Хибридни термоцентрали

4 Comments

1. 1

   

   Igor

   ноември 5, 2011 at 1:31 pm

   Не работат на жежок воздух, туку на одреден вид на фреон кој има карактеристика да испарува на пониска температура од водата.

   И овие централи немаат врска со „хибридни“, бидејќи хибридни значи да употребуваат два различни енергенси (горива).

   Во случајов се работи за еден енергент (гориво) – сончева енергија.

   Ова се сончеви термоцентрали (ја користат сончевата топлина за индиректно да произведат електрична енергија), а другиот вид се сончеви фотоволтажни централи (ја користат сончевата светлина за директно да произведат електрична енергија).

   1. 1.1

      

      Златко Чавдаровски

      ноември 5, 2011 at 4:14 pm

      Според Универзитетот од Тел Авив, кој го предлага овој концепт, сепак се работи за жежок ВОЗДУХ. И концептот Е хибриден, зашто се работи за комбинирано работење на класична термоцентрала со сончева термоцентрала. Сончевата централа во овој случај служи како поддршка на термоцентралата, за намалување на потрошувачката на фосилно гориво, од кое се добива жешкиот гас.

2. 2

   

   Dipl.El. Inz. MAKSIM

   ноември 28, 2011 at 4:04 am

   Pocituvani,

   Podolu vi isprakjam originalen materijal(za zal na angliski), za toa sto se i kako rabotat TERMO SOLARNI CENTRALI. Za vasa informacija , mislam deka veke se izrabotuva( so donacija od Francija) studija za moznosta i REK Bitola vo idnina da raboti kombinirano , na sonce i na jaglen.

   Pozdrav.

   ==============================================================

   Power generation

   Turning sunlight into electricity

   The International Energy Outlook 2010 projections, published by the United States Energy Information Administration, predicts a 49% increase in the total world consumption of marketed energy from 2007 to 2035. The escalating cost of fossil fuels, its availability, and environmental concerns, are forcing the world to find alternative sources of energy.

   The use of renewable resources to produce energy is a good option since they are clean, do not harm the envi-ronment, and are available in quantity. Solar energy is the most abundantly available source of energy on earth. The

   amount of solar radiation the earth receives in one hour equates to more energy than the world consumes in a year.

   The difficulty lies in collecting and transforming it into electricity. Converting sunlight, or sun heat, into electricity can be

   accomplished by two different technologies: photovoltaic or concentrating solar power (CSP). Both are effective ways to

   generate electricity and both are being developed rapidly.

   Concentrating solar power

   There are various methods of concentrating radiation from the sun in order to produce electricity. The sun heats a

   medium which heats water, directly or indirectly. The water produces steam through heat exchangers and it causes a

   conventional steam turbine generator to produce clean electricity. Linear Fresnel reflectors concentrate solar energy

   onto tubes housed in an elevated receiver. A parabolic trough consists of parabolic mirrors which track the sun and

   concentrate the solar energy onto receiver tubes placed in the trough’s focal line. These two technologies use synthetic

   oil as the heat transfer medium or heat transfer fluid (HTF) which flows in the tubes.Another technology is based on the

   central tower concept where a circular array of mirrors (heliostats) reflect the sun’s rays to a receiver on top of a tower

   were the heat is concentrated. The beam down system is similar in the use of a central tower and heliostats. The

   difference,however, is a reflector placed in the top of the tower that concentrates the light down to a receiver at ground

   level where the media is heated. Both of these methods use molten salt as the heat transfer medium and heat storage

   fluid. Although the use of parabolic troughs is a more developed technology, central tower appears to be the most

   efficient technology. One of the largest parabolic trough plants in the world is in California, generating 165 MW. Other

   large solar thermal power plants using parabolic troughs can be found in Spain, capable of delivering electricity to more

   than 500,000 homes.

