Design Solar PV System

 

Design Solar PV System 1. Determine power consumption demands    The frst step in designing a solar PV system is to fnd out the total power and energy consumption o all loads that need to be supplied by the solar PV system as ollows:  

1.1 Calculate total Watt-hours per day for each appliance used.   Add the Watt-hours needed or all appliances together to get the total W Watt-hours att-hours per day which must be delivered to the appliances.   1.2 Calculate total Watt-hours per day needed from the PV modules.   ultiply the total appliances Watt-hours per day times !." #the energy lost in the system$ to get the total Watt-hours per day which must be provided by the panels.

2. Size the PV modules  %i&erent si'e o PV modules will produce di&erent amount o power.. To power To fnd ou outt the si'ing o PV module( the total t otal pea) watt produced needs. The pea) watt #Wp$ produced depends on si'e o  the PV module and climate o site location. We have to consider *panel generation actor+ which is di&erent in each location. ,or Thailand( the panel pan el generation actor is ".". T To o site determine the si'ing o PV modules( calculate as ollows:

2.1 Calculate the total Watt-pea rating needed for PV modules   %ivide the total Watt-hours per day needed rom the PV modules #rom item !.$ by "." to get the total Watt-pea) rating needed or the PV panels needed to operate the appliances.  

2.2 Calculate the num!er of PV panels for the system

 Watt-pea) %ivide the PV answer obtained in item .! by the rated o the modules available to you. /ncrease anyoutput

 

ractional part o result to the ne0t highest ull number and that will be the number o PV modules re1uired. 2esult o the calculation is the minimum number o PV panels. / more PV modules are installed( the system will perorm better and battery lie will be improved. / ewer PV modules are used( the system may not wor) at all during cloudy periods and battery lie will be shortened.

". #n$erter sizing  An inverter is used in the system where A3 power output is needed. The input rating o the inverter should never be lower than the total watt o appliances. The inverter must have the same nominal voltage as your battery battery.. ,or stand-alone systems( the inverter must be large enough to handle the total o Watts you will be using at Watts one time.  The inverter si'eamount should be 4-"56 bigger than total W atts o appliances. /n case o appliance type is motor or compressor then inverter si'e should be minimum " times the capacity o those appliances and must be added to the inverter capacity to handle surge current during starting. ,or grid tie systems or grid connected systems( the input rating o the inverter should be same as PV array rating to allow or sae and e7cient operation.

%. &attery sizing   The battery type recommended or using in solar PV system is deep cycle battery. battery. %eep cycle battery is specifcally designed or to be discharged to low energy level and rapid recharged or cycle charged and discharged day ater day or years. The battery should be large enough to store su7cient energy to operate the appliances at night and cloudy days. To To fnd out the si'e o battery( calculate as ollows:   .! 3alculate total Watt-hours per day used by appliances.   . %ivide the total Watt-hours per day used by 5.84 or battery loss.   ." %ivide the answer obtained in item . by 5.9 or depth o

 

discharge.   . %ivide the answer obtained in item ." by the nominal battery voltage.   .4 ultiply the answer obtained in item . with days o autonomy #the number o days that you need the system to operate when there is no power produced by PV panels$ to get the re1uired Ampere-hour capacity o deep-cycle battery battery..

Battery Batt ery Capacity Capacity ( Ah )

¿

Total Watt −hou hours rs per day used used by applianc appliances es x Days Days of auton autonomy omy (0.85 x 0.6 x nominal battery voltage)

'. Solar charge controller sizing   TheVoltage solar charge controller is the typicall typically y charge rated against Amperage and Voltage capacities. elect solar controller to match the voltage o PV array and batteries and then identiy which type o solar charge controller is right or your application. a)e sure that solar charge controller has enough capacity to handle the current rom PV array.the array.the si'ing o controller depends on the total PV input current which is delivered to the controller and also depends on PV panel confguration #series or parallel confguration$.According to standard practice( the si'ing o solar charge controller is to ta)e the short circuit current #/sc$ o the PV array( and multiply it by !." olar charge controller rating ; Total short circuit current o PV array 0 !."

 

1. Determine power consumption demands   Totalapplianceuse = P t = 261 Wh / day Total PV panels panels energ energyy needed needed =261× 1.3=340 Wh / day

2- Size the PV panel Total ℘ of PV panel panel capacit capacityy needed needed =340 / 3.4 =100 W P  Number of PV panelsneeded panels needed =100 / 100=1

So this system should be powered by at least 1 modules of 100 Wp PV module.

". #n$erter sizing   The inverter inverter ¿ 300

%. &attery sizing Nominal battery voltage =12v  Days of autonomy=1 Battery Batt ery capacit capacityy =

  (261∗1) =43 ( 0.85∗0.6∗12 )

 

Total Ampere-hours required 43 Ah !o the battery should be rated 12 " #$ Ah for 1 day autonomy%

'. Solar charge controller sizing  olar charge charge controller controller ratin=Total short short cir circuit cuit current current of PV arra arrayy x 1.3