5D TECH Insights: Application and Design Considerations of CdTe Power-Generating Glass in Photovoltaic Curtain Walls

With the rapid development of green buildings, zero-carbon buildings, and BIPV (Building-Integrated Photovoltaics) technology, photovoltaic curtain walls are becoming an important solution for energy-efficient buildings and renewable energy applications. Among them, power-generating glass based on Cadmium Telluride (CdTe) thin-film technology is emerging as a key solution in the field of photovoltaic architecture due to its excellent low-light power generation capability, stability, and seamless integration with building designs.

As a company focused on renewable energy technology applications, 5D TECH continuously follows the development trends of BIPV technology and promotes the integration of solar power generation technology with architectural aesthetics and functional requirements.

1. Impact of CdTe Power-Generating Glass Dimensions on Photovoltaic Curtain Wall Design

Currently, the size of CdTe power-generating glass is still subject to certain limitations due to manufacturing process constraints. During the design of photovoltaic curtain wall projects, factors such as glass specifications, curtain wall grid design, and the feasibility of customized production must be fully considered.

The current standard size of CdTe power-generating glass is generally:

• 1200mm × 600mm

• Future product sizes are expected to expand to 1200mm × 1800mm

Since the glass panels used in building curtain walls are usually larger than standard photovoltaic glass sizes, multiple pieces of power-generating glass often need to be combined together.

When the curtain wall glass width is:

• ≤1200mm: Only one-directional splicing along the 600mm side is required, resulting in fewer visible seams.

• ＞1200mm: Additional splicing in another direction is required, which not only affects the overall visual appearance but also increases the complexity of the internal electrical connection system.

Therefore, during photovoltaic curtain wall design, architects should consider building aesthetics, material utilization efficiency, and production costs. Standardized product dimensions or integer-multiple combinations are recommended.

Recommended dimensions include:

• L1200 × W1200mm

• L1200 × W1800mm

• L1200 × W2400mm

• L1200 × W3000mm

Using standardized dimensions can effectively reduce cutting waste, improve production efficiency, and optimize overall project costs.

2. Relationship Between Transparency and Power Generation Efficiency of Transparent PV Curtain Walls

For transparent photovoltaic curtain walls, a balance must be achieved between natural lighting requirements and power generation performance.

Generally:

The higher the transparency of photovoltaic glass, the more natural light enters the building; however, the power output per unit area decreases accordingly.

Therefore, practical applications require comprehensive consideration of building functions, daylighting requirements, and energy goals.

Currently, photovoltaic curtain wall projects generally recommend using CdTe power-generating glass with approximately 40% transparency, which provides a good balance between indoor lighting and renewable energy generation.

5D TECH believes that with continuous improvements in photovoltaic glass manufacturing technologies, higher-efficiency and higher-transparency photovoltaic products will further accelerate the development of the BIPV market.

3. Building-Material-Like Photovoltaic Glass for Non-Transparent Areas

For non-transparent areas such as building spandrel walls, photovoltaic glass with decorative building-material effects can be applied, including:

• Aluminum panel imitation finishes

• Stone-like finishes

• Customized colors and textures

These products maintain architectural consistency while providing solar power generation capabilities, transforming traditional building envelopes into green energy-generating surfaces.

4. Structural Design of Photovoltaic Curtain Wall Modules

According to building functions, installation height, safety requirements, and energy-saving standards, photovoltaic curtain wall modules can adopt various structural configurations, including:

• Double-glass laminated structures

• Triple-glass laminated structures

• Single cavity laminated Low-E structures

• Double cavity laminated Low-E structures

The glass thickness must comply with building curtain wall safety requirements while ensuring:

• Wind pressure resistance

• Fire safety performance

• Thermal insulation performance

• Sound insulation performance

5D TECH continues to explore the integration of photovoltaic modules with building application scenarios, providing more possibilities for future smart and sustainable buildings.

5. Installation Methods and Junction Box Design for Photovoltaic Curtain Walls

Photovoltaic curtain wall modules can adopt various installation methods, including:

• Stick (exposed frame) curtain walls

• Unitized/hidden frame curtain walls

• Semi-hidden frame curtain walls

• Point-supported curtain walls

When using exposed frame curtain wall systems, special attention should be paid to the following:

The decorative frame components may cover part of the solar cells, reducing the effective power generation area and potentially creating electrical safety concerns.

Therefore, photovoltaic materials are generally not recommended in areas covered by exposed frame structures.

In such cases, the actual effective cell area of the module will change. When calculating energy output, the actual rated power and conversion efficiency of the photovoltaic curtain wall module should be considered instead of simply calculating based on the total glass area.

6. Junction Box Location Affects the Overall Appearance of Photovoltaic Curtain Walls

In transparent photovoltaic curtain wall designs, the junction box is usually positioned on:

• The long side

• The short side

to achieve concealed wiring and improve architectural aesthetics.

The location of the junction box not only affects the visual appearance of the building but also influences curtain wall system details, cable routing, and future maintenance.

Therefore, at the early design stage, architects, curtain wall engineers, and photovoltaic system suppliers should work together for integrated planning.

7. 5D TECH Driving the Future Development of Photovoltaic Architecture

Currently, photovoltaic curtain walls account for a relatively small share of the building market, with a penetration rate of less than 10%. However, driven by global energy transformation, carbon reduction targets, and the increasing demand for zero-carbon buildings, the photovoltaic curtain wall market is expected to experience significant growth.

As one of the most representative forms of photovoltaic architecture, BIPV not only reduces building energy consumption but also utilizes building surfaces for renewable energy generation, transforming buildings from energy consumers into energy producers.

5D TECH is committed to promoting the integration of renewable energy technologies and green building development. Through advanced photovoltaic and energy storage solutions, 5D TECH provides technical support for future low-carbon cities.

In the future, with the maturity of CdTe power-generating glass technology, declining production costs, and the evolution of architectural design concepts, photovoltaic curtain walls will demonstrate greater market potential in commercial buildings, public facilities, and urban renewal projects.