romikgosai/squad_modified huggingface dataset:
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.

Questions and answers:
['
Q: According to Shuman, up to what percentage of domestic hot water can be  provided by solar heating systems?
A: 70', '
Q: What do Solar hot water systems use to heat water?
A: sunlight', '
Q: How much hot water can be produced by solar heating systems in low geographical latitudes?
A: 60 to 70% of the domestic hot water', '
Q: What is a common type of solar water heater?
A: evacuated tube collectors', '
Q: What type of solar water heater is used to heat pools?
A: unglazed plastic collectors']
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.

Questions and answers:
['
Q: What was the total capacity of solar hot water systems in 2007 in gigawatts?
A: 154', '
Q: Over 90% of homes use solar hot water systems in which two countries?
A: Israel and Cyprus', '
Q: What is the capacity of a solar hot water system?
A: approximately 154 thermal gigawatt', '
Q: What country is the leader in the implementation of solar powered hot water systems?
A: China', '
Q: What percentage of households use solar hot water systems in Israel and Cyprus?
A: over 90%', '
Q: In what countries is the use to solar hot water used mainly for w=swimming pools?
A: United States, Canada and Australia']
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.

Questions and answers:
['
Q: What percentage of energy in commercial buildings comes from HVAC systems?
A: 50', '
Q: How much energy does an HVAC system use in commercial locations?
A: 30% (4.65 EJ/yr)', '
Q: How much energy does an HVAC system use in residential locations?
A: 50% (10.1 EJ/yr)', '
Q: What can be used to balance out a portion of the energy used by HVAC systems?
A: Solar heating, cooling and ventilation technologies']
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.

Questions and answers:
['
Q: Materials that can be used to store heat are known as what kind of mass?
A: Thermal', '
Q: What is thermal mass?
A: any material that can be used to store heat', '
Q: What are typical thermal mass material?
A: stone, cement and water', '
Q: How is thermal mass used to keep buildings cool?
A: by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night', '
Q: What is a something that determines the size of thermal mass?
A: climates', '
Q: What does thermal mass reduce the need for?
A: auxiliary heating and cooling equipment']
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.

Questions and answers:
['
Q: What kind of system is a solar chimney?
A: passive solar ventilation', '
Q: What is a solar chimney?
A: a passive solar ventilation system', '
Q: What is a solar chimney made of?
A: a vertical shaft connecting the interior and exterior of a building', '
Q: How can the performance of a solar chimney be improved?
A: 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 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.

Questions and answers:
['
Q: The placement of deciduous trees on the Equator facing side of a building can have a negative effect on solar availability in which season?
A: winter', '
Q: What is something that is used to control solar heating and cooling?
A: trees and plants', '
Q: How much solar radiation is blocked by leafless trees?
A: 1/3 to 1/2', '
Q: Why should trees not be planted on the side of a building facing the equator?
A: they will interfere with winter solar availability', '
Q: What side of a building should trees be planted without greatly affecting solar gain in the winter?
A: east and west']
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.

Questions and answers:
['
Q: Horace de Saussure built the first box cooker in what year?
A: 1767', '
Q: Reflector cookers can reach temperatures in Celsius of up to what?
A: 315', '
Q: What are solar cookers used for?
A: cooking, drying and pasteurization', '
Q: What are the 3 main categories of solar cookers?
A: box cookers, panel cookers and reflector cookers', '
Q: Who created the box cooker?
A: Horace de Saussure', '
Q: What is the typical temperature range for a box cooker?
A: 90–150 °C (194–302 °F)', '
Q: What do reflector cookers require to function?
A: direct light']
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.

Questions and answers:
['
Q: The Solar Total Energy Project had a field of how many parabolic dishes?
A: 114', '
Q: Are transpired collectors more or less cost-effective than glazed collection systems?
A: more', '
Q: What are some examples of solar concentrating technologies?
A: parabolic dish, trough and Scheffler reflectors', '
Q: What was the first commercial solar concentrating system?
A: Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA', '
Q: What is one of the oldest uses of solar energy?
A: use of evaporation ponds to obtain salt from sea water', '
Q: What are some items used to dry clothes without the use of electricity?
A: Clothes lines, clotheshorses, and clothes racks', '
Q: What are Unglazed transpired collectors?
A: perforated sun-facing walls used for preheating ventilation air']
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.

Questions and answers:
['
Q: In what year was a large scale solar distillation project constructed in Las Salinas?
A: 1872', '
Q: What is used to make saline or brackish water drinkable?
A: Solar distillation', '
Q: By who was the first record of solar distillation done by?
A: 16th-century Arab alchemists', '
Q: When was the first large solar distillation plant created?
A: 1872', '
Q: How much water was produced by the plant?
A: 22,700 L (5,000 imp gal; 6,000 US gal) per day', '
Q: What is an example of a solar distillation design?
A: single-slope']
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.

