Among the effective use of solar energy, solar photovoltaic lighting systems are the fastest growing and most dynamic research field in recent years. Solar energy is a kind of radiant energy. The solar photovoltaic lighting system is used to directly convert sunlight into electrical energy to provide lighting appliances. It can only be achieved with the help of energy conversion and storage.
Solar photovoltaic lighting systems are divided into two categories, namely independent solar photovoltaic lighting systems and grid-connected solar photovoltaic lighting systems. The difference between them is that the independent solar photovoltaic lighting system is equipped with battery energy storage, and the grid-connected solar photovoltaic lighting system directly sends the electricity generated by the solar cells into the grid.
The most obvious feature of an independent solar photovoltaic lighting system is the storage of battery energy. It is this feature of direct power supply from solar cells that gives the solar photovoltaic lighting system unparalleled advantages: no need for power grids, no need to lay wires, flexible, easy to carry, safe, energy-saving and environmentally friendly, etc. It has completely replaced traditional lighting devices in many occasions.
The application of solar photovoltaic lighting system is restricted by many conditions: the large one-time investment makes the cost much higher than traditional lighting systems. In addition, solar cell power generation needs to be able to receive the radiant energy of the sun. The shade of urban roads and the shadows of tall buildings all bring inconvenience to the application of solar photovoltaic lighting systems. The current solar LED lighting fixtures are mainly used in occasions such as urban secondary roads and rural roads, and cannot completely replace the city electricity lighting. But in the long run, with the decline in the price of solar cells and the research on energy-saving light sources, solar LED lighting will definitely play an increasingly important role. Solar LED lighting fixtures are mainly used in the following fields:
(1) Solar LED traffic lights. In China, solar cells were used in navigation lights as early as the early 1970s, and it has been more than 40 years now. Due to the advantages of solar photovoltaic lighting devices that do not need power grids, wires, and are flexible, no matter in navigation, aviation, or highway traffic lights, they have been widely used, and have achieved good economic and social benefits.
(2) Solar LED lawn lights. This is my country’s largest solar cell application project and the largest output of solar photovoltaic lighting devices in my country. Its output far exceeds the sum of other solar photovoltaic lighting devices. In 2006, nearly 200 million were exported.
(3) Solar LED flashlight. This is a solar photovoltaic lighting product that has just emerged in recent years. Its output is increasing every year and it has a wide range of applications.
(4) Solar LED craft light. Solar craft lights are basically made of resin, can be made into various forms, and are widely used in urban landscape lighting.
(5) Solar LED house light. Used to indicate house numbers at night.
(6) Solar LED road lighting fixtures. This is what people refer to as solar LED street lights. In recent years, it has attracted the attention of governments and media at all levels in the country. Many manufacturers and developers are very enthusiastic about investing in this project. Although solar LED road lighting fixtures account for a small proportion of the entire road lighting fixtures, people believe that it will become the mainstream of solar photovoltaic lighting devices, and even replace traditional road lighting fixtures in the future.
(7) Solar LED landscape lights. The appearance design of solar LED landscape lights is mostly formed by combining metal and engineering plastics. The lamp body can present a variety of shapes such as round, square, geometric patterns, etc., with various shapes and different styles, or luxurious and elegant, or simple and bright. The luminous colors are white, red, green, blue, purple, yellow, etc., gradually changing or flashing. When night falls, the control system automatically activates the lighting device. At a glance, the lamp body emits a uniform and soft light, and several colors jump and change, making the whole city’s night neon flashing, radiant, and exceptionally burnt. The lighting project using solar LED lamps can save a lot of money every year, which not only brightens the city, but also develops the city ecologically, and makes full use of energy. It is the most reasonable development direction in the world.
(8) Solar LED high pole light. The pole height of the solar high pole lamp is generally 8~13m, the lighting power is 50~130W, and the effective lighting area can reach hundreds of square meters.