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What is solar energy?

Solar energy is the energy that comes from the sun. The solar energy that comes from the sun is enough to give us all the energy that we need. It is also important to note that all forms of energy. From fossil fuels to wind energy can be traced back to energy that is originally supplied by the sun. Learn more on solar energy

HOW DOES SOLAR ENERGY REACH THE EARTH.

At this point, I should say that the intensity of solar radiation. Varies with the square of the distance traveled. Between earth and the sun.In order for you to understand how solar energy travel to reach the earth. There are a number of factors to be considered.

  1. Atmospheric clarity
  2. Distance of travel through the atmosphere
  3. The angle of incidence.

ATMOSPHERIC CLARITY.

This is the condition of the atmosphere at any time of the day. When I talk about atmospheric clarity, I refer to the state of the atmosphere. Below is a list of the conditions:

  • Clear
  • Cloudy
  • Raining
  • Dusty
  • Windy

For this reason, it is important to note that the best days for solar gain are clear and dry.

Cloud cover, rain, humidity air pollution and dust in the atmosphere, all reflect, absorb, and scatter solar radiation. There fore, energy reflected back into space, is lost to us.

Absorbed radiation heats the atmosphere. And is responsible in part for the wind that turns the wind turbines. This bad thing is the absorbed energy is not available for direct collection.

Direct radiation, and some that are scattered by the atmosphere, makes up the total radiation available to solar collectors

DISTANCE OF TRAVEL

The quality of solar radiation reaching the piles of the earth’s surface.It is affected by the distance it travels through the atmosphere. The energy that is not scattered is absorbed by:

  • Moisture
  • Gases
  • Dust.

The greater the distance traveled, the greater the sun’s energy is lost in the atmosphere. When you study the distanced traveled by solar energy through the atmosphere, you will realise that it is affected by:

  • Time of the day
  • Latitude
  • Season
  • Altitude.

At sunrise and sunset, the sun’s energy most travel through far more atmosphere than in the middle of the day.

Latitude also affects the distance the sun’s energy must travel through the atmosphere. The closer you are to the equator, The less atmosphere between you and the sun.

Regardless of where you are, you receive more solar energy in summer than at any time of the year.

Altitude above sea level also affects how much solar energy you receive. The person on a higher altitude will receive more solar energy than a person at a lower altitude. This because when you are on high altitude, the distance of travel through the atmosphere to earth’s surface is reduced.

SOLAR ANGLE OF INCIDENCE AND INCIDENT OF RADIATION

What is the solar angle of incidence? This is the angle at which the sun’s ray strikes the earth’s surface. It is this angle that determines the intensity of the solar energy reaching the earth’s surface. I know you may be asking as to what is the solar intensity. This is the amount of solar energy or sunlight striking the earth’s surface.

How does the angle of incidence affect the intensity of solar energy? Let us take an example of the sun at midday. At midday, the sun’s ray strikes the earth’s surface at a right angle. This shows that the intensity of solar energy is more at mid-day than at either sunrise or sunset.

The other thing to note is that when the sun strikes the earth’s surface at a right angle. The sun’s rays are closely packed, and covering a small area, but with high intensity. When the sun’s ray strikes the earth’s surface. Let’s say at 45 degrees, the sun’s ray covers a wide surface area but with reduced solar energy intensity. The intensity of solar energy reduces with the reduction of the angle of incidence.

How is solar Energy used in real life?

I would like to say that with the increase in the cost of convention form of energy. More people are looking for alternative forms of energy. Not only are we faced with an increase in the cost of energy. But the pollution of the environment as well. Therefore, more and more people are looking for alternative forms of energy. That contributes to protecting the environment. Thus maintaining a clean and green environment.

I will highlight ways in which solar energy is used, by limiting the discussion to two methods of capturing solar energy. The methods used to harvest solar power are:

  1. Solar thermal collectors and
  2. Solar electric collectors

Below is the various specific way solar energy is used.

  1. Solar hot domestic water
  2. Solar pool heating
  3. Solar electricity
  4. Other uses of solar energy.

SOLAR THERMAL COLLECTORS

Evacuated tube collectors

For you to understand and appreciate solar thermal collectors. It is desirable to know that there are two types of solar thermal systems. What are these two ways of capturing solar thermal energy? The first one is passive and the second one is active.

A passive solar system captures the sun’s energy as it enters a building without relying on a motor-driven circulator or fan. Once the captured energy is in the house. It can be stored in the mass of the building and distributed by natural means.

An active solar thermal system . Collectors capture the sun’s energy as heat. Then the collector transfers the heat through a liquid. The heated fluid is moved through the collector by a motor-driven circulator or fan. The heated water is then transferred or taken where it can be used immediately or stored to be used later.

