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- 1. Renewable Energy Sources Renewable Energy Systems August 3, 2020 Hemachandra G Assistant Professor CMR Institute of Technology
- 3. Renewable Energy Sources Introduction Solar collectors are heat exchangers.
- 4. Renewable Energy Sources Introduction Solar collectors are heat exchangers. Absorbs the solar radiation, converts it into heat, and transfers this heat to a fluid (usually air, water, or oil).
- 5. Renewable Energy Sources Introduction Solar collectors are heat exchangers. Absorbs the solar radiation, converts it into heat, and transfers this heat to a fluid (usually air, water, or oil). The solar energy thus collected is carried from the circulating fluid either directly to the hot water or space conditioning equipment, or to a thermal energy storage tank from which can be drawn for use at night and/or cloudy days.
- 7. Renewable Energy Sources Solar Collectors Solar collectors can be classified according to their collecting characteristics, the way in which they are mounted and the type of transfer fluid they use.
- 8. Renewable Energy Sources Solar Collectors Solar collectors can be classified according to their collecting characteristics, the way in which they are mounted and the type of transfer fluid they use. Collecting characteristics
- 9. Renewable Energy Sources Solar Collectors Solar collectors can be classified according to their collecting characteristics, the way in which they are mounted and the type of transfer fluid they use. Collecting characteristics A non-concentrating or flat plate collector is one in which the absorbing surface for solar radiations is essentially flat with no means for concentrating the incoming solar radiation.
- 10. Renewable Energy Sources Solar Collectors Solar collectors can be classified according to their collecting characteristics, the way in which they are mounted and the type of transfer fluid they use. Collecting characteristics A non-concentrating or flat plate collector is one in which the absorbing surface for solar radiations is essentially flat with no means for concentrating the incoming solar radiation. A concentrating or focusing collector is one, which usually contains reflectors or employs other optical means to concentrate the energy falling on the aperture onto a heat exchanger of surface area smaller than the aperture.
- 14. Renewable Energy Sources Contd... Mounting A collector can be mounted to remain stationary, be adjustable as to tilt angle (measured from the horizontal) to follow the change in solar declination or be designed to track the sun.
- 15. Renewable Energy Sources Contd... Mounting A collector can be mounted to remain stationary, be adjustable as to tilt angle (measured from the horizontal) to follow the change in solar declination or be designed to track the sun. Tracking is done by employing either an equatorial mounting or an azimuth mounting, for the purpose of increasing the absorption of the daily solar irradiation.
- 16. Renewable Energy Sources Contd... Mounting A collector can be mounted to remain stationary, be adjustable as to tilt angle (measured from the horizontal) to follow the change in solar declination or be designed to track the sun. Tracking is done by employing either an equatorial mounting or an azimuth mounting, for the purpose of increasing the absorption of the daily solar irradiation. Types of fluid:
- 17. Renewable Energy Sources Contd... Mounting A collector can be mounted to remain stationary, be adjustable as to tilt angle (measured from the horizontal) to follow the change in solar declination or be designed to track the sun. Tracking is done by employing either an equatorial mounting or an azimuth mounting, for the purpose of increasing the absorption of the daily solar irradiation. Types of fluid: A collector will usually use either a liquid or a gas as the transfer fluid.
- 18. Renewable Energy Sources Contd... Mounting A collector can be mounted to remain stationary, be adjustable as to tilt angle (measured from the horizontal) to follow the change in solar declination or be designed to track the sun. Tracking is done by employing either an equatorial mounting or an azimuth mounting, for the purpose of increasing the absorption of the daily solar irradiation. Types of fluid: A collector will usually use either a liquid or a gas as the transfer fluid. The most common liquids are water or a water-ethylene glycol solution. The most common gas is air.
- 20. Renewable Energy Sources Flat-plate Collector Flat plate collectors are divided in three main groups according to how they are oriented:
- 21. Renewable Energy Sources Flat-plate Collector Flat plate collectors are divided in three main groups according to how they are oriented: Flat-plate collectors facing south at fixed tilt
- 22. Renewable Energy Sources Flat-plate Collector Flat plate collectors are divided in three main groups according to how they are oriented: Flat-plate collectors facing south at fixed tilt One-axis tracking flat-plate collectors with axis oriented north-south
- 23. Renewable Energy Sources Flat-plate Collector Flat plate collectors are divided in three main groups according to how they are oriented: Flat-plate collectors facing south at fixed tilt One-axis tracking flat-plate collectors with axis oriented north-south Two-axis tracking flat-plate collectors
- 24. Renewable Energy Sources Flat-plate collectors facing south at fixed tilt
- 26. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o .
