Appropriate technologies find many applications in building and construction, agriculture, water and sanitation, energy generation and uses, transportation, health care, food preparation and storage, information and communication technologies, as well as finance.
In order to increase the efficiency of a great number of city services (efficient water provisioning, efficient electricity provisioning, easy traffic flow, water drainage, decreased spread of disease with epidemics, etc.), the city itself must first be built correctly. In the developing world, many cities are expanding rapidly and new ones are being built. Looking into the cities design in advance is a must for every developing nation.
and/or other green building materials could be considered appropriate earth building technology for much of the developing world, as they make use of materials which are widely available locally and are thus relatively inexpensive.
The local context must be considered as, for example, mudbrick may not be durable in a high rainfall area (although a large roof overhang and cement stabilisation can be used to correct for this), and, if the materials are not readily available, the method may be inappropriate. Other forms of natural building may be considered appropriate technology, though in many cases the emphasis is on sustainability and self-sufficiency rather than affordability or suitability. As such, many buildings are also built to function as autonomous buildings (e.g., earthships). One example of an organisation that applies appropriate earthbuilding techniques would be Builders Without Borders.
The building structure must also be considered. Cost-effectiveness is an important issue in projects based around appropriate technology, and one of the most efficient designs herein is the public housing approach. This approach lets everyone have their own Condominium|sleeping/recreation space, yet incorporate communal spaces such as mess halls, latrines, and public showers.
In addition, to decrease costs of operation (heating, cooling, etc.) techniques as Earth sheltering and Trombe walls are often incorporated.
Organizations as Architecture for Humanity also follows principles consistent with appropriate technology, aiming to serve the needs of poor and disaster-affected people.
Natural ventilation can be created by providing vents in the upper level of a building to allow warm air to rise by convection and escape to the outside, while cooler air is drawn in through vents at the lower level.
Electrical powered fans (e.g., ceiling fans) allow efficient cooling, at a far lower electricity consumption as airconditioning systems.
A windcatcher (Badgir; بادگیر) is a traditional Persianarchitectural device used for many centuries to create natural ventilation in buildings. It is not known who first invented the windcatcher, but it still can be seen in many countries today. Windcatchers come in various designs, such as the uni-directional, bi-directional, and multi-directional.
A passive down-draft cooltower may be used in a hot, arid climate to provide a sustainable way to provide air conditioning. Water is allowed to evaporate at the top of a tower, either by using evaporative cooling pads or by spraying water. Evaporation cools the incoming air, causing a downdraft of cool air that will bring down the temperature inside the building.
Agriculture
Appropriate technology has been applied extensively to improve agricultural production in developing countries. In the United States, the National Center for Appropriate Technology operates ATTRA (attra.ncat.org), a national sustainable agriculture assistance program.
The focus of discussion and research regarding technology adoption is the small scale farm, because it accounts for the majority of the planet's agricultural output.[1] The ethical question that emerges in the research is how much to focus on increasing the productivity of a nation's agricultural output and how much to address food insecurity in the population, including among farmers themselves. This issue of framing is significant because if countries are producing enough food for their populations, yet people are still not getting adequate amounts of food or proper nutrition, it is a problem of availability and distribution rather than production. It is possible for countries to have the agricultural capabilities to be completely self-supportive, but still have many food-insecure citizens. India is an example of this situation. The opposite can also be true; as of 2012, neither Hong Kong nor Singapore had the internal capability to sustainably feed their respective populations, yet they had much better rates of food-security than India.[1] A problem can arise when research focuses solely on advancements in production, ignoring the problem of food-insecurity in these communities.
Food insecurity is more than just a matter of increasing farm production: it is also about farm household income, location, amount of debt, and level of education.[1] Rural and impoverished communities are disproportionately and adversely affected by inequitable distribution of food and resources.[1] Increasing food production and output will not make distributing food easier or more equitable. Confronting these more difficult issues is the future of the sector's discussions and actions.[1]
Hand-operated, reciprocating, positive displacement, water pump in Košice-Tahanovce, Slovakia (walking beam pump).
As of 2006, waterborne diseases are estimated to cause 1.8 million deaths each year while about 1.1 billion people lack proper drinking water.[2]
Water generally needs treatment before use, depending on the source and the intended use (with high standards required for drinking water). The quality of water from household connections and community water points in low-income countries is not reliably safe for direct human consumption. Water extracted directly from surface waters and open hand-dug shallow wells nearly always requires treatment.
Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.
The most reliable way to kill microbial pathogenic agents is to heat water to a rolling boil.[3] Other techniques, such as varying forms of filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of waterborne disease among users in low-income countries.
Over the past decade, an increasing number of field-based studies have been undertaken to determine the success of POU measures in reducing waterborne disease. The ability of POU options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest.
The current priority of the proponents of POU treatment is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years.
On the other hand, small-scale water treatment is reaching increasing fractions of the population in low-income countries, particularly in South and Southeast Asia, in the form of water treatment kiosks (also known as water refill stations or packaged water producers). While quality control and quality assurance in such locations may be variable, sophisticated technology (such as multi-stage particle filtration, UV irradiation, ozonation, and membrane filtration) is applied with increasing frequency. Such microenterprises are able to vend water at extremely low prices, with increasing government regulation. Initial assessments of vended water quality are encouraging.
Whether applied at the household or community level, some examples of specific treatment processes include:
Porous ceramic filtration, using either clay or diatomaceous earth, and oriented as either cylinder, pot, or disk, with gravity-fed or siphon-driven delivery systems. Silver is frequently added to provide antimicrobial enhancement
Chemical flocculation, using either commercially produced iron or aluminum salts or the crushed seeds of certain plants, such as Moringa oleifera. Recent work has shown even table salt (NaCl) is effective at removing high-activity clays for solar water disinfection.[4]
Rainwater harvesting systems with an appropriate method of storage, especially in areas with significant dry seasons.
Fog collection, which is suitable for areas which experience fog even when there is little rain.
Air wells, a structure or device designed to promote the condensation of atmospheric moisture.
Handpumps and treadle pumps are generally only an option in areas is located at a relatively shallow depth (e.g., 10 m). The Flexi-Pipe Pump is a notable exception to this (up to 25 meters). For deeper aquifers (<10 m), The Rope pump and submersible pumps placed inside a well can be used. Treadle pumps for household irrigation are now being distributed on a widespread basis in developing countries. The principle of Village Level Operation and Maintenance is important with handpumps, but may be difficult in application.
Condensation bags and condensation pits can be an appropriate technology to get water, yet yields are low and are (for the amount of water obtained), labour-intensive. Still, it may be a good (very cheap) solution for certain desperate communities.
The hippo water roller and Q-drum allow more water to be carried, with less effort and could thus be a good alternative for ethnic communities who do not wish to give up water gathering from remote locations, assuming low topographic relief.
The roundabout playpump, developed and used in southern Africa, harnesses the energy of children at play to pump water.
The ideas of appropriate technology influenced the provision of sanitation systems for many years. However, since about the early 2000s there has been a departure from a focus on simplistic 'one-size-fits-all' sanitation systems.[7][8] As conditions vary, sanitation systems also need to vary to meet the needs of the users and other stakeholders.[8]
Technologies for sanitation provision, such as toilets, are important but only one piece of the puzzle. Sanitation needs to be regarded as a system that includes technical and non-technical aspects, such as behavior change and management as well as political aspects – the enabling environment.[9] The overall aim should be to achieve a sustainable sanitation system. One option of achieving that aim can be the ecological sanitation approach which focuses on safe reuse of excreta.
It is impossible to name all possible sanitation technologies that may fall under the category of "appropriate technologies" but some common systems which might be considered to be "appropriate" include:
Dry toilets as they save on flushing water and may allow the nutrients of the excreta to be reused in agriculture (e.g., for fertilising crops). Two examples of dry toilets are composting toilets and urine-diverting dry toilets.
The SanPlat is a simple plate that can be used to cover the hole in the ground of pit latrines making them potentially more easy to clean and maintain.[10][11]
The Arborloo which is a very simple low-cost type of composting toilet suitable for rural areas.
The term soft energy technology was coined by Amory Lovins to describe "appropriate" renewable energy.[12] "Appropriate" energy technologies are especially suitable for isolated and/or small scale energy needs. Electricity can be provided from:
Bioalcohols as bioethanol, biomethanol and biobutanol. The first two require minor modifications to allow them to be used in conventional gasoline engines. The third requires no modifications at all.
Vegetable oils which can be used only in internal combustion (Diesel) engines. Biofuels are locally available in many developing countries and can be cheaper than fossil fuels.
