JEE4980 Sr Design Project. Residential Concept

Transcription

1 JEE4980 Sr Design Project Photovoltaic System (PV) Module through Main Service Panel Project Implementation Discussion Wilcox Chapter 2 Lab Time continued project design work Refer to your electronic handout /3 PV Systems folder for Sandia and SEI design tools Photovoltaic Systems 1 Residential Concept PV Modules PV Array Battery Protection Inverter Disconnects Main Service Panel Photovoltaic Systems 2 1

2 Photovoltaic Systems 3 Photovoltaic Systems 4 2

3 Photovoltaic Systems 5 Cells to Array Connect cells to make a module Connect modules to make an Array STP Module Ratings Photovoltaic Systems 6 3

4 Bypass Diode Photovoltaic Systems 7 Residential Use vs Solar Generation Photovoltaic Systems 8 4

5 Battery Sizing Flowchart Photovoltaic Systems 9 Lead Acid Battery Photovoltaic Systems 10 5

6 Battery discharge supply load External circuit Electrons enter the Anode and leave the Cathode Anode Cathode Photovoltaic Systems 11 Discharge Both electrodes converted to lead sulfate Lead sulfate build up reduces surfaces area and performance Avoid full discharge Size system considering depth of discharge Lead Antimony can cycle down to 20% of charge Simple battery model circuit is an ideal dependent DC source in series with a resistor 2.12v / cell (no load) when fully charged Voltage diminishes as it discharges Temperature and rate of discharge affect performance Typically 95% efficient Photovoltaic Systems 12 6

7 Charge Battery from PV Source External circuit Electrons enter the Cathode and leave the Anode Anode Cathode Photovoltaic Systems 13 Charge Some H atoms converted to H2 gas Cathode is converted back to Pb Overcharging increases H2 gas Need higher voltage to charge Typically 95% efficient Cell voltage drops to 1.95 V at full discharge (depends on chemical formulation) Photovoltaic Systems 14 7

8 Charge & Discharge V for Lead Acid Battery Capacity C in Ah gives coulombs of charge stored Energy = (V terminal )(Ah) / 5 (10, 20) hour charge or discharge Internal losses I 2 R so less efficient at 5 h Higher temperature stores more energy Photovoltaic Systems 15 Battery Considerations Must respect Depth of Discharge (DoD) Vented (flooded) vs Non-vented (sealed) Maintenance Short term: Water, connections Long term: End of life, replacement cost Lifetime - # of cycles affected by DoD Temperature Enclosures, space Other battery types: NiCad, NiZn, NiMH Photovoltaic Systems 16 8

9 Protection DC AC Inverter Photovoltaic Systems 17 Small PV Interconnection Photovoltaic Systems 18 9

10 Wiring Example & Method From Photovoltaics Design & Installation Manual by Solar Energy International See 6 handout sheets from Photovoltaics Design & Installation Manual in folder Photovoltaic Systems 19 Wiring Example Photovoltaic Systems 20 10

11 Wiring Solution Photovoltaic Systems 21 AC & DC Schematic Photovoltaic Systems 22 11

12 Grounding and Bonding Photovoltaic Systems 23 From Battery Management Systems by Pop, Bergveld et al Photovoltaic Systems 24 12

13 Lithium Ion Battery Photovoltaic Systems 25 Lithium Ion Battery Discharge Capacity vs Cycle # Photovoltaic Systems 26 13

14 Lithium Ion Battery State of Charge is a function of Voltage, Impedance, and Relaxation Time Most of these depend on Temperature too. Relaxation Time is how long it takes the battery to relax to its internal EMF when current is interrupted. Photovoltaic Systems 27 Lithium Ion Battery Photovoltaic Systems 28 14

15 Lithium Ion Battery Photovoltaic Systems 29 Appendix Slides after this for reference only Photovoltaic Systems 30 15

16 Power Flow Controller Photovoltaic Systems 31 Power Compensators Photovoltaic Systems 32 16