How it Works Why is it Beneficial?
An average household uses 800 kW-hr of electricity per month. If solar power delivered half of that for 28 years it would prevent the production of:
1/2 a ton of SO2
1/3 a ton of NO2
100 tons of CO2

A properly installed and maintained system not only saves you money and gives you energy independence, but is environmentally friendly, too. Solar power panels, or modules, are what most people think of when they think of a solar power system, although they are in fact just one cog in the system. This guide is a short introduction each component in the system and to help give you a full picture to how the system works to provide clean cheap energy for your home.

Efficiency
The "photovoltaic effect" is a straightforward process by which solar cells convert sunlight into usable electricity. The earliest solar cells converted only 1-2% of the sun's light energy into usable electric energy, whereas today's units can convert some 15-20% of sunlight's energy. Increasing panel efficiency allows for smaller, cheaper systems, which in turn allows for greater accessibility for varying income brackets as well as physical applications.

The solar power modules (solar panels and other types). A solar power module, often called a "solar panel", is essentially an array of many individual solar cells; a module will produce from 50 to 480 watts.

A key component in your solar system device chain is the inverter. Inverters modify the solar energy modules' current and voltage to maximize output, and convert their DC power to the AC power required by most of business and home equipment. Inverters are rated and compared to one another based on their capacity, their voltage rating and their battery capabilities. Often they are installed along with fuse boxes, switches and other electrical components in a "control center" that relies on certified electrical service boxes. Inverters should typically be mounted in dust-free, dry and well-ventilated areas.

Racks, mounts and roof attachments for solar systems To withstand years of exposure (wind, weather, corrosion, etc.) the solar array has to be solidly mounted. It may appear from street level that solar panels are directly atop a house's roof, but this is not the case. Mounting on roofs has to take into account the roofing materials, their condition, their future replacement needs and so on. A professional solar installer knows the ins and outs of all mounting alternatives, and you are strongly advised not to jeopardize your home's roof by going up yourself to nail down some panels.

Wiring and meters
For long-term stability and efficient operation, there is probably no more important component than the one you probably will see least, the wiring. You will have to follow construction codes as well as the National Electrical Code, and use devices that carry a rating agency certification, as from Underwriters Laboratory. At EcoSun we stay current with all the codes and regulations.

Connections can become loose over time from ongoing "rooftop heat cycling," and this is a common cause of poor system performance, it's always a good idea to have a plan in place should your system ever experience an issue.

Monitoring Systems
To monitor system performance, it may be useful to install a separate solar power electric meter. EcoSun carries several different monitoring systems to custom tailor the needs of the customer. Monitoring systems will give you real time performance evaluations and a historic review of usage enabling the customer to verify the performance of his or her system. Monitoring can spot trouble issues and help isolate the problems if any arise.

A solar system is a chain of devices that takes power from once source (the sun) and makes it usable in your home. You can think of it as even a kind of organism, taking in fuel and converting it to practical use by way of light bulbs, radios, toasters and other appliances. All of the pieces of you solar power system need to work together, and when they do you are able to reduce your energy costs, help the environment and make a serious contribution to a realistic, sustainable future.

How Photovoltaic (PV) cells work

PV cells are made up of at least 2 Semi-conductor layers. One layer containing a positive charge, the other a negative charge.

Sunlight consists of little particles of solar energy called photons. As a PV cell is exposed to this sunlight, many of the photons are reflected, pass right through, or absorbed by the solar cell.

When enough photons are absorbed by the negative layer of the photovoltaic cell, electrons are freed from the negative semiconductor material. By way of the manufacturing process of the positive layer, these freed electrons naturally migrate to the positive layer creating a voltage differential, similar to a battery.

When the two layers are connected to an external load, the electrons flow through the circuit creating electricity. Each individual solar energy cell produces only 1-2 watts. To increase power output, cells are combined in a weather-proof package called a solar module. These modules (from one to several thousand) are then wired up in serial and/or parallel with one another, into what's called a solar array, to create the desired voltage and amperage output required by the given project.

Photovoltaic cells are generally made from modified silicon, or other semi conductive materials, that absorb and convert sunlight into electricity. Photovoltaic cells are long lasting (the first PV system ever installed in the USA – in 1954 – is still operating today).

Due to the natural abundance of silicon, the semi-conductor material that PV cells are primarily made of, and the practically unlimited resource in the sun, solar power cells are very environmentally friendly. They burn no fuel and have absolutely no moving parts which makes them virtually maintenance free, clean, and silent.

