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Cooling Tower Water Recycling - Innovation Report Bloomberg London 103938/KW/010817 Revision 01

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Cooling Tower Water Recycling - Innovation Report

Bloomberg London 103938/KW/010817

Revision01

CoolingTowerWaterRecycling-InnovationReport103938/KW/010817Revision01Sweco 1 Bath Road Maidenhead Berkshire SL6 4AQ +44(0)[email protected]/our-offer/building-services

©Sweco2010ThisdocumentisaSwecoconfidentialdocument;itmaynotbereproduced,storedinaretrievalsystemortransmittedinanyformorbyanymeans,electronic,photocopying,recordingorotherwisedisclosedinwholeorinparttoanythirdpartywithoutourexpresspriorwrittenconsent.Itshouldbeusedbyyouandthepermitteddisclosesforthepurposeforwhichithasbeensubmittedandfornoother.RegisteredOffice:SwecoUKLimited,GroveHouse,MansionGateDrive,Leeds,LS74DN.CompanyRegistrationNo02888385

Issue Date Reason for Issue Prepared Checked Approved

01 Aug2017 Forinformation(BREEAM2014)

KW 08/17 TCF 08/17 AJD 08/17

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Contents

1. ExecutiveSummary..............................................................................................4

2. Introduction..........................................................................................................5

2.1 Overview...............................................................................................................5

2.2 TheProblem..........................................................................................................5

2.3 TheBenefits..........................................................................................................6

2.4 TheSolution..........................................................................................................6

3. TheDesign............................................................................................................7

3.1 RecyclingStrategy.................................................................................................7

4. TheBenefits..........................................................................................................9

5. WhyInnovative?.................................................................................................10

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01 Executive Summary

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1. Executive Summary ThisreportprovidesasummaryoftheCoolingTowerWaterRecyclingsolution,alsoisanabstractfromaBREEAMInnovationcreditapplicationfortheNorthBuildingoftheBloombergLondondevelopment.

ThedevelopmentprovidesamixofofficeandretailspaceintheCityofLondon.Locatedbetween theBankofEnglandandStPaul’sCathedral, the siteprovidesapproximately1million square feet of sustainable office space, two new public spaces featuringspeciallycommissionedworksofart,aretailarcadethatwillreinstateanancientRomantravelroute,andananticipatedculturalhubthatwillrestoretheTempleofMithrastoitsoriginalsite.

The application of cooling tower technologies result in a significant uplift in chillerefficiencies,throughtheprocessofrejectingheattoatmosphereviawater.Thisprocessenablesthisheatrejectiontooccuratornearwet-bulbtemperatures,insteadofatthehigher dry-bulb temperature in the case of air-cooled chillers, thus increasing overallchillerefficiency.

Despitethisobviousbenefit,thecoolingtowers’Achillesheelisthatlargequantitiesofwater are required for them to operate as designed. Inevitably, this water istraditionally sourced from potablewater sources, thereby increasing the demand for,anduseof,potablewater.

TheCoolingTowerWaterRecyclingsolutiondevelopedforBloombergLondonNorthemploys innovative techniques thatensureallbleedoffback-washwater thatwouldbeexpelledtodrainageinconventionalcoolingtowerdesigns,isinsteadrecycled.ThisisequivalenttoovertwoOlympic-sizeswimmingpoolsofpotablewaterforeachyearofoperation.

This innovativesolution isbelievedtobeunique forcommercialofficebuildings in theUK,andshouldprovidetheindustrywithastrongcasestudythatcanhelpdrivefuturedevelopment of these techniques. For these reasons, the Cooling Tower WaterRecycling solution developed for Bloomberg London North is considered to be aninnovationinsustainabilityandtheenvironmentaldesignofbuildings.

TheCoolingTowerWaterRecyclingsolutionforBloombergLondonwasawardedanAppliedInnovationcreditundertheBREEAM2014NewConstruction(non-domestic)scheme

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02 Introduction

2. Introduction Bloomberg London is a new development in the City of London comprising two high-gradespecificationbuildings(namelytheNorthandSouthBuildings),withretailunitsatgroundfloorlevel.Whencompleted,itwillprovideapproximately1,000,000ft2ofofficeand retail space and includes a new entrance to the London Underground at Bankstation.

Fig.1LocationoftheBloombergLondonDevelopment

2.1 Overview

BloombergLondonNorthBuildingutilisescoolingtowers,locatedatrooflevel,torejectwasteheatfromthemainchillerandcombinedcoolingheatingandpower(CCHP)planttoatmosphere.Thestandardapplicationofcoolingtowersmakesuseofmainswatertorejectthiswasteheat,withthebleedoffback-washfromthisprocesstypicallyexpelledthroughconventionaldrainage.

Inordertoleadthesustainableprinciplesoftheproject,thedesignteamforBloombergLondon recognised the need for achieving better and more efficient water usagesystems,inordertoreducetheconsumptionofpotablewater.Tothisend,anumberofinnovative solutions were developed and specified, including Cooling TowerWaterRecycling.

2.2 The Problem

Tacklingexcessivewaterconsumptionisapriorityforsustainabledevelopment.Potablewater is used typically for all sorts of processes beyond the obvious and necessaryrequirementforthoseconnectedtohumanconsumption. Processesatwork intypicalbuildingdesignsthatrequiretheuseofwaterincludethoseconnectedtosanitary(e.g.WCflushing),aswellasservicingHVACsystems.

Although cooling towers can result in a significant uplift in chiller efficiencies, thedisadvantage remains that they require largequantities ofwater in order for them to

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02 Introduction

operateasdesigned. Inevitably, thiswater is traditionallysourcedfrompotablewatersources, thereby increasing the demand for, and use of, potable water. Fordevelopment such as Bloomberg North Building, the quantities of potable water thatwouldbeneededtooperatethecoolingtowerswouldbesignificant.

