Solar_energy

context: Solar energy is radiant light and heat from the Sun harnessed using a range of ever-evolving technologies such as solar heating, photovoltaics, solar thermal energy, solar architecture and artificial photosynthesis.
qas: answers: text: the Sun
question: Where does solar energy come from?

answers: text: Solar energy
question: What kind of energy consists of the light and heat provided by the Sun?

answers: text: solar heating, photovoltaics, solar thermal energy, solar architecture and artificial photosynthesis
question: What technologies are used to harness solar energy from the sun?

answers: text: radiant light and heat from the Sun
question: What is solar energy?

context: The Earth receives 174,000 terawatts (TW) of incoming solar radiation (insolation) at the upper atmosphere. Approximately 30% is reflected back to space while the rest 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 a small part in the near-ultraviolet. Most people around the world live in areas with insolation levels of 150 to 300 watts per square meter or 3.5 to 7.0 kWh/m2 per day.
qas: answers: text: 174,000
question: How many terawatts of solar radiation does the Earth receive?

answers: text: 30%
question: What percentage of solar radiation is reflected back by the atmosphere?

answers: text: 3.5 to 7.0
question: The areas that people live in typically receive what range of kWh/m2 per day?

answers: text: 174,000
question: How many terrawatts of radiation does the earth receive?

answers: text: Approximately 30%
question: How much of the solar radiation is reflected back into space?

answers: text: 150 to 300 watts per square meter or 3.5 to 7.0 kWh/m2 per day
question: What are the insolation levels of most populated areas?

answers: text: clouds, oceans and land masses
question: Where is the solar radiation not reflected back to space absorbed?

context: 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 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 anti-cyclones. 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 the biomass from which fossil fuels are derived.
qas: answers: text: 71
question: The Earth's oceans cover what percentage of the globe?

answers: text: 14
question: What is the average temperature of the Earth's surface in Celsius?

answers: text: photosynthesis
question: What is the process by which green plants convert solar energy to stored energy?

answers: text: about 71%
question: How much of the earth is covered by oceans?

answers: text: Warm air containing evaporated water from the oceans rises
question: What is the cause of atmospheric circulation?

answers: text: When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds
question: How does the water vapor that rises in warm air turn into clouds?

answers: text: The latent heat of water condensation amplifies convection
question: What creates wind, cyclones and anti-cyclones?

answers: text: photosynthesis
question: What is the process in which plants convert solar energy into stored energy called?

context: The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. In 2002, this was more energy in one hour than the world used in one year. Photosynthesis captures approximately 3,000 EJ per year in biomass. The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined,
qas: answers: text: 3,850,000
question: Each year the Earth absorbs how much solar energy in exajoules?

answers: text: one year
question: In 2002, the Sun provided more energy in one hour than humans used in what span of time?

answers: text: 3,000
question: How much energy in exajoules does photosynthesis capture each year?

answers: text: one year
question: Twice the amount of energy obtainable by all the non-renewable sources  on Earth can be provided by the Sun in what span of time?

answers: text: approximately 3,850,000 exajoules (EJ) per year
question: What is the amount of solar energy absorbed by the earth?

answers: text: approximately 3,000 EJ per year
question: How much solar energy is captured by photosynthesis?

answers: text: coal, oil, natural gas, and mined uranium combined
question: The amount of solar energy per year is twice as much as the energy that will ever be produced from what resources?

context: Solar technologies are broadly characterized 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 distance from the equator. Although solar energy refers primarily to the use of solar radiation for practical ends, all renewable energies, other than geothermal and tidal, derive their energy from the Sun in a direct or indirect way.
qas: answers: text: the Sun
question: Where do the majority of renewable energies derive their energy from?

answers: text: passive or active
question: How are solar technologies defined?

answers: text: depending on the way they capture, convert and distribute sunlight
question: What is one way that characterizes solar technologies as passive or active?

answers: text: geothermal and tidal
question: Which renewable energies do not acquire their energy from the sun?

answers: text: direct or indirect
question: How do renewable energies acquire energy from the sun?

context: Active solar techniques use photovoltaics, concentrated solar power, solar thermal collectors, pumps, and fans to convert sunlight into useful outputs. 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 the need for alternate resources and are generally considered demand side technologies.
qas: answers: text: Active
question: Are supply side solar technologies generally active or passive?

answers: text: Passive
question: Are demand side solar technologies generally active or passive?

