Renewable Energy - Volume 1: Solar, Wind, and Hydropower: Definitions, Developments, Applications, Case Studies, and Modelling and Simulation

Renewable Energy - Volume 1: Solar, Wind, and Hydropower: Definitions, Developments, Applications, Case Studies, and Modelling and Simulation is a comprehensive resource for those wanting an authoritative volume on the significant aspects of these rapidly growing renewable technologies. Providing a structured approach to the emerging technologies and advances in the implementation of solar, wind and hydro energy, the book offers the most requested and desirable practical elements for the renewable industry. Sections cover definitions, applications, modeling and analysis through case study and example.

This coordinated approach allows for standalone, accessible, and functioning chapters dedicated to a particular energy source, giving researchers and engineers an important and unique consolidated source of information on all aspects of these state-of-the-art fields.

• Includes in-depth and up-to-date explanations for the latest developments in Solar, Wind and Hydropower
• Presents a uniquely, thematically arranged book with structured content that is easily accessible and usable
• Provides extensively illustrated and supported content, including multimedia components like short videos and slideshows for greater examples and case studies

• Language: English
• Publisher: Academic Press
• Release date: Apr 29, 2023
• ISBN: 9780323995696

Book preview

Section 1

Solar thermal energy

Outline

Chapter 1.1 Sun composition, solar angles, and estimation of solar radiation

Chapter 1.2 Development of solar thermal energy systems

Chapter 1.3 Solar thermal energy applications

Chapter 1.4 Case studies and analysis of solar thermal energy systems

Chapter 1.5 Thermal analysis of solar collectors

Chapter 1.6 Energy and exergy analyses of a photovoltaic/thermal (PV/T) air collector

Chapter 1.1

Sun composition, solar angles, and estimation of solar radiation

Bashria A.A. Yousef¹, Ali Radwan¹,², Abdul Ghani Olabi¹,³ and Mohammad Ali Abdelkareem¹,⁴,    ¹Sustainable and Renewable Energy Engineering Department, College of Engineering, University of Sharjah, Sharjah, United Arab Emirates,    ²Mechanical Power Engineering Department, Mansoura University, El-Mansoura, Egypt,    ³School of Engineering and Applied Science, Mechanical Engineering and Design, Aston University, School of Engineering and Applied Science, Aston Triangle, Birmingham, United Kingdom,    ⁴Faculty of Engineering, Minia University, Elminia, Egypt

Abstract

Sun radiation is the source of most types of renewable energy and can be consumed through indirect or direct uses. The indirect solar forms are:

• Hydro power where solar energy is consumed by the hydrological cycle of evaporation and precipitation, feeding rivers, which can drive turbines.

• Wind and wave energy which are formed due to temperature differences on the earth's surface.

• Bioenergy that is used as biofuels is formed from the carbohydrates resulting from the photosynthesis process.

The direct solar conversion of solar irradiation can be in the form of thermal energy using solar collector or electricity generation through photovoltaic devices. The solar thermal system efficiencies range between 40% and 60%, while PV has efficiencies between 10% and 20%. Currently, solar thermal systems are extensively installed worldwide for both domestic and commercial usage. Solar power is very cheap compared to other sources of energy generation. They are also abundant and suitable for several applications.

This chapter introduces brief points about the sun’s structure and characteristics and nature of sunlight. It concerns with the main definitions of the solar radiation, its intensity, and spectral distribution as well as the solar angles. The chapter presents the characteristics of solar radiation outside and inside the earth’s atmosphere. It discusses the extraterrestrial radiation on normal and horizontal surfaces, and also, it presents the methods and steps to evaluate the terrestrial radiation on tilted surface.

Keywords

Solar angles; extraterrestrial radiation; terrestrial radiation; radiation on a tilted surface

1.1.1 Sun composition and nature of sunlight

The sun consists of an intensive hot gaseous matter, and it has a sphere shape of diameter and is about from the earth. It rotates around its axis once every 4 weeks that takes about 27–30 days. The sun has an effective blackbody temperature of 5777 K [1]; however, as shown in Fig. 1.1.1, the sun consists of several layers at different temperatures and densities. The temperature at the center of the sun (known as the core region) is in the range of , and its density is 100 times the density of the water.

Figure 1.1.1 Different layers of sun.

