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Solar Photovoltaic | Solar Hot Water
Solar Photovoltaic
What does “photovoltaic” mean?
The word itself helps to explain how photovoltaic technologies work. The word has two parts: photo, meaning light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. Thus photovoltaic literally translates to light-electricity.
What is solar electricity?
Solar electric technology converts sunlight directly into electricity. Solar energy is possible anytime sunlight is evident, but more electricity is produced with more intense and direct sunlight.
How do solar panels work?
Solar panels are mostly silicon based, a material that is a great absorber of light and energy. The solar light excites the free electrons in the solar panels and DC electricity is created. However, DC is not a usable form of electricity. The electricity that is created in the solar panel travels through the panel’s wires to the inverter, which converts the DC power to applicable and usable AC power. This AC power is then hiccupped back into the utility grid and through your electric meter, powering your home or facility.
What is the significance of the fact that solar is a renewable energy source?
Unlike traditional power generation sources, these technologies produce electricity using a renewable source—the sun—without creating noise, emitting pollutants that cause climate change such as smog and acid rain, or polluting our water resources. Even when the emissions related to solar cell manufacturing are counted, photovoltaics produce less than 15% of the carbon dioxide from a conventional coal-fired power plant. In fact, using solar electricity to power a million homes would reduce carbon dioxide emissions by 4.3 million tons per year, the equivalent of removing 850,000 cars from the road (Source: Environmental Protection Agency (EPA)).
What are the components of a solar system?
The major components of a solar system installation include solar panels, an inverter, wiring, combiner box, and wiring system. The solar panel is the basis of the solar system. A “solar array” is the arrangement of numerous solar modules, connected via a wiring network. The number of solar modules determines the amount of power that will be produced by the system. The wiring system refers to the string of wires which connect every adjoining solar module, creating a fully connected and linked solar array. The combiner box allows for the wires to safely be routed in an orderly manner, minimizing the change of shorting caused by pinched or abraded wires, before routing the connected wires to the inverter. The inverter’s function is converting the DC power, or Direct Current, into usable AC power, or Alternating Current. Inverters are rated by wattage and the quality of their output.
What determines the size of a solar energy system?
Several factors determine the size of a solar energy system. To determine the appropriate solar installation to best match your needs, the following must be considered: how much electricity you use, how much sunshine is available at your location, the size of your roof, how much you are willing to invest, and the government incentives that are available for you to install a solar energy system. The AGT engineers will then personalize a system layout specific to your needs.
Will my system work at night?
No, solar power cannot generate energy at night as sunlight must be present for your solar modules to produce power. At night, you draw power from your utility.
Will my system work on cloudy days?
Yes, your system will work on cloudy days, but it will produce less electricity. Through an overcast sky, panels produce approximately half as much as under full sun.
Are batteries necessary?
Batteries add about thirty percent to the cost of an installation causing them to be an expense and an unnecessary addition to most installations. Batteries are necessary in an off-grid installation most commonly utilized in remote locations without any utility power. Batteries are also used as back up for a home in the event of a power outage. Depending on how self-sufficient you want your unit to be, you may decide to remain grid tied into the electric company’s power system, or with the installation of batteries and the ability to store energy you would be “off-grid”.
What happens during a power outage?
Being off-grid allows you to generate power during an outage. However, remaining on-grid and tied into the utility company leaves you susceptible to loss of power during a power outage.
What are the advantages and disadvantages to being ‘off-grid’?
The term off-grid refers to living in a self-sufficient, autonomous manner without reliance on public utilities. Electrical power can be generated on-site with renewable energy sources such as solar, wind or geothermal. Living off-grid is the only way to go if you live in a remote area where there are no utilities. However, some people opt to have their system conducted to be off-grid even when living within an area that allows you to be on-grid. Some advantages to being off-grid are the idea of independence from utilities, freedom from worries about utility rate increases, and the ability to self power if the power goes out. Additionally for environmental-minded individuals, due to the cost of an off-grid system, many find themselves forced to conserve energy rather than expand the system to generate more power. There are some disadvantages to being off-grid also. Instead of the utility company maintaining your system, you’ll be the sole maintainer of your utilities. The expense of batteries is also considerable at a cost of at least $1,000, and the need to replace them every 5-15 years. In addition to the cost of the batteries is the fact that they are partially inefficient, starting out at a production of about 90% efficiency. Furthermore, being off-grid does not allow you to feed excess energy that is generated back to the utility company allowing you an energy credit.
Is shade a problem?
