Appropriate Technology - PDF Document
Appropriate Technology
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Permaculture Resource Book Module 12.Appropriate Technology Module No 12 . Appropriate Technology
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New technology is constantly being invented to improve life. A good idea is an idea that helps people to evolve and helps societies to become better and more sustainable. However, sometimes technology has negative impacts on people and the environment, and often new technology is expensive to buy and difficult to maintain, for example: • Cars are tools for transportation, but they use oil and petrol which is taken from the earth, this supply will not last long and cars are causing pollution problems all over the world • Electricity from generators also uses fuel and causes pollution • Tractors can plough fields quickly, but they are difficult and expensive to maintain, and they cannot be used on sloped land A lot of technology that helps make life easier is actually helping to create a huge problem that the whole world now faces, this problem is called “global warming”. Too much carbon dioxide (CO2) in the atmosphere is altering the earths natural cooling cycle. Ice and snow is slowly melting in some places and the temperatures are slowly rising. This situation will only get worse unless changes are made all over the world and more sustainable technologies are used. Even small countries have continuous needs. Because of this, the best technologies to use are sustainable technologies that suits the needs of the local people. This type of technology is called “Appropriate Technology”. Appropriate technology has certain characteristics, such as: • It is easy to understand • It can be sold, owned and maintained • It reduces electric use, labour, fuel use and other energy use • It uses natural, environmentally friendly materials and reusable energy Some examples of appropriate technology: • Diesel vehicles and motors which are run using coconut oil • Electricity which is created using energy from the sun, wind, water and even manure • Using animals for labour, such as buffalo, cows and horses for transportation, field work and other labour, instead of only being kept for consumption M od ule 1 2 : A p p rop ri at e Te ch n olog y 297
Clay Ovens and Stoves Stoves and ovens made from clay are a simple technology, which can be easily made and will provide many benefits, such as: • Conserves firewood, which will save money, labour and helps protect the environment for the future • Produces less smoke, which helps reduce pollution and health problems • Can use alternative fuel, such as rice husks, coffee husks, sawdust or charcoal bricks, as a replacement for wood Clay Stoves clay stove cross section Clay stoves are commonly used in many regions. They are very simple to use and will conserve firewood because the clay helps to provide heat for cooking. Clay stoves are made from clay (75%), dried cow manure (25%), small amount of cement (5%), and a little water to make the mixture moist but not wet. a clay stove with 2 burners and a chimney Clay Ovens Clay ovens will work better than clay stoves. They can be made in many different shapes, small or large, and can also function as a heater or as a stove. These ovens can also have a chimney to draw smoke out of the kitchen to make the air safer for peoples health. Clay ovens are also made from clay, dried cow manure and a small amount of cement. stove cross section Method 1 Use clay bricks for the bottom and sides. Cover them with a thick render made from clay (75%), dried cow manure (25%) and cement (5%, if available). Use wire to shape a frame for the oven top. Make 2 or 3 holes in the center of the wire, about 10 cm wide for cooking pots. The top should be flat, so the cooking pots can be placed on top flat and not slanted. Make one more hole at the back of the oven for a pipe / bamboo chimney, to let smoke out. Cover the wire with the clay mixture, use a layer of about 10 cm thick so the wire is in the middle. Make a door at the front that is large enough, it must be 10 cm thick and should fit very well to stop smoke and heat from escaping. Make a round thin metal sleeve to hold the bottom of the chimney. Place a pipe or bamboo into the prepared hole and use clay to seal all the gaps between the metal and the chimney pipe. Make a lid for the cooking pot hole to cover the holes when cooking pots are not being used. These lids should fit tightly to stop smoke and heat from escaping. Method 2 Follow the same steps as method 1, but use a wire frame mold to shape the whole oven frame. Make sure that the thickness of the oven is 10 cm or more. 298Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