At the core, 90% of the sun energy is generated. At a distance of 0.7R from the center (where R is the radius of the sun), the temperature and density dropped to about ; at this region, the energy transfer occurs only by radiation in form of gamma and X-ray radiation. From 0.7R to R, the temperature and density experience more drop, the convection process starts to take place and becomes significant, and this region is known as the convective region. The outer layer of the convective zone is known as photosphere layer. The edge of the photosphere layer consists of gases that has an ability to absorb and emit continuous spectrum of radiation; due to that, the photosphere layer is considered as the source of most solar radiation. Above the photosphere is a layer referred to as the chromosphere, and further out is the corona layer.

Sunlight known as solar radiation is an electromagnetic radiation in visible and near-to-visible regions of the electromagnetic spectrum. Electromagnetic radiation characterized by energy packets is called photons, and the amount of energy contained in a photon is inversely proportional to the wavelength. This is represented mathematically by Planck–Einstein equation:

(1.1.1)

where is the amount of energy, are Planck’s constant ( ) and the speed of light in air ( ), respectively, and is the wavelength .

1.1.2 Solar radiation nomenclature

Solar irradiance: It is defined as the rate at which solar energy reaches a unit area of a surface, and it is described in watts per square meter .

Insolation: Incident solar radiation known also as insolation or irradiation describes the variation of solar irradiance over time, and it is expressed in terms of irradiance per time unit or ( )]. The insolation known also as insolation or irradiation is interesting for the designer of solar energy collection systems as it is needed to know how much solar energy has fallen on a collector over a period such as a day, week, or year.

According to [2], the four characteristics of insolation are of interest: (1) the spectral distribution of the light, (2) the radiant power density, (3) the incident angle on collector surface, and (4) radiant energy from the sun throughout a year or a day for a particular surface.

Emissive power: The rate at which radiation is emitted in all directions from a surface per unit area (leaves the surface only by emission) is described by .

Radiosity: It represents the rate at which radiation leaves a unit area of the surface by both reflection and emission, and it is expressed by .

Air mass: Due to the locations and time variations, the solar radiation passes through various distances at earth’s atmosphere, and the measurement of this variation represents the air mass which is defined as the ratio of the mass of the atmosphere through which direct radiation passes to the mass it would pass through if the sun was directly overhead (at the zenith) and is represented mathematically

(1.1.2)

where m is the air mass, and are the zenith and altitude angles, respectively.

When the sun is directly overhead, the air mass is equal to unity. The amount of air mass between any given point and sun depends on the sun’s elevation, atmospheric pressure, and the height of the point above the sea level. At high zenith angles that approaches degrees, which is near sunrise or sunset, the effect of the earth’s curvature becomes highly significant, and the air mass can be evaluated using the given expression [3] cited by [4]

(1.1.3)

where is the site altitude (m).

Beam radiation: It is the solar radiation received directly from the sun without having been scattered by the atmosphere, and it is known also as direct radiation.

Diffuse radiation: It is the solar radiation received from the sun after having been scattered by the atmosphere, and its direction has been changed.

Total radiation: Known also as global radiation, it is the sum of both beam and diffuse radiation, solar radiation received from the sun on a surface.

1.1.3 Solar time

There is a difference between the clock time (local time) and the solar time, and the relationship between them depends on the day within the whole year and the location within the time zone. The calculations of solar energy are based on solar time which depends on the apparent angular motion of the sun in the sky. To convert from clock time to solar time, two corrections must be applied. First one known is the equation of time, and it arises because the length of the day varies throughout the year. The second correction is longitude correction because the sun takes 4 minutes to transverse one degree of longitude. Therefore, a longitude correction term of 4 × (standard longitude – local longitude) should be either added or subtracted to the standard clock time; if the location is east of the standard meridian, the correction is added to the clock time. If the location is west, it is subtracted [5].

The solar time can be expressed as:

(1.1.4)

where refer to solar and local time, respectively, and represents the equation of time (minutes), and Day saving either , depending on whether daylight saving time is applied.

(1.1.5)

(1.1.6)

1.1.4 Solar angles

The position of the sun relative to a plane relative to earth at any time is described in terms of several angles. Some of the solar angles are shown in Fig. 1.1.2.

Figure 1.1.2 Solar zenith, solar altitude, solar azimuth angle, and surface slop and azimuth angles.

