Any time you have a need for electrical power and conventional hydro is not accessible, you have an application for Solar Energy!
Some of the more common uses are power for a remote cottage, a boat without access to shore power, or an RV when you are "dry camping". Even people who have hydro access but don't want the hassle and expense of burying cable, will take advantage of the benefits of Solar Power.
Photovoltaics is a wonderful energy source, the fuel is free, it is safe, silent and reliable and of course, environmentally friendly! It does however, have its limitations - for example running high demand loads like air conditioners.
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Energy is around us in a variety of forms: gasoline, running water, light, and electricity to name just a few. We often transfer energy from one form to another, for example, when an automobile uses chemical energy from fuel to move. Some types of energy are easy to store (i.e. chemical) and some are easy to move from one place to another (i.e. electricity and light).
Electricity is one from of energy that we have harnessed in the past 100 years. By definition, electricity is the energy available from the movement of electrons within a conducting material. It is analogous to water flowing out of a hose; the electrons are like drops of water. Enough electrons with force behind them can be used to do useful work.
Volts, Amps and Watts
The common units that are used to measure the quantity of electricity are:
Volts: Electrical force or pressure behind the electrons in a circuit. Analogous to water pressure or PSI, it tells us the system voltage (12, 24).
Amps: The number of electrons flowing past in a second. Like gallons per second in a pipe, it defines the electrical current in a wire.
Watts: Total amount of electrical energy, per second.
Amp Hours and Watt Hours
In power systems we describe the total amount of energy consumed over a certain period in either amp hours or watt hours. A one amp draw for four hours has used a total of 4 amp hours (AHr) of current. A 100 watt light bulb over 24 hours uses 2400 watt hours (WHr) or 2.4 kilowatt hours (kWHr) of energy. Note: a kilowatt equals 1000 watts, and a kilowatt hour equals 1000 watt hours. Your local hydro unit charges per kilowatt hour used.
AC Versus DC Current
Just to make things interesting, electrical energy is moved from place to place in two ways. Alternating current (AC) is the most common form; utility power arrives to us as high voltage AC current. Alternating current is like water sloshing back and forth in a bath, the same electrons doing the work in one spot. Solar panels and batteries produce direct current (DC), which is easier to store. DC current is usually used at lower voltages, i.e. 12 or 24VDC.
Advantages of Higher Voltages
In all power systems we have to move electricity from one place to another. The transfer is not 100% efficient, and we have to take care to minimize the power losses en route. In wire, the loss of electrical power is a factor of the resistance of the wire, and the amount of current going through it. If we use higher voltages, our current is less, so power losses will be lower.
Good sites for wind power will have average wind speeds of 16 to 24kph or more. There are locations on the coasts, prairies and in the arctic where wind systems are ideal as a primary power source due to the consistency of the wind speeds. Most places in Canada may have strong winds occasionally, but lighter winds most of the time. In this case, wind power is an excellent supplement to other charging sources. Wind power can compliment solar power, and in many places, this will give you this most power in the winter when sunlight is at a premium.
Wind Generator Ratings
Manufacturers pick a nominal wind speed at which to rate their wind generator, but there is not a standard wind speed that is used. Different models will perform better in lower wind speeds and others are designed for high wind areas. Comparing wind generator output curves will tell you the expected performance at each wind speed. The current output from a wind generator increases as the square of the wind speed, so don't expect a lot of power at low wind speeds even though the unit seems to be turning quite quickly.
Wind Site Selection
Steady winds without turbulence are a must for maximum power. The higher the wind generator is placed, the stronger the winds it will experience. Avoid trees and buildings that will "shadow" the wind generator. Placing it close to the batteries will minimize the line loss and cable size.
Propellers and wind generator vibration can cause a certain amount of noise. Placing the wind generator away from living quarters is recommended.
Wind Generator Installation
Access to the wind generator may be necessary, so a guyed tower with rungs is ideal. Spending time on top of a tower is not always fun, so making the wind generator easy to remove is a good idea. An electrical junction box is better than spliced connections as it makes disconnection easier. Hardware should be corrosion resistant and greased, especially in coastal areas.
Due to the height of towers and distance to the batteries, long cable lengths with wind systems are common. There are advantages to using higher voltage systems. Consult a wiring table and keep the line losses below 5% over the cable run.
Wind Generator Maintenance
All wind generators have moving parts. Bearings, brushes and shafts will all need occasional maintenance. Equipment exposed to salt water may need more frequent servicing than inland sites. Wear and tear due to normal operation can be fixed with replacement parts; however, this is not covered by the warranty.
Wind generators may be subjected to severe storm winds that can cause damage. Two blade models are more vulnerable than smaller fan blades due to extra vibration. Plastic blades are more durable than wooden blades. In very high winds, the wind generator should be switched off with a stop switch.
If your property has an adequate source of flowing water, then a small hydro system may be the most economical way of generating electricity for your home. Small hydro systems are simple, reliable and usually produce more power when you need it most, in the winter.
