The Windcatcher principle, of encapsulating any...

The "Windcatcher" principle, of encapsulating any prevailing wind, originated some 2,000 years ago inthe Middle East, where "Wind Towers" were often a common sight. The modern MonodraughtWindcatcher is an extension of this principle but is also a development of the highly successfulMonodraught Vertical Balanced-flue system invented in 1965 (William Stranks, Patent No.1063909).This unique Monodraught Balanced-flue arrangement of entraining air into the boiler room forcombustion ventilation from roof level has now been utilised by almost all leading companies in the UKto provide optimum ventilation for any boiler house configuration. The Monodraught Windcatcher naturalventilation system, which evolved from the Balanced-flue system, was launched in 1995.

Harnessing our Natural Resources

Page 3 Monodraught Company Profile

Page 4 Windcatcher Natural Ventilation systems

Page 5 Windcatcher – the driving force

Page 6 Fire Dampers & Security/Noise Transmission

Page 7 Night-Time Cooling

Page 8 Designing a Natural Ventilation system

Page 9 Windows and Door Openings

Page 10 BRE Test Results

Page 11 BRE Test Results

Page 12 Controls

Page 13 Summer and Winter Operation

Page 14 Air to Air Heat Recovery system

Page 15 Installation

Page 16 Multi Floor Operation

Page 17 Research and Development

Page 18 Monodraught Bespoke systems

Page 19 Monodraught SunCatchers

Contents ...from 2000 years experience.

Monodraught

2 Monodraught

The Monodraught Vertical Balanced-flue system, the forerunner of theMonodraught Windcatcher system, takes ventilation air from the top of thechimney – the same pressure zone as the flue outlet – to create the correct‘balanced’ conditions for optimum boiler efficiency.

A single composite unit – available in any size, for single or modular boilers –meets all requirements for a highly cost-effective and efficient combustion air,ventilation and flueing system. The effect of downdraught is eliminated,regardless of outside wind conditions.

A separate brochure is available on the Monodraught Balanced-flue system.

Company Profile

The CompanyMonodraught Ltd was foundednearly 30 years ago by the presentChairman and Managing Director,Terry Payne. Since then thecompany has specialised in thedevelopment of natural ventilationsystems and low energy conceptsfor the building environment.

Unlimited DesignPotentialA significant feature of theMonodraught product rangecontinues to be the high level ofarchitectural and design empathyachieved through design flexibility.

This enables designs to be visuallyappealing whilst achieving anefficient and practical contribution tothe harnessing of our naturalresources. There is virtually no limitto the design potential ofMonodraught systems, which aremanufactured to a standard rangebut bespoke features can always beincorporated. Systems are manufact-ured to any BS or RAL colour.

MaintenanceA particular feature of Monodraughtsystems is the emphasis on lowmaintenance. Manufactured in GRP,all Monodraught systems are coveredby a unique 25 year guarantee.Dampers and controls fitted into the

Monodraught

Left: Windcatchers installed at the BuddhistTemple and Chanting House at Taplow Court.

Monodraught 3

systems will be covered by thenormal manufacturer's warranty.

Looking AheadBy the end of the year 2003,Monodraught will have suppliedand installed more than 15,000Windcatcher, SunPipe andSunCatcher systems on School,College and University Projects, aswell as Offices, SecureEstablishments, Leisure Projectsand Health Centres. Monodraughtare committed to establishingrenewable energy concepts thatreplace the need for airconditioning during summermonths and the need for electriclighting during daylight hours.

Specially designed Windcatchersinstalled at Addey and StanhopeSchool, Deptford, London. TheWindcatcher design perfectlycompliments the architecture ofthis new build structure andincorporates special acousticlining and acoustic pods.

Plymouth University where 7 No. 1000mmdiameter Windcatchers were installed.

W.H. SmithHeadquarters,SwindonMr Geoff PetersConsulting Engineers:Applied Energy, Cobham, Surrey

These award winning offices,

built in 1985, were designed as

low energy structures, without air

conditioning or mechanical

ventilation. Since then, the

increased use of PCs, the

increased number of staff and

effects of higher summertime

temperatures has meant that the

internal environment had

become unbearable by 1999.

Twenty seven Monodraught 1m

square Windcatchers were

installed at approximately 25% of

the cost of air conditioning with

remarkable results. All problems

of overheating and poor air

quality have been eliminated and

the 500 staff now enjoy fresh air

into their offices throughout the

year and all this without costing

hardly a penny in running costs.

