1. BANANA TEAM DESIGN
Sun Dryer Project
Product: Outdoor Food Sun Dryer.
Paul Escande & Tiphaine Luciani & Fadi Halloumi & Guilhem Desq
1st April, 2011.
Supervisor Teacher:
Anne Mason

2.
Contents Table
I. The Needs: ................................................................................................................................... 3
II. Research: ..................................................................................................................................... 3
III. Project Planning: ..................................................................................................................... 5
IV. Properties/Features: ............................................................................................................... 6
V. Design Ideas: ............................................................................................................................... 7
VI. Chosen Idea: ............................................................................................................................ 7
VII. Development stage: ................................................................................................................ 8
2
VIII. Industrial process: ................................................................................................................. 10
References ............................................................................................................................................. 11
<elle veut une table de matiére du style I puis I.1 I.2 toujours mentionné l’hérarchie>

3.
Introduction
I. The Needs:
In Africa, people need to preserve food in order to eat during periods of shortage. A used method
is to dry food using sun and wind, but it has many drawbacks. It takes a long time. There are insect
infestations, contaminations by dirt, birds, and rats. The food can be damaged by rains.
II. Research:
Famine is still a too well known phenomenon in Africa, as it could be seen on this diagram:
3
Figure 1: Production growth evolution in the last four decade.
Nearly 35 million Africans are currently facing famine, and most of them won’t be able to survive it.
The touched regions are mostly southern and the corn of Africa.
Figure 2: Famine touched regions.

4.
According to UN agencies, African governments put the number at risk in the Horn of Africa at about
15 million, over 14 million in southern Africa and hundreds of thousands in the Sahel region of West
Africa.
They are not able to buy enough food and so they will probably have to deal with hunger their whole
life…
Hundreds of millions of people are still underfed, although there is more than enough food to go
round.
The principal cause of famine in Africa is climatic conditions.
4
The immediate cause is drought, which has ruined harvests and left people and livestock without
food and water.
This drought is not the only reason why Africa suffers regularly from famine and widespread
malnutrition.
Most of African countries are not self‐sufficient in food; moreover, those bad climatic conditions
made prices increasing, making life harder than it already is...
Other causes exist such as hurricanes, earthquake, flood or Predators' invasion (insects especially).
Bad natural conditions of the country are obviously a handicap for the agriculture and breeding.
Some regions, as tropical regions for example, are exposed to a very variable climate which is
favouring the increase of parasites and the decline of national production.
Those conditions influence on food preservation which happen to be a big issue in Africa.
What is happening is that food can't be preserved because of germs and climate sometimes.
This is what our subject is going to be focus on: food preservation.
Before studying the different conservation methods, we are going to get focus on the proliferation of
germs. What does it need to develop itself? Germs are the principal reason of the food degradation.
To develop, germs need:
‐ Food (carbon, vitamins, salts, minerals …)
‐ Water
‐ Warm
‐ Oxygen
All of the conservation methods aim to eliminate the access to one of those elements. Once it is
done, the access should be restricted, not to let the process starting again...
Different techniques could be used to preserve food; it depends on the foodstuff and capabilities.
The current methods are about drying, freezing, pasteurization or vacuum… One of the oldest

5.
processes is drying, which is reducing the action of water whereas vacuum is reducing the quantity of
air and so reducing the action of oxygen.
What is an advantage with drying food is that dehydration reduces weight and volume which is a
certain economy for storage. What could be a problem is the taste of products which can be
modified. The rehydration could be difficult sometimes, and nutritive value could be reduced. To set
up, rodents, insects and bad conditions aggravates the famine phenomenon; this is why a drying food
is very efficient. Being very piratical to install, it could also be often used by the population.
III. Project Planning:
5

6.
Design Brief
On this Project, the team is asked to design a product which enables to dry the food faster and
safer, and then stores it.
Design Specification
6
IV. Properties/Features:
The design must:
– Dry the food faster (the temperature has to be higher than the if you were only using the heat of
the sun)
– Protect the food from rains, birds and rats.
– Store and preserve the food after drying it.
– Not burn the food.
– Not burn users: the dryer has to be isolated.
– Be cheap.
– Be movable and large enough to be used by a family.
– Fit in with the African architecture.
– Use materials you can find there.
– Be unreachable by children.