Charcoal Brick Cooking Fuel Firewood is expensive and takes hard work to collect. Firewood also creates a lot of smoke. Charcoal bricks is a very good cooking fuel that lasts a long time and produces only a little smoke. Charcoal bricks can be made easily using local materials. Making Charcoal Bricks To make charcoal bricks, use the following steps: • Cut the bottom off a drum. Turn it over and cut a small circle, 20 cm wide, in the middle of the other end. Make sure any sharp edges are hit down • Fill the drum with fresh bamboo leaves, thin split bamboo (not dry bamboo), coconut shells and husks, coffee husks, rice husks and leaves (bamboo leaves are best). Burn these materials slowly and stir the fire occasionally with a wooden pole through the hole in the top of the drum. Occasionally add some splashes of water to slow the burning process. Add more materials if available. When the material has all burned and turned into black pieces of charcoal, put the fire out with water. The black charcoal will be left at the bottom 1 2 • Make a glue paste. Crush some fresh cassava root and take the sap that forms. Add some water to make a thick glue paste 3 Or, crush some cassava stems (without the bark) and mix with water. Leave the mixture to settle. This mixture will separate into liquid at the top and a thick paste at the bottom. Pour off the liquid until only the paste remains 4 2 •Combine the black charcoal with this cassava glue / paste (90 to 95% charcoal and 5 to 10% cassava paste. Put this mixture into brick molds and leave in the sun until dry 5 Using Charcoal Bricks Charcoal bricks can be used to cook with open fires, clay stoves or clay ovens. The bricks will burn slowly and produce a constant heat. Start a small fire with wood sticks and add the charcoal bricks when the fire is lit. The bricks will slowly burn themselves. Add some more wood sticks if you need to increase the heat, and add more charcoal bricks as needed. M od ule 1 2 : A p p rop ri at e Te ch n olog y 299
Drum Ovens An old drum can be used to make a simple, large oven. The materials needed are sand, rocks and banana leaves. This method uses less wood to cook the same amount of food as a cooking fire. Also, by using a drum oven to cook, the food will contain more nutrients compared to boiling or frying food. How to cook: • Cut off the top of a drum. Clean the inside with detergent and water. Leave in the sun to dry • Fill the drum half way with sand • Collect some hand sized rocks. Make a fast fire with dried palm leaves, bamboo leaves, small wood sticks and other materials, to burn the rocks (don’t use rocks from the river because they could explode!) • When the rocks are very hot, use a shovel to put to layers of rocks on top of the sand in the drum. Then put 2 layers of fresh banana leaves on top of the rocks. Place food on top of the banana leaves. Meat, fish, cassava, sweet potato, potatoes, corn, bananas, eggplant, mushroom, pumpkins, yams, carrots and more can be cooked. Then add 2 more layers of banana leaves to cover the food, and 2 more layers of hot rocks on top of the banana leaves. Cover the top with any material, like metal, plywood or an old cloth. Leave for 2 hours • Remove the cover, rocks and banana leaves, and some tasty food is ready to be eaten! SMART IDEAS! • Instead of cutting the top off the drum, just cut the drum in half. In this way you will have 2 ovens! • This same method of cooking can be used by digging a hole in the ground. In areas with sandy soil, this method will be much more simple to use Sawdust Stoves This idea was taken from Lik Lik Buk, a guidebook from Papua New Guinea. This stove uses sawdust as cooking fuel. The stove may also work with dried rice husks or coffee husks, but these fuels should be tested first to see which materials work best. This method of cooking will produce little or no smoke. You can make and use a cement stove. To make a cement stove, you will need materials such as a mold, which could be an old bucket or can, some wire, fine sand and cement, about 1/4 bag of cement for one stove. 300Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
The following steps can be used to make the stove: 1. Make a small hole in the bucket, about 3 cm from the bottom of the bucket 2. Mold wire so that it fits inside the bucket, but slightly smaller so it is not touching the sides and bottom of the bucket. The wire should be 2 cm below the top of the bucket. Don’t let the wire cover the hole at the bottom of the bucket 3. Mix the cement and sand, about 1 part cement to 3 parts sand. This should be a fairly dry mix. Put about 2 cm of cement into the bucket (at the bottom), then place the wire mold into the bucket so it sits on top of the wet cement. Place a tin can in the bucket. Put a bamboo or wood through the small hole at the bottom of the bucket, and position it so that it is just touching the tin can. Place a rock into the tin can to prevent it from moving. Carefully fill the space between the bucket and tin can with the cement mixture. Fill it evenly up to the top of the bucket. The wire mold functions as the frame for the cement stove 4. Leave for 1 hour, then carefully make 2 cuts in the top of the cement, about 1 cm deep and 2 cm wide. These cuts will provide important air flow when cooking and are essential for the stove to work 5. When the cement has dried, carefully remove the tin can by slowly twisting and pulling it. Also remove the bamboo at the bottom of the stove 6. Put the bucket of cement in a dry, dark place and leave for 2 days 7. To remove the bucket, gently tap the sides of the bucket, then turn the bucket over and shake it until the stove slides out. Be careful not to let the stove fall and crack. Cover the stove with a damp cloth and keep it moist for one week to preserve the cement. After this time, the oven is ready to be used! How to use cement and sawdust stoves: 1. Take 2 pieces of bamboo. Place one piece in the center of the stove in a vertical (straight up) position and place the other piece through the hole so that it is touching the first piece of bamboo 2. Pour sawdust into the stove from the top until the stove is full and tightly packed 3. Carefully twist and remove both pieces of bamboo without moving the sawdust, so the stove has an ‘L’ shaped tunnel inside 4. To light the stove, take a thick piece of dry wood and dip it in kerosene, then put it in the bottom hole of the stove, light a match and drop it into the stove from the top hole 5. The sawdust will slowly burn. Once the sawdust in the middle is bright red, the piece of wood can be removed. The stove will provide constant heat for 2 hours. If more heat is required, place another stick into the stove M od ule 1 2 : A p p rop ri at e Te ch n olog y 301
