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Jan 2014
Published January 31, 2014 | By admin

One of the comments we often hear from clients who have tried repairing their own electrical problems is “I thought it would be an easy fix”. As Santa Monica electricians, we understand our services don’t come cheap. We try to stay competitive while making sure you don’t feel cheated. That means we provide discounts and specials all the time, but sometimes that isn’t enough. Sometimes our clients try to fix their own problems and while we admire their proactive attitude, it often just makes the problem even worse; sometimes, people can get hurt. We had a client named Dan who caused an electrical short when he messed around with a live outlet. He was still cleaning up burnt tile when we got there. Don’t be Dan.

Oftentimes, our clients think the problem is a faulty outlet or a bulb that is at the end of its life. Oftentimes, our clients are wrong and much to their chagrin, it’s the wiring behind the wall that is to blame. These wires are a twisted mess sometimes and it’s best to call a professional electrician to take a look. We know how to navigate a bundle of live wires hidden in the spaces of your home without causing an electrical fire. If it’s a broke breaker, leave those to us.

Please never underestimate an electrical problem. Even a small chewed-down wire can lead to a rather large and destructive electrical fire. If you’re not absolutely certain you can fix it, give an electrician a call. We’re qualified, licensed, and insured. Rest assured, the problem will cease to be a problem with a professional on the job. Please don’t delay. Unless you plan on shutting off electricity and living in the dark, we insist on taking care of any electrical trouble as soon as you are made aware of them.

Posted in Blog

Jan 2014
Published January 30, 2014 | By admin

Have you ever visited a home with a path lit up by electric torches or shrubs and trees that were illuminated by a ground light? This is known as landscape lighting and it can make even the average home appear more than average. Many homeowners choose to border the walkway leading to the front door with lights, to make it easier to navigate in the night. Done well, landscape lighting can used to accentuate an outdoor space and create a visually interesting display as well as creating a welcoming atmosphere for guests and residents, alike. In addition to the aesthetic value of lighting arrangements, exterior lights help deter burglars and other intruders from attempting anything on your property.

The Santa Monica electricians at B.K. Electric Services have ample experience with creating an effective display of lighting and lighting accents, all under budget. And since we work during the day, you can watch as your lights stun you when the sun sets. Our in-house designers will work with you to compose a symphony of light. It sounds dramatic and cheesy, but you’ll thank us when your neighbors tell you how much they love your front yard. There is also a style of landscape lighting called moon lighting, in which lights are placed high up in trees to simulate the effect of moonlight breaking through the branches. The effect is enchanting and frankly, magical.

Your lights can be placed on timers so they can fade away when the sun rises and return when the sun sets and the moon is the only light you see. Your home will be well-lit in the nighttime, which has the unforeseen benefit of acting as a burglar deterrent. Who would rob a house that is so bright? Not anyone smart, that’s for sure. We can create strategic lighting to cast light onto dark corners or shrubs where animals or intruders could hide and creep. Have the electricians in Santa Monica convinced you yet? If you’re interested in landscape lighting, give B.K. Electric Services a call. You won’t regret it.

Posted in Blog

Jan 2014
Published January 24, 2014 | By admin

How many of you have ever tried to plug in something as simple as a cell phone charger and have ended up sticking your finger in the live outlet? It hurt, did it not? There is that jarring tremble of your arm as the electricity travels up your body. Or maybe you’ve heard the importance of wire insulation? Wire insulation keeps an exposed wire from letting loose electricity that can cause a fire or even a shortage. Electricity is a huge benefit in our lives, but it is also highly dangerous. The articles written by your Los Angeles electrician are here to keep you safe. The experts at B.K. Electric Services will keep you from getting shocked.

The most common problem for parents of small children is the open outlet. Children, especially those of a young age, are curious people. They’ll put things in their mouth, they’ll pull down shiny items that might be on some high shelf, or what have you. Outlets are one of those things that interest the curious and children maybe want to stick their fingers in a live outlet. Oftentimes, a child may have a metal item in hand (for whatever reason) and wonder what would happen if metal met the outlet (hint: nothing good). There are plastic covers you can buy in bulk at the hardware store to keep this from happening. Invest in them.

If you’ve gotten a used appliance, perhaps at the discount store, the wires may have been treated with something other than kindness and have significantly worn-down insulation. If you find this to be the case, we hope you don’t ever plug this item in. You haven’t wasted your money, because you can get the wire repaired. Have an electrician take a look; chances are they (we hope us) can get it fixed.

GFCI outlets are designed to handle electrical loads that will be next water, such as in the bathroom or the kitchen. Some of us have a habit of charging our phones near the sink. Perhaps it’s not a cell phone charger, but an electric charger. The kitchen may host a blender or a toaster. GFCI outlets are faster at cutting the power when detecting an electrical surge (in this case, your body’s conduction) so fires and injuries can be avoided.

There are of course more tips we can cover, but you can read all about that in our collection of articles on our blog. If you have any questions and concerns, we invite you to give B.K. Electric Services a call today.

Posted in Blog

Jan 2014
Published January 23, 2014 | By admin.

