn’t require “High Technology”
materials (like in PV systems) and has peak
p
production in the moment of peak demand.
p
Chilled water Heat
Transfer Fluid
Transfer Fluid
Sustainable Architecture Applied to Replicable
Public Access Buildings
www.sara‐project.net
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19. System combined to sub floor exchanger
System combined to sub‐floor exchanger
Sustainable Architecture Applied to Replicable
Public Access Buildings
www.sara‐project.net
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20. Type of refrigeration
Evaporative Cooling
• Air in contact with water to cool it close to ‘wet
bulb temperature’
• Advantage: efficient cooling at low cost
• Disadvantage: air is rich in moisture
Sprinkling
Water
Hot Air Cold
Air
20
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21. Type of refrigeration
Main Features of Cooling Towers
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22. Type of refrigeration
Components of a cooling tower
• Frame and casing: support exterior
enclosures
• Fill: facilitate heat transfer by
maximizing water / air contact
i i i t i t t
• Splash fill
• Film fill
• Cold water basin: receives water at
bottom of tower
22
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23. Type of refrigeration
Components of a cooling tower
• Drift eliminators: capture droplets in
air stream
• Air inlet: entry point of air
• Louvers: equalize air flow into the fill
and retain water within tower
• N
Nozzles: spray water t wet th fill
l t to t the
• Fans: deliver air flow in the tower
23
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24. Type of refrigeration
Mechanical Draft Cooling Towers
• Large fans to force air through
circulated water
• Water falls over fill surfaces:
maximum heat transfer
• Cooling rates depend on many
parameters
• Large range of capacities
• C b grouped, e.g. 8-cell tower
Can be d 8 ll t
24
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25. Type of refrigeration
Forced Draft Cooling Towers
F d D ft C li T
• Air blown through tower
g
by centrifugal fan at air
inlet
• Advantages: suited for
high air resistance & fans
are relatively quiet
• Disadvantages:
recirculation due to high
air entry
air-entry and low air exit
air-exit
velocities
25
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26. - Refrigeration cycle
- AC/R f i
AC/Refrigeration S t
ti Systems and
d
Components
-Type of refrigeration
- Assessment of refrigeration and AC
g
-Energy Efficiency Measures
- Energy Audit of HVAC System in
Commercial Building Utilities
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27. Assessment of Refrigeration
• Cooling effect: Tons of Refrigeration
1 TR = 3024 kCal/hr heat rejected
• TR is assessed as:
TR = Q x⋅Cp x⋅ (Ti – To) / 3024
p ( )
Q= mass flow rate of coolant in kg/hr
Cp = is coolant specific heat in kCal /kg deg C
Ti = inlet, temperature of coolant to evaporator (chiller) in 0C
To
T = outlet t
tl t temperature of coolant from evaporator (chiller) i 0C
t f l tf t ( hill ) in
27
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28. Assessment of Refrigeration
Specific Power Consumption (kW/TR)
• Indicator of refrigeration system s
system’s
performance
• kW/TR of centralized chilled water
system is sum of
• Compressor kW/TR
• Chilled water pump kW/TR
• Condenser water pump kW/TR
p p
• Cooling tower fan kW/TR
28
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29. Assessment of Refrigeration
Coefficient f Performance (COPCarnot)
C ffi i t of P f
• Standard measure of refrigeration efficiency
• Depends on evaporator temperature Te and
condensing temperature Tc:
COPCarnot = Te / (Tc - Te)
• COP calculated for type of compressor:
Cooling effect (kW)
COP =
Power input to compressor (kW)
29
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30. Assessment of Air Conditioning
g
Measure
• Airflow Q (m3/s) at Fan Coil Units (
( ) (FCU) or Air
)
Handling Units (AHU): anemometer
• Air density ρ (kg/m3)
• Dry bulb and wet bulb temperature: psychrometer
• Enthalpy (kCal/kg) of inlet air (hin) and outlet air
(Hout) psychrometric charts
): h ti h t
Calculate TR Q × ρ × (h in − h out )
TR =
3024
30
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31. Assessment of Ai C diti i
A t f Air Conditioning
Indicative TR load profile
• Small office cabins: 0.1 TR/m2
• Medium size office (10 – 30 people
occupancy) with central A/C: 0.06
TR/m2
• Large multistoried office complexes
with central A/C: 0 04 TR/m2
0.04
31
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32. Considerations for Assessment
