How Can You Maximize Solar Panel Output | Tilt Angle, Cleaning, Shading

Tilt angle set as local latitude ±10° can elevate power generation about 5%–10%; monthly cleaning can reduce dust loss 3%–7%; avoid shading (shadow <5%) and use shading analysis tool to optimize layout can gain 5% above.

Tilt Angle

Find tilt angle
When sunlight with 90 degrees included angle vertically irradiates on panel surface, photoelectric conversion efficiency locates at the highest peak value, surface reflectivity will follow it drop to 2% below. The Earth's surface different regions' sunshine trajectory drop is extremely big. Assume a building house located at north latitude 35 degrees' position, put the whole piece panel completely paved flat on a 0 degrees' horizontal surface, every year's total power generation degree number will be compared to locating at the optimal tilt angle time be less 21.5%.

Fixed installation has a kind of most universal mathematical formula, is putting tilt angle numerical value set as with local geographical latitude exactly the same. Fixed at this angle, the whole set system's whole year received solar radiation photon amount can reach the theoretical maximum value of 87% to 92%. Aiming at different latitude intervals' equipment, specific fine-tuning parameters are as follows:

· The house is located at latitude 0 degrees to 15 degrees' low latitude interval inside, suggesting taking tools to put tilt angle fixed at 15 degrees, absolutely do not equal to the local's extremely low latitude number, leaving a bit slope can guarantee rain snow has enough gravity acceleration flowing down, passingly wash away accumulated dust.

· Located at latitude 15 degrees to 25 degrees between's building, tilt angle numerical value set as with actual latitude absolutely consistent, output's whole year electric quantity waveform graph is the most smooth.

· Locating at latitude 25 degrees to 40 degrees interval's roof, put bracket angle on locating latitude numerical value's basis on again add 5 degrees, can perfectly make up autumn winter seasons sunshine total time length becoming short brought's 6% yield attenuation.

· At latitudes exceeding 40 degrees, high latitude region, put panel tilt angle set as local latitude plus 10 to 15 degrees, can in sun elevation angle extremely low's whole 3 months winter inside, put light interception rate forcedly elevate 18%.

Change season follows adjusting
the Sun's rising height at the summer solstice and winter solstice's two poles states between, has a huge vertical drop of as high as 47 degrees. Willing every year to climb onto the roof to operate two times' people, can use extremely low's labor cost exchange back a sum extra's electric power return. Every time you go, you only need to take a piece of 14-millimeter open-end wrench, consume about 30 to 45 minutes to loosen the bracket nut, move the telescopic pole to its hole position, then screw tight is okay.

· Summer's 90 days inside, put tilt angle press low, adjust to locating latitude subtract 15 degrees' position, noon time period's sunlight direct incidence rate can approach 99%, let June to August's single month power generation bill out of thin air jump increase 12% to 14%.

· Arrived in winter, the light ray in the sky's oblique incidence angle becomes extremely big. At this time, put the tilt angle toward up lift, lift high to latitude add 15 degrees' steep position, not only can let winter total power generation amount pull high 15%, attached's a physical revenue is multiplied speeded up snow sliding down's speed. Surface tilt angle reaches 45 degrees, thickness being 10 centimeters' snow only needs 3 hours' weak sunlight heating then can whole piece slide down; locating at 30 degrees tilt angle's same model panel, big probability will be by that piece snow dead dead covered as long as 100 hours, period inside whole piece panel's power output infinitely approaches 0 watts.

· At vernal equinox and autumnal equinox, around each 90-day time period, put angle adjust back to equal to local latitude, exactly matches medium height's sun parabola trajectory, maintains single day average 5.5 hours full load operation's peak value.

Do not pave too gentle
Water flow toward down sliding's speed and gravity angle present strict's positive correlation. Once the installation tilt angle is lower than 10 degrees, the rain water drop fall to the glass surface's flow speed will be lower than 0.5 meters/second, that kind of soft soft's water flow basically does not take away air inside settled down's gravel particles. Every time experiencing precipitation lower than 5 millimeters/hour's small rain, drizzle will put full screen's dry dust gather into big lump's muddy water drops, subsequently following temperature rise moisture evaporation, at panel bottom end aluminum alloy frame above 1 to 3 centimeters' region, solidify into a strip thickness reaching 2 to 4 millimeters' mud band.

