Solar energy, wind energy, and biogas are important renewable energy sources with various applications. Solar energy can be harnessed using technologies like solar panels, photovoltaic cells, and concentrated solar power to generate electricity or heat water. Wind turbines convert kinetic wind energy to mechanical or electrical power. Biogas is produced through anaerobic digestion of organic waste and can be used as fuel for cooking or generating electricity. Proper management of greywater, blackwater, and solid waste is crucial to prevent environmental pollution and disease.

2. Q. Write the note on solar energy and its
application?
 Solar energy: Solar energy is radiant light and heat from the Sun that is harnessed using a
range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal
energy, solar architecture, molten salt power plants and artificial photosynthesis.
 It is an essential source of renewable energy, and its technologies are broadly characterized
as either passive solar or active solar depending on how they capture and distribute solar
energy or convert it into solar power.
 Active solar techniques include the use of photovoltaic systems, concentrated solar power,
and solar water heating to harness the energy.
 Passive solar techniques include orienting a building to the Sun, selecting materials with
favorable thermal mass or light-dispersing properties, and designing spaces that naturally
circulate air.
 The large magnitude of solar energy available makes it a highly appealing source of
electricity.

3.  Application:
 Energy from sun can be categorised in two ways: in the form of heat and light. We use the
solar energy every day in many different ways. When we hang laundry outside to dry in the
sun, we are using the solar heat to dry our clothes. Plants make their food in the presence of
sunlight. Animals and humans get food from plants. Fossil fuels are actually solar
energy stored millions and millions of years ago.
 There is variety of products that uses solar energy. These products are called solar devices
(or appliances) or solar thermal collectors. Solar thermal technologies uses the solar heat
energy to heat water or air for applications such as space heating, pool heating and water
heating for homes and businesses. Let us look at the applications of solar energy in
different sectors.
 Residential Application
 Use of solar energy for homes has number of advantages. The solar energy is used in
residential homes for heating the water with the help of solar heater. The photovoltaic cell
installed on the roof of the house collects the solar energy and is used to warm the water.
Solar energy can also be used to generate electricity. Batteries store energy captured in day
time and supply power throughout the day. The use of solar appliances is one of the best
ways to cut the expenditure on energy.

4.  Industrial Application
 Sun’s thermal energy is used in office, warehouse and industry to supply power. Solar
energy is used to power radio and TV stations. It is also used to supply power to
lighthouse and warning light for aircraft.
 Remote Application
 Solar energy can be used for power generation in remotely situated places like schools,
homes, clinics and buildings. Water pumps run on solar energy in remote areas. Large
scale desalination plant also use power generated from solar energy instead of
electricity.
 Transportation
 Solar energy is also used for public transportation such as trolleys, buses and light-
rails.
 Pool heating
 Solar heating system can be used to heat up water in pool during cold seasons.

5.  Photovoltaic Cells :
 Photovoltaics (PV) is the conversion of light into electricity using semiconducting
materials that exhibit the photovoltaic effect, a phenomenon studied
in physics, photochemistry, and electrochemistry.

 fig. The basic operation of a PV cell

6.  A photovoltaic (PV) cell is an energy harvesting technology, that converts solar energy into
useful electricity through a process called the photovoltaic effect.
 There are several different types of PV cells which all use semiconductors to interact with
incoming photons from the Sun in order to generate an electric current.
 A photovoltaic cell is comprised of many layers of materials, each with a specific purpose.
The most important layer of a photovoltaic cell is the specially treated semiconductor layer.
It is comprised of two distinct layers (p-type and n-type) and is what actually converts
the Sun's energy into useful electricity through a process called the photovoltaic effect .On
either side of the semiconductor is a layer of conducting material which "collects" the
electricity produced.
 The photovoltaic effect is a process that generates voltage or electric current in
a photovoltaic cell when it is exposed to sunlight. These solar cells are composed of two
different types of semiconductors— p-type and an n-type —that are joined together to
create a p-n junction.
 By joining these two types of semiconductors, an electric field is formed in the region of the
junction as electrons move to the positive p-side and holes move to the negative n-side. This
field causes negatively charged particles to move in one direction and positively charged
particles in the other direction.

