How many types of adverbs are there?

There are several types of adverb:

• Adverb of manner 
• Adverb of place 
• Adverb of time 
• Adverb of frequency 
• Adverb of degree

There are different places where you can put the adverb.

ADVERBS OF MANNER - these answer the question how?

This adverb usually comes after the direct object or if there is no direct object, after the verb:

She speaks Italian beautifully.
He works well.
You must drive your car carefully. 
Eat quietly.

ADVERBS OF PLACE - these answer the question where?

This adverb usually comes after the object, otherwise after the verb:
We saw you there. 
We were sitting here. 
We looked everywhere.
Note: somewhere, anywhere, follow the same rules as some and any:
Have you seen my glasses anywhere? 
I'm sure I left them somewhere. 
I can't find them anywhere.

ADVERBS OF TIME - these answer the question when?

This adverb usually comes either at the very beginning of the sentence or at the end.
Afterwards we decided to go by car. I've done that journey before.
Note: yet and still - yet should be placed at the end of the sentence.
Still should be placed before the verb, except with the verb 'to be' when it comes after.
We haven't started yet. 
He still wears old-fashioned clothes. 
She is still a student.
Compare these two sentences:
The train still hasn't arrived. 
The train hasn't arrived yet.

ADVERBS OF FREQUENCY - these answer the question how many times?

This adverb comes after the verb 'to be':
She is always honest.
Comes before simple tenses of all other verbs:
They sometimes spend the whole of Saturday fishing.
Comes after the first auxiliary in a tense consisting of more than one verb:
I have often wondered how they did that. 
I can sometimes go without food for days.
Note: with 'used to' and 'have' the frequency adverb is usually placed in front:
We always used to look forward to the school holidays. 
He never has any trouble with his old car.

ADVERBS OF DEGREE - these answer the question to what extent?

This adverb can modify an adverb or an adjective and comes before the word it modifies:
The bottle is almost full, nearly empty. 
They should be able to pass their exams quite easily.
The following adverbs of degree can also modify verbs: almost, nearly, quite, hardly, scarcely, barely, just.
They follow the same pattern as frequency adverbs in terms of where they are placed:
I quite understand. 
We had almost reached the hut when the rain started. 
I am just beginning a new course.

INVERSION

If you begin a sentence with one of the following, the normal word order changes - the verb comes first followed by the subject:
never, seldom, scarcely ..... when, no sooner ..... than, nowhere, in no circumstances, on no account, only then, not only.

Seldom has one century seen so many changes. 
No sooner did we hear the results when there was a knock at the door.
Never would I be persuaded to buy a secondhand car.
Usual word order with different adverbs: MANNER PLACE TIME
She sang beautifully in the concert hall last night.

Solar Energy – Nature and Composition

Sun is the main source of energy on the Earth. Life sustains on the Earth because of electromagnetic radiations and without the Sun, the Earth would have 270 degree Celsius of equilibrium temperature. The Earth emits an equal amount of energy as it receives from the space, so there is a heat balance on the Earth. The Sun pours a huge quantity of electromagnetic energy on it and everything on the Sun is the source of these radiations. The Sun emits over a wide range of electromagnetic radiations. The incident solar energy, mainly, is in the visible part of the solar spectrum, while the key part of the radiation lies in the infrared region.

In eight minutes the radiation emitted from the Sun gets to the Earth. The ray which lightens up the surface of the Earth is the visible light, also known as white light, which is the continuous mixture of colors. This light when passed through the prism disperses into a band of seven colors. The energetic part of the spectrum is the ultraviolet radiation, which is undetectable having shorter wavelengths compared to white light. Those of ultraviolet radiations having extremely shorter wavelengths are filtered in the outer atmosphere by the ozone layer.

Thermal radiations, as they are referred to, are the invisible infrared radiations having longer wavelengths compared to those of white light. Mostly, the incoming infrared rays are filtered by the atmosphere of the Earth containing water vapors. The opacity of the atmosphere, chiefly, is responsible for maintain the warmth of the Earth, although the surface of the Earth is rather transparent to the longer wavelengths in the infrared region.