As long as this strip mud band shaded a piece standard 144 half-cell photovoltaic module bottom most only 5% of the light transmitting area, the whole string cell board's internal working voltage will then suddenly drop from standard's 40 volts to 26 volts, the whole piece panel's instantaneous output power on the spot plummet 30% above. In order to maintain panel surface light transmittance of 95% or above throughout the year, even if equipment is installed near the equator, the lowest tilt angle also absolutely does not be lower than 15 degrees.

15 degrees tilt angle at encountering precipitation intensity reaching 15 millimeters/hour's medium shower time, glass surface's mud sand washing peeling rate can reach 88% above, making that kind relying on manual taking long handle water brush climbing onto roof to go cleaning's frequency, from every year's 6 times largely cut down to 2 times, every year per kilowatt installed capacity can save about 120 liters' municipal tap water.

Prevent blowing big wind
Windward side's tilt angle open the bigger, panel back side encountering strong wind time produced's aerodynamic drag then will multiply double. Take a piece standard size being 2.2 meters long, 1.1 meters wide, weighing 28 kilograms, around a monocrystalline silicon panel to test, when its installation tilt angle is set at 15 degrees, at wind speed reaching 30 meters/second's environment under, chassis bearing's upward lifting physical load is about 0.4 kilonewtons (kN). If it is put at a tilt of 40 degrees to cater to the high latitude's winter sunshine, the same one wind speed under's wind force load will instantly surge to 1.3 kilonewtons.

· To resist doubled 3 times' wind pressure, aluminum alloy bracket's profile thickness must be forcibly upgraded from the standard's 2.0 millimeters to 3.0 millimeters above, every piece panel corresponding's thickened hardware accessories cost will rise about 4.5 monetary units.

· If the flat roof cement roof surface adopts counterweight block ballast installation scheme, 40 degrees tilt angle's panel every piece needs to press on a total weight not lower than 60 kilograms' cement brick blocks; 15 degrees tilt angle's panel only needs to press on 25 kilograms' cement brick blocks, then it can be steady like Mount Tai.

· Facing a slope being 22 degrees' conventional asphalt shingle pitched roof, sticking to the roof's slope flat paving installation, can be compared to additionally going purchasing adjustable angle bracket legs save down per watt 0.15 monetary units' material fee. Following slope flat paving lost away's that 3% to 4%'s whole year power generation amount, converted into electricity fee amount, about will consume 12.5 years' long time only then will exceed initially purchasing angle adjusting bracket what extra spent's budget.

Add a tracker
Budget extremely sufficient's ground large-scale power station, or possessing a spacious backyard's single-detached house, launching a set by mechanical motor-driven's single-axis solar tracking bracket, can eat up every thread angle brought's bonus. Single-axis tracker internal installed has photosensitive sensor and thick's transmission shaft, can drive rows' panel modules at every day early morning 6 o'clock pointing to east direction negative 60 degrees, following time pushing forward, at evening 6 o'clock turn to west direction positive 60 degrees, a whole day all can put panel and sunlight ray's incidence included angle error dead dead control at 5 degrees within.

· In cloudless weather, the amount of direct radiation is extremely high in large pieces of the dry zone, single-axis tracking bracket can let the whole set of equipment's annual total power generation amount compared to fixed tilt angle system high out 25% to 30%.

· From a hardware ledger look, a single-axis system will make per watt's initial installation cost increase 0.12 to 0.18 monetary units. Driving that unit tracking motor turn on a whole day, what consumes electric quantity, merely occupies whole system that day's total power generation amount's 0.4% to 0.6%.

· More complex dual-axis trackers not only track every day's east-west direction, but also synchronously adjust the south-north direction's up-down pitch angle. The whole set's huge mechanical structure can again squeeze 8% of the electric quantity output, but its construction cost is as high as fixed bracket's 2.5 times. Dual-axis system every interval 2500 running hours then must manual take oil gun for all rotating bearings inject lubricating grease, 10 years life cycle inside's transmission motor failure rate statistical data reached 4.2%.

Cleaning

Dust blocked light
Continuous 45 days precipitation lower than 20 millimeters' dry weather, will let air inside suspended's PM10 micro particles at photovoltaic panel's tempered glass surface deposit out a thickness being about 1.5 millimeters' dust layer. That layer 1.5 millimeters' dry shading object, will put penetrating glass reaching below silicon wafer's solar photons block away 6.5% to 8.3%. Assembling rated power being 400 watts' single piece module, at standard illumination radiation intensity 1000 watts/square meter's environment under, its actual output power will immediately drop to 368 watts around.