answers: text: solar thermal collectors
question: What is an active solar technique used to generate energy?

answers: text: designing spaces that naturally circulate air
question: What is an active solar technique used to generate energy?

answers: text: increase the supply of energy
question: What does an active solar technique do?

answers: text: reduce the need for alternate resources
question: What does a passive solar technique do?

context: In 1897, Frank Shuman, a U.S. 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 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 a full-scale steam engine powered by low-pressure water, enabling him to patent the entire solar engine system by 1912.
qas: answers: text: Frank Shuman
question: What was the name of the inventor who built a solar engine in 1897?

answers: text: 1908
question: In what year was the Sun Power Company formed?

answers: text: 1912
question: Shuman patented his solar engine system in what year?

answers: text: a U.S. inventor, engineer and solar energy pioneer
question: Who is Frank Shuman?

answers: text: 1897
question: In what year did solar engine build his solar engine?

answers: text: steam engine
question: What was the solar engine used to power?

answers: text: 1908
question: In what year was the Sun Power Company established?

answers: text: 1912
question: In what year did Frank Shuman patent his solar engine?

context: Shuman built the world’s first solar thermal power station in Maadi, Egypt, between 1912 and 1913. Shuman’s 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 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:
qas: answers: text: Maadi, Egypt
question: Where did Shuman build the world's first solar thermal power station?

answers: text: 22,000
question: How many liters of water per minute did Shuman's engine pump in litres?

answers: text: the 1970s
question: In what decade were Shuman's ideas about solar energy revived?

answers: text: Maadi, Egypt
question: Where was the first solar thermal power plant built?

answers: text: parabolic troughs
question: What was used to power the plants engine?

answers: text: Nile River
question: From what river did the engine pump water?

answers: text: the outbreak of World War I and the discovery of cheap oil
question: What slowed down the growth of solar energy?

answers: text: the 1970s
question: When was the interest in solar energy restored?

context: Solar hot water systems use sunlight to heat water. In low geographical latitudes (below 40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C 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.
qas: answers: text: 70
question: According to Shuman, up to what percentage of domestic hot water can be  provided by solar heating systems?

answers: text: sunlight
question: What do Solar hot water systems use to heat water?

answers: text: 60 to 70% of the domestic hot water
question: How much hot water can be produced by solar heating systems in low geographical latitudes?

answers: text: evacuated tube collectors
question: What is a common type of solar water heater?

answers: text: unglazed plastic collectors
question: What type of solar water heater is used to heat pools?

context: As of 2007, the total installed capacity of solar hot water systems is approximately 154 thermal gigawatt (GWth). China is the world leader in their deployment with 70 GWth installed as of 2006 and a long-term goal of 210 GWth by 2020. 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 is the dominant application of solar hot water with an installed capacity of 18 GWth as of 2005.
qas: answers: text: 154
question: What was the total capacity of solar hot water systems in 2007 in gigawatts?

answers: text: Israel and Cyprus
question: Over 90% of homes use solar hot water systems in which two countries?

answers: text: approximately 154 thermal gigawatt
question: What is the capacity of a solar hot water system?

answers: text: China
question: What country is the leader in the implementation of solar powered hot water systems?

answers: text: over 90%
question: What percentage of households use solar hot water systems in Israel and Cyprus?

answers: text: United States, Canada and Australia
question: In what countries is the use to solar hot water used mainly for w=swimming pools?

context: 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 a portion of this energy.
qas: answers: text: 50
question: What percentage of energy in commercial buildings comes from HVAC systems?

answers: text: 30% (4.65 EJ/yr)
question: How much energy does an HVAC system use in commercial locations?

answers: text: 50% (10.1 EJ/yr)
question: How much energy does an HVAC system use in residential locations?

answers: text: Solar heating, cooling and ventilation technologies
question: What can be used to balance out a portion of the energy used by HVAC systems?

context: 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 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 properly incorporated, thermal mass maintains space temperatures in a comfortable range and reduces the need for auxiliary heating and cooling equipment.
qas: answers: text: Thermal
question: Materials that can be used to store heat are known as what kind of mass?

answers: text: any material that can be used to store heat
question: What is thermal mass?

answers: text: stone, cement and water
question: What are typical thermal mass material?

answers: text: by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night
question: How is thermal mass used to keep buildings cool?

answers: text: climates
question: What is a something that determines the size of thermal mass?

