Transcript Energy in use ppt - Sustainable Design Award

Energy in use
Hot water 25%
Energy in use…is the energy used everyday
once the building is occupied.
Electricity
10%
Space
heating
60%
Cooking
7%
Energy is typically used in homes to:
Most energy,
60%, is used
for space
heating.
⌂ heat rooms
⌂ heat water
⌂ cook
⌂ power electrical appliances & lights
Where does energy come from?
50%
Energy to run buildings uses huge amounts of fuel.
Buildings are responsible for 50% of Europe's energy use
and housing produces 25 % of the UK’s carbon
emissions.
oil
gas
coal
We get our energy from primary
sources (e.g. crude oil) which is
converted (e.g. into electricity)
for use in our buildings.
renewable
e.g. wind, solar
ENERGY
heat, light & appliances
Choose your supply carefully
Different energy sources result in
very different CO2 emissions:
Source: http://www10.antenna.nl/wise/537/gl/graph2.gif
How can we reduce energy use?
As designers, we want to:
⌂ minimise demand for energy;
⌂ maximise the energy used from sustainable sources; and
⌂ minimise the amount we waste.
Typical sources of heat loss from a
house.
The Passiv Haus uses only passive energy gained
from the sun, from occupants’ body heat and
incidental heat radiating from household
appliances. Key design features include good
orientation, large areas of glazing, good draught
proofing and high levels of insulation.
Energy use depends on the user
Building occupants are critical to effective reduction in energy use.
What will help to make people become more efficient users?
How many times do you leave the light on,
leave the door open or TV on standby?
What would persuade you to change your
behaviour?
Can you design a guide for your building users
to maximise positive impacts on the
environment?
Explore some of the myths about energy use at
http://www.nef.org.uk/energyadvice/mythstruths.htm#answer1
See User Behaviour in Energy Efficient Homes
http://www.ukace.org/research/behaviour/User%20Behaviour%20%20Phase%202%20report%20v1.0.pdf
Don’t waste it – insulate it
It is a law of physics that heat will flow in a solid, liquid or gas or between them until the
temperature of each is equal. If it is cold outside then the warmth (energy) will try to
escape from a house until it is the same temperature as the ambient air temperature
outside. Insulation acts as a barrier to that heat flow. The bigger the difference in
temperature, the faster the rate of flow of heat.
Heat flows in a house
In summer we may want to
stop heat getting into a house
which may suggest different
design features and materials.
How can we stop heat flow?
⌂ Heat flows through different
materials at different rates –
some materials are better heat
conductors than others.
⌂ The denser the material, the Cork insulation
better it is for conducting heat,
allowing heat to flow through it
more quickly.
⌂ Bad heat conductors, e.g.
wool, are therefore good
insulators.
Rockwool insulation
http://www.nef.org.uk/energyadvice/insulation.htm
What’s best?
Good insulation can be achieved by materials:
⌂ that have a low density;
⌂ incorporate air pockets;
⌂ such as polyurethane (oil derivative),
expanded polystyrene, sheep’s wool, recycled
paper;
⌂ that provide any insulation – it’s always better
than none!
Sheep’s wool insulation
http://www.sheepwoolinsulation.ie/abtprods.htm
Warmcel insulation made
from recycled newspaper
It’s a matter of calculation
Heat transfer happens in 3 ways:
⌂ conduction;
⌂ convection;
⌂ radiation.
When heat passes out of a building all three methods of
transference are at work. For example, heat is conducted
through solid parts of a wall, radiated across cavities and
from the outside surface, and is also convected from the
outside surface by wind passing across that surface.
Definition of U-value:
heat flow (Watts)
through 1m2 of a
construction at 1
degree C temperature
difference between the
inside & the outside.
A measure, called the U-value, combines the
impact of all three methods of heat transfer
on the material or structure concerned. There
are standard tables and manufacturers’
specification for most materials. The impact
of combining different materials and building
designs can be calculated.
Golden rule:
the lower U-value , the better the insulation.