Biogas is another potential source of energy, particularly where there is an abundant supply of wasteorganic matter. A generator (running on biofuels) can be run more efficiently if combined with batteries and an inverter; this adds significantly to capital cost but reduces running cost, and can potentially make this a much cheaper option than the solar, wind and micro-hydro options.
Biochar is another similar energy source which can be obtained through charring of certain types of organic material (e.g., hazelnut shells, bamboo, chicken manure, etc.) in a pyrolysis unit.[15] A similar energy source is terra preta nova.
Finally, urine can also be used as a basis to generate hydrogen (which is an energy carrier). Using urine, hydrogen production is 332% more energy efficient than using water.[16]
Electricity distribution could be improved so to make use of a more structured electricity line arrangement and universal AC power plugs and sockets (e.g., the CEE 7/7 plug). In addition, a universal system of electricity provisioning (e.g., universal voltage, frequency, ampère; e.g., 230V with 50Hz), as well as perhaps a better mains power system (e.g., through the use of special systems as perfected single-wire earth returns; e.g., Tunisia's MALT-system, which features low costs and easy placement)[17][18]
Electricity storage (which is required for autonomous energy systems) can be provided through appropriate technology solutions as deep-cycle and car-batteries (intermediate technology), long duration flywheels, electrochemical capacitors, compressed air energy storage (CAES), liquid nitrogen and pumped hydro.[19] Many solutions for the developing world are sold as a single package, containing a (micro) electricity generation power plant and energy storage. Such packages are called remote-area power supply
LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps.
Compact fluorescent lamps (as well as regular fluorescent lamps and LED-lightbulbs) can also be used as appropriate technology. Although they are less environmentally friendly than LED-lights, they are cheaper and still feature relative high efficiency (compared to incandescent lamps).
The Safe bottle lamp is a safer kerosene lamp designed in Sri Lanka. Lamps as these allow relative long, mobile, lighting. The safety comes from a secure screw-on metal lid, and two flat sides which prevent it from rolling if knocked over. An alternative to fuel or oil-based lanterns is the Uday lantern, developed by Philips as part of its Lighting Africa project (sponsored by the World Bank Group).[21]
The Faraday flashlight is an LED flashlight which operates on a capacitor. Recharging can be done by manual winching or by shaking, hereby avoiding the need of any supplementary electrical system.
HID-lamps finally can be used for lighting operations where regular LED-lighting or other lamps will not suffice. Examples are car headlights. Due to their high efficiency, they are quite environmental, yet costly, and they still require polluting materials in their production process.
Transportation
A man uses a bicycle to cargo goods in Ouagadougou, Burkina Faso (2007)
Human powered-vehicles include the bicycle (and the bamboo bicycle), which provides general-purpose transportation at lower costs compared to motorized vehicles, and many advantages over walking, and the whirlwind wheelchair, which provides mobility for disabled people who cannot afford the expensive wheelchairs used in developed countries. Animal powered vehicles/transport may also be another appropriate technology. Certain zero-emissions vehicles may be considered appropriate transportation technology, including light rail, compressed air cars, liquid nitrogen and hydrogen-powered vehicles. Also, vehicles with internal combustion engines may be converted to hydrogen or oxyhydrogen combustion.
Bicycles can also be applied to commercial transport of goods to and from remote areas. An example of this is Karaba, a free-trade coffee co-op in Rwanda, which uses 400 modified bicycles to carry hundreds of pounds of coffee beans for processing.[22] Other projects for developing countries include the redesign of cycle rickshaws to convert them to electric power.[23][24] However recent reports suggest that these rickshaws are not plying on the roads.[25]
Health care
According to the Global Health Council, rather than the use of professionally schooled doctors, the training of villagers to remedy most maladies in towns in the developing world is most appropriate.[26] Trained villagers are able to eliminate 80% of the health problems. Small (low-cost) hospitals– based on the model of the Jamkhed hospital– can remedy another 15%, while only 5% will need to go to a larger (more expensive) hospital.
Before being able to determine the cause of the disease or malady, accurate diagnosis is required. This may be done manually (through observation, inquiries) and by specialized tools.
A phase-change incubator, developed in the late 1990s, is a low-cost way for health workers to incubate microbial samples.