Source: eZine Artciles

Types of solar cells
There are three basic types of PV solar cells
Monocrystalline
Polycrystalline
Thin Film

Monocrystalline cells are cut from a silicon ingot grown from a single large crystal of silicon. These cells yield the highest efficiencies.

Polycrystalline cells are cut from and ingot made up of many smaller crystals. Although the efficiency is slightly higher in monocrystalline, there is little practical difference in performance.

Thin Film or amorphous. This technology is more often seen in small solar panels, such as those in calculators and yard lights, although thin film panels are increasingly used in larger applications. They are made by depositing a thin film of silicon on another sheet of material such as steel. The panel is formed as one piece and the individual cell are not visible as in the crystallines. The efficiency of the thin film panels are not as high as those made from individual solar cells. This has improved in recent years to the point where they can be seen as a practical alternative to panels made with crystalline cells. Their big advantage lies in their relatively low cost per Watt of power generated, however, by their low power density, more panels are needed for the same power output. Another advantage to thin film would be that they perform well in extreme heat or overcast sky’s.

In the southern Californian area, EcoSun solar prefers to use crystalline panels. They perform the best and do last considerably longer.

How inverters work
At EcoSun Solar we have found the one of the most incredible thing about solar photovoltaic power is its simplicity. Compared to other sources of energy man kind has harnessed to make electricity, PV is the most scalable and modular. Larger systems require more electrical bussing, fusing and wiring, but the most complex component that processes and converts electricity: the inverter.

So how can an inverter give us a high voltage alternating current from a low voltage direct current. Let's first consider how an alternator produces an alternating current. In its simplest form, an alternator would have a coil of wire with a rotating magnet close to it. As one pole of the magnet approaches the coil, a current will be produced in the coil. This current will grow to a maximum as the magnet passes close to the coil, dying down as the magnetic pole moves further away. However when the opposite pole of the magnet approaches the coil, the current induced in the coil will flow in the opposite direction. As this process is repeated by the continual rotation of the magnet, an alternating current is produced. Now let’s consider what a transformer does. A transformer also causes an electric current to be induced in a coil, but this time, the changing magnetic field is produced by another coil having an alternating current flowing through it. Any coil with an electric current flowing through it will act like a magnet and produce a magnetic field. If the direction of the current changes then the polarity of the field changes.

Now, the handy thing about a transformer is that, the voltage produced in the secondary coil is not necessarily the same as that applied to the primary coil. If the secondary coil is twice the size (has twice the number of turns) of the primary coil, the secondary voltage will be twice that of the voltage applied to the primary coil. We can effectively produce whatever voltage we want by varying the size of the coils.

If we connected a direct current from a battery to the primary coil it would not induce a current in the secondary as the magnetic field would not be changing. However, if we can make that direct current effectively change direction repeatedly, then we have a very basic inverter. This inverter would produce a square wave output as the current would be changing direction suddenly. This type of inverter might have been used in early car radios that needed to take 12 volts available in the car and produce the higher voltages required to run radio valves (known as tubes in America) in the days before transistors were widely used. A more sophisticated inverter would use transistors to switch the current. The switching transistors are likely to be switching a small current which is then amplified by further transistor circuitry. This will still be a square wave inverter.

The Sine Wave Inverter
To get a sinusoidal alternating current from the output of our transformer, we have to apply a sinusoidal current to the input. For this we need an oscillator.

An amplifying transistor can be made to oscillate by feeding some of the amplified output back to its input as positive feedback. We will all have heard this effect at sometime when someone is setting up a PA or microphone system. If the microphone is too close to the speaker, some of the output from the speaker is fed back to the microphone and inputted to the amplifier again. The result is a howling sound.

The positive feedback in an electronic circuit can be tuned using extra components to produce the frequency we require (generally either 50 or 60 cycles per second to mimic mains electricity). If a crystal is used to control this frequency, as in a battery watch or clock, the frequency can be very accurately controlled.

As with simpler switching transistor circuit, the oscillator will be producing a low current output. This will then need to be amplified by what will be roughly equivalent to a powerful audio amplifier to produce the high current for the primary coil of the transformer (the frequency of mains AC current is roughly equivalent to the lowest notes on a bass guitar).

The transformer, while being very useful, does not do something for nothing. While increasing the voltage, the current will be reduced, and the power (voltage x current) will stay the same (less any inefficiency of the transformer). In other words, to get 1Kw of high voltage AC current out, you have put 1Kw of low voltage AC current in.

Grid Tied Inverters
If the above example were a grid tied inverter, ie able to feed power back into the national grid, it would need to use a sample of the mains voltage to then be amplified within the inverter, or to synchronize the oscillator with that sample.