Declination : It is the angle of an object in the sky with reference to the perpendicular to the celestial equator. The angle of declination changes throughout the year due to the rotation of earth around the sun which results in different seasons. The axial tilt is 23.45 degrees, and the declination angle varies plus or minus this value [2]. At spring and fall equinox 21st March and 23rd September, respectively, the declination angle is zero degree, at winter solstice 21st December, it is −23.45 degrees, and at summer solstice 21st June, it is maximum and equal to 23.45 degrees (Fig. 1.1.3). It can be evaluated by the formula

Figure 1.1.3 Variation of the declination angle of the sun due to tilt of the earth on its axis of rotation.

Hour angle : It refers to the angle of the sun at any time of the day. The angle of the sun at solar noon is equal to zero degree, and the earth takes to rotate 1 degree and 1 hour to rotate 15 degrees; therefore, the hour angle can be estimated by one of the below equations.

(1.1.7)

(1.1.8)

Solar altitude angle : It is known also as elevation angle and defined as the angular height of the sun in the sky measured from the horizontal plane. The altitude angle varies from zero degree at sunrise or sunset to 90 degrees when the sun is at the highest point in the sky. It depends on the local latitude, the time of the day, and the day in the year. Altitude angle is related to the solar zenith angle which is the angle between the vertical and the line to the sun which is expressed by the following equations:

(1.1.9)

(1.1.10)

where L refers to the local latitude, which presents the angular location north or south of the equator, and the value of north is positive and negative for south.

At sunrise and sunset, the solar altitude is equal to zero; in this case, the hour angle in Eq. (1.1.9) represents the sunset hour angle, and the equation can be rewritten as:

(1.1.11)

where refers to sunset hour angle

Rearranging the former equation, the sunset hour angle is expressed as:

(1.1.12)

Since each 15 degrees of longitudes is equivalent to 1 hour, the sunset hour angle can be expressed in hours by dividing Eq. (1.1.12) by 15 degrees. Thus, sunset time in hours is

(1.1.13)

where is the time in hours at sunset.

The sunrise hour angle is the negative of the sunset hour angle, and it is expressed as

(1.1.14)

where is the time in hours at sunrise.

The solar noon is at the middle of the sunrise and sunset hours; therefore, the day’s length is twice the sunset hour.

(1.1.15)

Solar azimuth angle : It is the angular displacement of the sun’s rays on the horizontal plane from the true south (for northern hemisphere) or true north (for southern hemisphere), designated as negative for east-of-south and positive for west-of-south displacements, respectively, and expressed mathematically as:

(1.1.16)

At solar noon, solar azimuth is equal to , and the altitude at noon becomes:

(1.1.17)

where is the latitude (defined as angular location north or south to equator, north of equator designed as positive and negative for south).

Angle of incident : It is the angle between the sun’s rays on a surface and the normal to that surface, and it is the function of several solar angles

(1.1.18)

where and are tilt (slope) and azimuth angles of the surface, respectively. is tilt angle from the horizontal for the surface, and is the angle between the normal to the surface from true south.

To capture more of solar radiation, single-axis or two-axis (full) tracking mechanism system is added to the solar collector.

The two-axis tracking system keeps the collector oriented to face the sun at all times. Accordingly, both tilted and azimuth angles of the surface are equated to solar zenith and solar azimuth angles, respectively. Therefore, the angle of incident for full tracking system is equal to zero:

(1.1.19)

In the case of a single-axis mode, the collector can track the sun in various ways; however, the most common are horizontal east–west, horizontal north–south, vertical, and parallel to the earth’s axis [4]. The angle of incident and slope of the collector for each case are expressed as:

(1.1.20)

(1.1.21)

(1.1.22)

(1.1.23)

(1.1.24)

(1.1.25)

(1.1.26)

(1.1.27)

(1.1.28)

(1.1.30)

(1.1.31)

(1.1.32)

(1.1.33)

(1.1.34)

1.1.5 Sun path diagram

The position of the sun can be determined using simple diagrams known as sun path diagrams. The diagrams are plotted on a horizontal plane for each 1 degree of latitude for northern and southern hemispheres, showing complete variation of hour angles and declinations for whole year. Solar altitude can be read from vertical axis and solar azimuth from horizontal one. Fig. 1.1.4 shows sun path diagram for 35 degrees latitude.

Figure 1.1.4 Sun path diagram [6]. With permission No. 5450200972443.

