Solar Thermal Market Overview

  • Solar Thermal energy is the harvesting of heat from the sun to be used as heat energy
  • Using heat as heat can be very cost-effective, especially at lower temperatures, compared to using electricity from solar PV to generate heat
  • Solar water heaters are the most familiar example of solar thermal, though applications range from cooking to air-conditioning
  • Global installations are greater than 270 GWth. Almost 80% is used for domestic water heating. Industrial process heat accounts for less than 1%

Solar Thermal Technology Overview

  • Low temperature – up to 70°C – Flat plate and Evacuated Tube Collectors
  • Medium temperature – 70-150°C – Enhanced Evacuated Tube, Compound Parabolic Concentrator
  • High temperature – above 150°C upto 250°CConcentrating Solar Thermal

Low Temperature Solar Thermal

  • Typical application is water heating. Air drying is a niche application in this temperature range.
  • Flat Plate Collectors (FTC) can heat up to 60°C, and last longer than Evacuated Tube Collectors
  • Evacuated Tube Collectors (ETC) can heat up to 70°C, but the evacuated tubes are fragile and have shorter life. More than half the installed capacity in the world is of this type
  • Quality of water is a concern
    • Systems without heat exchanger are cheaper, and can be used where water quality is good
    • Heat exchanger is a must where water quality is poor, but cost is much higher
  • Solar water heating is a Rs.200 Crore market in India
  • Globally, China is the largest market followed by Europe, Japan, and India
    • India’s target is 22 million sq.meters of collectors by 2022; China’s target is 300 M by 2020
  • Prominent companies in this sector include Emmvee Solar Systems (India), Genersys Solar (UK), Nuetech Solar System (India), Phoenix Solar (Germany)

Medium Temperature Solar Thermal Applications


  • The primary driver for this solar solution is the very large number of industrial applications that require process heat in this temperature range
    • India alone is a 17 GWth market in this temperature range
    • Solar can potentially replace Rs.20,000 Crores that is currently being spent on fossil fuels
    • Solar is more expensive than wood or coal, but very cost-effective against diesel or LPG
  • Enhanced Evacuated Tube – Variation of ETC that achieves higher temperatures by passing the liquid through multiple tubes. This is currently in early stages of commercialisation
  • Compound Parabolic Concentrator (CPC) – Comprised of rotated parabolic sections; can heat to higher temperatures than Evacuated Tubes. This technology is in late R&D stage


  • Variability of solar power, requiring dual fuel controls
  • Maintaining sufficiently high temperature through flow engineering
  • Prevention of steam formation
  • For CPC – Commercialization
  • Prominent companies include Aspiration Energy (India), Edmund Optics (USA)
  • High Temperature Solar Thermal Applications

    This is the domain of the concentrated solar thermal, where high temperatures are reached by concentrating the sunlight many times from the original.


    Technologies in use include:

    • Parabolic Trough – Parabolic trough that concentrates light on a receiver filled with a working fluid. Temperatures range from 150-350°C
    • Linear Fresnel Reflectors – Long thin strips of mirrors focus sunlight onto an absorber. Features single-axis tracking. Temperatures can reach up to 750°C
    • Parabolic/Paraboloid Dish – Parabolic reflector (or mirrors in paraboloid form) with dual-axis tracking. Temperatures are in the range of 250-700°C


    • Incorporating into/with existing infrastructure and fuel
    • Weight reduction for mounting on prefabricated industrial sheds
    • Predominantly dairy and food applicants, many European installations as pilots/demos. Worldwide, only a few hundred installations currently exist.
    • Several Indian players are prominent players in this sector, including Taylormade Solar Solutions, Sharada Inventions, Megawatt Solutions, Clique Developments, and Thermax
    • International players include Industrial Solar (Germany), TrivelliEnergia (Italy), Solitem (Germany), and NEP Solar (Switzerland)

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