Owning a business in Los Angeles can be expensive. There’s the rent to send in, supplies to buy, employees to pay, and if you have electrical equipment, you might be hoping nothing will break down. But if something should go awry with your electrical wiring or something similar, you need a Los Angeles electrician to help fix it fast! B.K. Electric Services stands by its prompt service and vast knowledge of all things electrical. And as a business ourselves, we understand how important it is that you get yours up and running fast. We’ve been handling electrical problems since 2009, which might be that long in some people’s eyes, but that’s only because we spent so much learning our trade!

Our electricians are learned individuals who have been tested, certified, and tested again. Electrical work can be dangerous for the electrician and the business owner if not done right so we only hire the best and keep each of our employees up-to-date on electrical standards. If you have sophisticated equipment that might require a specialist, give us a chance to take a look. We’re sure we’ll surprise you. And we always arrive on time and as professional as you would like in your own business. If our employees are going to wear our brand, we need to trust their judgment, their skill, and their professionalism.

A Los Angeles electrician needs to be reliable. Your business depends on our timeliness and our keeping our word. If we say we’ll be arriving at a certain time, we will be there; you can count on it. We’re a courteous group of people who will respect your workspace and keep you updated on what we’re doing. If you’re interested in an explanation, feel free to ask. It might slow us down a bit, we’re always happy to answer your questions; we’re interested in leaving you with a pleasant memory and a happy experience. Our electricians are communicative and polite, two qualities that should ensure a smooth repair and an even better relationship with your business and ours. So if you need a commercial electrician, feel free to call B.K. Electric Services.

Posted in Blog

Jan 2014
Published January 8, 2014 | By admin.

Electrical systems age every single day and eventually, like anything else, it needs maintenance to bring it back up to code and to prevent it from causing an electrical accident down the line. It’s recommended you hire an electrician to inspect your home and make any changes. A home rewire in Los Angeles can be a bit costly, depending on the size of the electrical system and the extent of the damage or basic wear-and-tear. Most electrical contractors provide free or low estimates so have several of them look into your home and then, compare their prices to your budget. This way, you can decide what changes to make without breaking the bank, as they say.

Most home rewires in Los Angeles won’t require that home is gutted, unless there is a major renovation or remodel taking place. Believe us when we say, a lot of the basic wiring is not going to be touched. We tend to build on the existing system or just replace those rewires that need replacing, like a flat tire on a car. The electricians at B.K. Electric Services understand you’re on a tight budget so let us know what additions you’ll want, if any, because each will take something out of your budget, leaving less for what you actually need.

Make a note of any switches or receptacles you’ll want to add. Again, keep in mind that an addition racks up the bill, so make sure it’s something you absolutely need rather than want. Each switch or outlet will require an extension of wire made to the electrical system. This means copper wire, which, though about $2-$5 a foot, is used extensively and the price adds up quickly. Ask yourself if there will be any work done in the attic or the basement. Electricians charge for labor and if the job is labor-intensive, the price goes up, but not by much. Will there be a new electrical panel installed? If so, this means additional circuits, so how many do you plan to have run through your home? Keep in mind the permits you’ll need. Check with the proper department of your city for permits. Any electrical work done without a permit is illegal and can cost you a large fine and a bad day in court.

Posted in Blog

Jan 2014
Published January 3, 2014 | By admin

1 – Business History

Hiring a contractor, in my experience, is a stressful task and only becomes marginally less so each time I’ve had to do it. But it helps to conduct some research into the business history of your candidates. It doesn’t take much time and will save you the legal trouble down the line. You’ll want to check with your state’s license board to verify that your contractor candidate is indeed licensed. I live in California, so my research will involve a visit to my state’s license board.

My license board provides more information on my contractor that is useful to me. Useful information includes whether the contractor carries worker’s compensation, property damage, and liability insurance. If he or she is a member of a reputable professional association, such as NECA or IBEW, it should be considered a good sign. You should be wary of some red flags, including evidence of having declared bankruptcy, evidence of legal action taken against your contractor, or a failing grade with the Better Business Bureau. A third party like the BBB provides objective, reliable reviews that can be an indicator to either cut loose your contractor or seek further references.

It’s important to confirm whether the contractorhas any recent, relevant experience, so get a list of references who have had projects similar in scope to yours and follow up with them. Don’t be shy about making phone calls and visits. Ask other customers questions about their experiences dealing with the contractor and their satisfaction with the finished product. You can obtain other third-party verifications from state licensing bodies, professional associations, state and local courts, insurance providers, suppliers, Better Business Bureaus and municipal departments.

A search into business history should include whether your prospective contractor has any recent or relevant experience. If he or she hasn’t worked in awhile, it may be due to a slow economy, your contractor’s bids have failed, or he or she may have some work policies that raised some flags for previous homeowners. Be sure to be thorough with your research. If you find a contractor who has worked jobs in similar scope to your project, don’t be scared about reaching out to his reference sheet.

At least five references from his most recent customers should do. Make phone calls, send emails, arrange visits if you can to former clients. Be sure to ask about timeliness and overall satisfaction. The more information you can gather, the better. You should be wary of contractors who are hesitant about handing out references or discussing past projects. This may point to troubled history on his part. If he refuses to provide his licensing and insurance info, run in the other direction. Fast. You don’t want to do business with that kind of contractor.