answers: text: auxiliary heating and cooling equipment
question: What does thermal mass reduce the need for?

context: A solar chimney (or thermal chimney, in this context) 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.
qas: answers: text: passive solar ventilation
question: What kind of system is a solar chimney?

answers: text: a passive solar ventilation system
question: What is a solar chimney?

answers: text: a vertical shaft connecting the interior and exterior of a building
question: What is a solar chimney made of?

answers: text: by using glazing and thermal mass materials in a way that mimics greenhouses
question: How can the performance of a solar chimney be improved?

context: Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on 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 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.
qas: answers: text: winter
question: The placement of deciduous trees on the Equator facing side of a building can have a negative effect on solar availability in which season?

answers: text: trees and plants
question: What is something that is used to control solar heating and cooling?

answers: text: 1/3 to 1/2
question: How much solar radiation is blocked by leafless trees?

answers: text: they will interfere with winter solar availability
question: Why should trees not be planted on the side of a building facing the equator?

answers: text: east and west
question: What side of a building should trees be planted without greatly affecting solar gain in the winter?

context: 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 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 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.
qas: answers: text: 1767
question: Horace de Saussure built the first box cooker in what year?

answers: text: 315
question: Reflector cookers can reach temperatures in Celsius of up to what?

answers: text: cooking, drying and pasteurization
question: What are solar cookers used for?

answers: text: box cookers, panel cookers and reflector cookers
question: What are the 3 main categories of solar cookers?

answers: text: Horace de Saussure
question: Who created the box cooker?

answers: text: 90–150 °C (194–302 °F)
question: What is the typical temperature range for a box cooker?

answers: text: direct light
question: What do reflector cookers require to function?

context: 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, USA where 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 sea water 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 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 m2 (9,300 sq ft) collector in Costa Rica used for drying coffee beans and a 1,300 m2 (14,000 sq ft) collector in Coimbatore, India, used for drying marigolds.
qas: answers: text: 114
question: The Solar Total Energy Project had a field of how many parabolic dishes?

answers: text: more
question: Are transpired collectors more or less cost-effective than glazed collection systems?

answers: text: parabolic dish, trough and Scheffler reflectors
question: What are some examples of solar concentrating technologies?

answers: text: Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA
question: What was the first commercial solar concentrating system?

answers: text: use of evaporation ponds to obtain salt from sea water
question: What is one of the oldest uses of solar energy?

answers: text: Clothes lines, clotheshorses, and clothes racks
question: What are some items used to dry clothes without the use of electricity?

answers: text: perforated sun-facing walls used for preheating ventilation air
question: What are Unglazed transpired collectors?

context: 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 m2 (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 the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.
qas: answers: text: 1872
question: In what year was a large scale solar distillation project constructed in Las Salinas?

answers: text: Solar distillation
question: What is used to make saline or brackish water drinkable?

answers: text: 16th-century Arab alchemists
question: By who was the first record of solar distillation done by?

answers: text: 1872
question: When was the first large solar distillation plant created?

answers: text: 22,700 L (5,000 imp gal; 6,000 US gal) per day
question: How much water was produced by the plant?

answers: text: single-slope
question: What is an example of a solar distillation design?

context: 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 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.
qas: answers: text: the World Health Organization
question: Solar water disinfection is recommended by which organization?

answers: text: a minimum of six hours to two days during fully overcast conditions
question: How long should the plastic bottles filled with water be exposed to sunlight during Solar water disinfection?

answers: text: a viable method for household water treatment and safe storage
question: What does the World Health Organization say about Solar water disinfection?

answers: text: Over two million people in developing countries
question: How many people use Solar water disinfection to disinfect their drinking water?

context: Solar energy may be used in a water stabilisation 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 the water unusable.
qas: answers: text: toxic chemicals
question: What is a possible negative effect of algae in water stabilization ponds?

answers: text: to treat waste water without chemicals or electricity
question: For what reason would solar energy be used in a water stabilisation pond?

answers: text: algae may produce toxic chemicals
question: What is a reason why the water from a water stabilisation pond may be unusable?

context: Solar power is anticipated to become the world's largest source of electricity by 2050, with solar photovoltaics and concentrated solar power contributing 16 and 11 percent to the global overall consumption, respectively.
qas: answers: text: 2050
question: By what year is solar power expected to become the world's greatest source of electricity?