If the panel tilt angle is 15 degrees below, the bottom edge aluminum alloy frame place accumulated's mud band can reach 3 millimeters thick, covering most bottom a row area being about 156 millimeters multiplied by 156 millimeters' cells. That piece being covered's cell will from the power generation unit become a consuming electricity resistor, bearing as high as 12 volts' internal reverse bias voltage, at short short 45 minutes' continuous sun exposure after, its local temperature will soar to 85℃ above.

· Bird poultry kind feces belongs to strong acidic excrement, its acidity alkalinity pH value normally falls in the 3.5 to 4.5 interval. If letting alone a small piece of diameter 4 centimeters' bird droppings attached on the panel surface exceeding 30 days, an acidic substance will permanently corrode away the glass surface layer, which only has a 2 micrometer thick anti-reflection coating (AR coating).

· Being corroded away coating's region, light ray reflectivity will from original's 2.5% rise to 7.8%, causing single piece panel peak power (Wp) permanent loss to reach 1.2%.

· Residing in close to agricultural farming areas or sandy soil exposed zones, the building's panel single month accumulated's falling ash weight can reach 4.5 grams, the whole string system's actual grid-connected electric quantity will with every day 0.15% rate present linear downward slide.

Pick a good time: noon 12 o'clock to afternoon 2 o'clock, solar radiation intensity locates at 1,000W/m²'s highest peak, panel surface's physical temperature will climb to 65℃ to 75℃. Take water pipe inside extracted temperature only being 20℃'s municipal tap water toward glass on spray, as high as 55℃'s instant temperature gradient difference, will let 3.2 millimeters thick's photovoltaic smooth surface tempered glass produce intense's thermal expansion cold contraction physical reaction. Silicon-based material's thermal expansion coefficient is 9×10^-6/℃, intense temperature difference will induce naked eye cannot see's cell hidden crack, crack will spread with per second 0.1 millimeters' speed inside the internal silicon wafer network.

· Holding water pipe climbing roof's action must be arranged at early morning 7 o'clock before or evening 6 o'clock after, must use a temperature measuring gun to confirm panel surface temperature has already dropped to 35℃ below then pass water.

· Precipitation abundant's temperate climate region, sets standard cleaning cycle is every interval 90 days to 120 days conduct 1 time; physically locating sandstorms frequently happening or as long as 6 months no rainfall's arid desert zone, must put frequency compress to every 30 days execute 1 time.

· At pollen concentration reaching per cubic meter 500 grains, spring's big outbreak period, pollen particles carry extremely strong viscous grease, merely relying on wind speed reaching 8 meters/second's natural wind basically unable to blow it falling, needs to put spring's washing schedule advance 15 days.

Tools do not randomly select
Municipal pipe network transmitted's tap water if its total dissolved solids (TDS) numerical value exceeds 200 ppm, water flow at high temperature glass on evaporate after, will intactly leave down thickness being about 0.05 millimeters' calcium carbonate and magnesium carbonate white scale crystals. Scale crystals' light transmittance is extremely poor, accumulated 3 times washing after, will cause extra 2.3% electric quantity loss. Adopting multi-stage reverse osmosis (RO) water purification equipment filtered out pure water, put TDS numerical value forcedly press low to 15 ppm within, moisture evaporates after glass surface's residue weight is almost 0 milligrams.

Connecting high pressure cleaning machine operation time, water pump output's physical pressure absolutely not allowed to exceed 40 bar (bar), also is about 600 pounds/square inch (psi). Water gun nozzle's hole diameter needs to be greater than 2 millimeters, spraying water column must present a 45-degree fan shape spread open, and gun head distance glass surface's straight line distance must not be less than 30 centimeters.

Selected's cleaning bristles must be polymer nylon material, single root bristle's diameter needs to be smaller than 0.2 millimeters, length keeps at 50 millimeters to 70 millimeters between, bristle top end must pass through blooming branching treatment, prevent extremely sharp's polymer edge scratch flower that layer 2 micrometers thick's anti-reflection coating.