Achieving a balance
Draughts result in heat loss and are therefore unwelcome, but adequate ventilation is
essential. Ventilation is critical in achieving a feeling of freshness and comfort. Fumes,
smells, humidity and excess heat all call for natural or mechanical ventilation,
depending on the situation. Ventilation requirements are calculated in metres cubed
per person per hour, or air changes per hour.
http://www.theyellowhouse.org.uk/themes/ventil.html#v1
Designing buildings so that they have
very few draughts can save a lot of
energy by reducing the heat lost.
Effective draught exclusion depends on
good detailing of doors and windows.
At Bed Zed, the hoods on the
roof move around with the
wind creating a draft up the
“chimney” providing suction
to let warm moist air out.
Instead of using air conditioning, employing a
huge amount of energy, we can use the natural
‘stack effect’ to ventilate buildings. Warm air rises
naturally, it simply needs a path to follow.
If the air is just let out, it will take all the heat
with it. A heat recovery system can stop this
heat loss, by letting the heat from the air out
transfer to the air coming in..
Reducing energy use by design
Steps to minimise energy use and provide a healthy built environment:
⌂ minimise heat losses by insulating the building fabric;
⌂ provide good levels of ventilation to assure air quality;
⌂ minimise demand by using energy efficient lightbulbs and ‘A’ rated
appliances, think about external lighting too;
⌂ design space for clothes drying to reduce use of tumble driers;
⌂ install combined heat and power and/or use renewable energy sources
to heat space and water.
⌂ simple building plans (shape) result in less heat loss than complex
⌂
⌂
⌂
⌂
shapes;
ensure ample daylight provides natural internal lighting;
consider the location in terms of access to facilities &
transport
make best use of natural features of the site, sheltered
situations can reduce heat losses by as much as 20%;
orient the building and design areas of glazing to
maximise solar gain in winter and shade in summer;
Follow this link for
more in depth
consideration of land
use, siting &
orientation.
No energy…
• How important is access to
energy for human
development?
• 2 BILLION people worldwide
don’t have access to grid
electricity or commercial
energy supply
• Practical Action, a
development organisation, is
working to improve poor
people’s access to energy
• They also work to help people
use the energy sources they
can access more efficiently
www.practicalaction.org.uk and click on energy
Practical Action’s projects
Practical Action’s projects
provide
• energy to light homes
• energy to light schools
and hospitals
• energy to run small scale
businesses
Practical Action promotes
• micro-hydro systems
• biogas plants
• wind power systems
www.practicalaction.org.uk and click on energy
Harnessing the wind in Sri Lanka
• More than 70% of Sri Lankans live in
rural areas where there is no grid
electricity
• Weerasinghe, pictured, had to use
kerosene and an old car battery
• Kerosene lamps were used for
lighting and are notorious for
causing burns
• The battery cost more than eight
dollars a day, a fortune to him
• He can now generate light from his
own wind turbine. He says, “It’s
wonderful. Straight away there was
enough power to light a few light
bulbs. Now I can work longer and
my children can do their
homework.”
• Is a wind turbine a possibility in your
design?
www.practicalaction.org, go to energy, wind power
Improved cooking stoves
• Traditional cooking methods
use a three stone fire, which
wastes much heat and wood
• “Anagi” stoves, shown below
right, have helped cut down
use of firewood by one third
• They also improve the
efficiency, enabling two or
three utensils to be used from
the same fire
• They are cheap to make, use
local clays, and cut down
risks of burns.
• Have you chosen to use
energy efficient methods?
www.practicalaction.org, go to energy, improved stoves
In summary, wherever in the world…
www.sda-uk.org/toolsa.html
Further resources
There are links to other information throughout this presentation – look
for the house symbol to go to presentations that consider the issues in
more depth.
There are lots of web-based resources, some of which focus on energy
issues in building. They include:
www.sustainablehomes.co.uk
www.bre.co.uk/services/Energy.html
www.dti.gov.uk/energy
www.greenheat.uk.com
www.est.org.uk/bestpractice
www.thecarbontrust.co.uk
www.safety.odpm.gov.uk/bregs/brads.htm
www.savenergy.co.uk
www.actionenergy.org.uk