G.C.Modgil, Sterling India Consulting Engineers Email: [email protected] ACHIEVING SUSTAINABILITY THROUGH INTEGRATED DESIGN
G.C.Modgil, Sterling India Consulting EngineersEmail: [email protected]
ACHIEVING SUSTAINABILITY THROUGH INTEGRATED DESIGN
NH8Hill
Agilent
Suzuki
Agilent Technologies Campus, Manesar
A corporate Hub for fragmented offices
1. A meaningful combination of aesthetics and sustainability in design.
2. Exemplary green building.
3. Example of innovative design and construction.
Let us understand the behavior of energy consumption in typical building:
Overall Energy usage pattern of Typical Building
Energy use of constituents towards HVAC system
50%
15%
25%
2%8%
Air conditioning Equipment Internal Lighting External Lighting Misc.
envelope34%
equipment18%
lighting15%
fresh air26%
occupant 7%
CHALLENGES FACED• Wide variation in day and night time loads • Varying Fresh Air Quantities• Very low occupancy and equipment load during
holidays• Round the clock plant operation • Very low occupancy and equipment load at night
The above challenges were overcome by building step-by-step efficiencies in systems.
HVAC DESIGN CONSIDERATIONS
• 300,000 ft2 five floor mixed use officebuilding
• 290,000 ft2 UFAD Office areas
• Server rooms and labs provided withprecision air handling units with chilledwater coils
HVAC SYSTEMS OVERVIEW
• 3X200 TR water cooled screw chillers
• 600 tons of connected load for UFAD systems
• Variable Volume Chilled Water Flow
• CT Fan Motor VFD
• Stratified Chilled water Storage
HVAC SYSTEMS OVERVIEW
• 36 Nos. 12,000 cfmAHUs• These air handling units provide ~ 60-65°F supply air
to UFAD supply plenum• Conventional system provided for reception, meeting
rooms and Cafeteria• Fan powered terminal units for perimeter zones
• Individual temp control with group of four diffusers
• Adjustable swirl floor diffusers
HVAC AIR SYSTEMS OVERVIEW
Three new systems were explored to maximize efficiency
1. Under Floor Air Distribution (UFAD)
2. Stratified chilled water storage
3. Energy Storage in Floor(concrete) Slab
NEW SYSTEMS EXPLORED FOR MAXIMUM EFFICIENCY
Figure 1
CONVENTIONAL OVERHEAD AIR CONDITIONING
Figure 2
UNDER FLOOR AIR DISTRIBUTION (UFAD)
Filter Coil Fan
OA
Relief
SA Terminal
Return
65 F
55 F
75 F75 F
78 F 75 F
Return Relief
Supply Plenum
Reci
rcul
ated
Bypa
ss
Recirculated
Supply
Fan Coil Filter
OA
UFAD CAD
StagnantZone Induction
ZoneUniform MixedZone
MixingZone
Uniform MixedZone
77 F
73 F
AIR SIDE DISTRIBUTION SYSTEM OPTIONS –CONVENTIONAL OVERHEAD MIXING OR UFAD
Chillers Primary Chilled Water Pumps Secondary Chilled Water PumpsCondenser water pumps CT Fans Air System Fans
ENERGY CONSUMPTION OF HVAC COMPONENTS
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
Constant Speed VAV UFAD
Annual AHU Power (kWh)
AHU FAN ENERGY CONSUMPTION OF CAD &UFAD
AHU ZONE PLAN CONSIDERED FOR CFD
One Floor Diffuser for each Work station
Swirl Diffuser
Raised floor
Dirt Tray
Modular components – Ease of space planning
Raised access floor panel dimensions: 610 mm X 610 mmUnderfloor plenum pedestal spacing: 610 mm C/C
Perimeter zone: 4–5 m deep from the external wall.
The depth of the raised floor: 400 to 500 mm
UFAD DESIGN CONSIDERATIONS
Determine return air configuration
UFAD DESIGN CONSIDERATIONS
Chilled water temperature between 6 to 9 oC
Chillers operate at full capacity
Chilled water stored at night time
STRATIFIED CHILLED WATER STORAGE SYSTEM
0
100
200
300
400
500
600
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Load (TR) Generation (TR)
Hrs
STORED ENERGY UTILISED DURING DAYTIME WHEN AMBIENT PEAKS
EXCESS ENERGY STORED DURING NIGHT AT LOW AMBIENT
STRATIFIED CHILLED WATER STORAGE SYSTEM
STRATIFIED CHILLED WATER STORAGE SYSTEM
STRATIFIED CHILLED WATER STORAGE SYSTEM
THREE ENERGY STORAGE MEDIUMS
• ICE• CHILLED WATER• CONCRETE
ENERGY SAVING BY NIGHT TIME ENERGY STORAGE IN CONCRETE SLAB
SPECIFIC HEAT AND DENSITY OF THESE ENERGY STORAGE MEDIUMS
Sp. Ht. Btu/lb Density lb/Cu.Ft. ICE 32 Deg F 0.487 57.5CHILLED WATER 0.999 62.32 CONCRETE 0.156 144
ENERGY SAVING BY NIGHT TIME ENERGY STORAGE IN CONCRETE SLAB
300,000 SQ. FT. AREA WITH 5” THICK SLAB HAS 125,000 CU. FT. OF CONCRETE
Holding capacity of Slab = 19,656,000 Btu at 7 Deg F ΔT= 1638 RTH
Days with less than 18 deg C temperature in a year = 139 Days
Thermal Storage in a year = 227,682 RTH
ENERGY SAVING BY NIGHT TIME ENERGY STORAGE IN CONCRETE SLAB