Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics(PV), indirectly using concentrated solar power, or a combination. Concentrated solar power systems...
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Solar photovoltaic modules, often referred to as solar panels, convert light energy into a direct electrical current (DC). As solid-state devices, solar modules have no moving parts and are extremely reliable and durable compared to any other generator technology. While solar modules have become somewhat commoditized in recent years, there are important differences in form, quality, and performance that can impact both installation time and long-term system performance. We offer a selection of high-quality crystalline modules with a variety of features and price points to suit virtually any project.
The output power, voltage, and current profile of the solar module will dictate the number of modules needed and what inverters or charge controllers can be used. Small off-grid applications often require 12 VDC output modules to directly charge batteries and/ or operate DC loads. Larger modules with output voltages ranging from 24 to 50 VDC are more commonly used in grid-tie systems where a high DC voltage is required to operate the inverter.
Basic mechanical characteristics, such as dimensions, frame profile, and static load rating, as well as grounding and mounting locations will need to be understood when designing your system. Frame and back sheet color may also come into play for residential customers, particularly when they are part of a homeowner’s association. Also be sure you know what type of connector the module output has, if any, since this can impact selection of optimizers, micro-inverters, and cabling.
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Generate your own electricity with solar energy panels to save energy and earn money back
Solar panel electricity systems — also known as solar pv panels or photovoltaic panels — capture the sun’s energy using photovoltaic cells and convert it into electricity for you home. Photovoltaic panels have been in use for decades and represent an environmentally-friendly means of converting solar energy into electricty. These cells don’t always need direct sunlight to work, and can still generate electricity on cloudy days.
Learn about solar panels. Solar panels are a common solution and have a lot of advantages. They work in most of the world, are a modular solution which can be expanded to suit your needs, and there are many well-tested products available.
- In general, panels should have south facing direct exposure to the sun (north-facing in southern hemisphere, up-facing near equator). The angle measured from a spirit level should be your latitude (You can look that up in Google maps.) In overcast conditions you will only get a fraction (10-15%) of electricity as to sunshine.
- Fixed mounts can be built onto their own structure (which may house batteries and charge controller beneath) or placed on an existing roof. They are easy to mount and to maintain if near the ground, and have no moving parts. Tracking mounts follow the sun and add efficiency(+50%) and longer battery life. These are mechanical contraptions that have a risk being damaged by high winds and have moving parts to eventually wear out. Since the early 2010s it can by less expensive simply adding a couple more panels to east and west to get the same harvest.
- Just because a solar panel is rated at 100 watts doesn’t mean it will deliver that much on a regular basis, on contrary, higher temperature and any angle the sun not being 90 degrees over the panels will conspire to give less electricity (calculate with 70% of rated performance to be safe)
Decide on your system type. If you have the choice, consider whether you want a stand-alone power solution or a grid-connected system. A stand alone power system is the ultimate in sustainability; you will know the source of every watt you use. A grid-connected solution gives you stability and redundancy, and can also provide an opportunity to sell power back to the utility company. If you are grid-connected, but manage your power usage as if you were stand-alone, you can even generate a little extra income, but be aware of political risks of cuts to these subsidies.
- Contact your current utility provider and ask them about grid-connected systems. They may be able to provide incentives and will be able to tell you who to hire to set up your sustainable power supply.
Using Alternative Systems
Learn about wind turbines. These are solutions in many locations especially in very overcast and windy climates. There it can be more cost-effective than solar power.
- You can use a DIY wind turbine made from an old car alternator, with plans available on the net. This is not recommended for beginners but can achieve suitable results. There are also fairly inexpensive commercial solutions. One option, a ghost wind turbine, is made of clear plastic which makes it less conspicuous.
- There are some drawbacks to wind power as well. You may need to put turbines very high in the air for them to work effectively, and your neighbors may see them as an eyesore. Birds may not see them at all…until it’s too late (just joking).
- Wind power needs fairly consistent wind. Open, desolate areas work best as they have the fewest things blocking the wind. Wind power is often used effectively to supplement a solar or hydro system.
2Understand micro-hydro generators. There are various types of micro-hydro technologies available, ranging from a homemade propeller connected to a car alternator to fairly robust and intricately engineered systems. If you are on a riverfront property, this could be an efficient and self-contained solution.
Consider a fossil fuel (petrol/diesel/gas) generator. If there is no grid, or you want disaster/blackout backup or you run workshop machinery, a generator may be required.
- Many generators are very slow to react to load changes,which make them unusable for washing machines (switching on a power-hungry device an cause the power to falter).
- Small, commonly available generators at your hardware store are made for occasional emergency use. They will quickly fail if used for daily power.
- Large household generators cost a significant amount of money. They can run off gasoline, diesel or LPG, and usually have a self-starting mode where they kick on when the grid power is interrupted. If installing one, make sure you work with a licensed electrician and follow all building codes or be very smart.
- Generators made for RV, trailer, or marine use are small, quiet, made for continuous duty, and are much more affordable. They can run off gasoline, diesel or LPG, and are made to run on demand for hours at a time for a period of years.