answers: text: 2050
question: When is solar power is foreseen to become the largest source of electricity?

context: Commercial CSP plants were first developed in the 1980s. Since 1985 the eventually 354 MW SEGS CSP installation, in the Mojave Desert of California, is the largest solar power plant in the world. Other large CSP plants include the 150 MW Solnova Solar Power Station and the 100 MW Andasol solar power station, both in Spain. The 250 MW Agua Caliente Solar Project, in the United States, and the 221 MW Charanka Solar Park in India, are the world’s largest photovoltaic plants. Solar projects exceeding 1 GW are being developed, but most of the deployed photovoltaics are in small rooftop arrays of less than 5 kW, which are grid connected using net metering and/or a feed-in tariff. In 2013 solar generated less than 1% of the worlds total grid electricity.
qas: answers: text: the Mojave Desert
question: The largest solar power plant in the world is located in what desert?

answers: text: 2013
question: Less than 1% of the world's total grid electricity was generated by solar energy in what year?

answers: text: 354 MW SEGS CSP
question: What is the largest solar power plant in the world?

answers: text: Mojave Desert of California
question: Where is the largest solar power plant in the world located?

answers: text: The 250 MW Agua Caliente Solar Project, in the United States, and the 221 MW Charanka Solar Park in India
question: What are the largest photovoltaic solar power plants?

context: In the last two decades, photovoltaics (PV), also known as solar PV, has evolved from a pure niche market of small scale applications towards becoming a mainstream electricity source. A solar cell is a device that converts light directly into electricity using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. In 1931 a German engineer, Dr Bruno Lange, developed a photo cell using silver selenide in place of copper oxide. Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the crystalline silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4.5–6%. By 2012 available efficiencies exceed 20% and the maximum efficiency of research photovoltaics is over 40%.
qas: answers: text: Charles Fritts
question: In the 1880s, who constructed the first solar cell?

answers: text: 1954
question: In what year was the crystalline silicon solar cell constructed?

answers: text: evolved from a pure niche market of small scale applications towards becoming a mainstream electricity source
question: What has happened to photovoltaic in the past 20 years?

answers: text: a device that converts light directly into electricity
question: What is a solar cell?

answers: text: Charles Fritts
question: Who created the first solar cell?

answers: text: Dr Bruno Lange
question: Who created the first solar cell using silver selenide in place of copper oxide?

answers: text: Gerald Pearson, Calvin Fuller and Daryl Chapin
question: Who created the crystalline silicon solar cell?

context: 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; the most developed are the parabolic trough, the concentrating linear fresnel reflector, the Stirling dish and the solar power tower. 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.
qas: answers: text: a working fluid
question: In all the different CSP systems, concentrated sunlight is used to heat what?

answers: text: lenses or mirrors and tracking systems
question: What do Concentrating Solar Power systems use?

answers: text: a heat source for a conventional power plant
question: What is the heat generated from a Concentrating Solar Power system used for?

answers: text: the Stirling dish
question: What is one of the most developed Concentrating Solar Power technologies?

answers: text: a working fluid is heated by the concentrated sunlight
question: What do Concentrating Solar Power technologies have in common?

context: 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 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.
qas: answers: text: Megaron House
question: Socrate's what is a classic example of passive solar design?

answers: text: orientation relative to the Sun
question: What is a common feature of passive solar architecture?

answers: text: well-lit spaces that stay in a comfortable temperature range
question: What is produced when the features of passive solar architecture are customized to the environment?

answers: text: Socrates' Megaron House
question: What is an example of passive solar design?

answers: text: pumps, fans and switchable windows
question: What kind of equipment can improve system performance?

context: Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures are a result of increased absorption of the Solar light 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 plant trees. 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.
qas: answers: text: Urban heat islands
question: UHI is an abbreviation of what?

answers: text: 3
question: A program in Los Angeles believes that with $1 billion, city temperatures could be reduced by approximately how many degrees in Celsius?

answers: text: Urban heat islands
question: What are the metropolitan areas with higher temperatures than the surrounding areas called?

answers: text: asphalt and concrete
question: What materials absorb sunlight and create higher temperatures than natural materials?

answers: text: paint buildings and roads white and plant trees
question: What is a way to reduce the high temperatures created in urban heat islands?

