Do concrete roofs and metal roofs have different mounting structure?

Solar PV modules can be installed on almost all kinds of rooftops. The complexities involved in installing a PV module may differ with different rooftops, type of roof construction and roof strength. Therefore there are different PV module mounting structures for metal roofs and flat concrete roofs. Some of the examples of commonly used mounting structures based on the roof type are mentioned below. Flat concrete roofs (example RCC) Concrete roofs are in general the easiest way to install a solar power plant as the access for installation and later operations and maintenance if very easy. Depending on the roof design and shadow-free area the common type of module mounting structures for concrete roofs are highlighted below: 1. Low elevation ballast structures  This type of structures are designed for flat roofs with limited load capacity and where there are no shadow issues. The design of the system includes a windshield (sloped wind deflector) that seals the system and reduces the suction force of the wind on the PV modules making the installation stable under high wind load and prevents the frame from overturning/lifting. Typically such mounting structures have a tilt angle of not more than 15 degrees. 2. Elevated ballast structure This type of structures are advised for flat RCC roofs which have shading issues. These structures can be designed for high ground clearance and can easily combat heavy wind loads. These structures are also designed for installation with penetration to the roof; however, it is not recommended. Instead ballast-based […] Read more

Can a mounting structure cause damage to my roof?

Many property owners worry about damaging their roof on installing a rooftop solar PV power plant. However, as these installations will last at least for 25 years, so it is important to make sure that all pre-existing damage to the roof is assessed and repaired, if needed. It is also to be noted that the installation being done should be well within the safety limits and it should be able to withstand the weight of an additional structure without any structural damage, leakage and water logging, etc. PV module mounting structures designed and installed correctly do not cause damage to the roof. The spacing of brackets and purlins spreads the weight of the solar panels across a large cross-section of the roof area. If you have a flat roof, you won’t need to put holes in it for installation. Installations on flat roofs commonly use ballast mounting systems which involve no holes. A few examples of ballast mounting structures used widely these days are: Roof damage as a result of a solar PV power plant installation is extremely rare because installers take precautionary steps while installing the structure and the solar panels. However, if property owners are concerned about damage to the roof, they can question the installer about their installation process, measures they take to prevent roof damage and workmanship warranty, and check whether it covers the roof damage in case it occurs. Like this:Like Loading... Read more

What are the components of a Solar PV Module?

Solar photovoltaics are made with a number of parts, the most important of which are the solar cells which are connected and sandwiched between glass and metal. Major components of a PV module are: Module Frame   Glass Encapsulant Back Sheet Backsheet is a film of that protects the solar cells from severe environmental conditions. A solar back sheet is the last layer at the bottom of the solar PV module and is typically made of a polymer or a combination of polymers. Junction Box                         Like this:Like Loading... Read more

Difference between mono-crystalline and poly-crystalline PV modules

Both mono-crystalline and poly-crystalline solar PV modules have cells made of silicon wafers. To build a mono-crystalline or poly-crystalline module, wafers are assembled into rows and columns covered with a glass sheet, and framed together. Poly-crystalline cells are square-shaped whereas mono-crystalline cells are square with missing corners. While both of these types of solar PV modules have cells made from silicon, mono-crystalline and poly-crystalline modules vary in the composition of the silicon itself. Mono-crystalline solar cells are cut from a single, pure crystal of silicon. Alternatively, poly-crystalline solar cells are composed of fragments of silicon crystals that are melted together in a mold before being cut into wafers. Mono-crystalline modules have better efficiency and power capacity. Like this:Like Loading... Read more

How does temperature affect solar panels?

Solar panels react differently to the operating temperature. The efficiency of a solar panel decreases as it increases above the ambient temperature. Each solar panel has a temperature coefficient (which is defined in datasheet of panels). The temperature coefficient represents the rate at which the panel will underperform at each increase in degree Celsius (°C). Most panels have a temperature coefficient of between -0.2% /°C to -0.5%/°C, when tested under standard laboratory conditions, where ambient temperature is set to 25°C. For example if the temperature coefficient of a particular type of panel is -0.5%, then for every 10C rise, the panel’s output power will reduce by 0.5%. [Source: Youtube] [Publisher: altE Store’s Educational Video Channel] Like this:Like Loading... Read more

Cables used in a solar rooftop system

The cables used in a solar PV system transport the electricity generated from the system to the load. The cables used in the system used can be classified as Alternating Current (AC) or Direct Current (DC) cables. The DC cables carry the power from the PV modules to inverters, whereas the AC cables carry the AC power from the inverter to the metering point. DC Cables: Solar DC cables interconnect solar panels to the combiner boxes to an inverter. The DC cables are usually two-core cables, a current-carrying live wire, and a negative wire, both are typically surrounded by an insulation layer. DC cables are generally made of copper conductors which provides more flexibility. As the life of the solar plant is expected to be more than 25 years, DC cables should be capable to withstand high temperatures, UV radiations, fire risk, exposure to water, etc. There are two types of solar DC cables: Module cables: These cables are usually integrated into the PV solar panels and are equipped with suitable to be interconnected. fig: Module DC Cables     Main cables: The extension cables used to connect the module strings to the DC combiner boxes or the inverter. AC Cables: The AC cables connect the inverter to the load via protection devices. In the case of three-phase inverters, the connection to the low voltage grid is made using five-core AC cables (three live wires for the three phases that carry the current, a neutral wire carry current away from the device and ground wire […] Read more

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