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Energy Efficiency in Existing Buildings
Air Conditioning Technologies for
Existing Buildings
ENERGY CONSERVATION
Easiest Way to Save Energy Do not Use EnergyWhen it is not required to use
Second method to Save Energy Use Energy to the min. extent required to use
ENERGY CONSERVATION
Use Energy to the min. extent required to use
• Human Behavior
•Technology Support
• Operational Practices
Buildings
16% Lighting
9% IT / electronics
10% Water heating
25% Other
40%
32%
28%
Transportation
Industry
100%
40% HVAC
ENERGY CONSUMPTIONEnergy Pockets
Energy costLife cycle cost analysisChange of energy source
EnvironmentCO2 emissionsRenewable energyZero-net energy buildings
RegulationsEPBD/ASHRAE 189 Energy-using product codesEnergy certificates/LabelingTax incentives
EfficiencyVFD / inverterThermodynamic heatingHeat recovery systems
RefrigerantsHCFC Phase-outLow GWP & natural refrigerants
GLOBAL TRENDS
5
System approach
6
HVAC SYSTEM
Example : Hotel Space
HVAC System Efficiency
Asean China India Australasia
Plant Efficiency near Peak Loads Plant Efficiency at Part Loads
8
HVAC System Efficiency
High Variability
9
HVAC System Efficiency
Solution ?Blue prints
CONSTRUCTION APPROACHHVAC System
Load Estimates
OccupancyLightingEquipmentSolar Buildings / Applications Equipment Choices
Boiler Chiller
Design System / Equipment Selections
System – Heating , Cooling
Operating Cost
Energy Saving
First cost
Capex / Opex
Plant Room : 500TRCapex : $600KOpex : $1.0m
11
Can we consider a system to be
• Larger equipment with each individualequipments as its components ?
If Yes …
• System has its own Operating &Efficiency Curve
• System Efficiency depends on EquipmentEfficiencies , but interdependent on other equipments
System Level Solutions
12
REAL LIFE ENERGYOperational Challenges
Buildings Rarely Operate atFull Loads
Building Cooling Load(Tons)
Time in a Day
1500
db
wb
Daily TemperatureProf ile
Cooling Load Varies Over Time
Building Load Varies Continuously
Design Vs Actual loadDeviations
Sys tem Tonnage Profi le
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
800.00
0:00
1:00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:0
0
11:0
0
12:0
0
13:0
0
14:0
0
15:0
0
16:0
0
17:0
0
18:0
0
19:0
0
20:0
0
21:0
0
22:0
0
23:0
0
Time
Cool
ing
Tonn
age
(RT)
19-Ma y-09 20-May -09 21-Ma y-09 22-May -09 23-Ma y-09 24-May -09 25-Ma y-09 26-May -09 27-Ma y-09 28-May -09 29-Ma y-09
30-Ma y-09 31-May -09 01-J un-09
Pea k: 600RT
Off Pea k: 400RT
Prediction of Load Pattern Changing Weather Conditions
Chillers Pumps Coolingtowers
Compatibility within Equipments
13
HVAC COMPONENTSLoad & Weather dependent Operating Curves
• Efficiency Changes with operating conditions• Performance depends on External System factors also
14
System Waste
REAL LIFE ENERGY
Pump Over Sizing
Pump over- sizing causes the pump to operate to the far left of its best efficiency point (BEP)
Over sizing is the single biggest culprit of pumps wasting energy
Unnecessary Piping Bends
Valve LeakagesCooler Valves: 20% Leak à
Reduced Capacity by 20% à Increase Chiller running Hrs by 20%
Condenser Valves: 20% Leak à Reduced Capacity by 5% + 8% increased consumptionà Increase Chiller running Hrs.
Cooling Tower Valves: 20% Leak à Increase CDEWT à + need to run more towersà increase power consumption
Cooling Tower Spacing
Load Vs Chiller eff. Mismatch
Major operation
loadings
Tube Fouling
15
ENERGY SOLUTION
Integrated System
• Changing the System Characteristics accordingto Operating Conditions
• Building Loads• Ambient Conditions• System Variations
• Dynamic Optimization of System operating point to Ensure lowest Energy Consumption
• Waste Heat Recovery
• Dynamic System Balancing to Eliminate Waste
16
ENERGY SOLUTIONExample :Plant Room Optimization
17
GREEN MAINTENANCEExample : Tube Fouling
Fouled Tubes Cleaned Tubes
11.5%Power
RequirementsCondTemp
110 F
105 F
100 F
18
GREEN MAINTENANCE
26Apr’13 04Jun’13 08Aug’13
Example : Auto Tube Cleaning
THANK YOU