2 – Suppliers

A contractor who’s been plying his trade locally for five or 10 years has an established network of subcontractors and suppliers in the area and a local reputation to uphold. That makes them a safer bet than a contractor who’s either new to the business or planning to commute to your job from 50 miles away.

Every contractor has a reputation and a set of friends, even in a big town. If his reputation is a good one, people will gladly recommend you to him; if he’s as good as he says, they might ask him to godfather their child. The point is, a man is only as good as the friends he keeps and a contractor’s friends are his suppliers. If the contractor has been well-established in an area, he will have a network of subcontractors and suppliers in his work area that will gladly vouch for him.

If his professional reputation holds, these suppliers will offer testaments to his reliability and quality. One important item to ask for that often gets overlooked is an open account. Much like bars opening tabs for loyal customers, suppliers won’t have open accounts for just anybody. Check to see if his payments have been made on time or if there are any outstanding fines.

3 – Site Supervision

It’s important to ascertain during the course of the interview how the contractor plans on handling site supervision and subcontractors. For starters, a lot of the questions on the last page (such as those concerning licensing, payroll, liability insurance and workers’ comp) are inquiries you’ll need to put to any subcontractors as well — everyone on-site must be fully covered.

When talking to your contractor, raise the issue of site supervision. No matter the scale or scope of your project, any contractor worth his license should be able to provide a plan for organizing his subcontractors and their work. Be sure to ask if each and every one of his subcontractors is licensed and then, interview each and every one of them to be sure. Better to be thorough than sued. This is also beneficial to you if the contractor, for whatever reason doesn’t pay his workers. A laborer’s lien can be placed on your property to enforce payment or compensation to subcontractors and that can become very costly indeed. There are forms called lien waivers that the contractor, subcontractors, and suppliers sign that state they have received payment and waive any future lien rights to the property.

Further key questions center on work-site presence. How much time does the contractor propose to spend on your project each week, and how many other jobs is he or she completing in tandem to yours? Does the contractor plan on doing any of the actual labor, or is he or she mainly performing in a supervisory role? How often will the contractor be on-site, and who’ll be supervising during times when he or she isn’t there? A trustworthy and accountable presence should be on hand at all times.

Some key questions you shouldn’t forget to ask are whether the contractor will solely be working on your project alone or in tandem with other projects. If he will be working at other job sites, will there be a foreman or a like person to supervise during the actual labor? A contractor who insists on personally supervising every one of his projects is a good one, but not so if he is juggling multiple projects. This also ties into the time he will invest on your project. How many hours per week will he spend with you? Is he available in case of emergencies?

4 – The Foreman

I mentioned the foreman in the previous tip and he is, perhaps, the keystone of any construction project. Since many contractors are not actual tradesmen, often boasting little to no experience with actual labor, the job of project supervisor is delegated to his foreman, who is in charge of the construction crew.

The foreman is the person to speak to when the contractor is unavailable and will likely become your best friend during the duration of your project. He or she is working on your project every scheduled day and brings to the table years of experience in a specific field. Most foremen were construction workers who ascended to their position, so you can be sure that they know what they are talking about.

5 – Schedule

When interviewing a contractor, you should ask if he or she can provide a timeline for your proposed project, including fixed start and completion dates. Be sure to have these dates formalized in a written agreement. The timeline should also include a schedule down to the daily level of proposed labor and a list of materials. No project ever runs as smoothly as you would like so be sure to address how changes will affect the work schedule and contract.

During the project (provided you aren’t watching it unfold firsthand), you’ll probably want to check in once in a while to see how everything’s coming along. So it’s a good idea to ask the contractor how he or she plans on keeping you up-to-date and the process for scheduling site visits. Another related concern is determining the best way to stay in contact with the contractor so you can communicate any questions or concerns to him or her.

Before the project has begun, find out how you’ll be kept up-to-date on project proceedings and how you’ll be able to get ahold of your contractor when scheduling visits. A good project is completed with proper and multiple lines of communication as well as documentation that can be used in case your contractor becomes difficult.

If a contractor says, “We should be there in the next day or so,” keep looking. Are you supposed to wait around on a “maybe”? Or if it’s an emergency, you need a quick response, not an appointment a week from Tuesday. That’s why real-live human beings answer our phones 24 hours a day, 7 days a week, making intelligent scheduling decisions based on travel radius, availability and urgency.

I cannot stress reliability enough. I’ve been in situations where the contractor failed to show up at the agreed time and date. When I contacted them, I was given excuses or was told he was “on his way” and didn’t show up for another 2 hours. I’m not saying that a contractor should be waiting on you and be subject to your every whim. But you should be able to assume your contractor would respect the time he set up.

On that note, emergency service should warrant a quick response. Not an instant one, but relatively quick and suited to the circumstances. Appointments for a week later in such a situation are no good and you should move on to the next contractor.

6 – Guarantees

No one likes surprises when doing business with another individual or company. That’s why we draw up contracts that bind the involved parties to certain stipulations and can used to hold said parties to terms. This is just a long-winded way of saying that contracts are your only source of guarantees. Even if the contractor, during the course of the work, has a good day and decides to give you a discount, that “good day” discount is no good if it isn’t stipulated in a contract. Don’t sign off on anything without first understanding all terms and conditions. If needed, hire a lawyer.