Tin Metal Stoves Tin metal stoves use rice husks or coffee husks to burn instead of firewood. These stoves are designed so that air enter through the bottom and keeps the husks burning continuously. Tin metal stoves last a long time and a blacksmith can easily make them. Gas Stoves Gas stoves are slightly more expensive than firewood stoves because you must buy the stove and gas bottle, however the benefits received are more than worth it. Using these stoves is much easier, faster and cleaner than using firewood stoves. They do not produce any smoke. Solar Cookers Solar cookers use heat from the sun to heat food or cook it slowly. Food can be cooked first on a stove or fire until it is ready and then it can be kept in the solar cooker to keep it hot. Tin foil and glass are used to reflect and catch sunlight and heat, and insulating materials (such as coconut fibre or kapok) or wood painted black is used to store the heat. Solar cookers are good for cooking soups, rice, corn and more. Use materials that are inexpensive and easy to find. The cookers can be a box shaped closed cooker or a simple open cooker. 302Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
Solar Driers Solar driers can be used to dry fish, meat, vegetables and fruits, and it will also keep food protected from insects and other animals. This tool will dry food much faster, for example drying fish takes 1 week normally, but with a solar drier it only takes 2 days. Solar driers reduce food waste, especially during harvest time, when there is sometimes too much food to be eaten or sold. The nutrients in the food will stay in the food, and dried foods can easily be traded or sold. There are many different types of solar driers, but we will only explain 2 of these types. Plastic Solar Driers Plastic solar driers use a very simple design. The frame is made of wood and is wrapped tightly in clear plastic. Inside are shelves made with a wooden frame and a base of insect wire. The wooden legs of the shelves are put into tins filled with water to prevent ants from damaging the food. The back of the drier can be left open to make access easier. At the bottom, front side of the drier, an extra section can be added to catch hot air. Wrap the top of this section with clear plastic. Hot air will be collected inside and will rise up to the top of the drier, because hot air always rises, and then leave through the insect wire at the top of the drier. This method is called ventilation, which will help to speed up the drying process. Wood and Glass Solar Driers This type of drier will work well to quickly dry food materials, such as: • Large fish, in 3 days • Small fish, in 1 day • Vegetables, in 1 day • Meat, in 3 days (for meat that has been cut into slices 3 cm thick) This type of solar drier is more expensive to make, but it will dry food faster and will last longer than plastic solar driers. This type of solar drier is also very easy to clean. If these driers are maintained well they will last up to 5 years, or more. Just like plastic solar driers, this tool works by using ventilation / air flow. M od ule 1 2 : A p p rop ri at e Te ch n olog y 303
Natural Coolers If meat, vegetables and fruits are cooled, they will last much longer. For some remote areas, refrigerators are too expensive and use a lot of electricity to work. The Coolgardie safe, which was invented in Coolgardie, a town in Western Australia, is a simple way to store food and keep it cold, while preventing insects and animals from touching the food. The safe is a wooden box that has shelves inside to place food on. This box can be as big or as small as you need. One side opens like a door, and all of the sides have insect screens with wooden edges. The insect screen will allow wind to blow through but stop animals and insects from entering. On top of the box place a tray that is filled with water. Attach a large piece of hessian to the tray and position it so that it hangs down over 2 sides of the box. The hessian / cloth draws water from the tray down to the sides. Wind blows the wet hessian and this keeps the food inside the box cold. Add water to the tray as needed. The Coolgardie safe can be hung or placed on a stand. The safe should always be placed outside so that it receives wind. Clay Pots Clay pots are very good for storing food, especially vegetables and fruits. In this way the food will stay fresh for a few days longer. Place food in a clay pot and cover it with a damp cloth. Make sure the cloth stays wet and keep the clay pot out of the sun. Or, use 2 clay pots, on clay pot inside of another clay pot. Put a layer of damp sand in between the two pots. Make sure the sand stays moist and cover the pots with a wet cloth. Keep out of the sun. 304Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
