• CSIR - Central Salt & Marine Chemicals Research Institute
  • G20
Devices & Sensors

Title of Process/ Know-how/ Product/Design/Equipment

Decentralized solar thermal dryer for hygienic drying of food products

  • IPR
    IPR Status & Details:
  • IN 320446
Application/Uses/Problem being addressed

Solar dryer technology is simple and therefore easily adoptable by the household, community and food processing sector. Mixed mode type of solar dryers have been designed, fabricated and tested for drying of food products like papad, potato wafers, banana wafers, grapes, onion, garlic, ginger, red chilies, methi leaves, mushrooms etc. at CSIR-CSMCRI, Bhavnagar. The capacity of the dryers can be varied from 5-20 of kg of raw material per batch, however it depends on the nature of the food to be dried. The drying of various food products can be achieved in about half the time duration taken for open sun drying. Based on the small-scale design, a 0.6 T/batch dryer was installed at Sagar Island for drying of freshly caught fish.

Benefits of solar thermal dryer include:

  • Since the food is enclosed it is therefore protected from dust, insects, birds, flies and wandering animals.
  • Higher temperature reduces the risk of spoilage due to microorganisms.
  • The unit is waterproof and thus the product need not be moved when it rains or at night
  • The unit can be constructed form the locally available materials.
  • Sometimes in open sun drying color of the product changes because of direct sun light exposure. In a solar dryer the color of the product is retained as the product is not directly exposed to sunlight.
  • Less risk of spoilage because of the speed of drying, as because, slow drying has tendency to result in fermentation and spoilage
  • The quality of the product is better in terms of nutrients and hygiene.
    • Salient Technical Features including Competing Features/ Impact

    The innovative features of CSIR-CSMCRI solar thermal dryer are:

  • Operation entirely on solar thermal energy and solar photovoltaic (PV) power and hence suitable for off-grid and remote locations.
  • Solar PV powered dehumidifier installed inside the unit maintains desired temperature and relative humidity (RH) at night, in order to prevent reabsorption of moisture and finish drying of a batch in shorter time
  • 85-90 % solar UV cut-off, so that better colour retention is obtained, and better price fetched.
  • Solar PV operated heaters for inclement weather conditions.
  • Renewable energy-based technology.
    • TRL Level & Scale of Development:
    TRL 5
    Business scope & opportunity (in terms of scale, cost, market etc.):

    Predominantly societal. Proliferation anticipated through licensee.

    Environmental Considerations:

    Clean and green technology

    Status of Licensing:
    Not yet licensed
    Status of Commercialization:
    Not yet commercialized

    Installed 0.6 T/batch capacity in a location and at 5 -10 kg/batch capacity as demonstration units in two locations.

    Major Raw Materials Needed

    Hardware material like plastic sheet, metallic sheets, anodized aluminum sheet, rods, pipes, PV panels, battery inverters etc.

    Major Plant Equipment and Machinery Required

    Modular units are needed to be fabricated in workshop

    Techno-Economics

    As a demonstration project, 0.6T/batch solar thermal dryer (0.3 Tx2) was installed at Sagar Island in for coastal fishing community which enhanced their profit by ca. 2.7 times.

    Technology Package

    Available on request