![Renewable Energy Resources [Solar Thermal Energy, Solar Pond]](https://cdn.slidesharecdn.com/ss_thumbnails/unit2resaktu-211020065235-thumbnail.jpg?width=560&fit=bounds)
More Related Content
Similar to Module-1 - solar applications.pptx (20)
Recently uploaded (20)
Module-1 - solar applications.pptx
- 2. Solar time It is the time based on the angular motion of the sun across the sky. With solar noon, the sun crosses the meridian of the observer. Solar time does not coincide with the local clock time. The concept of solar time is used in predicting the direction of sunrays relative to a point on the earth.
- 3. Conversion It is the time based on the 24-h clock, with 12:00 as the time that the sun is exactly due south. Solar time is location (longitude) dependent and is generally different from local clock time, which is defined by politically defined time zones and other approximations. Solar time is used extensively to define the rotation of the earth relative to the sun. The time used for calculating the hour angle (w) is the local apparent time.
- 4. LST This LST can be obtained from the standard time (ST) by making two corrections as given below: First correction arises because of the difference between the longitude of a location and the meridian on which the standard time is based. It has a correction of 4 min for every degree difference in longitude. The factor of 4 comes from the fact that earth rotates 1属 for every 4 min. The second correction is called the EOT.
- 5. LST
- 6. Calculate zenith angle of the sun at Lucknow (26.750 N) at 9:30 am on February 16, 2012. 53.914
- 7. Find the solar altitude angle at 2 h after local solar noon on 1 June 2012 for a city, which is located at 26.75属 N latitude. Moreover, find the sunrise and sunset hours and the day length. 6:48am, 17:12h
- 8. Calculate the hour angle at sunrise and sunset on June 21 and December 21 for a surface inclined at an angle of 10属 and facing due south (g = 0属). The surface is located in Mumbai (19属07' N, 72属51' E). If the day under consideration lies between March 21 and September 22, the hour angle at sunrise or sunset (wst) would be smaller in magnitude
- 9. For a city located at 80.50 longitudes, calculate the solar time on March 15,2011, at 10.30 AM Indian Standard time LST = = Standard time 賊 4 (LSTM Longitude of location (LLOL) + EOT LSTM = Local standard meridian time zone = 82.5属E (in India) EOT = 9.87 sin (2B) 7.67 sin (B + 78.7属); (in minutes) B = 360 (n 81)/365; (in degrees)
- 10. SOLAR ENERGY REACHING THE EARTHS SURFACE Solar radiation is electromagnetic radiation emitted by the sun. The sun is converting its mass into light particles called photons. Solar energy reaching the earth surface depends on several factors like geographical location etc.,
- 11. What happens to sunlight when it passes through atmosphere? absorption Energy converted to either electrical or heat energy scattering Gas molecules and small particles diffuse from the incoming solar radiation in different directions without any alteration to the wavelength of electromagnetic energy Reflection sunlight is redirected by 180属
- 12. Solar constant It is a measure of flux density and is the amount of incoming solar electromagnetic radiation per unit area that would be incident on a plane perpendicular to the rays at a distance of one AU. Between 1,353 and 1,395 W/m2 In India, the rate of solar radiation has been found to be 68 kWh/m2
- 13. Problems Associated with Harnessing Full Solar Energy Earth is displaced from the sun. Earth rotates about its polar axis. Thin shell of atmosphere that surrounds the earths surface.
- 15. SOLAR RADIATION OUTSIDE THE EARTHS SURFACE Energy radiation received from the sun, outside the earths atmospheres is essentially constant. Solar irradiance varies by 賊3.4% An instructional concept, which is often used in solar irradiance models, is the extraterrestrial solar irradiance falling on a horizontal surface.
- 16. Cosine effect Reduction of radiation by the cosine of the angle between the solar radiation and a surface normal is called the cosine effect. The cosine effect relates to the concept of extraterrestrial horizontal irradiance. The extraterrestrial solar irradiance falling on a surface parallel to the ground is
- 17. Solar Radiation on the Earths Surface (Solar Insolation) The rate at which solar energy reaches a unit area at the earth is called the solar irradiance or insolation. The units of measure for irradiance are watts per square metre (W/m2). The maximum solar irradiance value is used in system design to determine the peak rate of energy input into the system. United States, a peak insolation power at noon of 1 KW/m2 and 1.75 KW/m2 in India can be assumed as standard.