SOLAR HOT DOMESTIC WATER

In all solar hot domestic water, the system starts with the collectors. It is worth to know from the word go. To say that there are basically two types of solar thermal collectors.

  1. Standard flat-plate collectors and
  2. Evacuated tube collectors.

DIRECT AND INDIRECT SYSTEMS

The direct system also is known as an open-loop system circulates potable water directly through the collector. The heated water is then stored in a water tank.

The indirect system also known as a closed-loop system, circulates a non-portable liquid. Often a non-toxic antifreeze, between the collector and the heat exchanger. which eventually heats the water.

ACTIVE AND PASSIVE SYSTEMS.

The thermal heat collector systems can further be classified as either being active or passive.

An active system, a circulator is used to move either water or an antifreeze liquid through the collector. While a passive system relies on natural means to move water or an antifreeze liquid through the collector.

I know you might be asking, what system is the best. Honestly speaking, the climate is a determining factor in the choice of the system to use. In areas that experience freezing in winter and cold seasons, a less efficient and more complex indirect system must be used. In places where freezing is not an issue, a simple direct system should be used.

SOLAR DOMESTIC HOT WATER SYSTEM COMPONENTS.

To have a complete solar domestic hot water system, the below-listed system components should be present. Depending on the system used, all or some of the components must be present in the system.

  1. Solar thermal collectors
  2. Supplemental water heaters
  3. Hot water storage tank
  4. Piping
  5. Collector coolants
  6. Expansion tanks
  7. Heat exchangers
  8. Circulator
  9. Backflow preventer
  10. Thermal static mixing valve
  11. Supplemental heat bypass
  12. Isolation valve
  13. An AC collection loop control
  14. A DC collection loop control.

SOLAR THERMAL COLLECTOR.

This is the most important or the heart of any solar system. Most solar hot water collectors are mounted on the roof. these collectors can either be standard flat-plate or evacuated tube collectors.

SOLAR HOT WATER STORAGE TANK

There are basically two ways to store water in a solar hot water system. The more common approach is to use a pressurised tank containing portable water that has been heated by the solar array.

The second method is to use unpressurised tank containing potable water heated by the solar array passed through a heat exchanger. the heat exchanger can either be inside or outside the tank.

SUPPLEMENTAL WATER HEATER

All types of solar hot water heaters that operate the whole year, should have a supplemental source of supplemental or back up water heaters that are used to boost the temperature of the solar-heated water.

PIPING

All solar hot water systems rely on piping running from the collector to the tank. Over the years, copper smooth pipes have proved to be the most reliable.

COLLECTOR COOLANT

The type of coolant used depends on the system in use. In direct systems, portable water is the coolant used to transport heated water from the collector to the storage tank.

While in an indirect system, a non-portable liquid is used to transport heat from the collector to the storage tank.

EXPANSSION TANK

The coolant expansion tank is required in an indirect filled closed system to cope with the expansion and contraction of the collector fluid to maintain near-constant pressure in the system.

HEAT EXCHANGER

This is an important part of an indirect system. It transfers heat from the collector coolant to the portable water.

CIRCULATOR.

Circulators also called pumps, are used in active systems. Both direct and indirect.To circulate water between the collector and the storage tank.

BACKFLOW PREVENTER

A backflow preventer is used in indirect systems. The work of this component is to prevent non-portable liquid from being drawn back when there is a loss in pressure or a leak in a heat exchanger.

ISOLATION VALVE

Two-way valve for isolating key components make repairs or replacements possible without draining the entire system.

AN AC COLLECTION LOOP CONTROL

In active systems using AC powered circulator, it is important to provide a means of controlling the AC circulator.

A DC COLLECTION LOOP CONTROL.

Just like in an AC power circulator, there must be a way of controlling a DC there must be a way of controlling a DC circulator.

SOLAR POOL HEATING.

In this system, solar is used to heat the pool. Basically a pool can be heated by using the two systems of heating.

  1. Solar thermal heating and
  2. Solar electric heating system.

Seeing that heating a pool is an important task, but few people need their pools to be heated, therefore,it is not my intention to go into the details on how solar pool heating is done.

CONVERT SOLAR TO ELECTRICITY

Just like in hot solar domestic water heaters, for solar energy to convert to electricity, it needs solar electric collectors. Solar electric collectors , convert solar radiation directly into electricity. Solar electric collectors can either be modular or laminate.

When solar energy is converted to electricity,it is in direct current form. Therefor an inverter is used to convert DC power to AC.

TYPES OF SOLAR ELECTRIC COLLECTORS.

The collectors are made from either monocrystalline or polycrystalline cells. Mono and polycrystalline modules are the majority of solar modules on the market.