Windcatcher NaturalVentilation systemsThe Monodraught Windcatchersystem has proved to be the mosteffective method of providingnatural ventilation to anycommercial building, byencapsulating the prevailing windfrom any direction. Clean, fresh air,relatively free from contaminationor traffic pollution, is entrained atroof level and is carried down tothe rooms below through acontrolled damper arrangement.The ventilation effect is similar todisplacement ventilation.

Night time cooling is achievedwithout compromising the securityof the building. Warm stale air isexhausted by the passive stackquadrants of the Monodraughtsystem and replaced by cool freshair taken in from roof level.

This Windcatcher arrangement,pioneered by Monodraught, is nowwidely recognised as the mostreliable and effective means ofharnessing the wind’s potential asa renewable energy source.

Initial capital costs are often lessthan half the cost of airconditioning and there are norunning or energy costs.

Natural Ventilation systems

Detail of Windcatchersinstalled for WH Smith Ltd.

Extensive use was made ofexternal solar shading to the

existing building, so as toreduce the effect of solar

gain to these offices insummer months – but all to

no avail – hence the need foradditional ventilation!

11 of the 27 Windcatchers installedat WH Smith Headquarters.

4 Monodraught

MonodraughtWindcatcherThe Driving ForceWind DrivenWind movement striking theMonodraught system is capturedby the louvres serving the quadrantsand internal turning vanes on thewindward side turn the air through90°. The force of the wind is drivendown into the room or space belowand, having a greater density thanthe internal air, this cooler incomingair flows down to floor level whilstthe less dense warmer internal airrises and exits through the passivestack quadrants as a form ofdisplacement ventilation. As thewind changes direction at rooftoplevel, the system quadrants alsochange their function to continuallyprovide the incoming air andextract stale air from the building.

Temperature DrivenStack effect is achieved as a resultof the difference between the airtemperature inside and outside ofa building – and the subsequentimbalance effect on air density andpressure gradient of the internaland external air masses, results inthe warm air rising up through thequadrants.

Putting the wind to work

Kings Hill Offices,West Malling, KentClient: Tonbridge & Malling

District CouncilConsultant: Bailey & AssociatesContact: Steve BaileyContractor: Try Accord

A total of 15N° Monodraught

Windcatcher systems were

installed to these newly built

Council Offices designed to be

as ‘green’ as possible. The

Windcatchers provide natural

ventilation to both First Floor and

Ground Floor offices.

The Building Engineering

Department of Brunel University

have carried out two

in-depth monitoring studies

during the summer months of

2001 and 2002 at Kings Hill

Offices and submitted a Paper

on the results to the World

Renewable Energy Congress in

Cologne in July 2002.

Due to the success of the

Windcatcher systems installed at

Kings Hill Offices, Kent County

Council have said they are

looking to use Monodraught

systems wherever possible in

their future building programme

for both new build and existing

buildings.

Internal views of the officesshowing the diffusers serving

the first floor and ground floorareas, with the main air duct

passing down through the firstfloor offices.

Monodraught 5


Fire Dampers andSecurityFire dampers can be incorporatedinto the design of the Monodraughtventilation stacks without havingany bearing on the effectiveness ofthe natural ventilation system. AllMonodraught systems aremanufactured in 3 ply glassfibrewith Class 0 fire retardant resin.

Clearly it is not possible to breakin to or out of a building throughthe Monodraught Windcatchersystem but, nevertheless, stainlesssteel security grilles can beincorporated into the base of thesystem.

Noise TransmissionThe Monodraught Windcatcherswere submitted to the BREAcoustics Centre in January 2002for a series of tests. It wasestablished that in its standardformat, the arrangement of theWindcatcher systems has theeffect of reducing noisetransmission by 26dB ascompared to an open window. Byincorporating 15mm acousticlining to the trunk, a minimum of afurther 10dB was achieved. Acousticpods or other forms of attenuationcan also be incorporated.

University of BathTennis Halls,Bath, Avon

Client: University of Bath, Estates Department

The Tennis Halls are used once

a year for the Graduation

Ceremonies held over two days

and presented an unusual

challenge to Monodraught. As

can be seen from the charts on

the right, internal temperatures

of up to 28°C were reached in

1997 and the internal air quality

was appalling. This was all cured

by the Monodraught Windcatchers

installed in 1999.

In 1997 there was a 12°C rise in internaltemperature and a distinct lack of fresh air. By1999, after the Windcatchers were installed,the rise was limited to 7°C and air qualityimproved.

Sheffield Secure Unit,Limb Lane, Sheffield

Specifier: Sheffield City Council Design & Build ServicesArchitects: Mr David Pollitt and Mr Tony Blackstock

Seventeen Windcatchers installed, serving bedrooms, staff rooms and

corridor areas. The building was completed in March 1997 and is one of a

number of important ‘green’ engineering projects by Sheffield.

