84-401: SpaceCub was a design project for a homebuilt rocket. Between 1993 and 1994, Geoffrey A. Landis proposed that a vehicle designed to launch to the edge of space might be a feasible project for a "personal" spaceship, the equivalent of a Piper Cub for space. The insight was that a flight to "only" 100 km would reach the officially defined edge of space, and even though this is much easier
168-925: A 1,300 m (14,000 sq ft) collector in Coimbatore , India, used for drying marigolds. Solar distillation can be used to make saline or brackish water potable. The first recorded instance of this was by 16th-century Arab alchemists. A large-scale solar distillation project was first constructed in 1872 in the Chilean mining town of Las Salinas. The plant, which had solar collection area of 4,700 m (51,000 sq ft), could produce up to 22,700 L (5,000 imp gal; 6,000 US gal) per day and operate for 40 years. Individual still designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect. These stills can operate in passive, active, or hybrid modes. Double-slope stills are
252-477: A 1993 paper, he suggested the use of a phased program of Mars exploration, with a series of incremental achievements leading up to human landings on Mars. Landis was a fellow of the NASA Institute for Advanced Concepts ("NIAC"), where he worked on a project investigating the use of laser- and particle-beam pushed sails for propulsion for interstellar flight . In 2002 Landis addressed the annual convention of
336-601: A building for better daylighting , selecting materials with favorable thermal mass or light-dispersing properties, and organize spaces that naturally circulate air . In 2011, the International Energy Agency said that "the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries' energy security through reliance on an indigenous, inexhaustible, and mostly import-independent resource, enhance sustainability , reduce pollution , lower
420-411: A challenge than an orbital flight , such a suborbital flight would be of excitement to the public, and the pilot would be officially qualified as an astronaut . A small group of rocket enthusiasts, computer hobbyists, and science-fiction writers gathered together to do a preliminary design, with the ultimate goal of moving on to building a prototype, with (then) physics student David Burkhead leading
504-531: A conventional steam-generator to produce superheated steam for a turbine/generator as used in any conventional coal, oil, or nuclear power plant. A 100-megawatt turbine would need a tank about 9.1 metres (30 ft) tall and 24 metres (79 ft) in diameter to drive it for four hours by this design. Several parabolic trough power plants in Spain and solar power tower developer SolarReserve use this thermal energy storage concept. The Solana Generating Station in
588-614: A cooking container. These cookers reach temperatures of 315 °C (599 °F) and above but require direct light to function properly and must be repositioned to track the Sun. Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. The first commercial system was the Solar Total Energy Project (STEP) in Shenandoah, Georgia, US where
672-494: A field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory. This grid-connected cogeneration system provided 400 kW of electricity plus thermal energy in the form of 401 kW steam and 468 kW chilled water and had a one-hour peak load thermal storage. Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation . The use of evaporation ponds to obtain salt from seawater
756-453: A full-scale prototype of the SpaceCub was never built, the design (and the publicity surrounding the project) brought public attention to the concept that a small vehicle to fly a private pilot into space might be possible, and in that way served to stimulate the X Prize , which adopted the SpaceCub's goal of a 100-km flight altitude as a target for a competition. In its way, the SpaceCub vehicle
840-471: A full-scale steam engine powered by low-pressure water, enabling him to patent the entire solar engine system by 1912. Shuman built the world's first solar thermal power station in Maadi , Egypt , between 1912 and 1913. His plant used parabolic troughs to power a 45–52 kilowatts (60–70 hp ) engine that pumped more than 22,000 litres (4,800 imp gal; 5,800 US gal) of water per minute from
924-560: A high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle . The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as wind, cyclones and anticyclones . Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C. By photosynthesis , green plants convert solar energy into chemically stored energy, which produces food, wood and
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#17328632044821008-572: A large area of sunlight to a hot spot, often to drive a steam turbine . Photovoltaics (PV) were initially solely used as a source of electricity for small and medium-sized applications, from the calculator powered by a single solar cell to remote homes powered by an off-grid rooftop PV system. Commercial concentrated solar power plants were first developed in the 1980s. Since then, as the cost of solar panels has fallen, grid-connected solar PV systems ' capacity and production has doubled about every three years . Three-quarters of new generation capacity
