20 PV Calculation Formulas

n=Pm (peak power of the cell)/A (cell area) x Pin (incident light power per unit area)

Where: Pin=1KW/㎡=100mW/cm²

Vmax=Vrated x 1.43 times

3.1 Number of battery modules in parallel = average daily power consumption of the load (Ah)/average daily power generation of the module (Ah).

3.2 Number of battery modules in series = system operating voltage (V) x coefficient 1.43/peak operating voltage of the module (V).

Battery capacity = average daily power consumption of the load (Ah) x number of consecutive rainy days/maximum discharge depth.

Average discharge rate (h) = number of consecutive rainy days x load working time/maximum discharge depth.

Load working time (h) = ∑ load power x load working time/load power

7.1 Battery capacity = average power consumption of the load (Ah) x Number of consecutive rainy days x discharge correction factor/maximum discharge depth x low temperature correction factor

7.2 Number of batteries in series = system operating voltage/battery nominal voltage

7.3 Number of batteries in parallel = total battery capacity/battery nominal capacity

8.1 Component power = (electrical power x electricity time / local peak sunshine hours) x loss coefficient Loss coefficient: take 16~2.0 according to local pollution level, line length, installation angle, etc.

8.2 Battery capacity = (electrical power x electricity time / system voltage) x continuous rainy days x system safety factor System safety factor: take 1.6~20, according to battery discharge "depth, winter temperature, inverter conversion efficiency, etc.

Component (square array) = K x (electrical working voltage x electrical working current x electricity time) 1 When the local annual radiation total is maintained by someone + general use, K is taken as 230: when no maintenance + reliable use, K is taken as 251; when no maintenance + harsh environment + very reliable requirements, K is taken as 276

10.1 Array power = coefficient 5618 x Safety factor x total load power consumption/slope correction factor x average annual radiation on the horizontal plane

Factor 5618: Based on the charge and discharge efficiency coefficient, component attenuation coefficient, etc.: Safety factor: Based on the use environment, whether there is a backup power supply, whether there is someone on duty, etc., take 11~1.3.

10.2 Battery capacity = 10 x total load power consumption/system operating voltage; 10 is the no sunshine coefficient (applicable to continuous rainy days not exceeding 5 days).

11.1 Current

Component current = load daily power consumption (Wh) / system DC voltage (V) x peak sunshine hours (h) x system efficiency coefficient

System efficiency coefficient: including battery charging efficiency 0.9, inverter conversion efficiency 0.85, component power minus + line loss "+ dust, etc. 0.9, adjusted according to actual conditions.

11.2 Power

Component total power = component power generation current x system DC voltage x coefficient 1.43.

Coefficient 1.43: Ratio of component peak operating voltage to system operating voltage

11.3 Battery Pack Capacity

Battery pack capacity = [load daily power consumption Wh / system DC voltage V] x [number of consecutive rainy days / inverter efficiency x Battery discharge depth]

Inverter efficiency: about 80%~93% according to equipment selection: Battery discharge depth: according to its performance parameters and reliability requirements, choose between 50%~75%.

12.1 Calculation Of System Battery Pack Capacity

Battery pack capacity (Ah) = safety times x average daily load power consumption (Ah) x maximum continuous rainy days x low temperature correction factor/battery maximum discharge depth factor.

Safety factor: between 11-1.4: Low temperature correction factor: 10 for above 0"C, 11 for above -10℃, 12 for above -20℃: Battery maximum discharge depth factor is 0.5 for shallow cycle, 0.75 for deep cycle, and 0.85 for alkaline nickel-cadmium battery.

12.2 Number Of Modules Connected

Number of modules in series = system operating voltage (V) x coefficient 1.43 / selected module peak operating voltage (V)

12.3 Calculation Of Average Daily Power Generation Of Modules

Daily average power generation of modules = (Ah) = selected module peak operating current (A) x peak sunshine hours (h) x slope correction coefficient x module attenuation loss coefficient

Peak sunshine hours and slope correction coefficient are actual data of the system installation site: Module attenuation loss correction coefficient mainly refers to the loss due to module combination, module power attenuation, module dust covering, charging efficiency, etc., generally 0.8.

