Maybe we rarely hear about Algae. But we just know it only in biology subject in the schools or collages. Algae are a large and diverse group of simple, typically autotrophicorganisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are currently excluded from being considered plants.
Though the prokaryoticCyanobacteria (commonly referred to as Blue-green Algae) were traditionally included as "Algae" in older textbooks, many modern sources regard this as outdated and restrict the term Algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group, as they do not include all the descendants of the last universal ancestor nor do they all descend from a common algal ancestor, although their chloroplasts seem to have a single origin.
Algae lack the various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some unicellular species rely entirely on external energy sources and have limited or no photosynthetic apparatus.
Nearly all algae have photosynthetic machinery ultimately derived from the Cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago.
Today, Algae is one of alternative energy that can be used for renewable fuel. Energy from Algae presents an opportunity you cannot afford to ignore. Deriving energy from algae is considered the Holy Grail of alternative energy. Algae, a third-generation biofuel feedstock, present one of the most exciting possibilities as a future solution to our energy problems, especially that of transportation fuel. In the last few years, activity in this field has been accelerating fast.
Why are algae so exciting from a renewable energy standpoint? For a number of reasons :
The yields of oil and fuels from algae are much higher (10-100 times) than competing energy crops
Algae can grow practically anywhere, thus ensuring that there is no competition with food crops.
Algae are excellent bio remediation agents - they have the potential to absorb massive amounts of CO2 and can play an important role in sewage and wastewater treatment.
Algae are the only feedstock that have the potential to completely replace world's consumption of transportation fuels.
Algae are already being used in a wide variety of industries and applications, and many newer applications are being discovered. Such a wide range of end-uses enable companies to produce both fuels and non-fuel products from the same algae feedstock
Algae can produce several fuel products, there are:
With the cost of energy skyrocketing, many people are turning to things like solar to shave their power bills. But you donate have to spend 10s of thousands of dollars to make a difference. Money reporter Stacy Johnson explains how little things can make a big difference.
The sun has produced energy for billions of years. Solar energy is the sun’s rays (solar radiation) that reach the earth.
Solar energy can be converted into other forms of energy, such as heat and electricity. In the 1830s, the British astronomer John Herschel used a solar thermal collector box (a device that absorbs sunlight to collect heat) to cook food during an expedition to Africa. Today, people use the sun's energy for lots of things.
Being an engineer, this got me thinking, so I did some research and found a number of useful resources. The most inspiring book was ‘Cooking with the Sun: How to Build and Use Solar Cookers’ by Beth and Dan Halacy. So, I decided to make a Solar Stove in June 2007, with this website as reference.
Otherwise, in my country, Indonesia, Dr. Muhammad Nurhuda, lecture from Physics Division of Brawijaya University had develop a Solar Stove too, but its different with mine. (Source: Kompas, 13 Maret 2008).
Why use a Solar Stove?
The heat energy produced by the sun is immense. In equatorial regions the solar radiation can exceed 1000 Watts/m2. That is equivalent to half the power of an electric kettle whenever there is good sunlight. It only takes 10 – 15 minutes to boil water on a solar stove. And it’s free, as long as you have clear blue skies! If not, you can boil it in 30 minutes. The material costs are about $10 per stove which with some sponsorship is feasible to raise, and they are fun to make.
Firewood, Kerosene and Health issues
The ‘Manual for solar box cookers’ published by Technology for Life, Finland quotes: -
"About 2000 million people, over one-third of the population of the world, are daily dependent on firewood as the source of their cooking and heating energy. They live in the tropics, in the most favourable areas for the use of solar energy. Every year the cutting of firewood results in the loss of 20,000 - 25,000 km2 of tropical forests (UNEP).
The use of solar cookers also brings with in important health benefits. Diseases spread through contaminated water cause 80% of the illnesses in the world (WHO). Heating water to the pasteurization temperature of about 60 0C destroys disease organisms. This temperature is easily achieved with solar cookers. Acute respiratory infections (ARI) are the cause of death for millions of children in the world each year. The large majority of these casualties occur in the developing countries as a result of polluted indoor air due to cooking over open fires in houses without chimneys or ventilation. This problem could be greatly reduced by using solar cookers, which are, of course, completely smokeless."
In Indonesia, kerosene was become primary needs for the source of cooking. Nowadays, the kerosene was rare and the government change it with natural gas. But, it's not renewable energy and it's still to expensive than buy kerosene stove and kerosene's.
How does a solar stove work
There are two basic methods of collecting enough heat from the sun to cook. These are commonly described as the ‘Solar Box Cooker’ and the ‘Solar Stove’.
