Photovoltaic BIPV Waterproof System

BIPV (Building Integrated Photovoltaics) is a technology that integrates solar photovoltaic modules with building envelopes (such as roofs, curtain walls, sunshades, etc.). Its core is to allow photovoltaic modules to simultaneously undertake the dual functions of "power generation" and "building envelope". The waterproofing system is a key subsystem of BIPV, which is directly related to building structural safety (preventing water leakage from damaging the building), photovoltaic module life (avoiding moisture and short circuits), and power generation efficiency (reducing downtime due to failures).

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Details Introduction

BIPV（建筑光伏一体化）是将太阳能光伏组件与建筑围护结构（如屋顶、幕墙、遮阳棚等）集成的技术，其核心是让光伏组件同时承担 “发电” 和 “建筑外围护” 双重功能。而 防水系统是 BIPV 的关键子系统 ，直接关系到建筑结构安全（防止漏水损坏建筑）、光伏组件寿命（避免受潮短路）及发电效率（减少因故障导致的停机）。以下从重要性、设计原则、系统类型、核心组成、施工要点等方面详细介绍：

一、BIPV 防水系统的核心重要性

BIPV 组件与建筑结构的连接部位、组件之间的接缝是雨水渗透的高风险点。若防水失效，会导致：

建筑安全隐患 ：雨水渗入建筑内部，侵蚀钢筋、墙体，降低结构耐久性；
光伏系统损坏 ：组件内部受潮短路，电路故障，发电效率骤降甚至报废；
维护成本激增 ：漏水修复需拆除部分组件，不仅影响发电，还可能破坏原有防水结构，形成恶性循环。

二、BIPV 防水系统的设计原则

BIPV 防水需兼顾 “建筑防水” 与 “光伏功能”，设计时需遵循以下原则：

协同性 ：与建筑主体防水等级（如 GB 50108《地下工程防水技术规范》）匹配，同时适配光伏组件的安装方式（如平铺、斜铺、镶嵌等）；
多层次防护 ：采用 “防排结合” 策略 —— 优先通过密封、结构设计阻止雨水渗入，少量渗入的雨水通过排水构造及时排出，避免积水；
耐候性与兼容性 ：材料需耐受紫外线、高低温（-40℃~80℃）、风雨侵蚀，且与光伏组件（玻璃、金属边框）、建筑结构（混凝土、金属屋面）兼容，避免化学腐蚀或物理老化；
可维护性 ：设计时预留检查、维修通道（如可开启的组件单元），避免因维护破坏防水结构。

三、常见 BIPV 防水系统类型（按安装场景分类）

BIPV 的安装场景主要为屋顶和幕墙，两者防水系统因受力、排水方向不同而存在差异：

1. 屋顶 BIPV 防水系统

屋顶是 BIPV 最常见的应用场景（如平屋顶、坡屋顶、金属屋面），防水核心是 “阻止雨水渗透至屋面结构层”，并配合排水设计。

平屋顶 BIPV ：
光伏组件通常通过支架架空或直接粘贴在屋面防水层上。防水重点包括：

组件与屋面基层的密封：采用丁基胶带、防水卷材（如 TPO、PVC）覆盖组件边缘与屋面的缝隙；
支架与屋面的连接点：通过防水垫片（如 EPDM 橡胶）、密封圈密封，避免螺栓穿透屋面防水层后漏水；
排水设计：组件间预留 5°~10° 坡度，搭配铝合金导水槽，将雨水引至屋面排水口。

坡屋顶 BIPV ：
常与瓦片（如沥青瓦、陶瓷瓦）结合，防水重点在 “组件与瓦片的搭接” 和 “屋檐排水”：

组件下铺设防水垫层（如 SBS 改性沥青卷材），作为二道防线；
组件与瓦片搭接长度≥100mm，搭接处用耐候密封胶密封；
屋檐处设置挡水条和排水槽，避免雨水沿组件下沿渗入檐口。

金属屋面 BIPV ：
光伏组件直接固定在金属屋面板（如彩钢板）上，防水利用金属屋面自身的 “咬合式结构防水” 特性：

组件与金属板的连接点采用专用金属夹具，配合丁基胶带密封，避免破坏金属板的咬合边；
组件间接缝与金属板的波峰 / 波谷对齐，利用金属板的排水坡度将雨水导走。

2. 幕墙 BIPV 防水系统

幕墙 BIPV（如玻璃幕墙、石材幕墙集成光伏组件）为垂直或倾斜安装，雨水渗透风险低于屋顶，但需防止雨水沿组件缝隙渗入室内。防水重点包括：

组件接缝密封 ：采用双道密封设计 —— 内侧用结构胶（承担受力），外侧用耐候密封胶（阻止雨水），胶缝宽度≥5mm，深度为宽度的 1/2~2/3（避免三面粘结导致开裂）；
框体与建筑结构连接 ：幕墙框架与墙体之间预留间隙，填充防火岩棉后，外侧用防水密封胶 + 金属盖板密封，内侧设置泄水孔（排出渗入的少量雨水）；
转角与开启扇处理 Add waterproof gaskets at the internal and external corners, use multiple seals (such as EPDM rubber strips) for the opening sash (such as openable photovoltaic modules), and set up drainage grooves to direct rainwater outdoors.

IV. Core Components of BIPV Waterproof System

Regardless of the scenario, the BIPV waterproof system consists of Sealing system 、 Drainage system 、 Structural waterproofing Three core components:

Components	Core functions	Common materials / structures
Sealing system	Prevent rainwater from directly penetrating joints / connections	Silicone weather-resistant sealant (UV resistant, high and low temperature resistant), butyl tape (strong initial adhesion, long-term sealing), waterproof gasket (EPDM rubber, for bracket connection points)
Drainage system	Discharge a small amount of infiltrated rainwater to avoid water accumulation	Aluminum alloy water guide trough (roof), drainage holes (curtain wall frame), slope design (≥3°, to ensure water flow direction)
Structural waterproofing	Use the physical form of components / building structure for leak prevention	Component overlapping design (overlapping length ≥50mm), metal occlusal edge (similar to metal roof), drainage of profiled plate crest

V. Key Points for Construction and Maintenance

Construction control ：

The base layer needs to be cleaned (remove oil, dust) before the sealant is applied to ensure it is dry and to avoid air bubbles or false adhesion;
The components must be installed flat and the joints aligned to ensure that the sealant / overlapping parts are evenly stressed;
The drainage slope should be strictly implemented according to the design (such as roof ≥3°, curtain wall vertical drainage groove slope ≥1%).

Maintenance management ：

Regularly check whether the sealant is cracked or aging (recommended every 2~3 years), and repair or replace it in time;
Clean debris (such as fallen leaves, dust) from the drainage ditch / holes to ensure smooth drainage;
When replacing components, protect the original waterproof structure and reseal the joints.

Summary

The BIPV waterproof system is a key link between "building protection" and "photovoltaic function". Its design needs to be combined with the characteristics of the scene. Through multiple protections of "sealing + drainage + structure", the materials need to meet weather resistance and compatibility, and the construction and maintenance need to be refined control. Only in this way can we ensure the long-term safe and efficient operation of the BIPV system