Solar thermal energy

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Solar thermal energy

• Eng. Elamir Ahmed

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Definition of solar thermal energy

• Solar thermal energy is a renewable energy
  source.
• Solar thermal uses technology to harness infrared
  energy from sunlight to capture and store heat.
  This stored heat is released later to warm water
  and air, or on an even larger scale, to generate
  steam which in turn powers a turbine.

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Types of solar thermal system

• Active solar thermal system
• Uses a pump, fan, or other powered device.
• Passive solar thermal system
• Does not use a pump or fan - relies on natural
  forces
• Gravity density.
• Indirect solar thermal system
• A heat exchanger is used to transfer heat.
• Example transfer heat from the circulating fluid
  to the city water.
• Direct solar thermal system
• Does not use a heat exchanger, direct heat
  transfer.
• Example City or potable water is circulated from
  the tank to the collector and back.

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Solar collectors

• Dark Surface with High Absorptance Gathers Full
  Spectrum of Solar Radiation.
• Glass and/or Selective Surface Used to Minimize
  Conduction and Re-radiation Losses.
• Efficiency Dependant on Collector Design and
  Working Temperature.

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Types of solar collectors
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Flat plate collectors

• Flat-plate collector is an insulated metal box
  with a glass or plastic cover (called the
  glazing) and a dark-colored absorber plate.
• These collectors heat liquid or air at
  temperatures less than 230F.

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evacuated tube collectors

• Evacuated-tube collectors are usually made of
  parallel rows of transparent glass tubes. Each
  tube contains a glass outer tube and metal
  absorber tube attached to a fin. The fin is
  covered with a coating that absorbs solar energy
  well, but which inhibits radiative heat loss. Air
  is removed, or evacuated, from the space between
  the two glass tubes to form a vacuum, which
  eliminates conductive and convective heat loss.
• The collectors can achieve high temperatures
  (230F to 300F), making them more appropriate
  for cooling, commercial and industrial
  applications. However, evacuated-tube collectors
  are more expensive than flat-plate collectors,
  with cost about twice that of flat-plate
  collectors.

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Concentrating collectors

• Concentrating collectors consist of parabolic and
  mirrored surfaces to concentrate and get sunlight
  energy.
• They are able to generate very high
  temperatures.
• They demand direct sunlight and do not perform
  well in climates with low levels of direct
  sunlight.

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Solar water heating

• One of the most cost-effective ways to include
  renewable technologies into a building is by
  incorporating solar hot water.
• Most solar water heating systems for buildings
  have two main parts (1) solar collector and (2)
  storage tank.
• The most common collector used in solar hot water
  systems is the flat-plate collector.
• Solar water heating systems can be either active
  or passive, but the most common are active
  systems.

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Solar pool heating

• The solar pool heating system uses the existing
  pool pump to circulate water through the solar
  collector where it is warmed by the sun.
• Applicable for Indoor or Outdoor Pools
• Highest Operating Efficiency

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Solar space heating

• A solar space-heating system can consist of
  passive system or active system.
• Passive systems are typically less costly and
  less complex than active systems.
• when retrofitting a building, active systems
  might be the only option for obtaining solar
  energy.

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Solar space Cooling (Solar Absorption System)

• Solar absorption system uses solar heat instead
  of electricity and compressor to drive the
  device.
• Solar absorption systems use solar heat to
  separate a mixture of absorbent and refrigerant
  fluids. Once separated, the refrigerant is
  condensed and evaporated to create a cooling
  effect. It is then reabsorbed to repeat the
  cycle.
• Solar space cooling systems are expensive and
  complicated to install and maintain.
• The great advantage is reduced energy bills.

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Solar absorption chiller
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Solar thermal power stationPower Tower

• Power Tower uses thousands of sun-tracking
  reflectors or heliostats to direct and
  concentrate solar radiation onto a boiler located
  atop a tower. The temperature in the boiler rises
  and the steam raised can be used to drive a
  turbine, which in turn drives an electric
  generator producing electricity.

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Solar cooking

• Solar cooking is a technology which has been
  given a lot of attention in recent years in
  developing countries.
• The basic design is that of a box with a glass
  cover. The box is lined with insulation and a
  reflective surface is applied to concentrate the
  heat onto the pots. The pots can be painted black
  to help with heat absorption. The solar radiation
  raises the temperature sufficiently to boil the
  contents in the pots.
• Cooking time is often a lot slower than
  conventional cooking stoves but there is no fuel
  cost.

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Day-lighting

• A simple and obvious use for solar energy is to
  provide light for use in buildings.
• The buildings are designed in such a way that the
  light of the sun can be used to provide
  sufficient light for the activities taking place
  within the building.
• The energy saving is significant and natural
  lighting is often preferred to artificial
  electric lighting.

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Solar thermal advantages

• Cost Effective
• Solar thermal systems can save you up to 60 of
  your costs. They offer the lowest cost of
  renewable energy technology.
• Easy installation
• Solar thermal systems can easily be installed and
  retrofitted to most buildings.
• Efficiency
• Solar thermal system is the most efficient use of
  renewable energy it's available when you need
  it, and it's a more effective solar collector -
  it even works in less sunny conditions.
• Return on Investment
• Solar thermal systems pay for themselves in as
  little as 5 years.
• Reliability
• Solar thermal systems are reliable and require
  little maintenance over their 25 year life.

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Energy costs and energy saving

• (solar thermal energy)

• (electrical energy)

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Thank you!!!!