Birth control is also seen as an appropriate technology, especially now, because of increasing population numbers (overpopulating certain areas), increasing food prices and poverty. It has been proposed to a certain degree by PATH (program for appropriate technology in health).[27][28]
Jaipur foot was developed by Dr. P. K. Sethi and Masterji Ram Chander in 1968 as an inexpensive prosthetic leg for victims of landmine explosions.
Natural cleaning products can be used for personal hygiene and cleaning of clothing and eating utensils; in order to decrease illnesses/maladies (as they eliminate a great amount of pathogens).
Note that many Appropriate Technologies benefit public health, in particular by providing sanitation and safe drinking water. Refrigeration may also provide a health benefit. (These are discussed in the following paragraphs.) This was too found at the Comprehensive Rural Health Project[30] and the Women Health Volunteers projects in countries as Iran, Iraq and Nepal.[31]
Crop production tools are best kept simple (reduces operating difficulty, cost, replacement difficulties and pollution, when compared to motorized equipment). Tools can include scythes,[33] animal-pulled plows[34] (although no-till farming should be preferred),[35]dibbers, wheeled augers[36][37] (for planting large trees), kirpis, hoes, etc.
Greenhouses are also sometimes included (see Earthship Biotincture).[citation needed] Sometimes they are also fitted with irrigation systems, and/or heat sink-systems which can respectively irrigate the plants or help to store energy from the sun and redistribute it at night (when the greenhouse starts to cool down).
According to proponents, Appropriate Technologies can greatly reduce the labor required to prepare food, compared to traditional methods, while being much simpler and cheaper than the processing used in Western countries. This reflects E.F. Schumacher's concept of "intermediate technology," i.e., technology which is significantly more effective and expensive than traditional methods, but still an order of magnitude (10 times) cheaper than developed world technology. Key examples are:
all other types of electrical or hand-operated kitchen equipment (grinders, cutters, etc.) Special multifunctional kitchen robots that are able to perform several functions (e.g., grinding, cutting, and even vacuum cleaning and polishing) are able to reduce costs even more. An example of these devices was the (now discontinued) Piccolo household appliance from Hammelmann Werke (previously based in Bad Kissingen). It was equipped with a flexible axis, allowing a variety of aids to be screwed on.[38][39]
In Ghana, Zouzugu villagers use solar cookers for preparing their meals
Solar cookers are appropriate to some settings, depending on climate and cooking style. They are emission-less and very low-cost. Hybrid variants also exist that incorporate a second heating source such as electrical heating or wood-based.
Hot plates are 100% electrical, fairly low cost (around €20) and are mobile. They do however require an electrical system to be present in the area of operation.
Rocket stoves and certain other woodstoves (e.g., Philips Woodstove[40]) improve fuel efficiency, and reduce harmful indoor air pollution. The stoves however still make use of wood. However, briquette makers can now turn organic waste into fuel, saving money and/or collection time, and preserving forests.
Solar, special Einstein refrigerators and thermal mass refrigerators reduce the amount of electricity required. Also, solar and special Einstein refrigerators do not use haloalkanes (which play a key role in ozone depletion), but use heat pumps or mirrors instead. Solar refrigerators have been built for developing nations by Sopology.[41][42]
The pot-in-pot refrigerator is an African invention which keeps things cool without electricity. It provides a way to keep food and produce fresh for much longer than would otherwise be possible. This can be a great benefit to the families who use the device. For example, it is claimed that girls who had to regularly sell fresh produce in the market can now go to school instead, as there is less urgency to sell the produce before it loses freshness.[43]
Information and communication technologies
Netbooks such as the Asus Eee PC accommodate low-cost information sharing and communication
The OLPC XO, Simputer, Asus Eee PC, and other low-cost computers are computers aimed at developing countries. Besides the low price, other characteristics include resistance to dust, reliability and use of the target language.
Eldis OnDisc and The Appropriate Technology Library are projects that use CDs and DVDs to give access to development information in areas without reliable and affordable internet access.
The wind-up radio and the computer and communication system planned by the Jhai Foundation are independent from power supply.
There is also GrameenPhone, which fused mobile telephony with Grameen Bank's microfinance program to give Bangladeshi villagers access to communication.
Mobile telephony is appropriate technology for many developing countries, as it greatly reduces the infrastructure required to achieve widespread coverage. However, mobile phone network may not always be available (it depends on the location) and may not always provide both voice and data services.