7. A diagram showing the photovoltaic effect

8.  When light of a suitable wavelength is incident on these cells, energy from the
photon is transferred to an electron of the semiconducting material, causing it to
jump to a higher energy state known as the conduction band.
 In their excited state in the conduction band, these electrons are free to move
through the material, and it is this motion of the electron that creates an electric
current in the cell.

9. Q. Write the note on wind energy and its
application.
Wind energy: Wind energy is a form of solar energy.
 Wind energy (or wind power) describes the process by which wind is used to
generate electricity.
 Wind turbines convert the kinetic energy in the wind into mechanical power.
A generator can convert mechanical power into electricity.
 Mechanical power can also be utilized directly for specific tasks such as
pumping water.
 Wind power or wind energy is the use of wind to provide the mechanical
power through wind turbines to turn electric generators and traditionally to
do other work, like milling or pumping.
 Wind power is a sustainable and renewable energy, and has a much
smaller impact on the environment compared to burning fossil fuels.

10.  Application of wind energy :
 1. The wind energy is used to propel the sailboats in river and seas to transport men
and materials from one place to another.
 2. Wind energy is used to run pumps to draw water from the grounds through wind
mills.
 3. Wind energy has also been used to run flourmills to grind the grains like wheat and
corn into flour.
 4. Now-a-days wind energy is being used to generate electricity.
 5. A number of sports use wind energy as their source like Wind Surfing, Land Surfing,
Kite boarding
 Wind energy may be considered as the world’s fastest growing energy source.

11.  Speed of wind energy:
 Wind speed fluctuates, which has an impact on wind electricity generation capacity and
operating characteristics. In general, wind speeds are as follows:
1) 8 kph (2 m/s) minimum is required to start rotating most small wind turbines.
2) 12.6 kph (3.5 m/s) is the typical cut-in speed, when a small turbine starts generating
power.
3) 36–54 kph (10–15 m/s) produces maximum generation power.
4) At 90 kph (25 m/s) maximum, the turbine is stopped or braked (cut-out speed).
 Wind Speed is measured in km's or miles per hour using an anemometer. An
anemometer looks like a weather vane, but instead of measuring which direction the
wind is blowing with pointers, it has four cups so that it can more accurately measure
wind speed. Each cup is attached to the end of a horizontal arm, each of which is
mounted on a central axis, like spokes on a wheel.
 Wind speed generally increases with height above the earth's surface and is affected by
variations such as the roughness of the ground and the presence of buildings,
vegetation and other obstacles in the area.
 The wind power density is the number of watts of electrical energy produced per
square metre of air space (W/m²). This value is normally given at 10 m or 50 m above
the ground.

12.  The Daily Wind Cycle:
 Wind energy is created by the uneven heating of the
Earths' surface by the Sun. During the day, the air
above the land heats faster than air over water.
 This warm air over the land expands and rises, and
the cooler air, which is heavier takes its place,
creating wind.
 At night, the winds direction is reversed because the
air cools quicker over land than over water. This is
called at the Daily Wind Cycle.
Fig. Changing temperatures over land
and water makes air move, creating
wind.

14. Q. Write short note on water
conservation and water efficiency.
 Water conservation:
 Water conservation is the practice of using water efficiently to reduce
unnecessary water usage.
 According to Fresh Water Watch, water conservation is important because
fresh clean water is a limited resource, as well as a costly one.
 As a homeowner, you’re probably already well aware of the financial costs of
inefficient water use. Conservation of this natural resource is critical for the
environment and our wallets.

15.  10 tips for saving water around the home
1. Put a brick in your toilet’s water tank.
2. Use the right amount of water for each load of laundry
3. Pick your washing machine wisely
4. Water plants wisely.
5. Install a low-flow showerhead.
6. Check for and repair leaks.
7. Use a dishwasher.
8. Turn off the water. Teach your whole household to turn off the faucet while brushing teeth
or shaving. Every little bit of water conservation helps!
9. Defrost food in the fridge.
10. Manage outdoor water use

16.  WHY CONSERVE WATER?
 1. It is a resource that is a benefit to everyone.
 2. To save money. Lower consumption means lower water bills.
 3. To keep rates low. Maximizing current water supplies helps defer the need to
develop new, more expensive sources of water.
 4. To prepare for a drought. Many areas of the country have experienced drought
conditions in the past few years. Water conservation helps prepare for these worst
of times.
 5. To comply with regulations. Many states and local regulators have established
efficient water use regulations.

