energy efficiency in buildings - dsm -...
TRANSCRIPT
ENERGY EFFICIENCY IN
BUILDINGS
JYOTIRMAY MATHUR
PROFESSOR, MECHANICAL ENGINEERING DEPARTMENT
AND
CENTRE FOR ENERGY AND ENVIRONMENT
MALAVIYA NATIONAL INSTITUTE OF TECHNOLOGY JAIPUR
BUILDING SECTOR OF INDIA
Source - Growth of Indian building sector CWF 2010
Energy consumption Growth
Source : Energy statistics 2013
2005 2030
8%
10%
5%
8%
Built up area
50 billion sq ft
Built up area
25 billion sq ft
Built up area
100 billion sq ft
CONSTRUCTION SECTOR IN INDIA
IMPORTANCE OF HVAC/BUILDINGS
WHERE ARE WE AND HOW MUCH IS
SCOPE FOR IMPROVEMENT?
WAY Towards Net Zero Energy Buildings
“Net- Zero” Energy Building
Zero Net Site Energy Use
The amount of energy provided by on-site renewable energy sources is
equal to the amount of energy used by the building.
Net Off-site Zero Energy Use
100% of the energy purchased by a building comes from renewable
energy sources, even if the energy is generated off the site.
Net Zero Cost
The cost of purchasing energy is balanced by income from sales of
electricity to the grid of electricity generated on-site.
Net Zero Energy Emissions
The carbon emissions generated from on-site or off-site fossil fuel use are
balanced by the amount of on-site renewable energy production.
Paradigm Shift
S.N
o
Description Earlier Now Aiming
1 Energy Use 20 W/sqft 8 W/sqft 4 W/sqft
2 AC Load 200sft/TR 400 sft/TR 800 sft/TR
WHERE DO WE START………….
A Case study
A Typical BuildingProject Specification
Project Type: Hotel/Commercial
Number of floors: G+8
Window to Wall Ratio: 55%
Wall U value: 0.33 Btu/h sqft F
(Brick wall construction)
Roof U value: 0.34 Btu/h sqft F
(Concrete roof without insulation)
Cooling Load: 2000TR (150sqft/TR)
Glass: 6 mm single glazed
Glass SC: 0.93
Glass U Value: 1.0 Btu/h sqft F
Co
mm
on
Pra
ctic
e
Contribution by Envelope
Contribution by Internal
LoadsContribution by Fresh Air
Loads
Contribution of façade in energy consumptionEnergy Intense facades of a typical building
Contribution by Façade
Contribution by Roof
Wall Contribution to gains
Window Contribution to gains
87%
13%
47%
25%
28%
89%
11%
87%
13%
Co
mm
on
Pra
ctic
e
N
S
EW
Optimizing Orientation (2%)
Annual
Ener
gy C
onsu
mpti
on (
mW
h)
Ori
enta
tion
Opti
miz
ati
on
Parameter Typical
Building
Last
Improvement
Current
Improvement
Elec. Consumption
(MWh)
9,120 9,120 9,020
Cooling Load (TR) 2000 2000 1986
Carbon Emissions
(Tons)
7,843 7,843 7,755
E
S
W
N
9010
9035
9060
9085
9110
9135
0 225 135 90 315 90 45 270
Optimizing Window Wall Ratio (15%)
Annual
Ener
gy C
onsu
mpti
on (
mW
h)
7000
7500
8000
8500
9000
9500
55 50 40 35 25 20
Win
dow
to W
all
Rati
o
Parameter Typical
Building
Last
Improvement
Current
Improvement
Elec. Consumption
(MWh)
9,120 9,020 7,590
Cooling Load (TR) 2,000 1,986 1,400
Carbon Emissions
(Tons)
7,843 7,755 6,527
Window to Wall ratio (%)
Optimizing shading devices (7%)
Annual
Ener
gy C
onsu
mpti
on (
mW
h)
7000
7100
7200
7300
7400
7500
7600
7700
Base Shade 0.5ft Shade 1ft Shade 1.5ft Shade 2 ft
Sh
adin
g D
evic
es
Parameter Typical
Building
Last
Improvement
Current
Improvement
Elec. Consumption
(MWh)
9,120 7,590 7,099
Cooling Load (TR) 2,000 1,400 1,338
Carbon Emissions
(Tons)
7,843 6,527 6,105
6600
6650
6700
6750
6800
6850
6900
6950
7000
7050
7100
Base 1 2 3 4 5 6
