1. P14421: Smart PV Panel Bobby Jones: Team Leader Sean Kitko
Alicia Oswald
Danielle Howe
Chris Torbitt

2. AGENDA Project Overview Heat Analysis Electrical Design System Layout
Test Plans
BOM
MSD II Schedule

3. Project Overview

4. Project Overview Advance Power Systems
Jasper Ball
Atlanta, GA
Snow reduces power output of PV panels
Develop method to prevent snow from accumulating in the first place
Apply current to conductive, heating ink
Keep temperature of panel surface above freezing
Sense presence of snow

5. Heat Analysis

6. Heat Analysis Process
1 How much power is produced by the panel if there was no snow
Uses TMY3 data which is the most average months weather in Rochester
Calculates solar beam angles on panel based on time of day and day of year and angle of panel tilt
Calculate how much energy panel produces from TMY3 data, solar beam angle, efficiency of panel (19%) and area of panel (0.024m)

7. Heat Analysis Process con’t
2 Find energy required to heat the panel in between ink traces to 5°C
Length and spacing determined by cell size.
Limited to where bus bars on cells were
Coefficient of convection (h) ranges from 5 to 28
Modeled sections of cell using fin analysis
Was able to calculate m, to get temperature at ink and qfin

8. Cell

9. Heat Analysis Process con’t
3 Calculate total energy
qfin values already calculated
Calculate qmelt based on an average snowfalls rate over 4 hours
Uses ice properties (h=33400J/kg)
Assumes density of snow=60 kg/m2
Calculated qrad
Uses glass properties and surrounding temperature
Total qgen is the sum of these in each section

10. Heat Analysis Process con’t
4 Compare different ink configurations based on qgen calculation
qgen was calculated based on sections of a cell
Calculations for configs based on an entire panel, not just one cell
Conclusion: Configuration 2 is the more efficient in all cases

11. Configuration 1
16 Sections
Sections
sections

12. Configuration 2
8 Sections
Sections

13. Configuration 3
4 Sections
Sections

14. Configuration 4 10 Sections 4-0.031 Sections 4-0.052 Sections

15. Heat Analysis Process con’t
5 calculated specific convection coefficient for each hour of the day it snows
Uses TMY3 data
Does not take into account the direction of wind or the angle of panel
Temperatures all rounded to nearest degree
Conclusions: All Reynolds's numbers were <5*105 therefore all used laminar model

16. Heat Analysis Process con’t
6 calculated energy required for snow prevention on panel
Uses h that was calculated
Uses same process as qgen calculation but uses data for that specific day
Snow data could not be found on hour basis, so assumed snows for four hours when most energy could be generated

17. Heat Analysis Process con’t
7 find how much light gets to the panel when snow is left to accumulate
Uses equation found on next slide
Equation used when there is snow accumulation.
As time moves forward, the snow accumulates
Snow is assumed to be left on panel for the rest of the day
Each day it is assumed there is not snow starting on the panel

18. Percentage of Light vs. Snow Depth

19. Heat Analysis Process con’t
8 Graphically compare results
Took the amount of energy required to melt snow over four hours (when there was snow) and subtracted that from how much energy the panel would produce with no snow
Took the calculated amount of light that would get through the snow and graphed that

20. January 2

21. February 10

22. March 5

24. Energy Conclusion:
Total energy for one year if snow is prevented: *107J (-20,823Wh)
Total energy for one year if panel was left alone: about 3,300,000J (916.5Wh)
Snow prevention is not the best way to get rid of snow from an energy standpoint
Suggest seeing energy consumption if snow is allowed to accumulate then heated up to slide off. Only found through testing.

25. ANSYS – Heat Transfer

26. Electrical Design

27. Sensors

28. Sensors

29. Sensors

30. Sensors

31. Sensors

32. Simulations

33. Simulations

34. Simulations

35. Power Electronics

36. Power Usage Don’t want the battery to go below 40% Capacity
Power Management
Item
Current (A)
Voltage (V)
Time (Hrs)
Power (W)
Amp Hrs
Ink 10 8 4 82 40
MicroController
0.0002
3.3 24
0.0048
Charge Controller
0.01 12
0.12
0.24
OPIC Light Sensor
0.0005
0.012
LM35 Temp sensor 5
0.0012
Thermocoupler amplifier
0.001
Totals
Needed Battery Capacity
Efficiency in Cold
Choose battery
60%
Don’t want the battery to go below 40% Capacity
Takes into account Efficiency in Cold Temperatures

37. Power Electronics Schem

38. Solid State Relay

39. Regulators
BP5275 Series
MAX1681

40. Battery and Controller
Trojan 31-AGM Battery
Getting a free AGM battery from a contact at Renewable Rochester
Morningstar SS-20L 20 Amp PWM Solar Charge Controllers w/LVD ($78)

41. POC CONTROL SYSTEM •32K of program space
Atmel's ATMega328P 8-Bit Processor in 28 pin DIP package with in system programmable flash
Features:
•32K of program space
•23 programmable I/O lines 6 of which are channels for the 10-bit ADC.
•Runs up to 20MHz with external crystal.
•Package can be programmed in circuit.
•1.8V to 5V operating voltage
•External and Internal Interrupt Sources
•Temperature Range: -40C to 85C
•Power Consumption at 1MHz, 1.8V, 25C
–Active Mode: 0.2mA
–Power-down Mode: 0.1μA
–Power-save Mode: 0.75μA (Including 32kHz RTC)

42. POC CONTROL SYSTEM Con’t

43. POC CONTROL SYSTEM Con’t

44. POC CONTROL SYSTEM Con’t

45. POC SENSOR RESEARCH

46. Enclosure

47. Enclosure and Layout

48. BILL OF MATERIALS

49. Risk Assessment and Mitigations

50. TEST PLAN OUTLINE Heat Transfer Test
Explores how heat propagates through glass from electrified trace
Apply a DC voltage to ink trace
Use thermocouples to measure temperature of glass at various locations
Multiple applied voltages, multiple ink trace resistances
Steady state and transient

51. TEST PLAN OUTLINE
Heat Transfer Test Diagram

52. TEST PLAN OUTLINE Switch Simulation Test
Explores functionality of heater system with simulated sensor inputs
Using switches, apply various combinations of sensor inputs
Verify that microcontroller wakes up when appropriate (interrupt test)
With simulated inputs, verify that microcontroller can make decisions to melt.

53. TEST PLAN OUTLINE Integrated System Test
Explores full functionality of system in expected environment
Install system in a realistic environment
Verify sensor functionality
Verify microcontroller interrupts when appropriate
Verify microcontroller accurately reads values
Verify heater functionality
Either with simulated or actual sensor inputs, verify that the system can melt snow efficiently.

54. MSD II SCHEDULE P14421 MSD II – Tentative Schedule Weeks 1-3:
Weeks 1-3:
MSD I issues summarized. Mitigation strategies implemented (Jan 28th)
Comprehensive and detailed Test Plan completed (Jan 28th)
Test and Prototype components and systems
Create preliminary C-Code for systems controller
Begin construction and customization of enclosure
Weeks 4 and on:
Detailed/Finalized Testing
Iterative testing and refinement of system and subsystems
Technical paper and poster
Confirm deliverables have been met