Electricity The cost of electricity is expensive and it will only get more expensive, so conserving electricity is very important. Conserving energy is something that should be done by people all over the world. micro- hydro regulator wind battery invertor Natural electricity production is much better for the future. It also produces very little pollution and can be used by all levels of society, from individual needs to public needs. solar natural energy sources & systems Hydro-electric Systems Hydro-electric systems use flowing water to create electricity. Water from rivers, dams or lakes run through a pipe that goes down hill, the water then causes a wheel to spin around in the hydro-electric unit, which turns a turbine and creates electricity. This electricity is then stored in batteries until it is used. Hydro-electric systems can be many different sizes, from micro-hydro systems which supply electricity to a few houses or a village, to very large hydro- electric systems that run from large lakes or dams and can supply electricity to an entire city or province. Using small hydro-electric systems will provide many benefits: • They produce a small but continuous supply of electricity • They are more environmentally friendly compared to large hydro-electric systems, both in setting up and in long term impacts • Maintenance is easier compared to large hydro- electric systems or other systems, like solar systems • They use smaller storage batteries larger micro- hydro systems Biogas Systems A biogas system collects methane gas, which is a flammable gas used for cooking, running gas lights, running internal combustion machines and used to create electricity. Methane gas is naturally created when animal manure, human manure, rice husks, leaves, water plants and grasses decompose. In a biogas system, these materials are collected and placed in a biogas tank, so that the gas which is created becomes trapped in the tank and can be used. New materials can continuously be added to the tank, and the old materials can be taken out and used as a very high quality fertilizer. M od ule 1 2 : A p p rop ri at e Te ch n olog y 305
There are many benefits which can be achieved by using this system: • The gas and electricity produced comes from available and inexpensive sources gas pipe tank inlet generator outlet gas • Gas replaces the need for firewood, which helps to reduce smoke pollution gas cooker manure • The manure and other materials used will continue to store nutrients needed by plants, in fact because of the gas producing process, the nutrient levels will increase. After these materials have decomposed and produce methane gas, the materials can be reused to make compost or used directly on crops as fertilizer. However, be careful because this creates a very strong fertilizer liquid stirrer overflow tank • Almost all bad bacteria in the manure, which can spread disease, are killed in the biogas tank so this will reduce the chances of disease spreading to humans and animals This system is already being used in many countries and is a very good technology. There are many different designs for biogas systems, depending on the type of materials available, money and what the system will be used for. Some basic facts about biogas systems: • 1 m3 (1 m x 1 m x 1 m) of methane gas provides: Gas to cook 3 family meals, or 6 hours of light from a light bulb, or 700 ml of fuel to run a 2-horsepower generator for 2 hours, or 1.25 kw of electricity • 1.5 m3 of tank size per person will provide enough methane gas for ever day needs (or, 15 m3 for 10 people) Biogas systems are anaerobic (no oxygen), so they must be made air tight and water tight. Maintenance of the system includes maintaining water levels, pH levels, temperature, material input mixtures, protection from harmful materials and tank stirring management. To create and maintain a biogas system, research and technical knowledge are needed, this information can be found through books, the internet or NGOs actively working with this system. This will bring better skills and knowledge, as well as the many benefits which can be achieved by using biogas systems. 306Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
Solar Systems A solar system uses sunlight and solar panels to create electricity. The solar panels must be placed so they receive a lot of direct sunlight, not shaded by buildings, trees and so on. However, if the solar panels become too hot they will not work well. This will happen if the panels are touching metal or tin roofs. If possible, keep them away from tin roofs or put lots of insulation (old material, cardboard, bamboo, wood and so on) between the roof and panel. Solar systems are already being used in many countries. These systems will provide electricity anywhere, and with the right knowledge they are easy to set up. However, it is also important to have knowledge of how to maintain and operate them properly, the batteries especially have to be looked after well, because if they are maintained or used incorrectly they can break very easily. These systems are expensive, but they will provide environmentally friendly electricity for communities. Wind Systems Wind can also be used for making electricity. Wind generators use propellers which turn when the wind blows, this causes other components to also turn which transmits power to a water pump or generator. The energy which is created is then stored in large batteries used to provide electricity. Wind generators come in many sizes, from small generators which can create enough electricity for a household, to very large generators which can create enough electricity for many houses. In some countries, many large wind generators are made and placed in areas where the wind is strong enough to create a lot of electricity. These areas are called wind farms. In the future, large wind farms could provide electricity for entire cities, replacing diesel generators. To make this possible will require working with the government and businesses. Wind farms take a lot of money to build, but they are more sustainable and will save money in the future. The wind farms could be part of a national system and can be combined with other natural electricity sources. M od ule 1 2 : A p p rop ri at e Te ch n olog y 307