- Cogeneration or Combined Heat and Power systems (CHP) produce power and heat simultaneously. This is only good for you if you have use for that heat, even in summer.
- Many generators are very slow to react to load changes,which make them unusable for washing machines (switching on a power-hungry device an cause the power to falter).
Getting the Right Stuff
5Get qualified help. Not every contractor or handyman is equally qualified to install these systems. Only work with experienced vendors and installation specialists who are licensed to work with your given equipment. Working with an Unlicensed Contractor or Handyman could cost you if the worker happens to make a mistake while installing your system.
Preparing for the Worst
Think about your plan for backup power. The natural elements that a self contained power system use on are not reliable. The sun is not always shining, the wind is not always blowing, and the water is not always flowing.
- Using a grid-connected system is the least expensive solution for most people, especially those who are already power customers, but energy companies do pollute the planet considerably. If forced, they install one sort of power (such as solar), and tie the package to the grid. When there isn’t enough power coming in, the grid makes up the shortfalls, and when there is excess power, the grid buys it. Oversized systems can consistently run the power meter backwards.
- If there is no power service nearby, it can be much more expensive to get connected to the grid (or even to connect an outbuilding to the house) than to make and store your own power, this is even more true from the mid 2010s on.
Using and Choosing Batteries
2Calculate how many batteries you’ll need. Storage capacity is rated in amp-hours. If you want roughly kilowatt hours multiply amp hours times the number of volts (12 or 24 volts), and divide by 1000. To get amp-hours from kilowatt-hours, just multiply by 1000 and divide by 12. If your daily use is going to be 1KWH, you’ll need about 83 amp/hours of 12 volt storage, but then you need 5 times that (considering you never want to discharge past 20%), or about 400 amp-hours to deliver that amount of juice.
Choose your battery type. There are many different kinds of batteries and it is important for you to choose which is best for you. Understanding what will work is not easy. Find a company which can prove it has been running a battery stack for longer than 5 better 10 years. Guesswork or sales pitch will give poor results
- Wet cells are the most common. They need to be serviced (the tops come off so you can add distilled water), and they need an occasional ‘equalize’ charge to cook the sulfur off the plates and keep all of the cells in about the same condition. Some high quality wet cell batteries have independent 2.2 volt cells that can be replaced if they go bad. “Maintenance free” batteries will lose water as they gas off, and eventually cells will dry out.
- Gel batteries are not serviceable, and unforgiving of charging problems. A charger designed for a wet cell will cook the gel off of the plates and form gaps between the electrolyte and the plates. Once one cell has managed to overcharge (due to uneven wear), the whole battery is bad. As part of a small solution, they work reasonably well, but don’t work well in larger solutions.
- Absorbed glass mat batteries are more expensive than either of the other types, and don’t need service. As long as they are charged correctly, and not cycled too deeply they will last a long time, and they can’t possibly leak or spill—even if you smash them with a hammer (though we’re not sure why you would want to do that).They do still give off gas if excessively overcharged.
- Car batteries are just that, for cars. Car batteries do not perform well in situations that call for deep cycle batteries.
- Marine batteries are usually hybrid deep-cycle and starting batteries. As a compromise they work well in a boat, but not well for household power.
4Have batteries even with a generator. Even with a generator, batteries are required in an off-grid system. Charging batteries will put a reasonable load on the generator so it works efficiently for the fuel it consumes, while simply running lights will put mostly light loads, which are very inefficiently handled by most generators.
Installation & Electrical Distribution Parts Power Panels
Power panels provide a central location for mounting inverters and charge controllers in battery systems and include enclosures for wiring, over-current protection, ground-fault and surge protection, bypasses and related hardware.
Fuses and Breakers
Fuses and breakers are designed to prevent excessive current from overheating conductors or devices by opening the circuit. Specialized breakers can also be deployed to open the circuit in case of arc-fault conditions. Fuses and breakers should be sized according to NEC and/or manufacturer guidelines to ensure that they open the circuit before conductors or equipment can become damaged.
Photovoltaic, wind, and hydroelectric systems usually have long runs of exposed wire that can pick up surges from lightning, even if the lightning strike is only nearby. These power surges can damage sensitive electronic components in meters, charge controllers, and inverters. Surges can also damage telephone, audio, and video equipment connected to the power system. It is a good idea to install surge protection on all incoming wires in the system, including incoming photovoltaic, wind, or hydroelectric power lines; AC generator lines; and telephone and antenna leads. Proper grounding is absolutely necessary for lightning protection to be effective. In the event of a direct strike, damage may occur, even with surge protectors installed. Type 1 heavy duty surge protectors are recommended when a direct lightning strike is possible on the installation.
Proper equipment grounding helps to ensure that any electrical faults that may develop in a PV system have minimal opportunities to cause fires or electrical shocks. It is just as important to be familiar with NEC 250’s general grounding requirements when installing PV as it is to know 690. Jurisdictions and inspectors may vary on the grounding equipment and techniques they consider acceptable, so it is also important to know what your inspector will be looking for.
