Class Construction industry 10. a. Energy Sources. · Class 10. a. Learning for Self-Employment: Solar Energy. The amount of solar energy reaching the surface of the planet is so

Class 10. a.

Construction Industry Posters:

Learning for Self-Employment: Solar Energy. The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined. Sunlight has influenced building design since the beginning of architectural history..Advanced solar architecture and urban planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth. Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures are a result of increased absorption of the Solar light by urban materials such as asphalt and concrete, which have lower albedos and higher heat capacities than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and plant trees. Although difficult to quantify, the use of natural lighting also offers physiological and psychological benefits compared to artificial lighting. Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid, while standard grid electricity can be used to meet shortfalls. Net metering programs give household systems a credit for any electricity they deliver to the grid. This is often legally handled by 'rolling back' the meter whenever the home produces more electricity than it consumes. If the net electricity use is below zero, the utility is required to pay for the extra at the same rate as they charge consumers.] Other legal approaches involve the use of two meters, to measure electricity consumed vs. electricity produced. This is less common due to the increased installation cost of the second meter.

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Understanding Construction Industry Basics to enable Critical Thinking & Self-reliance.

Construction industry Energy Sources.

Elements of passive solar design, shown in a direct gain application.

Class 10. b.


Learning for Self-Employment: Solar Cell. When energy is added to pure silicon, in the form of heat for example, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons, called free carriers, then wander randomly around the crystalline lattice looking for another hole to fall into and carrying an electrical current. However, there are so few of them in pure silicon, that they aren't very useful.

But our impure silicon with phosphorous atoms mixed in is a different story. It takes a lot less energy to knock loose one of our "extra" phosphorous electrons because they aren't tied up in a bond with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping, and when doped with phosphorous, the resulting silicon is called N-type ("n" for negative) because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon.

The other part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type ("p" for positive) has free openings and carries the opposite (positive) charge.




Class Class 10. c.


Learning for Self-Employment: Solar Cell.

When light, in the form of photons, hits our solar cell, its energy breaks apart electron-hole pairs. Each photon with enough energy will normally free exactly one electron, resulting in a free hole as well. If this happens close enough to the electric field, or if free electron and free hole happen to wander into its range of influence, the field will send the electron to the N side and the hole to the P side. This causes further disruption of electrical neutrality, and if we provide an external current path, electrons will flow through the path to the P side to unite with holes that the electric field sent there, doing work for us along the way. The electron flow provides the current, and the cell's electric field causes a voltage. With both current and voltage, we have power, which is the product of the two.

Silicon happens to be a very shiny material, which can send photons bouncing away before they've done their job, so an antireflective coating is applied to reduce those losses. The final step is to install something that will protect the cell from the elements -- often a glass cover plate. PV modules are generally made by connecting several individual cells together to achieve useful levels of voltage and current, and putting them in a sturdy frame complete with positive and negative terminals.




Extraction of Silicon

Silica Sand mining.

Class 10. d.


Learning for Self-Employment: On-Grid Solar System.

A "grid-tie" solar system is the most common method of installing a residential solar power system. Grid-tie systems are connected to the main power grid and are designed to sell power back to the utility company. In an arrangement known widely as "net metering", homeowners get paid for the electricity they generate in excess of what they use. This means that a system that produces 115% of a homeowner's annual electricity needs, the electric utility will pay for the extra 15% that was produced by the system. Homeowners often not only completely eliminate their electric utility bill but they may actually realize a net profit. Net-metering works only on "grid-tie" solar or wind power systems. Because you must be connected to the utility grid, off-grid power systems are not compatible to net-metering programs. These systems can be designed offset any percentage of your kilowatt-hour utility usage.

How does an On-Grid system work?

An On-Grid electrical system is a system that generates electricity and is connected to the main power grid. These systems are typically based on renewable energy sources such as the sun or wind. Solar, or photovoltaic, or PV, grid-tie systems convert sunlight into electric current. Solar panels absorb photons of light from the sun, producing DC current electricity. Another system component, the grid tie inverter, converts this DC current into AC current which can then either be used by electric "loads" in the home or it can be directed onto the main power grid for a credit toward your monthly electric utility usage.

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Class 10. e.

Opportunities within construction sector.

1. Construction site labourer.

2. Construction site technician[electrical or plumbing work]

3. Construction site supervisor-keeping records of work in progress, instructing laborers and planning the laborer’s work to efficiency.

4. Construction plant operators: poker vibrator, concrete mixer, truck driver, crane operator, excavator operator

5. Building industry consultants: Architect, Quantity Surveyor, Mechanical engineer[Building services, electrical engineer[building services], structural engineer, civil engineer, town planner, land surveyors, Solar power engineer.

6. Hardware shop owner, timber mart owner, Electrical and Plumbing Hardware shop stockist.

7. Manufacturer of construction material e.g. paint, steel, machine cut quarry stone, roofing truss, doors, owner of ballast crusher.


Construction industry Opportunities.

Opportunities within construction sector.

8. Construction finance sector-banks-offering of mortgage to home owners, offer construction loans, insurance to construction project.

9. Real estate agent-buying and reselling land and buildings.

10. Furniture and interior design manufacture and sales.

11. Building & roads contractor.

12. Machinery and Equipment hire-hire of poker vibrators, concrete mixers, cranes,excavators, low loaders, dump trucks,graders.

13. Construction and Real Estate journalist.

14. Architectural, Survey, Engineering drawing printing services.

15. Architectural model making-manual or using 3D Animation software.


Documents

Class Construction industry 10. a. Energy Sources. · Class 10. a. Learning for Self-Employment: Solar Energy. The amount of solar energy reaching the surface of the planet is so