Oil Fuel Cars, trucks, motor bikes and other vehicles create a lot of pollution problems in the world today. The pollution starts from the process of mining to access the fuel, and continues until the fuel is used to run motor vehicles. New technologies have been created to reduce these problems, such as electric cars and hydrogen cars. There are also other more simple technologies, such as using coconut oil to run diesel machines, this will be explained briefly in this manual. Coconut Oil for Diesel Machines Cars and diesel machines can be run on high quality coconut oil. With some slight changes and an oil heater, cars can also be run on used frying oil! Information about this technology and more can be found in books and on the internet. Coconut oil for diesel machines and cars is the simplest and most appropriate method to use, some research and testing about this method has already been undertaken. Coconut oil can be used for all diesel machines, including cars, trucks, hand tractors, rice mills, small generators, pumps and more. The coconut oil used must be very high quality, because if not it could destroy the machine. The coconut oil from the markets cannot be used, because it is usually very low quality. To use it, combine 20 parts coconut oil to 1 part kerosene (5%). This will help make the liquid thinner. In cold areas, combine 10 parts coconut oil to 1 part kerosene (10%). This method has been successful in Bouganville, Papua New Guinea, for many years and is now being used in Fiji and Thailand. Water Pumps Machine water pumps are commonly used but they are expensive and need fuel to operate. Following are some example of simple water pumps which do not need fuel to operate and are much easier to maintain. Ram Pumps A ram pump uses water pressure created by gravity to flow water a long way uphill. Water from a spring or other water source can be collected in a small tank / container. The water must be clean, because if it is dirty it will cause problems. The water then flows downwards through a pipe, which is usually 10-20 meters long. The presser is created as the water flows downwards. The water flows into the pump, creating air pressure and pumping water through smaller pipes back uphill. Water can be pumped through smaller pipes as far as a few hundred meters. The water can then be flowed to water storage containers. By using this type of pump, water can be flowed in large amounts, and if the water source is constant, the water can be flowed all year long. This tool is a great economical solution for water supply problems. 308Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
Foot Pumps and Treadle Pumps These pumps can be used to pump water from a bore or well, and can also be used to pump water from a spring or river. These pumps use 2 boards which are attached to 2 cylinders below them. To operate the pump takes a similar movement as someone walking, moving the boards up and down with their feet. Air pressure is created and sucks the water up through a pipe into the cylinders and out the top, to then be directed to wherever you need it, like for house or garden needs. It is very similar to a hand pump, but more water can be moved for less effort. Solar Power Water Pumps Solar powered water pumps are used to add oxygen to ponds. The pump is run by using a small solar panel which creates electricity for the pump. These are great for fishponds and can also be used in water cleaning systems. Windmills Windmills use wind power to pump water from underground to above ground, to be used for house needs or irrigation. A windmill is like a giant fan. The wind turns the blades of the windmill, which as they turn will force a piston to move up and down, sucking water to above ground through an underground pipe. Elevated Water Storage Water can first be moved into an elevated tank, and then run through pipes to where the water is needed. To move water into an elevated tank, take water straight from a roof using bamboo water collection, use a treadle or ram pump, or any other type of pump. M od ule 1 2 : A p p rop ri at e Te ch n olog y 309
Other Simple Tools Pedal Powered Grinders A simple but effective technology, a grinder that can be used to grind corn, rice, nuts and more. This grinder is connected to a bicycle, and the bike chain, which would normally turn the bike wheel, is attached to a cog which spins the grinder. This is much easier than pounding corn and much cheaper than using a petrol grinder. Oil Press An oil press is a tool used for extracting oil from seeds, nuts and other plant materials which produce oil, like coconut, candlenut and avocado. The oil that is produced is of high quality and it will greatly improve nutrition, especially for children, or it can be sold or traded. Good quality organic oils are a possible export market. Using the Internet The internet is one of the most important technologies for the future. The internet contains large amount of information which is useful for developing a sustainable future. With the internet, we will be able to share technologies and information with partner groups from all over the world. 310Pe rmacult ure , S olut i on s for S ust ai n able l i fe st yle s
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