1092-642: A nomination for the John W. Campbell Award for Best New Writer . In the field of science fiction, Landis has published over 70 works of short fiction, and two books. He won the 1989 Nebula Award for best short story for " Ripples in the Dirac Sea " ( Asimov's Science Fiction , October 1988), the 1992 Hugo Award for " A Walk in the Sun " ( Asimov's Science Fiction , October 1991), and the 2003 Hugo for his short story " Falling onto Mars " ( Analog Science Fiction and Fact , July/Aug 2002). His first novel, Mars Crossing ,
1176-538: A portion of this energy. Use of solar for heating can roughly be divided into passive solar concepts and active solar concepts, depending on whether active elements such as sun tracking and solar concentrator optics are used. Thermal mass is any material that can be used to store heat—heat from the Sun in the case of solar energy. Common thermal mass materials include stone, cement, and water. Historically they have been used in arid climates or warm temperate regions to keep buildings cool by absorbing solar energy during
1260-512: A reference to the energy retained by storing heat before turning it into electricity, versus converting heat directly into electricity. The molten salt mixtures vary. The most extended mixture contains sodium nitrate , potassium nitrate and calcium nitrate . It is non-flammable and non-toxic, and has already been used in the chemical and metals industries as a heat-transport fluid. Hence, experience with such systems exists in non-solar applications. The salt melts at 131 °C (268 °F). It
1344-412: A small part in the near-ultraviolet . Most of the world's population live in areas with insolation levels of 150–300 watts/m , or 3.5–7.0 kWh /m per day. Solar radiation is absorbed by the Earth's land surface, oceans – which cover about 71% of the globe – and atmosphere. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or convection . When the air reaches
1428-454: A star ship with a diamond sail, a few nanometres thick, powered by solar energy, which could achieve "10 per cent of the speed of light". He was selected again as a NASA Innovative Advanced Concepts fellow in 2012, with feasibility concept of a landsailing rover for Venus exploration, called Venus Landsailing Rover , and in 2015 was the science lead on a NIAC study to design a mission to Neptune 's moon Triton . In 2017, Landis's work
1512-480: A steam engine. In 1908 Shuman formed the Sun Power Company with the intent of building larger solar power plants. He, along with his technical advisor A.S.E. Ackermann and British physicist Sir Charles Vernon Boys , developed an improved system using mirrors to reflect solar energy upon collector boxes, increasing heating capacity to the extent that water could now be used instead of ether. Shuman then constructed
1596-442: A tenth of their electricity from solar, with China making up more than half of solar growth. Almost half the solar power installed in 2022 was mounted on rooftops . Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated heat is then used as a heat source for a conventional power plant. A wide range of concentrating technologies exists;
1680-422: Is a biannual solar-powered car race, where teams from universities and enterprises compete over 3,021 kilometres (1,877 mi) across central Australia from Darwin to Adelaide . In 1987, when it was founded, the winner's average speed was 67 kilometres per hour (42 mph) and by 2007 the winner's average speed had improved to 90.87 kilometres per hour (56.46 mph). The North American Solar Challenge and
1764-439: Is a classic example of passive solar design. The most recent approaches to solar design use computer modeling tying together solar lighting , heating and ventilation systems in an integrated solar design package. Active solar equipment such as pumps, fans, and switchable windows can complement passive design and improve system performance. Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of
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#17328632044821848-450: Is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building. As the chimney warms, the air inside is heated, causing an updraft that pulls air through the building. Performance can be improved by using glazing and thermal mass materials in a way that mimics greenhouses. Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on
1932-481: Is a predecessor to many of today's concepts for space tourism . Geoffrey A. Landis Geoffrey Alan Landis ( / ˈ l æ n d ɪ s / ; born May 28, 1955) is an American aerospace engineer and author , working for the National Aeronautics and Space Administration (NASA) on planetary exploration , interstellar propulsion , solar power and photovoltaics . He holds nine patents, primarily in
2016-409: 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 designing
2100-441: Is challenging; a feasible alternative is hydrogen production from protons, though use of water as the source of electrons (as plants do) requires mastering the multielectron oxidation of two water molecules to molecular oxygen. Some have envisaged working solar fuel plants in coastal metropolitan areas by 2050 – the splitting of seawater providing hydrogen to be run through adjacent fuel-cell electric power plants and
