Thiết kế hệ thống năng lượng mặt trời.

Total Rated Power Watts Load Duty Factor 0-1 Total Avg.. Power Watts Hour s of use Total Energy Consumption Watt- hours/Wh Total Rated Power Consumption = Rated Power x No.. Power =

Country Per capita consumption

(kwh/year)

India's power generation capacity will need to scale up -

Large

Hydro-Renewable Sources Nuclear

Source: CEA, Annual Report

 Most parts of India receive good solar

radiation 5-7 kWh/sq m/day

 Within 6 hours deserts receive more

energy from the sun than humankind

consumes within a year – Gerhard Knies

 I = 6 kwh/m2/day or 250w/m2

Efficiency = 15%

=> Power Produced = 37.5 W/m2

i.e 37.5 MW/KM2 i.e 1 GW/25 KM2

=>Thar desert area is 2.28 Lac KM2

(0.28 Million KM2)

So now you can imagine the potential!!!

 Mission aims to achieve grid tariff parity by 2022 through

 Cost reduction

 Research and development

 Local manufacturing and supporting infrastructure

Application Segment Target for Phase

I (2010-13)

Cumulative Target for Phase II (2013-17)

Cumulative Target for Phase III (2017-22)

Grid Solar Power

Off Grid Solar

 Solar capital of India with Asia’s largest solar park

 More than 600 MW solar photovoltaic installations

 Government launched special solar energy educational

 Programs to full fill increasing demand of technical experts

 Creating employment of 45,000 People in renewable energy sector

 Ambitious plan of generating 100,000 Million units of clean green energy annually

Best way to learn is looking at

 High Electric bills

 Increasing electricity tariff rates

 Frequent electricity cut off

 No contribution in environment saving

What if we used other sources of energy to power our house !!!

Lets see how we can work it out…

Which are…

 Free of cost (just requires initial investment)

 Provides more reliability

 Helps in contributing for saving environment

Advantages of solar energy –

 Locally available

 Free source of unlimited energy

If we want to power your house / this lecture hall by using solar power

Then,

1) How will we proceed ?

2) What will be the system size and cost?

3) What other systems we will have to integrate ?

4) What will be the methodology of sizing of each equipment ? 5) What precautions we will have to take and how much the overall system will cost?

1 Solar radiation assessment

2 Site survey and estimating maximum available energy

3 Understanding Photovoltaic technology

4 Requirement analysis

5 Determine load, power and energy consumption

6 System concept development

7 PV array and battery selections

8 Charge controller and inverter selection

Install and Run Pvsyst on your laptops

energy received from sun on a unit area perpendicular

to the rays of sun Radiation is inversely proportional to square of the distance

At the mean distance of sun and earth, rate at which energy is received from sun on unit area perpendicular to rays of sun is solar constant

Its value is 1367 W/m2 = Isc

Beam radiations (Direct ) Diffused radiations (Diffuse from sky + Reflected from ground)

Global (Beam+Diffused)

Measuring solar radiations

Amount of solar radiation on an object will depend on

 Location

 Day of year

 Time of day

 Inclination of the object

 Orientation of object (w.r.t North-south direction)

Here the Object is solar panel, but it is true of any object (For solar thermal also!)

*Only for easy visualization

Day of the year is characterized by an angle

Called as Declination angle (δ)

Angle made by line joining center of the sun and the earth w.r.t to projection on equatorial plane (+23.45o to -23.45o)

Study the effect of day /season through fixed tilt with our Simulation software PVsyst

Time of the day

Time is based on the rotation of the Earth with respect to the Sun

It is characterized by Hour angle (w) –

It is angular measure of time w.r.t solar noon (LAT),

Since 360o corresponds to 24 hours

15o corresponds to 1 hour

W = 15 (12 - LAT )

Local apparent time

In hour

Hour

angle

15 degree

per hour

With reference

to solar noon

In order to find the beam energy falling on a surface

having any orientation,

it is necessary to convert the value of the beam flux coming from the direction of the sun to an equivalent value corresponding to the normal direction to the surface

θ

beam flux

Equivalent flux falling normal

to surface



cos

n b

Ib

Ibn

- Orientation in horizontal plane (γ)

Solid lines are reference lines Vertical

β

γ

South direction (horizontal plane)

Angle of Sun rays on collector

sin cos

) sin cos

sin cos

cos (cos

cos

) sin cos

cos cos

cos (sin

sin cos

Surface slope (β) Declination angle (δ)

For the power output to be maximum, the incident

radiation must be perpendicular to the panel

Optimum inclination for fixed collector



  