Get used to creating and keeping a paper trail. Maintain records of all payments, invoices, etc. in case of any disputes that may arise in the course of your project. On the subject of permits, research any and all permits you even think you might need. Then, speak to your contractor and have him, in some shape or form, guarantee he will obtain the necessary permits and adhere to all laws of your city, county, and state. Do your homework. Believe me. You don’t want the kind of headache that accompanies the huge legal mess that awaits you if you don’t get written guarantees.

I wrote this previously, but I will do so again: keep a paper trail. You can’t take your contractor to court on the basis of a “he said, she said” claim.

7 – Estimates

And now we arrive at the estimates, perhaps the most important of all steps. Why? Money, plain and simple. No one works for free and if he does, he’s an intern, a volunteer, or he’s getting duped. And a contractor is none of these things. He, just like anyone else, expects to get paid, and you the homeowner, understand this. But you also don’t want to be duped or played for a fool. You’ll want to request an itemized price estimate from your prospective contractor. Examine each of these items carefully and cross-reference each item with further research that you have so obviously done.

Beware of the low estimates. This may be great news for you, but that usually means the contractor is cutting corners and is giving you low quality work. If the price is high, compare to other estimates from other contractors. If the difference isn’t much, don’t take it into account. If the difference is as wide as the ocean, that’s a red flag.

A schedule should also apply to payment with payments scheduled for work completed or for reaching certain milestones. However, it’s a balancing act. You’ll want to negotiate so you never pay for more than what you’ve gotten; if the work doesn’t make you happy, why should you pay for it?

8 – Routine

I touched upon the importance of communicating with your contractor and this includes asking about their work habits. They’ll be in your home for quite some time and you’ll have to learn to tolerate their little nuances, good or bad. Don’t be afraid to ask about your contractor’s routine. What makes them happy? How do they start their morning and should you be afraid of them in the morning due to surliness or grumpiness? How do they take care of their waste materials? How do organize their work materials and can you expect to have obstructions in your home?

Set a work schedule for yourself and insist on consistent reports from them. You don’t want to have to hunt them down for an update.

9 – Common Sense

Sometimes people forget the obvious things: don’t take candy from a stranger; if it smells bad, it probably tastes bad; a baker’s dozen is thirteen. Also, don’t hand over some cash for work. Cash is untraceable and you can get burned if the work is shoddy or illegal. That’s why you make the checks out to a business, which will assure you that your payment was recorded and you exist in their books.

Contractors aren’t paid under the counter, at least not the honest ones so if one asks you for an individual check made out to him and not the business, he’s probably not paying taxes on that income. If the contractor doesn’t even have a license, you’re in big trouble. If his work is sketchy at best or if he or the workers get injured, you’re liable for damages.

Posted in Blog

DEC 2013
Published December 22, 2013 | By admin.

Phantom power is electricity being pulled by appliances, even if they’re not turned on and or currently in use. These appliances are sometimes referred to as energy vampires and they are costing you money every single second they are left plugged in. Energy vampires are that phone charger you leave plugged into the wall because it would be less convenient to put it away when not in use. It’s that laptop you keep connected to the charger as well as the charger that is draining your account and running up your bill. That microwave you use to heat up some leftovers? A major energy vampire. If you think about it, your house is a haven for energy vampires.

Phantom power is also known as standby power. It’s what keeps the laptop charged enough to regain full power when you need it at a moment’s notice. Many microwaves come with a timer or a clock that is displayed when the appliance is not in use. This can be convenient, but the appliance draws more current than it is needed; instead of heating your food, you just end up with a large bill. Take a tour of your house or living quarters and look carefully. You’ll be surprised how many things you leave plugged in day to day.

You might think the energy you use isn’t that much, but much like smoking a cigarette, you do it long enough, you begin to hurt. And those bills don’t get smaller without some simple changes. The electricians in Los Angeles recommend using Energy Star products that are designed to save you energy with low maintenance. The power strip can help as a central “OFF” station. You can plug most small appliances into the power strip and just turn it off when not in use.

Nearly 10% of electricity is wasted to energy vampires. The television is one of the biggest offenders here with about $200 annually. Unplug it when you leave the house and any VCRs, DVD players, and gaming systems that use the television.

Posted in Blog | Tagged Electricity, energy, Power, vampire

DEC 2013
Published December 16, 2013 | By admin.

Have you noticed the cold weather in the area lately? The Los Angeles electricians at B.K. Electric Services sure have. We’re preparing for nasty weather that may result in unwanted power outages all over the county. You might doubt that our area will experience any serious rain that may cause a power outage, but anything can happen, if Murphy’s Law holds. You should always be prepared. One of the easiest ways to prepare is to have a flashlight conveniently located somewhere in the house. Remember, you’ll have to find it in the dark, so place it somewhere easily accessible by you or a member of your home and don’t forget the fresh batteries!

You’ll want to check the circuit breaker, wherever that may be located. If it’s in a storage closet, the garage, or in the basement, have your flashlight ready. Check to see if any breaker has been turned off. This should usually fix the problem as power surges are one the most common causes of power outages in the home.