2184-763: Is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high. The Squad Solar is a Neighborhood Electric Vehicle that has a solar roof and can be plugged into a normal 120 volt outlet to be charged. Solar chemical processes use solar energy to drive chemical reactions. These processes offset energy that would otherwise come from a fossil fuel source and can also convert solar energy into storable and transportable fuels. Solar induced chemical reactions can be divided into thermochemical or photochemical . A variety of fuels can be produced by artificial photosynthesis . The multielectron catalytic chemistry involved in making carbon-based fuels (such as methanol ) from reduction of carbon dioxide
2268-399: Is kept liquid at 288 °C (550 °F) in an insulated "cold" storage tank. The liquid salt is pumped through panels in a solar collector where the focused irradiance heats it to 566 °C (1,051 °F). It is then sent to a hot storage tank. This is so well insulated that the thermal energy can be usefully stored for up to a week. When electricity is needed, the hot salt is pumped to
2352-788: Is married to science fiction writer Mary A. Turzillo and lives in Berea, Ohio . After receiving his doctorate at Brown University, Landis worked at the NASA Lewis Research Center (now NASA Glenn) and the Ohio Aerospace Institute before accepting a permanent position at the NASA John Glenn Research Center , where he does research on Mars missions, solar energy , and technology development for future space missions. He holds nine patents, and has authored or co-authored more than 300 published scientific papers in
2436-581: Is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams. Clothes lines , clotheshorses , and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. In some states of the United States legislation protects the "right to dry" clothes. Unglazed transpired collectors (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise
2520-565: Is recommended by the World Health Organization as a viable method for household water treatment and safe storage. Over two million people in developing countries use this method for their daily drinking water. Solar energy may be used in a water stabilization pond to treat waste water without chemicals or electricity. A further environmental advantage is that algae grow in such ponds and consume carbon dioxide in photosynthesis, although algae may produce toxic chemicals that make
2604-489: Is solar, with both millions of rooftop installations and gigawatt-scale photovoltaic power stations continuing to be built. In 2023, solar power generated 5.5% (1,631 TWh) of global electricity and over 1% of primary energy , adding twice as much new electricity as coal. Along with onshore wind power , utility-scale solar is the source with the cheapest levelised cost of electricity for new installations in most countries. As of 2023, 33 countries generated more than
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2688-513: Is the box cooker first built by Horace de Saussure in 1767. A basic box cooker consists of an insulated container with a transparent lid. It can be used effectively with partially overcast skies and will typically reach temperatures of 90–150 °C (194–302 °F). Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers. Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on
2772-420: Is the dominant application of solar hot water with an installed capacity of 18 GW th as of 2005. In the United States, heating, ventilation and air conditioning (HVAC) systems account for 30% (4.65 EJ/yr) of the energy used in commercial buildings and nearly 50% (10.1 EJ/yr) of the energy used in residential buildings. Solar heating, cooling and ventilation technologies can be used to offset
2856-693: The Gossamer Penguin made the first piloted flights powered solely by photovoltaics. This was quickly followed by the Solar Challenger which crossed the English Channel in July 1981. In 1990 Eric Scott Raymond in 21 hops flew from California to North Carolina using solar power. Developments then turned back to unmanned aerial vehicles (UAV) with the Pathfinder (1997) and subsequent designs, culminating in
2940-456: The Helios which set the altitude record for a non-rocket-propelled aircraft at 29,524 metres (96,864 ft) in 2001. The Zephyr , developed by BAE Systems , is the latest in a line of record-breaking solar aircraft, making a 54-hour flight in 2007, and month-long flights were envisioned by 2010. From March 2015 to July 2016, Solar Impulse , an electric aircraft , successfully circumnavigated
3024-552: The American Association for the Advancement of Science on the possibilities and challenges of interstellar travel in what was described as the "first serious discussion of how mankind will one day set sail to the nearest star". Dr. Landis said, "This is the first meeting to really consider interstellar travel by humans. It is historic. We're going to the stars. There really isn't a choice in the long term." He went on to describe