Crystalline panels are connected across the entire panel, and need a direct sun connection across the whole module in order to function. However, FlexLight thin-film panels contain bypass diodes throughout the module that allow the panel to continue to produce if there is shading or sever damage to a portion of the panel.
What factors are considered when determining a system’s layout?
A comprehensive roof analysis and site assessment is conducted prior to installation. Many factors are considered to maximize your installation’s efficiency including, average electrical consumption of the facility, location of the building, structural and natural surroundings, climate, roof angle, and shading. Our engineers are experienced in configuring the most suitable and efficient layout for your energy needs while considering all structural factors.
Will a system produce enough energy to cover all my electricity needs?
It is important to value a solar electric systems contribution to providing you electricity and understanding that a solar installation does not need to cover all your electricity demands to be a great asset. An average residential system installation will displace an average of one-quarter to one-half of your average electricity demand and your electricity bill. A system that supplies all of your energy needs is possible, but typically the most cost effective installation will cut your electricity by forty to fifty percent.
How can I tell how my system is performing?
Every home contains a power meter telling you exactly how much electricity you generate and use, and when you are send power back to the utility grid. If a grid tied system produces more power than the appliances in the building are using the meter will spin backward.
AGT also offers a system monitoring device and service with every installation. A data module monitoring chip is factory installed in each inverter providing real time feed of the system production. This data chip allows for detailed power data reported with better than +/- 5% accuracy. The monitor chip detects system interruption and data glitches while feeding instant email alerts to programmers, allowing them to maintain constant vigilance of installations and immediately dispatch an onsite assessment. System data/performance can be accessed through a high-speed internet connection and provides you with current weather condition, AC output, lifetime kilowatt hours, system offsets/efficiency, and daily kilowatt hours produced. The AGT solar monitoring system also shows environment off-sets as a result of the system in tangible terms such as CO2 off-set, trees saved and waste recycled rather than land-filled. To see a live solar monitor system, visit www.AGTSolarDemo.com.
What maintenance does the system require?
Your system should go years, even decades, without problems. We recommend that the installer conduct a system check once a year, just to ensure everything is performing as it should. Otherwise, you can clean the modules two or three times a year with water to rid it of dust and debris. If your system includes batteries, they may need to be replaced every five to ten years.
What happens if snow covers my solar panels?
After a snow storm, when the sun comes out, the solar radiation penetrates the snow and heats up the collector melting the snow from the bottom up. The melting at the surface of the collector allows the snow to slide off. Additionally, since the panels are usually mounted at an angle, the snow is able to slide off fairly easily.
Do I need special insurance requirements?
Standard homeowner or building insurance policies usually suffice to meet electric utility requirements. Electric utilities usually require that owners who take advantage of net metering sign an interconnection agreement.
Will my roof’s warranty be affected by a solar installation?
No, as long as you use a certified roofer, your roof’s warranty will be carried over. But be wary of contracting an uncertified/untrained individual to install your solar system. Besides making engineering and electrical mistakes, if a roof leak or issue occurs after installation your roofer may not be liable for warranty or inspection if your roof experienced a faulty solar installation. All AGT authorized roofing contractors are certified to install solar systems as per our training programs.
How much does a residential solar system installation typically cost?
An average, residential system size is approximately 2kW, costing approximately $20,000. This total includes the cost for all components – solar panels, panel mounts, inverter, and labor associated with installation. However, this cost does not include the deductions from rebates, credits, incentives, and tax breaks offered from the government for a solar installation. AGT sales representatives are skilled in providing a financial model which incorporates every available and applicable incentive and rebate for your installation. A very resourceful website, www.dsire.org, lists the breakdown of state incentives.
How much will my utility bill be off-set from a solar installation?
The first factor to consider is how much electricity you use. Other determining factors are your location and the size of your installation. How much you will save on your utility bill monthly varies but typically a residential solar installation can reduce your homes energy bill by one-half.
Is a building permit required to install a solar energy system on my home?
Yes, you will need to obtain building permits to install. Similarly, building, electrical, and plumbing codes also apply. Solar contractors include the price for permits into their cost estimate.
Will my meter spin backwards?
If your solar system is producing more electricity than is being consumed at a given moment, your meter will spin backwards. This excess energy is registered on your meter and credited from your utility company as it flows back to the main grid of your electric company. This credit can be used later during the night or on a cloudy day.
What is ‘Net Metering’?
This means that your utility company will give you the same retail rate for electricity that you “sell back” to the utility. Every utility will have different rules for this, but the basic premise is that they will buy electricity from you at the same rate that you buy electricity from them.