Solar Box Cooker
The basic principle is to collect the heat by letting the sun light pass through a clear glass plate into a well-insulated enclosure. The light ‘trapped’ in the box and turns into heat when it is absorbed by the black cooking pot. The secret of a good Solar Box Cooker is to have good insulation with no air gaps and a good lid reflector to get the most light into the box. Cooking times are not that quick, but temperatures of 150 0C are possible.
Technology for Life, Finland has documented the Solar Box Cooker with great accuracy. For more information, click this link.
Solar Stove
The Solar Stove uses a parabolic reflector to focus the sunlight to one point. This produces the effect of a massive magnifying glass. With an accurate reflector it is possible to get ‘times 100’ magnification. The reflector is aligned to point at the sun, and then the black cooking pot is placed on a grill at the focal point. Being black the pot absorbs most of the sunlight and creates sufficient heat for cooking.
Precautions for use of solar stoves
Do not look at the reflection of the sun at any time. Once the stove is in alignment with the sun, and the pot is at the focal point, then there should be no light scatter. If there is ‘stray’ light then the stove may need adjustment such that all the reflected light hits the pot (this will improve your cooking as well).
When adjusting the angle of the grill use thick gloves as the grill can get very hot.
Materials required
The most important material in the stove is the reflective aluminum sheet. This I was fortunate to obtain courtesy of my ex. employer. The size of sheet was limited to 400 mm x 620mm as this fitted nicely in my suitcase. The aluminium is available from a number of suppliers, but the reflective qualities are important. I used 0.3 mm AnocoilÓ grade 710.33 which is 86% reflective and almost mirror quality.
The main enclosure is cut from 4 mm thick ‘Triple A’ plywood. An 8ft x 4ft sheet will make 21 stoves and only costs $5. A few other bits of wood are required to make the framework within the stove (sizes detailed below).
As the focal point gets very hot it is necessary to make the grill and grill support from metal. I used mild steel and painted it silver, but any metal will do.
Useful tools include: Drill, jigsaw, hacksaw, vice, wood saw, sharp ‘Stanley’ knife, tape measure, square, metal file and hammer.
Optional tools include: Grinder and welder.
Building the solar stove.
We split the work up into three sections. Manuel Reynaga was in charge of the metalwork, David Coe organized the lads (and one girl) in cutting the cardboard ribs, and I was in charge of the woodwork. We rotated the work, so they all had a go at each discipline. I was amazed how keen they all were to get things done. Once they saw the water boiling on our prototype they all wanted one!
1. Woodwork
I made up some templates for the sides and base, and cut them out using a 'jigsaw' power tool.The edges were filed flat. We then cut the frame parts to length and nailed the whole box together around the frame. See drawing WOOD for dimensions. Once the enclosure was assembled we made up the wooden SUPPORT at the base. This had the main purpose of holding the 16mm bar and grill in place. The support was nailed to the underside of the wooden box. To help align the stove with the sun we made a sundial by fixing a nail through the support at the edge parallel to the 16mm bar. By adjusting the stove to eliminate any 'shadow' of the nail it is easy to find the sun's location. See drawing GA for details.
2. Cardboard
Finding enough cardboard for 10 stoves was surprisingly difficult, but the 'Lord provided' just enough. The reflector profile is spherical with a radius of 0.7 m (equal to the square size of the enclosure). This gives an almost parabolic shape with a focal point at 0.35 m from the reflector. We used the 'wine box' principle of interlocking cardboard to create the required shape for the reflector to fit into. Ideally the box should be square (0.7 m x 0.7 m) but as our aluminium was not big enough we had to make it only 0.56 m wide by 0.7 m long. I designed the rib shapes on the computer, but it only takes a bit of Pythagoras to work out each radius. See drawing RIBS and RIBSX for details. Each rib is 0.07 m apart and 11 ribs are required to make the shape (including the two wooden ends). Each rib has a different radius depending on its location. I have designed a GENERIC profile that can be scaled up to any size of stove.
3. Metalwork
The hacksaw, drill and vice came in very handy. The three main items are the BAR, GRILL and PIN. The bar pushes into the wooden base and is located in place with the pin. The grill is fixed to the bar with an M5 x 20 screw with a wing nut and spring washer. This allows the grill to be secure but also adjustable as the sun changes height. The bar and grill were painted silver to reflect more light. See drawing GA for details.
4. Reflector
Once all the parts have been made they can be assembled into the box. The cardboard ribs should just drop in and sit flush with the base. If there are gaps under some of the ribs then it is probably because the slots in the ribs are not deep enough. Fitting the reflector is the final thing to do. We marked the reflector on 15 degree angles and then cut through with a very sharp knife leaving an area in the middle uncut. Take care of your fingers, we only had one accident! See REFLECTOR drawing for details. We then placed the reflector on top of the box and ribs and cut the edges to length. The reflector was then taped down around the edges, which produced an accurate focal point. We used shiny aluminium foil to tape the reflector in place. We found that the best method was to tape alternate edges first. This enabled us to push the other segments firmly on top of the first segments. It is worth spending time in getting each segment just right as this affects the focusing.
