01采用哪种安装形式

不同的屋顶安装光伏组件的方法也不一样，常见的安装方式包括附加型、压载型及桩基型。

如果屋顶属于彩钢瓦型式，一般都考虑附加型，直接将组件平铺在彩钢瓦上，尤其是一般彩钢瓦屋顶都没有女儿墙，采用平铺的型式防风效果最好，最为安全；另外彩钢瓦屋顶也有一定的倾角，虽然可能不是光伏发电对应的最佳倾角，但加大倾角带来的改造成本也是需要综合考量的。

对于水泥屋顶，通常是纯平，常见的安装方式是压载型和混凝土基础桩基型，如图所示。

很多时候，建筑物业主不允许在混凝土平屋顶上钻孔，一方面是担心老建筑的强度，或者是不想改变屋顶的防水性能。这就是选择压载型或混凝土基础安装的原因。

压载型由于没有和屋顶做锚固连接，因此侧面可以考虑做防风处理，尤其是没有女儿墙的水泥屋顶。

混凝土基座的主要目的是确保即使在暴风雨季节，支架系统也能保持完好无损。它保证了良好的安装而不会导致屋顶漏水，还可以提高太阳能电池组件的效率，减少女儿墙对阳光的遮挡

02平屋顶不代表平铺安装

在平屋顶上采用平铺方式安装光伏组件，似乎是最想当然的方式，不仅安装量/面积可以最大化，还有可能将光伏作为屋顶顶棚使用，增加空间面积。

但事实上，在平屋顶上安装光伏，并不意味着您还应该将其倾斜度设置为0度，我们需要考虑很多因素，应避免平装，包括：

l 平铺组件容易积灰，积灰可能造成10％甚至30%的发电量损失；

l 清洗更不方便，积水不易流出；

l 与倾斜安装相比，发电量将减少；

l 投资回报期将更长；

l 可能无法靠自然降雨来去除积灰；

倾斜安装和纯平铺的光伏阵列发电量会有明显的不同，通过对一个11.2kWp太阳能系统进行仿真模拟，倾角分别为10度、5度和0度。

仿真结果表明，如果倾角为0度，则11.2kWp系统年发电量约为13,480.3kWh，而在5度倾角下，该系统一年发电量达到14,066.9kWh。而事实上，当倾角为10度时，该系统年发电量达到14,520kWh。

从结果中可以看出，每增加5度，系统每年增加500kWh的发电量（15度后，增加量会明显减少，超过最佳倾角后反而会更低）。而且，上述仿真模拟还没有考虑低倾角安装时由于积灰而造成的发电量损失。

如果不愿意采用最佳倾角来安装的话，安装倾角尽可能还是高一些。如果必须平铺，建议也将倾角设计在5-10度之间。对于平屋顶来说，5-10度的角度也已经足够平了，而对于彩钢瓦屋顶来说，一般都会留有3度以上的角度，相比增加倾角的额外成本来说，顺其自然、随坡就势也是很好的选择。

很多时候，建筑物业主不允许在混凝土平屋顶上钻孔，一方面是担心老建筑的强度，或者是不想改变屋顶的防水性能。这就是选择压载型或混凝土基础安装的原因。

压载型由于没有和屋顶做锚固连接，因此侧面可以考虑做防风处理，尤其是没有女儿墙的水泥屋顶。

混凝土基座的主要目的是确保即使在暴风雨季节，支架系统也能保持完好无损。它保证了良好的安装而不会导致屋顶漏水，还可以提高太阳能电池组件的效率，减少女儿墙对阳光的遮挡

都会留有3度以上的角度，相比增加倾角的额外成本来说，顺其自然、随坡就势也是很好的选择。

03平屋顶安装必须考虑风速

在太阳能系统的设计阶段，必须考虑当地可能出现的最大风速，尤其是在风速超过每小时180公里的地区。

不是五年一遇，十年一遇，光伏系统的寿命是25年，必须考虑50年一遇！

2021年4月底发生在江苏南通的台风足以说明一切，随着建筑质量的提升，对于南通地区的建筑也来说，几乎没有人会过多考虑到三十年前常发生的台风灾害，毕竟南通地区的台风，也就能对以前的平方、草屋、大棚带来点影响。

