Mounting systems are essential for the appropriate design and function of a solar photovoltaic system. They provide the structural support needed to sustain solar panels at the optimum tilt, and can even affect the overall temperature of the system. Based on the selection of the solar mounting structure, the cooling mechanism will vary. Ground-mounted solar panels will have better airflow from both sides; therefore, they will cool off easier than roof-mounted panels, and this difference will affect the overall temperature control of solar panels and their efficiency.
Furthermore, the decision on the most appropriate type of solar panel mounting system will also affect the final cost of the project. The installation of the roof mounting may even imply modifications to your house structure that could increase upfront costs.
Moreover, depending on the mounting system that you use, the efficiency of the solar system can increase or decrease, as ground-mounted systems provide better tilt manoeuvrability than roof-mounted panels, and therefore, affect the total power output that your solar system will provide throughout the year. It is important to know which type of solar panel mounting system is the best one for you.
This article explains each available option. After reading this article, you will be able to choose the option that best suits your needs and expectations.
Ground Mounted Solar Systems
As the name implies, your solar system will be located on the ground. The main advantage of a ground-mounted system is that there is a wide range of options to choose from, depending on your location, your needs, and your proposed design.
The various ground-mounted solar racking options that you can choose from are:
- Foundation Mounts
Foundation mounts are the most common ground-mounted structures.
Their installation consists of first preparing the land for excavation. Excavation is needed to put vertical pipes or mechanical tubing surrounded by a concrete foundation in place.
This installation requires the site assessment and geotechnical analysis of the soil to determine whether it is strong enough to hold the mounting structure. Depending on the type of soil (crystalline bedrock, sedimentary rock, gravel, sand, etc.), the foundation pressure will differ. So the soil type determines whether concrete foundation, helical pile, or ground screws are needed to anchor the solar system in place.
- Ballasted Footing Mounts
If the soil is not suitable for drilling or excavation, the best solution is to use a ballast mount system. Ballast mounting consists of a pre-cast concrete block anchored to the ground. This structure is widely used in residential solar panel installations
- Pole Mounts
These represent a simple and cost-effective solution when installing a small solar system. Solar panel pole mounts are ideal for residential purposes. The advantage of pole mounting is that there is no need to create a complicated foundation or level the land (a necessary step for ballasted mounts). Instead, just a simple steel pole with a concrete anchor is placed on the ground. This simple structure provides sufficient support for the solar panels. In some cases, due to the unsuitable soil type or extreme weather conditions, special adjustments are required.
Among the available pole-mounted schemes, you will often find Side Pole Mounts. These mounts are widely used for lightning purposes and very small solar panel installations. Other options are Top Pole Mounts, which are generally designed with heavy steel mounting sleeves, elevation pivots and strong backs that allow them to endure hard weather conditions and support big solar panel arrays. These structures allow the tilt angle to change very easily and come with a good variability range of 15° to 60°.
- Multi-pole Mounts
These structures are based on the same principle as the pole-mounted systems. The only difference is that all solar panels are laid in a single horizontal line (instead of being separated). This means that the solar system can be horizontally extended as much as is desired with additional vertical pipe supports.
The advantage that multi-pole mounts have over other solar ground mounting systems is that these structures allow the installation of bigger systems with great and simpler tilt variability, needing only one adjustment for all the panels, unlike pole-mounted which require an adjustment for each set of panels, and do not require as many soil perforations as other traditional systems. These systems are also ideal for carports or for shading purposes
Roof Mounted Solar Systems
Roof-mounted solar panels are the most common selection for households. Reasons for this vary, but the main one is the cost. Generally, roof-mounted systems are less expensive than ground-mounted systems, because the main structure needed to sustain the panels is the rooftop itself. This saves costs that would otherwise increase due to the aluminium or steel structures needed to support the ground-mounted panels.
Solar Panel Installation Suitable for a Sloped Roof
Most houses have a sloped roof design. Therefore, the solar mounting structure needs to adjust solar panels to an inclined surface. In order to do so, manufacturers offer several options:
- Rail Mounting System
This is the most common roof-mounted structure of all. Consists of attaching a set of rails to the rooftop. Each solar panel is then attached to the rails through a set of clamps. The rails are secured to the rooftop by screws and bolts.
- Shared-Rail Mounting System
This type of mounting system works the same as the railed system. The difference lies in the number of rails needed to be installed. While railed systems for a two-solar-panel row use four rails in total, shared-rail systems use only three rails—by using two rails on the edges and one in the middle that shares the two rows. Solar panel installation costs and time are reduced by using this technique, as one or two rails are no longer needed and neither are mid- and end-clamps. This system also implies fewer perforations to your roof.
Flat roofs are often found on commercial or utility buildings. But there are also many households with flat roofs that require a different approach than sloped roofs. The main mounting system used on flat roofs is known as the Flat Roof Ballasted Racking System. This system consists of a previously assembled structure with a set of ballasted blocks that go to the bottom and act as the support for the system which attaches the panels and the mounting system by the use of clamps and clips. Among the greatest advantages of this mounting type of system is the fast and easy installation. There is no need (or if, very few) for perforations to be made on the roof. It also offers some grade of flexibility to adjust the tilt typically between 5° and 15°.