Adjustable. According to relevant public information, the optimal placement angle of floating photovoltaic panels is 45 degrees. When installing solar panels, the first thing to consider is the choice of orientation. If the direction is wrong, it won't do any good, no matter the angle. If it's in the wrong direction, you won't get any sunlight at all. Nowadays, common solar devices, such as solar street lights, are generally chosen facing south, which has been scientifically studied. When the direction of the solar panel faces south, the power generation efficiency is very high. When choosing a direction, you should also pay attention to the impact of surrounding buildings and trees. The photovoltaic system floating on water is composed of photovoltaic panels, transformers, combiner boxes, inverter equipment, power linescollectors, HDPE polyethylene floating frames and other parts.
Aquatic climate factors that affect floating photovoltaic power plants mainly include temperature, precipitation, wind speed, humidity, sunshine hours, thunderstorms, etc.
Affected by factors such as shortage of land resources, water photovoltaic installations are booming. Water and land have different microclimate characteristics (climate within a small range caused by different properties of the underlying surface). the manifestations are temperature, precipitation, wind speed, humidity, hours of sunshine, thunderstorms, etc. will have an impact on photovoltaic power plants.
1. Temperature - the temperature of the body of water is lower than that of the earth
Since the specific heat of the body of water is much higher than that of the earth, whenIf the water and land receive the same amount of solar heat, the temperature of the water body will change smaller than that of the land and solar radiation can penetrate deeper layers of water. The turbulent mixing effect of the water body is strong, which makes the sun. radiation absorbed by the body of water distributed relatively uniformly at the upper and lower levels. This significantly moderates diurnal and annual temperature changes, making the water warmer than land in winter and cooler than land in summer. Of course, the impact of water masses on temperature varies depending on the size and depth of the water bodies, and there are also differences between north and south. The following table takes Dongting Lake and Yuanjiang River as examples. Generally, the lake surface temperature is 0.6-1.8 ℃ lower than the earth surface temperature. The minimum differenceextreme is relatively large, greater than 5℃, and the maximum extreme difference is greater than 1.1℃.
It should also be noted that we have no actual observations of the lake surface. We use data from weather stations near the lake. If we observe it on the surface of the lake, the temperature will definitely be different from this. than on land, the maximum temperature is estimated to be more than 2℃ lower. The highest temperature at the lake is around 40°C, while the surface of the lake can be as low as 38°C. In addition, the temperature at the water surface remains below 25°C for a longer period than at the land surface.
2. Precipitation - precipitation in aquatic areas is less than on land.
Due to the thermal difference between the underlying surfaces of water and land, the stability of the stratification of the temperature is greater in thes waters than on land, so the amount of precipitation on water surfaces is greater than that on land. In summer, the water surface is cool, the stratification is stable, the rain suppression effect is the strongest. and precipitation is the most obvious. For example, the annual precipitation of Dongting Lake is 1,302.4 mm, which is 166.7 mm less than the territory's 1,469.1 mm. The annual precipitation of Poyang Lake is 1,494.3 mm, which is 30.2 mm less than that of the territory. In addition, the number of days of precipitation is about 10 fewer than on land.
The Xin'anjiang Reservoir was built in 1959. Someone specifically conducted a study on precipitation. Precipitation in the reservoir area has decreased by 100 mm, and the center of the reservoir may decrease by more than 150 mm.
3. Wind speed——The wind speed in water is higher than that on land
Since the roughsity of the surface of the water body is smaller than that of the earth, the friction force is undoubtedly lower than that of the earth, so the wind speed of the water surface is higher than that of the land. of the earth. The average wind speed over several years in the waters of Dongting Lake is 2.9 m/s and 2.6 m/s on land, with a difference of 0.3 m/s. The number of wind days is 17.1 days and 8.8 days on land, with a difference. of 8.3 days. The maximum wind speed at the lake surface is not much different from that at the land surface.
4. Relative humidity - changes with the seasons
Compared to that of the earth, the relative humidity of waters is opposite in winter and summer. In winter, the temperature on the continent is low. , the air is saturated, the water vapor pressure is low, and the evaporation water source is still relatively small, so the relative humidity is high. In summer, the temperature on the continent est greater than that of the water surface. Therefore, the air is much less humid than the fresh water surface, and the relative humidity of the water surface is higher than that of land. Since the temperature difference between the lake and land is only 1-2°C, the difference in relative humidity is also very small. For example, the annual average relative humidity of Dongting Lake differs by only 1% (i.e. that of the lake). the surface is 1% larger than the earth's surface), and the maximum difference in summer is only 3%.
5. Daylight Hours: Waters have more daylight hours than land.
Since bodies of water receive less precipitation than land, total cloud cover is usually less than that of the earth. the total cloud cover is 1 less ~ 2%, or about 7% less in summer, so the hours of sunshine are more, the percentaverage sunshine age increases by 3% and increases by 9% in summer, therefore in summer, the average number of clouds. days spent on the water surface last about 30 minutes to 1 hour longer than on land.
6. Thunderstorms - The number of thunderstorm days in waters is less than that on land.
The air in waters is more stable than that on land, so the number of thunderstorm days is less to that on land, generally about 2 to 3 days less. From the above analysis, it can be concluded that water and land surfaces are affected by different underlying surfaces, and there are certain climatic differences, but the difference is not particularly obvious. Low temperatures and hours of sunshine can cause photovoltaic power plants to operate under the sun. same conditions. The power generation capacity on water is greater than that on land, and construction conditions such as speed of vehigh nt must be taken into account during design.
(Source: Photovoltaic Solar Network)