context: Agriculture and horticulture seek to optimize the capture of solar energy in order 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 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 the technology has been embraced by vinters, who use the energy generated by solar panels to power grape presses.
qas: answers: text: fruit walls
question: During the Little Ice Age, what did English and French farmers use to increase collection of solar energy?

answers: text: power grape presses
question: Vinters have adopted solar technology to do what?

answers: text: to optimize the productivity of plants
question: Why do agriculture and horticulture seek to make the most use of the solar energy captured?

answers: text: timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties
question: What are some techniques used to improve crop production?

answers: text: employed fruit walls
question: What did French and English farmers do during the Little Ice Age to gain more solar energy?

answers: text: acted as thermal masses and accelerated ripening by keeping plants warm
question: What was the purpose of the fruit walls built by French and English farmers?

context: 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 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, and plastic transparent materials have also been used to similar effect in polytunnels and row covers.
qas: answers: text: Roman times
question: When were the first greenhouses used?

answers: text: the 16th
question: In what century were the first modern greenhouses constructed?

answers: text: convert solar light to heat
question: What do greenhouses do with solar energy?

answers: text: enabling year-round production and the growth (in enclosed environments) of specialty crops
question: What is one purpose of a greenhouse?

answers: text: produce cucumbers year-round for the Roman emperor Tiberius
question: What was one of the first uses of a greenhouse?

answers: text: Europe
question: Where were the first modern greenhouses built?

context: Development of a solar-powered car has been an engineering goal since the 1980s. The World Solar Challenge 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 the planned South African Solar Challenge are comparable competitions that reflect an international interest in the engineering and development of solar powered vehicles.
qas: answers: text: The World Solar Challenge
question: What is the name of the solar powered car race held every two years?

answers: text: 90.87
question: What was the winner of the World Solar Challenge's average speed in 2007 in km/h?

answers: text: a biannual solar-powered car race
question: What is The World Solar Challenge?

answers: text: 1987
question: When was The World Solar Challenge started?

answers: text: 67 kilometres per hour (42 mph)
question: What was the average speed of a winning solar powered car in 1987?

answers: text: 90.87 kilometres per hour (56.46 mph)
question: What was the average speed of a winning solar powered car by 2007?

answers: text: The North American Solar Challenge and the planned South African Solar Challenge
question: What are some other similar car races that use solar powered vehicles?

context: 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 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.
qas: answers: text: 1975
question: The first practical solar boat was constructed in what year?

answers: text: 1975
question: When was the first solar powered boat made?

answers: text: Kenichi Horie
question: Who first crossed the Pacific ocean using a solar powered boat?

answers: text: the sun21 catamaran
question: What was the name of the first solar powered boat that crossed the Atlantic ocean?

context: In 1974, the unmanned AstroFlight Sunrise plane 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 feet (12 m). In 1980, 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 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. As of 2015, Solar Impulse, an electric aircraft, is currently circumnavigating the globe. It is a single-seat plane powered by solar cells and capable of taking off under its own power. The designed allows the aircraft to remain airborne for 36 hours.
qas: answers: text: 40
question: What altitude did the Solar Riser reach in feet?

answers: text: Solar Impulse
question: What is the name of the aircraft circling the globe in 2015 via solar power?

answers: text: 1974
question: When was the first unmanned flight by a solar powered plane made?

answers: text: 29 April 1979
question: When was the first solar powered manned flight made?

answers: text: July 1981
question: When did the Solar Challenger cross the English Channel?

answers: text: California to North Carolina
question: Where did Eric Scott Raymond fly using a solar powered plane in 1990?

answers: text: 36 hours
question: How long is the solar powered plane Solar Impulse able to remain in the air?

context: 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 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 sea water providing hydrogen to be run through adjacent fuel-cell electric power plants and the pure water by-product going directly into the municipal water system. Another vision involves all human structures covering the earth's surface (i.e., roads, vehicles and buildings) doing photosynthesis more efficiently than plants.
qas: answers: text: hydrogen production from protons
question: What is a possible alternative to making carbon-based fuels from reduction of carbon dioxide?

answers: text: Solar chemical processes
question: What process converts solar energy into storable and transportable fuels?

answers: text: artificial photosynthesis
question: What solar process can be used to produce different fuels?

