1. Photovoltaic Systems Engineering Session 22
SEC598F18
Photovoltaic Systems Engineering
Session 22
Residential PV System Case Study
Design, Financing, Permitting
November 21, 2018

2. Session 22 - Value to class members
A case study to compare and contrast the “textbook” and actual design, operation, and analysis of a residential grid-tied PV system
Design process
Permitting and construction
Operation
Life Cycle Costing
Payback Analysis

3. Grid-Tied PV Systems – The Design Process
Design Steps in a Residential Scale System
Examination of site and estimation of performance
Securing financing
Carrying out PV system engineering and design
Securing relevant permits
Construction
Inspection
Connection to the grid
Performance monitoring

4. Grid-Tied PV Systems – The Design Process
Design Goals in any Residential Scale System
Meeting expected (or modeled) performance
Engineering professionalism
Reliable performance
Standards and Codes
Safe operation
Architectural aesthetics
Building and Zoning

5. Grid-Tied PV Systems – The Design Process
Step 1 - Examination of site and estimation of performance
Inspection of roof and yards
Evaluation of obstacles, shading, and structures
Examining the solar resource

6. Step 1 - Examination of site and estimation of performance
Inspection of roof and yards

7. Step 1 - Examination of site and estimation of performance
Inspection of roof and yards

8. Step 1 - Examination of site and estimation of performance
South vs West

9. Step 1 - Examination of site and estimation of performance
ASU Parking Structure

10. Step 1 - Examination of site and estimation of performance
PV array sizing and
module selection
14 modules:
7 x 2 array

11. Step 3 - Carrying out PV system engineering and design
“Power Pergola”

12. Grid-Tied PV Systems – The Design Process
Step 2 – Agreement with Builder/Installer
Cash Purchase
Contract with Sky Renewable Energy, Phoenix
Homeowner will build the raised platform for the solar modules
Sky will purchase the modules, inverters, BOS, and install theses components on the pergola
Sky will produce and deliver to APS and the City of Phoenix the required electrical drawings

13. Grid-Tied PV Systems – The Design Process
Step 3 - Carrying out PV system engineering and design
Evaluation of space availability, solar availability, and electrical consumption
PV array sizing
Module selection
Inverter selection
Balance of system

14. Step 3 - Carrying out PV system engineering and design
Evaluation of electrical consumption
Average monthly baseline usage – 160kWh

15. Step 3 - Carrying out PV system engineering and design
Comparison of electrical consumption to solar electricity production
Annual total electrical usage – 5300 kWH
Annual total solar electricity production – 6300 kWh
PVWatts W system, 18o tilt
Ratio: 6300/5300 = 1.19; By APS regulations, the ratio cannot exceed 1.25

16. Step 3 - Carrying out PV system engineering and design
Inverter Selection
Option 1: A 4kW string inverter
Option 2: Microinverters installed directly on the backs of the PV modules

17. Grid-Tied PV Systems – The Design Process
Step 4 – Securing relevant permits
Special overlay districts
Architectural considerations
Zoning ordinances
Setbacks, elevations, materials
Building permits
Construction practices; electrical enclosures, wiring, components
Engineering approvals
Mechanical considerations
Utility agreements
Connection arrangements; net metering rules; electrical signal quality

18. Step 4 – Securing relevant permits - HPO

19. Grid-Tied PV Systems – The Design Process
Step 4 – Securing relevant permits
Special overlay districts
Architectural considerations
Zoning ordinances
Setbacks, elevations, materials
Building permits
Construction practices; electrical enclosures, wiring, components
Engineering approvals
Mechanical considerations
Utility agreements
Connection arrangements; net metering rules; electrical signal quality

20. Step 4 – Securing relevant permits – P&Z

21. Grid-Tied PV Systems – The Design Process
Step 4 – Securing relevant permits
Special overlay districts
Architectural considerations
Zoning ordinances
Setbacks, elevations, materials
Building permits
Construction practices; electrical enclosures, wiring, components
Engineering approvals
Mechanical considerations
Utility agreements
Connection arrangements; net metering rules; electrical signal quality

22. Step 4 – Securing relevant permits – P&Z