- 27. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o . Data for a tilt of 0o , referred to as global horizontal solar radiation, show how much solar radiation is received by a horizontal surface such as a solar pond.
- 28. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o . Data for a tilt of 0o , referred to as global horizontal solar radiation, show how much solar radiation is received by a horizontal surface such as a solar pond. Maximum yearly solar radiation can be achieved using a tilt angle approx. equal to a site’s latitude.
- 29. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o . Data for a tilt of 0o , referred to as global horizontal solar radiation, show how much solar radiation is received by a horizontal surface such as a solar pond. Maximum yearly solar radiation can be achieved using a tilt angle approx. equal to a site’s latitude. To optimize performance in the winter, the collector can be tilted 15o greater than the latitude.
- 30. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o . Data for a tilt of 0o , referred to as global horizontal solar radiation, show how much solar radiation is received by a horizontal surface such as a solar pond. Maximum yearly solar radiation can be achieved using a tilt angle approx. equal to a site’s latitude. To optimize performance in the winter, the collector can be tilted 15o greater than the latitude. To optimize performance in the summer, the collector can be tilted 15o less than the latitude.
- 31. Renewable Energy Sources Contd... Five tilt angles from the horizontal: 0o , latitude minus 15o , latitude, latitude plus 15o , and 90o . Data for a tilt of 0o , referred to as global horizontal solar radiation, show how much solar radiation is received by a horizontal surface such as a solar pond. Maximum yearly solar radiation can be achieved using a tilt angle approx. equal to a site’s latitude. To optimize performance in the winter, the collector can be tilted 15o greater than the latitude. To optimize performance in the summer, the collector can be tilted 15o less than the latitude. Data for a tilt of 90o apply to collectors mounted vertically on south-facing walls and apply to south-facing windows for passive solar designs.
- 32. Renewable Energy Sources One-axis tracking flat-plate collectors with axis oriented north-south
- 34. Renewable Energy Sources Contd... Data are presented for four different axis tilt angles from the horizontal: 0o , latitude minus 15o , latitude, and latitude plus 15o .
- 35. Renewable Energy Sources Contd... Data are presented for four different axis tilt angles from the horizontal: 0o , latitude minus 15o , latitude, and latitude plus 15o . These trackers pivot on their single axis to track the sun, facing east in the morning and west in the afternoon.
- 36. Renewable Energy Sources Contd... Data are presented for four different axis tilt angles from the horizontal: 0o , latitude minus 15o , latitude, and latitude plus 15o . These trackers pivot on their single axis to track the sun, facing east in the morning and west in the afternoon. Large collectors can use an axis tilt angle of 0o to minimize collector height and wind force.
- 37. Renewable Energy Sources Contd... Data are presented for four different axis tilt angles from the horizontal: 0o , latitude minus 15o , latitude, and latitude plus 15o . These trackers pivot on their single axis to track the sun, facing east in the morning and west in the afternoon. Large collectors can use an axis tilt angle of 0o to minimize collector height and wind force. Small collectors can have their axis tilted up to increase the solar radiation on the collector.
- 38. Renewable Energy Sources Contd... Data are presented for four different axis tilt angles from the horizontal: 0o , latitude minus 15o , latitude, and latitude plus 15o . These trackers pivot on their single axis to track the sun, facing east in the morning and west in the afternoon. Large collectors can use an axis tilt angle of 0o to minimize collector height and wind force. Small collectors can have their axis tilted up to increase the solar radiation on the collector. Just as for the flat-plate fixed tilt collector, the yearly and seasonal solar radiation can be optimized by the choice of tilt angle.
- 39. Renewable Energy Sources Two-axis tracking flat-plate collectors
- 41. Renewable Energy Sources Contd... Data for two-axis trackers represent the maximum solar radiation at a site available to a collector.
- 42. Renewable Energy Sources Contd... Data for two-axis trackers represent the maximum solar radiation at a site available to a collector. Tracking the sun in both azimuth and elevation, these collectors keep the sun’s rays normal to the collector surface.
- 43. Renewable Energy Sources Flat Plate Collector Hot Water OUT/ Sealed Heat Endosure Glazing Sheet Foam or Aluminium Insulation Heat Absorbing Riser Tubes Heat Absorbing Backplate ColdWater IN /
- 44. Renewable Energy Sources Liquid-type Flat Plate Collector
- 46. Renewable Energy Sources Contd... Glazing: One or more covers of transparent material like glass, plastics, etc. Glazing may be left out for some low temperature applications.