3108-565: The Hessler Street Fair poetry contest for his poem "Five Pounds of Sunlight", and first place in 2010 for "Human Potential". His poetry collection Iron Angels was published in 2009. Landis has also written non-fiction and popular science articles, encyclopedia articles and columns for a large range of publications, including Analog Science Fiction and Fact , Space Sciences , Asimov's Science Fiction , Spaceflight , and Science Fiction Age . His article "The Demon Under Hawaii" won
3192-524: The Mars Geyser Hopper spacecraft, a Discovery-class mission concept that would investigate the springtime carbon dioxide Martian geysers found in regions around the south pole of Mars , the Human Exploration using Real-time Robotic Operations ("HERRO") concept for telerobotic Mars exploration, and concepts for use of In-situ resource utilization for a Mars sample-return mission . In
3276-482: The Nile River to adjacent cotton fields. Although the outbreak of World War I and the discovery of cheap oil in the 1930s discouraged the advancement of solar energy, Shuman's vision, and basic design were resurrected in the 1970s with a new wave of interest in solar thermal energy. In 1916 Shuman was quoted in the media advocating solar energy's utilization, saying: We have proved the commercial profit of sun power in
3360-564: The Rhysling Award twice, for his poems "Christmas, after we all get time machines" in 2000 (which also won the 2000 Asimov's Reader's Award for best poem ), and for "Search" in 2009, and the Dwarf Stars Award in 2010, for the poem "Fireflies". He has won the Asimov's Reader's award for best poem three times, most recently in 2014, for his poem "Rivers". In 2009, he won second place in
3444-601: The Theodore Sturgeon Award for best short science fiction story, and was nominated for both the Nebula and Hugo awards. He attended the Clarion Workshop in 1985, with other emerging SF writers such as Kristine Kathryn Rusch , Martha Soukup , William Shunn , Resa Nelson, Mary Turzillo and Robert J. Howe. Landis has also published a number of poems, much of it involving science fiction or science themes. He won
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3528-462: The biomass from which fossil fuels are derived. The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 122 PW·year = 3,850,000 exajoules (EJ) per year. In 2002 (2019), this was more energy in one hour (one hour and 25 minutes) than the world used in one year. Photosynthesis captures approximately 3,000 EJ per year in biomass. The potential solar energy that could be used by humans differs from
3612-670: The 2015 Space Studies Program in Athens, Ohio . As a writer, he was an instructor at the Clarion Writers Workshop at Michigan State University in 2001. He was a guest instructor at the Launch Pad workshop for 2012. Landis' first science fiction story, " Elemental ", appeared in Analog in December 1984, and was nominated for the 1985 Hugo Award for Best Novella . as well as earning him
3696-638: The Analog Analytical Laboratory Award for best science article in 1993. Writing influences include Arthur C. Clarke , Isaac Asimov , Robert A. Heinlein , Ursula K. Le Guin , Kurt Vonnegut , Larry Niven , and John Varley . ——————— Solar energy Solar energy is the radiant energy from the Sun 's light and heat , which can be harnessed using a range of technologies such as solar electricity , solar thermal energy (including solar water heating ) and solar architecture . It
3780-541: The Cerro Dominador plant is capable of generating around 110 MW of power. The plant has an advanced storage system enabling it to generate electricity for up to 17.5 hours without direct solar radiation, which allows it to provide a stable electricity supply without interruptions if required. The Project secured up to 950 GW·h per year sale. Another project is the María Elena plant is a 400 MW thermo-solar complex in
3864-497: The Equator-facing side of a building because they will interfere with winter solar availability. They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting winter solar gain . Solar cookers use sunlight for cooking, drying, and pasteurization . They can be grouped into three broad categories: box cookers, panel cookers, and reflector cookers. The simplest solar cooker
3948-721: The Martian surface, including studies of the performance of photovoltaic cells in the Mars environment, the effect of Martian dust on performance, and technologies for dust removal from the arrays. He was a member of the Rover team on the Mars Pathfinder mission, and named the Mars rock, " Yogi ". He is a member of the science team on the 2003 Mars Exploration Rovers mission, where his work includes observations of Martian dust devils, atmospheric science measurements, and observation of frost on
4032-540: The NASA Space Flight Awareness award and the Rotary National Award for Space Achievement Stellar Award in 2016. Much of Landis' technical work has been in the field of developing solar cells and arrays , both for terrestrial use and for spacecraft. Landis has worked on a number of projects related to developing technology of human and robotic exploration of Mars and scientific analysis of