If you’ve flipped the switch on that circuit breaker on and off and nothing is happening, the problem isn’t in your circuit breakers, but somewhere beyond your home, in one the power lines that feed energy to homes and businesses. With the wind so high lately, you’ll want to prepare for trees toppling onto power lines. If this is the case, make a call to your power company, who have their own electricians to fix this sort of thing.

Sometimes, the problem is in your home, but it isn’t something the common homeowner can fix. There might be an internal connection that has been burned out by massive power surge that resulted in a power outage. In rare cases, the circuit breakers and the main control panel breaker will be in the ON position, but the power will not turn back on. In this case, you should go and check every outlet on every power line of your home. Sometimes, it’s a faultly outlet and sometimes it’s an overload that has affected your entire system. If this is the case, you’ll have to replace some fuses and breakers, which can be tedious.

Posted in Blog

NOV 2013
Published November 11, 2013 | By kristian dept.

You’ve probably seen calculators with solar cells — devices that never need batteries and in some cases, don’t even have an off button. As long as there’s enough light, they seem to work forever. You may also have seen larger solar panels, perhaps on emergency road signs, call boxes, buoys and even in parking lots to power the lights.

Although these larger panels aren’t as common as solar-powered calculators, they’re out there and not that hard to spot if you know where to look. In fact, photovoltaics — which were once used almost exclusively in space, powering satellites’ electrical systems as far back as 1958 — are being used more and more in less exotic ways. The technology continues to pop up in new devices all the time, from sunglasses to electric vehicle charging stations.

The hope for a “solar revolution” has been floating around for decades — the idea that one day we’ll all use free electricity fro­m the sun. This is a seductive promise, because on a bright, sunny day, the sun’s rays give off approximately 1,000 watts of energy per square meter of the planet’s surface. If we could collect all of that energy, we could easily power our homes and offices for free.

In this article­, we will examine solar cells to learn how they convert the sun’s energy directly into electricity. In the process, you will learn why we’re getting closer to using the sun’s energy on a daily basis, and why we still have more research to ­do before the process becomes cost-effective.

The solar cells that you see on calculators and satellites are also called photovoltaic (PV) cells, which as the name implies (photo meaning “light” and voltaic meaning “electricity“), convert sunlight directly into electricity. A module is a group of cells connected electrically and packaged into a frame (more commonly known as a solar panel), which can then be grouped into larger solar arrays, like the one operating at Nellis Air Force Base in Nevada.

Photovoltaic cells are made of special materials called semiconductors such as silicon, which is currently used most commonly. Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material. This means that the energy of the absorbed light is transferred to the semiconductor. The energy knocks electrons loose, allowing them to flow freely.

PV cells also all have one or more electric field that acts to force electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, we can draw that current off for external use, say, to power a calculator. This current, together with the cell’s voltage (which is a result of its built-in electric field or fields), defines the power (or wattage) that the solar cell can produce.

That’s the basic process, but there’s really much more to it. On the next page, let’s take a deeper look into one example of a PV cell: the single-crystal silicon cell.

Silicon has some special chemical properties, especially in its crystalline form. An atom of sili­con has 14 electrons, arranged in three different shells. The first two shells — which hold two and eight electrons respectively — are completely full. The outer shell, however, is only half full with just four electrons. A silicon atom will always look for ways to fill up its last shell, and to do this, it will share electrons with four nearby atoms. It’s like each atom holds hands with its neighbors, except that in this case, each atom has four hands joined to four neighbors. That’s what forms the crystalline structure, and that structure turns out to be important to this type of PV cell.

The only problem is that pure crystalline silicon is a poor conductor of electricity because none of its electrons are free to move about, unlike the electrons in more optimum conductors like copper. To address this issue, the silicon in a solar cell has impurities — other atoms purposefully mixed in with the silicon atoms — which changes the way things work a bit. We usually think of impurities as something undesirable, but in this case, our cell wouldn’t work without them. Consider silicon with an atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, but in a sense, the phosphorous has one electron that doesn’t have anyone to hold hands with. It doesn’t form part of a bond, but there is a positive proton in the phosphorous nucleus holding it in place.

When energy is added to pure silicon, in the form of heat for example, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons, called free carriers, then wander randomly around the crystalline lattice looking for another hole to fall into and carrying an electrical current. However, there are so few of them in pure silicon, that they aren’t very useful.

But our impure silicon with phosphorous atoms mixed in is a different story. It takes a lot less energy to knock loose one of our “extra” phosphorous electrons because they aren’t tied up in a bond with any neighboring atoms. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping, and when doped with phosphorous, the resulting silicon is called N-type (“n” for negative) because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon.

The other part of a typical solar cell is doped with the element boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type (“p” for positive) has free openings and carries the opposite (positive) charge.

B­efore now, our two separate pieces of silicon were electrically neutral; the interesting part begins when you put them together. That’s because without an electric field, the cell wouldn’t work; the field forms when the N-type and P-type silicon come into contact. Suddenly, the free electrons on the N side see all the openings on the P side, and there’s a mad rush to fill them. Do all the free electrons fill all the free holes? No. If they did, then the whole arrangement wouldn’t be very useful. However, right at the junction, they do mix and form something of a barrier, making it harder and harder for electrons on the N side to cross over to the P side. Eventually, equilibrium is reached, and we have an electric field separating the two sides.

