1. Solar Food Drying
Gordon Hirst: Chief Engineer LIRE/SLB
Sunlabob Renewable Energy, Ltd
Lao PDR
29 November, 2012
Solar Food Drying

2. What is Sunlabob?
Laos-based social enterprise
that specializes in renewable energy & clean water
projects in developing regions of the world.
Solutions & Technologies:
Solar PV
Mini-hydro power
Water purification
Energy efficiency
Operating in:
Southeast Asia
Africa
India
Pacific Islands

3. Solar Food Drying
• Sunlabob Mission
 Profit-driven, socially-minded business approach
 Focus on economic, social and environmental sustainability
 Deliver clean energy and water to rural, off-grid populations

4. Solar Food Drying
• Lauching of Sunlabob
 2001: The first commercial
company working in the field of
renewable energy in the Lao PDR
 Aim: Provide renewable energy
solutions to rural areas not yet
connected to the national grid.
Founders: Andy Schroeter and
Saleumphone Vongsakhampui

5. Solar Food Drying
• Benefits of Solar Food Drying
Clean energy
Reduction of energy costs
Clean drying (no smoke)
Reduction in GHG’s (Carbon Credits ?)
Hygienic
• Disadvantages of Solar Food Drying
Not controllable and production is dependant on natural
Phenomenon

6. Solar Food Drying
Conversion of solar irradiation into usable
energy
•Solar power PV cells (Not suitable for solar drying)
•Solar Thermal (liquid)
•Solar Air

7. Solar Food Drying
• Solar PV cells

8. Solar Food Drying
• Principles of solar thermal (water) drying

9. Solar Food Drying
• Principles of solar air drying

10. Solar Food Drying
• Principles of solar air drying

11. Solar Food Drying
Solar air vs Solar thermal
• Solar air
 Simpler and cheaper
 Much less moving parts
 Does not require a thermal transfer stage
 Easier to expand system
• Solar thermal
 Higher irradiation absorption
 Heat storage capacity is greater

12. Solar Food Drying
• Solar survey theory

13. Solar Food Drying
• Heat energy required

14. Solar Food Drying
• Solar survey
Heat energy (solar irradiation) x ɳ (inefficiency : heat loss)≥ Heat
energy required
Energy input profile required by food crop = heat generation profile.

15. Solar Food Drying
Solar survey
Basic heat energy equation
Q = mCpΔt
Where:
m = mass flow rate
Cp = Specific heat capacity of air = 1.005 Kj/Kg K
Δt = Temperature differential
Volumetric flow rate
Vq = m/ρ
Where:
Ρ = density of air: dependant on altitude

16. Solar Food Drying
• System design
1. Solar collectors design
2. Integration with building structure (wind and static loading)
3. Air collection and transportation (Ductwork)
4. Blower
5. Back Up system
6. Filtration
7. Control
8. Dryers

17. Solar Food Drying
• System design

18. Solar Food Drying
• Solar collectors

19. Solar Food Drying
• Solar collectors

20. Solar Food Drying
• Blower

21. Solar Food Drying
• Blower duty

22. Solar Food Drying
• Back up system

23. Solar Food Drying
• Filter

24. Solar Food Drying
• Control

25. Solar Food Drying
• Control

26. Solar Food Drying
• Static bed driers

27. Solar Food Drying
• Drum Dryers

28. Solar Food Drying
• Solar drying examples

29. Solar Food Drying
• Solar drying examples

30. Solar Food Drying
• Carbon Credits
Use of renewable energy is a fuel switch from fossil fuel and is
eligible for carbon credits.
CDM Methodology
AMS- I.E ver 5
Switch from non-renewable biomass for thermal
applications by the user

31. Sunlabob Contact
Thank You
Sunlabob Renewable Energy, Ltd
PO Box 9077, Vientiane, Lao PDR
Tel: (+856-21) 313874 - Fax: (+856-21) 314045
contact@sunlabob.com
www.sunlabob.com