If I sell my property, will my solar installation have an effect on the sale price?
Energy conservation and renewable generation adds value to a property. Solar energy can be one of the best improvement investments you make. The top selling point of raising resell value is that the new owners will inherit a building retrofitted to reduce overhead cost on heating, cooling and appliances. Make sure to emphasize the value that a solar installation brings and market this in the list of extras. According to the Appraisal Journal in the October 1998 article, “Evidence of Rational Market Valuations for Home Energy Efficiency,” a home’s value is increased by $20,000 for every $1,000 reduction in annual operating costs from energy efficiency (Nevin, Rick et al).
What is the lifespan of a PV system?
A solar system’s lifetime is determined by the amount of wear and tear they encounter. The PV cells themselves will work indefinitely and produce electricity as long as they have contact with sunlight. Manufacturers provide a twenty five year warranties on most products, however most system owners report their systems continuous production way past the determined twenty five year lifespan.
My region is prone to high winds, such as hurricanes. Is PV safe for my area?
Yes, Advanced Green Technologies received the first Notice of Acceptance for a PV panel from Miami-Dade County. Their testing is considered to be the strictest for wind-load requirements. To receive this, the product must be able to withstand winds in excess of 146 mph.
What types of roofing materials can the FlexLight PV laminates be adhered to?
FlexLight solar laminates are sized to fit in the pans between the seams of a standing seam metal roof. However, they have the ability to be applied to a roof that has been covered with a single ply membrane such as TPO and EPDM. There are a few other situations such as a concrete and shingle roofs where FlexLight laminates can be applied. Please contact AGT to discuss your situation.
How old should my roof be to install PV?
Ideally it should be a new roof, or at least have enough to survive as long as your panels. This would mean that your roof should have 20 to 30 years of life left. Your installer or roofer would be best to make this assessment.
Can I install the system myself?
No, this is not a do it yourself project. In most states, you will need to have a licensed Solar Contractor or Electrical Contractor install the system to receive any available government rebates. Additionally, installing a solar installation yourself or not using a certified roofing contractor may nullify and void a warranty that your roof may carry. A solar installation is a valuable asset to your home and should be completed by an experienced professional in structural engineering and electrical knowledge.
Will my homeowners association allow me to install solar panels on my roof?
Yes, most states have to allow it. However, you should inform the board of what you are doing. For example, Florida state law (163.04) forbids ordinances, deed restrictions, covenants, or similar binding agreements from prohibiting solar equipment use. Under this law, a homeowner may not be denied by "any entity granted the power or right in any deed restriction, covenant or similar binding agreement to approve, forbid, control, or direct alteration of property..." permission to install a solar collector, clothesline, or other energy device using renewable resources.
What is a solar tracker?
These are generally pole mounted systems designed to follow the sun’s path during the day and through the different seasons to capture the maximum amount of sun. A solar tracker consists of a solar reflector or lens aimed toward the sun which gathers a concentrated amount of sunlight while tracing the sun's position in the sky as it varies both with the seasons and time of day as the sun moves across the sky. A solar tracker increases the effectiveness of solar energy at the cost of additional system complexity.
Solar Hot Water
How does a solar water heater work?
There are three main components of a solar water heater system: the controller, the collectors and the circulation module. The controller is the main component of the system. It consists of one sensor on the roof and one sensor on your water tank. When the controller senses that the temperature on the roof is warmer than the temperature in your tank, power is sent to the circulation module. The circulation module is where the heat from solar is transferred to your water heater. It circulates water up to the roof to be warmed by the sun, and then re-circulates the water from your water tank. The heat is transferred from the solar water to the useable water via a heat exchanger inside the circulation module. The solar panels are where the energy is collected from the sun. As the water flows through the panel, the heat is transferred to the water and then to the water heater in the heat exchanger.
Will a solar water heater replace my existing hot water heater?
No, a solar hot water system works in union with your existing gas or electric hot water heater. In most situations, the addition of a solar hot water system will extend the life of your existing system. You are adding an auxiliary system when you add solar domestic hot water, not replacing your current water heating set-up. As a result, you will have access to both types of water heating options and never be left without hot water.
How much does a residential solar hot water system typically cost?
Every home will have different demands for hot water. And each home will have a different roof, accessibility to the attic, distance between the solar collector and tank, etc., which all play a part in the cost of the system. Generally the installed cost, before government rebates and incentives, is between $3,500 and $7,000.
How much money can I expect to save on my utility bills?