• Accuracy of measurements
• Inlet/outlet temp of chilled and condenser
water
• Flow of chilled and condenser water
• Integrated Part Load Value (IPLV)
• kW/TR for 100% load but most equipment
operate between 50-75% of full load
• IPLV calculates kW/TR with partial loads
• Four points in cycle: 100%, 75%, 50%, 25%
32
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33. Assessment of Cooling Towers
Measured Parameters
• Wet b lb temperature of air
bulb temperat re
• Dry bulb temperature of air
• Cooling tower inlet water temperature
C li t i l t t t t
• Cooling tower outlet water temperature
• Exhaust air temperature
E h i
• Electrical readings of pump and fan
motors
• Water flow rate
• Air flow rate
33
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34. Central Plant metrics
• Chiller efficiency – kW/ton
• Cooling tower efficiency – kW/ton
• Condenser water pump efficiency – kW/ton
• Chilled water pump efficiency – kW/ton
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35. - Refrigeration cycle
- AC/Refrigeration Systems and
Components
-Type of refrigeration
- Assessment of refrigeration and AC
-Energy Efficiency Measures
- Energy Audit of HVAC System in
Commercial Building Utilities
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36. Energy Efficiency Measures
gy y
1. Optimize process heat exchange
2.
2 Maintain heat exchanger surfaces
3. Multi-staging systems
4. Matching capacity to system load
5. Capacity control of compressors
6. Multi-level refrigeration for plant needs
7. Chilled
7 Chill d water storage
t t
8. System design features
9. Optimize cooling tower
36
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37. Energy Efficiency Measures
1. Optimize Process Heat Exchange
p g
High compressor safety margins:
energy loss
gy
1. Proper sizing heat transfer areas of
heat exchangers and evaporators
g p
• Heat transfer coefficient on refrigerant side:
1400 – 2800 Watt/m2K
• Heat transfer area refrigerant side: >0.5 m2/TR
2. Optimum driving force (difference Te and
p g (
Tc): 1oC raise in Te = 3% power savings
37
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38. Energy Efficiency Measures
1. Optimize Process Heat Exchange
Evaporator Refrigeration Specific Power Increase
Temperature (0C) Capacity*(tons) Consumption (kW/TR) kW/TR (%)
5.0 67.58 0.81 -
0.0 56.07 0.94 16.0
-5.0 45.98 1.08 33.0
-10.0 37.20 1.25 54.0
-20.0 23.12 1.67 106.0
Condenser temperature 40◦C
Condensing Refrigeration Specific Power Increase
Temperature (0C)
p ) Capacity (tons)
p y( ) Consumption (kW /TR)
p ( ) kW/TR (%)
( )
26.7 31.5 1.17 -
35.0 21.4 1.27 8.5
40.0 20.0 1.41 20.5
*Reciprocating compressor using R-22 refrigerant. Evaporator temperature.-10◦ C
38
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39. Energy Efficiency Measures
1. Optimize Process Heat Exchange
p g
Selection of condensers
• O ti
Options:
• Air cooled condensers
• Air-cooled with water spray condensers
• Shell & tube condensers with water-cooling
• Water-cooled shell & tube condenser
• Lower discharge pressure
• Higher TR
g
• Lower power consumption
39
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40. Energy Efficiency Measures
2. Maintain Heat Exchanger Surfaces
g
• Poor maintenance = increased power
consumption
• Maintain condensers and evaporators
• S
Separation of lubricating oil and refrigerant
ti f l b i ti il d f i t
• Timely defrosting of coils
• Increased velocity of secondary coolant
• Maintain cooling towers
• 0 55◦C reduction in returning water from cooling
0.55
tower = 3.0 % reduced power
40
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41. Energy Efficiency Measures
2. Maintain Heat Exchanger Surfaces
Effect of poor maintenance on
compressor power consumption
Specific Increase
Te Tc Refrigeration Power kW/TR
Condition
(0C) (0C) Capacity* (TR) Consumption (%)
(kW/TR)
Normal 7.2 40.5 17.0 0.69 -
Dirty condenser
y 7.2 46.1 15.6 0.84 20.4
Dirty evaporator 1.7 40.5 13.8 0.82 18.3
Dirty condenser 1.7 46.1 12.7 0.96 38.7
and evaporator
41
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42. Energy Efficiency Measures
3. Multi-Staging Systems
g g y
• Suited for
• Low temp applications with high compression
• Wide temperature range
• Two types for all compressor types
• Compound
• Cascade
42
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43. Energy Efficiency Measures
3. Multi-Stage Systems
a. Compound
• Two low compression ratios = 1 high
• First stage compressor meets cooling load
• Second stage compressor meets load
evaporator and flash gas
• Single refrigerant
b.