Aiming at adhering extremely firm's industrial oil stains or bird droppings, only can mix in acidity alkalinity pH value locating at 6.5 to 7.5 between's neutral phosphorus-free detergent, single time cleaning per kilowatt (kW) installed capacity's modules, standard's water consumption data should be controlled in 15 liters to 25 liters' range inside.

Cleaning operation method	Water consumption/kilowatt (liters)	Early stage hardware equipment budget (monetary unit)	Average power generation amount recovery rate (%)	Suggested applicable's execution frequency
Natural rainfall washing	0	0	45 - 60	Depending on local meteorological precipitation probability, decide
Manual pure water soft brush	18 - 25	80 - 150	97 - 99	Every 90 days to 120 days, 1 time
Full automatic guide rail robot	2 - 5	2500 - 4500	95 - 98	Every day early morning automatically run 1 time
Mobile high pressure water gun	35 - 50	300 - 600	92 - 95	Every 180 days to 360 days, 1 time

Calculate this sum account
Rated installed capacity being 10 kilowatts' residential roof equipment, at experiencing 6 months' falling ash period after, overall power generation efficiency will from nominal's 98% slide down to 83%. 15%'s efficiency attenuation, projected to the whole half year's time axis, equivalent to out of thin air lost 1500 degrees electricity (kWh)'s usable electric energy. According to the per degree electricity 0.25 monetary units' feed-in tariff, book on's economic loss reached 375 monetary units.

Hiring a professional team conducting door-to-door operation, single piece 2.2 square meters specification's module charging standard is about 3 monetary units. A 10-kilowatt system normally consists of 25 pieces of panels assembled and formed, and single time outsourced labor fee needs to pay out 75 monetary units. Put the whole year's maintenance plan as 2 times, total expenditure 150 monetary units, exchanged back then was 375 monetary units' full amount electric power output, pure profit recorded 225 monetary units.

Self go to the hardware store and procure a piece of carrying water pipeline's 6 meters long carbon fiber telescopic pole, plus a handle nylon soft bristle brush and a matched resin water filter, total spending only 80 monetary units. Pay out 2 hours' climbing and physical labor, consume about 500 liters of household pure water, whole set of tools input in system running's front 4 months inside then can thoroughly return capital. Cleaning completed power on test after, inverter display screen on's direct current input ampere (A) numerical value, will immediately from trough period's 18.5 amperes rebound to full load state under's 21.8 amperes, single day power generation total degree number steadily pull rise back to full state's 98.5%.

Shading

Tree shade costs electricity
Single piece rated power being 400 watts' photovoltaic panel internal normally by 108 pieces or 144 pieces monocrystalline silicon half cells connected in series spliced and formed, when roof beside's a root antenna projected down's shadow shaded panel merely 5%'s physical area, namely about 0.1 square kilometers' surface layer region, whole string cell board's working current will instantly from full load's 11.5 amperes sharply drop to 3.2 amperes. Based on series circuit, the current must keep consistent's physical attribute, that piece suffered 5% area shielded's cell will act as a piece as high as 15 ohms' resistor, making the whole piece panel's real-time output power plummet 30% to 50%.

If a set system assembled a unit input voltage threshold of 200 volts' string inverter, connecting 12 pieces panels, among which even if only has 1 piece panel encountering 10% of the area covering, the whole string direct current circuit's voltage data will then drop to 180 volts, the inverter's photoelectric conversion efficiency will from nominal's 98.5% sudden drop to 82.4%.

In order to deal with this kind of voltage difference, the panel's internal installed 3 pieces bypass diodes at bearing 0.6 volts' reverse voltage time will be forced to open, every diode in the open state will consume 2.4 watts' electric energy. Every day, from 9 a.m. to 3 p.m., the high radiation time period inside, as long as 6 hours' local coverage will lead to whole day total 1.8 degrees electricity (kWh)'s energy in vain flow loss.

Series photovoltaic string's short board effect in physics presents out a kind 1 to 99's magnification rate, merely shielding area reaching 1.5 square millimeters' a piece dried bird dropping plaque, then can let the whole string containing 432 pieces of silicon-based units' array output power in 0.2 seconds inside sudden drop 42.5%, making single day total power generation amount revenue record 6.8 percentage points' attenuation.

