Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
Managing energy by design with low energy comfort systems
by Punit H Desai, Green Initiatives, Infosys Ltd
Energy consumption distribution
Air conditioning40%
Lighting / Raw power15%
UPS/Computing40%
Misc.(5%)
3
Managing energy with low energy comfort systems
4
Managing HVAC energy
5
Reduce Air-conditioning load by design
Goal : Limit external heat gain to less than 1 watt/sqft & 1 TR should cool min 550 sqft
Building shape and orientation, Roof Insulation (Over deck roof insulation) Reflective roofs Wall Insulation - Double brick wall construction with insulation and air cavity Window wall ratio Heat avoiding Glazing (Double glazed windows with argon filling) Efficient lighting and computing devices
6
Do efficient design and select efficient technologies
Goal : HVAC system ikw/tr < 0.6 for plant room
Innovative cooling technologies – Radiant cooling Radiant cooling separates out latent and sensible loads Uses 16 deg C chilled water for sensible cooling Takes benefit of lower ambient humidity whenever avaialble
Low pressure drop design for piping and equipments Low pressure drop design for AHUs and ducting Automation for smart operation High efficiency chillers, pumps and cooling towers
7
Building Orientation – Minimum surface area and windows on E & W
West East
North
South
Building envelope
• Efficient walls: Insulation for the walls minimizes heat gains into the building through walls. The exterior walls are cavity brick walls with insulation that let in only 1/5th of the heat into the building compared to a conventional 9” brick wall.
Heat transfer co-efficient:
U – 0.4 btu/hr ft2 F ( Insulation – XPS – R5 with 25mm), Total R-14
Double brick cavity wall with insulation and air gap
100mm
200
50
75
Interior Exterior
Building envelope
• Efficient roof: Insulation for the roof minimizes heat gains into the building through the roof. The roof for Mysore SDB-5 are insulated over deck and let in only 1/8th of the heat into the building compared to a conventional RCC roof.
Heat transfer co-efficient:
U – 0.35 ( Insulation – XPS – 75 mm, no air gap), Total R-16
Insulation above the RCC layer and sloping
Building Envelope: High Performance glazing
35 0C24 0C
900 W
540 W360 W
55 W
35 0C
24 0C
900 W
90 W
810 W
12 W
Single glass Spectrally selective double wall glass with Argon filling
Single Glass
U = 5
Double pane glass with argon filling
U = 1.2 , SHGC =0.2
11
Window wall ratio, differs on all sides
Double brick wall with insulation
12
Radiant cooling technology – chilled water @ 16 deg C embedded in slab
13
Managing Lighting energy
14
Strategy 1 : Maximize day lighting, use as much natural light as possible
Goal : 90% of the area should be day lit
Limit floor depth to allow maximum day light coverage (20 m) Split the window into view pane and day light pane Use suitable glass for view pane and day light pane (Daylight to have high VLT) Use internal light shelves for effective day light penetration Use shading to cut glare
15
Day light pane
View pane
External shading
Smart glazing
Internal Light shelf
Building envelope
• Building simulation used to design the shading devices• Minimize heat gain• Minimize glare from sunlight• Maximize daylight in the spaces
17
Strategy 2 :Design efficient system
Goal : Total connected lighting load should be less than 0.5 watt/sqft
Use lighting simulation programs to optimize lighting fixtures (gives 30% reduction) Use high efficiency lights and fixtures (T5) Use LED in common areas, stair case, rest rooms Use occupancy sensors in meeting rooms, conf rooms, rest room
19
Managing Computing energy and plug loads
20
Managing IT and plug loads
Reduced number of plugs per workstation Segregated UPS plug points from raw power plug points Energy efficient IT procurement Selection of high efficiency and modular UPS (greater than 94% efficiency) Developed software to switch off computers automatically based on employee
prescribed time (Terminator application) Employee awareness programs
Managing energy by operations
22
Benefit to Infosys
In 2007-08
• Average for software buildings (incl. lights, AC, computers, etc.)
Building energy: 200-240 kWh/sqm per year
• Average for software buildings across campuses
Lighting design: 1.2-1.4 W/sqft
• Average installed cooling capacity across campuses
AC design: 300-350 sqft per TR
• Total electrical load for software buildings including chiller plant
Electrical design: 6.5 W/sqft
23
In 2011-12
• Average for software buildings (incl. lights, AC, computers, etc.)
Building energy: 90 kWh/sqm per year
• Average for software buildings across campuses
Lighting design: 0.5 W/sqft
• Average installed cooling capacity across campuses
AC design: 550-650 sqft per TR
• Total electrical load for software buildings including chiller plant
Electrical design: 3.5 W/sqft
24
~55% lower
~60% lower
~36% lower
~46% lower
Thank you
• www.infosys.com
• The contents of this document are proprietary and confidential to Infosys Limited andmay not be disclosed in whole or in part at any time, to any third party without the priorwritten consent of Infosys Limited.
• © 2011 Infosys Limited. All rights reserved. Copyright in the whole and any part of thisdocument belongs to Infosys Limited. This work may not be used, sold, transferred,adapted, abridged, copied or reproduced in whole or in part, in any manner or form, or inany media, without the prior written consent of Infosys Limited.
Punit H. DesaiSenior Manager – Green [email protected]+91 7829918740