b Cascade
• Preferred for -46 oC to -101oC
• Two systems with different refrigerants
43
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44. Energy Efficiency Measures
4. Matching Capacity to Load System
• Most applications have varying loads
• Consequence of part-load operation
q p p
• COP increases
• but lower efficiency
• Match refrigeration capacity to load
requires knowledge of
• Compressor performance
• Variations in ambient conditions
• Cooling load
44
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45. Energy Efficiency Measures
5. Capacity Control of Compressors
• Cylinder unloading, vanes, valves
• Reciprocating compressors: step-by-step through
cylinder unloading:
• Centrifugal compressors: continuous modulation
through vane control
• Screw compressors: sliding valves
• Speed control
p
• Reciprocating compressors: ensure
lubrication system is not affected
• Centrifugal compressors: >50% of capacity
45
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46. Energy Efficiency Measures
5. Capacity Control of Compressors
• Temperature monitoring
• Reciprocating compressors: return water (if
varying loads) water leaving chiller
loads),
(constant loads)
• Centrifugal compressors: outgoing water
temperature
• Screw compressors: outgoing water
temperature
• Part load applications: screw
compressors more efficient
46
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47. Energy Efficiency Measures
6. Multi-Level Refrigeration
Bank of compressors at central plant
• Monitor cooling and chiller load: 1 chiller full
load
l d more efficient than 2 chillers at part-load
ffi i t th hill t tl d
• Distribution system: individual chillers feed all
branch lines; Isolation valves; Valves to isolate
sections
• Load individual compressors to full capacity
before operating second compressor
• Provide smaller capacity chiller to meet peak
demands
47
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48. Energy Efficiency Measures
6. Multi Level Refrigeration
Multi-Level
Packaged units (instead of central plant)
• Diverse applications with wide temp range
and long distance
• Benefits: economical flexible and reliable
economical,
• Disadvantage: central plants use less power
Flow control
• Reduced flow
• Operation at normal flow with shut-off periods
48
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49. Energy Efficiency Measures
7. Chilled Water Storage
• Chilled water storage facility with
insulation
• Suited only if temp variations are
acceptable
• Economical because
• Chillers operate during low peak demand
hours: reduced peak demand charges
• Chillers operate at nighttime: reduced tariffs
and improved COP
49
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50. Energy Efficiency Measures
8. System Design Features
• FRP impellers film fills PVC drift eliminators
impellers, fills,
• Softened water for condensers
• Economic insulation thickness
• Roof coatings and false ceilings
• Energy efficient heat recovery devices
• Variable air volume systems
• Sun film application for heat reflection
• Optimizing lighting loads
50
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51. Energy Efficiency Measures
9. System Design Features
y g
- Selecting a cooling tower
- Fills
- Pumps and water distribution
- Fans and motors
51
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52. Energy Efficiency Measures
Selecting
S l ti a cooling tower
li t
Capacity
• Heat dissipation (kCal/hour)
• Circulated flow rate (m3/hr)
• Other factors
52
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53. Energy Efficiency Measures
Selecting a cooling tower
Range
• Range determined by process, not by system
Approach
• Closer to the wet bulb temperature
• Bigger size cooling tower
• More expensive
53
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54. Energy Efficiency Measures
Selecting a cooling tower
Heat Load
• Determined by process
• Required cooling is controlled by the
desired operating temperature
• High heat load = large size and cost
of cooling tower
54
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55. Energy Efficiency Measures
Selecting a cooling tower
Wet bulb temperature – considerations:
• Water i
W t is cooled to temp hi h th wet bulb
l dt t higher than t b lb
temp
• Conditions at tower site
• Not to exceed 5% of design wet bulb temp
• Is wet bulb temp specified as ambient (preferred)
or inlet
• Can tower deal with increased wet bulb temp
• Cold water to exchange heat
55
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56. Energy Efficiency Measures
Selecting a cooling tower
