File Name: solar thermal power plant advantages and disadvantages .zip
Solar thermal energy STE is a form of energy and a technology for harnessing solar energy to generate thermal energy for use in industry , and in the residential and commercial sectors. Solar thermal collectors are classified by the United States Energy Information Administration as low-, medium-, or high-temperature collectors.
Low-temperature collectors are generally unglazed and used to heat swimming pools or to heat ventilation air. Medium-temperature collectors are also usually flat plates but are used for heating water or air for residential and commercial use. These plants employ a variety of different technologies. Spain is the other major developer of solar thermal power plant.
Augustin Mouchot demonstrated a solar collector with a cooling engine making ice cream at the Universal Exhibition in Paris. The first installation of solar thermal energy equipment occurred in the Sahara approximately in by Frank Shuman when a steam engine was run on steam produced by sunlight. Because liquid fuel engines were developed and found more convenient, the Sahara project was abandoned, only to be revisited several decades later. Systems for utilizing low-temperature solar thermal energy include means for heat collection; usually heat storage, either short-term or interseasonal; and distribution within a structure or a district heating network.
In some cases a single feature can do more than one of these things e. Some systems are passive, others are active requiring other external energy to function. Heating is the most obvious application, but solar cooling can be achieved for a building or for district cooling by using a heat-driven absorption or adsorption chiller heat pump.
There is a productive coincidence that the greater the driving heat from insolation, the greater the cooling output. In , Auguste Mouchout pioneered solar cooling by making ice using a solar steam engine attached to a refrigeration device. The most popular solar heating technology for heating buildings is the building integrated transpired solar air collection system which connects to the building's HVAC equipment.
According to Solar Energy Industries Association over , m 2 5,, square feet of these panels are in operation in North America as of The Solar District Heating program SDH has participation from 14 European Nations and the European Commission, and is working toward technical and market development, and holds annual conferences.
Glazed solar collectors are designed primarily for space heating. They recirculate building air through a solar air panel where the air is heated and then directed back into the building. These solar space heating systems require at least two penetrations into the building and only perform when the air in the solar collector is warmer than the building room temperature.
Most glazed collectors are used in the residential sector. Unglazed solar collectors are primarily used to pre-heat make-up ventilation air in commercial, industrial and institutional buildings with a high ventilation load. They turn building walls or sections of walls into low cost, high performance, unglazed solar collectors.
Also called, "transpired solar panels" or " solar wall ", they employ a painted perforated metal solar heat absorber that also serves as the exterior wall surface of the building. Heat transfer to the air takes place on the surface of the absorber, through the metal absorber and behind the absorber.
The boundary layer of solar heated air is drawn into a nearby perforation before the heat can escape by convection to the outside air. The heated air is then drawn from behind the absorber plate into the building's ventilation system. A Trombe wall is a passive solar heating and ventilation system consisting of an air channel sandwiched between a window and a sun-facing thermal mass. During the ventilation cycle, sunlight stores heat in the thermal mass and warms the air channel causing circulation through vents at the top and bottom of the wall.
During the heating cycle the Trombe wall radiates stored heat. Solar roof ponds for solar heating and cooling were developed by Harold Hay in the s. A basic system consists of a roof-mounted water bladder with a movable insulating cover. This system can control heat exchange between interior and exterior environments by covering and uncovering the bladder between night and day.
When heating is a concern the bladder is uncovered during the day allowing sunlight to warm the water bladder and store heat for evening use. When cooling is a concern the covered bladder draws heat from the building's interior during the day and is uncovered at night to radiate heat to the cooler atmosphere.
The Skytherm house in Atascadero, California uses a prototype roof pond for heating and cooling. Solar space heating with solar air heat collectors is more popular in the USA and Canada than heating with solar liquid collectors since most buildings already have a ventilation system for heating and cooling.
The two main types of solar air panels are glazed and unglazed. Collectors can use air or water as the medium to transfer the heat to their destination. A collection of mature technologies called seasonal thermal energy storage STES is capable of storing heat for months at a time, so solar heat collected primarily in Summer can be used for all-year heating. Solar-supplied STES technology has been advanced primarily in Denmark,  Germany,  and Canada,  and applications include individual buildings and district heating networks.
Centralized district heating round the clock is also feasible with concentrated solar thermal CST storage plant. Interseasonal storage. Solar heat or heat from other sources can be effectively stored between opposing seasons in aquifers , underground geological strata, large specially constructed pits, and large tanks that are insulated and covered with earth. Short-term storage. Thermal mass materials store solar energy during the day and release this energy during cooler periods.