The inclination of the fixed collector (facing South) w.r.t

horizontal at noon time should be

Under this condition at noon time Sun rays will be perpendicular to the collector

One need to estimate declination angle for a given day, when optimum inclination is to be estimated

 =0o, collector facing due south

) cos(

cos cos

) sin(

sin cos            

) cos(

Optimum Inclination over a Year

The noon position of the sun is changes throughout the year

What is optimum position of collector for whole year

(we need to estimate average value of declination angle over year)

-30 -20 -10 0 10 20 30

Azimuth orientation from PVsyst

Continuous tracking of sun will ensure that the sunrays are

always perpendicular to the solar panel (tilt angle=β is changed to ensure that incident angle=ϴ = 0)

Axis tracking from PVsyst

Now you know what should be the orientation of solar panels to get maximum output from fixed collector

problem is solved Actually Only 1/4th

Lets see what are other 3 parts …

We also need to look at

1 Energy requirement

2 What PV technology to choose ,

3 Actual installation and Financial part

Requirement Analysis

Customer concerns

Daily load requirements

Constraints- Cost and space constraints

Type of load

24x7power requirement for critical loads

Seasonal load requirement Future load requirement

Total Rated Power (Watts)

Load Duty Factor (0-1)

Total Avg

Power (Watts)

Hour

s of use

Total Energy Consumption (Watt-

hours/Wh)

Total Rated Power Consumption = Rated Power x No of Loads

Total Avg Power = Total Rated Power x Load Duty Factor

Total Energy Consumption = Total Avg Power x Hours of use

Prepare the load chart to analyze total energy consumption

Load entry in PVsyst

Why do we need batteries

 Storing energy produced by the PV array during the

day, and to supply it to electrical loads as needed

 To operate the PV array near its maximum power point

 To power electrical loads at stable voltages

 To supply surge currents to electrical loads and

Li-ion battery

Nickel Cadmium

hydride battery Lead acid battery

Dominant Energy Storage medium is Lead-Acid batteries

(Mostly used in off-grid systems)

Battery Sizing

1 Required Supply Wh = Load Wh * (No.of day of storage + 1)

2 Include Efficiency factors from name plate of battery

Depth of Discharge (DOD)

Battery efficiency factor (BEF)

System AC efficiency (ACEF)

{ACEF = Inverter Efficiency x AC Cable Loss Factor}

Select Battery Voltage (VBAT) based on system voltage

Small systems (<1kWh) are 12VDC

mid-range systems (1-3kWh) are 24VDC

larger systems (>3kWh) are > =48-120 VDC

Select nearest larger rating available

To be on the safe side

Battery pack

Check available Battery unit voltage and Ah

No of Battery units in parallel = Battery Pack Ah / Battery Unit Ah

No of Battery units in series = Battery Pack Voltage/Battery unit voltage

Remarks –

 Standard deep cycle lead acid battery voltage rating available is 12V

 Standard battery Ah available is 120Ah, 150Ah, 180Ah etc

 Example: 24V/350Ah Battery Pack

Battery specifications in PVsyst

Light energy  Electricity

It is generated due to principle of photoelectric effect

Let’s look at the process in some further detail:

• Photovoltaic energy is the direct conversion of light into electricity at the atomic level

• Some materials exhibit a

property known as the

photoelectric effect that causes

them to absorb photons of light

and release electrons

• When these free electrons are captured, an electric current

results that can be used as

electricity

Characteristics and Efficiency

in

m mP

I V

Intensity light

Incident

Power Cell

To estimate actual output

Temperature

V

gallium diselenide

or copper indium sulfide

• Organic

polymer-based photovoltaic

• Thermo

photovoltaic solar cells

0.00 0.20 0.40 0.60 0.80 1.00

PV Sizing

1 Load Wh = Daily energy requirements

2 Average daily peak sun hours (PSH) in design month for selected tilt and orientation of PV array

3 System Efficiency Factor (SYSEF)

SYSEF = Battery EF x PV EF x Cable EF x Charger EF x Inverter EF

4 PV Watts peak (Total Wp)= Load Wh/(PSH*SYSEF)

5 Select PV module voltage based on system voltage

(System voltage is integral multiple of PV module voltage)

6 Select module Wp and size based on available space

7 No of PV Modules = Total Wp/Module Wp

8 Use nearest larger number of modules

Off-grid System Loss Factors

Design of PV Array

1 Integral No of modules in string = system voltage/module nominal

voltage

2 No of strings in array = Total No of modules/No of modules in string

3 Use nearest larger number of strings in an array

4 List No of modules in array and Standard Testing Condition Wp rating of

array

PV MODULE Specifications in PVSYST

Something like a charge controller !!!