Relationship range, flow and heat load
• Range increases with increased
• Amount circulated water (flow)
• Heat load
• Causes of range increase
• Inlet water temperature increases
p
• Exit water temperature decreases
• Consequence = larger tower
q g
56
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57. Energy Efficiency Measures
Selecting a cooling tower
Relationship Approach and Wet bulb
temperature
• If approach stays the same (e.g. 4.45 oC)
• Higher wet bulb temperature (26.67 oC)
= more heat picked up (15.5 kCal/kg air)
= smaller tower needed
• Lower wet bulb temperature (21.11 oC)
= less heat picked up (12.1 kCal/kg air)
= larger tower needed
57
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58. Energy Efficiency Measures
Fill media
di
• Hot water distributed over fill media
and cools down through evaporation
• Fill media impacts electricity use
• Efficiently designed fill media reduces pumping
costs
• Fill media influences heat exchange: surface
area, duration of contact, turbulence
58
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59. Energy Efficiency Measures
Pumps and water distribution
p
• Pumps: see pumps session
• O ti i cooling water treatment
Optimize li t t t t
• Increase cycles of concentration (COC) by
cooling water treatment helps reduce make
up water
• Indirect electricity savings
y g
• Install drift eliminators
• Reduce drift loss from 0 02% to only 0 003 –
0.02% 0.003
0.001%
59
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60. Energy Efficiency Measures
Cooling Tower Fans
• Fans must overcome system
resistance, pressure loss: impacts
electricity use
• Fan efficiency depends on blade
profile
fil
• Replace metallic fans with FBR blades (20-
30% savings)
• Use blades with aerodynamic profile (85-92%
fan efficiency)
y)
60
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61. Benefits of Variable Flow
• Lowest Energy consumption
• Low Differential Pressure
• Easier Operation
• Reduced & Timely Maintenance
• Greatest Diversity
• Fewer or smaller chillers possible
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62. Why Variable Flow?
Why Variable Flow?
• Power varies with Cube of New Flow
Ratio.
- New Energy = New Flow / Old Flow (½), Cubed
(½)
= 1/8
- Most reliable operation.
Therefore, Energy Savings = 7/8 of the
original energy (less any losses from
new equipment)!
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63. Energy Efficiency Measures
Fill media
Comparing 3 fill media: film fill more
efficient
Splash Fill Film Fill Low Clog
Film Fill
Possible L/G Ratio 1.1 – 1.5 1.5 – 2.0 1.4 – 1.8
Effective Heat Exchange 30 – 45 150 m2/m3 85 - 100 m2/m3
Area m2/m3
Fill Height Required 5 – 10 m 1.2 – 1.5 m 1.5 – 1.8 m
Pumping Head 9 – 12 m 5–8m 6–9m
Requirement
Quantity of Air Required
Q tit f Ai R i d High
Hi h Much L
M h Low Low
L
63
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64. VPF system configurations
Manifolded
M if ld d pumps
– Redundancy
– Reduced energy
– VFD on all pumps
VFD ll
– Allows “overpumping”
for “Low ΔT
for Low ΔT
Syndrome”
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65. Keep it Simple
• Well designed control system is
Well designed control system is
mandatory.
• Mi i i
Minimize manual operation.
l i
• Develop clearly written operating
procedure and backup
failure mode.
• Continual training of
the operators.
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66. - Refrigeration cycle
- AC/R f i
AC/Refrigeration S t
ti Systems and
d
Components
-Type of refrigeration
- Assessment of refrigeration and AC
g
-Energy Efficiency Measures
-Energy Audit of HVAC System in
Commercial Building Utilities
Adel Mourtada 66

67. Typical Cooling Load Profile
yp g
Load in TR
Load in TR
300
250
200
150
Load in TR
Load in TR
100
50
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
67
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68. Energy Saving Possibilities
Energy Saving Possibilities
Reduce cooling Load
Adequate Regulation
Use VAV fans
Use VAV fans
Shift Cooling Demand To Reduce Required chiller
Off Peak Hours Capacity for meeting
the peak load
Reduce Maximum
Electrical Demand and Switch off Chillers during
Switch off Chillers during
hence corresponding
h d peak tariff period
Electrical Installation
Generate Hot Water up to Generate Pure water
60 ºC through through waste heat
waste heat recovery recovery from Chiller
from Chiller
from Chiller
68
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69. Interior Window Films
Interior Window Films
• If acceptable by
building
g
management,
y
window films may be
a useful option.