- 18. SOLAR ENERGY REACHING THE EARTHS SURFACE Beam radiation The solar radiation received on the earths surface without change of direction (without any attenuation) in line with sun. Diffuse radiation When solar radiation is subjected to attenuation and reaches the earths surface from all parts of the sky hemisphere. Global radiation Sum of beam and diffuse radiation
- 19. Air mass Air mass is a term normally used as a measure of the distance travelled by beam radiation through the earths atmosphere before it reaches a location at the earths surface. It is defined as the ratio of the mass of atmosphere through which the beam radiation passes to the mass of the atmosphere through which it will pass if the sun is directly overhead (i.e., at its Zenith). It has been proved that for location at sea level and zenith angles between 0属 and 70属, air mass is obtained as,
- 20. The power incident on a tilted surface
- 21. Relation between ITS, Ioh, and IO
- 23. Multipurpose utilization of solar energy
- 25. No need for pumps or motors Depends on the orientation, materials, and construction of a collector. Passive systems are particularly suited to the design of buildings and thermo siphoning solar hot water systems. In colder climates, a passive solar system can reduce heating costs by up to 40%. In hotter climates, it can reduce the absorption of solar radiation and thus reduce cooling costs.
- 26. Active System The most common active systems use pumps to circulate water or another heat absorbing fluid through solar collectors. These collectors are most commonly made of copper tubes bonded to a metal plate, painted black, and encapsulated within an insulated box covered by a glass panel or glazing.
- 27. To heat pools For pool heating and other applications where the desired temperature is less than 40属C, unglazed synthetic rubber materials are most commonly used. An active pumped system can be an open loop where the water is directly heated by the solar collector Closed loop where antifreeze or glycol mixture is heated before transferring its heat to the water by a heat exchanger. A popular design of the closed loop system is known as a drain back system. This freeze-proof design drains water back into a small holding tank when freezing temperatures occur.
- 28. Direct Thermal Applications The suns energy can be collected directly to create both high-temperature steam (greater than 100属C) and low-temperature heat (less than 100属C) for use in a variety of heat and power applications. LOW Low-temperature collectors are flat plates generally used to heat swimming pools. MEDIAM Medium-temperature collectors are also usually flat plates but are used for heating water or air for residential and commercial use. HIGH High-temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production.
- 29. Low-temperature Solar Thermal Systems Space heating for homes, offices, and greenhouses Domestic and industrial hot water Pool heating Desalination Solar cooking Crop drying Solar cooling Daylighting
- 30. Space heating for homes, offices, and greenhouses
- 31. Domestic and industrial hot water
- 32. Solar cooking
- 33. To heat pools
- 34. CROP DRYING
- 35. Solar cooling
- 36. Daylighting
- 37. Heating and Cooling System Design Considerations Solar and weather conditions in the locality Amount of solar radiation reaching the surface of a collector in a year Development of improved collector materials with good resistance to degradation from sun light Economic collector design Impact of a hot dry climate on the solar system
- 39. Solar thermoelectromechanical Conversion (Heat to Power)
- 41. Basic Rankine Cycle The pressure of saturated liquid leaving the condenser at state 1 is raised in an adiabatic, reversible process by the (ideal) pump to state 2, where it enters the vapour generator (also called a boiler or steam generator). The compressed liquid is heated at constant pressure (often called preheat) until it reaches a saturated liquid state 2' and then at constant temperature (and pressure) until all the liquid has vapourized to become saturated vapour at 3'.
- 42. Basic Rankine Cycle More heat is added to superheat the saturated vapour at constant pressure, and its temperature rises to state 3. The superheated vapour now enters an ideal expansion device (often a turbine) and expands in an adiabatic, reversible process to the low pressure maintained by the condenser indicated as state 4. The condenser converts the vapour leaving the turbine to liquid by extracting heat from it. Often during this expansion process, the vapour reaches saturation conditions and a mixture of saturated liquid and saturated vapour forms in the expander. The requirement to superheat the vapour from state 3' to 3 is defined by the amount of moisture that is permitted in the expander exhaust from state 4 to 4'.
- 43. Photovoltaic Conversion (Light to Power) Domestic lighting Street lighting Village electrification Water pumping Desalination of salty water Railway signals Powering of remote telecommunication repeater stations To meet electricity requirement
- 45. Solar heat storage Sensible heat storage - water, oil, rocks, bricks etc., Latent heat storage - salt, erythritol, citric acid, quick lime etc.,