This electric field acts as a diode, allowing (and even pushing) electrons to flow from the P side to the N side, but not the other way around. It’s like a hill — electrons can easily go down the hill (to the N side), but can’t climb it (to the P side).

When light, in the form of photons, hits our solar cell, its energy breaks apart electron-hole pairs. Each photon with enough energy will normally free exactly one electron, resulting in a free hole as well. If this happens close enough to the electric field, or if free electron and free hole happen to wander into its range of influence, the field will send the electron to the N side and the hole to the P side. This causes further disruption of electrical neutrality, and if we provide an external current path, electrons will flow through the path to the P side to unite with holes that the electric field sent there, doing work for us alo­ng the way. The electron flow provides the current, and the cell’s electric field causes a voltage. With both current and voltage, we have power, which is the product of the two.

There are a few more components left before we can really use our cell. Silicon happens to be a very shiny material, which can send photons bouncing away before they’ve done their job, so an antireflective coating is applied to reduce those losses. The final step is to install something that will protect the cell from the elements — often a glass cover plate. PV modules are generally made by connecting several individual cells together to achieve useful levels of voltage and current, and putting them in a sturdy frame complete with positive and negative terminals.

How much sunlight energy does our PV cell absorb? Unfortunately, probably not an awful lot. In 2006, for example, most solar panels only reached efficiency levels of about 12 to 18 percent. The most cutting-edge solar panel system that year finally muscled its way over the industry’s long-standing 40 percent barrier in solar efficiency — achieving 40.7 percent [source: U.S. Department of Energy]. So why is it such a challenge to make the most of a sunny day?

Visible light is only part of the electromagnetic spectrum. Electromagnetic rad­iation is not monochromatic — it’s made up of a range of different wavelengths, and therefore energy levels. (See How Light Works for a good discussion of the electromagnetic spectrum.)

Light can be separated into different wavelengths, which we can see in the form of a rainbow. Since the light that hits our cell has photons of a wide range of energies, it turns out that some of them won’t have enough energy to alter an electron-hole pair. They’ll simply pass through the cell as if it were transparent. Still other photons have too much energy. Only a certain amount of energy, measured in electron volts (eV) and defined by our cell material (about 1.1 eV for crystalline silicon), is required to knock an electron loose. We call this the band gap energy of a material. If a photon has more energy than the required amount, then the extra energy is lost. (That is, unless a photon has twice the required energy, and can create more than one electron-hole pair, but this effect is not significant.) These two effects alone can account for the loss of about 70 percent of the radiation energy incident on our cell.

Why can’t we choose a material with a really low band gap, so we can use more of the photons? Unfortunately, our band gap also determines the strength (voltage) of our electric field, and if it’s too low, then what we make up in extra current (by absorbing more photons), we lose by having a small voltage. Remember that power is voltage times current. The optimal band gap, balancing these two effects, is around 1.4 eV for a cell made from a single material.

We have other losses as well. Our electrons have to flow from one side of the cell to the other through an external circuit. We can cover the bottom with a metal, allowing for good conduction, but if we completely cover the top, then photons can’t get through the opaque conductor and we lose all of our current (in some cells, transparent conductors are used on the top surface, but not in all). If we put our contacts only at the sides of our cell, then the electrons have to travel an extremely long distance to reach the contacts. Remember, silicon is a semiconductor — it’s not nearly as good as a metal for transporting current. Its internal resistance (called series resistance) is fairly high, and high resistance means high losses. To minimize these losses, cells are typically covered by a metallic contact grid that shortens the distance that electrons have to travel while covering only a small part of the cell surface. Even so, some photons are blocked by the grid, which can’t be too small or else its own resistance will be too high.

Wh­at would you have to do to power your house with solar energy? Although it’s not as simple as just slapping some modules on your roof, it’s not extremely difficult to do, either.

First of all, not every roof has the correct orientation or angle of inclination to take full advantage of the sun‘s energy. Non-tracking PV systems in the Northern Hemisphere should ideally point toward true south, although orientations that face in more easterly and westerly directions can work too, albeit by sacrificing varying degrees of efficiency. Solar panels should also be inclined at an angle as close to the area’s latitude as possible to absorb the maximum amount of energy year-round. A different orientation and/or inclination could be used if you want to maximize energy production for the morning or afternoon, and/or the summer or winter. Of course, the modules should never be shaded by nearby trees or buildings, no matter the time of day or the time of year. In a PV module, if even just one of its cells is shaded, power production can be significantly reduced.

If you have a house with an unshaded, southward-facing roof, you need to decide what size system you need. This is complicated by the facts that your electricity production depends on the weather, which is never completely predictable, and that your electricity demand will also vary. Luckily, these hurdles are fairly easy to clear. Meteorological data gives average monthly sunlight levels for different geographical areas. This takes into account rainfall and cloudy days, as well as altitude, humidity and other more subtle factors. You should design for the worst month, so that you’ll have enough electricity year-round. With that data and your average household demand (your utility bill conveniently lets you know how much energy you use every month), there are simple methods you can use to determine just how many PV modules you’ll need. You’ll also need to decide on a system voltage, which you can control by deciding how many modules to wire in series.

