Low energy ventilation
systems
CIBSE Natural Ventilation Group
Lee Hargreaves BEng (Hons) CEng MCIBSE MEI
Associate Director
Importance of ventilation – location
*Outdoor air can no longer be automatically
considered as a clean air source suitable to
dilute indoor pollutants
*CIBSE TM40 Health Issues in Building Services
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Importance of ventilation – noise & local air quality
www.defra.gov.uk/
noisemapping
http://www.airquality.co.uk/
*CIBSE TM40
Importance of ventilation – internal sources
Ventilation systems cannot remove pollution but suitably dilute
Filters on mechanical equipment remove particle matter
not gaseous matter
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The importance of ventilation
Provision of fresh air (oxygen)
Prevent the build up of carbon dioxide
Health & Wellbeing
Dilute odours
Exhaust pollutants
Remove heat gains
Energy exchange mechanism e.g. Delivery of
heat & coolth
Thermal comfort
Key design criteria – selecting the right system
Location
Design
Criteria
Environment
Form,
Shading
and
Mass
IAQ
Use of space
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Key design criteria – selecting the right system
Noise
Location
Environment
Pollution
Design
Criteria
Form,
Shading
and
Mass
Occupancy
density
IAQ
Use of space
Function
Key design criteria – selecting the right system
Noise
Temperature
response
Location
Environment
Pollution
Design
Criteria
Form,
Shading
and
Mass
Occupancy
density
IAQ
Internal
Gains (e.g.
equipment)
Use of space
Function
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General principles – thermal mass
Density (kg/m3) = Temperature / Time
response (ºC/ hr)
General principles – thermal mass
Summer
Temp
Range
Source: CIBSE AM10
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General principles – influencing the layout
System Parameters
Requirements
Single sided – single opening
Double sided – double opening
Cross ventilation
Source: CIBSE AM10
Ventilation systems – the options
Natural
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Ventilation systems – the options
Natural
Mechanical
Ventilation systems – the options
Natural
Mechanical
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Ventilation systems – the options
Intermittent
operation
Natural
Mixed
Mode
Mechanical
Building physics – modelling performance
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Temp (ºC)
Volume (l/s)
Building physics – modelling air and thermal performance
Concept & scheme design – the process
Stage A
• Appraisal
• Form
• Shape of
building
• Options
analysis
• Controls
strategy
Stage B
System Parameters
•Requirements
Brief
•
•
•
•
Heating
Ventilation
Cooling
Plant
equipment
• Cost
review
REVIEW
Stage C
• Concept
• Outline
proposals
• Outline
Spec
• Prelim cost
plan
REVIEW
REVIEW
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Case study – northamptonshire academies (12,000m2)
Kettering Science Academy
Client:
NCC
Architect:
Nicholas Hare
MC:
W Dixon
Natural / Mixed Mode
Integrated structural
ventilation
GSHP & PV
Case study – KSA building physics
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Case study – KSA key design features
Client brief low WLC building
Elevation / façade design (60/40)
Brise soleil / vertical purge
Light shelves
Low internal gains - ICT
Low energy lighting
Occupancy density
Case study – KSA (base case stage A – C)
A – Heating
- Integrated wall mounted emitters (local control)
B – Ventilation - Boost extract (winter constant, summer night cooling)
C – Plant
- Roof level Air Handling (supply & extract)
C
B
A
B
A
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Case study – KSA (option 1 stage A – C)
A – Heating
- Integrated structural ventilation (heating and cooling)
B – Ventilation - Return Air path via attenuated bulkhead
C – Plant
- Roof level Air Handling (Zonal control)
C
A
B
B
A
Case study – KSA integrated structural ventilation
Internal design (18 and 28OC)
External design (<18 and >28OC)
Efficient heat recovery system
Optimised façade design
Enhanced thermal performance
Design for mixed mode
Source: Tarmac
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Case study - control philosophy (natural ventilation)
AHU
OFF
OPEN
AVCD
Air Handling (with heat recovery)
Cooling by
Ground
Source Heat
Pumps
Automatic volume control dampers (AVCD)
Slab / zone temperature detectors
Window contactors linked to Building Energy System
Case study – control philosophy (mixed mode)
AHU
ON
C
CLOSED
AVCD
Air Handling (with heat recovery)
Automatic volume control dampers (AVCD)
Heating by
Ground
Source Heat
Pumps
Slab / zone temperature detectors
Window contactors linked to Building Energy System
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Case study – LJMU design academy (10,500m2)
LJMU design academy
Client:
LJMU
Architect:
Rick Mather
MC:
Wates
Natural / Mixed Mode
Heavyweight thermal mass
Biomass
RIBA award North West
Case study – LJMU design academy (10,500m2)
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Case study – mixed mode ventilation with thermal mass
OPEN
Exposed concrete for thermal
mass “radiant coolth” effect
CLOSED
Supply and return air from bulkhead
Case study – LJMU façade design and modelling
Elevation and section review of openable free area
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Case study – LJMU design academy (10,500m2)
Thankyou
Email: [email protected]
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