17.  Water efficiency :
 Water efficiency is reducing water wastage by measuring the amount of water
required for a particular purpose and the amount of water used or delivered.
 Water efficiency differs from water conservation in that it focuses on reducing waste,
not restricting use. (Wikipedia)
 Definition: Water efficiency is the smart use of our water resources through water-
saving technologies and simple steps we can all take around the house.
 Using water efficiently will help ensure reliable water supplies today and for future
generations. (EPA-US)
 The terms water efficiency and water conservation are often used interchangeably.
 Water efficiency is the accomplishment of a function, task, process, or result with the
minimal amount of water feasible. (e.g. toilet flushing or showering) (CWCB

18. # ways to increase water efficiency.
1. Decreasing run-off losses: Contour cultivation, Terrace farming, Conservation-bench
terracing, Water spreading, Chemical wetting agents (Surfactants)
2. Reducing evaporation losses
3. Storing water in soil
4. Reducing irrigation losses
5. Reuse of water
6. Preventing wastage of water
7. Increasing block pricing
TWO TYPES OF PRACTICES
1. Engineering practices: practices based on modifications in plumbing, fixtures, or water
supply operating procedures.
2. Behavioral practices: practices based on changing water use habits.

19.  • Metering
 • Leak detection
 • Auditing water
 • Reduction in pressure
 • Recycle
 • Reuse
 • Dual flush
 • RWH
 • XERISCAPE LANDSCAPE

21. Q. What is the importance of grey water, black water, solid waste
management. Elaborate aftermath in handled inappropriately ?
 Grey water or sullage is all the wastewater generated in households or office
buildings from streams without fecal contamination, i.e. all streams except for the
wastewater from toilets.
 Sources of grey water include sinks, showers, baths, washing machines or
dishwashers.
 As grey water contains fewer pathogens than domestic wastewater, it is generally
safer to handle and easier to treat and reuse onsite for toilet flushing, landscape or
crop irrigation, and other non-potable uses.
 The application of grey water reuse in urban water systems provides substantial
benefits for both the water supply subsystem by reducing the demand for fresh clean
water and for the wastewater subsystems by reducing the amount of wastewater
required to be conveyed and treated.
 Treated grey water has many uses, for example, toilet flushing or irrigation.

22.  Treated grey water can be used to irrigate both food and non food producing plants.
 The nutrients in the grey water (such as phosphorus and nitrogen) provide an
excellent food source for these plants.
 Two major benefits of grey water use are:
1. Reducing the need for fresh water. Saving on fresh water use can significantly reduce
household water bills, but also has a broader community benefit in reducing demands
on public water supply.
2. Reducing the amount of wastewater entering sewers or on-site treatment systems.
Again, this can benefit the individual household, but also the broader community.


23.  Blackwater in a sanitation context denotes wastewater from toilets, which likely
contains pathogens.
 Blackwater can contain feces, urine, water and toilet paper from flush toilets.
 Blackwater is distinguished from grey water, which comes from sinks, baths, washing
machines, and other kitchen appliances apart from toilets.
 Greywater results from washing food, clothing, dishes, as well as from showering or
bathing.
 Blackwater and greywater are separated in "ecological buildings", such as autonomous
buildings. Recreational vehicles often have separate holding tanks for greywater from
showers and sinks, and blackwater from the toilet.
 Definition: Blackwater is the mixture of urine, feces and flushwater along with anal
cleansing water (if water is used for cleansing) and/or dry cleansing materials. Blackwater
contains the pathogens of faeces and the nutrients of urine that are diluted in the flushwater.

