Energy Efficient Buildings

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25 Νοε 2013 (πριν από 3 χρόνια και 23 μέρες)

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Energy Efficient Buildings

Engr.
Mansoor
-
Ul
-
Hassan
Siddique


Assistant Director

Green building


Green building

(also known as
green
construction

or
sustainable building
)


Design and construction of energy
efficient and zero energy homes


Goal
is to design and build homes
that


reduce or eliminate your need for
energy,


Freeing
you from the grasp of big energy
companies
.


Take a look at some of the innovative ways
we have come up
with.


The Common Objective

Is that green buildings are designed to reduce
the overall impact of the built environment on
human health and the natural environment by:


Efficiently using energy, water, and other
resources


Protecting occupant health and improving
employee productivity


Reducing waste, pollution and environmental
degradation.


Reducing environmental impact


Green building practices aim to reduce the
environmental impact of buildings, and the very first
rule is, do not build in sprawl (In cluster).


No matter how much grass you put on your roof, no
matter how many energy
-
efficient windows, etc.,
you use, if you build in sprawl, you've just defeated
your purpose.


The International Energy Agency released a
publication that estimated that existing buildings are
responsible for more than 40% of the world’s total
primary energy consumption and for 24% of global
carbon dioxide emissions.

Affordable Zero Energy Homes


A few short years ago the notion of a zero
energy home was beyond the imagination of
most people
.


Technologies required
were
available.


But the
costs to do this was far beyond the
average homeowners budget
.


Today we can build a home that is not only efficient
but can produce all of the energy needed through
use of renewable energy, primarily the sun.


By combining design, methods, materials and
systems we have come up with affordable
approaches to building


energy free homes, today.




Today a zero energy home can be built for as
little as
(
Rs
. 1468.5
sq
/
ft
) or $165
sq
/
ft

.


Forget the
Granite Countertops
and chose a
solar hot water system
instead.


Goals of green building


The concept of sustainable development can be
traced to the energy (especially fossil oil) crisis
and the environment pollution concern in the
1970s.


There are a number of motives to building
green, including environmental, economic, and
social benefits.


However, modern sustainability initiatives call
for an integrated and synergistic design to both
new construction and in the retrofitting of an
existing structure.


Also known as
sustainable design
, this
approach integrates the building life
-
cycle
with each green practice employed with a
design
-
purpose to create a synergy amongst
the practices used.


Green building brings together a vast array
of practices and techniques to reduce and
ultimately eliminate the impacts of buildings
on the environment and human health.


It often emphasizes taking advantage of
renewable resources, e.g.,


Using Sunlight through Passive Solar,


Active Solar, and


Photovoltaic
T
echniques



Using plants and trees through green roofs,
rain gardens, and for reduction of rainwater
run
-
off.


While the practices, or technologies, employed in
green building are constantly evolving and may
differ from region to region, there are
fundamental principles that persist from which
the method is derived:


Siting and Structure Design Efficiency,


Energy Efficiency,


Water Efficiency,


Materials Efficiency,


Indoor Environmental Quality Enhancement,


Operations and Maintenance Optimization,


Waste and Toxics Reduction

There are several key steps in designing
sustainable buildings:


Reduce loads,


Optimize systems,


Generate on
-
site renewable energy.

Appliances


Modern energy
-
efficient appliances, such as:


Refrigerators,


Freezers,


Ovens,


Stoves,


Dishwashers,


And Clothes Washers And Dryers,


use significantly less energy than older
appliances.


Siting and structure design efficiency


The foundation of any construction project
is rooted in the concept and design stages.


The concept stage, in fact, is one of the
major steps in a project life cycle, as it has
the largest impact on cost and performance.


In designing environmentally optimal
buildings, the objective is to minimize the
total environmental impact associated with
all life
-
cycle stages of the building project.


However, building as a process is not as
streamlined as an industrial process, and
varies from one building to the other, never
repeating itself identically.


In addition, buildings are much more
complex products, composed of a multitude
of materials and components each
constituting various design variables to be
decided at the design stage.

Energy efficiency


Green buildings often include measures to
reduce energy consumption


both the:



Embodied Energy Required To Extract,


Process,


Transport And Install Building Materials


And Operating Energy To Provide Services Such
As Heating And Power For Equipment.