1.1.6 Extraterrestrial solar radiation

The amount of solar radiation per unit area that is incident normally on a plane on the outer atmosphere when the mean distance between sun and earth is equal to is called the solar constant. The value of is adopted by World Radiation Center (WRC) for solar constant, with an uncertainty of the order of 1%.

The solar radiation at the outer edge of the earth atmosphere is known as extraterrestrial solar radiation, and it varies according to the distance between sun and earth at the time of the year. On the 3rd of January, it is about 1400 W/m² as the sun is closest to the earth, while it is about 1330 W/m² on the 4th of July when the sun is farthest from the earth as shown in Fig. 1.1.5. The normal extraterrestrial solar radiation incident on a plane is function on the number of the day in the whole year; it is shown in Fig. 1.1.6 and can be estimated using the formula given by [7] and [5]

(1.1.35)

where is extraterrestrial solar radiation incident on a plane normal to solar rays, ( ) is the solar constant ( ), and is the number of the day in the year.

Figure 1.1.5 Earth–sun distance variation.

Figure 1.1.6 Extraterrestrial radiation perpendicular to plane.

If the plane is placed parallel to ground (horizontal) at the limits of earth atmosphere as shown in Fig. 1.1.7, the rate of the extraterrestrial incident solar radiation will be function on both the number of the day in the year and the angle measured from the vertical, which is the solar zenith angle (ϕ). Thus, the latitude, declination, and solar hour angles will influence the extraterrestrial radiation on the horizontal surface . The expression to evaluate at any time during the day between sunrise and sunset hours is:

(1.1.36)

where is extraterrestrial solar radiation incident on horizontal surface ( ).

Figure 1.1.7 Extraterrestrial radiation parallel to plane.

To estimate the total for a day, Eq. (1.1.36) is integrated over a period from sunrise to sunset. The integrated expression will be:

(1.1.37)

where is the total extraterrestrial solar radiation incident on horizontal surface during a day ( ).

The integration of Eq. (1.1.36) can be also performed between hour angles and to estimate the extraterrestrial solar radiation on a horizontal surface for a certain hour period. The formula can be expressed as:

(1.1.38)

where is the extraterrestrial solar radiation incident on horizontal surface between certain hours period within a day ( ).

1.1.7 Atmospheric attenuation

The solar radiation is depleted due to several factors including geographical, astronomical, geometrical, physical, and meteorological factors. Astronomical factors are related to the solar constant as well as solar angles, mainly solar declination, hour angle, and sunshine’s hours. The geographic factors depend on the standard and local latitude as well as on the longitude [8]. The geometric factors are related to the slope of the surface and azimuth angle [9]. The physical factors are function of the moisture content and dust in the atmosphere, air molecules, and miscible gases as well as the thickness of ozone layer [10]. Meteorological factors are related to temperature, precipitation, and humidity [11].

The earth is surrounded by atmosphere that contains various gas constitutes and particles such as oxygen (O2), water vapor ( ), ozone , carbon dioxide , carbon monoxide ( ), dust, and clouds. Therefore, the solar radiation is depleted during its passage though the atmosphere before reaching the ground due to absorption, scattering, and cloud reflectance.

The degree of solar depletion depends on the length of the path and the characteristics of the crossed medium. It is assumed that the reduction in the radiation intensity with increasing the solar zenith angle is directly proportional to the increase of air mass. In solar calculation, the air mass is defined as the ratio of the path length through the atmosphere which beam radiation takes to the path length would be taken when the sun is directly overhead, as shown in Fig. 1.1.8. It is quantifying the reduction in the intensity of radiation as it passes through the atmosphere and is absorbed by air and dust; mathematically, it is expressed by:

(1.1.39)

Figure 1.1.8 Path length of beam radiation when sun is directly overhead and when it is tilted by zenith angle.

At sea level, the sun is overhead and the zenith angle ( ; thus air mass is equal to 1.

1.1.8 Terrestrial solar radiation

The radiation at the earth's surface varies widely due to atmospheric effects, latitude, the season of the year, and the time of day that reflects on the solar radiation received by solar collector. To evaluate the performance of the solar system, data of an average daily total solar radiation for each month in the year for the selected location are required. Fortunately, the required data are available either from meteorological stations or solar radiation maps as daily average total solar radiation incident on a horizontal surface per month, , , or monthly average clearness index, .