context: Hydrogen production technologies 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 the heat from solar concentrators to drive the steam reformation of natural gas thereby increasing the overall hydrogen yield compared to conventional reforming methods. Thermochemical cycles characterized by the decomposition and regeneration of reactants present another avenue for hydrogen production. The Solzinc process under development at the Weizmann Institute uses a 1 MW solar furnace to decompose zinc oxide (ZnO) at temperatures above 1,200 °C (2,200 °F). This initial reaction produces pure zinc, which can subsequently be reacted with water to produce hydrogen.
qas: answers: text: The Solzinc process
question: What is the name of the process under development at the Weizmann Institute?

answers: text: pure zinc
question: The Solznic process produces what?

answers: text: Hydrogen production technologies
question: What has been a main area of solar chemical research since the 1970s?

answers: text: uses concentrators to split water into oxygen and hydrogen at high temperatures
question: What is one of the thermochemical processes that has been explored besides electrolysis?

answers: text: Solzinc process
question: What is the name of the process being developed by the Weizmann Institute?

context: Thermal mass systems can store solar energy in the form of heat at domestically useful temperatures for daily or interseasonal durations. Thermal storage systems generally use readily available materials with high specific heat capacities such as water, earth and stone. Well-designed systems can lower peak demand, shift time-of-use to off-peak hours and reduce overall heating and cooling requirements.
qas: answers: text: heat
question: In what form do thermal mass systems store solar energy?

answers: text: Thermal mass systems
question: What is the system called that can store solar energy in the form of heat?

answers: text: water, earth and stone
question: What are some of the materials used in thermal storage systems?

answers: text: reduce overall heating and cooling requirements
question: What is something that can be accomplished by a thermal mass system?

context: Phase change materials such as paraffin wax and Glauber's salt are another thermal storage media. These materials are inexpensive, readily available, and can deliver domestically useful temperatures (approximately 64 °C or 147 °F). The "Dover House" (in Dover, Massachusetts) was the first to use a Glauber's salt heating system, in 1948. Solar energy can also be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. The Solar Two used this method of energy storage, allowing it to store 1.44 terajoules (400,000 kWh) in its 68 cubic metres storage tank with an annual storage efficiency of about 99%.
qas: answers: text: thermal
question: Paraffin wax is an example of what kind of storage media?

answers: text: The "Dover House"
question: The first Glauber's salt heating system was first used where?

answers: text: paraffin wax and Glauber's salt
question: What are some examples of phase change materials?

answers: text: 64 °C or 147 °F
question: What are the approximate temperatures that can be delivered by phase change materials?

answers: text: Dover House
question: What was the name of the heating system that first used Glauber's salt?

answers: text: they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems
question: Why are salts good  for thermal storage?

answers: text: 1.44 terajoules (400,000 kWh)
question: How much energy was the Solar Two able to store using salts?

context: Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid, while standard grid electricity can be used to meet shortfalls. Net metering programs give household systems a credit for any electricity they deliver to the grid. This is handled by 'rolling back' the meter whenever the home produces more electricity than it consumes. If the net electricity use is below zero, the utility then rolls over the kilowatt hour credit to the next month. Other approaches involve the use of two meters, to measure electricity consumed vs. electricity produced. This is less common due to the increased installation cost of the second meter. Most standard meters accurately measure in both directions, making a second meter unnecessary.
qas: answers: text: rechargeable batteries
question: Where do off-grid PV systems store excess electricity?

answers: text: rechargeable batteries
question: What do off-grid PV systems use to store excess electricity?

answers: text: Net metering programs
question: What are the programs that gives credit to households for delivering electricity to the grid called?

answers: text: by 'rolling back' the meter whenever the home produces more electricity than it consumes
question: How is the credit to households accomplished?

answers: text: Most standard meters accurately measure in both directions
question: Why is a second meter usually unnecessary to monitor electricity use?

context: Pumped-storage hydroelectricity stores energy in the form of water pumped when energy is available from a lower elevation reservoir to a higher elevation one. The energy is recovered when demand is high by releasing the water, with the pump becoming a hydroelectric power generator.
qas: answers: text: a hydroelectric power generator
question: When water is released due to high demand, the pump become swhat?

answers: text: water pumped when energy is available from a lower elevation reservoir to a higher elevation one
question: Pumped-storage hydroelectricity stores energy in what form?

answers: text: by releasing the water, with the pump becoming a hydroelectric power generator
question: How is the energy stored by pumped-storage hydroelectricity recovered?

context: The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies. Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for Solar Energy Systems ISE).
qas: answers: text: 1973
question: The oil embargo in what year was a contributing factor to the reorganization of energy policies?