As high
-
performance buildings use:



Less Operating Energy,


Embodied Energy Has Assumed Much Greater
Importance


And May Make Up As Much As 30% Of The
Overall Life Cycle Energy Consumption.

To reduce operating energy use:



High
-
efficiency Windows


Insulation In Walls, Ceilings, And Floors


Increase the efficiency of the building
envelope,
(the barrier between conditioned
and unconditioned space).

Another strategy



Passive Solar Building
D
esign
, is often
implemented in
Low
-
energy Homes
.


Designers orient windows and walls and place
awnings, porches, and trees to shade windows
and roofs during the summer while maximizing
solar gain in the winter.


In addition,
effective window placement
(day
lighting) can provide more natural light and
lessen the need for electric lighting during the
day.

Reduce the environmental impact of
the building.


Solar water heating reduces energy costs.


Onsite generation of renewable energy
through:


Solar Power,


Wind Power,


Hydro Power,


Biomass

Water efficiency


To the maximum extent feasible, facilities
should increase their dependence on water
that is collected, used, purified, and reused
on
-
site.


Waste
-
water may be minimized by utilizing
water conserving fixtures such as ultra
-
low
flush toilets and low
-
flow shower heads.


Bidets help eliminate the use of toilet paper,
reducing sewer traffic and increasing
possibilities of re
-
using water on
-
site.


Point of use water treatment and heating
improves both water quality and energy
efficiency while reducing the amount of
water in circulation.

Waste reduction


Well
-
designed buildings also help reduce the amount
of waste generated by the occupants as well, by
providing on
-
site solutions such as compost bins to
reduce matter going to landfills.


To reduce the amount of wood that goes to landfill,
the CO
2

Neutral Alliance (a coalition of government,
NGOs and the forest industry) created the website
dontwastewood.com. The site includes a variety of
resources for regulators, municipalities, developers,
contractors, owner/operators and
individuals/homeowners looking for information on
wood recycling.


Thermal Envelope


A thermal envelope is everything about the
house that serves to shield the living space
from the outdoors.


It includes the wall and roof assemblies,
insulation, air/vapor retarders, windows, and
weather
-
stripping and caulking.



Wall and Roof Assemblies


Most builders use traditional Concrete frame
construction.


Concrete framing is a “Tie & Hold Technique”
construction technique that uses a potentially
renewable resource

wood


to provide a
structurally sound, long
-
lasting house.


With proper construction and attention to details,
the conventional wood
-
framed home can be very
energy efficient.


It is now even possible to purchase a sustainably
harvested wood.


And use instead of Concrete.

Optimum Value Engineering (OVE)


This method uses wood only where it is most
effective, thus reducing costly wood use and
saving space for insulation.


The amount of lumber has been determined
to be structurally sound through both
laboratory and field tests.


However, the builder must be familiar with
this type of construction to ensure a
structurally sound house.

Structural Insulated Panels (SIPs)


These sheets are generally made of plywood or


oriented
-
strand board (OSB) that is laminated
to foam board.


The foam may be 4 to 8 inches thick.


Because the SIP acts as both the framing and
the insulation, construction is much faster than
OVE or stick framing.


The quality of construction is often superior
because there are fewer places for workers to
make mistakes.

Insulating Concrete Forms (ICF).


Houses constructed in this manner consist of
two layers of extruded foam board (one inside
the house and one outside the house) that act
as the form for a steel
-
reinforced concrete
center.


It’s the fastest technique and least likely to
have construction mistakes.


Such buildings are also very strong and easily
exceed code requirements for areas prone to
tornadoes or hurricanes.

Passive Solar design with overhang
above the south facing windows

Weather
-
stripping and Caulking


You should seal air leaks everywhere in a home’s thermal
envelope to reduce energy loss.


Good air sealing
alone may reduce
utility costs by as much
as 50 percent when compared to other houses of the
same type and age.


You can accomplish most air sealing by using two
materials:


caulking and weather
-
stripping.


Caulking


can be used to seal areas of potential air leakage into or out
of a house.