Besides optical radiations from the Sun, solar energy spectrum contains radio and X-rays also. Hotter bodies emit a larger wavelength of spectrum. Intense radio waves have been observed over the Sun's surface at 330 MHz having wavelength of about one meter. The studies of wavelength in the X-rays component of the electromagnetic spectrum are made by specially designed sensitive imaging techniques.

Solar Energy – Effects on Health

Energy from the Sun is main source of energy on the Earth from the time immemorial. Plants use it in the synthesis of the food in the process called photoynthesis. Animals, indirectly, consume this energy in their food. Consumption of animals and plants on domestic level further enhanced human access to it. The human body synthesises vitamin D from solar radiation particulally from the UVB band of ultraviolet light, and excessive isolation from the sun can result in its deficiency lest ample quantity of it is taken in diet or in the form of supplements.

Expousre to solar radiations in excess has bees associates with various types of skin cancers resulting from ultraviolet portion of radiations from sun light or sun lamps. Mild to severe inflammations effects on skin can cause sunburns which can be avoided by the use of suitable sunscreen creams, lotions or by timely making of melanocytes with added exposure to the Sun. Early ageing is yet another damaging impact of ultraviolet exposure, also known to be as skin photo-damaging while having less treatable cosmetic effects. Such health hazard associated with skin are more concerning to the people in general, which have its basis from the fact that 10% depletion in the ozone layer could cause 25% rise in skin cancer.

On the other hand, an isolation from radiations from the Sun is hypothised to be the premier cause of a serious form of the winter blues, seasonal affective disorder (SAD). However, its symptoms are more to be found in the localities far from the tropical regions. Apart from druds' prescriptions, its treatment, mostly involves replcaing the Sun light with sun lamps which are tuned to particular visible (not ultraviolet) wavelengths of light or ful spectrum bulbs.

Recent studies have been made which concludes increased risks of multiple sclerosis later in a person's life is the aftermath of his increased exposure to solar radiations in his early life.

Solar Energy – Cultural Aspects

People, particularly, while reading from white paper upon which the sun is directly shining usually find direct light from the Sun to be much intense for comfort. Certainly, Looking directly straight towards the sun can cause long term eye hazards. Many people wear sunglasses to compensate for the intensity of the solar radiations. Visors are employed in caps and helments to block the sunlight when it is at low angle from direct vision.

People generally avoid the shade and prefer sunny days in colder regions while in the hotter regions it is the other way round, where people stay in the interiors during mid-day hours and avoid outdoor activities. They seek shade by trees, buildings, etc., in case, they visit outside. Radiations from the Sun are usually hindered to enter the interiors with the use of walls,, shutters, curtains, blinders, blinders.

People leisurely sitting or lying in direct sunlight taking sunbath, is a popular leisure activity. Usually people sitting in sunshine and taking sunbath in comfortable localities having sufficient radiations from the Sun. Common sunbathing areas include beaches, open air swimming pools, parks, side-walk cafés, etc. Ideally, sunbathers wear limited attire or remain simply nude. Sunbed is an another substitute that produces ultraviolet band of light spectrum, and is used in interiors, as it is independent of weather conditions and the intensity of sunshine.

In the outdoors, during vacations or holidays, people with lighter skin tones, namely of pale and brownish complexions take sunbath to darken theie skin color, also known as sun tan, which in some regions is regarded as beautiful, and is considered healthy activity. To obtain an even or a uniform sun tan nude sunbathing is preferred.

Dark pigments inside the skin, also known as melanocytes, on increasing their number helps achieving darkish complexion. Generally, on increased exposure to the ultraviolet radiations, it is an auto reactionary system of the body from the Sun and from artificial sun lamps. Hence, its not permanent and disappears gradually when one remain isolated from the light sources from longer periods of time.

Solar Energy – Energy Independent United States

Energy independence refers to the technology development and the shift in the energy policy thereby getting to the level of self sufficiency in the energy demands. The objective of energy independence is supposed to be energy resilience which goes together with flexibility, and it is echoed in important market ideas like finding alternatives. This can be achieved by generating an equal amount of energy as per needed. Presently, the United States is 70% independent in her energy. Energy independence is advocated by those who aim at an unaffected United States from the emerging disruptions in the energy supplies globally, and to check dependence for her energy supplies over the unstable political regions.

