Multi commodity solar tunnel Dryer

Multi commodity solar tunnel Dryer (MCSTD)

The Philippine commonly practices sundrying techniques in drying fish products. However, the process is a largely dependent on the weather and is very difficult during the rainy season.

Moreover, the traditional method usually yields products with high microbial load. The exposure to wind and weather is a relatively slow process and results to a bigger losses through spoilage, lack of uniformity in the final product and development of undesirable flavor.

The studying practice of small-scale producers diminishes the quality of the commodities being dried. The practice allows dust, flies and microorganisms to contaminate the products. Aside from its health hazards, the poor quality dried products fail quality standards and are unacceptable for export. Worse, many small-scale processors cannot afford the operation coast of commercial mechanical dryers.

To help solve this problem, the MultiCommodity Solar Tunnel Dryers (MCSD) technology was adapted by PHilMech as a viable alternative to sundrying and use of commercial mechanical dryers. This dryer is a modified version of the solar tunnel dryer developed by the researchers of the Hohenheim University in Germany.


Cheaper in investment and operation cost than other available commercial mechanical dryers.

Dries commodities simultaneously, efficiently and hygienically

Preserves the quality of dried products longer because of lesser microbial contamination

Allows ready supply of processed food products even during lean  months

Uses locally available materials to suit the needs of the farmers and fisherfolks engaged in processing

Easy to install/dismantle and maintain

Convenient to use

Gender friendly, can be used by women


Return of Investment (ROI)

Financial analysis revealed that if MCSTD is acquired through facility loan payable in 5 years at 14% annual interest rate, the enterprise will be profitable. The investment can be recovered within 4.15 years. An investment spread of 3.10% is realized when the discount rate (14%) is deducted from the calculated IRR. The net present value is still positive and the benefit cost ratio is slightly above the cut-off rate. The return of investment is 21.60%

The table below shows the financial analysis of using MCSTD acquired through facility loan.

FINACILA INDICATORS MCSTD acquired through facility loan
Payback period 4.15 years
Internal rate of return 15.92%
Net present value 30,300.95
Benefit cost ratio 1.06
Return of Investment 21.60%


Drying components

The PHilMech’s MCSTD has three major componenets: the heat collector, drying chamber and fan/blower.

The heat collector and drying chamber are covered with UV-stabilized polyethylene plastic sheets, mounted in inverted “V” metal frames. The floor is made of bended metal sheets with PEfoam insolation . The trays containing the products are placed on top of the ribbed drying flor.

A series of axial fan with electric motor forces air into the heat collector which increases the drying air temperature to 45 degrees Celsius to 60 degrees Celsius.


Parts of the MCSTD

A drying bed where the commodities are spread

A blower at one end where a burner may be installed for supplemental heating on rainy days.

Top plastic cover to trap the sun’s heat and protect the commodities from sudden rainfall, dust and insect.



The PhilMech’s MCSTD is fabricated using locally available construction materials. The modular design allows easy transport and installation in the processing areas.

Commodities: Banana, cassava, danggit, dilis camias, mushroom, tomato, espada, etc.

Construction materials:

Heat collector and drying bed – bended metal sheet, G.I  pipe and plastic sheet

Blower – 1.0 -1.25 m/sec . 22- v, single phase


Heat collector=L-7.3 m, w- 2 m

Drying bed = L-9.8 m , W 2 m

Axial fan = 88 watts , 220 v

Investment cost = 180,000 to 230 , 000


Drying performance

Aside from providing better quality dried products, the drying performance of MCSTD is significantly better than the traditional sundrying methods in terms of shorter drying time

Product dried Load (kg) MCSTD (days) Sundrying (days)
Banana 100 1 1-2
Cassava 200 1.5 2
Danggit 50 1 2
Dilis 50 1 1-1.5
Dried camias 100 1 2
Dried mushroom 60 1 2
Dried tomato 400 3-4 7
Espada 40 ½ 1-1.5
Mango 160 2.5 3-4
Squid 40 ½ 1-1.5
Shrimp 60 ½ 1
Tamarind sweet 300 3-4 7
Tomato sweats 600 3-4 7
Young tilapia 60 1-1.5 3-4


Source: PhilMech pamphlet


2 thoughts on “Multi commodity solar tunnel Dryer”

  1. Hi Ma’am/Sir, Good Day!

    I would like to inquire regarding with your Multi-Commodity Solar Tunnel Dryer (MCSTD)

    if it is available?

    Thank you so much and looking forward to hear from you.

    Regards ,
    Mary Grace Suganob

  2. What are the specs of the plastic cover placed in the MCSTD to protect the samples to be dried. Thank
    you ! The thickness

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