PV SYSTEMS, COMPONENTS DEVICES AND APPLICATIONS

Prabir Kumar Dash Scientist Solar Energy Centre prabir.dash@nic.in    Solar energy is the most abundant source of primary energy ( 7.2 x 1018 kJ/day) There are Two methods of harnessing solar energy ( photovoltaic & thermal) Method Of Direct Conversion Of Sunlight To Electricity Using Solid State Devices Is Called Photovoltaic  Generation Is Clean, Quite, and Reliable  Requires minimum operation & maintenance  Some cases it is the cheapest option of meeting the energy requirement   A solid state device which produces current when certain range radiation spectrum falls on it The operation consists of three steps Absorption of radiation ( pair production) Charge separation Collection ( flow of electron in the load circuit)  Various technology devices available are Crystalline Si, a – Si, thin film technologies like CdTe, CIGS, GaAs, DSSC and organic cells THEORITICAL EFFICIENCY ~BAND GAP ENERGY OF MATERIAL 1st generation Silicon wafer 2nd generation Thin film on glass 3rd generation Thin film on flexible foil 4th generation Organic cells Absorber thickness ≤ 200µm Absorber thickness ≤ 3µm Absorber thickness ≤ 3µm Absorber thickness ≤ 3µm Limited by wafer size Large area deposition Large area deposition Large area printing Rigid Rigid flexible flexible Mature Mature Emerging R & D stage Limited cost reduction potential Limited cost reduction potential Low cost potential lowest cost potential  Solar cell is the basic building block of any Solar PV system The current ~voltage characteristics are measured at Standard Test condition (STC) defined by three parameters Temperature ( 25 C), Irradiance (1000 W/M2 ), Spectrum (1.5G AM)  Open circuit voltage  Short circuit current  Maximum/peak power  Voltage at maximum power point  Current at maximum power point  Fill factor  Series resistance  Shunt resistance         Light Source: White Light Emitting Diode (W-LED) Light Out put: White colour (colour temperature 55000-65000K) minimum 15 LUX when measured at the periphery of meter diameter from a height of meter The illumination should be uniform without dark bands or abrupt variations, and soothing to the eye Higher light output will be preferred Mounting of light: Minimum metre pole mounted PV Module : 40 Wp under STC, measured at 16.4 V at load Module Voc minimum of 21V Battery: Tubular Lead acid Flooded or Tubular GEL / AGM VRLA , 12 V- 40 AH @ C/10, Max DoD 75% Electronics Efficiency: Min 85% total Duty cycle : Dusk to dawn Autonomy : days (Minimum 42 operating hours per permissible discharge     Rural sector (village lightening, water pumping, community light & TV, Telephone and health centre) Communication(very microwave repeater) low transmitter, Road & railways (signaling, panel interlocks, station lightning, track circuits) Others (battery charging, water purifier, warning light, cold storage, offshore platform lightening etc.) SOLAR LANTERN SOLAR HOME LIGHTING SYSTEM SOLAR STREET LIGHTING SYSTEM BILL BOARD LIGHTING SOLAR LANTERN SOLAR LIGHT IN A TRIBAL VILLAGE HOUSEHOLD SOLAR STREET LIGHT IN A VILLAGE IN BASTAR SOLAR POWERED TV IN A VILLAGE SOLAR SYSTEM FOR MICROWAVE REPEATER SYSTEM SOLAR SYSTEM FOR OFF SHORE PLATFORM SATELLITE EARTH STATION AT POOH  Participated in world solar challenge, december 2011 in Australia  Total distance 3000 kM  Top speed of 85 kM/ Hr  Powered by kW Multi crystalline PV Panel  48 V & 40 Ah, Li Fe PO4 batteries  MPPT charge controller  High power brush less DC hub Motor Solar powered Aero plane       All cost comparative statements between different sources of energy use the following formula for calculating energy cost Per kWh cost = (Total Construction Cost + Production Cost + Decommissioning Cost)/(MW rating X 1000 X Useful Life X Capacity Factor X 8760) Third party cost imposed by the industry never taken into account Considering the decreasing trend of PV cost Moore’s Law can be applied to it at 7% per year ( adjusted to inflation) If we calculate the cost of power from thermal PP, taking into account health hazard & other environmental & social issues, it is quite possible we have already passed the tipping point Paul Krugman has already advocated this The extern E-Pol project report also gives the external cost for thermal PP around 4-8 euro cents/KWh ? [...]