To take advantage of hydro power, your water source must provide both volume and pressure (head). If your creek or stream can deliver more than 45 litres (10 gallons) per minute, then you will have enough volume. Pressure is derived from the height the water falls vertically, called head, and expressed in meters or feet. A small hydro system needs at least 10 feet of head to provide usable amounts of power.
A small hydro system needs a turbine, alternator, and water jets aimed at the turbine, and a control circuit. You will also need a battery storage bank, regulator, and enough plumbing to get the water to the turbine, usually a 2" pipe or larger.
If you feel that hydro rates are outrageously expensive, you might consider renewable energy as an economical alternative. We would be pleased to offer you an independent power system to replace your utility; however, there are some important facts regarding cost and energy consumption that you should consider:
Independent power systems will run lights, water pumps, TV's, VCR's, satellite receivers, stereos, vacuums, washers, refrigerators, freezers (energy efficient designs), microwaves, kitchen appliances, computers, printers, faxes, power tools, irons, blow dryers, curling irons and much more.
Independent power systems will not run any major heat producing appliances. These energy gluttons include electric heat, hot water, electric ranges and clothes dryers. They use outrageous amounts of power; thousands of watts every minute that they run. By switching these to natural gas or propane and by purchasing energy efficient appliances, you can easily reduce your energy consumption to a fraction of what you usually purchase from the utility.
Independently powered homes must be set up like this before an affordable wind or solar system can be installed. This is most easily done when setting up a new home and making those appliance decisions for the first time. When building a new home, there are many ways of making the jump to a renewable energy system that is easier and cheaper. Feel free to contact us before you build to discuss your renewable energy system if you're serious about being off-grid.
If your energy bill is too high, you are using too much electricity. In most cases, utility companies don't even come close to covering their costs when they charge you the amount indicated on your bill. If they charged what it cost them to produce electricity, alternate energy sources could be more economical in most situations. Canadian electrical rates are the least expensive in the world.
Renewable energy systems will be more expensive, per kilowatt, than the energy billed to you from your local utility.
Independent power systems are designed with energy conservation in mind. Typical power production is in the range of 30 to 200 kilowatt-hours a month. The average Canadian home uses between 750 and 1500 kilowatt hours per period. Efficiency is the secret, therefore, conservation is essential.
Reduction of energy requirements is an essential prerequisite to producing your own electricity. It costs much less to change appliances to models that use just a fraction of the power. This will save hundreds of kilowatt hours each month.
Once all the above steps have been taken, your power bill will be much more manageable, perhaps 60-500 kilowatt hours. At this point it would be possible and practical to generate your own power, or a portion of your own power from renewable energy sources. If your goal is to lower your utility bill, you can achieve this by reducing energy requirements first and then starting to think about renewable energy systems.
When you require AC power (either 120V or 220V), a power inverter is your solution. An inverter will convert your 12 or 24V DC system to AC so that you can run your AC appliances. Some sensitive AC appliances do not operate well, or at all, on standard modified sine-wave inverters.
Two basic types of inverter output:
Modified Square/Modified Sine Wave:
Creates alternating current (AC) in 4 steps per cycle. Will run 90% of appliances, exceptions include some laser printers and cordless battery chargers (which brands have problems is a matter of trial and error). Some equipment will hum or experience interference from this inverter power.
Creates AC in upwards of 50 steps to closely approximate utility power. Will run any load with little or no hum or interference. Cost of these units is much greater.
Inverters are sized according to the loads that are likely to run at any given time +20%.
An inverter's input voltage is matched to the battery bank used in the system.
Inverters greater than approximately 800 watts in size do not have fusing on their DC input side and require an appropriate inline DC rated fuse - contact Solarstation Nigeria for more information.
The output of an inverter is connected to the AC breaker panel (main or sub panel) as if it were normal utility. All household wiring beyond the breaker panel can then be done according to standard building codes for AC, with some extensions - contact Solarstation Nigeria.
The installation of an inverter should follow the manufacturer's recommendations in their installation guides.
Some special features offered by inverter manufacturers:
Built-in battery chargers (stand-by models)
Allows a generator or utility line (i.e. RV park service) to be connected directly to the inverter as back-up or intermittent system support. The inverter will provide AC from the batteries. When the generator or utility is present the inverter transfers this power to the household appliances (loads) and uses what excess there is to charge the battery bank with its built-in charger. When generator is shut-off or utility is disconnected, the inverter will switch back to inverting from the batteries without disrupting the power going to the appliances. This is usually very quick at approximately 30ms.
Allows two inverters to be connected together to provide 120/240 service. Remote/Automatic generator start: Trace Sine Wave series only, or via separate generator start relay.
Lighting! Use fluorescent lighting whenever possible (they use 1/4 to 1/5 the amount of power as incandescent lights) i.e. a 20W compact fluorescent bulb is equivalent to an 80-100W standard light bulb. Halogen lights are only about twice as efficient as standard incandescents, but many people prefer their light to fluorescents.
