By engineering the tilt of the panel to match the latitude of the building location, systems can generate an optimal amount of energy throughout the year.As solar technologies continue to evolve, new techniques and development of methodologies for implementing solar installations occur to make the process virtually seamless. This leads to more and more companies from all over the world to continue to look to this renewable energy source as a low-risk, high-return investment. As this demand continues to grow, so does the demand for greater efficiency and effectiveness of the system as a whole. In return, the answer to these demands is higher efficiency and lower cost solar technologies, and better strategies for space planning, building integration, and component utilization.
When people think about solar, they think about solar panels. Along with the inverter, the solar panels are one of the most critical elements of any solar array – and certainly the most popular.
At this point, new developments in photovoltaic (PV) technology happen almost every week. Regardless of a building’s unique needs, there is a PV technology that can support the installation and deliver the required energy-savings. That said, one must gauge what the needs are in order to determine where to start so that the installation will be as efficient as possible.
Before a company can even begin to look at installing solar panels, they have to look at the solar radiation data for the location. The National Renewable Energy Laboratories (NREL) has a great set of tools and models freely available to use as a reference source when determining a specific location’s solar return versus other renewable energy sources. In the end, determining if solar is a cost-effective method for generating energy will come down to economics.
While solar can be installed at any location, it is just not a cost-effective energy solution for some areas or situations. Once it is known how much potential solar energy can generated, how much on average the current cost of electricity is, and what kind of incentives (government or private) can be obtained for the project, those numbers can be compared to determine if a solar installation is the right fit for the building.
To determine the incentives, it might be beneficial to consult an industry expert. Some renewable energy solutions providers will provide you with information regarding local, state, federal, and utility incentives that may qualify for the installation. Having the system designer help with the incentives is generally a more fruitful strategy because incentives are dynamic and new incentives are being offered all the time.
When people think about solar, they think about solar panels. Along with the inverter, the solar panels are one of the most critical elements of any solar array – and certainly the most popular.
At this point, new developments in photovoltaic (PV) technology happen almost every week. Regardless of a building’s unique needs, there is a PV technology that can support the installation and deliver the required energy-savings. That said, one must gauge what the needs are in order to determine where to start so that the installation will be as efficient as possible.
Before a company can even begin to look at installing solar panels, they have to look at the solar radiation data for the location. The National Renewable Energy Laboratories (NREL) has a great set of tools and models freely available to use as a reference source when determining a specific location’s solar return versus other renewable energy sources. In the end, determining if solar is a cost-effective method for generating energy will come down to economics.
While solar can be installed at any location, it is just not a cost-effective energy solution for some areas or situations. Once it is known how much potential solar energy can generated, how much on average the current cost of electricity is, and what kind of incentives (government or private) can be obtained for the project, those numbers can be compared to determine if a solar installation is the right fit for the building.
To determine the incentives, it might be beneficial to consult an industry expert. Some renewable energy solutions providers will provide you with information regarding local, state, federal, and utility incentives that may qualify for the installation. Having the system designer help with the incentives is generally a more fruitful strategy because incentives are dynamic and new incentives are being offered all the time.
Structure, EnvironmentOnce it is been determined that a solar installation will be a valuable asset to the building, one must examine the layout and structural capabilities of the building. This will dictate the type of solar panels used and how they will be mounted. For example, typically on a rooftop installation, real estate is at a premium and traditional mono or multi crystalline panels will need to be selected as they offer the highest efficiency and energy production per square foot.
However, if it is a large roof, with a lot of unobstructed real estate, thin film panels or membranes, which are cheaper, but less efficient, may be a viable alternative.
The permanency of the array is a key determining factor. For example, one of the more popular installation options is a ballasted mounting system, which is a non-penetrating mounting system. Instead of bolting the system down into the roof structure, the installer simply places the system on top of the roof, using ballasts to hold the installation in place. This installation method is becoming increasingly attractive for building managers and owners due to the fact that it does not penetrate the roof membrane and can be removed or updated without any structural impacts. While a ballasted mounting system offers greater flexibility, attention must be paid to the structural integrity of the roof framing to ensure that the roof members can safely sustain the weight of the ballasted system. Solar providers use structural engineers to determine that the system layout and weighting are specifically designed to a meet a particular roof’s structure’s capabilities under the worst-case loading conditions.
Engineering of modern solar panels are to withstand most environmental conditions. Testing of panel is for the ability of the panel to withstand lead weighted balls dropped directly on their surface without causing any damage. This test requirement ensures that manufacturers’ panels can withstand most hail and flying debris.
Wind load is another environmental factor that needs consideration. When there is a flat rectangle with such a large surface area, it is bound to pick up some wind turbulence. Most cities have implemented some kind of wind load requirements that the installer will have to ensure the system can withstand.