SnapNrack, as well as some other mounting system brands, now offer UL 2703 listed racking packages that incorporate much of the equipment grounding by bonding modules and related gear to the rails. However, not all equipment is considered compatible or likely to be accepted by a particular inspector, so it’s important to have some other options like those offered here.
Array combiners are used to electrically combine the output of multiple series strings of PV modules into a single wire to simplify the connection to an inverter or charge controller. They typically include string-level overcurrent protection and sometimes host other functions such as monitoring, a disconnect, or even AFCI and remote shutdown. It is important that the combiner used be rated for the worst-case voltage and current the array can output.
Disconnect switches provide a means for safely opening a circuit between the power supply and any loads that may be present. Some disconnects also offer fusing, remotely-actuated contactors or other specialized functions. The NEC requires listed disconnects in a variety of situations. Be sure to choose a disconnect that is rated for the AC or DC voltage and current that may be present on the circuit.
Load centers provide a central location for mounting busses and breakers to feed multiple load circuits from a single power supply such as a utility service or inverter output. The NEC requires NRTL-listed load centers for most applications. Be sure to choose a load center that is rated for the AC or DC voltage and current supplied as well as any application-specific requirements.
Low-voltage power systems with inverters can have very high current through the cables that connect the inverter to the batteries. Large AC loads like microwave ovens, toasters, irons, and washers can cause an inverter operating on a 12 VDC battery system to draw over 100 A. Large motors may draw 300 to 500 A during startup. When cables between batteries, and from the battery bank to the inverter, are too small, the current available to the inverter is limited and it may fail to supply larger loads. Properly sized cables also impose less resistance and thereby help maximize system efficiency. Use this chart to find typical ampacity limits by wire size.
Array Cables and Connectors
Grid-tie modules generally ship with attached cables that are listed to UL 1703 with the module. The cable connectors on these are fully waterproof when connected, touch-protected and designed for up to 1,000 VDC and 30 A, but cannot be safely disconnected under load.
Our output cables are made with 10 AWG PV Wire and Amphenol H4 connectors, and can be used in solar arrays up to 1,000 VDC. All of our array output cables are made with PV wire that is listed to UL 854, which is required by the NEC for use with transformerless inverters.
Additionally, we stock the common styles of crimp-on connectors for use with 10 AWG PV stranded wire. Proper crimping to the wire and insulator assembly requires special tools.
Wire Management Hardware
As most experienced PV installers will attest, good wire management is a hallmark of high-quality installations, and its lack can lead to inspectors and customers alike looking for other potential issues. Cables and wires should be kept off the roof or ground and water should not be allowed to pool at the entrances of enclosures, splices and junction boxes. Given that a solar PV system is designed to last for 25 years or more, it is vital to use wire management hardware that will hold up in the environment and allow deployment with minimal strain on the components.
PV Cable Assembly Tools
Crimp-on PV cable connectors require special tools to properly attach the connectors. Single-purpose tools from Multi-Contact or Amphenol work with only that type of connector and are often the best option for installers who work only with modules that have that same connector type. For those who encounter several different types of connectors, one of the Rennsteig tool sets that have sets of dies and positioners can be more convenient and economical than carrying a different tool for each connector type.
System Survey and Commissioning Tools
Surveying and commissioning a PV system are important steps in the installation process, and it’s worth doing properly and consistently. Commissioning standards, such as IEC 62446 and related NABCEP guidelines, provide visual and physical inspections as well as electrical tests that should be performed prior to activating a new PV system. Common electrical tests made during commissioning include: continuity, phasing, and voltage for AC circuits; continuity of grounding conductors; DC circuit polarity verification; string I-V curves; string open-circuit voltage; string short circuit current; insulation resistance testing of PV source and output circuits; and, finally, a full-up system functionality test. With proper documentation, these same tests can be repeated periodically as systems age to ensure that they are operating efficiently.
Solar Safety Labels
The NEC and International Fire Code (IFC) require specific components of a PV system to be labeled for the safety of operators, maintenance, and emergency responder personnel. The Code also requires these labels to be appropriately weather resistant (IFC 605.11.1.1.3) and durable (NEC 110.21). These labels are UV and weather resistant and should meet Code requirements in most jurisdictions. Note that some jurisdictions may still require engraved placards. The labels are designed to permanently adhere to metallic, baked enamel, and powder-coated surfaces in most outdoor environments.
Local jurisdictions and company policies often call for unique language or types of labels that are not available in preprinted form. If this is a frequent requirement, a label printing system can be an economical way to get exactly what you need when you need it. The ability to produce custom labels also presents opportunities for branding as well as organization, theft prevention, and identification.
Remember solar energy has been used by our ancestors in many ways. The glass lenses were used for creating fire by magnifying the sun rays. Even prior to that, the flint stones were used to create fire. Now the solar energy can be harnessed for creating electricity which could be stored and distributed in a pollution free atmosphere. Large investment is one of the primary reasons why solar energy is still not used by many people across the world.
What is Renewable Energy? All the energy we use comes from the earth. The electricity we use every day...
https://www.youtube.com/watch?v=3oN1nh-XWVo Have you ever used a magnifying glass to make something melt or burn? You were using solar power!...
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