The thought of living at the whim of the weatherman probably doesn’t thrill most people, but three main options can ensure you still have power even if the sun isn’t cooperating. If you want to live completely off the grid, but don’t trust your PV panels to supply all the electricity you’ll need in a pinch, you can use a backup generator when solar supplies run low. The second stand-alone system involves energy storage in the form of batteries. Unfortunately, batteries can add a lot of cost and maintenance to a PV system, but it’s currently a necessity if you want to be completely independent.

The alternative is to connect your house to the utility grid, buying power when you need it and selling it back when you produce more than you use. This way, the utility acts as a practically infinite storage system. Keep in mind though, government regulations vary depending on location and are subject to change. Your local utility company may or may not be required to participate, and the buyback price can vary greatly. You’ll also probably need special equipment to make sure the power you’re looking to sell the utility company is compatible with their own. Safety is an issue as well. The utility has to make sure that if there’s a power outage in your neighborhood, your PV system won’t continue to feed electricity into power lines that a lineman will think are dead. This is a dangerous situation called islanding, but it can be avoided with an anti-islanding inverter — something we’ll get to on the next page.

If you decide to use batteries instead, keep in mind that they’ll have to be maintained, and then replaced after a certain number of years. Most solar panels tend to last about 30 years (and improved longevity is certainly one research goal), but batteries just don’t have that kind of useful life [source: National Renewable Energy Laboratory]. Batteries in PV systems can also be very dangerous because of the energy they store and the acidic electrolytes they contain, so you’ll need a well-ventilated, nonmetallic enclosure for them.

Although several different kinds of batteries are commonly used, the one characteristic they should all have in common is that they are deep-cycle batteries. Unlike your car battery, which is a shallow-cycle battery, deep-cycle batteries can discharge more of their stored energy while still maintaining long life. Car batteries discharge a large current for a very short time — to start your car — and are then immediately recharged as you drive. PV batteries generally have to discharge a smaller current for a longer period of time (such as at night or during a power outage), while being charged during the day. The most commonly used deep-cycle batteries are lead-acid batteries (both sealed and vented) and nickel-cadmium batteries, both of which have various pros and cons.

The use of batteries requires the installation of another component called a charge controller. Batteries last a lot longer if they aren’t overcharged or drained too much. That’s what a charge controller does. Once the batteries are fully charged, the charge controller doesn’t let current from the PV modules continue to flow into them. Similarly, once the batteries have been drained to a certain predetermined level, controlled by measuring battery voltage, many charge controllers will not allow more current to be drained from the batteries until they have been recharged. The use of a charge controller is essential for long battery life.

The other problem besides energy storage is that the electricity generated by your solar panels, and extracted from your batteries if you choose to use them, is not in the form that’s supplied by your utility or used by the electrical appliances in your house. The electricity generated by a solar system is direct current, so you’ll need an inverter to convert it into alternating current. And like we discussed on the last page, apart from switching DC to AC, some inverters are also designed to protect against islanding if your system is hooked up to the power grid.

Most large inverters will allow you to automatically control how your system works. Some PV modules, called AC modules, actually have an inverter already built into each module, eliminating the need for a large, central inverter, and simplifying wiring issues.

Throw in the mounting hardware, wiring, junction boxes, grounding equipment, overcurrent protection, DC and AC disconnects and other accessories, and you have yourself a system. You must follow electrical codes (there’s a section in the National Electrical Code just for PV), and it’s highly recommended that a licensed electrician who has experience with PV systems do the installation. Once installed, a PV system requires very little maintenance (especially if no batteries are used), and will provide electricity cleanly and quietly for 20 years or more.

We’ve talked a lot about how a typical PV system operates, but issues concerning cost-effectiveness (which we’ll get into more on the next page) have spurred endless research efforts aimed at developing and fine-tuning new ways to make solar power increasingly competitive with traditional energy sources.

For example, single-crystal silicon isn’t the only material used in PV cells. Polycrystalline silicon is used in an attempt to cut man­ufacturing costs, although the resulting cells aren’t as efficient as single crystal silicon. Second-generation solar cell technology consists of what’s known as thin-film solar cells. While they also tend to sacrifice some efficiency, they’re simpler and cheaper to produce — and they become more efficient all the time. Thin-film solar cells can be made from a variety of materials, including amorphous silicon (which has no crystalline structure), gallium arsenide, copper indium diselenide and cadmium telluride.

Another strategy for increasing efficiency is to use two or more layers of different materials with different band gaps. Remember that depending on the substance, photons of varying energies are absorbed. So by stacking higher band gap material on the surface to absorb high-energy photons (while allowing lower-energy photons to be absorbed by the lower band gap material beneath), much higher efficiencies can result. Such cells, called multi-junction cells, can have more than one electric field.

Concentrating photovoltaic technology is another promising field of development. Instead of simply collecting and converting a portion of whatever sunlight just happens to shine down and be converted into electricity, concentrating PV systems use the addition of optical equipment like lenses and mirrors to focus greater amounts of solar energy onto highly efficient solar cells. Although these systems are generally pricier to manufacture, they have a number of advantages over conventional solar panel setups and encourage further research and development efforts.