Loband, a website developed by Aptivate, strips all the photographic and other bandwidth-intensive content from webpages and renders them as simple text, while otherwise allowing one to browse them normally. The site greatly increases the speed of browsing, and is appropriate for use on low bandwidth connections as generally available in much of the developing world.
An increasing number of activists provide free or very inexpensive web and email services using cooperative computer networks that run wireless ad hoc networks. Network service is provided by a cooperative of neighbors, each operating a router as a household appliance. These minimize wired infrastructure, and its costs and vulnerabilities. Private IP networks set up in this way can operate without the use of a commercial provider.
Rural electrical grids can be wired with "optical phase cable", in which one or more of the steelarmor wires are replaced with steel tubes containing fiber optics.[44]
Satellite Internet access can provide high speed connectivity to remote locations, however these are significantly more expensive than wire-based or terrestrial wireless systems. Wimax and forms of packet radio can also be used. Depending on the speed and latency of these networks they may be capable of relaying VoIP traffic, negating the need for separate telephony services. Finally, the Internet Radio Linking Project provides potential for blending older (cheap) local radio broadcasting with the increased range of the internet.
Satellite-based telephone systems can also be used, as either fixed installations or portable handsets and can be integrated into a PABX or local IP-based network.
Finance
Through financial systems envisioned especially for the very poor/developed world, many companies have been able to get started with only limited capital. Often banks lend the money to people wishing to start a business (such as with microfinance). In other systems, people for a Rotating Savings and Credit Association or ROSCA to purchase costly material together (such as Tontines and Susu accounts). Organisations, communities, cities or individuals can provide loans to other communities/cities (such as with the approach followed by Kiva, World Vision Microloans, MicroPlace and LETS). Finally, in certain communities (usually isolated communities such as small islands or oases) everything of value is shared. This is called gift economy.
The adopters and implementers of a technology often have less bargaining and social power than those who design and provide the technology. In stakeholder negotiations and relationships, the uneven distribution of power often stems from the lack of access to capital. In the case of small-holder farming communities, for example, farmers struggle to access initial capital, and so outside investors have significantly more bargaining power.[45] This dynamic gives power to outside investors over farmers, technology adopters, and local community members. A local community's best interest might not always be considered by outside investing forces.
Related Research Articles
Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in multiple forms including radiation, chemical, gravitational potential, electrical potential, electricity, elevated temperature, latent heat and kinetic. Energy storage involves converting energy from forms that are difficult to store to more conveniently or economically storable forms.
Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy, and solar architecture. It is an essential source of renewable energy, and its technologies are broadly characterized as either passive solar or active solar depending on how they capture and distribute solar energy or convert it into solar power. Active solar techniques include the use of photovoltaic systems, concentrated solar power, and solar water heating to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light-dispersing properties, and designing spaces that naturally circulate air.
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower. Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. However, when constructed in lowland rainforest areas, where part of the forest is inundated, substantial amounts of greenhouse gases may be emitted.
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar energy to generate thermal energy for use in industry, and in the residential and commercial sectors.
Solar water heating (SWH) is heating water by sunlight, using a solar thermal collector. A variety of configurations are available at varying cost to provide solutions in different climates and latitudes. SWHs are widely used for residential and some industrial applications.
Energy development is the field of activities focused on obtaining sources of energy from natural resources. These activities include production of renewable, nuclear, and fossil fuel derived sources of energy, and for the recovery and reuse of energy that would otherwise be wasted. Energy conservation and efficiency measures reduce the demand for energy development, and can have benefits to society with improvements to environmental issues.
Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source.
Grid energy storage is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inexpensive or when demand is low, and later returned to the grid when demand is high, and electricity prices tend to be higher.
Rural electrification is the process of bringing electrical power to rural and remote areas. Rural communities are suffering from colossal market failures as the national grids fall short of their demand for electricity. As of 2019, 770 million people live without access to electricity – 10.2% of the global population. Electrification typically begins in cities and towns and gradually extends to rural areas, however, this process often runs into obstacles in developing nations. Expanding the national grid is expensive and countries consistently lack the capital to grow their current infrastructure. Additionally, amortizing capital costs to reduce the unit cost of each hook-up is harder to do in lightly populated areas. If countries are able to overcome these obstacles and reach nationwide electrification, rural communities will be able to reap considerable amounts of economic and social development.