- 47. Renewable Energy Sources Contd... Glazing: One or more covers of transparent material like glass, plastics, etc. Glazing may be left out for some low temperature applications. Glass which transmits shorter wavelength solar radiation, but blocks the longer wavelength radiation from the absorber.
- 48. Renewable Energy Sources Contd... Glazing: One or more covers of transparent material like glass, plastics, etc. Glazing may be left out for some low temperature applications. Glass which transmits shorter wavelength solar radiation, but blocks the longer wavelength radiation from the absorber. Absorber: A plate with tubes or passages attached to it for the passage of working fluid. The absorber is usually painted flat black or electroplated with a selective absorber.
- 49. Renewable Energy Sources Contd... Glazing: One or more covers of transparent material like glass, plastics, etc. Glazing may be left out for some low temperature applications. Glass which transmits shorter wavelength solar radiation, but blocks the longer wavelength radiation from the absorber. Absorber: A plate with tubes or passages attached to it for the passage of working fluid. The absorber is usually painted flat black or electroplated with a selective absorber. Header or manifolds: To facilitate the flow or heat transfer fluid.
- 50. Renewable Energy Sources Contd... Glazing: One or more covers of transparent material like glass, plastics, etc. Glazing may be left out for some low temperature applications. Glass which transmits shorter wavelength solar radiation, but blocks the longer wavelength radiation from the absorber. Absorber: A plate with tubes or passages attached to it for the passage of working fluid. The absorber is usually painted flat black or electroplated with a selective absorber. Header or manifolds: To facilitate the flow or heat transfer fluid. Insulation: To minimise heat loss from the back and the sides.
- 51. Renewable Energy Sources Air type collectors
- 52. Renewable Energy Sources Air type collectors
- 53. Renewable Energy Sources Air type collectors Air type collectors are more commonly used for agricultural drying and space heating applications.
- 54. Renewable Energy Sources Air type collectors Air type collectors are more commonly used for agricultural drying and space heating applications. Their basic advantages are low sensitivity to leakages and no need for an additional heat exchanger for drying and space heating applications.
- 55. Renewable Energy Sources Air type collectors Air type collectors are more commonly used for agricultural drying and space heating applications. Their basic advantages are low sensitivity to leakages and no need for an additional heat exchanger for drying and space heating applications. However, because of the low heat capacity of the air and the low convection heat transfer coefficient between the absorber and the air, a larger heat transfer area and higher flow rates are needed.
- 56. Renewable Energy Sources Air type collectors Air type collectors are more commonly used for agricultural drying and space heating applications. Their basic advantages are low sensitivity to leakages and no need for an additional heat exchanger for drying and space heating applications. However, because of the low heat capacity of the air and the low convection heat transfer coefficient between the absorber and the air, a larger heat transfer area and higher flow rates are needed. Figure shows some common configurations of air heating collectors.
- 57. Renewable Energy Sources Air type collectors Air type collectors are more commonly used for agricultural drying and space heating applications. Their basic advantages are low sensitivity to leakages and no need for an additional heat exchanger for drying and space heating applications. However, because of the low heat capacity of the air and the low convection heat transfer coefficient between the absorber and the air, a larger heat transfer area and higher flow rates are needed. Figure shows some common configurations of air heating collectors. Common absorber materials include corrugated Al or galvanised steel sheets, black metallic screens or simply any black painted surface.
- 58. Renewable Energy Sources Air-type Flat Plate Collector Some common configurations of air heating collectors
- 60. Renewable Energy Sources Contd... Unglazed, transpired solar air collector offers a low-cost opportunity for some applications such as preheating of ventilation air and agricultural drying and curing.
- 61. Renewable Energy Sources Contd... Unglazed, transpired solar air collector offers a low-cost opportunity for some applications such as preheating of ventilation air and agricultural drying and curing. Such collectors consist of perforated absorber sheets that are exposed to sun and through which air is drawn.
- 62. Renewable Energy Sources Contd... Unglazed, transpired solar air collector offers a low-cost opportunity for some applications such as preheating of ventilation air and agricultural drying and curing. Such collectors consist of perforated absorber sheets that are exposed to sun and through which air is drawn. The perforated absorber sheets are attached to the vertical walls, which are exposed to the sun.
