絕大多數(shù)戶用和工商業(yè)光伏都是將光伏組件安裝在屋頂，不僅可以幫助業(yè)主節(jié)省電費，還可以優(yōu)化屋頂空間的使用，
1.為屋頂降溫。
本文將討論在平屋頂上安裝光伏電站必須了解的幾個最重要的事項。
采用哪種安裝形式
不同的屋頂安裝光伏組件的方法也不一樣，常見的安裝方式包括附加型、壓載型及樁基型。
如果屋頂屬于彩鋼瓦型式，一般都考慮附加型，直接將組件平鋪在彩鋼瓦上，尤其是一般彩鋼瓦屋頂都沒有女兒墻，采用平鋪的型式防風(fēng)效果最好，最為安全；另外彩鋼瓦屋頂也有一定的傾角，雖然可能不是光伏發(fā)電對應(yīng)的最佳傾角，但加大傾角帶來的改造成本也是需要綜合考量的。
對于水泥屋頂，通常是純平，常見的安裝方式是壓載型和混凝土基礎(chǔ)樁基型，如上圖所示。
很多時候，建筑物業(yè)主不允許在混凝土平屋頂上鉆孔，一方面是擔(dān)心老建筑的強度，或者是不想改變屋頂?shù)姆浪阅?。這就是選擇壓載型或混凝土基礎(chǔ)安裝的原因。
壓載型由于沒有和屋頂做錨固連接，因此側(cè)面可以考慮做防風(fēng)處理，尤其是沒有女兒墻的水泥屋頂。
混凝土基座的主要目的是確保即使在暴風(fēng)雨季節(jié)，支架系統(tǒng)也能保持完好無損。它保證了良好的安裝而不會導(dǎo)致屋頂漏水，還可以提高太陽能電池組件的效率，減少女兒墻對陽光的遮擋。
2平屋頂不代表平鋪安裝
在平屋頂上采用平鋪方式安裝光伏組件，似乎是最想當(dāng)然的方式，不僅安裝量/面積可以最大化，還有可能將光伏作為屋頂頂棚使用，增加空間面積。
但事實上，在平屋頂上安裝光伏，并不意味著您還應(yīng)該將其傾斜度設(shè)置為0度，我們需要考慮很多因素，應(yīng)避免平裝，包括：平鋪組件容易積灰，積灰可能造成10％甚至30%的發(fā)電量損失；清洗更不方便，積水不易流出；與傾斜安裝相比，發(fā)電量將減少；投資回報期將更長；可能無法靠自然降雨來去除積灰；傾斜安裝和純平鋪的光伏陣列發(fā)電量會有明顯的不同，通過對一個11.2kWp太陽能系統(tǒng)進行仿真模擬，傾角分別為10度、5度和0度。仿真結(jié)果表明，如果傾角為0度，則11.2kWp系統(tǒng)年發(fā)電量約為13,480.3kWh，而在5度傾角下，該系統(tǒng)一年發(fā)電量達到14,066.9kWh。而事實上，當(dāng)傾角為10度時，該系統(tǒng)年發(fā)電量達到14,520kWh。從結(jié)果中可以看出，每增加5度，系統(tǒng)每年增加500kWh的發(fā)電量（15度后，增加量會明顯減少，超過最佳傾角后反而會更低）。而且，上述仿真模擬還沒有考慮低傾角安裝時由于積灰而造成的發(fā)電量損失。
建議如果不愿意采用最佳傾角來安裝的話，安裝傾角盡可能還是高一些。如果必須平鋪，建議也將傾角設(shè)計在5-10度之間。對于平屋頂來說，5-10度的角度也已經(jīng)足夠平了，而對于彩鋼瓦屋頂來說，一般都會留有3度以上的角度，相比增加傾角的額外成本來說，順其自然、隨坡就勢也是很好的選擇。
3平屋頂安裝必須考慮風(fēng)速
在太陽能系統(tǒng)的設(shè)計階段，必須考慮當(dāng)?shù)乜赡艹霈F(xiàn)的最大風(fēng)速，尤其是在風(fēng)速超過每小時180公里的地區(qū)。
不是五年一遇，十年一遇，光伏系統(tǒng)的壽命是25年，必須考慮50年一遇！
去年4月發(fā)生在江蘇南通的臺風(fēng)足以說明一切，隨著建筑質(zhì)量的提升，對于南通地區(qū)的建筑也來說，幾乎沒有人會過多考慮到三十年前常發(fā)生的臺風(fēng)災(zāi)害，畢竟南通地區(qū)的臺風(fēng)，也就能對以前的平方、草屋、大棚帶來點影響。
但南通的那場大風(fēng)，卻活生生地將屋頂?shù)奶柲芄夥?、太陽能熱水器都吹到了地上，臺風(fēng)期間造成十多人死亡，50年一遇毫不夸張。
普通的平屋頂太陽能發(fā)電系統(tǒng)可以承受160 km/h（十三級臺風(fēng)）的風(fēng)速，但如果沒有女兒墻擋風(fēng)，陣列間沒有考慮防風(fēng)，局部區(qū)域因氣流而造成的瞬間風(fēng)速會遠遠超過實際的風(fēng)速。
這時候?qū)τ谥Ъ艿倪x型、結(jié)構(gòu)設(shè)計、壓載或混凝土基礎(chǔ)強度設(shè)計必須依賴專業(yè)機構(gòu)的建議，即便是彩鋼瓦屋頂?shù)钠戒仯惨锌茖W(xué)的分析。(來源 | 光伏能源圈)

The vast majority of domestic and commercial photovoltaics are rooftop panels, which not only help homeowners save money on their electricity bills, but also optimize the use of roof space,

Step 1 Cool the roof.

