Solar Panels and Application of Solar Energy in Practical Daily Activities.

SOLAR PANELS

Solar panels or photovoltaic (PV) cells for electricity consist of solar cells (semiconductor material such as silicon).

It is a device that converts heat energy from the solar radiation(sunlight) directly into electricity using the photoelectric effect.

The photoelectric effect is the name given to the observation that when light is shone onto a piece of metal, a small current flows through the metal.

The light is giving its energy to electrons in the atoms of the metal and allowing them to move around, producing the current.

The basic solar cell typically produces only a small amount of power.

To produce more power, solar cells can be interconnected to form panels or modules.

PV systems are modular, depending on your electricity use. Every part of the system can be sealed to provide as much power as you want.

The process of generating electricity from a solar panel

Solar panels, also known as modules, contain photovoltaic cells made from silicon that transform incoming sunlight into electricity.
Solar photovoltaic cells consist of a positive and a negative film of silicon placed under a thin slice of glass.
As the photons of the sunlight beat down upon these cells, they knock the electrons off the silicon.
The negatively-charged free electrons are preferentially attracted to one side of the silicon cell, which creates an electric voltage that can be collected and channelled.
This current is gathered by wiring the individual solar panels together in series to form a solar photovoltaic array.
The electricity produced at this stage is DC (direct current) and must be converted to AC (alternating current) suitable for use in your home or business.

Solar Thermal Processes

In solar thermal processes, the sun’s energy is absorbed as heat by a receiver, which undergoes an increase in temperature, vaporization, or other heat-absorbing processes.

The most widely used solar energy technology is the solar thermal process.

It uses heat from the sun for water and space heating, cooking, water distillation, disinfection, and many more.

APPLICATION OF SOLAR ENERGY

Farms and ranches

Applications of solar energy in agriculture include timed planting cycles, growing crops, pumping water, drying crops, brooding chicks, and drying chicken manure.

Space and water heating

Livestock and dairy operations often have sustained air and water heating requirements.
Modern pig and poultry farms raise animals in enclosed buildings, where it is necessary to carefully control temperature and air quality to maximize the health and growth of the animals.
These facilities need to replace the indoor air regularly to remove moisture, toxic gases, odours, and dust. Heating this air, when necessary, requires large amounts of energy.
With proper planning and design, solar air or space heaters can be incorporated into farm buildings to preheat incoming fresh air.
Those systems can also induce or increase natural ventilation levels during hot weather months.
Solar water heating systems can provide low to medium temperature hot water for pen cleaning.
Commercial dairy farms use a large amount of energy to heat water to clean equipment, as well as to warm and stimulate cows’ udders.
Heating water and cooling milk can account for up to 40% of the energy used on a dairy farm.
A solar water heating system may be used to supply all or part of these hot water requirements.

Crop and grain drying

Using the sun to dry crops and grain is one of the oldest and most widely used applications of solar energy.
The simplest and least expensive technique is to allow crops to dry naturally in the field, or to spread grain and fruit out in the sun after harvesting.
The disadvantage of these methods is that the crop and grain can be damaged by birds, rodents, wind, rain, and contamination by wind-blown dust and dirt.

More sophisticated solar dryers do the following;

Protect grain and fruit
Reduce losses
Dry faster and more uniformly
Produce a better-quality product than open-air methods.
Greenhouse heating
Farms can also use energy to heat greenhouses.
Commercial greenhouses typically rely on the sun to supply their lighting needs.
They are usually not designed to use the sun for heating.
They rely on gas or oil heaters to maintain the temperatures necessary to grow plants in the colder months.
Solar greenhouses, however, are designed to use solar energy for both heating and lighting.
A solar greenhouse uses thermal mass to collect and store solar heat energy.
Its insulation retains this heat for use during the night and on cloudy days.
Various products range from double-panel to “cellular” glazing.
A solar greenhouse reduces the need for fossil fuels for heating.
A gas or oil heater may serve as a backup heater, or may increase carbon dioxide levels to induce higher plant growth.

Solar Lighting

The history of lighting is dominated by the use of natural light.

In the 20th century, artificial lighting became the main source of interior illumination, but daylighting techniques and hybrid solar lighting solutions are ways to reduce energy consumption.

Day Lighting

Daylighting systems collect and distribute sunlight to provide interior illumination.
This passive technology directly offsets energy use by replacing artificial lighting, and indirectly offsets non-solar energy use by reducing the need for air-conditioning. Sunlight has influenced building design since the beginning of architectural history.