Weather
-
stripping


can be used to seal gaps around windows and exterior doors.

Controlled Ventilation


Since an energy
-
efficient house is tightly
sealed, it needs to be ventilated in a
controlled manner.


Controlled, mechanical ventilation prevents
health risks from indoor air pollution,
promotes a more comfortable atmosphere,
and reduces air moisture infiltration, thus
reducing the likelihood of structural
damage.


Furnaces, water heaters, clothes dryers, and
bathroom and kitchen exhaust fans expel air
from the house, making it easier to
depressurize an airtight house if all else is
ignored. But natural
-
draft appliances may be
back
-
drafted by exhaust fans, which can lead
to a lethal buildup of toxic


Air leakage can occur in many place
throughout a home.

Heat recovery ventilation

Heating and Cooling Systems


Specifying the correct sizes for heating and
cooling systems in airtight, energy
-
efficient
homes can be tricky.


Rule
-
of
-
thumb sizing is often inaccurate,
resulting in wasteful operation.


Conscientious builders and heating, ventilation,
and air
-
conditioning contractors size heating
and cooling equipment based on careful
consideration of the thermal envelope
characteristics.


Generally, energy
-
efficient homes require relatively
small heating systems, typically less than 50,000
Btu/hour even for very cold climates.


Some require nothing more than sunshine as the
primary source of heat along with auxiliary heat from
radiant in
-
floor heating, a standard gas
-
fired water
heater, a small boiler, a furnace, or electric heat
pump.


Any common appliance that gives off “waste” heat
can also contribute significantly to the heating
requirements for such houses.


If an air conditioner is required, it’s often a
small unit and sufficient for all but the
warmest climates.


Sometimes only a large fan and the cooler
evening air are needed to make the house
comfortable.


The house is closed up in the morning and
stays cool until the next evening.


Improving Energy Efficiency through
Building Materials, Pakistan


PROJECT DATA



Project Name:
Building and Construction
Improvement Program Implementing
Organization:
Aga Khan Foundation


Pakistan (NGO)


Project Location:
Nathiagali

and
Gilgit

areas,
northern Pakistan




ENERGY OVERVIEW


Energy Resource:
biomass


Technology:
roof hatch window, fuel efficient stove,
water warming facility


Application:
cooking, heating Sector: residential,
commercial (construction sector)


Cost of technology
: $17
-
31 (roof hatch window ) ;
$10
-
$19 (fuel efficient stove ) ; $33 (water
-

warming
facility) Number Served: 62 entrepreneurs trained to
produce BACIP products; 7 businesses established to
sell BACIP products; 135 promotional models
installed; activities in 13 villages.

Technology


The technologies supported by the SGP project
include:


Fuel efficient stoves (FEW), which include a water
-
warming facility (WWF) that can be used while cooking
(reduces 50% energy needs)


Roof hatch windows (RHW), which allow more sunlight
in the home but reduce heat loss


Light roofs and efficient construction techniques which
use 60% less timber in construction, and due to their
thermal efficiency reduce up to 65% firewood needed to
heat homes in the
winter.These

techniques also help
reduce hazard risks during earthquakes.


Insulation and other thermally
-
efficient housing
construction techniques which reduce energy use
by up to 70%


Roof treatment techniques and the introduction of
stabilized mud blocks to improve the thermal
efficiency of houses in rural mountain environments



Technical descriptions of three techniques


the
wire
-
mesh knotting equipment, galvanized wire
-
mesh wall reinforcement, and the house planning
tool.


Environmental Benefits


Global:


The reduced use of biomass energy decreases carbon dioxide
emissions that contribute to climate change.


The project evaluation estimates that the use of fuel
-
efficient
stoves with water
-
warming facilities in 2,500 households (the
current estimate of project impact), would reduce fuel wood
consumption by 862,500 kg per month.


This is equivalent to 10 tons of fuel wood per year, and 30 tons
of carbon emissions avoided over a six
-
year product life.


Local:


Although no studies of this impact are available, the reduced
collection of fuel wood and other biomass should lessen
pressure on local forest ecosystems.

LESSONS LEARNED


Environmental Management


Barrier Removal


Scaling Up

Ideal Scenario