p14421: smart pv panel
DESCRIPTION
P14421: Smart PV Panel. Bobby Jones: Team Leader Sean Kitko Alicia Oswald Danielle Howe Chris Torbitt. AGENDA. Project Overview Heat Analysis Electrical Design System Layout Test Plans BOM MSD II Schedule. Project Overview. Project Overview. Advance Power Systems Jasper Ball - PowerPoint PPT PresentationTRANSCRIPT
P14421: Smart PV PanelBobby Jones: Team LeaderSean KitkoAlicia OswaldDanielle HoweChris Torbitt
AGENDA
•Project Overview•Heat Analysis•Electrical Design•System Layout•Test Plans•BOM•MSD II Schedule
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
Project Overview
Heat Analysis
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)
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
Cell
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
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
Configuration 116 Sections8-0.013 Sections8-0.052 sections
Configuration 28 Sections8-0.039 Sections
Configuration 34 Sections4 0.078 Sections
Configuration 410 Sections4-0.031 Sections4-0.052 Sections2-0.029 Sections
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
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
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
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.50
5
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100f(x) = − 10.5295788625791 ln(x) + 27.2693484173735
Series1Logarithmic (Series1)
Snow Depth (cm)
Perc
enta
ge
Percentage of Light vs. Snow Depth
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
January 2
0:00 4:48 9:36 14:24 19:12 0:00 4:48
-140000
-120000
-100000
-80000
-60000
-40000
-20000
0
20000
Energy Total Prevention (J)Energy Total Accumulation (J)
February 10
0:00 4:48 9:36 14:24 19:12 0:00 4:48
-200000
-150000
-100000
-50000
0
50000
Energy Total Prevention (J)Energy Total Accumulation (J)
March 5
0:00 4:48 9:36 14:24 19:12 0:00 4:48
-100000
-80000
-60000
-40000
-20000
0
20000
40000
Energy Total Prevention (J)Energy Total Accumulation (J)
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February
Energy Total Prevention (J)Energy Total Accumulation (J)
Energy Conclusion:•Total energy for one year if snow is
prevented: -7.5*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.
Heat Analysis: ANSYS Modeling
ANSYS ModelingGoals:
• Utilize ANSYS modeling to verify Alicia’s analysis• Compare various ink layouts for efficiency of heat spread
Process:• Made models in ANSYS representing various ink pattern layouts• Modeled numerous scenarios• Based on 5”x 5” cells that will be used in prototype
Assumptions:• Convection on back of panel can be neglected due to
insulation/lack of exposure• Thermal conductivity of glass = 1.4 W/m2
• Thermal conductivity of ink = 300 W/m2
Variables::• Ink temperature (Ranges from 20-45°C)• Bulk temperature (Ranges from -10 to 0°C)• Convection coefficient (Ranges from 8 to 22 W/m2-K)
Ink Layout 1• Represents squares
of ink in corners between cells.
• Approximately 1 cm2 of ink at each location
• Poor heat spread, inefficient.
• Majority of cell at -5°C, overall regardless of ink temperature.
Layout 1: h=12W/m2, Tink=45°C, Tbulk=-5°C
Layout 1: h=12W/m2, Tink=30°C, Tbulk=-5°C
Ink Layout 2• Represents a
zigzag pattern of ink around all edges of cells.
• Heat doesn’t spread to center.
• Center of cell at -2°C with ink at 45°C
• Not efficient.
Layout 2: h=12W/m2, Tink=45°C, Tbulk=-5°C
Layout 2: h=12W/m2, Tink=25°C, Tbulk=-5°C
Ink Layout 3• Represents having 2
mm thick lines of ink between cells.
• Isn’t effective for allowing heat to spread across entirety of cell.
• Majority of cell still at -4°C
Layout 3: h=12W/m2, Tink=25°C, Tbulk=-5°C
Ink Layout 4• 2 mm lines of ink
between cells, 1.5mm line down center of cells.
• Most conducive to successful heat spread.
• Increasing convection along with lower bulk temperatures can lead to issues.
Layout 1: h=12W/m2, Tink=45°C, Tbulk=-5°C
Layout 4: h=14W/m2, Tink=25°C, Tbulk=-10°C
Layout 3 vs. Layout 4
• Comparing having a center line of ink across cells vs. not
– Apparent that the extra line allows for much better heat spread.
• Verifies that 3 line pattern is best option.
Layout 4: h=12W/m2, Tink=25°C, Tbulk=-5°C
Layout 4: h=12W/m2, Tink=25°C, Tbulk=-5°C
Effects of Adjusting Variables
• Heat spread most affected by increased convection rather than decreasing ambient temperature.
Layout 4: h=12W/m2, Tink=25°C, Tbulk=-10°C
Layout 4: h=18W/m2, Tink=45°C, Tbulk=-10°C
Electrical Design
Sensors
Simulations
Power Electronics
Power Usage
Don’t want the battery to go below 40% Capacity
Takes into account Efficiency in Cold Temperatures
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 0.00066 0.0048
Charge Controller 0.01 12 24 0.12 0.24
OPIC Light Sensor 0.0005 3.3 24 0.00165 0.012
LM35 Temp sensor 0.00005 5 24 0.00025 0.0012
Thermocoupler amplifier 0.0002 5 24 0.001 0.0048
Totals 82.12356 40.2628
Needed Battery Capacity Efficiency in Cold Choose battery
64.42048 60% 103.072768
Power Electronics Schem
Solid State Relay
Regulators•BP5275 Series
• MAX1681
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)
POC CONTROL SYSTEM
• 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, 25C
–Active Mode: 0.2mA–Power-down Mode: 0.1μA–Power-save Mode: 0.75μA (Including 32kHz RTC)
POC CONTROL SYSTEM Con’t
POC CONTROL SYSTEM Con’t
POC CONTROL SYSTEM Con’t
POC SENSOR RESEARCH
Enclosure
Enclosure and Layout
BILL OF MATERIALS
Risk Assessment and Mitigations
TEST PLAN OUTLINE
MSD II SCHEDULEP14421 MSD II – Tentative Schedule 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