Energy independence has largely been associated with oil, being the major source of energy consumed in transport and electricity. Forty percent of the oil consumed in the United States is extracted locally. The United States has to rely on imported oil, apart from being the third major producer of oil in the world. Major of the imports are made from Canada and 19% of it comes from the Middle East. All these reservoirs are limited and expected to finish sooner considering growing energy demands. Globally, this demand is expected to rise up to 60% in next two decades.

Oil supply disruption, as was observer in the oil crisis in the year 1973 and the energy crisis in the year 1979 can only be averted by shifting to the alternate and renewable energy sources. Solar energy, alone has the capability of taking over all the United States energy demands in particular and the world in general, if harnessed in a proper way.

Renewable energy resources can be very incompetent, like the case of corn based bio-fuels, requiring substantial government financial backing and also huge quantity of water and other chemicals to produce, and causes considerable pollution in the air on combustion. Other renewable energy source like wind is costly and inconsistent, and lack the system and skill needed to suitably accumulate the energy they harness. America need more time to build up substitute energy sources, and that by using modern expertise, the effects on the environment would be the least.

Solar Energy – Consumption in the United States

Developing alternatives to non-renewable resources and mounting concerns about environmental changes has made path for the utilisation of other energy sources like solar energy. A promising solution to this energy demand is the making of solar power stations in areas like deserts and agricultural fields. Growing energy demands of electricity in the commercial hubs of Las Vegas, Las Angeles, and the Phoenix is met using solar thermal energy in the United States alone. Lacking molten salt technology solar power plant, Nevada Solar One, became operational in 2007 providing 64 megawatts of electricity.

Globally, more countries are planning, constucting and converting to solar energy as in Australia, North Africa, and Spain. Andasol 1, the solar power plant in the southern part of Spain, became operational in last November and providing 50 megawatts of electricity yearly meeting the needs of 50-60 thousand homes. Andasol 2 will soon start generation in the late summer whereas Andasol 3 is under construction. The copmletion of Andasol solar power project is determined at meeting the energy demands of 150 thousand households.

Stunning claims of the solar thermal energy are observed. Scientists and researchers estimates that a new infrastructure of high voltage, direct current transkission lines if built over less than one percent of world's deserts could generate enough electricity to meet the energy demands in the world. Amazingly enough is the claim that 16,000 squares kilometers solar panel could meet all of the Europe's energy demands.

Solar thermal energy projects experienced a boom in the late 1970s and in the early 1980s. With the lack of governmental sponsoring it came to standstill alongwith the reduction in the fossil fuel prices. Of the renewable energy produced in the United States, presently, electricity generate from the Sun is contributing only one percent, and accounted all together provide only seven percent of the United States power demands. According to Energy Information Administration, in 2007, about 612,000 megawatts of power was generated from the Sun. About 3,100 megawatts fo solar power thermal station are in planing to be functional by 2012, and is calculated to touch 6,400 megawatts in three years worldover.

Solar Energy – Modes to Capture

Sun, apart from being at distance of more than 150 kilometers away, is incredibly powerful. It has been used for cooking food and for drying clothes for many years, but just recently have we succeeded in employing it to produce electricity. Sun radiates a lot of energy in the surrounding universe, only a minor part of it is received on the Earth. Even then, this portion of it is sufficient to efficiently meet all the power needs of ours. As a matter of fact, energy coming to the Earth is so large in quantity, which if only a minute's radiations are captured properly, can fulfill our energy demands.

Mainly, there are three means to harness the solar radiations. Firstly, using photovoltaic panels, which if installed in sunny climate can ably lighten up a 100W bulb with only one square meter of solar cell. Originally, it was developed to generate electricity for satellites but now it is in our daily usage as in solar powered electronic devices like calculators. Secondly it is used in water heating with the energy absorbed from the Sun. Here heat energy coming from the Sun is benefited from to heat up water kept in glass panels on the roof tops. In the areas like California and Australia where the Sun shines in major part of the year, it is valuable and becoming likely important in the United Kingdom also. Consequently, mush of energy required to heat water is saved which was previously accomplished using gas or electricity.

Water is circulated in pipes which are painted in black. As soon as the Sun shines on them, the get heated up. The water from below is pushed in and using the principle of convection, hot water rises up and obtained from the top. It is favorable in internal heating replacing central heating central heating system and reducing fuel bills.