但发生在南通的那场大风，活生生地将屋顶的太阳能光伏、太阳能热水器都吹到了地上，台风期间造成十多人死亡，50年一遇毫不夸张。

普通的平屋顶太阳能发电系统可以承受160 km / h（十三级台风）的风速，但如果没有女儿墙挡风，阵列间没有考虑防风，局部区域因气流而造成的瞬间风速会远远超过实际的风速。

这时候对于支架的选型、结构设计、压载或混凝土基础强度设计必须依赖专业机构的建议，即便是彩钢瓦屋顶的平铺，也要有科学的分析。

04平屋顶安装的漏水风险

积水在平屋顶上很常见。由于屋顶是平坦的，所以水无处可去，或者说排水变慢，在屋顶停留的时间会边长，因此，任何屋顶上的缝隙、孔洞都会变成积水的停留处。

此时，安装了光伏系统的平屋顶，由于支架安装和混凝土桩基安装时可能造成的防水层破坏，就成为平屋顶光伏最大的漏水风险。

如果是彩钢瓦屋顶，采用夹具安装要比在彩钢瓦上打孔要好；如果彩钢瓦不适合用夹具连接，采用结构胶粘结也是一种选择。

05需要考虑平屋顶上的机械单元

在水泥平屋顶上设计和安装光伏的挑战之一是现有建筑楼顶的各类机械装置，如室外空调机组、排水管、排气扇、通风设施、水箱、栏杆、屋顶结构、暖通系统和水管等等。

这些已有的设备，不仅影响了屋顶光伏的布局，影响了系支架间距和排列，还可能对光伏阵列产生阴影遮挡，或是影响到日后的运维。

有的设计人员会考虑在这些设施上方加装光伏，为设施遮风挡雨，但由此带来的另一个问题是高度设计要求和防风要求，以及运维的困难。

对于屋顶设施，只能因地制宜地开展设计，但这是屋顶光伏无法回避，必须重视的问题。

06屋顶平铺组件的增发

一般没有绝对0度角的平铺安装，但低倾角确实是不能回避的问题，即便是水泥屋顶也会有这样的需求。

对于屋顶平铺光伏，优化设计后仍然可以获得最佳发电能力，这可以通过不同的方式来完成。

Which installation method is used for 01
The method of installing photovoltaic modules on different roofs also varies, and common installation methods include additional, ballast, and pile foundation types.
If the roof belongs to the color steel tile type, the additional type is generally considered, and the components are directly laid on the color steel tile. In particular, the general color steel tile roof has no Parapet, and the flat type is the best and safest for wind protection; In addition, the color steel tile roof also has a certain inclination angle. Although it may not be the optimal inclination angle for photovoltaic power generation, the renovation cost brought about by increasing the inclination angle also needs to be comprehensively considered.
For cement roofs, they are usually flat, and the common installation methods are ballast type and concrete foundation pile foundation type, as shown in the figure.
In many cases, building owners are not allowed to drill holes on the concrete Flat roof. On the one hand, they are worried about the strength of the old building or do not want to change the waterproof performance of the roof. This is the reason for choosing ballast type or concrete foundation installation.
Since the ballast type is not anchored to the roof, wind proof treatment can be considered for the side, especially for the cement roof without Parapet.
The main purpose of the concrete foundation is to ensure that the support system remains intact even during stormy seasons. It ensures good installation without causing water leakage on the roof, improves the efficiency of solar cell modules, and reduces the Parapet's blocking of sunlight
02 Flat roof does not mean flat installation
It seems to be the most natural way to install photovoltaic modules on Flat roof in the way of tiling. Not only can the installation amount/area be maximized, but also it is possible to use photovoltaic as a roof ceiling to increase the space area.
However, the fact that photovoltaic is installed on a Flat roof does not mean that you should also set its inclination to 0 degrees. We need to consider many factors, including:
Tiled components are prone to dust accumulation, which may result in a 10% or even 30% loss of power generation;
Cleaning is more inconvenient, and accumulated water is not easy to flow out;
Compared to inclined installation, the power generation will be reduced;
The investment return period will be longer;
It may not be possible to rely on natural rainfall to remove accumulated ash;
There will be obvious differences between the power generation of tilted and flat Photovoltaic system. Through the simulation of an 11.2kWp solar system, the tilt angles are 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 the 11.2kWp system is about 13480.3kWh, while at a 5 degree inclination angle, the annual power generation of the system reaches 14066.9kWh. In fact, when the inclination angle is 10 degrees, the annual power generation of the system reaches 14520kWh.
From the results, it can be seen that for every 5 degree increase, the system generates an annual increase of 500kWh of electricity (after 15 degrees, the increase will significantly decrease, but after exceeding the optimal inclination angle, it will actually be lower). Moreover, the above simulation has not yet taken into account the power generation loss caused by ash accumulation during low inclination installation.