6 Monodraught


Night-Time CoolingNight-time cooling or ‘free cooling’is considered to be one of the mostimportant aspects of natural ventil-ation strategies. The night-timecooling facility provided by theMonodraught Windcatcher systemenables the building to become anintegral part of the ventilationstrategy. By cooling the structureand the fabric overnight, the buildingcan become homogeneous withthe ventilation strategy by absorbingsome of the heat as a heat sink,resulting in lower daytimetemperatures.

The volume control dampers at thebase of the Windcatcher systemscan be programmed to open fullyat, say, midnight to encapsulate thecool night air. Any prevailing windcarries this air down into thebuilding below.

The ‘cleansing’ effect of the down-wash of cold air leaves the buildinginterior feeling fresh and clean forthe benefit of the occupants arrivingin the morning. The dampers wouldnormally be programmed to closeagain at, say, 6am and a temper-ature set limit of 15°C can beintroduced to ensure that thebuilding is not over-cooled. All this,without compromising the securityof the building.

Kent Police HeadquartersCall Centre, Maidstone

Specifier: Kent Constabulary Main Design and BuildContractor: Try Accord

A total of nine Windcatcher systems were installed to this new Call Centre

where so often air quality, overheating and working conditions for Call

Centres has proved to be a problem. A representative from Try Accord, Mr D

Cook, said, “The Monodraught Windcatchers have been exceptionally

successful in bringing in cool, fresh air and extracting stale air from the

building, the real benefit of which cannot be overstated. One has to take into

account that this is with 80 to 100 personnel and their PCs”.

Try Accord and Monodraught have also recently installed Windcatcher systems

at the Kent Police Safety Training Centre and the Kings Hill Council Offices.

Sutton Arena, Sutton,Surrey

Specifier: William Hogan-O’Neil,Chartered Architect

Client: London Borough of Sutton

Eight 1m diameter Monodraught Windcatcher

natural ventilation systems and fourteen 750mm

diameter SunPipe natural daylighting systems

have been installed in the superb Sutton Arena

Leisure Centre, a new £4.8 million sports facility

opened February 2003, providing indoor training

facilities for international level field & track athletes,

as well as regional clubs and community groups.

The Architect said, "My whole idea from the

concept stage was to bring the outside, indoors

with daylighting and fresh air to replicate as

much as possible outside field and track facilities

in this all-weather Arena.

Monodraught 7

The cantilevered first floor running track toSutton Arena, served by the Windcatchernatural ventilation systems and SunPipes

for natural lighting.

Stage 4 : Heat GainsThe heat gains will varyconsiderably from one room toanother and depending on thepredicted solar gain, the lightingand equipment heat gains to thearea and most importantly, the heatgenerated by the occupantsthemselves, based on their activity.In the example shown this refectorygenerates a total of 16kW which hasto be dissipated to atmosphere.

Designing a NaturalVentilation SystemThe effective design of aMonodraught Windcatcher venti-lation system is carefully matchedto the volume to be ventilatedtaking into account the fresh airrequirements and heat gains to bedissipated. These calculationsfollow a recognised procedure.

Stage 1: Project BriefEach project is considered on itsown merits since no two jobs arealike and each project must beindividually assessed.

Stage 2: DataThe ventilation requirements areassessed so they relate directly tothe volume of each room and itsoccupancy. The fresh airrequirement is based on thenumber of Occupants and the useof the building ie. Class Room,Sports Hall, Office, etc.

Stage 3: Fresh AirRequirementHaving established the necessarydata, the minimum ventilation ratecan be determined dependent onthe occupancy using a recognisedcalculation method to provide thisvital fresh air requirement.

An estimation has to be made onthe building air leakage rate,dependent on many factors andbearing in mind all heat gains arecalculated on the maximum or‘worst case’ conditions. Forsummer use the assumption ismade that perimeter windows willprobably be used in addition to theWindcatcher system to provide thisnatural ventilation since, except forinternal rooms, natural ventilation

by conventional means can beanticipated to a limited extent.

Stage 5: RecommendationsHaving determined the ventilationrate required, we can select thesize and quantity of theMonodraught Windcatcher systemsfrom our in-house computerprogramme. The performance ofeach individual Windcatcher canbe assessed and therefore

matched to the requirements of thebuilding and the rooms in question.

Stage 6 : ConclusionsWe can offer a range of possiblealternative sized and shapedsystems to suit the architecturalpreference of the Client, but stillobserving the strict ventilationcriteria arrived at by our uniquecalculation method. A detailedquotation is also provided.