Off-the-grid or off-grid is a characteristic of buildings and a lifestyle designed in an independent manner without reliance on one or more public utilities. The term "off-the-grid" traditionally refers to not being connected to the electrical grid, but can also include other utilities like water, gas, and sewer systems, and can scale from residential homes to small communities. Off-the-grid living allows for buildings and people to be self-sufficient, which is advantageous in isolated locations where normal utilities cannot reach and is attractive to those who want to reduce environmental impact and cost of living. Generally, an off-grid building must be able to supply energy and potable water for itself, as well as manage food, waste and wastewater.
Microgeneration is the small-scale production of heat or electric power from a "low carbon source," as an alternative or supplement to traditional centralized grid-connected power.
Solar-powered pumps run on electricity generated by photovoltaic (PV) panels or the radiated thermal energy available from collected sunlight as opposed to grid electricity- or diesel-run water pumps. Generally, solar-powered pumps consist of a solar panel array, solar charge controller, DC water pump, fuse box/breakers, electrical wiring, and a water storage tank. The operation of solar-powered pumps is more economical mainly due to the lower operation and maintenance costs and has less environmental impact than pumps powered by an internal combustion engine. Solar pumps are useful where grid electricity is unavailable or impractical, and alternative sources do not provide sufficient energy.
Solar air conditioning, or "solar-powered air conditioning", refers to any air conditioning (cooling) system that uses solar power.
For solar power, South Asia has the ideal combination of both high solar insolation and a high density of potential customers.
The developing nations of Africa are popular locations for the application of renewable energy technology. Currently, many nations already have small-scale solar, wind, and geothermal devices in operation providing energy to urban and rural populations. These types of energy production are especially useful in remote locations because of the excessive cost of transporting electricity from large-scale power plants. The applications of renewable energy technology has the potential to alleviate many of the problems that face Africans every day, especially if done in a sustainable manner that prioritizes human rights.
Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Photovoltaic cells convert light into an electric current using the photovoltaic effect. Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus a large area of sunlight to a hot spot, often to drive a steam turbine.
Renewable energy in developing countries is an increasingly used alternative to fossil fuel energy, as these countries scale up their energy supplies and address energy poverty. Renewable energy technology was once seen as unaffordable for developing countries. However, since 2015, investment in non-hydro renewable energy has been higher in developing countries than in developed countries, and comprised 54% of global renewable energy investment in 2019. The International Energy Agency forecasts that renewable energy will provide the majority of energy supply growth through 2030 in Africa and Central and South America, and 42% of supply growth in China.
Reverse osmosis (RO) is a water purification process that uses a partially permeable membrane to separate ions, unwanted molecules and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property that is driven by chemical potential differences of the solvent, a thermodynamic parameter. Reverse osmosis can remove many types of dissolved and suspended chemical species as well as biological ones (principally bacteria) from water, and is used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be "selective", this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as solvent molecules, e.g., water, H2O) to pass freely.
The Appropriate Technology Collaborative is a U.S. Non-profit dedicated to designing everyday technologies for the global poor.
There are many practical applications for solar panels or photovoltaics. From the fields of the agricultural industry as a power source for irrigation to its usage in remote health care facilities to refrigerate medical supplies. Other applications include power generation at various scales and attempts to integrate them into homes and public infrastructure. PV modules are used in photovoltaic systems and include a large variety of electrical devices.
References
1 2 3 4 5 Panneerselvam, P.; Halberg, Niels; Lockie, Stewart (2012). "Consequences of organic agriculture for smallholder farmers' livelihood and food security". In Halberg, Niels; Muller, Adrian (eds.). Organic Agriculture for Sustainable Livelihoods. pp.37–60. doi:10.4324/9780203128480-9. ISBN978-0-203-12848-0.
↑ Murphy, Heather M.; McBean, Edward A.; Farahbakhsh, Khosrow (May 2009). "Appropriate technology – A comprehensive approach for water and sanitation in the developing world". Technology in Society. 31 (2): 158–167. doi:10.1016/j.techsoc.2009.03.010.
↑ Northern Economics Inc. and Electric Power Systems Inc. April 2001. "Screening Report for Alaska Rural Energy Plan."Archived February 16, 2008, at the Wayback Machine (Report published on government website). Alaska Department of Commerce, Community, and Economic Development, via dced.state.ak.us. Retrieved on 16 September 2007.
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