Transcript A passivhaus building is a fairly airtight design that has

Sustainable Buildings – five examples
Presentation produced by CAT Education for the
EPSRC funded project run by De Montfort University
Sustainable Buildings – recent examples
Canolfan Hyddgen –
educational building with
council offices, Machynlleth
Y Senedd – the
Parliament building,
Cardiff
St Lukes primary
school,
Wolverhampton
WISE at the Centre for Alternative
Technology -teaching spaces and
accommodation
Welsh Assembly
Government office
building, Aberystwyth
Where does the architect start?
The biggest impact buildings have on the planet is in the energy used
in them. The largest amount of energy is normally used to heat the
building but educational buildings often also use a lot of energy to
run electrical appliances and lights.
What’s important in an educational building?
What does it have to do?
Keep us comfortable - warm but not too hot
Give us enough fresh air
Provide us enough even light to be able to work
Create a calm and relaxed atmosphere
and lots more…..
Making the best use of the site
which way should it face?
All of these buildings use solar energy to heat space and for light.
Some of them also use it for heating water and generating electricity.
Canolfan Hyddgen sits next to the main secondary School site in
Machynlleth but slightly higher. It is in a wide open valley and
gets many hours of sunshine.
The windows are
protected from too
much midday summer
sun by wide eaves and
this brises soleil
This side with a lot
of windows faces
south
A wide corridor on the
south side protects the
teaching rooms from
too much direct sun
Making the best use of the site
which way should it face? 2
The Centre for Alternative
Technology sits in a valley with a hill
to the South so WISE had to be
designed carefully to make as much
use of the solar power available as
possible
St Lukes primary School is on an open site
and is faced to use solar energy for light
without overheating the building
WISE
WISE - Making the best use of a site
Large solar system –
heating water for
the bedrooms below
Daylighting from
rooflights
Passive solar
space heating
of bedrooms
bedrooms
workshops
courtyard
Passive solar space
heating
foyer
Section of the WISE building
lecture theatre
South
Solar gain – Walls that stop heat from escaping and walls that store heat
Solar energy coming
through the south facing
windows of Canolfan
Hyddgen provides 1/3 of
the heating. The solar
energy falls on the solid
floor and internal walls
and their thermal mass
stores the heat overnight
Canolfan Hyddgen
Triple
glazed
windows
Warmcel insulation
- made from
recycled
newspapers
solid internal
walls and floor
= thermal mass
highly insulated
external walls
using Warmcel
Solar gain - and then storing the sun’s energy as heat - WISE
Double glazed
low E windows
Rammed
earth
wall
On the south side of WISE
a glazed area encloses the
wall of the lecture theatre.
The solar energy falls on
the solid, dense earth wall
which stores the heat
overnight because of its
thermal mass.
The external walls in WISE
are a 50cm thick mix of
hemp and lime insulation.
Other internal walls
on the ground floor
in WISE are also
dense - made of
unfired earth blocks
Ventilation – keeping air fresh and staying cool enough
Thermal mass can take some heat out of the air but sometimes
you need to do more. Many modern buildings use air conditioning
but that uses a lot of energy.
In St Lukes the classrooms
are cross ventilated by
natural wind flow from low
level windows or vents that
can be opened to the high
clerestory windows that are
opened automatically.
Vents
The vents are designed with wooden slats on the outside
and a grill so that they can even be left open at night in
the summer to cool the building down.
Ventilation – keeping air fresh and staying cool enough - WISE
Thermal mass can take some heat
out of the air but frequently you
need to do more. Many modern
buildings use air conditioning but
that uses a lot of energy.
In the lecture theatre there is a heirarchy of
cooling/ventilation systems.
First a thermostat turns the underfloor heating off.
Fresh air can flow from the lobby and up out
through vents in the lantern (stack ventilation).
Then a CO2 sensor can trigger air to be drawn with
a fan out through vents half way up the wall and
through a system that either recovers heat or
draws in cool air, depending on the weather.
Ventilation – keeping air fresh and staying cool enough - Y Senedd
. The roof cowl is
designed to rotate with
changes in wind
direction. This produces
a negative pressure on
the leeward side of the
cowl that allows warm air
to be drawn out of the
Siambr
Ventilation – keeping air fresh and staying cool enough – the
Passivhaus approach in Canolfan Hyddgen
Passivhaus buildings have very high and specific standards for airtightness and high
levels of insulation. A significant amount of the heat energy needed will come from
people in the building and the lights and equipment, so the architects need to know
exactly how the building will be used. If the temperature changes the automatic
controls will decrease or increase heating, increase ventilation etc.
Daylighting - light from the sun without glare
North facing windows
give you even light
without glare
St Lukes high clerestory
windows light up the
classrooms. Coloured film
has been added to
create atmosphere
WISE – the lecture theatre
can be daylit from a huge
sliding door and a circular roof
light that is closed with a ‘Moon
disc’ that rotates into place on
a rail.
Daylighting - light from the sun without glare – Y Senedd
The public open area has very
large areas of window giving
views over the Bay and
reinforcing the idea of an open
democracy
The lantern allows natural daylight into the
Siambr (Chamber where the Assembly
members sit). A conical mirror within the
lantern reflects additional daylight into the
Siambr and this can be lowered to control
daylight levels
Insulation and air tightness
Insulating materials all work
because they contain bubbles of
air. They vary in how much
thickness you need and how much
energy they take to make.