Thirdly, it is used to produce high temperature in a small region, employing mirrors and lenses which concentrate the radiations coming from the Sun. One such device is being installed and used specifically for scientific purposes at Odeillo in France. Using it a temperature of 3,000 degree Celsius can be attained.

Solar Energy – Energy from the Sun

Sun, since time immemorial, has been the only source of energy in our part of the universe. Energy from the Sun, for billions and billions of years, has been received by the Earth. This energy coming to the Earth in the form of rays is known as solar radiations.

Radiations from the Sun can be transformed into other forms of energy like into heat energy, electrical energy, etc. The British astronomer John Herschel, in the year 1830, was in an expedition through Africa. During his voyage he employed a device that used to collect heat of the absorbed light from the Sun with the help of a device called solar thermal collector box. In the present world it is used for varied purposes in different fields of life.

Conversion of energy from the Sun to other forms of energy is possible. Chiefly, it is transformed to thermal energy and electrical energy, and utilized in many applications. Thermal energy, also known as heat energy, from the Sun is employed as water heating as is used at home for domestic purposes, in buildings and in hot water swimming pools. Also it is used as heat spaces, typically, used in greenhouses, for domestic purposes, and in other buildings. Moreover, if converted to electrical energy, it has two major applications. Firstly as solar cell, also known as photovoltaic cell, in which electrical energy is formed directly from solar radiations. There are often installed in the localities where there electric power stations are far away. Apart from it, it is widely used in watches, calculator, and street lights.

Electrical power plants, energized from the Sun, work on the fluid medium which on conversion into steam runs an electric generator. In the United States, at the end of the year 2006, there were 15 such solar power stations were in operation. Out of which, 10 were installed in California alone and the remaining were in Arizona. There are other solar stations also, operational in many other parts of the United States, which produced less than 1 megawatt of electrical power.

Solar Energy – Infrared Radiations

Electromagnetic spectrum is lying between the visible and the microwave region is the infrared band spectrum. Like visible light, infrared also has a range of wavelengths. Closer to the visible spectrum band is the 'near infrared' while closer to the microwave spectrum band is the 'far infrared'. The shorter wavelengths are nearly cell-sized and microscopic, while the longer ones have size of pin head.

Longer wavelengths of infrared waves, far infrared, are more energetic. The warmth from the Sun can be experienced as heat energy from the Sun as in warm sidewalk which owes its warmth to infrared radiations. Fast food restaurants often employ infrared in specifically designed lamps and in cooking food. Remote controls that come with the television sets use shorter wavelengths of infrared radiations that are less energetic and not at all hotter.

The warmer the body, the more infrared waves it radiates. Therefore hotter bodies are the major source of the infrared radiations; rather colder bodies like ice cubes also radiate waves in the infrared region. A body unable to radiate in visible region radiate in the infrared region. For instance, heat felt from hot charcoal is the result of the infrared waves radiated from it. At ordinary temperature human body emit infrared waves of 10 microns more consistently. Infrared imaging using specially designed cameras, by giving different brightness, is used to distinguish differences in body temperature which are otherwise undetectable in visible light.

Humans are unable to sense infrared waves while snakes, like rattlesnakes, identify warm-blooded animals with their sensory pits used to image infrared radiations. Apart from animals and human bodies, various heavenly bodies radiate in infrared region like the Earth, the Sun, distant stars, etc. Infrared radiations reflected or radiated from the surface of the Earth are studied with the special sensors like those installed on GOES 6 and Landsat 7 satellites. Infrared coming from the large clouds of dust and gas, stars, and galaxies are explored using Infrared Astronomy Satellite and other satellites.

Solar Energy – Ultraviolet Waves

Radiations from the Sun are made up of a large spectrum, from radiations of shorter wavelength to longer wavelengths. The shorter wavelength of invisible sunlight is known as ultraviolet radiations. Invisible to the normal human eye, they are still visible to some insects like bumblebees. Scientists classify ultraviolet radiations into three regions: the near, the far, and the extreme ultraviolet regions. These are differentiated by their energy and the wavelength related to radiated energy.

The closest to the visible light is the near ultraviolet radiation, abbreviated as NUV. The most energetic of them is the close to the X-rays known as the extreme ultraviolet radiations, abbreviated as EUV. The least studied of them is the far ultraviolet, abbreviated as FUV, lies between near and extreme ultraviolet regions.