- 63. Renewable Energy Sources Contd... Unglazed, transpired solar air collector offers a low-cost opportunity for some applications such as preheating of ventilation air and agricultural drying and curing. Such collectors consist of perforated absorber sheets that are exposed to sun and through which air is drawn. The perforated absorber sheets are attached to the vertical walls, which are exposed to the sun. The most important components, whose properties determine the efficiency of solar thermal collectors, are glazing and absorber.
- 64. Renewable Energy Sources Concentrating or focusing Collector
- 65. Renewable Energy Sources Concentrating or focusing Collector It uses mainly beam radiation.
- 66. Renewable Energy Sources Concentrating or focusing Collector It uses mainly beam radiation. Concentrating, or focusing, collectors intercept direct radiation over a large area and focus it onto a small absorber area.
- 67. Renewable Energy Sources Concentrating or focusing Collector It uses mainly beam radiation. Concentrating, or focusing, collectors intercept direct radiation over a large area and focus it onto a small absorber area. These collectors can provide high temperatures more efficiently than flat-plate collectors, since the absorption surface area is much smaller.
- 68. Renewable Energy Sources Concentrating or focusing Collector It uses mainly beam radiation. Concentrating, or focusing, collectors intercept direct radiation over a large area and focus it onto a small absorber area. These collectors can provide high temperatures more efficiently than flat-plate collectors, since the absorption surface area is much smaller. However, diffused sky radiation cannot be focused onto the absorber.
- 69. Renewable Energy Sources Concentrating or focusing Collector It uses mainly beam radiation. Concentrating, or focusing, collectors intercept direct radiation over a large area and focus it onto a small absorber area. These collectors can provide high temperatures more efficiently than flat-plate collectors, since the absorption surface area is much smaller. However, diffused sky radiation cannot be focused onto the absorber. Most concentrating collectors require mechanical equipment that constantly orients the collectors toward the sun and keeps the absorber at the point of focus.
- 70. Renewable Energy Sources Disadvantages in Focusing collector
- 71. Renewable Energy Sources Disadvantages in Focusing collector Only beam component is collected in case of focusing collectors because diffuse component cannot be reflected.
- 72. Renewable Energy Sources Disadvantages in Focusing collector Only beam component is collected in case of focusing collectors because diffuse component cannot be reflected. Additional requirement of maintenance particularly to retain the quality of reflecting surface against dirt, weather, oxidation etc.
- 73. Renewable Energy Sources Disadvantages in Focusing collector Only beam component is collected in case of focusing collectors because diffuse component cannot be reflected. Additional requirement of maintenance particularly to retain the quality of reflecting surface against dirt, weather, oxidation etc. Non-uniform flux on the absorber whereas flux in flat-plate collector is uniform.
- 74. Renewable Energy Sources Disadvantages in Focusing collector Only beam component is collected in case of focusing collectors because diffuse component cannot be reflected. Additional requirement of maintenance particularly to retain the quality of reflecting surface against dirt, weather, oxidation etc. Non-uniform flux on the absorber whereas flux in flat-plate collector is uniform. Additional optical losses such as reflectance loss and the intercept loss, so they introduce additional factors in energy balances.
- 75. Renewable Energy Sources Flat plate Collector
- 76. Renewable Energy Sources Flat plate Collector
- 77. Renewable Energy Sources Flat plate Collector
- 78. Renewable Energy Sources Evacuated Tube Collector
- 79. Renewable Energy Sources Evacuated Tube Collector
- 81. Renewable Energy Sources Classification There are different types of concentrating or focusing collector depending upon the concentrator and receiver geometries.
- 82. Renewable Energy Sources Classification There are different types of concentrating or focusing collector depending upon the concentrator and receiver geometries. These are as follows:
- 83. Renewable Energy Sources Classification There are different types of concentrating or focusing collector depending upon the concentrator and receiver geometries. These are as follows: 1 Cylindrical parabolic collector/Parabolic trough system. 2 Parabolic dish. 3 Mirror Strip Reflector 4 Fresnel Lens Collector 5 Compound parabolic collector 6 Central receiver collector/Power tower.
- 84. Renewable Energy Sources Cylindrical parabolic collector In order to deliver high temperatures with good efficiency a high performance solar collector is required.
- 85. Renewable Energy Sources Cylindrical parabolic collector In order to deliver high temperatures with good efficiency a high performance solar collector is required. Systems with light structures and low cost technology for process heat applications up to 400o C could be obtained with parabolic trough collectors (PTCs).