8 Monodraught

Windows and DoorOpeningsIn summer months, it is not unusualfor perimeter windows to be openedand this will aid cross flowventilation, with fresh air coming inthrough windows on the windwardside of the building and exhaustedthrough the passive stack elementof the Monodraught system. Warmair will naturally rise and beexhausted through this passivestack section. In addition, naturalventilation will be aided by theexternal wind movement, creating anegative or suction zone to one sideof the Monodraught system as wellas the building. This has the effectof slightly pressurising the building.

The advantage, however, of the Monodraught Windcatcher system isthat in mid-season or at week-endsand evenings when perhaps thebuilding is not being used, thesystem is not dependent onopenable windows or vents in theside of the building. When all theexternal windows are closed, theMonodraught Windcatcher will stillcontinue to operate, providing all thebenefits of this ‘free air conditioning’.The volume control dampers at thebase of the Monodraught system atceiling level will precisely control theamount of airflow through the system.


Building RegulationsComplianceAll Monodraught systems complywith Building Regulations Part F, L1and L2, and BRE Paper IP13/94.They are designed in accordance

BS 5295 : 1991

Table 4. Recommended outdoor air supply ratesType of space Recommended Minimum

Per Person Per m floor areaL/s L/s

Office (open plan) – 1.3School Classrooms 8 –Corridors – 1.3

2

with BS 5925, which is the Code ofPractice for ‘Ventilation Principlesand designing for naturalventilation’ and are based uponCIBSE Guide A for EnvironmentalDesign.

CommissioningUpon completion of the buildingand immediately prior to hand-over,Monodraught’s Control Specialistswill attend site to fully commissionthe automatic digital controlpackage to ensure that all controlstrategies are correctly programmed,to reflect the finite usage of therooms in question and programmedto suit the end user or Client’sexact requirements. Summer/wintersetting periods are agreed,together with all time settings. Alaminated instruction/ informationsheet is included for each room.

Monodraught’s AfterSales ServiceMonodraught can now provide a 12month maintenance service on allContracts. In addition,Monodraught Control Specialistscan return to site by appointmentat any time to meet with theManager of the building to “finetune” the control strategy to reflectthe Client’s current requirements,should the original requirements orspecification change. There is anominal charge for this service.

Monodraught 9

Sulphur Hexafluoride (SF6). Three

pairs of small mixing fans mounted

in opposing directions in

stands were placed in both

lecture theatres. The purpose

of the fans was to mix the

incoming fresh air with the

tracer gas inside the lecture

theatre. The tracer gas

concentration was sampled from

three points around the lecture

theatres and combined before


A four day on-siteinvestigation and reportby the BuildingResearch Establishmentsummarised below hasproved the effectivenessof the MonodraughtWindcatcher systemunder Summer loadconditions.

T E S T R E S U L T S

The University of Hertfordshire had

converted what was originally its

old mainframe computer room into

two lecture theatres, G105 and

G111. The single storey, flat roofed

building had previously been

served by a separate air

conditioning system. There were

no openable windows in either

lecture theatre. G105 is the smaller

of the two with a volume of 458m3.

G111 had a volume of 769m3.

The detailed monitoring and

measurements were carried out

from 10th to 13th August 1998.

The external temperatures were

very high for two of the days

(approx. 29°C), while for the other

two days it ranged from 18°C to 22°C.

The ventilation rates of the lecture

theatres with the Windcatchers

closed and sealed was determined

to find a base comparison.

Readings were also taken with the

dampers closed and fully open and

were measured on three days in

G105 and four days in G111. The

effect of night cooling from the

units was also determined over two

days. Flow visualisation studies

were undertaken on the units using

smoke as a tracer. A recording of

these tests was made on videotape.

It was determined that the back-

ground ventilation of both lecture

theatres (i.e. Windcatchers sealed)

was relatively low. With the Wind-

catchers unsealed and closed the

ventilation rate did not increase

significantly. With the Windcatchers

fully open the ventilation rate in

G105 ranged from 1.24ac/hr at

1.7m/s wind speed to 5.2ac/hr at

University ofHertfordshire,Hatfield

Specifier: University ofHertfordshire, PremisesDepartment

The existing Lecture Theatres

G111 and G105 constructed

with large flat roof areas, had

suffered from severe

overheating in summer months

in previous years. Four

Monodraught Windcatchers

have been supplied and

installed complete with

temperature controlled

modulating dampers to achieve

up to 10 ac/hr during summer

months and 11/2 ac/hr during

winter months.

4.5m/s. For G111 it ranged from

2.13ac/hr at 2.6m/s to 4.68ac/hr at

4.1 m/s.