24. Solid-waste management
 Solid-waste management, the collecting, treating, and disposing of solid material
that is discarded because it has served its purpose or is no longer useful.
 Improper disposal of municipal solid waste can create unsanitary conditions, and
these conditions in turn can lead to pollution of the environment and to outbreaks of
vector-borne disease—that is, diseases spread by rodents and insects.
 The tasks of solid-waste management present complex technical challenges.
 They also pose a wide variety of administrative, economic, and social problems that
must be managed and solved.

25. Syllabus
Appropriate Technologies / Approaches for:
 A) Water conservation / efficiency.
 B) Sanitation (Grey water, black water management, SWM)
 C) Treatments.
 D) Biogas.
 E) Composting.
 F) Solar energy and its applicability through panels, photovoltaic cells etc.
 G) Use of ―LED, CFL, Fresnel Lens‖ etc.
 H) Wind energy and its use.
 I) Orientation aspects in site planning to achieve maximum daylight and natural ventilation.

26. Biogas
 Biogas is the mixture of gases produced by the breakdown of organic matter in the absence
of oxygen (anaerobically), primarily consisting of methane and carbon dioxide.
 Biogas can be produced from raw materials such as agricultural waste, manure, municipal
waste, plant material, sewage, green waste or food waste.
 Biogas is a renewable energy source. In India, it is also known as "Gobar Gas".
 Biogas is produced by anaerobic digestion with methanogen or anaerobic organisms, which
digest material inside a closed system, or fermentation of biodegradable materials.
 This closed system is called an anaerobic digester, biodigester or a bioreactor.
 Biogas is primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts
of hydrogen sulfide (H2S), moisture and siloxanes.
 The gases methane, hydrogen, and carbon monoxide (CO) can be combusted or oxidized
with oxygen.
 This energy release allows biogas to be used as a fuel; it can be used for any heating
purpose, such as cooking.
 It can also be used in a gas engine to convert the energy in the gas into electricity and heat

27.  Biogas can be compressed after removal of Carbon dioxide, the same way
as natural gas is compressed to CNG, and used to power motor vehicles.
 Biogas is considered to be a renewable resource because its production-and-
use cycle is continuous, and it generates no net carbon dioxide.
 As the organic material grows, it is converted and used. It then regrows in a
continually repeating cycle.
 From a carbon perspective, as much carbon dioxide is absorbed from the
atmosphere in the growth of the primary bio-resource as is released, when the
material is ultimately converted to energy.

30. Use of ―LED, CFL, Fresnel Lens‖ etc.
 LED :
 1. LED Light Lifespan:
 Easily the most significant advantage of LEDs when compared to traditional lighting solutions
is the long lifespan. The average LED lasts 50,000 operating hours to 100,000 operating hours
or more.
 2. LED Energy Efficiency:
 LEDs generally consume very low amounts of power.
 3. Improved Safety with LEDs:
 LEDs emit almost no forward heat while traditional bulbs like incandescents convert more
than 90% of the total energy used to power them directly into heat. That means only 10% of
the energy powering incandescent lights is actually used for light.

31.  4. LED Lights are Physically Small:
 The actual LED device is extremely small. Small power devices can be less than a tenth
of a single mm2 while larger power devices can still be as small as a mm2.
 5. LEDs Have Great Color Rendering Index (CRI):
 LEDs generally have very high (good) ratings when it comes to CRI.
 6. LEDs Generate Directional Emissions:
 LED technology emits light for only 180 degrees. Every other type of light emits light
360 degrees around the source.
 7. LEDs Have Tremendous Design Flexibility:
 Because LEDs are so small they can be used in virtually any application you can think
of.
 8. LEDs are Solid State Lights (SSLs):
 LEDs are solid state lights. This means that the traditional glass bulb surrounding the
light is entirely unnecessary.
 9. LED Dimming Capability:
 LEDs are able to operate at virtually any percentage of their rated power (0 to 100%).

