Solar energy for solar energy system is a kind of inexhaustible, endless, pollution-free green energy given by nature, but it has the characteristics of randomness and intermittently.
It is estimated that the earth gets about 7×1017 kWh of energy from the sun in a year, while the land gets about 1.3×1016 kWh of solar energy in a year.
Due to the different latitude and longitude of different regions on the earth, the average daily exposure and sunshine time of different regions in China vary greatly. The average daily exposure in China ranges from 2.6kwh/m2D to 6.4kwh/m2D, and the annual sunshine number ranges from 1,000 to 3,300 h.
Solar energy system is composed of solar cell module, solar controller and solar batter.
Solar energy is a kind of clean and renewable new energy, which has a wide range of functions in people's life and work. One of them is to convert solar energy into electric energy. Solar power generation is divided into photothermal power generation and photovoltaic power generation.
Solar power generation usually refers to solar photovoltaic power generation, which has the characteristics of no moving parts, no noise, no pollution, high reliability, and solar energy system has excellent application prospects in the communication and power supply system in remote areas.
(1) Solar cell module of solar energy system: The solar cell module is the core part of the solar power supply system and the most valuable part of the solar power supply system.
Its function is to convert the solar radiation energy into electrical energy, or sent to storage batteries, or to promote the load work.
The quality and cost of solar modules will directly determine the quality and cost of the whole system.
(2) Solar controller of solar energy system: The role of the solar controller is to control the working state of the entire system, and the battery has played a charge protection, over discharge protection.
In the place with large temperature difference, the qualified controller should also have the function of temperature compensation.
Additional functions such as light switches and time switches should be optional for the controller.
(3)Solar battery of solar energy system: generally lead-acid battery, small and micro system, can also be used nickel hydrogen battery, nickel cadmium battery or lithium battery.
The idea is to store the electricity generated by the solar modules when there is light, and release it when needed.
Features of solar energy system for power supply
1) Long life: The quality guarantee period of crystal silicon solar cell modules is 15-20 years;
2) High performance: The crystal silicon solar cell power generation system is resistant to typhoon, hail, moisture and ultraviolet irradiation, etc. The module system can work normally under the environment of minus 40 degrees to 70 degrees above zero;
3) No duty: it can supply power to the load just like conventional energy without personnel duty during operation;
4) Uninterrupted power supply: solar energy system design takes into account the local rainy weather, and stores the excess energy in the battery to ensure that the user still has enough energy for use in rainy days;
5) DC non-interference power supply: solar cell power generation equipment, no noise, no high-order harmonic interference in power supply, especially suitable for communication power supply;
6) Not affected by geographical environment: Plain, river, ocean, high mountain, snow field, island, forest area, any place that needs electricity can use crystal silicon solar cell power generation system.
(1) Determine the power and daily power consumption of monitoring equipment
The outfield surveillance camera adopts high-speed gun camera with an input voltage of 220VAC and a maximum power consumption of 100W.
The input voltage of the photoelectric converter is 24VAC, and the maximum power consumption is 10W.
132. In line with the operation requirements of the monitoring system to the camera, it is determined that the average total power consumption of the whole camera system is 80W, and the total daily power consumption is 80W, which I 24h= 1920WH = 1.92kwh (degree).
(2) Solar energy and battery pack configuration scheme
1) Main index requirements: The solar cell module is guaranteed to have a long service life, with a design of more than 10 years;
Battery capacity can meet the equipment load 72h(3D) continuous cloudy and rainy day power supply.
2) Determine parameters according to solar energy system operation
The Angle of solar cell square array is 38;
The radiation amount obtained by the square array of solar cells is 1.1 times of the face value.
The average daily peak sunshine hours (square plane) in Nanning area is 3.54h.
Set the minimum interval between two consecutive rainy days as 15d.
3) Battery capacity design of solar energy system
The capacity of the battery is important to ensure a continuous supply of power.
Since the electricity required by the equipment is provided by the battery, the generated electricity of the solar array should be stored in the battery for equipment consumption every day. However, the solar array needs to send a part of the extra electricity to be stored in the battery for rainy days.
Therefore, the capacity Bc of solar battery is calculated as follows:
Bc=A, QL, NL, T0 / Cc Ah
1.2/0.7 = 1. 4 3 ╳ ╳ ╳ 160 Ah
= 1152 Ah
Material 1200 Ah
A is the safety factor, between 1.1 and 1.4;
QL is the average daily power consumption of load, is the working current multiplied by the number of working hours per day;
NL is the longest continuous rainy days;
T.is the temperature correction coefficient, generally 1 above 0 ° C, 1.1 above −10 ° C, 1.2 below −10 ° C;
Cc is the discharge depth of the battery, and the general lead-acid battery is set at 0.70.