The effect of leaving the dampers

to the Windcatchers open in one of

the lecture theatres overnight

demonstrated the night cooling

effect of the units. A temperature

difference of approximately 8°C

was achieved in the lecture

theatre overnight.

VentilationMeasurementsVentilation measurements were

carried out in both lecture theatres

using the tracer gas decay method,

10 Monodraught


CONCLUSION● The units supplied 960 I/s

and 636 I/s to lecture

theatres G111 and G105

at moderate wind speed.

● If 50 students occupied

each lecture theatre the

air flow rate per occupant

would be 19 l/s in G111,

and 13 l/s in G105. These

are very satisfactory levels

given these wind speeds

and temperature levels.

● Air entered the unit

through the prevailing

wind segment(s) and

exhausted through those

on the leeward side.

● There was no evidence of

short-circuiting of the air

movement.

● Night cooling by the units

provided lower overnight

temperatures.

being analysed by a B&K gas

analyser.

The local wind speed and direction

during the ventilation measurements

were measured using an ultra-

sonic anemometer mounted 10

metres above ground level at the

top of a telescopic mast.

Internal and external air

temperatures were measured every

minute, using thermistors

connected to Grant Squirrel data

loggers. Two loggers were placed

in each lecture theatre and the

values averaged. The external

temperature was measured by a

data logger and thermistor located

in a Stevenson screen (a white

ventilated enclosure mounted 1

metre above ground level).

Flow VisualisationTo observe the operation of the

Windcatcher units i.e. the air flow

in and out of the units, a smoke

machine was used to generate a

dense white smoke which was

released out through a purpose

made four-way adaptor which was

placed underneath the unit. A

videotape record of these flow

visualisation tests was obtained

along with some still photographs.

The flow visualisation study showed

that there was a vigorous flow of air

in through one or more segments

of the Windcatcher and out through

opposite segments, even when the

wind speed was approx. 2 m/s. At

approx. 4 m/s the effect was much

more pronounced with a significant

down flow of air through the Wind-

catcher towards floor level. There

did not appear to be any evidence

of short-circuiting of the fresh air.

When on an occasion the external

doors to G111 were opened on a

day when the wind speed was low

(2 m/s), brief observations showed

that air entered the lecture theatre

and was exhausted through all four

ducts of the Windcatcher system.

Extracts from this Report are

reproduced with the kind permission of

Mr Brian Webb of the BRE. A full copy

of the Report and a video are available

direct from Monodraught Limited.

11Monodraught

There are three BasicMethods of Control● Automatic Control● Remote Control● Manual Control

1. Automatic Control Panel

A fully programmable Cylonautomatic control panel is includedas standard in the Monodraughtpackage. The Cylon panels are ableto be connected to eithertemperature, air quality, CO2 orhumidity sensors, depending uponthe particular application.

The Cylon panel can be located in aplant control room, it does not needto be located in the room that it isserving. Cylon panels can servemultiple rooms, up to eight Class-rooms can be served by one UC16panel with the following controls.

TemperatureOne or more temperature sensorsare positioned in the room toachieve an average reading. This isthe simplest method of Automaticcontrol and is suitable for mostapplications.

Summer/Winter switching enablesthe temperature set points to beincreased in the winter setting toprevent heat loss during this period.

Standard Temperature sensor withmanual override.

Typical wiring diagram Internal detail of a typical Cylon panel.

Standard Windcatcher Sensor approach to a typical classroom block.


12 Monodraught

Air Quality In the case of highly denselypopulated rooms, such as ConferenceRooms or social areas, air qualitysensors are recommended inconjunction with temperature sensors.

CO2/HumidityFor more specialised applications,dedicated CO2 and/or humiditysensors can also be incorporated.

Room SensorsSensors should be ideally locatedapproximately 1.8m from floor levelin an area to which there is nodirect heat gains, such as nearwindows or above equipment.

Manual OverridesA green push button manualoverride is incorporated on thetemperature sensor or mounted onthe face of the Cylon panel. Themode of operation is as follows:First push hold for two seconds andthe dampers will remain open for onehour (20 minutes in the winter) beforereturning to their pre-set position.Second push and hold for twoseconds the dampers will thenclose fully, irrespective of thecontrol panel and will then return totheir pre-set condition after one hour(20 minutes in the winter).Third push and hold for twoseconds will automatically returnthe settings to the control panel.


2. Remote ControlThis is a less sophisticated controlmethod and provides remote controlto the volume control dampers viaan electrically operated, wallmounted positioner as shown. Theuser would simply alter thepercentage of damper opening bytwisting the dial to the desiredposition to suit the conditions.