4116-532: The Roman emperor Tiberius . The first modern greenhouses were built in Europe in the 16th century to keep exotic plants brought back from explorations abroad. Greenhouses remain an important part of horticulture today. Plastic transparent materials have also been used to similar effect in polytunnels and row covers . Development of a solar-powered car has been an engineering goal since the 1980s. The World Solar Challenge
4200-499: The Sun. Active solar techniques use photovoltaics, concentrated solar power , solar thermal collectors , pumps, and fans to convert sunlight into useful output. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun. Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce
4284-457: The U.S. has six hours of storage by molten salt. In Chile, The Cerro Dominador power plant has a 110 MW solar-thermal tower, the heat is transferred to molten salts . The molten salts then transfer their heat in a heat exchanger to water, generating superheated steam, which feeds a turbine that transforms the kinetic energy of the steam into electric energy using the Rankine cycle . In this way,
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#17328632044824368-639: The Universal Exposition in Paris, Augustin Mouchot successfully demonstrated a solar steam engine but could not continue development because of cheap coal and other factors. In 1897, Frank Shuman , a US inventor, engineer and solar energy pioneer built a small demonstration solar engine that worked by reflecting solar energy onto square boxes filled with ether, which has a lower boiling point than water and were fitted internally with black pipes which in turn powered
4452-420: The amount of solar energy present near the surface of the planet because factors such as geography, time variation, cloud cover, and the land available to humans limit the amount of solar energy that we can acquire. In 2021, Carbon Tracker Initiative estimated the land area needed to generate all our energy from solar alone was 450,000 km — or about the same as the area of Sweden , or the area of Morocco , or
4536-591: The area of California (0.3% of the Earth's total land area). Solar technologies are categorized as either passive or active depending on the way they capture, convert and distribute sunlight and enable solar energy to be harnessed at different levels around the world, mostly depending on the distance from the Equator. Although solar energy refers primarily to the use of solar radiation for practical ends, all types of renewable energy, other than geothermal power and tidal power , are derived either directly or indirectly from
4620-538: The capture of solar energy to optimize the productivity of plants. Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields. While sunlight is generally considered a plentiful resource, the exceptions highlight the importance of solar energy to agriculture. During the short growing seasons of the Little Ice Age , French and English farmers employed fruit walls to maximize
4704-551: The collection of solar energy. These walls acted as thermal masses and accelerated ripening by keeping plants warm. Early fruit walls were built perpendicular to the ground and facing south, but over time, sloping walls were developed to make better use of sunlight. In 1699, Nicolas Fatio de Duillier even suggested using a tracking mechanism which could pivot to follow the Sun. Applications of solar energy in agriculture aside from growing crops include pumping water, drying crops, brooding chicks and drying chicken manure. More recently
4788-434: The costs of mitigating global warming .... these advantages are global". The Earth receives 174 petawatts (PW) of incoming solar radiation ( insolation ) at the upper atmosphere . Approximately 30% is reflected back to space while the rest, 122 PW, is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with
4872-479: The day and radiating stored heat to the cooler atmosphere at night. However, they can be used in cold temperate areas to maintain warmth as well. The size and placement of thermal mass depend on several factors such as climate, daylighting, and shading conditions. When duly incorporated, thermal mass maintains space temperatures in a comfortable range and reduces the need for auxiliary heating and cooling equipment. A solar chimney (or thermal chimney, in this context)
4956-594: The equator of Mars. He was also a member of the Mars ISPP Propellant Precursor experiment team for the Mars Surveyor 2001 Lander mission, an experiment package to demonstrate manufacture of oxygen from the Martian atmosphere (which was cancelled after the failure of the Mars Polar Lander ). He has also done work on analyzing concepts for future robotic and human mission to Mars . These include
5040-564: The field of improvements to solar cells and photovoltaic devices and has given presentations and commentary on the possibilities for interstellar travel and construction of bases on the Moon , Mars , and Venus . Supported by his scientific background Landis also writes hard science fiction . For these writings he has won a Nebula Award , two Hugo Awards , and a Locus Award , as well as two Rhysling Awards for his poetry. He contributes science articles to various academic publications. Landis
