Solar landscape lighting constraints in the application of factors and solutions
 Editor's note: people in cities need to build the building of a city's character, and create a city character, display technology and the city of urban culture. In Tianjin, north China this important international port cities, landscape lighting as Hongtuo, strengthening the urban landscape, has gradually become a culture, a sustainable development of the human landscape.

 From 1992 onwards, Tianjin, the landscape lighting from scratch and from small to large, from less to more, from a technical level to the cultural heritage, has experienced rapid development.  However, landscape lighting in the building at the same time, the use of renewable energy lamps are extremely rare, this phenomenon has not aroused people's attention.  After investigation, the authors found that solar landscape lighting source in the area of Tianjin have a deeper level of application.

 1, landscape lighting of the status quo
 According to the survey, as at the end of 2005, Tianjin six districts within the tenure of landscape lighting for the 32,000 number.  One commercial facade of about 24,000, many outdoor advertisements 7000, large-scale lighting facilities (The tower, water parks, theme park, Galaxy Plaza) 46, built a total of 336, a total of 755 China Democratic National Construction Association, the Tour spotlights 11 , Landscape lighting above the total power consumption of about 240,000 kwh.
 From these figures, we can see that the energy cost is enormous. With the global acceleration of the process of industrialization, more and more conventional energy sources can not meet people's production and daily needs, all kinds of new environmentally friendly renewable energy in the proportion of people living in a growing. Ethanol to fuel cars, use of biodegradable starch do lunch boxes, 2006, "the G-8 summit" on the solar cars, are slowly into people's lives.  However, solar energy is still not in the landscape lighting in playing its due role, which has its own reasons also have the constraints of external conditions.

 2, solar energy-related technology

 Solar energy is inexhaustible, and clean and safe, ideal for renewable energy.  After 50 years of development, the current solar photovoltaic technology is becoming mature and sustainable development are the characteristics of renewable energy technologies.
 According to the original project to promote China's green lighting project office of the special survey showed that China's electricity consumption in the entire landscape lighting electricity as a proportion of around 12 percent.  In the summer of 2006, Tianjin electricity load reached 5.93 million kilowatts, remove the reasons for summer air-conditioning and other facilities, landscape lighting energy consumption accounted for 8 percent to 10 percent, the basic national situation and in conformity with.  By electricity consumption growth rate lower than the GDP growth rate of 5 percent conservative, to 2010, China's generating capacity is expected to reach 2.7 trillion kwh, lighting electricity consumption is estimated to need 300 billion kwh over.  If the lighting electricity savings by one percentage point to energy-saving 2 billion to 3 billion kwh, if one-third of lighting electricity conservation, energy-saving will be 100 billion kwh.  Clearly, the energy-saving lighting as the most effective means of energy-saving and environmental protection projects, the slightest not be overemphasized.  In the 1950s, Bell Labs in the United States successfully developed the first practical silicon solar cells, solar energy will be born into a practical photovoltaic power generation technology.  Solar cells based on the principle of the semiconductor PN junction of photovoltaic PV effect is that when objects are light, objects within the charge distribution of a change in the EMF and a current effect.  That is, when sunlight exposure or other optical semiconductor PN junction, will be in there on both sides of the PN junction voltage, called photo-voltage, the PN junction short-circuit, resulting in current.  Solar power generation is that without going through the process of direct solar energy into electric energy generating methods.  It includes photovoltaic power generation, photochemical power generation, power generation and optical sensor-generation biological.  Photovoltaic power generation is the use of solar energy and semiconductor electronic devices to effectively absorb sunlight radiation, and make it directly into the electric power generation, solar power generation today is the mainstream.  People often said of the sunlight power generation is the solar photovoltaic (PV), also known as the solar power generation.

 At present, solar photovoltaic lighting systems in the typical components including matrix photovoltaic panels, batteries, power grids, power-conditioning unit, the exchange load centre, DC / exchange converters, AC / DC converters, DC current regulator, Light and floodlights.  System structure may include only one of several parts, which mainly depends on the source and its different application requirements.