Common thermal mass materials include stone, concrete, and water. The proportion and placement of thermal mass should consider several factors such as climate, daylighting, and shading conditions.
When properly incorporated, thermal mass can passively maintain comfortable temperatures while reducing energy consumption. It is a niche market because the economics are challenging, with the annual number of cooling hours a limiting factor.
Respectively, the annual cooling hours are roughly in the Mediterranean, in Southeast Asia, and only 50 to in Central Europe. A solar chimney or thermal chimney is a passive solar ventilation system composed of a hollow thermal mass 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.
These systems have been in use since Roman times and remain common in the Middle East. Solar process heating systems are designed to provide large quantities of hot water or space heating for nonresidential buildings. Evaporation ponds are shallow ponds 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. Altogether, evaporation ponds represent one of the largest commercial applications of solar energy in use today. Unglazed transpired collectors are perforated sun-facing walls used for preheating ventilation air. As of , over systems with a combined collector area of , m 2 had been installed worldwide. Representatives include an m 2 collector in Costa Rica used for drying coffee beans and a m 2 collector in Coimbatore, India used for drying marigolds.
A food processing facility in Modesto, California uses parabolic troughs to produce steam used in the manufacturing process. Labor for a simple open loop system in southern climates can take 3—5 hours for the installation and 4—6 hours in Northern areas. Northern system require more collector area and more complex plumbing to protect the collector from freezing. With this incentive, the payback time for a typical household is four to nine years, depending on the state. Similar subsidies exist in parts of Europe.
A crew of one solar plumber and two assistants with minimal training can install a system per day. European and International standards are being reviewed to accommodate innovations in design and operation of medium temperature collectors. Operational innovations include "permanently wetted collector" operation. This innovation reduces or even eliminates the occurrence of no-flow high temperature stresses called stagnation which would otherwise reduce the life expectancy of collectors.
Solar thermal energy can be useful for drying wood for construction and wood fuels such as wood chips for combustion. Solar is also used for food products such as fruits, grains, and fish.
Crop drying by solar means is environmentally friendly as well as cost effective while improving the quality. The less money it takes to make a product, the less it can be sold for, pleasing both the buyers and the sellers. Technologies in solar drying include ultra low cost pumped transpired plate air collectors based on black fabrics.
Solar thermal energy is helpful in the process of drying products such as wood chips and other forms of biomass by raising the temperature while allowing air to pass through and get rid of the moisture. Solar cookers use sunlight for cooking, drying and pasteurization. Solar cooking offsets fuel costs, reduces demand for fuel or firewood, and improves air quality by reducing or removing a source of smoke.
The simplest type of solar cooker is the box cooker first built by Horace de Saussure in A basic box cooker consists of an insulated container with a transparent lid. Concentrating solar cookers use reflectors to concentrate solar energy onto a cooking container. The most common reflector geometries are flat plate, disc and parabolic trough type. The Solar Kitchen in Auroville , India uses a unique concentrating technology known as the solar bowl.
Many other solar kitchens in India use another unique concentrating technology known as the Scheffler reflector. This technology was first developed by Wolfgang Scheffler in A Scheffler reflector is a parabolic dish that uses single axis tracking to follow the Sun's daily course. These reflectors have a flexible reflective surface that is able to change its curvature to adjust to seasonal variations in the incident angle of sunlight.
Solar stills can be used to make drinking water in areas where clean water is not common. Solar distillation is necessary in these situations to provide people with purified water.
Solar energy heats up the water in the still. The water then evaporates and condenses on the bottom of the covering glass.
Such temperatures are too low for efficient conversion to electricity. The efficiency of heat engines increases with the temperature of the heat source. The practical effect of high efficiencies is to reduce the plant's collector size and total land use per unit power generated, reducing the environmental impacts of a power plant as well as its expense. As the temperature increases, different forms of conversion become practical. Higher temperatures are problematic because different materials and techniques are needed.
High temperatures also make heat storage more efficient, because more watt-hours are stored per unit of fluid.
Solar thermal energy has been losing out in the last couple of years to solar photovoltaic energy which is seeing a huge increase in demand amidst very low prices. Some of the major solar thermal energy projects in the globe have been converted into solar PV installations due to its lower costs. Some of the major solar thermal energy companies like Solar Millennium have sold their solar thermal portfolios to other companies while Stirling Power Systems has gone bankrupt. Tessera has sold its solar thermal plants which had gotten DOE Loan Guarantees in California to Solar Developers who have made these solar thermal plants into solar panel ones. Their Power Tower Technologies are supposedly more efficient than the mainstream parabolic toughs that are used.