If you are not willing to use the optimal inclination angle for installation, the installation inclination angle should be as high as possible. If it is necessary to lay flat, it is recommended to also design the inclination angle between 5 and 10 degrees. For Flat roof, 5-
03 Wind speed must be considered for installation of Flat roof
In the design phase of solar systems, it is necessary to consider the maximum wind speed that may occur locally, especially in areas with wind speeds exceeding 180 kilometers per hour.
Not once every five years, once every ten years. The lifespan of the photovoltaic system is 25 years, and a once every 50 years must be considered!
The typhoon that occurred in Nantong, Jiangsu at the end of April 2021 is a testament to everything. With the improvement of building quality, almost no one would think too much about the frequent typhoon disasters that occurred thirty years ago for buildings in the Nantong area. After all, typhoons in the Nantong area can also have some impact on the square, thatched houses, and greenhouses of the past.
But the strong wind that occurred in Nantong vividly blew the solar photovoltaic and solar water heaters on the roof to the ground, causing more than ten deaths during the typhoon, which is no exaggeration.
The ordinary Flat roof solar power generation system can withstand the wind speed of 160 km/h (Level 13 typhoon), but if there is no Parapet to wind, and wind protection is not considered between arrays, the instantaneous wind speed caused by airflow in local areas will far exceed the actual wind speed.
At this point, the selection of brackets, structural design, ballast or concrete foundation strength design must rely on the advice of professional institutions, even for the flat laying of colored steel tile roofs, there must be scientific analysis.
04 Water leakage risk of Flat roof installation
Ponding is common on Flat roof. Due to the flat roof, there is no place for water to go, or the drainage slows down, and the time spent on the roof will be longer. Therefore, any gaps or holes in the roof will become a place for stagnant water to stay.
At this time, for the Flat roof with photovoltaic system installed, the waterproof layer may be damaged during the installation of support and concrete pile foundation, which becomes the biggest risk of water leakage for Flat roof photovoltaic.
If it is a colored steel tile roof, using fixtures for installation is better than drilling holes on the colored steel tile; If colored steel tiles are not suitable for connecting with fixtures, using structural adhesive bonding is also an option.
05 Mechanical units on Flat roof need to be considered
One of the challenges of designing and installing photovoltaic on the cement Flat roof is the various mechanical devices on the roof of the existing building, such as outdoor air conditioning units, drainage pipes, Whole-house fan, ventilation facilities, water tanks, railings, roof structures, HVAC systems and water pipes.
These existing equipment not only affect the layout of roof photovoltaic, affect the spacing and arrangement of tie brackets, but also may have a shadow on the Photovoltaic system, or affect future operation and maintenance.
Some designers may consider installing photovoltaics above these facilities to provide shelter from wind and rain, but another issue that arises is the height design requirements and wind protection requirements, as well as the difficulty of operation and maintenance.
For rooftop facilities, design can only be carried out according to local conditions, but this is an issue that cannot be avoided by rooftop photovoltaics and must be taken seriously.
06 Additional issuance of roof tile components
Generally, there is no absolute 0 degree flat installation, but low inclination is indeed an unavoidable problem, even for cement roofs.
For rooftop tiled photovoltaics, optimized design can still achieve optimal power generation capacity, which can be achieved through different methods.