- 86. Renewable Energy Sources Cylindrical parabolic collector In order to deliver high temperatures with good efficiency a high performance solar collector is required. Systems with light structures and low cost technology for process heat applications up to 400o C could be obtained with parabolic trough collectors (PTCs). PTCs can effectively produce heat at temperatures between 50o C and 400 o C.
- 87. Renewable Energy Sources Cylindrical parabolic collector In order to deliver high temperatures with good efficiency a high performance solar collector is required. Systems with light structures and low cost technology for process heat applications up to 400o C could be obtained with parabolic trough collectors (PTCs). PTCs can effectively produce heat at temperatures between 50o C and 400 o C. PTCs are made by bending a sheet of reflective material into a parabolic shape.
- 88. Renewable Energy Sources Cylindrical parabolic collector In order to deliver high temperatures with good efficiency a high performance solar collector is required. Systems with light structures and low cost technology for process heat applications up to 400o C could be obtained with parabolic trough collectors (PTCs). PTCs can effectively produce heat at temperatures between 50o C and 400 o C. PTCs are made by bending a sheet of reflective material into a parabolic shape. A metal black tube, covered with a glass tube to reduce heat losses, is placed along the focal line of the receiver.
- 90. Renewable Energy Sources The surface of the receiver is typically plated with selective coating that has a high absorption for solar radiation, but a low emittance for thermal radiation loss.
- 91. Renewable Energy Sources The surface of the receiver is typically plated with selective coating that has a high absorption for solar radiation, but a low emittance for thermal radiation loss. When the parabola is pointed towards the sun, parallel rays incident on the reflector are reflected onto the receiver tube.
- 92. Renewable Energy Sources The surface of the receiver is typically plated with selective coating that has a high absorption for solar radiation, but a low emittance for thermal radiation loss. When the parabola is pointed towards the sun, parallel rays incident on the reflector are reflected onto the receiver tube. It is sufficient to use a single axis tracking of the sun and thus long collector modules are produced.
- 93. Renewable Energy Sources The surface of the receiver is typically plated with selective coating that has a high absorption for solar radiation, but a low emittance for thermal radiation loss. When the parabola is pointed towards the sun, parallel rays incident on the reflector are reflected onto the receiver tube. It is sufficient to use a single axis tracking of the sun and thus long collector modules are produced. The collector can be orientated in an east-west direction, tracking the sun from north to south, or orientated in a north-south direction and tracking the sun from east to west.
- 95. Renewable Energy Sources Contd... Par abolic Shaped Reflective Trough Reflective Coating or Mirrors E /,0· Rotational W Axis Fuid IN I I I I I I / / / / / r�"-/-- Collector Supports Fluid Out --
- 99. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector.
- 100. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector. It tracks the sun, concentrating solar energy onto a receiver located at the focal point of the dish.
- 101. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector. It tracks the sun, concentrating solar energy onto a receiver located at the focal point of the dish. The dish structure must track fully the sun to reflect the beam into the thermal receiver.
- 102. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector. It tracks the sun, concentrating solar energy onto a receiver located at the focal point of the dish. The dish structure must track fully the sun to reflect the beam into the thermal receiver. The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid.
- 103. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector. It tracks the sun, concentrating solar energy onto a receiver located at the focal point of the dish. The dish structure must track fully the sun to reflect the beam into the thermal receiver. The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid. Fluid in tum runs the turbine and generate a power.
- 104. Renewable Energy Sources Contd... A parabolic dish reflector is a point-focus collector. It tracks the sun, concentrating solar energy onto a receiver located at the focal point of the dish. The dish structure must track fully the sun to reflect the beam into the thermal receiver. The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid. Fluid in tum runs the turbine and generate a power. The need to circulate heat transfer fluid throughout the collector field raises design issues such as piping layout, pumping requirements, and thermal losses
- 106. Renewable Energy Sources Contd... The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid.
- 107. Renewable Energy Sources Contd... The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid. The thermal energy can then be either converted into electricity using an engine-generator coupled directly to the receiver or transported through pipes to a central power conversion system.
- 108. Renewable Energy Sources Contd... The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid. The thermal energy can then be either converted into electricity using an engine-generator coupled directly to the receiver or transported through pipes to a central power conversion system. Parabolic dish systems can achieve temperatures in excess of 1500 o C.
- 109. Renewable Energy Sources Contd... The receiver absorbs the radiant solar energy, converting it into thermal energy in a circulating fluid. The thermal energy can then be either converted into electricity using an engine-generator coupled directly to the receiver or transported through pipes to a central power conversion system. Parabolic dish systems can achieve temperatures in excess of 1500 o C. Because the receivers are distributed throughout a collector field, like parabolic troughs, parabolic dishes are often called distributed receiver systems.