Advantages of Solar Energy. Renewable Energy Source. Among all the benefits of solar panels, the most important thing is that solar energy is a truly renewable energy source. Reduces Electricity Bills. Diverse Applications. Low Maintenance Costs. Technology Development. Cost. Weather-Dependent. Solar Energy Storage Is.
A thermal power station is a power station in which heat energy is converted to electricity. Typically, water is heated into steam, which is used to drive an electrical generator. After it passes through the turbine the steam is condensed in a steam condenser and recycled to where it was heated. This is known as a Rankine cycle.
Solar power is the conversion of the sun's energy into electricity. With an estimated , terawatts of solar energy continuously hitting Earth's surface 1 , there is more than enough energy to meet the world's current consumption levels of 15 terawatts per year 2. The trick, though, is collecting it. Solar energy is primarily collected in one of two ways: photovoltaic solar cells and solar thermal. A photovoltaic cell is basically a semi-conductor connected to two electrical contacts.
Depending on geographical location the size of the solar panels vary for the same power generation; Cloudy days do not produce as much.
Sunlight is a renewable energy source which can be converted into usable energy by solar panels. There are two main types of solar energy. Solar photovoltaic PV panels directly convert solar energy into a usable form of energy using a PV cell containing a semiconductor material. CSP concentrating solar power on the other hand, concentrate energy from sunlight to a heat receiver which transforms energy from heat into mechanical energy, and in turn, solar thermal electricity. If you are interested in reading about how Solar Energy is utilised in engineering applications, read this article on low power solenoid valves in a solar power application. Interested in receiving even more industry-leading news from Process Industry Forum delivered directly to your inbox?
I have been following a post on Wiki Answers for a while on the advantages and disadvantages to solar power and wanted to share the results. The discussion started a while ago and has had a lot of feedback. Here are the results. There is more solar power that hits the earth every day then the current population can use in a year. With efficiencies evolving, pricing being reduced every day, and new technologies being experimented with, it will be interesting to see where we are in the solar industry in the next couple years. What do you think the future will look like? Editor's Note: This post was originally published in January and has been completely revamped and updated for accuracy and comprehensiveness.
Пьер Клушар спал глубоким сном и не видел склонившегося над ним человека. Игла похищенного у медсестры шприца блеснула в темноте и погрузилась в вену чуть выше запястья Клушара. Шприц был наполнен тридцатью кубиками моющего средства, взятого с тележки уборщицы. Сильный палец нажал на плунжер, вытолкнув синеватую жидкость в старческую вену. Клушар проснулся лишь на несколько секунд.
Даже в полуметре от шефа она не видела очертаний его фигуры. Всякий раз, ступая на очередную ступеньку, она носком туфли первым делом старалась нащупать ее край. К ней снова вернулись страхи, связанные с новой попыткой найти ключ Хейла в Третьем узле. Коммандер был абсолютно убежден в том, что у Хейла не хватит духу на них напасть, но Сьюзан не была так уж уверена в .
Он вздохнул и задал единственный вопрос, который пришел ему в голову; - Как выглядит эта девушка. - Era un punqui, - ответила Росио.
Стоящая перед ним задача была крайне деликатна и требовала массу времени - вписать скрытый черный ход в сложный алгоритм и добавить невидимый ключ в Интернете. Тайна имела первостепенное значение. Любое подозрение об изменении Цифровой крепости могло разрушить весь замысел коммандера. Только сейчас она поняла, почему он настаивал на том, чтобы ТРАНСТЕКСТ продолжал работать. Если Цифровой крепости суждено стать любимой игрушкой АНБ, Стратмор хотел убедиться, что взломать ее невозможно.
Над их головами куполом раскинулось усыпанное звездами небо. Такие же звезды, наверное, видит сейчас Дэвид в небе над Севильей, подумала. Подойдя к тяжелой стеклянной двери, Стратмор еле слышно чертыхнулся.
Но сейчас только без четверти. Двухцветный посмотрел на часы Беккера.
Директор! - взорвался Джабба. - Когда эти стены рухнут, вся планета получит высший уровень допуска к нашим секретам. Высший уровень. К отчетам о секретных операциях. К зарубежной агентурной сети.
За пределами концентрических окружностей появились две тонкие линии. Они были похожи на сперматозоиды, стремящиеся проникнуть в неподатливую яйцеклетку. - Пора, ребята! - Джабба повернулся к директору. - Мне необходимо решение. Или мы начинаем отключение, или же мы никогда этого не сделаем.
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