The monthly average clearness index is defined as the monthly average daily total solar radiation incident on a terrestrial horizontal surface to the monthly average daily total solar radiation incident on an extraterrestrial horizontal surface .

(1.1.40)

The daily clearness index can be also defined in general form as the ratio of the solar radiation on a specific day in a month to the extraterrestrial radiation for that day in the month, and it is represented mathematically as:

(1.1.41)

The data of are the total solar radiation incident on a terrestrial horizontal surface on a specific day in a specific month, which can be found from the available data. The value of can be calculated using Eq. (1.1.37).

The clearness index can be represented on hour’s bases; in the case of hourly clearance index, it relates the ratio of the solar radiation in a specific hour to the extraterrestrial radiation at that hour. The equation form is

(1.1.42)

where is the terrestrial solar radiation incident on horizontal surface by an hour period, and the value of can be calculated using Eq. (1.1.38).

The hourly values of radiation are important and required always to predict the performance of solar system; however, those values are directly not available. It can be found from the available daily average total solar radiation incident on a horizontal surface per month, using the below empirical correlations reported by Collares-Pereira et al. [12] and Liu et al. [13].

(1.1.43)

(1.1.44)

(1.1.45)

(1.1.46)

(1.1.47)

(1.1.48)

where relates the hourly total radiation to daily total radiation , relates the hourly diffuse radiation to daily diffuse radiation , is the hour angle at the midpoint of each hour, is the sunset hour angle in degree, and are constants evaluated using the above formula.

1.1.9 Total radiation on a tilted surface

Solar collectors are usually installed with a tilted angle, to minimize reflected losses and capture as much as possible incident solar radiation. The beam radiation incident on a horizontal is function of the solar zenith angle; however, the beam radiation incident on a tilted surface is function of the incident angle as shown in Fig. 1.1.9. Mathematically, the beam radiation incident on horizontal and tilted surfaces is:

(1.1.49)

(1.1.50)

where represents the beam radiation incident on a horizontal surface, , represents the beam radiation incident on a tilted surface, , and represents the beam radiation at normal incident, .

Figure 1.1.9 Beam radiation on horizontal and tilted surfaces.

The ratio of beam radiation of tilted surface to beam radiation on horizontal surface is expressed by a geometric factor known as beam radiation tilted factor (BRTF), , in the equation form:

(1.1.51)

Both and are determined from Eqs. (1.1.9) and (1.1.18), respectively. The beam component on a tilted surface can be found by

(1.1.52)

The optimum azimuth angle for flat-plate collectors is at at northern and southern hemispheres, respectively. Thus the incident angle in Eq. (1.1.18) can be reduced, and the BRTF is expressed as:

For northern hemisphere:

(1.1.53)

For southern hemisphere:

(1.1.54)

The total radiation incident on the absorber of a tilted flat-plate collector consists of three components: (1) beam radiation that is received by absorber directly from the sun without being scattered, (2) diffuse radiation which is received by the absorber after being scattered and changing its direction, and (3) ground-reflected radiation known also as albedo, which is the fraction of solar radiation incident on the ground and then reflected to absorber surface.

In equation form:

(1.1.55)

where indicates the total radiation on tilted surface, , and are the beam, diffuse, and ground-reflected components incident on a tilted surface, .

The beam component on a tilted surface can be found from Eq. (1.1.52). Following the assumption suggested by [14] and modified by [15] as mentioned in [4], that the combination of diffuse and ground-reflected radiation is isotropic, the total of the diffuse from the sky and the ground-reflected radiation on the tilted surface is the same regardless of orientation [4]. The total solar radiation on tilted surface can be found using the expression:

(1.1.56)

where represents the diffuse component on a horizontal surface, is the sum of beam and diffuse components on a horizontal surface, and is the ground-reflecting factor.

1.1.10 Estimation of daily and hourly beam and diffuse radiation on tilted surface

To estimate average total radiation on tilted surface radiation on a daily and hourly basis, various empirical correlations have been developed by several authors. Liu et al. [13] developed a correlation that relates the average monthly diffuse to average total radiation for a horizontal surface, and it is expressed in terms of clearance index.

(1.1.57)

Collares-Pereira et al. [12] developed another correlation that takes into account the sunset hour angle

(1.1.58)

More correlation was developed by Erbs et al. [16] which took into consideration the effect of seasons.