- 111. Renewable Energy Sources Advantages Because they are always pointing at the sun, they are the most efficient of all collector systems.
- 112. Renewable Energy Sources Advantages Because they are always pointing at the sun, they are the most efficient of all collector systems. They typically have concentration ratios in the range of 600-2000 and thus are highly efficient at thermal energy absorption and power conversion systems.
- 113. Renewable Energy Sources Advantages Because they are always pointing at the sun, they are the most efficient of all collector systems. They typically have concentration ratios in the range of 600-2000 and thus are highly efficient at thermal energy absorption and power conversion systems. They are modular collector and receiver units that can function either independently or as part of a larger system of dishes.
- 114. Renewable Energy Sources Advantages Because they are always pointing at the sun, they are the most efficient of all collector systems. They typically have concentration ratios in the range of 600-2000 and thus are highly efficient at thermal energy absorption and power conversion systems. They are modular collector and receiver units that can function either independently or as part of a larger system of dishes. Dish type Concentrating solar power (CSP) converts solar heat into electricity by focusing solar radiation onto a receiver containing a heat-engine known as a Stirling engine
- 115. Renewable Energy Sources Mirror Strip Reflector
- 116. Renewable Energy Sources Mirror Strip Reflector
- 117. Renewable Energy Sources Mirror Strip Reflector
- 118. Renewable Energy Sources Fresnel lens collector
- 119. Renewable Energy Sources Fresnel lens collector
- 120. Renewable Energy Sources Fresnel lens collector
- 121. Renewable Energy Sources Fresnel lens collector
- 122. Renewable Energy Sources Fresnel lens collector
- 124. Renewable Energy Sources Contd... Fresnel lenses are used as solar concentrators since they offer high optical efficiency along with minimal weight and low cost.
- 125. Renewable Energy Sources Contd... Fresnel lenses are used as solar concentrators since they offer high optical efficiency along with minimal weight and low cost. Though Fresnel lens concentrators have been used in solar energy concentration systems since 1960’s.
- 126. Renewable Energy Sources Contd... Fresnel lenses are used as solar concentrators since they offer high optical efficiency along with minimal weight and low cost. Though Fresnel lens concentrators have been used in solar energy concentration systems since 1960’s. The linear Fresnel reflector is a series of mirrors that arranged in different angles to fulfil the concentration function.
- 127. Renewable Energy Sources Compound parabolic collector
- 128. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector.
- 129. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector. It is a non-focusing type.
- 130. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector. It is a non-focusing type. Compound parabolic concentrators can accept incoming radiation over a relatively wide range of angles.
- 131. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector. It is a non-focusing type. Compound parabolic concentrators can accept incoming radiation over a relatively wide range of angles. It has a trough like arrangement with two parabolic mirrors.
- 132. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector. It is a non-focusing type. Compound parabolic concentrators can accept incoming radiation over a relatively wide range of angles. It has a trough like arrangement with two parabolic mirrors. Because of this arrangement, it collects both beam & diffuse radiation.
- 133. Renewable Energy Sources Compound parabolic collector It is also called CPC or wins ton collector. It is a non-focusing type. Compound parabolic concentrators can accept incoming radiation over a relatively wide range of angles. It has a trough like arrangement with two parabolic mirrors. Because of this arrangement, it collects both beam & diffuse radiation. CPCs are usually covered with glass to avoid dust and other materials from entering the collector and thus reducing the reflectivity of its walls.
- 134. Renewable Energy Sources Compound Parabolic collector
- 135. Renewable Energy Sources Compound Parabolic collector The orientation of a CPC collector is related to its acceptance angle (θc).
- 136. Renewable Energy Sources Compound Parabolic collector The orientation of a CPC collector is related to its acceptance angle (θc). Also depending on the collector acceptance angle, the collector can be stationary or tracking.
- 137. Renewable Energy Sources Compound Parabolic collector The orientation of a CPC collector is related to its acceptance angle (θc). Also depending on the collector acceptance angle, the collector can be stationary or tracking. A CPC concentrator can be orientated with its long axis along either the north-south or the east-west direction and its aperture is tilted directly towards the equator at an angle equal to the local latitude.