For AEG’s solar installation at its North American headquarters in Plano, TX, the city designated the installation had to be able to withstand the same wind loads (90mph) as the roof structure. Since the installation utilized a ballasted mounting system, special precautions had to be taken to apply enough weight to each mounting bracket to ensure the system could hold up to the design wind conditions. Of course, the more weight you apply to the system, the more stress you place on the roof. In addition, it is important to tilt the panels to ensure optimal energy generation; however, when using a ballasted mounting system the degree of the tilt might be limited depending on the location and the wind requirements.
Typically, installers select an engineered mounting system that considers the tilt and size of the solar panel in use. By engineering the tilt of the panel to match the latitude of the building location, generation of an optimal amount of energy throughout the year is possible. For instance, in the AEG project mentioned earlier, Plano sits at roughly 33° latitude. To achieve optimal results, it would have been necessary to tilt the panels to a 33° angle. However, due to the design wind load of 90mph, and the fact that the array used a ballasted mounting system to reduce the structural impact on the building, the roof framing and required ballast weight only allowed the panels to be tilted at 15°. Even with this limitation, by proper tilting of the panel, there was significant increase in the energy yield.
Even after calculation of the mounting configuration and optimal tilt, one must still draw up plans for the placement. Commercial buildings require a lot more care and precision regarding rooftop array placement due to the extensive amount of equipment already on the roof. Air conditioning units, skylights, turbines, and other miscellaneous equipment not only create hurdles but also can cast shadows over larger portions of the roof that can limit the efficiency and effectiveness of the system. The system designers will need to assess the existing equipment on the roof and check the shadows created when determining the panel layout to ensure the system will continue to generate energy without losses.
Component ChoicesAnother key consideration when designing a solar energy system is the inverter. The inverter is the brain of the solar system, responsible for controlling the electricity flow between the panels, loads, and power grid. Inverters convert the electricity generated by the solar panels from a direct current (DC) into an alternating current (AC) that can then be fed directly into the building’s power source or into the power grid. Selection of the correct solar panel configuration to fit, electrically, with the inverter is critical. Each solar panel will have a standard test condition (STC) rating. This is the amount of energy the panel is expected to generate under optimal conditions. However, remember, the actual amount of energy the panel produces changes all the time due to varying weather states.
To accommodate the inverters, solar panels are connected to the inverters in string configurations. A single inverter may serve parallel input of several strings and the amount of strings per inverter is dependent on the inverter’s load capabilities. In the case of the installation at AEG, the array ended up using 234 solar panels, each with a 210W STC rating. The six inverters that were used on the building can produce 7,000W each; therefore, it was determined that AEG could accommodate three strings of 13 panels per each inverter, or 49.14kW STC total array rating.
In addition to providing the DC/AC conversion between the panels and the building, inverters are responsible for additional functions such as maximizing the power output, charging the battery (if you plan on using one), and protecting the circuit from potential damage due to failures or complications in the system. The inverter has a direct impact on the efficiency and effectiveness of the system as a whole. Since the inverter is directly responsible for providing the power generated by the solar panels to the building or grid, its overall efficiency is key to maximizing your investment. The lower the efficiency of the inverter, the more energy lost. Ideally, one wants to look for an inverter that offers 95% efficiency or greater. There are even some inverters capable of offering efficiencies greater than 98%. While these may cost a little more, if looking at a solar installation as a long-term investment, it may be worth considering the upgrade in order to maximize the system’s efficiency and overall ROI.
Finally, new technologies are helping to distinguish some inverters from the rest of the pack. While the solar system investment might be largely covered by government and utilities incentives, one still wants to see what kind of energy and returns can be achieved. Some solar inverters are being outfitted with new communications capabilities so that they can actually provide performance data, energy production information, environmental conditions, and faults or alarms in the system. While some of the data may not be important for the organization as a whole, it is critical for the person in charge of the system. They can choose to receive email alerts when an alarm goes off or there is a fault in one of the solar panel strings. This is especially important because solar installations, for the most part, are self sustainable. Once the initial installation is complete the system pretty much runs itself; however, if something does go wrong, or there is a problem, the need to react fast is important because every hour the system is not running at full speed is an hour of lost energy and money. For the most part, communications can be integrated easily into the existing local area network (LAN) to eliminate any additional costs.
Planning is CrucialWhen installing a solar energy system, planning is a crucial part of the component selection process. It is more about determining what your specific needs are and what tools will meet those needs most efficiently rather than just saying this is the best inverter or solar panel out there and everyone should be using it. There are so many external factors involved in the process that can have a major impact on the efficiency and effectiveness (from both a production and a cost perspective) on the system as a whole. When it comes down to it, those are the two most important characteristics of any solar installation – efficiency and effectiveness. It is the main reason people turn to solar in the first place: They are looking for a way to meet their energy needs that is more efficient and effective than traditional means.
AEG Power Solutions
Plano, TX
Plano, TX
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