If gaps are left between
insulating materials it seriously
reduces the efficiency of the
system so ‘airtightness’ is
important.
It is easy to avaid gaps when
you use materials like Warmcel
and hemp lime which flow into
all the spaces.
Spraying 50cm of hemp/lime
into walls in WISE.
The spongy centre of the
hemp stems make a good
insulator when it is that thick
All these buildings use
insulating materials that are
low energy to produce
In the terrace floors
in WISE the insulation
is 25cm cork
St Lukes and Canolfan
Hyddgen use high
levels of recycled
newspaper (Warmcel)
and WISE has 45cm of
it in the roof
Renewable technologies – generating electricity
Canolfan Hyddgen
has 7kW
of PV cells. These will
generate about ¼ of
the building’s
electricity use
CAT put in an extra 7kW of
Photovoltaic cells attached to
WISE (added to an existing set
of 13kW). The 7kW should
produce 5300kWh a year.
PV cells are a very expensive way to
generate electricity in the British
climate.
The efficiency of the building
itself is much more important.
The WAG building in
Aberystwyth has a small
wind turbine but WAG
policy is also to buy green
electricity which will come
from much more efficient
large scale windfarms
Renewable technologies – producing heat
St Lukes, WISE
and the Senedd
have boilers that
burn wood chip or
wood pellets.
As WISE has ensuite study
bedrooms for people on
courses, it uses far more hot
water than the other
buildings so it has a 70m2
solar water heating system.
CAT is experimenting
with a large wood chip
combined-heat-andpower plant to provide
heat and electricity
for WISE
Managing energy – electricity use
Electrical devices use energy but they also give
off heat which can make a big difference in a
very well insulated building
All these buildings use low energy
lighting – LEDs and efficient
fluorescent tubes.
They also use sensors to turn them
off when they are not needed
LED lighting in WISE
Low energy computers were
specified in Canolfan Hyddgen
because such a precise system
could overheat but it’s
difficult to make sure that
users continue to use low
energy appliances.
Low energy fridge in staff
room at St Lukes
Low impact materials
St Lukes is an entirely timber
building, including the wall cladding
and the roof covering.
WISE contains a large amount of
timber.
Both have used different timbers
depending on the job that each has to
do.
Timber is low energy and also stores
carbon.
All of these buildings
have used materials that
are low impact, including
FSC timber, local
materials where that’s
possible, re-used
materials and, in most
cases, organic paints etc.
A compressed
earth block
wall in WISE
Rammed
earth
walls in
WISE
In use – understanding and managing the buildings
St Lukes has displays in every room describing
how the systems in the school work and the
pupils will be able to access real time
monitoring data of energy and water use on the
School’s computers
St Lukes also has a
cut-away display in
the lobby showing the
warmcell insulation
The manager at Canolfan Hyddgen makes sure
that users know how the system works and
how to manage it
WISE – the staff at CAT are very aware
of energy management issues.
St Lukes Display
Does the building smile at you?
WISE is very popular with its users –
“It’s a great working environment”
“I love taking round BTech
construction groups. They are always
wowed by it”.
“It’s a new building and it doesn’t
smell of plastic”
St Lukes The Head says “Children and staff
are keen to work; they love their
new learning environment”
A pupil says – “a happy building that
smiles at you”
Can the public come in?
All of these buildings want
the public to come in.
Canolfan Hyddgen is used by
the community for courses and
meetings
St Lukes Head: “It was important that we
created spaces and facilities that could be
used by the local families and groups in the
community and this, I believe, is one of the
key factors in our success”.
WISE is open to
visitors as often as
possible
The large lobby at the
Senedd is open to the
public all the time,
tours of the building
are run and there is a
viewing gallery for the
Assembly itself.
The WAG building in Aberystwyth
has a café and information desk in
its lobby for visitors.
The whole office is part of the
Welsh Assembly’s policy to spread
its staff around the country so
that they can be more in touch
with people.
What about transport?
The WAG building in Aberystwyth has been sited 10 minutes walk from
the bus and railway stations and a new bus stop was built right outside.
Staff are encouraged to cycle, use public transport and car share and
the car park was deliberately built much smaller than has been usual
with such buildings. Staff do not get a parking space unless they live
more than 3 miles away.
How successful are they?
Canolfan Hyddgen has achieved
an 85% reduction in heat energy
use compared with a standard
building and it has just won the
CIBSE award for New Build
Project of the Year.
Y Senedd building’s total energy
consumption dropped by 20%
between 2008/9 and 2009/10.
There were also significant
drops in travel for work and an
18% reduction in transport
emissions.
WISE is being thoroughly monitored
but it is too early to have results but
it was named best new building in
Britain in 2010 by the Daily Telegraph.
The building process was monitored in
great detail. Data was collected of all
the materials and energy used and
energy in use is being recorded as well.
St Lukes is also too new to
have detailed results but it
won the 2010 RIBA Sorrell
Foundation Schools Award.