Solar Thermal

Solar thermal technologies can be used for water heating, space heating, space cooling, and process heat generation.
Solar hot water systems use sunlight to heat water.
In low geographical latitudes (below 40 degrees Celsius), from 60 to 70% of the domestic hot water use with temperatures up to 60°C can be provided by solar heating systems.
It is also used mainly to heat swimming pools.

Heating, cooling, and ventilation

Solar heating, cooling, and ventilation technologies can be used to offset a portion of the energy needed.

Water Treatment

Solar water disinfection involves exposing water-filled plastic bottles to sunlight for several hours.
Exposure times vary depending on weather and climate, from a minimum of six hours to two days during fully overcast conditions.
It is recommended by the World Health Organization as a viable method for household water treatment and safe storage.
Over two million people in developing countries use this method for their daily drinking water.

Small-scale solar-powered sewerage treatment plant.

Solar distillation can be used to make saline or brackish water potable.

Electrical Generation

The solar panels concentrate sunlight from a field of heliostats on a central tower.
Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV) or indirectly using concentrated solar power (CSP).
CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam.
PV converts light into electric current using the photoelectric effect.

Solar energy can be converted to electricity in two ways:

Photovoltaic (PV) devices or “solar cells” change sunlight directly into electricity.
PV systems are often used in remote locations that are not connected to the electric grid.
They are also used to power watches, calculators, and lighted road signs.
Solar Power Plants indirectly generate electricity when the heat from solar thermal collectors is used to heat a fluid, which produces steam that is used to power a generator.

SOLAR VEHICLES

Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption.

SOLAR CHEMICAL

Solar chemical processes use solar energy to drive chemical reactions.
Those processes offset energy that would otherwise come from an alternate source and can convert solar energy into storage and transportable fuels.
Solar-induced chemical reactions can be divided into thermochemical or photochemical.

SOLAR COOKERS

Solar cookers use sunlight for cooking, drying, and pasteurization.
They can be grouped into three broad categories: cookers, panel cookers, and reflector cookers.
A basic box cooker consists of an insulated container with a transparent lid.
It can be used effectively with partially overcast skies, which could reach temperatures of 90 – 150°C.
Panel cookers use a reflective panel to direct sunlight into an insulated container and reach temperatures comparable to box cookers.
Reflector workers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container.
The solar bowl is a concentrating technology employed where a stationary spherical reflector focuses light along a line perpendicular to the sphere’s interior surface, and a computer control system moves the receiver to intersect this line.
Steam is produced in the receiver at temperatures reaching 150°C and then used for processing heat in the kitchen.

APPLICATION OF SOLAR ENERGY IN PRACTICAL DAILY ACTIVITIES

When we wash our clothes and spread them outside in the sun to dry, we are using the heat from the sunshine.
We have also seen farmers dry pepper, maize, cocoa, coffee, etc., in the sun. Our fishermen also spread fish in the sun on the beaches to dry.
We also use solar thermal energy through passive solar designs.
Windows or skylights in your home can be designed to face the Sun so that they let heat into the house, keeping you warmer in the cold.
It is common knowledge that if you leave a bucket of water in the sun in the morning, the water absorbs heat from the sunshine, and by noon or by 1 p.m., the water will become quite hot, which can be used for bathing and other activities.
In all these examples, the heat in the sunshine is being used.
In other words, we have always used solar energy.
It is not new to us.
We now hear more about solar energy because scientists have become interested in using this form of energy more efficiently than we have always done.
For example, today we have solar watches, solar bulbs, solar cars, solar cookers, solar dryers, solar heaters, and others.
All of these use solar energy.
We have learnt earlier about the use of solar energy and the technologies to tap the solar energy for efficient use.

In summary, the use of solar energy in daily activities includes the following:

Heating water for bathing
Drying clothes
Drying crops for preservation
Using solar cookers for cooking
Boiling eggs

Advantages of solar energy as an alternative source of energy

Conversion from sunlight to electricity is direct, so that bulky mechanical generator systems are unnecessary.
PV arrays can be installed quickly and in any size required or allowed.
The environmental impact is minimal, requiring no water for system cooling and generating no by-products.
Solar energy is free, and its supplies are unlimited.
Using solar energy produces no air or water pollution.

Disadvantages of solar energy as an alternative source of energy

The amount of sunlight that arrives at the Earth’s surface is not constant. It depends on location, time of day, time of year, and weather conditions.
Because the sun does not deliver that much energy to any one place at any one time, a large surface area is required to collect the energy at a useful rate.
Large solar thermal farms can harm desert ecosystems if not properly managed.
Using solar energy has some indirect impacts on the environment. For example, manufacturing the photovoltaic cells used to convert sunlight into electricity consumes silicon and produces some waste products.

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Solar Panels and Application of Solar Energy in Practical Daily Activities