NAME: AMIR ABUL KALAM DEPARTMENT: NANOPHYSICS SUBJECT: ENERGY HERVESTING DEVICES STUDENT’S ID:

SOLAR ENERGY BASIC PRINCIPLE Electromagnetic Radiation Capture Electromagnetic Source Electricity or Heating

AVAILABLE SOLAR RESOURCES Geographic Location Time of Day Season Local Landscape Local Weather

DIFFUSE & DIRECT SUNLIGHT Air Molecules Water Vapor Clouds Dust Pollutants

MEASURING SUNLIGHT Amount of solar energy available at a given location during the different times of year. It depends on different factors like, Latitude, climate and other conditions. MEASURING SUNLIGHT Total radiation on horizontal surface or Total amount of radiation on a surface tracking the sun. Tracking device and solar panel are the two main components. It is expressed by KWh/m 2 or W/m 2

SOLAR PANEL solar panel is a device that collects and converts solar energy into electricity or heat. WORKING PRINCIPLE sun's energy excites the atoms in a silicon layer between two protector panels. Electrons from these excited atoms form an electric current, which can be used by external devices.

APPLICATION

SOLAR THERMAL ENERGY Solar thermal energy (or STE) is a technology for harnessing solar energy for heat. SOLAR THERMAL COLLECTOR Low Medium High

LOW TEMPERATURE COLLECTOR Low temperature collectors are flat plates generally used to heat swimming pools.

HIGH TEMPERATURE COLLECTOR High temperature collectors concentrate sunlight using mirrors or lenses and are generally used for electric power production.

Collector types Various types of solar collectors can be used: Unglazed absorbers This is the simplest type of solar collector, consisting of a black plastic matting that is often used to heat water in swimming pools in order to reduce their operating costs. They are cheaper than a fossil-fuel boiler and achieve ­temperatures of 30 – 40 °C. Flat plate collectors The metal solar absorber is fitted in a casing that reduces the rate of heat loss thanks to thermal insulation and a glass pane. Flat plate collectors generally operate in the temperature range 60 – 90 °C. Air heater solar collectors This is a special kind of flat plate collector. Air is heated and normally used to heat buildings immediately, without having to be stored in the interim. The heated air can also be used to dry agricultural products. The use of air-water heat exchangers allows you to heat water, e.g. tap water.

Evacuated tube collectors Even higher temperatures and degrees of efficiency are achieved with evacuated tube collectors, in which the level of heat loss is significantly reduced thanks to high negative pressure in the glass tubes. A collector is made up of several evacuated tubes. Thanks to the rotatable mounting for the individual tubes, the flat absorber plate in the glass tubes can be turned to the optimum position for sunlight. For this reason, evacuated tube collectors can also be deployed nearly horizontally on flat roofs. The individual tubes form a closed system that transfers heat through a frost-proof heat cycle to the domestic water supply.

FLAT PLATE COLLECTOR

EVACUATED TUBE COLLECTORS

PARABOLIC CONCENTRATE COLLECTOR

EFFICIENCY CURVE

THERMAL ENERGY STORAGE

Magnetic storage systems are an area where a lot of exciting development is currently occurring. However, a lot of development still needs to be done before any form of commercial implementation could be seen. Traditional systems store energy within capacitors and newer systems currently under development will potentially operate using superconducting materials and their magnetic fields to store energy. MAGNETIC

Thermal energy can be stored in two forms, by elevating the temperature of a substance or lowering it. The storage systems themselves can store heat in a variety of ways and using a large variety of materials depending on the application. As an example, heat can be stored as sensible heat through heating water, ceramic bricks, rocks & oil. Or alternatively the energy can be stored through latent heat by converting water into ice or paraffin from a wax to a liquid. The selection of the materials and whether storage is through latent heat or sensible heat is dependent on the temperature range and storage durations. THERMAL

Biological energy storage systems are still in their infancy and little information is available currently. Such technology works through exploring energy potential of molecules that are used to store energy in living organisms. A variety of molecules are of interest such as glucose, starch & fats. Currently efficiencies of such levels are low and further research is required for significant interest to develop in this area. BIOLOGICAL

MECHANICAL Compressed Air Storage System Pumped Hydro Storage System Flywheel Energy Storage System

Energy can be stored mechanically in a number of ways. The primary methods being compressed air, hydro storage and flywheels. Compressed air systems compress air into storage reservoirs (usually underground) during off peak hours and then later released through a gas turbine generator. Suitable reservoirs for such systems are through the use of natural caverns, old oil wells and porous rock formations. Such systems are comparable to hydro storage. COMPRESSED AIR STORAGE SYSTEM

PUMPED HYDRO STORAGE SYSTEM Hydro storage systems are perhaps one of the most commonly used systems of energy storage with all hydro power stations working on this principle. However, on demand storage can also be achieved by using pumps to drive water up to an elevated reservoir and drain it through turbines to release power.

Flywheels store kinetic energy through spinning a relatively large mass. These systems have long been used to smooth out the power output from engines. In fact almost every reciprocating engine utilizes a flywheel. However, new uses for flywheels are emerging by connecting them to electric motor/generators to smooth out peak energy demands. In such implementations, electrical supply equipment can be sized for base load supply rather than sizing to cope with peak loads. FLYWHEEL ENERGY STORAGE SYSTEM

Chemical storage is perhaps one of the most well-known systems of energy storage since many of us carry such devices in our pockets as part of our mobile phones. While Lithium Ion, & Lead Acid batteries are what we most commonly see, storage exists in a variety of other forms. For example Sodium Sulphur batteries which operate at high temperatures (250 to 350°C) offer considerably better capacities. Chemical storage also comprises of storing energy as Hydrogen which is generated easily through electrolysis of water. Hydrogen can then be used to generate heat (through direct burning) or to generate electricity through the use of a fuel cell. CHEMICAL

SOLAR THERMAL ENERGY

BASIC MECHANISM OF STE

FUTURE SCOPE OF STE

ADVANTAGES OF STE

DISADVANTAGES OF STE

LEVELIZED COST Since a solar power plant does not use any fuel, the cost consists mostly of capital cost with minor operational and maintenance cost. If the lifetime of the plant and the interest rate is known, then the cost per kWh can be calculated. This is called the levelized cost. For example, the fact sheet of the Andasol 1 project shows a total investment of 310 million euros for a production of 179 GWh a year. Since 179 GWh is 179 million kWh, the investment per kWh a year production is 310 / 179 = 1.73 euro.