Single Glazed Unit Double Glazed Unit Double Glazed
Unit + E coating
Annual
Ener
gy C
onsu
mpti
on (
mW
h)
Gla
ss S
elec
tion
Optimizing glass selection (6%)
Parameter Typical
Building
Last
Improvement
Current
Improvement
Elec. Consumption
(MWh)
9,120 7,099 6,687
Cooling Load (TR) 2,000 1,338 1,200
Carbon Emissions
(Tons)
7,843 6,105 5,750
5600
5800
6000
6200
6400
6600
6800
R3 R9 R13 R19 R24
Optimizing Wall assembly (3%)•R 3 (U Value=0.33 Btu/h sqft F) –
Brick Wall
•R 9 (U Value=0.11Btu/h sqft F) –
AAC Wall
•R 13 (U Value=0.07Btu/h sqft F) –
Brick Wall + 2inch XPS insulation
•R 19 (U Value=0.05Btu/h sqft F) –
AAC Wall + 2inch XPS insulation
•R 24 (U Value=0.04Btu/h sqft F) –
AAC Wall + 2.5 inch PUF insulation
An
nu
al E
nerg
y C
onsu
mp
tio
n
(mW
h)
Brick
Wall
AAC
Wall Brick +
XPS AAC +
XPSAAC +
PUF
Wa
ll S
elec
tion Parameter Typical
Building
Last
Improvement
Current
Improvement
Elec. Consumption
(MWh)
9,120 6,687 5,975
Cooling Load (TR) 2,000 1,200 1,100
Carbon Emissions
(Tons)
7,843 5,750 5,138
Cumulative Reduction
9120• Basecase in Composite climate
9020• Right Orientation
7590• Window Wall Ratio 20%
7099• Shading devices 2ft
6687• Proper selection of glass
5975• Wall construction
2000
1986
1400
1338
1200
1100
Annual Energy Consumption
(MWh)
Tonnage Reduction
(TR)
34
% S
avin
gs
45%
Sav
ing
34
% S
avin
g
CO2 emissions
(Tons)
7843
7755
6527
6105
5750
5138
Base Building
Improved Building5975 1100 5138
9120 2000 7843
PROJECTIONS OF ENERGY SAVINGS FOR HOTEL
SECTOR OF JAIPUR CITY
107.8
84.6
67.8
0
20
40
60
80
100
120
Existing ECBC Advanced
En
erg
y c
on
su
mp
tio
n (
GW
h/y
ea
r)
Energy savings
ECBC - 23.2 GWh/year
Adv. - 40.0 GWh/year
VIVEKANAND LECTURE THEATRE
COMPLEX
Passive: Self shading footprint,
window sizing, recessed windows,
courtyard
AAC Blocks
PVC frame Double Glazed Window
Daylight integration
• All-variable, water cooled HVAC
• Heat recovery units
• 100kWp SPV plant on roof
• Fan+AC with higher temperature
setting
• AC capacity reduced to less than
50%
TECHNOLOGY
TYPES OF HVAC SYSTEMS
APPLICATION TYPE OF SYSTEM Typical AC Load
Residential Unitary
VRF
Upto 20 TR
Mid Size Buildings VRF
Ductable Split Units
Package Units
30-100 TR
Large Buildings Central Plant >100 TR
Prefer Water cooled systems by using recycled water from
Sewage Treatment Plants
CCHP SYSTEMS
CHILLED BEAM
Chilled Beams/ Chilled Ceilings
• Convection process is the transfer of heat energy in a water or air medium. Chilled
ceiling, Active/Passive chilled beams working on the principle of convection
currents. Mixed type air- distribution system.
UFAD
Conventional Overhead VAV Air Distribution System
• Mixing Type Air Distribution System, Entire volume of air in occupied space at the desired set point temperature.
Under Floor Air Distribution (UFAD)
• Stratified Type Air Distribution System, Occupied space at the desired set point temperature.
Reduce Energy Use
• Under floor plenum is the primary air distribution route.
• Under floor HVAC systems use less ductwork than Overhead systems
• Primary fan pressure reduced.
• Substantial energy savings on primary fan power possible, however, this may be offset by fan powered diffusers used in perimeter areas
Combination Systems
Passive Beams
Floor Diffusers
Passive Chilled Beam
PROVIDING COOLING ON DEMAND….