32.  10. LEDs Provide Instantaneous Turn On and Do Not Have Issues with Frequent
Switching:
 LEDs turn on and off instantaneously. There is no warm-up period like in the case of metal
halide lamps. Additionally, frequent switching doesn’t cause degradation in the device.
 11. LED Lights are Environmentally Safe:
 LEDs do not have the environmental issues common to traditional lighting solutions
like fluorescent or mercury vapor lights.
 12. LEDs Produce Virtually Zero UV Emissions:
 LEDs emit the vast majority of their energy in the visible spectrum, a small amount in the
infrared spectrum, and virtually none in the ultraviolet portion of the spectrum.
 13. LEDs Operate on Very Low Voltage:
 In many cases LEDs operate on very low voltages.
 14. LEDs Operate Well in Cold and Hot Temperatures:
 LEDs work well in a wide range of operating temperatures without significant degradation.
 15. Correlated Color Temperature (CCT):
 LEDs are available in a wide range of correlated color temperature (CCT) values.

33. Uses of led
 High power arena lights, stadium light;
 Backyard lighting;
 Warehouse & construction lighting;
 Parking Lot lighting;
 Golf lights;
 Airport lights;
 Stage (RGB) lights.
 Led panels are very good for kitchens, corridors , etc. We installed one in the
kitchen, it make very cozy and beautiful light.
 Led tapes are very attractive - they use them even over the sport shoes - as
shoe lace - to light in the disco club :)
 Led controllers
 Led diodes
 Led indicators

34. CFL
 Compact fluorescent lamps (CFL bulbs) are a twist
on traditional fluorescent technology.
 Created as a more energy-efficient option for conventional
incandescent applications,
 CFLs screw into a medium base socket and utilize a spiral
design – as opposed to a long tube – making it "compact."
 Many CFLs also have an integrated ballast, unlike traditional
fluorescent tubes.
 Definition: A compact fluorescent lamp (CFL), also
called compact fluorescent light, energy-saving
light and compact fluorescent tube, is a fluorescent
lamp designed to replace an incandescent light bulb; some
types fit into light fixtures designed for incandescent bulbs.

35. Uses of CFL
 1. Recessed cans
 Recessed cans are used in both hospitality and residential setting
 2. Concealed fixtures
 People typically don’t like the way CFLs look, so to mitigate this obstacle,
many property managers use CFLs in fixtures that completely conceal the light
bulb from our eyes. A lot of older apartment complexes will have CFLs in the
whole apartment.

37. Composting
 Composting is the biological decomposition of organic waste such as food or
plant material by bacteria, fungi, worms and other organisms under
controlled aerobic (occurring in the presence of oxygen) conditions. The end
result of composting is an accumulation of partially decayed organic matter
called humus. Composting with worms, also known as vermiculture, results in
nutrient-loaded worm castings.
 Composting Methods
 Traditional backyard composting is typically achieved by:
 1. Open air composting (hot composting)
 2 Direct Composting (in-ground composting)

38.  More Recent methods of composting are:
 3 Tumbler Composting (A form of hot composting)
 4 Worm Farm Composting (Vermicomposting)
 5 EMO Composting (Bacteria composting)
 6 Combination Composting (Compot Composting)
 7 Commercial Composting
 8 Mechanical Composting

39.  1. Open Air Composting
 Open Air Composting is traditionally a pile of green and brown matter in your
backyard.
 More often than not it is a bay constructed of anything you can get your hands on that
is cheap and easy to put together.
 Or you might have a couple of bins upturned sitting on the ground like the Gedye bin
you can buy in a shop.
 Wire cages are also used inlaid with piping around the edges to hold water and
capture heat.
 This can then be used for hot water systems in sustainability situations.
 Open Air Composting is generally considered to be a Hot Composting method. Some
people often call it a Cold Composting when smaller quantities of waste are used
because it does not build up the same amount of heat.
 To me, Cold Composting still produces heat and therefore is not technically cold
composting.
 Perhaps one could call it Warm Composting as the only way you could completely
cold compost something is to let it rot in the fridge. And we all know that smell in the
fridge.

40.  2. Direct Composting
 Direct Compost is simply digging a hole or trench in the ground and burying your
scraps.
 It is also probably the oldest and most effective method of composting, but like all
other methods of composting it too has its limitations. The main one being that it
takes a long time to decompose unless you chop everything up.
 You can only bury fruit and veg or you run the risk of it being dug up by all sorts of
garden critters from birds to vermin. And you have to keep digging holes.
 It does, however, produce an abundance of worms that then help to nourish your
garden and improve your soil.