- 250mm diameter.
- 350mm diameter.
- 450mm diameter.
- 550mm diameter.
Photovoltaic systems use cells to convert sunlight into electricity. PV cells can be made from different so-called semiconductor materials. Today, silicon is the most widely used material, but other, usually compound (made from two or more elements) semiconductors is also used. They are silent and non-polluting, utilise a source of energy that renews itself, and require no special training.
The solar thermal energy system generates and produces heat. This energy can be used to heat water or air in buildings or in many other applications.
Both use the irradiance of the sun even if the technology is quite different.
Solar Power A PV system consists of multiple components, including cells, mechanical and electrical connections and mountings and means of regulating and/or modifying the electrical output. Due to the low voltage of an individual solar cell (typically ca. 0.5V), several cells are combined into photovoltaic modules,which are in turn connected together into an array.
PV systems can be used for homes, offices, public buildings or remote sites where grid connection is either unavailable or too expensive. PV systems can be mounted on roofs or on building facades or operate as a stand-alone system. The innovative PV array technology and mounting systems means that PV can be retrofitted on existing roofs or easily incorporated as part of the building envelope at construction stage. Modern PV technology has advanced rapidly and PV is no longer restricted to square and flat panel arrays but can be curved, flexible and shaped to the building design.
“Grid connected” means that the system is connected to the electricity grid. Connection to the local electricity network allows any excess power produced to feed the electricity grid and to sell it to the utility. Such a PV system is designed to meet all or a portion of the daily energy needs. Typical on-grid applications are roof top systems on private houses.
The figure shows how electricity generated by solar cells in roof-mounted PV modules is transformed by an inverter into AC power suitable for export to the grid network. The householder/generator then has two choices: either to sell all the output to the local power utility (if a feed-in tariff is available) or to use the solar electricity to meet demand in the house itself, and then sell any surplus to the utility.
“Off-grid systems” have no connection to an electricity grid. Off-grid systems are contributing to rural electrification in many developing countries. PV is also used for many industrial applications where grid connection is not possible e.g. telecommunications, especially to link remote rural areas to the rest of the country.
Off-grid (stand-alone) systems use charge controllers instead of inverters and have a storage battery for supplying the electric energy when there is no sunlight e.g. during night hours.
Solar cells produce direct current. Most of the electrical devices we commonly use however, expect a standard AC power supply. An inverter takes the DC from the solar cells and creates a useable form of AC.
An inverter is moreover necessary to connect a PV system to the grid.
If a home or office requires more electricity than can be provided by the PV system, the balance is provided through the grid connection. The utility provides AC power to the owner at night and during times when the owner’s requirements exceed the capability of the PV system.
In many countries, the utility company purchases all PV electricity generated at a higher rate (feed-in-tariff) than the tariff applied for consumed electricity. In this case, a dedicated metering exists for “PV generation” and a second metering for “power taken from the grid”, applying each different tariffs.
FITs have been empirically proven to generate the fastest, lowest-cost deployment of renewable energy, and with this as a priority for climate protection and security of energy supply, not to mention job creation and competitiveness, FITs are the best vehicle for delivering these benefits.
The FIT system means that the pay-back time for PV is no longer several decades but several years instead.
The light of the sun consists both of direct light and indirect or diffuse light (which is the light that has been scattered by dust and water particles in the atmosphere). Photo voltaic cells not only use the direct component of the light, but also produce electricity when the sky is overcast. It is a common misconception that PV only operates in direct sunshine and is therefore not suitable for use in temperate climates. This is not correct: photo voltaic make use of diffuse solar radiation as well as direct sunlight.
When sunlight strikes a photo voltaic cell, direct current [DC] is generated. By putting an electric load across the cell, this current can be utilized. The amount of useful electricity generated by a PV module is proportional to the intensity of light energy, which falls onto the conversion area. The greater the available solar resource, the higher the electricity generation potential.
However, as the electrical output of a PV module is dependent on the intensity of the light to which it is exposed, it is certain that a PV module exposed to the sun at midday by clear sky, will produce maximum of its output electricity. You can thus indeed say that PV modules will tend to generate more electricity on bright days than when skies are overcast. Nevertheless, photo voltaic systems do not need to be in direct sunlight to work, so even on overcast days a PV module will be generating some electricity.
The electricity production of a PV system depends on external (environmental conditions) and internal (technology, layout of the system) parameters.
The efficiency of the PV module depends on:
The size of the PV system and its technology
The orientation of the PV module towards the sun. The optimal orientation for locations above the Ecuador is the south.
The tilt angle or inclination of the roof. For European countries, the average optima inclination is 30-35 degrees
The irradiance value on site
The climate zone.
Shadows on the modules (also if they appear only at certain times of day) reduce significantly the gain of the whole system and should be avoided.
The map below represents the yearly sum of global irradiation on a horizontal (inclined) surface. Alternatively the maps represent solar electricity [kWh] generated by a 1kWp system per year with horizontal (or inclined) modules.
In the light of decreasing solar electricity generation costs and increasing price for conventional electricity, solar power systems will equally become increasingly economic during the next few years. During the next 5-10 years, solar electricity will become cheaper (depending on location and peak hours) for private households than retail electricity.