answers: text: The 1973 oil embargo and 1979 energy crisis
question: What brought attention to solar technologies in the 1970s?

answers: text: the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan
question: What are the names of some of the incentive programs used to promote solar technology?

answers: text: SERI, now NREL
question: What is the name of the solar energy research facility in the US?

answers: text: NEDO
question: What is the name of the solar energy research facility in Japan?

answers: text: Fraunhofer Institute for Solar Energy Systems ISE
question: What is the name of the solar energy research facility in Germany?

context: Commercial solar water heaters began appearing in the United States in the 1890s. These systems saw increasing use until the 1920s but were gradually replaced by cheaper and more reliable heating fuels. As with photovoltaics, solar water heating attracted renewed attention as a result of the oil crises in the 1970s but interest subsided in the 1980s due to falling petroleum prices. Development in the solar water heating sector progressed steadily throughout the 1990s and growth rates have averaged 20% per year since 1999. Although generally underestimated, solar water heating and cooling is by far the most widely deployed solar technology with an estimated capacity of 154 GW as of 2007.
qas: answers: text: the 1920s
question: The solar water heaters introduced in the US in the 1890s saw growth until what time period?

answers: text: 20% per year
question: Since 1999, what average rate has the solar water heating sector progressed at?

answers: text: in the 1890s
question: When did the use of solar water heaters in the US first begin?

answers: text: falling petroleum prices
question: Why did interest in solar water heating decrease in the 1980s?

answers: text: 20%
question: Growth of solar water heating development has averaged how much per year since 1999

answers: text: 154 GW
question: What was the estimated capacity of solar water heating and cooling in 2007?

context: The International Energy Agency has said that solar energy can make considerable contributions to solving some of the most urgent problems the world now faces:
qas: answers: text: The International Energy Agency
question: Which organization believes that solar energy can solve some of our most pressing issues?

answers: text: The International Energy Agency
question: Who said that solar energy can help solve some of the most urgent problems in the world?

context: The International Organization for Standardization has established a number of standards relating to solar energy equipment. For example, ISO 9050 relates to glass in building while ISO 10217 relates to the materials used in solar water heaters.
qas: answers: text: glass in building
question: ISO 9050 relates to standards for what?

answers: text: materials used in solar water heaters
question: ISO 10217 relates to standards for what?

answers: text: ISO 9050
question: What is the name of the standard related to glass in building?

answers: text: ISO 10217
question: What is the name of the standard related to the materials used in solar water heaters?

context: It is an important source of renewable energy and its technologies are broadly characterized as either passive solar or active solar depending on the way 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.
qas: answers: text: passive solar or active solar
question: What are the technologies used to capture solar energy characterized as?

answers: text: photovoltaic systems, concentrated solar power and solar water heating
question: What are some active solar techniques used to harness solar energy?

answers: text: orienting a building to the Sun
question: What is an example of a passive solar technique?

context: The large magnitude of solar energy available makes it a highly appealing source of electricity. The United Nations Development Programme in its 2000 World Energy Assessment found that the annual potential of solar energy was 1,575–49,837 exajoules (EJ). This is several times larger than the total world energy consumption, which was 559.8 EJ in 2012.
qas: answers: text: 559.8 EJ
question: What was the total worldwide energy consumption in 2012?

answers: text: 1,575–49,837 exajoules (EJ)
question: What is solar energy's yearly potential?

answers: text: The large magnitude of solar energy available
question: What makes solar energy an appealing source of electricity>

answers: text: The United Nations Development Programme
question: Who estimated the annual potential of solar energy in 2000?

context: 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 the costs of mitigating global warming, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared".
qas: answers: text: through reliance on an indigenous, inexhaustible and mostly import-independent resource
question: How will solar energy increase energy security?

answers: text: the costs of mitigating global warming
question: What costs will solar energy lower?

answers: text: learning investments
question: What should the cost of incentives for producing solar energy be considered?

answers: text: keep fossil fuel prices lower than otherwise
question: What effect will solar energy have on the price of fossil fuels?

context: The potential solar energy that could be used by humans differs from 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 limits the amount of solar energy that we can acquire.
qas: answers: text: geography, time variation, cloud cover, and the land available to humans
question: Why does the amount of usable solar energy differ from the amount near the planets surface?