12.4 Calculation Of The Battery Capacity Required To Be Replenished For The Shortest Interval Between Two Consecutive Rainy Days

Replenished battery capacity (Ah) = safety factor x average daily power consumption of load (Ah) x maximum number of consecutive rainy days.

Calculation of the number of parallel modules:

Number of parallel modules = [replenished battery capacity + average daily power consumption of load x shortest interval days] / average daily power generation of modules x shortest interval days

Daily average power consumption of load = load power / load working voltage x number of working hours per day.

Annual power generation = (kWh) = local annual total radiation energy (KWH/㎡) x photovoltaic array area (㎡) x module conversion efficiency x correction factor. P=H·A·n·K

Correction coefficient K=K1·K2·K3·K4·K5

K1 is the reduction coefficient of the long-term operation of the component, taking 0.8: K2 is the correction for the power reduction caused by dust blocking the component and the temperature rise, taking 0.82; K3 is the line correction, taking 0.95; K4 is the inverter efficiency, taking 0.85 or according to the manufacturer's data: K5 is the correction coefficient for the orientation and tilt angle of the photovoltaic array, taking about 0.9,

Photovoltaic array area = annual power consumption/local annual total radiation energy x component conversion efficiency x correction coefficient A=P/H·n·K

1 cal = 41868 joules (J) = 116278 milliwatt-hours (mWh)

1 kilowatt-hour (kWh) = 3.6 megajoules (MJ)

1 kilowatt-hour/㎡ (KWh/㎡7) = 36 megajoules/㎡ (MJ/㎡) = 0.36 kilojoules/cm (KJ/cm) 100 milliwatt-hours/cm (mWh/cm) = 85.98 cal/cm (cal/cm)

1 megajoule/meter (MJ/m) = 23 889 cal/cm (cal/cm) = 27.8 mWh/cm (mWh/cm) When the radiation unit is cal/cm: Annual peak sunshine hours = radiation x 00116 (conversion factor) When the radiation unit is megajoule/meter: Annual peak sunshine hours = radiation - 36 (conversion factor) When the radiation unit is kilowatt-hour/meter: Peak sunshine hours = radiation - 365 days When the radiation unit is kilojoule/cm, peak sunshine hours = radiation 0.36 (conversion factor)

Battery capacity 25h x inverter power / rated voltage of battery pack

Power generation cost price = total cost + total power generation

Power station profit = (power purchase price - power generation cost price) x working time within the power station life Power generation cost price = (total cost - total subsidy) - total power generation Power station profit = (power purchase price - power generation cost price 2) x working time within the power station life Power station profit = (power purchase price - power generation cost price 2) x working time within the power station life + non-market factor income

Without subsidy: annual power generation x electricity price - total investment cost x 100% = annual return rateWith power station subsidy: annual power generation x electricity price - (total investment cost - total subsidy) x 100% = annual return rateWith electricity price subsidy and power station subsidy: annual power generation x (electricity price + subsidized electricity price) + (total investment cost - total subsidy) x 100% = annual return rate

19.1 inclination angle

latitude Horizontal tilt angle of the module

0"-25° tilt angle = latitude

26°-40° tilt angle = latitude + 5°-10° (+7° in most parts of my country)

41°-55° tilt angle = latitude + 10°-15°

Latitude>55" tilt angle = latitude + 15°-20

19.2 Azimuth

Azimuth angle = [peak load time of the day (24h system) - 12] x15 + (longitude - 116)

D=0707H/tan[acrsin(0 648cosФ-0 399sinФ)]

D: front and rear spacing of the module array

Ф: latitude of the photovoltaic system (positive in the northern hemisphere, negative in the southern hemisphere)

H: vertical height from the bottom edge of the rear photovoltaic module to the top of the front shield