eco malaysia

8/8/2019 Eco Malaysia

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ECO MALAYSIA

stop killing the planetSurah al-a raf ayat 56 bermaksud .dan janganlah kamu berbuat KEROSAKAN

dibumi setelah diciptanya debgan baik. Berdoalah kepada tuhan dengan rasa takut dan

penuh harap, sesungguhnya rahmat Allah sangat dekat kepada orang yang berbuat

demikian


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HEAT ISLAND (GLOBAL WARMING ) "Urban Heat Island" (UHI) refers to the tendency for a city to remain warmer than its

surroundings. This effect is caused mostly by the lack of vegetation and soil moisture,

which would normally use much of the absorbed sunlight to evaporate water as partof photosynthesis (a process called "evapotranspiration"). Instead, the sunlight is

absorbed by manmade structures: roads, parking lots, and buildings. With little or no

water to evaporate, the sunlight's energy goes into raising the temperature of those

surfaces. After the sun sets, the city is so warm that it never cools down as much as

the countryside around it, and so retains the heat island effect all night long. There is

some evidence that the Urban Heat Island effect modifies the rainfall patternsaround cities, at least in the summertime.

The first

documentation on

heat island occurs in

1818 by Luke

Howards


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CAUSESCommon construction materials absorb and retain more of the suns heat. Most materials are

impermeable and watertightDark materials can reach up to 80 c

Less vegetation surface

Human produced heat

Slower wind

Air pollution

CAN CONTRIBUTE TO:Human discomfort

Health problems

Higher energy bills

Increased pollutionGlobal warming


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Five main causes of heat island.

1. Reduced evaporator

2. Increased heat storage

3. Increased net radiation

4. Reduced convection

5. Increased anthropogenic heat


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Characteristic contributing to heat

urban heat island.Causes EffectsLack of vegetation Reduces evaporation

Widespread used of impermeable

surfaces

Reduces evaporation

Increased thermal diffusivity of urban

material

Increases heat storage

Low solar reflectance of urban material Increases net radiation

Urban geometric that slow wind speeds Reduces convection

Increased levels of air pollution Increases net radiation


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Man-made Causes

Pollution:Burning fossil fuels is one thing that causes pollution. When fossil fuels are burned

they give off a green house gas called CO2. Also, mining coal and oil allows methane to

escape. How does it escape? Methane is naturally in the ground. When coal or oil is

mined you have to dig up the earth a little bit. When you dig up the fossil fuels you dig

up the methane as well letting it escape into the atmosphere.

Population:More people means more food, and more methods of transportation. That means

more methane because there will be more burning of fossil fuels, and more

agriculture. If you've been in a barn filled with animals and you smelled something

terrible, you were smelling methane. Another problem with the increasing population

is transportation. More people means more cars, and more cars means more

pollution. Since CO2 contributes to global warming, the increase in population makes

the problem worse because we breathe out CO2. Also, the trees that convert our CO2

to oxygen are being cut down. (trees are a very important part of our eco-system)


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MITIGATION

Trees and Vegetation Shade trees and smaller plants such as shrubs,

vines, grasses, and ground cover, help cool the

urban environment.


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How It Works Trees and vegetation help cool urban climates through shading and

evapotranspiration. Shading Leaves and branches reduce the amount of solar radiation that

reaches the area below the canopy of a tree or plant.

generally 10 to 30 percent of the suns energy reaches the area below a

tree, with the remainder being absorbed by leaves and used for

photosynthesis, and some being reflected back into the atmosphere. For example, a multi-month study measured maximum surface

temperature reductions ranging from 20 to 45F (11-25C) for walls and

roofs at two buildings. Another study examined the effects of vines on

wall temperatures and found reductions of up to 36F (20C). A third

study found that tree shading reduces the temperatures inside parked cars

by about 45F (25C).


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Tree canopies, such as the deciduous trees around this home in

Virginia, can block much of the sunlight from reaching the ground or

the building


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evapotranspiration.

Trees and vegetation absorb water through their roots and emit it through

their leavesthis movement of water is called transpiration.

Evaporation, the conversion of water from a liquid to a gas, also occurs

from the soil around vegetation and from trees and vegetation as they

intercept rainfall on leaves and other surfaces.


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Benefits

lower energy use,

reduced air pollution and greenhouse gas emissions

protection from harmful exposure to ultraviolet (UV) rays,

decreased storm water runoff, potential reduced pavement maintenanced


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Cool Roofs

Cool roofing refers to the use of highly reflective and emissive materials. Cool roofing can help address the problem of heat islands, which results in

part from the combined heat of numerous individual hot roofs in a city or

suburb. Cool roofing products are made of highly reflective and emissive

materials that can remain approximately 50 to 60F (28-33C) cooler than

traditional materials during peak

Traditional roof can create problems such as:

1. Hotter indoor

2. Reduced indoor comfort

3. More energy used for cooling

4. More money

5. More wear on cooling system


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Solar Energy

Solar energy is composed of ultraviolet (UV) rays, visible light, and infraredenergy, each reaching the Earth in different percentages: 5 percent of solar

energy is in the UV spectrum, including the type of rays responsible for

sunburn; 43 percent of solar energy is visible light, in colors ranging from

violet to red; and the remaining 52 percent of solar energy is infrared, felt as

heat.


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Solar Reflectance

Solar reflectance, or albedo, is the percentage of solar energy reflected by

a surface. Researchers have developed methods to determine solar

reflectance by measuring how well a material reflects energy at each solar

energy wavelength. Traditional roofing materials have low solar

reflectance of 5 to 15 percent, which means they absorb 85 to 95 percent

of the energy reaching them instead of reflecting the energy back out to

the atmosphere. The coolest roof materials have a high solar reflectance

of more than 65 percent, absorbing and transferring to the building 35

percent or less of the energy that reaches them


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Thermal Emittance

A materials thermal emittance determines how much heat it will radiate

per unit area at a given temperature, that is, how readily a surface givesup heat. When exposed to sunlight, a surface with high emittance will

reach thermal equilibrium at a lower temperature than a surface with low

emittance, because the high-emittance surface gives off its heat more

readily.


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Cool Roof Types

Cool RoofCoatings.

Coatings are surface treatments that are best applied to low-sloped roofsin good condition. They have the consistency of thick paint and contain

additives that improve their adhesion, durability, suppression of algae and

fungal growth, and ability to self-wash, or shed dirt under normal rainfall.

EPDM (ethylene propylene diene monomer), a synthetic rubber material,

with seams that must be glued or taped together. CSPE (chlorosulfonated polyethylene), a polymer material, with seams

that can be heat-welded together.

PVC (polyvinyl chloride) and TPO (thermoplastic olefins),


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Cool pavingCover large percentage of urban and suburban areas.

There is 2 way to make pavement cooler:

1. By increasing their solar reflectance

2. By increasing their ability to store and evaporate water.

Conventional pavements in the United States are impervious concrete*

and asphalt, which can reach peak summertime surface temperatures of

120150F (4867C).2

These surfaces can transfer heat downward to be stored in the pavement

subsurface, where it is re-released as heat at night. The warmer daytime

surface temperatures also can heat storm water as it runs off the

pavement into local waterways.


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TYPES OF COOL PAVING

1 asphalt cement concrete (ACC)

2 Portland cement concrete (PCC)


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Current

Future = global Warming

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