Choose film tailored
for climate.
Pay Back Period 2 years
69
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70. Programmable Thermostats or BMS
Programmable Thermostats or BMS
• They work when
They work when
you use them.
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71. VAV Fans Control
• Static Pressure Reset on VAV Systems.
– P id
Provides significant fan energy savings
i ifi t f i
since system is often at part load
– Reduces fan noise
“Variable air volume (VAV ) terminal units
shall be programmed to operate at the
minimum airflow when the zone
temperature is within the set
deadband.”
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72. Heat recovery from Chiller
y
Air‐
Air
Chiller Mode conditione
d Space
700 kW (200
TR) cooling
load
140 kW
140 kW
Electrical
Input
840 kW heat
840 kW heat
About 8‐12% of heat can be recovered in Chiller mode (i.e. 65‐100 kW
Rejected
heat) through desuperheater (Free of Cost ) through
~0.1 Carbon credit per hour CT/aircooled
~ 720 Carbon Credits/ Year (24hrs x 300 Days)
720 Carbon Credits/ Year (24hrs x 300 Days) condenser
d
72
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73. Partial Heat
Partial Heat Recovery
Recovery
Air cooled or
water cooled 50°C 55°C
Additional condenser
Desuperheater
p
refrigerant
fi t
fluid tank
Liquid Desuperheated Gas
Gas
Expansion
valve Compressors
Evaporator
Partial heat recovery
(Desuperheater) does not require
(Desuperheater) does not require
12°C
any additional electrical input. It
Chilled water 7°C recovers (8‐12%) of waste heat
73
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74. Hot Water Economics
ESTIMATES OF ANNUAL SAVINGS:
Hot water capacity : 10000 Lts/day
Diesel cost : 0.70$ per liter ; Diesel NCV :10100 Kcal/Liter ;
Boiler efficiency : 85%
Saving by Heat Recovery system over diesel fired boiler
S i b di l fi d b il
7000 US$/year
74
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75. Thermal Energy Storage System
Thermal Energy Storage System
CRISTOPIA STL phase change thermal energy storage
offers a unique solution to any of the following
energy management problems:
• Reduction of installed power
• Peak ‘shaving’ or ‘lopping’ of cyclic loads
• Optimization of electrical resources.
• Increase cooling output to meet higher demand
Increase cooling output to meet higher demand
without increasing existing plant capacity.
• Energy management (off‐peak electricity)
• Increase system reliability
• Back‐up function
• Protect ozone area by a limitation of CFC and HCFC
75
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76. Some Possibilities with STL
Discharge
kW of refrigeration
1000,0 Direct Production
Discharge 800,0 Charge
1200
k W o f re frig e ra tio n
Direct Production 600,0
1000
Charge 400,0
800
f
g
600 200,0
400 ,0
200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
0 Hours
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hours
Traditional Peak shaving with
Solution chiller switched
kW of re frigeration
1,200
Daily Consumption
1,000
Peak shaving
g 800
600 off during high
off during high
400
200
0
tariff period
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Discharge
1 000
k W o f refr era tio n
Hours
Direct Production Discharge
800
Charge 1000 Charge
ation
rig
600
kW of refrigera
800
400
600
200 400
0 200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0
Hours 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hours
Chiller switched off during high Pay Back Total storage during off
tariff period peak hours
period 4 years

77. ALMEE
77
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78. ALMEE
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79. Thank you for your attention
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80. Annex
- Instruments Required
- Cost Effectives Measures
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81. Instruments Required
Instruments Required
• Power Analyzer: Used for measuring electrical
parameters of motors such as kW, kVA, pf, V, A
and Hz
• Temperature Indicator & Probe
• Pressure Gauge: To measure operating
pressure and pressure drop in the system
• Stroboscope: To measure the speed of the
driven equipment and motor
• Ultra sonic flow meter or online flow meter
• Sling hygrometer or digital hygrometer
• A
Anemometer t
• In addition to the above calibrated online
instruments can be used
• PH meter
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82. Measurements & Observation
Energy consumption pattern of pumps and cooling
tower fans
Motor electrical parameters (kW, kVA, Pf, A, V, Hz,
THD) for pumps and cooling tower fans