5124-559: The fields of astronautics and photovoltaics. Landis has commented on the practicalities of generating oxygen and creating building materials for a future Moon base in New Scientist , and on the possibilities of using readily available metallic iron to manufacture steel on Mars. He is the recipient of numerous professional honors, including the American Institute of Aeronautics and Astronautics Aerospace Power Systems Award ,
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#17328632044825208-454: The fine glass surfaces of solar power plants. Metal grills would allow a high percentage of sunlight to enter the mirrors and solar panels while also preventing most damage. Sunlight has influenced building design since the beginning of architectural history. Advanced solar architecture and urban planning methods were first employed by the Greeks and Chinese , who oriented their buildings toward
5292-704: The first solar-powered crossing of the Pacific Ocean, and the Sun21 catamaran made the first solar-powered crossing of the Atlantic Ocean in the winter of 2006–2007. There were plans to circumnavigate the globe in 2010. In 1974, the unmanned AstroFlight Sunrise airplane made the first solar flight. On 29 April 1979, the Solar Riser made the first flight in a solar-powered, fully controlled, man-carrying flying machine, reaching an altitude of 40 ft (12 m). In 1980,
5376-476: The globe. It is a single-seat plane powered by solar cells and capable of taking off under its own power. The design allows the aircraft to remain airborne for several days. A solar balloon is a black balloon that is filled with ordinary air. As sunlight shines on the balloon, the air inside is heated and expands, causing an upward buoyancy force, much like an artificially heated hot air balloon . Some solar balloons are large enough for human flight, but usage
5460-575: The incoming air temperature up to 22 °C (40 °F) and deliver outlet temperatures of 45–60 °C (113–140 °F). The short payback period of transpired collectors (3 to 12 years) makes them a more cost-effective alternative than glazed collection systems. As of 2003, over 80 systems with a combined collector area of 35,000 square metres (380,000 sq ft) had been installed worldwide, including an 860 m (9,300 sq ft) collector in Costa Rica used for drying coffee beans and
5544-507: The most developed are the parabolic trough, the solar tower collectors, the concentrating linear Fresnel reflector, and the Stirling dish. Various techniques are used to track the Sun and focus light. In all of these systems, a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage. Designs need to account for the risk of a dust storm , hail , or another extreme weather event that can damage
5628-422: The most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications. Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours. Exposure times vary depending on weather and climate from a minimum of six hours to two days during fully overcast conditions. It
5712-494: The need for alternative resources and are generally considered demand-side technologies. In 2000, the United Nations Development Programme , UN Department of Economic and Social Affairs, and World Energy Council published an estimate of the potential solar energy that could be used by humans each year. This took into account factors such as insolation, cloud cover, and the land that is usable by humans. It
5796-471: The northern Chilean region of Antofagasta employing molten salt technology. Solar power , also known as solar electricity, is the conversion of energy from sunlight into electricity , either directly using photovoltaics (PV) or indirectly using concentrated solar power . Solar panels use the photovoltaic effect to convert light into an electric current . Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus
5880-566: The planned South African Solar Challenge are comparable competitions that reflect an international interest in the engineering and development of solar powered vehicles. Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption. In 1975, the first practical solar boat was constructed in England. By 1995, passenger boats incorporating PV panels began appearing and are now used extensively. In 1996, Kenichi Horie made
5964-561: The pure water by-product going directly into the municipal water system. In addition, chemical energy storage is another solution to solar energy storage. Hydrogen production technologies have been a significant area of solar chemical research since the 1970s. Aside from electrolysis driven by photovoltaic or photochemical cells, several thermochemical processes have also been explored. One such route uses concentrators to split water into oxygen and hydrogen at high temperatures (2,300–2,600 °C or 4,200–4,700 °F). Another approach uses
6048-414: The south to provide light and warmth. The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass . When these features are tailored to the local climate and environment, they can produce well-lit spaces that stay in a comfortable temperature range. Socrates ' Megaron House