Grid tied inverters will also sense if there is a "power cut" and disconnect themselves from the grid. If they did not have this facility, in the event of a power cut, your inverter would be attempting to power all your neighbors houses and would present an electrocution risk to anyone working on power lines that had supposedly been turned off.

Maximize your solar power savings.
By now you should have a thorough understanding of how solar works. You have done extensive research, crunched all the numbers and finally decided to move forward with plans to install a solar system for your home or business. EcoSun can walk you through the process of sizing your system. But before we do, we need to address some important factors that can save you hundreds or thousands of dollars by solar prepping your home or business with some simple steps that can make it more energy efficient, and thus reduce the size and cost of your solar system.. Below are some basic ways to save more money by downsizing the system needed.

Energy efficient windows and drapes
Most homes and not just older ones tend to breathe a lot. The windows and doors don not shut tightly and have poor insulating characteristics. Modern windows especially dual paned, are much better than single pane. There is also a window film out now that can reduce up to 75% of radiant heat coming through by direct sunlight. Old or new you should periodically check for cracks and leakage around window perimeters. Drapes do wonders for containing hot and cold air as well.

Door Seals
Along with windows, doors are one of the main ways that air travels in and out of your home. We do have to open and close them for access, but there are plenty of low to no cost ways to keep them from breathing so much. Any hardware store will carry doors seals for very little cost. Bottom seals and side seals are very easy to install. Place your hand near the door, if you feel a breeze, a new seal may be in order.

HVAC System
The granddaddy of all energy hogs. Although, it does not have to be. Whatever kind of heating, ventilation and/or air-conditioning (HVAC) system you have, check for leakage of any kind, Check filters, as clogged or dirty ones can dramatically reduce efficiency, and ducts to ensure that there are no leaks. How old is your air-conditioner? If it is more than 8 years old, a new on may be in order. A new high efficient HVAC can reduce your demand up to 50%.

Attic Fans and Whole house Fans
I take particular interest in this one as it has reduced my HVAC usage by 50%. The new breed of whole house fans (WHF) are quite as a refrigerator. There are two basic types out there. One is a large unit for the whole house and the other is a ducted unit that goes to each room.. The good ones are a two speed system. The idea behind whole house fans is to cool the house, not just the temperature of the air. I mean cool the structure, walls, wood, and attic. When the evening air outside cools down, you turn the fan on high for 15 min.. Then turn the fan on low for the next 2 to 3 hours and you will cooled the entire home, and, not have a need to run your HVAC at night. Without a WHF and attic will only cool down by 15-20 deg. A hot attic can keep your HVAC running all night. The next big saver is an attic fan, although they can help keep and attic ventilated, they still use electricity. The good news is, EcoSun carries solar powered attic fans. These are amazing little units that deliver. Keeping the attic ventilated is one of the best things you can do to keep your HVAC from running. It won’t stop it, but can reduce daytime usage up to 30%. This means savings. Coupled with a whole house fan system, you keep your HVAC from working so hard. Rebates are offered on these items as well. Call your EcoSun representative today to find out about the fan products we carry.

Lighting
Lighting can do more than one would think. Our customers can testify of a savings up to 15% just by changing their light bulbs over to compact fluorescent lights. (CFL).By going even further and changing to Light Emitting Diode, (LED), they get and additional 10%. CFL’S are not as costly as LED’S and offer a better life span than traditional incandescent. A typical 13 watt CFL is equivalent to a 60 watt incandescent. And a 7 watt LED is equivalent to the same 60 watt incandescent. LED’S are a bit more costly but significantly outlast a CFL or incandescent. LED lighting has come a long way. Fluorescent fixtures with T-8 lights can now be retrofitted with LED tubes. A typical 32 watt T-8 can be replaced with a LED 15 watt tube and eliminate the need for ballasts and ballast replacements. EcoSun is your solution to lighting.

Be energy conscious
Being an energy conscientious citizen takes effort. Green bumper stickers and Energy Star appliances are great ideas, it still takes a strong cooperative effort all over the globe and it starts with you. It all depends on your effort to develop an energy-conscious lifestyle to ease your financial burdens as well the planets environmental ones. Preparing your home or business means preparing yourself first.

As you can see, preparing to install a solar power system means much more than analyzing your electric bills, estimating square footage of sunlit roof tops or figuring out your rebate plan. When you take steps toward installing your EcoSun solar power system, these simple steps will keep your energy-use estimates low, and help save thousands on a system that is sized properly for your home. Reducing your energy consumption will save you money and relieve energy demand on the planet. Contact your Ecosun Solar representative today and ask for our comprehensive energy audit.