Batteries are the one component of an alternative energy system which require diligent maintenance. Each cell in a battery supplies 2 volts, so a 6 volt battery has 3 cells, a 12 volt has 6 cells
The battery's capacity is rated in Amp-Hours (or amps at the 20 hour discharge rate in some literature) Solarstation Nigeria recommends the use of 6 volt deep-cycle batteries (ie. GOLF CART) for most small to medium sized residential/cottage/cabin applications for the following reasons:
Each cell in a 6 volt battery is larger than each cell in a 12 volt battery - thereby providing more capacity, better cycling performance (charging/discharging) and longer life. are relatively inexpensive and easy to find are more easily replaced if a bad cell develops Flooded batteries Typical wet batteries with caps on each cell for topping up with distilled water. The least expensive form of battery. Sealed batteries Slightly different internal construction and acid requiring a lower charging voltage Will not gas as much as flooded batteries Marketed as maintenance-free as they do not require watering or new acid Much more expensive than flooded batteries NiCd (Nickel Cadmium) Good for small systems (ie emergency lighting) Very expensive compared to other batteries
All batteries should be tested every 3 - 6 months to ensure proper charging and operation. This is done by testing with an accurate volt meter while no loads are attached (open circuit), or with a hydrometer which measures the specific gravity of the acid (a more exact method for flooded batteries only).
A full battery will measure 12.60 volts at rest A battery at 20% will have a voltage of 12.00 volts at rest
Do not add new batteries to an existing set which is more than 1 year old as the older cells will bring the new cells down to their current performance level. An older set which has been well used should ideally be replaced when increasing the size of the system. Do not discharge a battery below 50% of its rated capacity in order to ensure long life. The less a battery is worked, the longer it will last.
Equalize battery bank every 1- 6 months depending on use to preserve performance.
Other Technologies Other Technologies that are Beneficial when using Solar Energy
Other Technologies that are Beneficial when using Solar Energy
Energy from the sun travels to the earth in the form of electromagnetic radiation similar to radio waves, but in a different frequency range.Available solar energy is often expressed in units of energy per time per unit area, such as watts per square metre(W/m2).The amount of energy available from the sun outside the Earth’s atmosphere is approximately 1367 W/m2; thats nearly the same as a high power hair drier for every square meter of sunlight! Some of the solar energy is absorbed as it passes through the Earth’s atmosphere.As a result, on a clear day the amount of solar energy available at the Earth’s surface in the direction of the sun is typically 1000 W/m2.At any particular time, the available solar energy is primarily dependent upon how high the sun is in the sky and current cloud conditions.On a monthly or annual basis, the amount of solar energy available also depends upon the location.Furthermore, useable solar energy is depends upon available solar energy, other weather conditions, the technology used, and the application. There are many ways that solar energy can be used effectively.Applications of solar energy use can be grouped into there are three primary categories: heating/cooling, electricity production, and chemical processes.The most widely used applications are for water and space heating.Ventilation solar air heating is also growing in popularity.Uptake of electricity producing solar technologies is increasing for the applications photovoltaics (primarily) and concentrating solar thermal-electric technologies.Due to recent advances in solar detoxification technologies for cleaning water and air, these applications hold promise to be competitive with conventional technologies.
Solar energy has the following advantages over conventional energy:
In combination with a few other technologies, the effectiveness of solar heating can be maximized. Listed below are a few other technologies that, although not necessary, will increase one's satisfaction with using solar heating.
Advanced windows use a combination of double or triple glazings, low-emissivity coatings, argon or krypton gases, and transparent insulation. Selecting advanced windows and orienting most of them to face towards the equator can significantly reduce the annual heating load. Studies have shown that houses designed using such passive solar concepts can require less than half the heating energy of the same house using conventional windows with random window orientation. Proper design and selection of shading devices can also result in reduced cooling loads. A significant challenge for the next generation of modern dwellings is the integration of advanced window technologies, superior day lighting and passive solar heating for buildings in cold climates. New technology developments, in particular with advanced windows and airtight envelopes, make many older passive solar “rules-of-thumb” obsolete, and require the use of energy performance analysis tools.
The market for advanced windows in residential and light commercial applications continues to grow both in absolute number of units sold and relative share of the window sales. Out of about 5 million units annually sold in Canada, about 40% now incorporate low-emissivity coated glass. There has also been little growth since 1995 in the non-residential window market, with current total annual vision area of about 21.7 million square feet, of which 31% feature low-emissivity coated glass. Current interests focus on commercial envelope systems, including curtain walls, that are notoriously inefficient, and day lighting systems such as atrium glazing.
Transparent insulation comes in many forms, but it must be able to do the following:to allow sunlight or solar energy to pass through, while preventing heat from doing the same.
The structure and material type of transparent insulation sets it apart from conventional insulation and other building materials.Plastic is an example material type, while several common structures for transparent insulation are:
Advanced windows can be considered as an example of transparent insulation.
For most types of transparent insulation the daylight that passes through them is diffused making is difficult to see clearly through. Applications for transparent insulation include: greenhouses, passive solar heating,Trombe wall daylighting, privacy glazings, and flat plate solar collectors,
The Trombe wall is a building design concept that has been around for over 20 years. It has never gained wide acceptance but advances in transparent insulation technologies have improved its potential.