- 138. Renewable Energy Sources Compound Parabolic collector The orientation of a CPC collector is related to its acceptance angle (θc). Also depending on the collector acceptance angle, the collector can be stationary or tracking. A CPC concentrator can be orientated with its long axis along either the north-south or the east-west direction and its aperture is tilted directly towards the equator at an angle equal to the local latitude. As the acceptance angle of the concentrator along its long axis is wide, seasonal tilt adjustment is not necessary.
- 139. Renewable Energy Sources Compound Parabolic collector
- 140. Renewable Energy Sources Compound Parabolic collector
- 141. Renewable Energy Sources Compound Parabolic collector
- 142. Renewable Energy Sources Compound Parabolic collector
- 145. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel.
- 146. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity.
- 147. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows:
- 148. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure.
- 149. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure. 2 It must withstand temperature up to 200o C.
- 150. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure. 2 It must withstand temperature up to 200o C. 3 It must withstand many temperature cycles over ±40oC.
- 151. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure. 2 It must withstand temperature up to 200o C. 3 It must withstand many temperature cycles over ±40oC. 4 It must withstand many cycles of low to high relative humidity.
- 152. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure. 2 It must withstand temperature up to 200o C. 3 It must withstand many temperature cycles over ±40oC. 4 It must withstand many cycles of low to high relative humidity. 5 It must not chalk, fade, or chip.
- 153. Renewable Energy Sources Absorptive Coatings Many varieties of absorptive coating are being used, ranging from flat black paint to baked enamel. Flat black absorber coatings have high absorptivity. Specification requirement of an absorber coating for a flat plate collector is as follows: 1 It must not degrade under ultraviolet exposure. 2 It must withstand temperature up to 200o C. 3 It must withstand many temperature cycles over ±40oC. 4 It must withstand many cycles of low to high relative humidity. 5 It must not chalk, fade, or chip. 6 It must not be so thick that heat conduction through the paint to the metal absorber is impeded.
- 155. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers.
- 156. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers. Following are its important functions:
- 157. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers. Following are its important functions: 1 It must reduce convective losses from the absorber plate.
- 158. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers. Following are its important functions: 1 It must reduce convective losses from the absorber plate. 2 It must suppress radiative heat losses from the absorber plate.
- 159. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers. Following are its important functions: 1 It must reduce convective losses from the absorber plate. 2 It must suppress radiative heat losses from the absorber plate. 3 It must protect the absorber from the elements and from excessive UV exposures.
- 160. Renewable Energy Sources Glazing One or more sheets of glass or other diathermanous (radiation transmitting) material is used as transparent covers. Following are its important functions: 1 It must reduce convective losses from the absorber plate. 2 It must suppress radiative heat losses from the absorber plate. 3 It must protect the absorber from the elements and from excessive UV exposures. 4 A glazing material must be resistant to UV radiation.
- 162. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials:
- 163. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant.
- 164. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism.
- 165. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism. 3 They must be resistant to significant temperature shock.
- 166. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism. 3 They must be resistant to significant temperature shock. 4 Sudden rain will cause rapid overall limb changes. A leaf on a stagnant collector can cause high localized thermal stresses.
- 167. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism. 3 They must be resistant to significant temperature shock. 4 Sudden rain will cause rapid overall limb changes. A leaf on a stagnant collector can cause high localized thermal stresses. Thus, heat tempered glass is absolute necessity for outer collector glazing.
- 168. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism. 3 They must be resistant to significant temperature shock. 4 Sudden rain will cause rapid overall limb changes. A leaf on a stagnant collector can cause high localized thermal stresses. Thus, heat tempered glass is absolute necessity for outer collector glazing. Generally, plastic glazing can easily withstand the temperature shocks. Non-UV inhibited plastic
- 169. Renewable Energy Sources Glazing The following are the specification requirement of glazing materials: 1 They must be reasonably impact resistant. 2 Thin or no tempered glass panes are questionable because of the risk of damage from hail, birds, and vandalism. 3 They must be resistant to significant temperature shock. 4 Sudden rain will cause rapid overall limb changes. A leaf on a stagnant collector can cause high localized thermal stresses. Thus, heat tempered glass is absolute necessity for outer collector glazing. Generally, plastic glazing can easily withstand the temperature shocks. Non-UV inhibited plastic
- 171. Renewable Energy Sources Insulation Materials A solar flat plate collector must be insulated against excessive heat losses on its back side and on its edges as follows:
- 172. Renewable Energy Sources Insulation Materials A solar flat plate collector must be insulated against excessive heat losses on its back side and on its edges as follows: 1 Back side - 3 .5 inch of fiberglass insulation or 2 inch of foam insulation.
