grid-tied system sizing
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Grid-Tied System Sizing. Module 11 Fall 2009. Sizing a Grid-Tied PV System. Design Beginning Points Annual Electric Usage Available Space For System Panels and Electrical Budget Constraints. Sizing Process:. Sizing begins at the load side and proceeds backwards to the array - PowerPoint PPT PresentationTRANSCRIPT
Grid-Tied System Sizing
Module 11Fall 2009
Sizing a Grid-Tied PV System
• Design Beginning Points– Annual Electric Usage– Available Space For System Panels and
Electrical– Budget Constraints
Sizing Process:
• Sizing begins at the load side and proceeds backwards to the array
• Grid-Tied systems are usually sized as large as possible within limits of budget and space
• Sizing of Stand-Alone systems involves a fine balance between energy supply and demand. Not covered in this class.
Accepted Method for Certification in CoSEIA
• Electric Load Estimation – 1. Approximate monthly and daily average energy
use• Yearly Average energy consumption: 7000 kWh/yr• Avg. kWh/yr ÷12mo = 583 kWh/mo• Avg. kWh/mo ÷ 30 days = 19.5 kWh/day
• This is Average Daily Load
Accepted Method for Certification in CoSEIA
• Electric Load Estimation – 1. Approximate monthly and daily average energy
use• Yearly Average energy consumption: 7000 kWh/yr• Avg. kWh/yr ÷12mo = 583 kWh/mo• Avg. kWh/mo ÷ 30 days = 19.5 kWh/day
• This is Average Daily Load
Step 1a
• 50% of power to be generated by PV
• 19.5 (AC)kWh/day x 50% of power from PV
= 9.75 (AC) PV system kWh/day
2. Array Sizing
• Average Sun Hours per day…. Denver (5.5 – 6 hours)
– See Irradiation chart– Or data in back of book
Solar Radiation Chart
3. Determine PV system kW needed
9.75 (AC) PV system kWh/day ÷ 5.5 (ASH/day) = 1.77 (AC) PV System Kilowatts
4. Factor in inverter efficiency
• 1.77 (AC) PV System Kilowatts ÷ .80 derate factor = 2.21(DC) PV array System kW needed
• 2.2 kW PV array x 1000 Watts/kilowatt = 2200 PV array watts
From the Book…
• Establish design kWh/day
• Divide by average peak sun hours
• Factor in Inverter efficiency
• Choose Modules
• Inverter Sizing
Inverter Sizing
• Calculate total watts of array
• Choose inverters that will pass that quantity of watts
• Check string sizing software to evaluate overall compliance with design criteria
• Decide how many strings your system will utilize
End of Day 2 presentation