7.
V. Design Ideas:
7
Figure 3: Third design draft.
VI. Chosen Idea:
<ici l’idée qu’on a choisi et pourquoi on la choisie >

8.
Development
VII. Development stage:
Main structure:
For the main structure, two materials are interesting:
1 – The wood
8 Advantages:
‐It is easy to work with wood.
‐Wood is cheap
‐It is a light material.
‐Respects the environment
Inconvenient:
The wood may be treated with chemical product
2 – The cob
Advantages:
The cob is made with clay, sand, straw, water, and earth, and all of
these elements can be found easily in Africa.
Cob offer significant advantages due to his greater thermal mass
compared with wood.
Inconvenient:
‐It would be difficult to fix glasses on it.
‐The dryer would be very heavy and it would not be movable.
Base:
The base is made of wood cylinders with a radius of 5 cm.
Glasses:
The dryer does not need to be well‐isolated. Indeed, the air is always removed and replaced.
So the dryer does not have to be made with a material with high thermal properties.

9.
In order to respect our design specification and for its easy use, the wood will be used for the
main structure.
For the glasses we have two solutions, glass or Plexiglas. The working temperature of
Plexiglas is between ‐40°C and 70°C so it does not fit with the wanted temperature. We will
use glass.
Protection grid:
Mosquito net mesh size: between 0.6 and 1.2 mm. But this mesh size implicit that the net is
weak. Birds and rats can easily break it. A protection grid will be placed in front of the net
9 with mesh size between 2 and 3cm.
Racks:
The racks are made of a frame in wood. On each frame a net is fixed. The net have to be
enough solid to support the food's weight, but it must let pass enough air.
Size:
Dryer size:
The dryer has to be movable and be large enough to be used by a family, so we choose these
dimensions.
Height: 1.50 m
Length: 1.20 m
Width: 50 cm
Rack size:
The rack must be easy carried.
Height: 8.4 cm
Width: 50 cm
Length: 1.20 m
Air heater size:
The air heater has to receive enough sunbeams.
Height: 20 cm
Width: 60 cm
Length: 1.20 m

10.
Here is a quick look of diverse parts:
10
Figure 4: CAD Design Model (Solidworks).
VIII. Industrial process:
1 – Prepare the wood boards.
2 – Assemble the boards with wood glue and crews in order to build the main parts
separately:
‐ the base
‐ the food container
‐ the air heater
‐ the door
3 – Paint in black the bottom of the air heater.
4 – Fix the grids on the air eater and on the food container.
5 – Fix the glasses on the air eater and on the food container.
6 – Assemble all the parts together.
7 – Prepare the rack:
o Prepare each frame
o Set a net on each frame
8 – Dry your food!

11.
References
Dehydration of Food
http://www.uga.edu/nchfp/publications/uga/uga_dry_fruit.pdf
http://www.canningpantry.com/dehydration‐of‐food.html
http://www.barlowscientific.com/technotes/home/dry_food.html#pretreat
http://www.preservefood.com/drying.html
11 Water Pasteurization
http://solarcooking.wikia.com/wiki/Water_pasteurization
http://www.climbing‐high.com/how‐to‐purify‐water.html
http://en.wikipedia.org/wiki/Water_Pasteurization_Indicator
http://solarcooking.org/pasteurization/default.html
Starvation
http://news.bbc.co.uk/hi/english/static/in_depth/world/2002/disposable_planet/food/
http://news.bbc.co.uk/2/hi/africa/2449527.stm
http://www.wfp.org/
http://en.wikipedia.org/wiki/Famine
Materials
http://en.wikipedia.org/wiki/Melting_point
http://en.wikipedia.org/wiki/Cob_%28material%29
Figures Table
Figure 1: Production growth evolution in the last four decade. ............................................................. 3
Figure 2: Famine touched regions. .......................................................................................................... 3
Figure 3: Third design draft. .................................................................................................................... 7
Figure 4: CAD Design Model (Solidworks). ............................................................................................ 10