(1.1.59)

(1.1.60)

Since the monthly average daily will be given, and by using suitable correlation, the monthly average daily diffuse can be estimated, and the average beam radiation on horizontal surface can be evaluated.

(1.1.61)

Therefore, the monthly total radiation on a tilted surface will be expressed as:

(1.1.62)

where presents the total radiation on a tilted surface, , and are the beam and diffuse components incident on a horizontal surface, .

Origill et al. [17], Erbs et al. [16], and Reindl et al. [18] developed correlations that relate hourly diffuse radiation to hourly total one on a horizontal surface radiation for a horizontal. The developed correlations by [17] and [16] are represented, respectively, by the following equations:

(1.1.63)

(1.1.64)

The steps to estimate the values of radiation on a tilted surface from the mean daily values in a month are as follows:

1. The total monthly average radiation on a horizontal surface ( can be obtained, as it is available in different resources; usually, the given value is assumed to be for the central day of the month (the day in the middle of the month).

2. Interpolate to calculate the value of the total radiation on a horizontal surface ( for required specific day (day in the question).

3. Determine the clearness index using the value of total radiation on a horizontal surface and the extraterrestrial radiation

4. Choose the appropriate model that relates the diffuse to total radiation on a horizontal surface , and evaluate the diffuse radiation .

5. With and , the beam component on the horizontal surface can be evaluated .

6. Transform the daily radiation values to hourly values through the correlations given in Eqs. (1.1.45) and (1.1.46).

7. Calculate hourly total, hourly diffuse, and hourly beam radiation on horizontal surface.

8. Project the radiation of the horizontal surface on the tilted surface by means of a radiation isotropic model.

(1.1.65)

where is the total hourly radiation incident on a tilted surface .

1.1.11 Conclusion

In this chapter, the structure of sun and nature of sunlight have been presented, along with the main definitions and solar nomenclature, in order to make the reader familiar with solar radiation terminology. The chapter also discussed the solar angles and the sun path diagram as those angles can describe the position of the sun relative to a plane relative to the earth.

This chapter also includes the characteristics of solar radiation outside and inside the earth’s atmosphere. It discusses the extraterrestrial radiation on normal and horizontal surfaces, the atmosphere attenuation, and the terrestrial solar radiation. Furthermore, the methods and steps to evaluate the terrestrial radiation on the tilted surface have been discussed in this chapter.

References

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Chapter 1.2

Development of solar thermal energy systems

Bashria A.A. Yousef¹, Ali Radwan¹,², Abdul Ghani Olabi¹,³ and Mohammad Ali Abdelkareem¹,⁴,    ¹Sustainable and Renewable Energy Engineering Department, College of Engineering, University of Sharjah, Sharjah, United Arab Emirates,    ²Mechanical Power Engineering Department, Mansoura University, El-Mansoura, Egypt,    ³School of Engineering and Applied Science, Mechanical Engineering and Design, Aston University, School of Engineering and Applied Science, Aston Triangle, Birmingham, United Kingdom,    ⁴Faculty of Engineering, Minia University, Elminia, Egypt

Abstract

The attention toward clean energy sources has increased more and more recently, due to the increasing concern about the environment and the limitation of conventional energy resources. Thus a secure, environmentally friendly, and efficient energy source is needed now more than ever for a sustainable and healthy society. This chapter presents different types of solar thermal technology. It starts by introducing historical background of solar application, followed by an overview of solar thermal energy systems. The chapter presents the different types of non-concentrating solar and concentrated solar collectors.

Keywords

Flat-plate collector; evacuated collectors; compound parabolic collector; parabolic trough; linear Fresnel collectors; solar tower; parabolic dish

1.2.1 Historical background

The sun is the only star of our solar system, and it is sited at its center. Due to the gravity of sun, the solar system is held together. The earth and other planets, asteroids, comets, and tiny bits of space debris revolve around the sun. Radiant light and heat from sun support all life on earth via photosynthesis and drive the earth’s climate and weather.

A long time before the invention of modern solar thermal technologies, heat from sun was utilized by many ancient civilizations. One of the oldest applications of solar heat was the burning of the Roman fleet in the bay of Syracuse in 216 BC by Archimedes, the greatest Greek technologist (287–212 BC). According to Plutarch, the Greek biographer and philosopher (46–119 AD), Archimedes reflected the sun’s rays onto the Roman fleet and flame them.

