1. New and Renewable Energy Systems  NEW -re-invented or revitalized as new technologies often using age-old principles but using new and more efficient, advanced engineering principles  RENEWABLE - Often renewed in a short span of time  SOLAR -Renewed on a daily cycle  WIND -At least on a seasonal cycle  BIOMASS -Within a few years

2. ALSO KNOWN AS Non conventional sources Alternative sources of energy MISNORMS AND MISCONCEPTIONS Appropriate technologies Rural Technologies SALIENT FEATURES Inexhaustible in nature Renewable Environmentally less harmful

3. DRAW BACKS High development cost Advanced engineering principles Skilled manpower requirement for assembly installation and maintenance Often deliver low quantities of output Diluted and dispersed form

4. CHARACTERISTICS Seasonality Variability Unreliability Irregularity What are the most common NRSE technologies pursued at present? Solar Wind Biomass Conversion – Biogas, Producer Gas, Briquettes etc. Geo Thermal Micro/Min Hydro (Major hydro being renewable but conventional) Ocean Related Energy Sources OTEC – Ocean thermal energy conversion Tidal Wave

5. SUN IS THE ENGINE OF LIFE Solar Radiation – Direct Solar Radiation, Diffused and Reflected Solar Radiation Two Main collection processes Technical Collection – Through properly designed technial devices Natural Collection – Through all other conversion processes such as: photosynthesis – bio mass, Evaporation and precipitation – hydro power, Convectional currents ( of air) cause wind etc. Tropical belt has enough sun shine to harness for the production of useful energy. The earth receives as much as 6000 times the entire demand of energy, the problem is to harness it in a cost effective manner. TWO BASIC PARAMETERS ARE IMPORTANT Solar irradiance Sun shine hours

6. Extra Terrestrial Irradiation 1.35kW/m ₂ sometime a figure of 1.37 kW /m 2 is also used. Spectral irradiance – important to analyze the behavior of conversion devices and for the design of conversion devices PERFORMANCE OF SOLAR CONVERSION SYSTEMS DEPEND ON Direct irradiance (Temporal and Geographic) Diffused irradiance Reflected irradiance Spectral distribution AVERAGE DATA IN SRI LANKA 1kW/m 2 irradiance on a bright sunny mid day 1780 kWh/m 2 per day or 5.6 kWh/m 2 per day

7. The Solar Spectral Distribution Solar spectral distribution closely follows the Planks Law of Black Body Radiation Plank’s Law:

9. Compare emissive Power of the Earth(at an average temperature of earth as 15 0 C with the Extraterrestrial Solar Spectrum Earth receives Solar Energy at shorter wave lengths and emits energy at longer Wave lengths.

10. Air Mass Ratio AMR or simply m Air Mass Ratio gives an indication of the distance the rays of the sun have to travel through the atmosphere before it reaches the surface. m-=1 when the sun is directly overhead

11. The Tilt of Earth With Respect to the Sun and the phenomenon of the seasons Summer in Northern Hemisphere is Winter in Southern Hemisphere and vice versa

12. An Alternative view of the Sun assuming it to move around the Earth for simplification With this definition, solar declination angle δ (The angle between the sun and the equator) is positive during summer of Northern hemisphere. That is it is positive from March 21 st to Sept. 21 st and negative during the rest of the period n is the Day number with January 1 st, n=1

13. Solar Declination

14. Latitude Angle Latitude angle (L) at any given point on earth’s surface is the line joining that point to the centre of earth is tilted above the equator above the equator. With this definition all the points on Northern hemisphere have positive latitude angles. Those on equator have zero latitude and those points on southern hemisphere have negative latitudes.

15. Definitions of the Key Latitudes of the Earth On the two equinox dates, ie. March 21 st and Sept. 21 st daytime is equal to night time everywhere on earth. The Solar noon on any day is the time at which sun is appearing at the local meridian (line of the local longitude)

16. Daylight Hours and Solar noon Daylight hours depend on solar declination and the latitude. In the Tropical belt at solar noon the sun will either be directly overhead depending on the date of the year or the sun will appear in the northern or southern sky. On June 21, the sun at solar noon is directly overhead at Tropic of Cancer at latitude 23.45. For all countries above tropic of Cancer, the sun will never be overhead. It will always appear on southern sky at noon. On Dec. 21, the sun at solar noon is directly overhead at Tropic of Capricorn at latitude -23.45. For all countries below tropic of Capricorn, the sun will never be overhead. It will always appear on northern sky at noon. On Dec. 21, all countries below Antarctic circle at -66.55° receive 24 hours of daylight and all countries above Arctic circle at 66.55°will be in dark for all 24 hours On June 21, all countries above Arctic circle at 66.55° receive 24 hours of daylight and all countries below Antarctic circle at -66.55° will be in dark for all 24 hours

17. Sun’s Position Position of sun at any time of day at any given location can be expressed by using two angles called azimuth angle and altitude angle. Altitude angle (β) is the angle between the sun and the local horizon directly beneath the sun. Azimuth angle (φs ) is the angle between local horizon beneath the sun and the due South (for Northern hemisphere) and the due North (for Southern hemisphere). Azimuth angles towards East (in the mornings ) are taken positive and towards West (in the afternoon and evenings) are negative.

18. Sun’s Position

19. Solar Time and Hour Angle Solar Time can be measured by the Hour Angle (H) It is the angle by which the sun must rotate before sun will be over the local meridian. H is positive before noon and negative after noon. H will be +15° at 11 am and -45° at 3 pm

24. Components of Solar Radiation on a Solar Collector Consists of three components : Direct – beam radiation Diffused radiation Reflected radiation Hence the global radiation consist of sum of al the above components while direct beam radiation is not so site specific diffused and reflected are very much site specific and only empirical data and indices are available.

47. Conclusion The collector should be tilted at an angle equal to the latitude angle of the location for maximum collection of solar energy over the year for a fixed tilt angle: this is known as polar mount. The maximum collection of solar energy over the year is for two axis tracking i.e. tracking the sun throughout the day and tracking the sun over the year depending on the declination of the sun. Single axis tracking is next best b y tracking the sun over the day from east to west.

48. SOLAR THERMAL APPLICATIONS Solar flat plate collectors Solar dryers Solar cookers Solar ovens Solar stills Solar ponds SEGS - solar concentrators (parabolic and dish) Solar refrigerators etc.

49. MOST COMMON APPLICATIONS ARE Solar flat plate collectors for hot water in domestic, hotel and industrial applications. MAIN FEATURES Collector plate - usually cu - selectively coated Firmly bonded water conduits Single or double glassing for green house effect Well insulated encasing Top and bottom water header Water tank well insulated and insulated pipe connections Auxiliary electric heater – if desired Primary and secondary fluids in special cases

51. Main Features Solar Dryer Solar Collector surface selectively coated or simply painted in a non reflective black coating generally large collector area using low cost polythene or glass Grain storage bins or trays placed in a chamber where grain or food is placed for drying in perforated trays to allow warm air to pass through Tall Chimney to expel humid air ( chimney effect ) Blackened rock bed heat storage (optional)

52. SOLAR CROP DRYING – FOR BETTER QUALITY GRAIN Clean Well dried Free from pests Reduced grain loss due to excessive breakages Prevents outer crust roasting and provides uniform slow moisture removal BASIC PRINCIPLES Green house effect Mass transfer

53. SOLAR DISTILLATION / DESALINATION Cheap efficient way of providing distilled or potable water Designs vary from small distilling units to large scale destination pants.