Pump operating parameters to be
measured/monitored for each pump are: -
Discharge, - Head (suction & discharge) - Valve
position – Temperature - Load variation, Power
variation
parameters of pumps - Pumps operating hours and
operating schedule
Pressure drop in the system (between discharge
and user point)
Pressure drop and temperatures across the users
(heat exchangers, condensers, etc)
Cooling water flow rate to users - Pump /Motor
g p
speedd
Actual pressure at the user end
User area pressure of operation and requirement
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83. Exploration of Energy Conservation Possibilities
Water pumping and cooling tower
• Improvement of systems and drives
• Use of energy efficient pumps
• Correcting inaccuracies of the Pump sizing / Trimming of
impellers
• Use of high efficiency motors
• Integration of variable speed drives into pumps: The
integration of adjustable speed drives (VFD) into compressors
could lead to energy efficiency improvements, depending on
load characteristics
• High Performance Lubricants: The low temperature fluidity
and high temperature stability of high performance lubricants
can increase energy efficiency by reducing frictional losses
• Improvements in condenser performance
I t i d f
• Improvement in cooling tower performance
• Application potential for energy efficient fans for cooling tower
fans
• Measuring and tracking system performance
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84. Exploration of Energy Conservation Possibilities
p gy
• Measuring water use and energy consumption is
essential in determining whether changes i
i li d i i h h h in
maintenance practices or investment in
equipment could be cost effective
• In this case it is advised to monitor the water
flow rate and condenser parameters, cooling
tower parameters p
p periodically i.e. at least once
y
in a three months and energy consumption on
daily basis. This will help in identifying the -
- Deviations in water flow rates
- Heat duty of condenser and cooling towers
- Measures to up keep the performance
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85. Exploration of Energy Conservation Possibilities
p gy
System Effect Factors
• Equipment cannot perform at its optimum capacity if
fans, pumps, and blowers have poor inlet and outlet
conditions
• Correction of system effect factors (SEFs) can have
a significant effect on performance and energy
savings
• Elimination f
Eli i i of cavitation: Fl
i i Flow, pressure, andd
efficiency are reduced in pumps operating under
cavitation. Performance can be restored to
manufacturer s
manufacturer’s specifications through modifications.
This usually involves inlet alterations and may
involve elevation of a supply tank
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86. Exploration of Energy Conservation Possibilities
p gy
• Internal Running Clearances: The internal running
clearances b t
l between rotating and non-rotating
t ti d t ti
elements strongly influence the turbo machine's
ability to meet rated performance. Proper set-up
reduces the amount of leakage (
g (re-circulation) from
)
the discharge to the suction side of the impeller
• Reducing work load of pumping: Reducing of
obstructions in the suction / delivery pipes thereby
ypp y
reduction in frictional losses. This includes removal of
unnecessary valves of the system due to changes.
Even system and layout changes may help in this
including increased pipe diameter Replacement of
diameter.
components deteriorated due to wear and tear during
operation, modifications in piping system
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87. Sources:
- “Energy Equipments” UNEP/SIDA/Gerlap,
- “HVAC System Design”, Mark Hydeman, P.E., FASHRAE
Taylor Engineering, LLC.
- “Building Automatic System Bradley Chapman, DWEYER
Building System”
- “Solar Cooling”, Eco buildings, SARA.
- “Ventilation for buildings Energy performance of buildings Guidelines for
inspection of air-conditioning systems- EN 15240”, Intelligence Energy.
- “Energy Efficiency Guidelines”, Brahm Segal, Power Correction System.
- “Results of HVAC system monitoring of tertiary buildings in Italy”, M. Masoero,
C. Silvi, J. Toniolo , Politecnico di Torino, HarmonAC
- “Saving Energy Municipal Buildings and More”, Ben J Sliwinski Building
More” J.
Research Council School of Architecture, University of Illinois at Urbana-
Champaign. Kreider Curtis Rabl, Mac gGaw Hill.
- “Cleanrooms Energy Benchmarking”, Lawrence Berkley laboratory.
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