- 173. Renewable Energy Sources Insulation Materials A solar flat plate collector must be insulated against excessive heat losses on its back side and on its edges as follows: 1 Back side - 3 .5 inch of fiberglass insulation or 2 inch of foam insulation. 2 Side - 1 inch of fiberglass or 0.5 to 0.75 inch of foam insulation.
- 174. Renewable Energy Sources Insulation Materials A solar flat plate collector must be insulated against excessive heat losses on its back side and on its edges as follows: 1 Back side - 3 .5 inch of fiberglass insulation or 2 inch of foam insulation. 2 Side - 1 inch of fiberglass or 0.5 to 0.75 inch of foam insulation. The following are the specifications 1 Must withstand the maximum collector stagnation temperature rating (200oC) without damage. Foam materials shrink due to excessive heat.
- 175. Renewable Energy Sources Insulation Materials A solar flat plate collector must be insulated against excessive heat losses on its back side and on its edges as follows: 1 Back side - 3 .5 inch of fiberglass insulation or 2 inch of foam insulation. 2 Side - 1 inch of fiberglass or 0.5 to 0.75 inch of foam insulation. The following are the specifications 1 Must withstand the maximum collector stagnation temperature rating (200oC) without damage. Foam materials shrink due to excessive heat. 2 The maximum stagnation temperature must not cause evaporation or sublimation of substances in the insulating materials such as the binder of the fiberglass.
- 176. Renewable Energy Sources Heliostat electric generating plant
- 177. Renewable Energy Sources Schematic of Solar electric Generation wing electricity to a fluid tempera snel system, but 1 us, it cannot achi fthe parabolic di M ity from a cen and deliver it via heat-transfer fl pumping requi Solar pump Superheater Steam �-----1 generator Solar steam Solar Thermal Energy Collectors I Boiler Natural fuel Cooling tower Condenser Figure 3.15 Schematic of solar electric generation
- 178. Renewable Energy Sources Schematic of Solar Air Heating system A Pebble rock bed Auxiliar"'-____L....Hot air Building -<vCold '-----~.-------------;-::,_:-:- _ :-:: _ _ :-::--_::-:: _ _ :-::--_::-:: __:-::--_::-:: _ _ :-::--_;. _-i-------+--~-L Air : - - - - - - - - - - - - - - - ~Co~trol!! - - - - - - - - - - - - ~ : return - - - - - - - - - - - - - - - - - -- - - -- -- - - -- -- - - -·
- 179. Renewable Energy Sources Schematic of Active Hot water system hieved. e unit is ry limit cted but ugh the during , where ature-is e tank. angular . Small ifreeze special I. Collector(s) to capture solar energy. 2. Circulation system to move a fluid between the collectors to a storage tank 3. Storage tank 4. Backup heating system 5. Control system to regulate the overall system operation A typical active water heating system that exhibits effectiveness, reliability, and low maintena is shown in Figure 3.17. Sun rays � �i;lector �� sor s� ������ collector i Distelled water Solar controller Drainback tank with heat exchanger Pump Source: http://biddecor.blogspot.in/2015/02/solar-water-heating.html Figure 3.17 A typical hot water system Cold water +-
- 180. Renewable Energy Sources Schematic of Active Space Heating system
- 181. Renewable Energy Sources Schematic of Passive Hot water system 114 I Chapter 3 � � Insulated box Water distributed through the house Cold water
- 183. Renewable Energy Sources Rice solar dryer system 118 I Chapter 3 Cold air input Moist air out -1111111111111 -. Solar collector Rack IV Rack Ill Rack II Rack I Black pebbles stone t t t t t v t IV t Ill t II t I t t t t t t
- 184. Renewable Energy Sources Rock-bed solar dryer system
- 186. Renewable Energy Sources Assignment-2 Explain the configurations of the following solar thermal collectors (i) Air Flat Plate Collectors (FPC) (ii) Glazed FPC (iii) Unglazed FPC (iv) Unglazed Perforated FPC (v) Back-pass FPC (vi) FPC with Flat Reflectors (vii) Liquid Flat Plate Collector and (viii) Evacuated tube collectors (ETC). What are concentrating type solar collectors? Explain in detail the following concentrated solar thermal collectors (STC) (i) Compound Parabolic STC (ii) Fresnel STC (iii) Parabolic Trough STC (iii) Cylindrical Trough STC and (iv) Parabolic Dish STC. State the advantages and disadvantages of concentrated collectors over a flat plate collector