Other risk elements to using large amounts of potable water formechanical systemsinclude the exacerbation of the challenges associated with drainage, and thecontributiontofloodingrisks.

Inlightoftheseconcerns,thedesignteamfeltitnecessarytodevelopsolutionswhich,throughtheirinnovativeapproach,wouldsignificantlyreducetheconsumptionofwater.

2.3 The Benefits

Despitethechallengesrelatedtoreducingwaterusage,thedesignteamrecognisedatan early stage the potential benefits such solutions could bring. In summary, thesebenefitsare:

• SignificantreductionintheconsumptionofpotablewaterforHVACservices

• Reductioninpotablewatercosts

• Reductionindrainagecosts

• Alleviationofpressuresplacedonageingdrainagesystems

• Thepreservationoffinitepotablewatersupplies

• Significantcontributiontoreducingtherisksassociatedwithflooding

Thepotentialbenefits identifiedbythedesignteamwereassessedtobeconsiderable.This acknowledgement led the team to explore how best these benefits could berealised. One of the solutions developed to this end was theRecycling of CoolingTowerWater.

2.4 The Solution

The solution developed addresses the significant water consumption associated withoperatingcoolingtowers.Theinnovativetechniquerecyclesallthebleedoffback-washwaste water from the cooling towers, to be used again in either the cooling towersthemselves,orinotherprocessessuchasWCflushing.

Thissolutionisinadditiontoothersignificantwatersavingmeasuresthatwillreusegreywatersourcedfromsystemssuchashand-washbasinsandcycleshowers.

ThisinnovativesolutionisbelievedtobethefirstofitskindinacommercialapplicationintheUK.

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03 The Design

3. The Design The Bloomberg North Building utilisescooling towers for heat rejectionpurposesfromthemainchillerandCCHPplant.

Cooling towers operate by utilising theeffectsofevaporativecooling.

Whilstthisresultsinsignificantincreasesin associated chiller efficiencies, thetowers themselves consume largequantitiesofwater.

A lot of this water is expelled toatmosphere, through its evaporation,and is often observable as a plume ofwatervapour.

There ishoweverasignificantquantityofwaterthat iswashed-back,tobeexpelledtodrainage in conventional designs. This bleed off is typically around 20% of the totalwater consumption of cooling towers. These significantly amounts of water wereidentifiedasbeingvaluableby-productsthatcouldberecycled.

3.1 Recycling Strategy

Theback-washwaterfromthecoolingtowerswillberecycledforuseinboththecoolingtowers themselves, as well as for storage alongside other grey water (which will beharnessedfromsourcessuchashandwashbasinsandcyclists’showers).

The anticipated approximate proportions of recycled cooling tower water will be asbelow.

Fig.2Recyclingofcoolingtowerwastewater

Fig.1Coolingtoweroperation

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03 The Design

GreywaterstorageislocatedcentrallyinbasementlevelB3andwillserveotherwaterconsumingprocessesthatdonotrequiretheuseofpotablewater,suchasWCflushing.

Itisanticipatedthatthesavingsinpotablewaterwillamountto:

• Over5,200m3peryearinpotablewaterconsumptionforthecoolingtowers,equivalenttoovertwoOlympic-sizeswimmingpools

• Over1,700m3peryearinpotablewaterconsumptionascontributionfortheflushingofWCs

ThesesignificantreductionsintheconsumptionofpotablewaterwillensureBloombergLondonNorthBuildingdeliverssustainabilitybenefitsthroughoutitsoperationallife.

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04 The Benefits

4. The Benefits The innovativenatureof theCoolingTowerWaterRecycling systemdeveloped forBloomberg London North Building will generate significant benefits across a range ofmeasures.Insummary,thesebenefitsare:

• SignificantreductionintheconsumptionofpotablewaterforHVACservices

• SignificantreductionintheconsumptionofpotablewaterforWCservices

• Reductioninpotablewatercosts

• Reductionindrainagecosts

• Significantcontributiontoreducingtherisksassociatedwithflooding

• Providingacasestudyfortheindustryasawholetoenablefurtherdevelopmentsinthis field,aswellasdemonstratetheapplicabilityandbenefits thatcanbeaccruedthroughthisdesign

Thevarietyofbenefitsisconsiderableinnatureandwillcontributetothedelivery,bothfor current operation as well as in the future, of tangible sustainability benefitsthroughoutthebuilding’slifespan.

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05 Why Innovative?

5. Why Innovative? ThedesignshouldbeconsideredInnovativeforthefollowingreasons:

• A technique that is believed to be the first of its kind anywhere in the UK in acommercialapplication.

• The innovative solution will reduce the water consumption of Bloomberg LondonNorthbuildingbyovertwoOlympic-sizedswimmingpools,eachandeveryyear.

• The application of this technologywill act as acase study for thewider industry,helpingtodriveinnovationsinthesustainableuseofwater.

• A significant contribution will be made to reducing the risks associated withdrainagecapacityandflooding.

InnovativeCoolingTower

WaterRecycling

BloombergNorthBuilding

TechniquethatisfirstofitskindintheUK P P P

ReducingwaterconsumptionbyovertwoOlympic-sizedswimmingpools,everyyear

P P P

Casestudyfortheindustry P P P

Reducingtherisksassociatedwithdrainageandflooding P P P

TheCoolingTowerWaterRecyclingsolutionforBloombergLondonshouldbeconsideredinnovative,andwasawardedanAppliedInnovationcreditunderBREEAM2014NewConstruction(non-domestic)scheme