... component configurations, and how the equipment is connected to other power sources  Stand alone systems  Grid interactive systems  Hybrid systems GRID CONNECTED SYSTEMS STAND ALONE PV SYSTEMS          PV ARRAY PANEL MOUNTING STRUCTURE COMBINER BOX CHARGE CONTROLLER BATTERY BANK INVERTER AC AND DC DISCONNECTS MISCELLANEOUS COMPONENTS( Cables, connectors, conduit and brackets) LOADS   ... assembly of PV modules and components to produce power for a particular service May be for electricity generation, pumping water or feeding power to lighting or any mechanical work Because of the modular characteristics, PV systems can be designed to meet the energy demand from few watt to megawatt Most favored for remote application where grid extension is not possible Can be designed for both AC and DC... the maximum power point voltage and delivers at load voltage Can be achieved by the following three methods 1 Perturb & measure: adjust voltage towards maximum power 2 Incremental conductance: finding value of V for dP/dV =0       It Is An Important Component For Stand Alone PV Systems Chemically stores electrical energy in the daytime & delivers power when required and renewable source is not available... challenges • Moving part and hence less reliable • Bankability • Higher area • Additional capital cost • Higher O&M Cost  A solar combiner box combines several solar panels into one dc output to be connected to the charge controller     A charge controller regulates the amount of current fed into a Battery bank from PV array Their main function is to prevent overcharging and deep discharge of the... but charge controllers also block battery bank current from leaking back into the PV array at night or on cloudy days, draining the battery bank It can be done with a normal ON/OFF switch which will connect/disconnect at the desired voltage of the battery to the PV array The two main types are PWM (pulse width modulated) and MPPT ( Tracking)   PWM is a way of digitally encoding analogue signal levels... matched Grid contacts should be uniform and optimized to have minimum contact resistance The lamination must not have any air bubble or pores for moisture ingression    A bypass diode is connected parallel to the cell string to prevent reverse biasing of the module at partial/complete shading of the PV module A blocking diode is connected in series to the PV module so as to prevent back flow of... conduit and brackets) LOADS      A number of modules assembled together with support structure is called an array Individual modules produce electric current and voltage that depends upon the specific module To have the desired voltage and current input we have to connect several modules in parallel/series For parallel connection modules must be voltage matched For series connection modules must... options are available (Lead-Acid, Ni-Cd, NiMH, Li- ion etc) Flooded lead –acid batteries are very common and cheap, hence widely used for this application During sun-less days, batteries are discharged but not charged These conditions result in battery operating in Partial State of Charge (PSOC) Cycling and Deep cycling Also, solar systems are installed in open atmosphere exposing the batteries to extreme... open atmosphere exposing the batteries to extreme Temperatures Other lead acid batteries fail in such conditions due to sulphation, stratification, corrosion and plate shedding Moreover, remote solar installations make water top-up difficult and costs money ... direction without undue stress Support structures to affix the array to either a roof, a pole, or the ground Must be unobstructed to get radiation & accessible for cleaning Basically two types - fixed and sun tracking type For fixed type panel mounting must be perpendicular to the noon day sun For tracking sun type provision is there for single or double axis rotational movement Material & mechanical ... configurations, and how the equipment is connected to other power sources  Stand alone systems  Grid interactive systems  Hybrid systems GRID CONNECTED SYSTEMS STAND ALONE PV SYSTEMS          PV. .. Ampere(3(3* *33A)A) 972 Watt (18 * 54 W) 972 Watt (18 * 54 W)      Integrated assembly of PV modules and components to produce power for a particular service May be for electricity generation,... characteristics, PV systems can be designed to meet the energy demand from few watt to megawatt Most favored for remote application where grid extension is not possible Can be designed for both AC and DC