3. Manual ControlThis is the most basic method ofcontrol. Instead of motoriseddampers, manual dampers arefitted and are operated by a leverat ceiling diffuser level. In the caseof high ceilings or where access tothe dampers is limited, Monodraughtcan provide a manual windingmechanism. As with the RemoteControl method the user wouldsimply alter the percentage ofdamper opening by operating thelever to open the dampers to thedesired position to suit the conditions.

End UsersMonodraught supply a laminated A4sheet as standard with every Project,as part of the operating andmaintenance manual, this instructionsheet outlines the controls strategyfor that particular Project require-ment. Because the panel is fullyprogrammable, the strategy can bealtered easily on site should itrequire any fine-tuning.

Summer and WinterOperationNatural ventilation is primarily aimedat the summer season. The summerperiod is normally programmed torun from April (ie. after the heatingseason is finished) through to theend of September, .

Under summer operation, thedampers are programmed to suitthe building requirements, but ournormal recommendation is tocommence opening at 16°C to thefollowing settings:-

17°C 20% open18°C 40% open19°C 60% open20°C 80% open21°C fully open

Under winter operation fromOctober through to April, thedampers can either remain closedor be set to 5% open to providetrickle ventilation depending uponthe requirements.

Alternatively, for winter operation, theset point to commence opening canbe set at 22°C, so that at 23°C thedampers would be 20% open. Thissetting allows for any freakconditions, such as 'Indian summer'or early solar gain, which may occurduring the 'winter' season.

Monodraught 13

Wall mounted Remote Positioner. Manual lever/grille detail.

Typical Controls Strategy Sheet for End Users

Night Time CoolingThe added benefit of night time

cooling cannot be overstated. The

normal approach is to program the

dampers to open fully at 12.00

midnight to allow the cool night air,

assisted by any wind movement, to

enter the building through the

Monodraught Windcatchers and

plunge to floor level. This purges

the building of stale air and means

that the internal building fabric and

structure will be cooled overnight

to well below daytime temperatures.

This night-time cooling effect

leaves the building fresh and clean

for when the occupants arrive in

the morning. It is probably only by

late afternoon that the ingress of air

temperatures in excess of 25°C

and solar gain will have raised

temperatures internally. However,

even with these ambient

temperatures during daytime, the

benefit of the Windcatcher

systems, having operated

throughout the night time, will be

apparent with the constant

downwash and movement of air

being maintained, which together

with natural passive stack

ventilation, removes the ‘stuffiness’

that so often plagues buildings

during summer months.


HM Treasury, Whitehall,London

Architect: Foster & PartnersContractor: Bovis Lend Lease Ltd

A total of 13 No.1000mm square and 2 No.

2000 x 1000mm Monodraught Windcatcher

systems were installed to what is believed to

be the first major Government Building in

Whitehall to be naturally ventilated.

Air-to-Air HeatRecovery System forWinterMonodraught have developed anall plastic, fresh air-to-air heatrecovery unit, specifically designedto provide cost effective ventilationduring winter months forclassrooms and offices. With atypical airflow rate of 900m3/hr, thiswill provide 8 l/s per child (currentlydemanded for Schools) in a typicalclassroom size of 30 pupils.Features include very low noisecentrifugal fans with variable speedcontrols, to allow location in theclassroom space. A unique highefficiency plate heat exchanger(sensible efficiencies in excess of65%) made from re-cycled plasticensures that the system is virtuallyunbreakable and maintenance free.

14 Monodraught

Bridgetown,Barbados

Consultants:Leverage Inc., Barbados

Ten GRP 800 Windcatchers were

designed and installed by

Monodraught to serve an indoor

food market. The gentle offshore

sea breeze provides the perfect

driving force for Monodraught

Windcatcher energy free natural

ventilation systems. Since the air

temperature in the West Indies

remains the same throughout

the year, there was no need for

volume control dampers at the

base of the systems and despite

the fairly constant high

temperatures the Windcatcher

systems still proved extremely

effective by providing a

permanent ventilation, not only

taking out food odours but also

encapsulating the cool,

refreshing sea breeze. This

Project demonstrates the wide

versatile nature and energy-free

operation of the Monodraught

Windcatcher systems, which are

now being specified for Projects

throughout the world.


Upstand Details to suit 600 Circular Monodraught systemfor a Tiled Pitched Roof Application

Isometric Detail of Upstandfor Circular system

Typical Upstand detail to suit Monodraught Square systemfor a Pitched Metal Decking Roof Application

Isometric Detail ofRoofing Sheet

Upstand Details to suit 600 Square Monodraught systemfor a Tiled Pitched Roof Application

Isometric Detail of Upstandfor Square system

Upstand Details to suit Monodraught 600 Circularsystem for a Flat Felt Roof Application

Isometric Detail of Upstandfor Flat Roof

Upstand Detail to suitMonodraught Square systemfor a Flat Concrete RoofApplication

InstallationThe installation of the MonodraughtWindcatcher system is relativelysimple and the standard upstanddetails shown below normally apply.