Sun radiates energy of various wavelength but ultraviolet radiations alone are accounted for the sunburns caused by the Sun. Most of the ultraviolet radiations are blocked by the blanket atmosphere around the Earth composed of ozone and other gases. Ultraviolet index is used to measure the radiations coming into the atmosphere and help people avoid its harmful effects. Protection from the ultraviolet exposure is encouraged. Astronomers use telescopes installed on satellites to calculate the extent of these radiations coming from the stars, galaxies, and particularly from the Sun. Near ultraviolet radiations are studied with Hubble Space Telescope form distant stars and galaxies. For over 17 years far and near UV radiations are being studied with the International Ultraviolet Explorer. Presently, extreme UV radiations are observed with the help of NASA's Extreme Ultraviolet Explorer.

Ultraviolet radiations help us explore the behavior and nature of far off stars and galaxies. Researchers are curious to explore invisible ultraviolet rays as the majority of heavenly bodies in the universe emit huge quantities of ultraviolet energy. Galaxies look different depending upon the intensities of the visible and ultraviolet wavelengths. The composition and evolution of galaxies is discovered using these comparisons in intensities.

Solar Energy – Visible Spectrum

Spectrum is the dispersal of white light (visible wavelengths), coming from the Sun after passing through the prism, into a band of seven colors since it is a continuous blend of seven colors. Typically, it also imparts the unwanted chromatic aberration in lenses. Electromagnetic spectrum is broadly termed for the full band of the solar radiation from the Sun. light from the Sun consists of tiny particles known as photons which travel with the speed of light at 300,000,000 meters per second.

Depending upon the energy they carry are reflected, passed or absorbed. If they are reflected back and come into our eye we see the illuminated body from where it is reflected. Transparent materials allow them to pass through like glass and water. Black bodies absorb them, so that are not seen once they have been absorbed. Reflection, passing through or absorption all depends on the energy of the radiation.

Light has its wave nature also. The measurements based on the wavelengths helps to explain the behavior of light after striking the leaf. Wavelengths of blue light travel more slowly than wavelengths of red light in the transparent media. Red light due to its largest wavelength (in the visible spectrum) is absorbed in the chlorophyll present in the leaf. The same is the case with the blue light due to its longest wavelength also. Green light lying in between the two colors is allowed to pass through or is reflected.

Visible light is a minor part of electromagnetic spectrum which is made up of electric field and magnetic field. The two fields are at right angle to each other. Explanation of some of the properties of visible electromagnetic spectrum is possible taking into account its wave nature while particle nature helps in the justification of some others properties. Hence light has both the particle and the wave nature, also known as wave – particle duality.

Solar Energy – Nature and Composition

Sun is the main source of energy on the Earth. Life sustains on the Earth because of electromagnetic radiations and without the Sun, the Earth would have 270 degree Celsius of equilibrium temperature. The Earth emits an equal amount of energy as it receives from the space, so there is a heat balance on the Earth. The Sun pours a huge quantity of electromagnetic energy on it and everything on the Sun is the source of these radiations. The Sun emits over a wide range of electromagnetic radiations. The incident solar energy, mainly, is in the visible part of the solar spectrum, while the key part of the radiation lies in the infrared region.

In eight minutes the radiation emitted from the Sun gets to the Earth. The ray which lightens up the surface of the Earth is the visible light, also known as white light, which is the continuous mixture of colors. This light when passed through the prism disperses into a band of seven colors. The energetic part of the spectrum is the ultraviolet radiation, which is undetectable having shorter wavelengths compared to white light. Those of ultraviolet radiations having extremely shorter wavelengths are filtered in the outer atmosphere by the ozone layer.

Thermal radiations, as they are referred to, are the invisible infrared radiations having longer wavelengths compared to those of white light. Mostly, the incoming infrared rays are filtered by the atmosphere of the Earth containing water vapors. The opacity of the atmosphere, chiefly, is responsible for maintain the warmth of the Earth, although the surface of the Earth is rather transparent to the longer wavelengths in the infrared region.