Polycrystalline electric collectors are more popular and less expensive than a monocrystalline module. When a semiconducting material is protected by glass and it is not flexible it is called a module. And when it is protected by a flexible cover it is called a laminate.

At this point, it is good to mention that a single solar cell combines to form a module and modules form arrays.

SOLAR ELECTRIC SYSTEM FOR THE HOME.

There are basically three types of domestic solar electric systems.

  1. Off-grid
  2. Grid-tied without batteries
  3. Grid-tied with back up batteries.

OFF-GRID ELECTRIC SOLAR SYSTEM

An off-grid solar electric system is one that solely depends on electricity supplied by the solar array.

HOW DOES AN OFF-GRID SOLAR SYSTEM WORK?

An off-grid solar electric system uses solar electric modules to charge the battery banks through a charge controller. The DC current from the batteries can be converted to AC, using an inverter. Or the DC current can be used directly. This is possible when all loads connected in the house use DC.

SYSTEM COMPONENT OF AN OFF-GRID.

  1. SOLAR ELECTRIC ARRAY
  2. CHARGE CONTROLLER
  3. BATTERY BANK
  4. DC DISCONNECT
  5. MODIFIED SINE WAVE INVERTER
  6. AC DISCONNECTOR
  7. MAIN ELECTRIC PANEL

GRID-TIED SYSTEM WITHOUT BACK UP.

grid-tied without battery
Grid-tie

This is a domestic solar electric system that is connected to the main utility company electric grid.

Grid-tied systems supply AC electricity into the main circuit breaker box(Distribution board). That is also serviced by the utility power company. This makes it easy for the house to get power from either its solar electric modules. Or when this is not possible, from the utility grid.

It is important to note that in this system, the inverter that converts DC electricity from the solar arrays to AC electricity constantly monitors the quality of power from the grid.

Should the power quality from the gird go down or below a certain standard. The inverter shuts down automatically. Until the power utility quality is stable, for about 5 minutes. This feature helps protect utility workers who may be working in nearby areas.

SYSTEM COMPONENTS OF A GRID-TIED SYSTEM.

  1. SOLAR ELECTRIC ARRAY
  2. DC DIS CONNECTOR
  3. INVERTER
  4. OUTDOOR AC DISCONNECTOR
  5. MAIN ELECTRIC PANEL
  6. UTILITY METER
  7. AC UTILITY GRID

GRID-TIED WITH BATTERY BACK UP.

Grid -tied with battery back up
Grid-tie with battery back up

In the grid-tied solar system with battery back up. The battery backs up supply power to critical loads when the utility power fails. This system is ideal in areas where load shading and utility power failures are common.

A grid-tied system with battery backs up supplies AC electricity. To the main electric panel that is also serviced by the power utility company. The house can get its power supply from its solar module or the utility company.

When utility power fails. The solar electric system switches from the main electric panel to supply AC power to separate the critical load panel.

SYSTEM COMPONENTS OF A GRID-TIED WITH BACK UP.

  1. SOLAR ELECTRIC ARRAY
  2. CHARGE CONTROLLER
  3. DC DISCONNECT
  4. TRUE SINE WAVE INVERTER
  5. OUTDOOR AC DISCONECTOR
  6. CRITICAL LOAD ELECTRIC PANEL
  7. MAIN ELECTRIC PANEL
  8. AC DISCONNECT
  9. UTILITY METER
  10. UTILITY GRID

OTHER USES OF SOLAR ENERGY.

Solar energy has many applications, I will list a few other ways solar energy can be utilized.

  1. Solar attic fans
  2. Outdoor solar lighting
  3. Solar-powered
  4. solar dehumidification
  5. Drying clothes outdoors
  6. Daylighting
  7. Cooking with solar energy
  8. Drying food
  9. Solar desalination
What is solar energy in simple words?

Solar energy is the energy that comes from the sun. The solar energy that comes from the sun is enough to give us all the energy that we need. To power your machines, house for both lighting and entertainment. Solar can be used as a buck or stand-alone off-grid system.

What are the 3 benefits of solar energy?

1. Solar systems have low maintenance costs.
2. Solar energy is renewable meaning that it can not be deleted.
3. When you incorporate solar energy into your existing power supply from your national grid, you can reduce the amount of money that you pay towards electricity bills.

How does solar energy work?

Solar energy works with the help of solar collectors. Solar collectors can either be an electric solar collector or thermal solar collectors. The solar collector collects solar energy from the sun then transforms it into electricity. The electricity that is produced by an electric solar collector is DC in nature. With the help of an inverter, the DC power is changed or converted to AC power.

Should you have any questions feel free to comment below.

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