Therefore, solar battery is selected as 12V/1200AH, and the unit is selected as 12V/200AH, with 2 strings and 3 unions, forming 24V /600AH, totaling 6 pieces.
4) Square array design of solar cells
The basic unit of solar cell square array is to select a single group of 12V,75 Wp solar panels.
The number of solar panels needed
Daily output of a single solar panel:
If I power, charging time, comprehensive charging efficiency, loss
= 75Wp I 4.44h I 0.7 I 0.9 = 209.79WH ≈ 210Wh
Daily power consumption: daily power consumption of load/inverter efficiency = 1.92kwh / 0.9 = 2.133kwh
Number of solar panels required:
Daily power consumption/daily generating capacity of a single solar panel =2133Wh/210Wh=10.15≈10 blocks
Power of solar cell module
A total of 10 75Wp solar panels are required, 2 in series of 5 and calculated as 24V/ 750W.
5) Inverter power supply
Because the input voltage of the integrated gun camera is 220VAC, and the input voltage of the optical terminal machine is 24VAC, it needs to be equipped with an inverter to convert 24V DC into 220VAC and then supply power to the load.
6) Intelligent solar controller of solar energy system
Industrial grade chip, over charge, over discharge, overload protection, short circuit reverse connection;
Microcomputer time controller, AC/DC output.
7) Heat preservation and moisture prevention measures are adopted, i.e. colloidal batteries, etc.
In the solar power supply system, the solar cell directly supplies power to the load in sunny days when there is sunshine, and at the same time supplements the discharge from the battery to the load power supply station when there is no sunshine. No sunshine, cloudy and rainy days by the battery discharge for communication equipment electricity.
Solar energy system is different from the power supply system composed of mains power supply, high frequency switching power supply and battery.
The latter battery group is in the floating charging state of constant voltage most of the time, and the high frequency switching power supply has higher automation function and perfect battery management function.
When solar battery is discharged, the rectifier performs current limiting charging on the battery, and the battery can be recharged regularly according to the need.
With the change of local ambient temperature, the general rectifier can also make the floating charging pressure of the battery automatic compensation, so that the battery can always work in a fully charged state, which is conducive to prolong the service life of the battery.
Solar energy systems, on the other hand, cannot control the amount of electricity produced by solar cells, rather than generating electricity on demand.
When solar battery is in the state of full capacity or basic full capacity, in order to ensure that the battery bank does not charge and the output voltage of the system does not exceed the allowable voltage range, part of the solar cells will be removed from the system.
After the deep discharge of the battery, the solar battery will not generate more electricity because the battery needs to be charged.
Therefore, the operating mode of the battery in this system is neither floating charge mode nor complete charge and discharge mode.
Solar battery charging is neither constant voltage charging nor constant current charging.
The charging current of the battery changes with the change of sunshine intensity and the input and cut of solar battery square array, and the voltage also changes accordingly.
In order to ensure the service life of solar battery of solar energy system, the long-term charging voltage of single battery should be controlled below 2.40V.
Note for operation and maintenance of solar energy system from solar energy products manufacturer
(1) When the continuous cloudy and rainy weather, battery discharge is large, no matter whether the battery reached the discharge termination voltage, should be promptly used to replace the battery with a mobile power generation device.
Prevent in the battery capacity has not reached the basic state of full rain weather, resulting in the interruption of power supply and because the battery is not charged timely after discharge affects the service life of the battery.
(2) Because the operating mode of the battery is not a complete floating charge operation mode, the service life of the battery is shorter than that of the battery in the conventional power supply system.
Should grasp the capacity of the battery, especially in the use of a few years, should be in the continuous rainy weather season every year before the battery capacity test, if the capacity cannot meet the requirements, to take timely measures.
(3) Part of the connecting cables between solar cell square array and solar power supply combination power supply are located outdoors, and the cables should be checked regularly for aging and good connection.
(4) In order to give full play to the effectiveness of solar cells, the inclination Angle of solar cell square array plane can be adjusted according to seasonal changes in a year.
(5) The surface of solar cell phalanx should be kept clean, otherwise it will affect the generating capacity of solar cell phalanx.
(6) The appropriate temperature of the battery room is 5℃~30℃ and humidity ≤85%RH.
In the bureau (station) with solar power supply system, attention should be paid to warmth and ventilation when designing the machine room.
Room environment temperature is also not allowed to ignore the factor, can take appropriate measures, such as the use of solar cell inverter, the direct current inverter for 220V ac, to solve the room air-conditioning power.