Racking system to attach modules vertically to a wall?

Mounting photovoltaic (PV) panels vertically on a wall presents unique challenges, especially in locations exposed to extreme wind speeds. Oftentimes, architects will design in a solar facade, but not provide the underlying mounting design. Whether you use an approved solar product or unistrut, you will need to employ a structural engineer to develop load and stress calculations for your application and then eventually review and seal the construction documents. Here are some important considerations and potential solutions for your situation:

Approved Vertical Mounting Systems

While most commercial PV racking systems are designed for rooftop or ground-mounted installations with limited tilt angles, a few manufacturers offer solutions specifically approved for vertical mounting:

1. **IronRidge XR1000**: This system is known for its robustness and can be adapted for vertical wall installations. It's crucial to verify with the manufacturer regarding specific wind load certifications.

2. **SunModo SunBeam**: This system has been used for vertical applications and offers flexibility for various mounting configurations.

3. **UniRac**: They offer custom solutions that might be adapted for vertical mounting. Contacting them for specific product recommendations is advisable.

Key Considerations for Vertical Mounting

1. **Wind Load**: Vertical panels can experience significant wind loads, especially in extreme conditions. Ensure the racking system is rated for the maximum expected wind speeds in your area. This may require consulting with a structural engineer.

2. **Panel Orientation**: While performance may not be your primary concern, the orientation of panels can still affect efficiency. Vertical mounting generally results in reduced energy production compared to angled installations. Ensure the panels are installed securely to prevent movement and potential damage.

3. **Mounting Hardware**: You may have to pay extra attention to vibration and thermal expansion for vertical mounting. All fasteners should be rated for vibration and thermal applications - for example, aircraft nuts or similar:

   - **Material and Corrosion Resistance**: Choose stainless steel or galvanized steel to prevent rust and corrosion, especially in harsh weather conditions.

   - **Proper Anchoring**: Securely anchor the Unistrut to the wall structure. The wall must be capable of bearing the additional load.

   - **Spacing and Support**: Ensure adequate spacing between supports to distribute the load evenly and prevent sagging.

4. **Panel Clearance**: Maintain a gap between the wall and the panels to allow airflow and prevent heat buildup, which can affect panel efficiency and longevity.

5. **Maintenance Access**: Ensure there is sufficient access for maintenance and cleaning, as vertical panels can accumulate debris and require regular upkeep.

6. **Compliance with Local Codes**: Check with local building codes and regulations to ensure your installation meets all safety and structural requirements.

### Using Unistrut for Mounting

If you decide to use Unistrut, follow these guidelines:

1. **Load Calculation**: Calculate the total load, including the weight of the panels, racking, and potential wind forces. Ensure the Unistrut system can handle these loads.

2. **Attachment Points**: Use strong anchors such as expansion bolts or concrete screws to attach the Unistrut to the wall.

3. **Cross Bracing**: Implement cross bracing to increase the rigidity of the structure and reduce the risk of movement due to wind - this becomes more important the further out from the wall the array hangs off the underlying structure.

### Final Recommendations

- **Consult a Structural Engineer**: Before proceeding with the installation, it's imperative to consult with a structural engineer to verify that the wall and mounting system can safely support the PV panels under all expected conditions.

- **Manufacturer's Guidance**: Always refer to the manufacturer's installation manuals and guidelines to ensure proper and safe installation.