 PV lighting system has three main types of structures, including an independent system (see Figure 1), hybrid systems (see Figure 2) and network and systems. Independent system common in the neighbourhood of streetlights, parking lights and signs of public power grid lighting systems, they usually require batteries, so a high loss of storage repair and maintenance costs.  And network system without batteries, but they want to connect to the Internet, and when the matrix from photovoltaic solar panels in the collection can not meet the needs of the device, the system will draw power from the power grid. And network systems in order to enter the photovoltaic energy matrix board and input from the public network in the energy mix, we need to DC load or load sharing, power unit is the need to exchange or load center, which depends on the type of load. 。 When the matrix is the best photovoltaic panels over the energy demand, some network systems and can be fed back into the energy grid.  Hybrid system will be a lot of power products and storage elements combine in order to meet energy needs, such as network and system and the backup battery connected.  While this complex expensive, but it has greatly enhanced the reliability, in particular, to connect to the public especially when the power grid.

3, restrictions on solar energy application of the factors
 Solar power technology principle of simple, high efficiency, the failure of the wider use of landscape lighting in the main reasons the following:
The current landscape lights are installed in most of the residents on the floor, and the installation of solar light to be placed in the top of the building several groups of solar cells, which are battery transport, are not easy to install, is the most important long-term installation in the upper, Canada Roof bearing the load, likely to cause the roof Louyu, such as cracking phenomenon.
 (2) the existing lamps and not solar cells with matching.  It is understood that the existing House of decorative lights are mainly T8 cold cathode lamps, supplemented by Halide Lamp for lighting, daily power consumption of these lamps are 15 ~ 20 kW. The solar light has specialized batteries, only rely on a set of equipment can not meet their supply requirements needed to install standby power.  2003, in Hexi District of Tianjin Waterfront Road eight buildings on the installation of solar lighting equipment, but six months after the illumination of time and light intensity can not be guaranteed on the.  Although this can not rule out the lights because the aging lines, but solar cells can not be sustained supply is also an important factor.
 (3) of solar energy equipment package of one-time investment is too large. 。 Solar energy-saving equipment despite the significant effect of energy-saving aspects, but the installation of this equipment investment is too large, with only the lamps, cables and more than 60,000 to 70,000 yuan of funds.  Some units that too much input on the initial fear is not enough, but they also can save to invest in doubt. Therefore, the solar energy equipment can not build units in the application.  In addition, because the equipment required to install professionals-spot guidance, but also restricted their wide dissemination.

 4 solution

 Solar cell technology after 50 years of development, has become a mature industry, and a number of investment applications.  In order to better lighting in the landscape in the use of solar energy technology, the author made the following recommendations:
 (1) improving solar cells, its structure is more compact, higher power output.  Solar cells as a new energy, space and development potential is enormous.  To successfully developed the solar cells, to the small, Qiao and spiritual aspects of development, completely abandoned the original kind of big, stupid, the mode of death.
 (2) developing new sources to reduce energy consumption to meet the needs of sustainable lighting.。 Beijing manufacturers have now developed a new type of film with light source, power consumption per hour only 0.5 ~ 1 kW/m2, there are small in size, ease of installation advantages, but also a dynamic changes in the patterns, has now been selected as Beijing 2008 Olympic Games one of the buildings lighting materials.
。 (3) strengthen efforts to publicize, to guide the science and technology.  Solar can be said to be truly green energy, to make people aware of the need to vigorously promote the Government.。 From the innovative technology to put application cycle is generally 10 to 12, solar energy technology and the integration of landscape lighting, for the broad masses of people to create a broader future. Relevant government departments and enterprises should strengthen efforts to publicize, to guide the work of science and technology.
 (4) Government support. China's energy consumption is a big country, the annual economic development and also spent a lot of energy.  Solar energy as a new, energy-saving aspects of a good show. In order to make more effective use of it, the Government should put solar energy technology innovation of enterprises to give incentives for production of solar lighting to help the enterprises, the use of solar lighting units to give subsidies to promote solar energy technology for recognition of the media .