context: Geography effects solar energy potential because areas that are closer to the equator have a greater amount of solar radiation. However, the use of photovoltaics that can follow the position of the sun can significantly increase the solar energy potential in areas that are farther from the equator. Time variation effects the potential of solar energy because during the nighttime there is little solar radiation on the surface of the Earth for solar panels to absorb. This limits the amount of energy that solar panels can absorb in one day. Cloud cover can effect the potential of solar panels because clouds block incoming light from the sun and reduce the light available for solar cells.
qas: answers: text: areas that are closer to the equator have a greater amount of solar radiation
question: Why does geography have an effect of the amount of solar energy available?

answers: text: photovoltaics
question: What is the process called that can increase solar energy in areas further away from the earth's equator?

answers: text: during the nighttime there is little solar radiation on the surface of the Earth for solar panels to absorb
question: Why does time have an effect of the amount of available solar energy?

answers: text: clouds block incoming light from the sun and reduce the light available for solar cells
question: What effect does cloud coverage have on the amount of solar energy available?

context: In addition, land availability has a large effect on the available solar energy because solar panels can only be set up on land that is unowned and suitable for solar panels. Roofs have been found to be a suitable place for solar cells, as many people have discovered that they can collect energy directly from their homes this way. Other areas that are suitable for solar cells are lands that are unowned by businesses where solar plants can be established.
qas: answers: text: solar panels can only be set up on land that is unowned and suitable for solar panels
question: Why does land availability have an effect on solar energy?

answers: text: many people have discovered that they can collect energy directly from their homes this way
question: Why are roofs a good place for solar panels?

context: 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 that took into account factors such as insolation, cloud cover, and the land that is usable by humans. The estimate found that solar energy has a global potential of 1,575–49,837 EJ per year (see table below).
qas: answers: text: insolation, cloud cover, and the land that is usable by humans
question: What factors were taken into account in the estimate published in 2000 on solar energy?

answers: text: 1,575–49,837 EJ per year
question: What was the total potential of solar energy found in the estimate?

context: Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the photoelectric effect.
qas: answers: text: conversion of sunlight into electricity
question: What is solar power?

answers: text: either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP)
question: How is sunlight converted into electricity?

answers: text: lenses or mirrors and tracking systems
question: What does a concentrated solar power system use?

answers: text: focus a large area of sunlight into a small beam
question: What is the purpose of a concentrated solar power system?

answers: text: photoelectric effect
question: What method does the photovoltaics system use to turn light into electricity?

context: 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 the south to provide light and warmth.
qas: answers: text: Sunlight
question: What has influenced the design since the beginning of architectural history?

answers: text: Greeks and Chinese
question: Who first utilized solar architecture?

answers: text: toward the south
question: In which direction were the buildings built by the Greeks and Chinese facing?

context: 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 is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high.
qas: answers: text: a black balloon that is filled with ordinary air
question: What is a solar balloon?

answers: text: the air inside is heated and expands causing an upward buoyancy force
question: What happens when sunlight shines on a solar balloon?

answers: text: the toy market
question: What is the use of solar balloons typically limited to?

answers: text: the surface-area to payload-weight ratio is relatively high
question: Why is the use of solar balloons typically limited to the toy market?

context: Beginning with the surge in coal use which accompanied the Industrial Revolution, energy consumption has steadily transitioned from wood and biomass to fossil fuels. The early development of solar technologies starting in the 1860s was driven by an expectation that coal would soon become scarce. However, development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum.
qas: answers: text: driven by an expectation that coal would soon become scarce
question: Why was solar technology developed in the 1860s?

answers: text: increasing availability, economy, and utility of coal and petroleum
question: What slowed the development of solar technologies in the early 20th century?

context: In 2011, a report by the International Energy Agency found that solar energy technologies such as photovoltaics, solar hot water and concentrated solar power could provide a third of the world’s energy by 2060 if politicians commit to limiting climate change. The energy from the sun could play a key role in de-carbonizing the global economy alongside improvements in energy efficiency and imposing costs on greenhouse gas emitters. "The strength of solar is the incredible variety and flexibility of applications, from small scale to big scale".
qas: answers: text: 2060
question: According to a report in 2011, by what year could solar energy provide a third of the world's energy?

answers: text: could play a key role in de-carbonizing the global economy alongside improvements in energy efficiency and imposing costs on greenhouse gas emitters
question: What could the sun's energy do to help limit climate change?