UPSTANDS AluminiumFor a standing seam/aluminiumprofile roof a welded upstand shouldbe provided by the roofing contractoras part of the normal roof coverings.Alternatively Monodraught caninclude this work as part of theirpackage.

Existing RoofsFor existing metal profile, tile or slateroofs Monodraught can provide apurpose designed GRP mouldedflashing/soaker sheet for circularsystems for each individual Projectas part of their package.

Slate or TileFor a slate or tile roof an 18mmexternal quality plywood upstand isrequired, covered with Code 4 leadand this is normally provided by thebuilder.

Flat RoofFor a flat roof of asphalt or built upfelt roofing, Monodraught canprovide a galvanised or GRP soakersheet to be built in by the builder.Alternatively, a conventional plywoodupstand should be specified.

Single Ply MembraneFor a single ply membrane roofsuch as Sarnafil Monodraughtprovide a GRP soaker sheet that isfitted to the roof deck and thesingle ply membrane is heat sealedin place.

Please Note:The measurements shown belowrefer to a standard 600mm system,but are typical of the tolerancesrequired for the complete range ofMonodraught Windcatcher naturalventilation systems.

Installation ServiceMonodraught can provide a fullinstallation service for all systemsthroughout the UK as part of thestandard package, or will providefull working drawings for on-siteinstallation.

All Monodraught systems feature:

•Specially designed louvres to prevent rain ingress

• Insulated volume control dampers

•Low resistance internal ceiling diffusers

•Detailed computer modelling for each contractat design stage including CFD where appropriate

•A 25 year guarantee

Monodraught 15


St Annes School, Haute Vallée, JerseyArchitects: plb architecture, WinchesterConsulting Engineers: DJ Hartigan, Jersey

The Windcatchers installed at the £12 million Haute Vallée School were

runners-up in the prestigious British Steel sponsored Design Sense Award

product section where 60 entries from 16 countries were short listed. The

Windcatchers were the only British entry short listed. The Architects, plb

architecture, in their supporting letter stated, "throughout the hot summer of

1998 there were no reports of overheating despite all the classrooms being

used to capacity." The long curved, fully glazed corridor faces due south

and it is indeed a great compliment to the Windcatcher systems that no

overheating occurred despite the fact that no form of air conditioning or

mechanical ventilation was in use.

Multi Floor OperationThe 24 Windcatcher systemsinstalled at St Annes School,Jersey, serve classrooms on bothground floor and first floor, but inaddition, the Monodraught systemsprovide ventilation to the adjoiningcorridors. Internal dividers and windturning vanes within the MonodraughtWindcatcher system are designedin such a way to ensure that bothintake and extract by naturalventilation will take placeirrespective of wind direction.

16 Monodraught

1000mm diameter ducts conveying ventilationair to ground floor Classrooms.


Research & DevelopmentMonodraught is currently sponsoringresearch at six Universities; UMIST,Nottingham, Brunel, Napier,Loughborough and Reading tofurther develop natural ventilationand natural daylighting systems.

BSRIA with collaborative researchfunding from the DTI are developinga design and application guide forroof mounted natural ventilationsystems. Monodraught, as one ofthe partners of this research, willprovide a technical input into theguide. The work started inNovember 2002 runs over a periodof 18 months and aims to improveconfidence and encourage thewidespread uptake of natural venti-lation systems through the develop-ment of practical, robust and reliablemethodologies for sizing thesesystems. The project will involve amixture of laboratory and field trials.

Monodraught continue to pursue an

active policy of examining all

possible developments of low

energy concepts. Further research is

being directed at solar driven extract

fans that may be used in

conjunction with our passive

ventilation systems and innovative

heat recovery systems, all designed

to unlock the huge potential of

naturally driven ventilation systems.

Queen Elizabeth Sixth Form College,Darlington, Co Durham

Architect: Browne Smith Baker, Darlington

The area once formed an open courtyard, which was roofed over to provide a Library and IT Room. 6 No. GRP 1000

Windcatcher systems were installed through a new concrete roof, to provide natural ventilation – and the College

landscape gardeners were given a free hand to provide an attractive garden-like setting for the new Windcatchers. The

Architects remarked that ever since the building was occupied there had been nothing but praise for the natural ventilation

provided by Windcatchers as compared to the adjoining, air conditioned, IT Room. A far more pleasant working

environment is immediately noticeable to everyone using the school.