This event was hot topic for scientists and medieval chroniclers over a thousand years later, and they made references to this event and overstated the events with their details [1]. Whether or not Archimedes knew enough about optical science and sunlight concentration, he had written a book, On Burning Mirrors [2,3], which is known onl1y from references, since no copy survived [4].

Proclus Lycius Greek Philosopher (412–485 AD) used the same techniques of Archimedes burning mirrors in Constantinople and burned the war fleet of the enemies surrounding Byzance [2]. The burning mirrors techniques described by the Polish mathematician Vitelio (13th century) in volume 5 of his book Optics, as he stated that [1]: "The burning glass of Archimedes composed of 24 mirrors, which conveyed the rays of the sun into a common focus and produced an extraordinary degree of heat." Many historians believed that Archimedes arranged the shields of soldiers in a large parabola to focus the sun’s rays into a common point on a ship, which emphasized the power of solar radiation (see Fig. 1.2.1).

Figure 1.2.1 Concept of archimedes burning mirrors.

After many years of continuous experimental studies, Thomas Newcomen (1664–1729) completed the development of the first steam engine in 1712 [5], which was improved by James Watt (1736–1819) by separating steam and the condensing chambers (Fig. 1.2.2). This was the start of industrial revolution, which was associated with the use of more coal and unfortunately created environmental pollution. Many scientists were investigating the possibility of using renewable energies that were the establishment of new solar energy era, which started about the 18th century.

Figure 1.2.2 First steam engine invented by Newcomen and modified by Watt.

Despite the difficulty of constructing concentrating collectors, the first application of solar energy was constructed in the 18th century. Solar furnaces were the first large-scale application in 1774, constructed by Lavoisier as shown in Fig. 1.2.3, and it is made from iron and glass concave mirrors for melting iron, copper, and other material. The furnace used a total of 1.52 m lens, and its temperature reached about 1750°C [4].

Figure 1.2.3 Solar furnace constructed by Lavoisier [6].

During the 19th century, more studies were conducted to apply solar energy in various industrial fields. The first scientist who worked on solar–thermal conversion devices was the pioneer August Mouchot. In 1864 and 1880, Mouchot constructed several steam engines driven by solar power and published the first book as well as many articles about the industrial use of solar heat. Mouchot’s parabolic collector used to the drive steam engine and operate the printing press was presented at the 1878 International Exhibition in Paris. Another solar machine for Mouchot was set up in Algeria in 1878, and it was made of truncated cone reflector consisting of silver-plated metal plates, 5.4 m diameter, and 18.6 m² collecting area [7].

In the same period, a French engineer Abel Pifre (1857–1928) used a parabolic reflector made of small mirrors to develop solar power printing press. An American engineer John Ericson (1803–1889) developed a solar steam engine using parabolic troughs and built eight systems using water and air as heat transfer fluids [8].

During the 20th century, several solar thermal collectors were developed. In 1901, A.G. Eneas used a focusing collector of 10 m diameter and 1788 mirrors to generate steam to power a water pumping system at a California Farm [9]. In 1904, Portuguese priest and scientist, Father Himalaya constructed an advanced large solar furnace with a parabolic horn collector. In 1912, Frank Shuman and C.V. Boys used 62-m-long parabolic cylinders to focus sunlight into a long absorber tube, the total area of the cylinders being 1200 m², and developed a large pumping plant in Egypt. The solar system developed an average of 37–45 kW for 5 hours [10].

Continuous developments and construction of solar thermal systems took place during the last 50 years using focusing collectors to heat working fluid for power generation. The solar thermal technologies used are central receiver system that includes heliostats and tower, distributed receiver technology which includes parabolic dishes, Fresnel lenses, and parabolic troughs. Recently, the most mature and commercial technologies are solar tower and parabolic trough.

Other areas of interest, for solar thermal, are house heating and hot water that began a long time before the invention of modern solar thermal technologies, when ancient Greeks designed their houses to use solar energy for heating their dwellings. They used attics and window patterns to collect solar heat in winter and avoid it during the summer.

In the 18th century, Horace Bénédict de Saussure built simple solar water heaters made of boxes with a black bottom and covered with glass. In 1891, the first commercial solar water heater was invented by Clarence Kemp in the United States, and within 5 years, about one-third of the houses installed solar water heater system. In 1900, William Bailey developed the first thermosyphon system which was more ergonomic and compact with a great improvement of early