Besides optical radiations from the Sun, solar energy spectrum contains radio and X-rays also. Hotter bodies emit a larger wavelength of spectrum. Intense radio waves have been observed over the Sun's surface at 330 MHz having wavelength of about one meter. The studies of wavelength in the X-rays component of the electromagnetic spectrum are made by specially designed sensitive imaging techniques.

Solar Energy – Types of Concentrating Solar Power

Energy obtained from the sunlight is termed as concentrating solar power. Parabolic shaped troughs are used to collect energy from the Sun. Solar power station in Kramer Junction in California is one such example. Fossil fuel is also used in many others as a source of heat to heat water. This generates steam which is used to run large sized turbines and provides the spin to generator to generate electricity. Recently, more advanced electrical power generators make use of focusing solar radiation actually as their heat source.

Typically linear concentrator, dish or engine, and power tower system are three foremost varieties of concentrating solar power systems. Long rectangular mirrors which are curved in shape to focus the energy from the Sun to use it, is employed in linear concentrators. These mirrors are directed in the direction of the Sun which collects light from the Sun on the receivers (or tubes) that lie along the length of the mirrors. A fluid circulates through these tubes which got heat up. This heated fluid is then utilized to boil water usual turbine generator running on energy coming from the steam to generate electricity. Linear concentrators are further classified into parabolic trough systems and Fresnel reflector systems. Receiver tubes are oriented in line with the central line of parabolic mirrors in the former type, and one receiver tube is oriented over many mirrors so as it is easier for the mirror to follow the Sun.

Engine or dish system employs a huge satellite like mirrored dish which allows and focuses radiations from the Sun on a receiver, also called thermal receiver. Its absorbing surface accumulates the heat and takes it to the engine generator. Stirling engine is the commonest of its types. Pistons are installed inside which arte run by the energy from heated fluid thus making mechanical power. This mechanical power further runs a generator and produces electrical energy.

Power tower system employs heliostats which are flat mirrors to direct and focus light from the Sun to a tower top where it is received by a receiver. Heated fluid runs the turbine which in turn runs the generator to create electricity. Water or steam is also used in a few of them as a fluid medium to heat transfer. Researches on molten nitrate salt are also in progress owing to its greater heat transfer and energy storage potentials which allows its unhindered working at night time and overcast weather.

Solar Energy – Comparison of Efficiency

Space solar cells and terrestrial solar cells need a diferent method to measure their efficiency to avoid perplexity. In the absence of atmosphere in space, the solar spectrum is unfiltered while on the Earth, the atmosphere exists which filters the sunlight entering the Earth's atmosphere, thus changing it. To measure the filteration and its effects a system had been devised. The impact of filteration ranges from Air Mass 0 in the soace to about Air Mass 1.5 on the Earth. Efficiency of the devise can be found by takinkg spectrum differences together with quantum efficiency of the solar panel. For instance, a solar panel in space made from Silicon might be 14% efficient at Air Mass 0, whereas being 16% efficient on the Earth at Air Mass 1.5. Terrestrial solar cells are generally more efficient than space solar cells.
Efficiency of the solar panel ranges from 6% (for amorphous Silicon based solar panels) to 40.7% (with multiple junction cells in a research lab) and 42.8% (of assembled hybrid package of multiple dies). Conversion of energy for multicrystalline Silicon solar panel availabe commercially has approximately 14-19% efficiency. The more the solar pcell is effficient, the more it will be costly. For instance, a indium selenide or gallium arsenide multi-junction solar panels are produced in lesser quantity, are 30% efficient and cost 100 times less as compared to 8% efficient amorphous Silicon solar panel produced on large scale, and delivers around four time the electrical power.
There is, however, a method to enhance the solar power. By increasing the solar brilliance, usually solar power generation is increased, having enhanced efficiency up by 15%. Concentrator systems, as they are known, have only got to be cost effective, as a result of the improment in the highly efficient gallium arsenide solar panels. The rise in brilliance is ideally done by the use of concentrating optical instruments. An ideal concentrator system may employ an intensity of light 6-400 times the Sun, resulting in efficiency improvement of a single gallium arsenide cell from 31% to 35% at Air Mass 1.5.

Solar Energy – How is Night Time Usage Possible?

