cibse guide l: sustainability meets ashrae green …cibseashrae.org/presentations/hywel1107.pdfcibse...

14 November 2007

CIBSE Guide L: Sustainabilitymeets

ASHRAE Green Guide

Presented by Hywel Davies

CIBSE Technical Director

Based on material prepared by

Dave Cheshire, Faber Maunsell

14 November 2007 CIBSE Guide L meets ASHRAE Green Guide

CIBSE Guide L:Sustainability


ASHRAEGreenGuide


Defining SustainableDevelopment


Definingsustainability

• “providing for theneeds of thepresent withoutdetracting from theability to fulfill theneeds of the future”

GreenGuide


Definingsustainability -

GreenGuide• Minimising natural resource

consumption• Renewable energy resources to

achieve net zero energyconsumption

• Minimising emissions, includingindoor air quality, greenhousegases

• Minimising discharge of solidwaste and liquid effluents

• Minimal negative impacts on siteecosystems

• Maximise quality of indoorenvironment

IAQ

Energy & water

Renewables


Drivers forsustainability

cf ‘Owners ProjectRequirements’ in

GreenGuide

CIBSE IntroductionFigure 6


Planning drivers

• PPS on Planning and Climate Change• Further Alterations to the London Plan

(including proposed 20% renewablestarget)

• SPG on Sustainable Design andConstruction

• Ensuring Part L compliance pre-planning

= more involvement early on


ASHRAE GreenGuide – Overview

Content: Three Basic Sections

Basics(Chapters 1 – 2)

Design Process(Chapters 3– 16)

Post Design(Chapter 18)


ASHRAE Green GuideThe Design Process

• Chapter 3: Commissioning (Cx)– Why is this the 3rd chapter in the book?– Phases of Commissioning

Preliminary

Design Construction

Acceptance

ContinuousCx


Commissioning

• “…a comprehensive commissioning process thatstarts during pre-design …”

• The main role at pre-design is to developcomprehensive Owners Project Requirements

• This is similar to the role of the sustainabilitychampion

• Also, look at commissionability of the systems atdesign phase


LEED and BREEAM

• Provides a chapter onLEED guidance forHVAC engineers

• BREEAM not aseparate chapter inCIBSE - referencedwherever relevant


GreenGuide targets

• Achieve a level of energy use at least 50% lower than theDOE-compiled average levels for the same building type andregion, both projected an in actual operation;

• Provide at least 15% of the building’s annual energy use (inoperation) from renewable sources

• Achieve per capita water usage 40% lower than thedocumented average for building type and region

• Recycle products and post-occupancy evaluation• (NOTE: Still deals in energy rather than CO2)


Setting targets


Conceptualbuilding modelling

• GreenGuideadvocates the useof ‘conceptualbuilding modelling,and optionsappraisal


0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

Notional (Part L) Proposed (Part L) Total carbon dioxide

emissions

Renewables target

Carb

on

dio

xid

e e

mis

sio

ns (

kg

CO

2y

r)

Small power

DHW

Lighting

Ventilation

Cooling

Heating

28%10%

Part L Planning

Energy strategy


Shiny new toys


Adapting to climatechange

• GreenGuide proposes nightpre-cooling as a strategy

• Guide L shows Urban HeatIsland effect problems in cities

• Central London 5–6 °Cwarmer than rural areas.

• Difficult to dissipate heat atnight


Living roofs

• Vegetation absorbs less heatthat bare roofs

• Transpiration of waterprovides cooling andhumidifying effect

• Helps heat island andreduces amount of coolingrequired

• Can be used with PV• (See CIBSE Green Roofs KS)


Adapting to climatechange

Predicted impacts of climatechange include:

• general increases intemperatures, including milderwinters and rising summertemperatures

• enhanced urban heat island• wetter winters, more intense

rainfall• dryer summers• higher daily mean winter wind

speeds

Climate Change Scenarios for the UK,UKCIP02 (2002)


Urban heat islandeffect

• In central London theurban heat islandeffect can currentlylead to temperature5–6 °C warmer thantemperatures in ruralareas outside London.

• Difficult to dissipateheat at night


Pollution -Refrigerants


User controls

BORDASS W., LEAMAN A and BUNN R, Controls for End Users: a guide for good design andimplementation, Building Controls Industry Association (BCIA), March 2007 ISBN 0 86022 622


Fees

• Less kit = lower fees!• GreenGuide: reducing

loads should be avaluable service

• 7% of fee forconceptual design – is itenough?


Cost of beinggreen?

• GreenGuideargues that it iscost neutral

• Productivity andoperating costsshould be off-set


Lessons learnt

Differences:• Commissioning considered at start• Adapting to climate change• Load reduction or shiny toys?• Wide topic: ‘sustainability’ –

should we focus more?• All greenhouse gases matter• CO2 emissions important


Lessons learnt

Similarities:• Increase role of engineers• Early involvement (load

reduction etc.)• Similar definition of

sustainability• Advocate / champion for

sustainability• Set targets at the start of

the project

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