M O N O V E N T

Whereas this brochure is aimed atthe larger scale WindcatcherNatural Ventilation systems forcommerce and industry, it isrecognised that there is a greatdemand for smaller MonoventSunCatcher systems for Homes,Doctors’ Surgeries, Shops andOffices, etc, as well as Domesticresidential properties.

Monodraught produce two sizes,ABS 350mm and 550mm diameterMonovent SunCatchers. Full detailsare provided in a separate brochure.

These smaller systems are availableeither as simple Monoventventilation systems or MonoventSunCatcher light and ventilationsystems.

Monodraught 17


MonodraughtBespoke SystemsSuch is the versatile nature of theMonodraught systems that they canbe used on a wide range ofconventional discharge or ventarrangements, providing the benefitsof maintenance free architecturallydesigned outlets to compliment anybuilding.

Mixed mode applications werefavoured in the late ‘90s for naturalventilation where doubt wasexpressed that natural ventilationcould indeed be effective throughout summer months. Monodraught’sexperience has been that wheresuch mixed mode or fan assistedprovision has been made in thepast, the fans have never actuallybeen called into use, such is thehighly effective nature of theWindcatcher system. Neverthelesssuch provision of fan assistance canbe made without unduly affectingthe performance of the system undernatural draught conditions.

Monodraught’s design team willcalculate the louvre area required,together with any spigot connectionsthat may be necessary, but all otherflashing details and installationrequirements will be the same as forany other Monodraught system.

The Press Association, Howden, East Yorks.

Old Hill Primary School, West Midlands.Bluewater Retail Park, Dartford, Kent.

Old Hill Primary School, West Midlands.

The Oxo Tower Restaurant.

The National Osteoporosis Society Headquarters, Camerton, Nr Bath, Avon.

Monodraught18

Collier House, Brompton Road, Chelsea.

Oriel House, Nr. Marble Arch, London.

Restaurant, Lisson Grove, London.

University of Hertfordshire, Faculty of Artand Design.

Chingford Hall Community Buildings, Essex.

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Putting the sun and wind to work

Natural ventilationand natural lightin a single installationThe Monodraught SunCatcher hasproved to be highly popular as acombination of natural daylight andnatural ventilation in one combinedsystem.

The heart of the MonodraughtSunCatcher system is the SunPipe,which is a mirror-finished, highlyreflective aluminium tube, which isan electrolytically enhancedanodised aluminium substrate witha pure silver base. The systemcarries a 25 year guarantee againstdiscolouration. This specularaluminium surface is coated withPVD and the presence of a UVinhibitor provides outstanding QUVdurability with no decrease in totalreflectance. The special surfacetreatment provides excellent colourrendition of natural light.

The SunCatcher is the idealalternative to rooflights and skylights.It is also an ideal method forproviding additional natural daylightand ventilation to internal rooms orspaces, poorly served by otherexternal glazing.

The SunPipe system, which iscombined with the MonodraughtWindcatcher, to provide theSunCatcher system, maximises theconcept of renewable energy bynot only reflecting and intensifyingsunlight and normal daylight downthrough the mirror-finished internaltube but also to provide all theventilation requirements on thesame basis of the Windcatchersystem. With the case of theSunCatcher, four motoriseddampers are incorporated at thebase of the system to exactlycontrol the airflow.

Monodraught SunPipes, which aredescribed in a separate brochure,are currently produced in tendifferent sizes ranging from 200mmto 1500mm diameter as standard.SunCatchers are manufacturedfrom 400mm to 1500mm bothcircular and square.

Please ask for separatebrochure on SunPipe andSunCatchers.

26 of our 1200mm square SunCatcher systems installed at BMW Design & Facilities Offices atCowley, Oxford. Architects and Consulting Engineers: W.S. Atkins.

putting the sun andwind to work –

it’s only natural!

Monodraught

Detail of the base of the SunCatcher wherethe SunPipe features the BMW logo.

Internal and external viewsof Natures World,Middlesborough, where a2.3m diameter bespokeSunCatcher system wasinstalled, incorporating a1500mm dia. SunPipe.The ceiling diffuser is sitedapprox. 6m above floorlevel and provides anabundance of natural light.

The ‘famous’ Eco House at Nottingham University whichhas had wide publicity in the Architectural press, featureda bespoke pinnacle SunCatcher system, with apolycarbonate cone.

Monodraught 19

MonodraughtHalifax House, Cressex Business Park, High Wycombe, Buckinghamshire HP12 3SE

Tel: 01494 897700 Fax: 01494 532465email: [email protected] www.monodraught.com July 2003

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