Heat energy accounts for the extent of internal thermal energy possessed by the body and depends upon the temperature and the mass of the body. The basics of solar thermal energy lies in five principles namely heat gain, heat transfer, heat storage, heat transport, heat insulation. Storage of solar energy makes it possible to benefit from it in the absence of sunlight also.

Heat gain is the measure of the heat in the system collected from the sun. Greenhouse is used to collect the heat energy from the solar radiation which employs greenhouse effect. The greenhouse effect is the capability of the reflective surface of allowing short wave radiations while reflecting long wave radiations. When sunlight strikes the absorbing surface it is, there and then, entrapped in the collector. Absorber tubes, filled with fluid like water, are used to entrap heat energy and transmit it to the heat storage vault.

Conduction or convection transfers heat energy. In heated water, water molecules get kinetic energy by conduction process in the medium. Owing to possessing thermal energy hot molecules occupy more space than cold slow moving molecules which are above them. Because of convection process the hot water molecules rise up and cold water molecules sink down thus being accounting for the throughout spreading of energy. From the absorber plates of the collector, energy is conveyed by conduction. Delivery pipes circulate the fluid from the collector and take it to heat transfer vault where it is distributed all over the medium by convection process.

Solar thermal power units store the heat energy thus producing electrical energy during night time and when the weather is overcast. During sunlight the heat is transmitted to the thermal storage medium which is benefited from during hours lacking natural sunlight. Temperature differences as well as conduction and convection directly affect the rate of heat transfer. The larger the temperature difference, the faster will be the heat transfer.

The process of heat energy transfer, from solar collector unit to the heat storage vault, is known as heat transport. In both the heat transport tubing and the storage vault, heat insulation is imperative which minimizes heat loss, which is in line connected to energy loss, or downfall in the system efficacy.

Solar Energy – Power Generation

Device which can generate electric power from sun radiation is known as solar cell or photovoltaic cell. Solar is particularly used for the power generation when the enrgy conversion source is sun light where photovoltaic use any light source. The production of energy like this called solar energy, also known as solar power.

Eergy conversion efficiency of the solar panel is the percentage of the power changed from absorbed sunlight into electrical energy, when solar panel is connected to an electrical circuit. Depending upon the time when it become important these can broadly be classified in three generations. Big sized, good quality and uni junction panels are included in first generation solar panels. These were expensive owing to large power and initial labor costs which was the major reason for cosltiness. Taking into account their efficiency these can be upto 33% efficient.

Technology advancements not only improved its quality in the second generation solar panels but also made it coast effective. Use of different production techniques like that of vapous deposition, electoplating and others helped to achieve it. Employing materials like cadmium telluride, copper indium gallium selenide, amorphous silicon and micromorphous silicon not only reduced material mass but also production expenses while not compromising on the quality and efficiency.

Third generation methodologies are focused at achieving the higher level of efficacy and elimination of the drarbacks in the second generation cells while not compromising on the manufacturing price. Presently, the goal is to get to the efficiency level of 30-60% whereas to contain productivity pricehike using the privailing methods. But enhancing efficacy also effects its inputs making the target much difficult to achieve. Still there are some mesns to get it with the usage of multi junction solar panels, concentrating the coming radiations and the usage of ultraviolet radiations, or the application of infrared radiations which can improve voltage generation particularly for night time working. Resarches are going on to make solar energy yet a better source of power.

Solar Energy – Solar Forcing

Measure of the variations in the quantity of sunlight emitted by the Sun refers to solar variation. Solar variations are time dependent. There are recurring as well as non-recurring solar variations. Solar activity, during recent decades, is calculated by means of satellites. Weather and upper space scientists are concerned with identifying the aftermaths of solar activity on Earth. The impacts of solar activity resulting from solar activity are called 'solar forcing'.

Solar variations remained unidentifiable at or below the level to be noticeable until the satellite age. These are calculated at an average of 1,366 watts per square meter at the upper Earth atmosphere. There are no direct findings of the long-term changes. These variations range from ~ 0.1% over last 2000 years to ~ 0.2% just since 17th century. These together with volcanic effects have most probably added to the environmental changes. Solar magnetic activity impacts on environment, from cosmic rays or ultraviolet radiations, can not be ruled out let alone solar brilliance variations.