This article will discuss some of the most important things to know when installing a photovoltaic plant on a flat roof.

What kind of installation is used

Different rooftop installation methods of photovoltaic modules are also different. Common installation methods include additional type, ballast type and pile type.

If the roof belongs to the caigang tile type, generally consider the additional type, directly tile components on the Caigang tile, especially the general Caigang tile roof has no parapet, the tiling type of windproof effect is the best, the most safe; In addition, the color steel tile roof also has a certain Angle, although it may not be the best Angle corresponding to photovoltaic power generation, but the transformation cost caused by increasing the Angle also needs to be comprehensively considered.

For cement roofs, which are usually flat, the common installation methods are ballast and concrete foundation pile foundations, as shown in the image above.

In many cases, building owners are not allowed to drill into flat concrete roofs because of concerns about the strength of the old building or because they do not want to change the waterproof properties of the roof. This is the reason for the choice of ballast type or concrete foundation installation.

The ballast type is not anchored to the roof, so the side can be considered to be windproof, especially the cement roof without parapet.

The main purpose of the concrete base is to ensure that the support system remains intact even during stormy seasons. It ensures a good installation without causing the roof to leak. It also improves the efficiency of the solar cell modules and reduces the shade of the parapet from the sun.

2 Flat roof does not mean tile installation

It seems to be the most natural way to install PV modules on the flat roof by tiling. Not only can the installation volume/area be maximized, but also the PV can be used as the roof roof to increase the space area.

But in fact, installing PV on a flat roof does not mean that you should also set its slope to 0 degrees. There are many factors to consider and flat installation should be avoided, including: tiled components are prone to ash accumulation, which may cause 10% or even 30% loss of power generation; Cleaning is more inconvenient, water is not easy to flow out; Compared with the tilt installation, the power generation will be reduced; The payback period will be longer; Natural rainfall may not be able to remove ash; There is a significant difference in the amount of power generated by the sloped and flat-laid PV arrays, as simulated by an 11.2kwP solar system with inclination angles of 10 degrees, 5 degrees and 0 degrees, respectively. The simulation results show that, if the inclination Angle is 0 degrees, the annual power generation of 11.2kwP system is about 13,480.3kWh, and under the 5 degrees inclination Angle, the unified annual power generation of the system reaches 14,066.9kWh. In fact, at an Angle of 10 degrees, the system generates 14,520kWh a year. From the results, it can be seen that the system increases the power generation by 500kWh per year for every 5 degrees of increase (after 15 degrees, the increase will be significantly reduced, but even lower after exceeding the optimal Angle). Moreover, the above simulation does not take into account the power generation loss due to ash accumulation during low-angle installation.

It is recommended that if you are not willing to use the best Angle to install, the installation Angle is as high as possible. If tiling is necessary, it is recommended that the inclination Angle be between 5 and 10 degrees. For the flat roof, 5-10 degrees Angle has been flat enough, and for the color steel tile roof, generally will leave more than 3 degrees of Angle, compared to increase the extra cost of inclination, let nature take its course, with the slope is also a good choice.

Wind speed must be considered in flat roof installation

In the design phase of solar systems, the maximum local wind speeds that are likely to occur must be considered, especially in areas with wind speeds exceeding 180 kilometers per hour.

Not once in five years, once in ten years, PV system life is 25 years, must consider once in 50 years!

The typhoon that happened in Nantong, Jiangsu Province in April last year is enough to illustrate everything. With the improvement of construction quality, for the buildings in Nantong area, almost no one will take too much account of the typhoon disaster that often happened 30 years ago. After all, the typhoon in Nantong area can also bring some impact on the square, grass huts and greenhouses in the past.

However, the wind in Nantong blew the solar photovoltaic and solar water heater on the roof to the ground. During the typhoon, more than 10 people died, which was the first time in 50 years.

Ordinary flat roof solar power generation system can withstand the wind speed of 160 km/h (class 13 typhoon), but if there is no parapet windscreen, the array does not consider the wind protection, the local area due to airflow caused by the instantaneous wind speed will be far more than the actual wind speed.

At this time for bracket selection, structural design, ballast or concrete foundation strength design must rely on the advice of professional institutions, even if the tile roof of color steel tile, there should be a scientific analysis. Photovoltaic energy source (| circle)