Passive House Seminar for the Professionals from the Building Sector

Passive House Seminar for the Professionals

from the Building Sector

Passive House Seminar for Professionals from the Building

Sector

DAY 2

Design – Ventilation systems


Sector

Day 1What is a Passive House?Design According to the Passive House CriteriaDesign – Heating Systems and Energy SupplyDesign – Solar Energy UtilizationPlanning and Concept DevelopmentRealization and Construction Processes

Basic educational course about Passive Houses,organised by a local partner in the European funded PASS-NET project

Passive House Seminar for Professionals from the Building Sector

Day 2 Design –Ventilation systems

Day 2Planning and Calculations – introduction to PHPPEnergy Statistics, Standards and CertificationsDesign – Air tightnessDesign – Ventilation systemsDesign – WindowsRegional examples of built Passive Houses


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Main purpose of ventilation systemsRemove polluted air

– CO2

– Pollutants, particles– Moisture

Supply fresh air– Heating– Cooling

Picture: Ulla Janson

Day 2 Design - ventilation systems

Good ventilation is important for both our health and for the sustainability of the building Indicators of insufficient and inadequate ventilation may be:

Condensation on the internal window glass pane during winterA perception of the air as being stuffy or ”heavy"Lingering condensation on bathroom mirrors after showers and baths

Day 2 Design - windows


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Principles of ventilation

Natural ventilation– In buildings with natural ventilation

there is no mechanical fan. The air is let in by leakages and planned air slits and is exhausted in exhaust air pipes, often placed in the chimney stack.

Picture: The Swedish Energy Agency



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Exhaust air ventilation– In the exhaust air ventilation system

a mechanical fan is always running, creating an under pressure in the house. The supplied air is let in by leakages and planned air slits.




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Mechanical ventilation– Balanced ventilation –

air flows in and out from the building are equal



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Mechanical ventilation - Supply and exhaust air ventilation with heat exchanger

– An easy way to save a lot of energy for heating purposes in buildings– Heat exchangers in passive houses have an efficiency of 80-85%

1. Supply air 2. The cold supply air is heated in a heat exchanger by the warm exhaust air 3. Heated supply air is let in to the house4. The used exhaust air goes from the kitchen and bathroom 5. The exhaust air is getting cold in the heat exchanger and is let out



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Heat recovery

Rotary heat exchanger

Counter-flow plate heat exchanger

– Most efficient heat recovery– Might also recover odours

– Efficient heat recovery– No odours are transmitted

Picture: Swegon



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Specific Fan Power - SFP Measures how efficient a fan uses the electricity needed to move

maximum amounts of air

SFP = Ptot/Vmax (kW/(m3/s))

SFP – values for air-to-air heat exchanger units– SFP 1.5 Very efficient– SFP 2.0 Efficient– SFP 2.5 Less efficient– SFP 4.0 Waste of a high quality energy source

Example:

An air-to-air heat exchanger with a supply air fan which uses 10 kW and an exhaust air fan which uses 10 kW. Maximum supply air flow 7.9 m3/s, maximum exhaust air flow is 8 m3/s.

SFP = (10+10)/8 = 2.5



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Placement of ventilation units

Need to be easy to access for maintenance

Try to avoid noise generated by the ventilation unit fans. For instance - place the unit in a closet (if using decentralised ventilation)

Placement close to an outer wall minimises the need for insulated ventilation ducts

Picture: bsv arkitekter



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Central – decentralised ventilation

Central units• One large unit needs less time for maintenance• Easier to find adequate space needed for silencers • Need careful planning with regard to fire-safety (if separate heating

batteries are placed in each apartment)

• Decentralised ventilation units• Each tenant can easier control their indoor climate• Need careful planning regarding

- placement to avoid insulation of pipes- find enough space for silencers - avoid short cut of air in inlet and outlet of air



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Central or decentralised ventilation ?

Factors to take into consideration in the selection process:– Available space for

• Ducts and silencers;– is there a need for lowering the ceiling if using decentralized

ventilation?- is there enough space in the attic to install ducts? - is it possible to place shafts in stairwells?

• Ventilation unit;– can it be placed in the attic or cellar? – is it possible to place in apartments regarding the need to

obtain acoustic level requirements?

– How will routines of maintenance be performed concerning...• filter changes?• adjustment of heating batteries?



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Indoor comfort

The indoor climate is a combination of the four technical climates;

– Air hygiene– Thermal climate– Acoustic climate– Visual climate

Picture: Ulla Janson

Supplied air - in rooms for daily get-together activities and in bedrooms (rooms with high air quality)

Transferred air – from rooms with high air quality to rooms with lower air quality

Exhausted air – from bathrooms and kitchens (rooms with low air quality)



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Air distribution

The supplied air creates a comfortable indoor climate in the occupational zone

If the building is heated/cooled by air, the supply air devices must be customised for both warm and cold supply air temperatures

Picture: Swegon

Documents

Passive House Seminar for the Professionals from the Building Sector