A considerable advantage of solar electricity is that it is mainly produced around midday when conventional electricity is particularly expensive. Solar electricity largely replaces expensive peak-load electricity at preferential customer prices, which is why it would be wrong to compare it with cheap base-load electricity.
The energy source the solar production is replacing (coal, gas, hydro-electric, nuclear…)
The quantity of energy produced by the solar roof (depending on the roof’s location, orientation, inclination and shading)
The quantity of electricity needed to manufacture the photo voltaic system (modules, inverter, cables, etc.)
The “energy habits” of the solar roof owner.
How much CO2 will a solar roof save If your electricity comes from a coal fired power station, each kWh you use will release around 1.000 g of equivalent carbon (various greenhouse gases converted into “equivalent carbon units” for comparison). However, if your original electricity comes from a hydro-electric power station, it is producing much less carbon equivalent emissions (less than 10g).
A very important factor is the design of the system. If a system is wrongly designed (e.g. modules facing the south and 90degree inclination) the electricity output will be very low and therefore the system will not replace much conventional electricity.
So clearly the amount of CO2 you will be saving is very dependent on the source of the energy replaced. Next to CO2 savings, each m² of solar module installed will produce clean and sustainable home-made electricity.
Hence it is worthwhile producing solar energy not least because this makes us less dependent on energy imports but also because:
The fuel is free
It produces no noise, harmful emissions or polluting gases
PV systems are very safe and highly reliable
It brings electricity to remote rural areas
The energy pay-back time of a module is constantly decreasing
It creates thousands of jobs
It contributes to improving the security of Australia’s energy supply.
Most manufacturers in general propose performance guarantees on the modules after 20 years of 80% of the initial output power. On the electronic components and accessories (inverts), the guarantee usually does not exceed 10 years.
But this doesn’t mean that PV systems don’t produce energy after 20/25 years. Most PV systems installed more than 25 years ago, still produce energy today!
Most manufacturers indeed propose performance guarantees on modules of 20 and 25 years for 80% of the initial output power. On the electronic components and accessories (inverts), the guarantee usually does not exceed 5 to 10 years.
A considerable advantage of solar electricity is that it is mainly produced during the day when the demand is high and therefore electricity is particularly expensive. Another important characteristic is that PV is normally produced at the same site than demand; therefore, it is not necessary high investment on extending the electricity infrastructure.
In the long term, solar energy will be much cheaper than conventional energy. However, solar energy is already well on the way: whereas the costs for conventionally generated energy have constantly increased in recent years and – faced with finite resources – will continue to increase by a considerable extent, increasing mass production has enabled the cost of solar energy to drop by an average of 10% per year.
LEDs work on a totally different premise, similar to transistors or other electronics along those lines. There is no filament to burn out. They’re also a much more efficient light source, producing considerably more light per watt than a traditional bulb.
Most LEDs are about 2/10 of an inch in diameter and about 1/3 of an inch in length. Whereas typical household lamps require 120 volts, an LED uses just two or three volts. What’s more, typical household lamps are rated for 1,500 to 2,000 hours while LEDs can last 50,000 hours or more.
LED is a solid-state technology. This means there is no glass bulb, no pressurized gases, no mercury and no burning filament. In the traditional bulb, Heat was the main result while light stood as a mere by-product of electrifying the filament.
With LED technology, what you have is a circuit board and a computer chip. The properties of the chip create light that is generated and focused through a plastic diode to create light. Depending on the chip and materials used, different colours in the colour spectrum can be created.
Save money and energy by using LED bulbs. Generally, an LED consumes less than 0.1 watt to operate. This incredibly low consumption means you will save on your energy costs right from the start.
The typical LED bulb will last for 50,000 hours. This is over 10 Years of light from One Bulb used half the time. Compared to an incandescent bulb, which lasts 1,000 hours, a halogen bulb lasts 2,000 hours, and a compact fluorescent bulb may last up to 10,000 hours.
The extremely long life of an LED bulb will virtually eliminate your maintenance costs. There will be no need to change light bulbs throughout the year.
The solid state technology of an LED is very durable and can withstand high levels of shock and vibration. Its able to operate in extreme temperatures cold, or hot. (-35C to 80C).
LED convert almost all the energy used into the light output, making them a highly efficient light source. LED generate less than 30% of the heat of traditional lighting technologies. With minimal heat generated, LED are safe to the touch and do not produce any harmful UV rays.
LED are environmentally friendly, they are made from non-toxic materials unlike fluorescent which contain Mercury. For more on what LED are made from.
The bottom line is that LED’s are easier and safer to use than all previous lighting technologies. Plus, LEDs will save you money by consuming less power, lasting much longer, and generating much less heat, which in turn combine to result in lower climate control costs.
Broadly you can say you have a product for every application from LED Downlights, Bulbs, Ceiling Lights, Patio Lights, Industrial Lights etc.
Also, your solar water heater can work fine in cloudy days. However, in case of very cloudy days or extended period of cloudy days, the gas or electric booster that comes with your system will automatically kick in. This entails that you and your family will have 24-hours access to hot water, irrespective of the weather condition.
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