6132-477: The southern side of a building in the northern hemisphere or the northern side in the southern hemisphere, their leaves provide shade during the summer, while the bare limbs allow light to pass during the winter. Since bare, leafless trees shade 1/3 to 1/2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of winter heating. In climates with significant heating loads, deciduous trees should not be planted on
6216-852: The surrounding environment. The higher temperatures result from increased absorption of solar energy by urban materials such as asphalt and concrete, which have lower albedos and higher heat capacities than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and to plant trees in the area. Using these methods, a hypothetical "cool communities" program in Los Angeles has projected that urban temperatures could be reduced by approximately 3 °C at an estimated cost of US$ 1 billion, giving estimated total annual benefits of US$ 530 million from reduced air-conditioning costs and healthcare savings. Agriculture and horticulture seek to optimize
6300-467: The technical effort. The vehicle design was discussed in many venues, and presentations on the design progress were given in several conferences, such as the 1995 NSS International Space Development Conference , where it attracted considerable popular attention. The design was featured in print in places including the December 1994 Popular Mechanics , and the Brazilian popular magazine Istoé . Although
6384-409: The technology has been embraced by vintners , who use the energy generated by solar panels to power grape presses. Greenhouses convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. Primitive greenhouses were first used during Roman times to produce cucumbers year-round for
6468-414: The total installed capacity of solar hot water systems was approximately 436 thermal gigawatt (GW th ), and China is the world leader in their deployment with 309 GW th installed, taken up 71% of the market. Israel and Cyprus are the per capita leaders in the use of solar hot water systems with over 90% of homes using them. In the United States, Canada, and Australia, heating swimming pools
6552-699: The tropics and have more particularly proved that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the Sun. Solar hot water systems use sunlight to heat water. In middle geographical latitudes (between 40 degrees north and 40 degrees south), 60 to 70% of the domestic hot water use, with water temperatures up to 60 °C (140 °F), can be provided by solar heating systems. The most common types of solar water heaters are evacuated tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot water; and unglazed plastic collectors (21%) used mainly to heat swimming pools. As of 2015,
6636-451: The water unusable. Molten salt can be employed as a thermal energy storage method to retain thermal energy collected by a solar tower or solar trough of a concentrated solar power plant so that it can be used to generate electricity in bad weather or at night. It was demonstrated in the Solar Two project from 1995 to 1999. The system is predicted to have an annual efficiency of 99%,
6720-611: Was born in Detroit, Michigan, and lived in Virginia , Maryland , Philadelphia , and Illinois during his childhood. His senior education was at New Trier High School , Winnetka, Illinois . He holds undergraduate degrees in physics and electrical engineering from the Massachusetts Institute of Technology (MIT). He also holds masters degrees in physics and engineering and a PhD in solid-state physics from Brown University . He
6804-793: Was on the faculty of the Department of Mining, Manufacturing, and Robotics in the Space Studies Program, and in 1999 he was on the faculty of the 12th Space Studies Program at the Suranaree University of Technology in Nakhon Ratchasima , Thailand . and co-chair of the student project "Out of the Cradle". He was also a guest lecturer at the ISU 13th Space Studies Program in Valparaíso , Chile , and
6888-585: Was published by Tor Books in 2000, winning a Locus Award . A short story collection, Impact Parameter (and Other Quantum Realities) , was published by Golden Gryphon Press in 2001 and named as noteworthy by trade magazine Publishers Weekly . He has also won the Analog Analytical Laboratory Award for the novelette The Man in the Mirror (2009). His 2010 novella The Sultan of the Clouds won
6972-461: Was stated that solar energy has a global potential of 1,600 to 49,800 exajoules (4.4 × 10 to 1.4 × 10 kWh) per year (see table below) . Quantitative relation of global solar potential vs. the world's primary energy consumption : Source: United Nations Development Programme – World Energy Assessment (2000) Solar thermal technologies can be used for water heating, space heating, space cooling and process heat generation. In 1878, at
7056-600: Was the subject of the book Land-Sailing Venus Rover With NASA Inventor Geoffrey Landis , published by World Book as part of their "Out of This World" book series for ages 10–14+. In 2005–2006, he was named the Ronald E. McNair Visiting Professor of Astronautics at MIT , and won the AIAA Abe M. Zarem Educator Award in 2007. Landis has also been a faculty member of the International Space University ; in 1998 he
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