Passive Schools
Air Temperature
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Passive Schools provide excellent comfort levels with low running
costs and less equipment to be maintained or replaced. The extra
build costs are easily offset by the smaller heating system.
A Passive School maintains a stable year round temperature using
extra insulation, higher air tightness levels, HRV and better
windows, so the temperature rarely falls below 17 degrees.
The classroom is heated by the pupils who produce 2kw (25 kids x
80w = 2kw) plus 2kw Solar Gain plus 1kw from a radiator used for 1
hour in the morning before the kids arrive. This radiator will use less
than €100 worth of energy per year, so when the heating system
doesn’t work for 2 weeks in winter nobody notices. The classroom in
a Passive School loses 1 degree overnight and heating costs are
reduced to 10%.
www.viking-house.ie
1
Riedberg school, Frankfurt
basic facts
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Opened in
Area
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Occupants
Construction type
Ventilation
Heating
Air tightness
Extras
2004
8,000 m²
(6,300 m² + gym)
650 – 675
Concrete externally
insulated
HRV
Wood pellet boiler
n50=0.46/h
30 kW photovoltaics
www.viking-house.ie
2
Riedberg school, Frankfurt
energetic performance
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Calculated heat demand
U-value walls
U-value window frames
U-value glazing
U-value roof
U-value ground slab
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Temperatures during the winter
between 19.5 and 20.6 °C
Almost no overheating during the summer
Average in 2006 (warm summer) was 22.9 °C
CO2 concentration is constantly below the recommended threshold of 1,500 ppm
Heat consumption during the winter of 2005/2006 was 90 % below German standard
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15 kWh/(m²a)
0,17 W/(m²K)
0,8 W/(m²K)
0,6 W/(m²K)
0,11 W/(m²K)
0,21 W/(m²K)
www.viking-house.ie
3
Overheating Control
Draught free building
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Summer overheating is easily controlled by cooling the Thermal
Mass using automatic actuator controlled vents at night and closing
blinds within the windows by day. If the classroom gets too hot, just
open a window~even in winter!
The heat generating kitchen is kept to the North side of the building.
Earth heat exchangers deliver 15-16 degree air when its 25 degrees
outside and 7 degree air when its minus 10 degrees outside. This
simple technology cuts the size of your heating or cooling system in
half.
Cold surfaces and leaky buildings cause draughts. The 17 degree
surface temperature of Passive School windows stops convection
and the high level of air tightness ensures the building is draught
free, so the child near the windows isn’t cold.
www.viking-house.ie
4
Riedberg school, Frankfurt
costs
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Total
Additional costs
Construction costs
Est. payback period in 2003
Est. payback period in 2005
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With oil prices hitting 130 $ / barrel
payback period is even shorter today
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After payback period energy savings of
several thousand euros per year
16.7 mio €
~3%
1,110 €/m²
30 years
12 years
www.viking-house.ie
5
Cold Bridge free Construction
Warmer Walls
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Cold Bridging is eliminated at
design and construction
stages, delivering walls
without cold spots.
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With a 15 degree wall, the
thermostat is set to 25
degrees for comfort, with a
19 degree wall, the stat is
lowered to 20 degrees.
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Warmer surfaces reduce
condensation eliminating
fungus/mould growth.
www.viking-house.ie
6
Heinrich v. Kleist school, Frankfurt
basic facts
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Opened in
Area
Construction type
Ventilation
Heating
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Air tightness
Extras
2007
1,338 m²
extension, concrete
Wolf KG 160 Gigant
shares heating with
existing building
n50=0.24/h
green roof
insulation is
CFC-free
www.viking-house.ie
7
Lighting
Biomass-PV
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Lighting is the single biggest energy guzzler in British Schools and its
excessive use can be easily reduced by adopting Passive School principles.
Lights in UK schools often default to on because the controls are too
complicated. Passive Schools usually have 3-3.5m high ceilings and
windows are high in the walls to deliver natural light across the whole
classroom. Up lighters that light the ceiling are a no-no, all lights should
automatically switch off at break time and be manually switched back on.
Night time security lights are operated by motion sensors that only work
after dark.
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Biomass boilers can be a maintenance nightmare if you pick the wrong
model and PV often doesn’t do what it says on the tin, but they both need
replacing every 15 years.
If the only difference between a Code 4 and a Code 6 school is the size of
the PV array? then It makes more economical sense to build a PassiveCode 4 school and buy in Green Zero Carbon electricity.
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www.viking-house.ie
8
Heinrich v. Kleist school, Frankfurt
energetic performance / costs
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Calculated heat demand 14 kWh/(m²a) = 1.4 liters of oil per square meter per year
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U-value walls
U-value window frames
U-value glazing
U-value roof
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U-value ground slab
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Total costs:
Construction costs:
0.126 W/(m²K), Rockwool
0.81 W/(m²K)
0.6 W/(m²K)
0.095 W/(m²K)
EPS insulation
0.144 W/(m²K)
EPS and foam glass
2,692 €/m²
2,053 €/m²
www.viking-house.ie
9
Humidity
Air Quality
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Humidity is controlled using HRV during the heating season and natural
ventilation for the rest of the year. The ventilation rate for a Passive School
is based on the occupancy levels, not on the volume of the building as per
the UK building regs.
The Passive Schools with the lowest Co2 levels use HRV, and the
performance of the pupils is 20% above average, so they can spend 2-3
years less in school (joke).
Without HRV the ventilated energy losses are massive and air quality is low,
500 pupils require 20m3/hr = 10,000m3/hr + 10% ~ 11,000m3/hr regardless
of how voluminous the building is.
HRV for a 300 pupil school costs €150,000 which is cheap when you
consider the benefits achieved from higher air quality and energy efficiency.
Children need more air than adults and are more sensitive to low air quality.
The Co2 level was below 1000ppm for 99.9% of the time in the 1st Belgian
Passive School. Low air resistance ductwork is beneficial to avoid draughts.
www.viking-house.ie
10
Preungesheim primary school, Frankfurt
energy performance
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Calculated heat demand
U-value walls
U-value window frames
U-value glazing
U-value roof
U-values floor/ground slab
15 kWh/(m²a) = 1.5 liters of oil per square meter per year
0.13 W/(m²K)
0.8 W/(m²K)
0.6 W/(m²K)
0.092 W/(m²K),
0.133 – 0.164 W/(m²K)
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Total costs
Construction costs
Calc. payback period (2008)
21,85 mio €
1.41 mio € / 1,538 €/m²
9.3 years
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Construction time
Area
Occupants
05/2006 – 08/2007
5,152 m²
530
www.viking-house.ie
11
Consultancy
Quality Control
We can guide clients through the Passive Schools labyrinth by offering the following
services:
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Get involved in your project at the design stage to optimise building orientation
and shape to reduce its energy demand
Cost benefit analysis calculating the payback period for any extra costs incurred
building your Passive School
(PHPP) Passive House Planning Package calculations
Cold Bridge (CB) calculation and elimination using Therm
Condensation risk analysis and drying ability of your wall build up using WUFI
Supply and fit of our CB free PassivHaus certified foundation system delivering
U-values as low as 0.08
Guaranteed Airtightness result of n50=0.60/h from our Airtightness SWAT team
Passive House certification on completion
www.viking-house.ie
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