   Heat storage system

   Every technology has its limitations, and CSP is no exception. The geographical area is an important factor because

   The sun’s rays penetrate the earth in different ways. But the most important limitation of solar technology, whether PV

   or CSP, is that the sun doesn’t shine all day, every day. Nights and cloudy days present an obstacle when generating

   electricity. An energy storage system is the answer to overcoming this limitation. The processes of this system can

   vary but there seems to be a preference for the use of hot and cold molten salt in conjunction with heat exchangers.

   Molten salt is a substance that stores thermal energy making it possible to transfer it and produce electricity when the

   sun is not shining.

   Reflectors and troughs

   When sunlight is available, the synthetic oil (HTF) is heated as it circulates through the troughs. From the troughs,

   some of the HTF goes to the HTF-water heat exchanger to produce steam which generates electricity, and some to

   the HTF-molten salt heat exchanger to heat the cold molten salt (See Figure 2). The heated molten salt is then

   stored in the hot tank. At night or on cloudy days, the hot molten salt is pumped to the molten salt-HTF heat exchanger

   heating the HTF, then on to the cold molten salt storage tank (where it is stored until the sun appearsand the process

   starts again). This way, the production of energy is continuous. Vertical pumps are required for the molten salt

   tanks, and horizontal pumps are used for the HTF process as shown in the image on the previous page.

   Central tower and beam down

   During days with ample sunlight, the molten salt is pumped from the cold tank through the receiver section where it

   absorbs heat from the concentrated sunlight reflected via the heliostats. After that, the heated molten salt flows to the

   hot tank. From the hot tank, another pump transfers the hot molten salt through a series of heat exchangers,

   thereby generating high-pressure steam and then electricity thanks to a conventional steam turbine generator. The

   cooler molten salt ends up back in the cold tank where it is ready to start the cycle anew.At night or on cloudy days, the

   largereservoir of heated molten salt in the heavily-insulated hot tank can be pumpedthrough the steam generator

   system. Using this method, electricity can be generated continuously throughout the night. The following morning, the

   molten salt will be back in the cold tank, ready to begin the solar heating cycle again. The molten sal pumps are vertical

   pumps and horizontal pumps are used in the power generation system. This process requires the molten salt to be

   pumped to the top of the central tower, which is costlier than pumping it to ground level, as is the case with the

   Beam Down method. What may be lost in horsepower may be overcompensated due to higher heat generation and

   efficiency.

   Centrifugal pumps in the process

   All of the technologies discussed here require pumps to re-circulate the HTF (synthetic oil), molten salt, and water/

   steam (within each respective loop). Pumps make it possible to generate clean electricity with conventional steam

   turbines. The following pumps offered by Ruhrpumpen are typically used for the varying applications. Due to the

   variable operation and the daily start-stop, the horizontal double suction, between bearings single stage pumps are

   used for pumping synthetic heat transfer oil. A chrome steel material for the casing and impellers is a good option when

   handling temperatures up to 400єC and pressures up to 40 bars. For pumping molten salt from the storage tank, either

   cold or hot, a vertical turbine pump is the right choice. Special materials are required in order to meet the temperature

   and pressure requirements. For the power generation section of the plant, multi-stage inbetween bearings horizontal

   pumps may be used for boiler feed water service, while vertical circulator mix-flow pumps may be used to

   move water through the cooling towers. In addition, vertical can pumps with low NPSH first stage impellers may be use

   for condensate service.

   1. 2.1

      

      Предраг Стојковски

      ноември 28, 2011 at 12:22 pm

      Здраво Максим,

      Пред се благодариме на тоа што не пратиш и на пратените материјали. Инаку, ДА веќе се изработува (или барем така најавија :)) студија финансирана од страна на Франција, за како што рековте и РЕК Битола работи комбинирано- сонце + јаглен.

      Срдачен поздрав и продолжите и понатаму да не пратите

      тимот на енергетска ефикасност

Comments are closed.