All these different versions of solar cell technology have companies dreaming up applications and products that run the gamut, from solar powered planes and space-based power stations to more everyday items like PV-powered curtains, clothes and laptop cases. Not even the miniature world of nanoparticles is being left out, and researchers are even exploring the potential for organically produced solar cells.

Some people have a flawed concept of solar energy. While it’s true that sunlight is free, the electricity generated by PV systems is not. There are lots of factors involved in determining whether installing a PV system is worth the price.

First, there’s the question of where you reside. People living in sunny parts of the world start out with a greater advantage than those settled in less sun-drenched locations, since their PV systems are generally able to generate more electricity. The cost of utilities in an area should be factored in on top of that. Electricity rates vary greatly from place to place, so someone living farther north may still want to consider going solar if their rates are particularly high.

Next, there’s the installation cost; as you probably noticed from our discussion of a household PV system, quite a bit of hardware is needed. As of 2009, a residential solar panel setup averaged somewhere between $8 and $10 per watt to install [source: National Renewable Energy Laboratory]. The larger the system, the less it typically costs per watt. It’s also important to remember that many solar power systems don’t completely cover the electricity load 100 percent of the time. Chances are, you’ll still have a power bill, although it’ll certainly be lower than if there were no solar panels in place.

Despite the sticker price, there are several potential ways to defray the cost of a PV system for both residents and corporations willing to upgrade and go solar. These can come in the form of federal and state tax incentives, utility company rebates and other financing opportunities. Plus, depending on how large the solar panel setup is — and how well it performs — it could help pay itself off faster by creating the occasional surplus of power. Finally, it’s also important to factor in home value estimates. Installing a PV system is expected to add thousands of dollars to the value of a home.

Right now, solar power still has some difficulty competing with the utilities, but costs are coming down as research improves the technology. Advocates are confident that PV will one day be cost-effective in urban areas as well as remote ones. Part of the problem is that manufacturing needs to be done on a large scale to reduce costs as much as possible. That kind of demand for PV, however, won’t exist until prices fall to competitive levels. It’s a catch-22. Even so, as demand and module efficiencies rise constantly, prices fall, and the world becomes increasingly aware of the environmental concerns associated with conventional power sources, it’s likely photovoltaics will have a promising future.

Posted in Uncategorized

OCT 2013
Published October 14, 2013 | By admin.

Use the Crock Pot.This slow cooker thrived during the 1970s as it allowed working women to start cooking dinner in the morning and finish up in the evening. The advantage of the Crock Pot is that it maintains a low temperature, which means less energy consumption. This also means the rest of your home won’t be turned into a furnace by the resulting heat.

Use appliances at night.Many utility companies offer discounted rates for off-peak energy usage. Typically, this period begins at around 8PM, but that depends on where you live and what company provides your utilities. Remember that laundry machines and dishwashers consume a good deal of energy. It wouldn’t be the worst thing in the world to clean dishes and clothes in the evening to lower that energy bill.

Use cold water to wash laundry.As I mentioned above, laundry machines account for a good deal of your energy bill and this is mainly attributed to how much energy it takes to heat water. Switch over to cold water for added savings.

Air dry laundry.While we’re discussing laundry, it’s recommended that you air dry your laundry. Dryers require a lot of energy to heat your clothes, so if you have the space and the time, try hanging your clothes out on a line or hanger and let Mother Nature save you some money on that energy bill.

Seal any leaks.If you’re trying to heat up your home and cool it down, it’s best if that air can’t escape. Most homeowners are unaware of these crevices and holes that allow air to seep through to the outside. Take some time to do a run-through of your home with some caulking or weatherstrips and cover those escape hatches! Close off any rooms that you aren’t using, as well as the ducts to those rooms.

Unplug or turn off electronics.This one is kind of a no-brainer. Maybe you’ve heard the myth about computers using less energy when they’re left on as opposed to repeatedly switching them on and off. This was true when computers were these large, gray, and energy hungry. But the modern computer has come a long way since then; the energy surge created when powering one on isn’t even comparable to the amount of energy used if left on. Use a power strip instead and get into the habit of turning that strip off when you leave your home.

No lights before night.Turn off your lights when they’re not in use. If you’re not going to be in a room or your house, shut off the light. Not only are you wasting energy by illuminating an empty home, but you produce heat and raise the temperature. Also, switch ligh bulbs if you can. Read our post on bulbs for more information.

Fans are your friends.Small spaces are easier to heat or keep cool because the air can be circulated without too much effort. Because the temperature is maintained, you don’t feel the need to play with the thermostat.

However, for those with larger homes, keeping that temperature at just the right level is a challenge. Since heat rises, you want to make sure you don’t have any air leaks in the ceiling if you want to stay warm. Ceilings fans are great since you can choose in which direction the blades will spin. A clockwise spin pushes the air down, which means that heat is recirculated in your home. If you want to keep cool in the summer, a counter-clockwise spin draws that air up and away.

Check and replace filters. Dirty filters keep air from flowing through. This means your AC or central heating unit has to work harder to get air where you want it. Check filters regularly and replace them when they become restrictive.

Posted in Blog

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