The first ever recorded solar variations are the changes noticed in the Sun as sunspots. Comparatively dark regions on the radiating surface of the Sun, where strong magnetic activity slows down convection and cools the surface, are sunspots. Cyclic changes in behavior of the Sun are solar cycles of which 11 and 22 years are mostly identifiable. For longer solar cycles the impact is higher, resulting in higher frequencies caused by the thermal inertia of the ocean. Solar irradiance varies gradually for longer time period which during recent activity ha been measured to about 0.1%. Variations in the ultraviolet radiations' energy results in loss of ozone and has climatic effects. Intense magnetic fields and solar wind decrease the radiations coming to the Earth. Cloud formation is assumed to have been changed due to cosmic radiations. Change in the electromagnetic fields at the surface of the planet is the result of the interaction of particles in the Sun, and the Sun's and the Earth's magnetic field. Electrical devices are also affected by powerful solar events.

Solar Energy – Solar Thermal Energy

Solar thermal energy is a technique of using light energy from the Sun to convert it to heat (thermal) energy. USA Energy Information Administration describes solar thermal units as low, medium, or high temperature solar units. Flat plates commonly employed in swimming pools to heat them up are low temperature solar units. For home and industrial scale heating of water medium temperature solar units, normally flat paneled solar units are used. Focusing light from the Sun employing mirrors or lenses is the working principle of high temperature solar units which are used for the production of electrical energy while photovoltaic cells, directly, convert light energy into electrical energy.

United States, in 2006, manufactured 21000,000 sq ft (2,000,000 square meter) solar thermal units from which 16,000,000 sq ft (1,500,000 square meter) were of the low temperature solar units. Generally, to heat up water in the swimming pools, low temperature solar units are installed, where space heating is another of their application. In these solar units air or water is the medium for transfering heat to its destination. In the United States, medium temperature solar units are employed for 50% of the heated water consumed for home and industrial usage. Such solar units, in the United States, prices to $5000–$6000 with a payback time an ideal home is nine years and half of these systems qualifies for a tax credit. Moreover, these have negligible maintenance price also minimizes CO2 emissions by 1 ton/year (as substitute to natural gas for water heating) or 3 ton/year (as substitute to electrical water heating.

High temperature solar units, of non-concentrated type, are installed like for space heating where temperatures below about 95°C are required, whereas the temperature of 150-220°C can be attained using non-circulating fluid-filled pipes. This temperature is minimal for efficient conversion to electrical energy. The temperature of the heat source varies inversely with the efficiency of heat engines. Using mirrors or lenses sunlight is focused to obtain higher temperatures — a technonolg called Concentrated Solar Power (CSP). It efficieltly minimizes the plant size and area required for per unit power generation, and hence cutting down the environmental effects of a power plant.

Solar Energy – Solar Energy in Home

Solar energy is the light and heat emitted from the Sun that man use from times employing innovative means. On Earth, most of the accessible renewable sources, are rays from the sun alongwith secondhand replacements like wind and wave energy, hydro-electricity and biomass. Using heat engines and photovoltaic panels, it can provide us electricity. Heating and cooling, water sterlization, daylighening, food processing, and high temperature treatment in industry are all solar systems.

Solar energy, chiefly, is the use of sunlight for everyday usage. All recycleable sources of energy, except geothermal and tidal, have their orignality from the sun. These, by and large, are considered as being active or passive accounting the way of conversion and distribution of rays from the Sun. Photovoltaic cell which convert light from the sun into various products are considered as active solar method. However, positioning a built structure to the Sun so that natural cross ventilation can take place is known to be a passive means. Active solar methods boosts the energy supply, while passive solar methods lessen the requirement for substitute resources, so are commonly understood as supply-side and demand-side methods respectively.

Interior of a building can be illuminated using solar daylighting system which uses sunlight. Solar thermal methodologies can be beneficial in water and space heating, space cooling and heat production. Hot water systems can also be made to take in sunlight to heat it up. Solar cookers operate on solar radiations to cook, dehydrate and pasteurize food items. Solar panels can be employed to produce electricity.

In the United States, heating, ventilation and air conditioning systems counts to 30% of the power in use in business and trade localities and almost 50% of the power in use in personal buildings. These methods can be used to counterbalance a part of the energy used. Only a small portion of the available solar energy is in use, which if used proportion to its availability, can take over the never ending energy demands.