Questions and answers:
['
Q: Solar water disinfection is recommended by which organization?
A: the World Health Organization', '
Q: How long should the plastic bottles filled with water be exposed to sunlight during Solar water disinfection?
A: a minimum of six hours to two days during fully overcast conditions', '
Q: What does the World Health Organization say about Solar water disinfection?
A: a viable method for household water treatment and safe storage', '
Q: How many people use Solar water disinfection to disinfect their drinking water?
A: Over two million people in developing countries']
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.

Questions and answers:
['
Q: What is a possible negative effect of algae in water stabilization ponds?
A: toxic chemicals', '
Q: For what reason would solar energy be used in a water stabilisation pond?
A: to treat waste water without chemicals or electricity', '
Q: What is a reason why the water from a water stabilisation pond may be unusable?
A: algae may produce toxic chemicals']
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.

Questions and answers:
["
Q: By what year is solar power expected to become the world's greatest source of electricity?
A: 2050", '
Q: When is solar power is foreseen to become the largest source of electricity?
A: 2050']
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.

Questions and answers:
['
Q: The largest solar power plant in the world is located in what desert?
A: the Mojave Desert', "
Q: Less than 1% of the world's total grid electricity was generated by solar energy in what year?
A: 2013", '
Q: What is the largest solar power plant in the world?
A: 354 MW SEGS CSP', '
Q: Where is the largest solar power plant in the world located?
A: Mojave Desert of California', '
Q: What are the largest photovoltaic solar power plants?
A: The 250 MW Agua Caliente Solar Project, in the United States, and the 221 MW Charanka Solar Park in India']
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%.

Questions and answers:
['
Q: In the 1880s, who constructed the first solar cell?
A: Charles Fritts', '
Q: In what year was the crystalline silicon solar cell constructed?
A: 1954', '
Q: What has happened to photovoltaic in the past 20 years?
A: evolved from a pure niche market of small scale applications towards becoming a mainstream electricity source', '
Q: What is a solar cell?
A: a device that converts light directly into electricity', '
Q: Who created the first solar cell?
A: Charles Fritts', '
Q: Who created the first solar cell using silver selenide in place of copper oxide?
A: Dr Bruno Lange', '
Q: Who created the crystalline silicon solar cell?
A: Gerald Pearson, Calvin Fuller and Daryl Chapin']
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.

Questions and answers:
['
Q: In all the different CSP systems, concentrated sunlight is used to heat what?
A: a working fluid', '
Q: What do Concentrating Solar Power systems use?
A: lenses or mirrors and tracking systems', '
Q: What is the heat generated from a Concentrating Solar Power system used for?
A: a heat source for a conventional power plant', '
Q: What is one of the most developed Concentrating Solar Power technologies?
A: the Stirling dish', '
Q: What do Concentrating Solar Power technologies have in common?
A: a working fluid is heated by the concentrated sunlight']
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.

Questions and answers:
["
Q: Socrate's what is a classic example of passive solar design?
A: Megaron House", '
Q: What is a common feature of passive solar architecture?
A: orientation relative to the Sun', '
Q: What is produced when the features of passive solar architecture are customized to the environment?
A: well-lit spaces that stay in a comfortable temperature range', "
Q: What is an example of passive solar design?
A: Socrates' Megaron House", '
Q: What kind of equipment can improve system performance?
A: pumps, fans and switchable windows']
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.

Questions and answers:
['
Q: UHI is an abbreviation of what?
A: Urban heat islands', '
Q: A program in Los Angeles believes that with $1 billion, city temperatures could be reduced by approximately how many degrees in Celsius?
A: 3', '
Q: What are the metropolitan areas with higher temperatures than the surrounding areas called?
A: Urban heat islands', '
Q: What materials absorb sunlight and create higher temperatures than natural materials?
A: asphalt and concrete', '
Q: What is a way to reduce the high temperatures created in urban heat islands?
A: paint buildings and roads white and plant trees']
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.

Questions and answers:
['
Q: During the Little Ice Age, what did English and French farmers use to increase collection of solar energy?
A: fruit walls', '
Q: Vinters have adopted solar technology to do what?
A: power grape presses', '
Q: Why do agriculture and horticulture seek to make the most use of the solar energy captured?
A: to optimize the productivity of plants', '
Q: What are some techniques used to improve crop production?
A: timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties', '
Q: What did French and English farmers do during the Little Ice Age to gain more solar energy?
A: employed fruit walls', '
Q: What was the purpose of the fruit walls built by French and English farmers?
A: acted as thermal masses and accelerated ripening by keeping plants warm']
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.

Questions and answers:
['
Q: When were the first greenhouses used?
A: Roman times', '
Q: In what century were the first modern greenhouses constructed?
A: the 16th', '
Q: What do greenhouses do with solar energy?
A: convert solar light to heat', '
Q: What is one purpose of a greenhouse?
A: enabling year-round production and the growth (in enclosed environments) of specialty crops', '
Q: What was one of the first uses of a greenhouse?
A: produce cucumbers year-round for the Roman emperor Tiberius', '
Q: Where were the first modern greenhouses built?
A: Europe']