The additional advantage could be – Increased battery life

Preventing reverse current

A charge controller limits the rate at which

electric current is added to or drawn from

electric batteries

Types

PWM (Pulse Width Modulation)

- Helps to remove buildup on the plates in a battery extending a battery’s life

MPPT (Maximum Power Point Tracking)

- Adjusts the output voltage level to get maximum power output

Why solar charge controller is required !!!

Charge

controller

For battery

Increases battery life

Regulate power Preventing

reverse current Optimize power output

Charge Controller Selection

1 Match controller nominal system voltage to PV system voltage

2 Controller input voltage rating >= 1.2 x array open circuit voltage

3 Max charge current >= 1.25 x array max power point current

4 Nom load current = Max DC Load Power/System Voltage

5 Controller output current rating >= 1.5 x nom load current

Charge control specifications in PVsyst

Shadow analysis in PVsyst

latitude and usage pattern

Choosing PV technology and

mounting structure

Types of Mounting system

1 On-Roof Solar PV Panel Mounting Systems

2 Building integrated photovoltaic (BIPV)

3 On open ground Photovoltaic mounting structure

4 Tracking photovoltaic mounting structure

4 steps to design PV system for your home

1 Optimize tilt of solar panel

2 Estimate power and energy output of the plant based on

selected array and battery size and system efficiency factors

3 Review system design, sizing and costs

4 Implement design

Run simulation in PVsyst

Sizing and system specification

 Typical Size - 1W to tens of kW

 Battery back up is essential for operation in monsoon and at night

 Long life and low maintenance

 Upgradability is often required

 Loads are combination of DC and AC

 Module cost is 30-40% of system cost, battery cost is recurring and

appliances cost is often included in system cost

 System cost is in the range of Rs 1.25-1.5 Lakhs/kW

Off-Grid Systems: Scope, Applications and Costs

Solar PV system

Sine wave inverter

Square wave

Mechanism continually changes current direction

Induced to Sine wave

1 Stand alone inverter

 Used in isolated systems where the inverter draws its DC energy from batteries charged by photovoltaic arrays

 Unlike grid tie inverters, stand-alone inverters use batteries for storage

 These types of inverters are mostly used in residential buildings in remote locations which are devoid of the utility grid and is powered by renewable energy sources

2 Grid tied inverter

 That converts direct current (DC) electricity into alternating current(AC)

and feeds it into an existing electrical grid

 During a period of overproduction from the generating source, power is

routed into the power grid, thereby being sold to the local power

company

 During insufficient power production, it allows for power to be purchased

from the power company

 The grid tie inverter must synchronize its frequency with that of the grid

(e.g 50 or 60 Hz) using a local oscillator and limit the voltage to no higher

than the grid voltage

SOLAR POWER CONDITIONING UNIT (PCU) is used

as control system for grid tie inverter

Inverter Selection

 Match inverter DC input voltage to system voltage

 Match inverter AC output voltage to nom load voltage

 Inverter output power rating 1.5 to 2 times (min 1.2 times) max load

power to allow for future expansion

 Inverter nom load current = Max load power/Nom output voltage

To conceptualize

the system

Designing electric system for efficient power utilization

Development

of Energy storage system

Implementation

of energy efficient system What is there for you in the box…

Opportunities Manufacturing

Installation & Maintenance

Product Design Design & Engineering

• Semiconductor technology

• Building integrated Photovoltaic

Research and Development

• Customized project development

• Project consultancy

Project Development & Consultancy

• System integration in solar PV

• Low skill in module assembly

Manufacturing

• Third-party installers are not skilled

• Grid integration of mega watt scale PV power projects

Construction and Installation

• Trouble shooting of circuitry of appliances

• Mechanical Maintenance

Operation and Maintenance

• After sales-service, customer care

• Techno-commercial analysis

Marketing

Sector Estimated

Current employment

Estimated projected Employment

2017 2022

Solar PV On-Grid 4,000 39,000 1,52,000

Solar PV Off-Grid 72,000 1,40,000 2,25,000

Total 76,000 1,79,000 3,77,000

With the Jawaharlal Nehru National Solar Mission (JNNSM) scheme

of the Government of India, the installed capacity is estimated to reach 20 GW by the year 2022 This would create enormous employment opportunities in the country

Infinite Free Energy

Decentralized Power

Solar lantern Solar fly pad Solar PV shading

Solar powered satellite Overhead PV system Solar car