Calculate shadow length
At latitude 42 degrees, the geographical region, winter solstice day, that day's noon sun elevation angle will drop to extremely low's 24.5 degrees, a root distance solar array true south direction 5 meters away, height being 6 meters' exhaust chimney, at 10 o'clock in the morning, can project out a strip as long as 13.1 meters' oblique direction shadow. Following the earth's rotation, this strip width reaching 0.8 meters' shadow will with per minute 0.25 meters' speed at panel surface transverse move, from morning 10 o'clock to afternoon 1 o'clock, this 3 hours inside, continuously cover array bottom most's 3 rows totaling 36 pieces of cell units. Suffered this kind of moving shadow's influence, the whole array at this 3-hour cycle inside received's effective solar radiation amount will reduce 650 watts/square meter, causing winter single-month power generation total amount's loss rate as high as 18.2%.

In order to eliminate height drop brought by optical interference, installation manual on calibrated obstacle and equipment between's horizontal leave empty distance calculation formula is obstacle height multiply 2.3 times' coefficient, that root 6 meters high's chimney surrounding must reserve 13.8 meters' no shading radius. If the roof itself carries a 18-degree tilt slope, shadow projection's geometric proportion still needs to be multiplied by a 1.15 times' magnification parameter, making the safe clearance distance's numerical value be pulled long to 15.8 meters.

Building physical spacing sets fault tolerance rate at low sunshine elevation angle environment under's standard range is extremely small, when obstacle height exceeds 2.5 meters, every one meter's vertical height variable all will produce 2.85 meters' horizontal shadow projection length, forcing low array surface received's short wave radiation amount as high as 850 watts per square meter.

Scald broken semiconductor
A piece size being 4 centimeters wide, 6 centimeters long's autumn fallen leaf if tightly adhered to a glass panel for as long as 48 hours, being completely covered's that piece silicon cell internal's electron transition movement will thoroughly stop, it will from a power generation unit transform into a bearing 9.5 amperes strong current passing through's energy consuming load. 9.5 amperes' current forcibly squeezes past this high impedance region, will produce as high as 45 watts' local thermal load, at sunshine radiation intensity reaching 1000 watts/square meter's noon time, merely needs 22 minutes' heating time. This point's glass surface temperature will then soar from 35℃'s normal working value to 105℃.

Panel internal that layer used to stick cell's EVA encapsulation film its physical melting point set at 90℃, breaking through melting point after, EVA film will with per week 1.8% speed produce permanent yellowing degradation, making light transmittance from 99% slide down to 85%. This kind of accompanying 105℃ high temperature's local hot spot, will with every cycle 0.15 millimeters' extension rate induce internal micro cracks, when temperature gradient produced's mechanical stress exceeds 45 megapascals (MPa), whole piece 3.2 millimeters thick's tempered glass at following's 6 months inside will happen self-explosion shattering's statistical probability will climb to 12.5%.

Hot spot effect triggered's semiconductor crystal lattice breaking possesses irreversibility, when a single unit silicon wafer's local heat breaks through 110 degrees Celsius' physical threshold, its surface layer 2 micrometers thick's silicon nitride anti-reflection coating will happen chemical peeling, making this specific region's photon absorption rate permanently lower 14.2%, equipment 25 years' warranty period in advance 13 years terminate.

Add-on optimizer
Dealing with every day producing as high as 15% area shading's complex roof environment, put originally that set 600 volts high voltage series topology structure dismantled, for every piece 400 watts' panel back side solely add install a unit micro inverter, can let every piece panel own independent's MPPT (maximum power point tracking) algorithm channel. micro inverter's internal processing chip owns 99.8% tracking precision, its startup voltage's parameter standard is only 22 volts, far lower than traditional models' 200-volt threshold, making early morning startup power generation time advanced 45 minutes.

When the array inside an A panel is covered by a tree canopy, 35% of the area, its independent output power will accurately drop to 260 watts, while separated 1 meter locating at complete sunshine under a B panel still can full load output 385 watts' electric energy. Procuring this kind of micro hardware will let single piece panel's input increase 130 monetary units, whole set system per watt installed capacity's capital expenditure (CapEx) data will float up 0.18 monetary units.

At the period being 12 months' running cycle inside, this set's independent bottom layer architecture can put originally flowed lost's whole year power generation amount back 24.5%, making equipment's annual average system availability maintain at 99.9% standard line on, in 20 years' life cycle inside, per degree electricity's levelized cost of energy (LCOE) numerical value from 0.08 monetary units compress to 0.065 monetary units.