It really depends on how much hot water you are using. For electric water heaters about 18-30% of a home’s electric bill goes towards heating water. Average return on investment for solar domestic hot water is between 3 to 5 years.
What incentives are available to me?
Incentives vary from state to state. A very resourceful website, www.dsire.org, lists the breakdown of state incentives. The United States Federal Government offers a 30% tax credit (up to $2,000). Some local power companies also offer local incentives, so check with you provider.
Can I install the system myself?
No, this is not a do it yourself project. In most states, you will need to have a licensed Solar Contractor or Plumbing Contractor install the system to receive your rebate. Additionally, installing a solar installation yourself or not using a certified roof may nullify and void a warranty that your roof may carry. A solar installation is a valuable asset to your home and should be completed by an experienced professional in structural engineering and electrical knowledge.
Will my homeowners association allow me to install solar panels on my roof?
Yes, most states have to allow it. However, you should inform the board of what you are doing. For example, Florida state law (163.04) forbids ordinances, deed restrictions, covenants, or similar binding agreements from prohibiting solar equipment use. Under this law, a homeowner may not be denied by "any entity granted the power or right in any deed restriction, covenant or similar binding agreement to approve, forbid, control, or direct alteration of property..." permission to install a solar collector, clothesline, or other energy device using renewable resources.
Will I ever run out of hot water?
No, the tanks are equipped with an electrical back-up heating element that will supplement the system when the sun is unable to provide enough heat.
How dependable is solar water heating system?
Solar water heating systems are known to be very dependable. With very few moving parts (sometime no moving parts) and an abundance of sun, solar water heating is more reliable than the electric company.
How long will it last?
Most systems are warranted to last between 20 and 30 years. However, many systems are known to work much longer than they are warranted for. Many solar water heaters from the energy crisis of the 1970’s are still in service today.
What are the environmental benefits of using a solar water heater?
An average American home (using an electric water heater) will consume as many barrels of oil (11.4 barrels) per year as the average American car. So converting an electric water heater to a solar water heater is the equivalent of removing a car off the road each year.
Will my solar water heating system survive a hurricane?
Not if properly installed. Solar collectors are engineered to withstand the wind load requirements of the 2004 Florida Building Code. Check with your Contractor to ensure that he or she is using equipment that will meet or exceed your local wind-load requirement.
Will it work on cloudy days and in the winter?
Yes. Solar collectors are sealed to produce the “greenhouse effect” which will collect and transfer as much of the sun’s heat as possible, even on cloudy or cool days.
Will it work in a cold climate?
Yes, your system can work in a cold climate. A properly designed and installed solar hot water (solar thermal) system can work in almost any climate. Cold climates have colder main temperatures. Because of this, the collectors can add energy to the system on a cold day. Also, snow surrounding the collector reflects sunlight onto the collector itself, making it more efficient.
Can a solar collector be installed on a barrel tile roof?
Yes. Solar collectors can be installed on just about any type of roofing material, including shingle, tile, metal, or flat roof.
How much space will it take up on the roof?
Many homes will only require one solar collector, which can be 4’x8’ (32 sq. ft.) or 4’x10’ (40 sq. ft.). Larger homes may require 2 solar collectors (64 sq. ft.) or (80 sq. ft.). The panels look similar to a skylight.
How long does it take to install?
In most cases, the job will be completed in one day.
I am not able to put a solar panel on my south-facing roof. Can I still go with solar water heating?
Yes, your contractor will advise you on the best spot on your roof for year-round performance, which may be on an east, west or even north-facing roof.
Does the system require any maintenance?
Very little maintenance is required, maybe an hour every 5 years. All water heaters (electric, gas, or solar) should have a few gallons drained from the bottom of the tank to purge sediment that will naturally accumulate.
Is it possible to do a ground mounted solar water heater system?
Yes, check with your installer to see if you have the proper location for solar collectors on the ground.
If a solar water heater is so efficient and practical, why doesn’t everyone have a solar water heater?
In many countries solar water heaters are a common place. In Israel about 90% of all homes use solar water heating. Other countries such as Germany, Canada, and China are world market leaders for manufacturing and installing solar water heaters. Temperate climates in areas such as Central America, the Caribbean, and Africa have been using solar water heating for hundreds of years. Half the population in Miami used solar water heating by 1941. And 80% of the homes built in Miami between 1937 and 1941 were equipped with solar water heaters.
Are there any other opportunities to use solar water heating at my home?
Yes, you can use solar hot water for radiant floor and space heating and to heat a swimming pool or spa.
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