Maintenance and caring for your solar stove
When not in use, keep the stove in the dry. To store the unit in winter, remove the grill and grill support and turn upside down.
A dirty reflector will slow down the cooking times. Clean the reflector with a dry cloth or 'alcohol' if available.
Cooking tips Black pots work a lot better than silver pots. The pot needs to absorb as much light as possible and silver tends to reflect the light. Dull or 'matt' finishes absorb more light than 'shiny' surfaces.
Pots with close fitting lids keep the heat in and help the cooking process. Placing the stove in a sheltered area stops the wind from cooling the outside of the pot.
Generate cheap, green electricity from sunlight Solar electricity systems capture the sun's energy using photovoltaic (PV) cells. The cells convert the sunlight into electricity, which can be used to run household appliances and lighting. PV cells don't need direct sunlgiht to work - you can still generate some electricity on a cloudy day.
How do photovoltaic (PV) cells work?
The benefits of solar electricity
Is solar electricity suitable for my home?
Costs, savings and maintenance
Find out more
How do photovoltaic (PV) cells work? PV cells are panels you can attach to your roof or walls. Each cell is made from one or two layers of semiconducting material, usually silicon. When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced. PV cells come in a variety of shapes and colours, from grey "solar tiles" that look like roof tiles to panels and transparent cells that you can use on conservatories and glass. The strength of a PV cell is measured in kilowatt peak (kWp) - that's the amount of energy the cell generates in full sunlight.
The benefits of solar electricity
Cut your carbon footprint:solar electricity is green, renewables energy ans doesn't release any harmful carbon dioxide or other pollutants. A typical home PV system could save around 1.2 tonnes of carbon dioxide per year - that's almost 30 tonnes over its lifetime.
Cut your electricity bills: sunlight is free, so once you've paid for the initial installation your electricity costs will be greatly reduced. A typical home PV system can produce 50% of the electricity a household uses in a year.
Sell electricity back to the Grid:if your system is producing more electricity than you need, or when you can't use it, someone else can use it - and you could make a bit of money. Read more about selling electricity.
Store electricity for a cloudy day: if your home isn't connected to the national grid you can store excess electricity in batteries to use when you need it.
Is solar electricity suitable for my home? Solar panels are not light and your roof must be strong enough
To tell if solar electricity is right for you, there are a few key questions to consider:
Do you have a sunny place to put it? You'll need a roof or wall that faces within 90 degrees of south, and isn't overshadowed by trees or buildings. If the surface is in shadow for parts of the day, your system will generate less energy.
Is your roof strong enough? Solar panels are not light and the roof must be strong enough to take their weight, especially if the panel is placed on top of existing tiles. If in doubt, ask a construction expert or an installer.
Do you need planning permission? In England and Scotland, you don't need planning permission for most home solar electricity systems, as long as they're below a certain size - but you will if your home is a listed building, or is in a conservation area or World Heritage Site.
In Wales and Northern Ireland, you still need to get planning permission before installing a solar electricity system - though the legislation may soon change. To find out how to apply for permission, contact you local authority.
In Asia, especially in Indonesia, you still need to get planning permission from local goverment and PLN as goverment electric producer. But, I think it's no problem to install it without any planning permission for most home solar electricity systems.
Cost, savings and maintenance Costs for installing a solar electricity system vary a lot - an average system costs between £8,000 and £20,000, depending on its size and type. In general: the more electricity the system can generate, the more it costs but the more it could save solar tiles cost more than conventional panels panels built into a roof are more expensive than those that sit on top but, if you need major roof repairs, PV tiles can offset the cost if roof tiles Savings can be considerable - up to 1.2 tonnes of CO2 a year, and around £250 off your electricity bill*. A 2.5 kWp system could provide around half of a household's yearly electricity needs. Maintenance is generally small - you'll need to keep the panels relatively clean and make sure trees don't begin to overshadow them.
Find out more What's suitable for your home? To find renewable technologies to suit your home, try the Energy Saving Trust energy selector tool - coming soon
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The edges were filed flat. We then cut the frame parts to length and nailed the whole box together around the frame. See drawing 
The cardboard ribs should just drop in and sit flush with the base. If there are gaps under some of the ribs then it is probably because the slots in the ribs are not deep enough. Fitting the reflector is the final thing to do. We marked the reflector on 15 degree angles and then cut through with a very sharp knife leaving an area in the middle uncut. Take care of your fingers, we only had one accident! See 
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