• Demand based ventilation linked to IAQ &CO2 sensors.
• Lighting on demand through Day-light &occupancy sensors.
• Cool air through demand based onTemperature sensors.
• Chilled Water flow on demand throughvariable flow pumping system.
• VFD on AHU, Cooling Towers
DESICCANT COOLING AND HEAT
RECOVERY WHEELS
• Recovery of cooling effect going waste in exhaust air
• Pre-cooling and dehumidification of incoming air
• Recovers upto 70-80% energy in high occupancy applications
• Heat Pipes/Heat Recovery Wheels/Dessicants
• Geo thermal heat exchange technology installed for heat
rejection from Air-conditioning system
INNOVATIVE TECHNOLOGIES
Geo Thermal
Radiant Cooling System Studies
Energy Saving Results
0
50
100
150
200
250
300
350
400
VAV RC+DOAS
MW
h
Copmarison of RC+DOAS and VAV
Chiller Fan
Primary Pump Condenser Pump
28%
Conv Case RAD+FCU RAD+DOAS
Pump 414.2 1,452.7 1,172.0
Fan 6,213.4 3,161.8 1,847.3
Chiller 14,083.7 12,476.3 11,257.7
0.0
5,000.0
10,000.0
15,000.0
20,000.0
25,000.0
kW
h
Energy Consumption Comparison of All Cases
17.5%
SAVING30%
SAVING
Tech Mahindra Radiant System Annual Energy Consumption Of All Three Cases
8
72
17
30 0 0 00 1
15
3230
14
7
1
0
10
20
30
40
50
60
70
80
295.5-296 296-296.5 296.5-297 297-297.5 297.5-298 298-298.5 298.5-299 299-299.5
Per
cen
tage,
%
Temperature Range, (K)
Average Air Temperature Distribution
Radiant
Conventional
April 09, 2013
Mean Air Temperature of Zone
Tech Mahindra RadiantMean Air Temperature of Zone
37
IN HOUSE STUDY (RADIANT CUBICAL)
Figure: (a) Experimental setup of Radiant Cubicle, (b) Meshed drawing of Room to be simulated, (c) Mesh
representation of cubicle
Experimental Setup DetailsDimension of Cubicle: 4.5*3*4 feet (HxWxL)Material of Cubicle: AluminiumMaterial of Pipe: Copper (ID – 4inch)
Meshing DetailsCell Size: 10,33,186Mesh Type: Hexahedral
ADAPTIVE THERMAL COMFORT
• Set point is not fixed at 22 degree for all
• Human nature is adoptive to climatic conditions
• Set point should vary with season and time of day
DATA CENTERS NEED SEPARATE TREATMENT
• Consume 10 to 100 times more energy per
square foot than a typical office building.
• Under floor supply of air
• Cold & Hot Aisles
• Raising of Temperatures
MODIFIED LAYOUT OF DATA CENTER
10-12% energy saving
IMPORTANT……………………
DISTRICT ENERGY
SYSTEMS
DRIVERS FOR ENERGY
EFFICIENCY
Green building movement
ECBC
Star labelling
Benchmarking
Energy efficiency awards
Energy Pricing
GREEN BUILDING
MOVEMENT
Rapid growth in green footprint
Growth of professionals
Growth of market
Public awareness: creation of green mindset
ENERGY CONSERVATION
BUILDING CODE
Launched in 2007
State subject for implementation
Scope: commercial buildings
Limit lowered from 500kW to 100kW in 2011
PROGRESS: ECBC
Capacity building programs
Master trainer program
Learning material: User Guide, Training packages
Government system gearing up: Opening of ECBC Cells in
few states
ISSUES AND WAY
FORWARD FOR ECBC
Third party certification process needed
Multi level training/curriculum
More easily accessible testing facilities needed
Compliance tool: Continuous and transparent work
More Pilots/Demo buildings with documentation
State subject: one up tendency of states
Over-expectation: extra FAR
Future versions: Periodic, Simplification, Transparent
FUTURE NEEDS AND
DIRECTIONS
BIPV: Load profile control
Net metering: lack of interest of utilities
Energy storage: can be game changer
Differential Tariff
Net Zero: Should India pursue?
Energy efficiency to be embedded in town planning
