achieving sustainability through integrated design

G.C.Modgil, Sterling India Consulting EngineersEmail: gcm@sterlingindia.in

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