design

2. ASSOSA UNIVERSITY

3.  INTRODUCTION
 STATEMENT OF PROBLEM
 OBJECTIVES
 SIGNIFICANCE OF
PROJECT
 SCOPE OF PROJECT
 LIMITATION OF PROJECT
 LITRATURE RIVIEW
 METHODOLOGY
 MATERIAL SELECTION
 DESIGN ANALYSIS
 RESULT AND DISCUSSION
 CONCLUSION AND
RECCOMENDATION

4.  Solar energy was radiant light and heat from the sun hardness using
arange of ever envolving technologies such as a solar heating, solar
thermal energy, solar architechture and artificial photosynthesis.
 The main uses of solar energy was used for water heating, heating,
cooling, ventilation, cooking, water treatment, electricity power,
transport,drying and agriculture and horticulture
 The solar dryer is a methods of using solar energy that come from the sun
by absorbing and reflecting to drying materials and the materials lose their
mosture and become dried and solar dryer is used in agriculture for food
and crop drying for industrial drying process, dryer can be proved to be
most useful device from energy conservation point of view

6.  two types of solar dryers those are
 Direct solar dryer is expose the substance to be
dehydrated to direct sun light, example food and clothing
was dried in the sun by using lines. In this system the
solar drying is assisted by the movement of the air that
removes the more saturated air away from the items
being dried.
 Indirect solar dryers the black surface heats incoming air
rather than directly heating the substances to be dried.
This heated air is then passed over the substance and
exits upward, released from the substance within it

7.  Among the application of solar thermal energy, solar drying was
an important application in agricultural process.
 In Ethiopian the usual practice was an open air drying system for
drying of fruits, vegetables and crops.
 This method of drying has many disadvantages like
 spoilage of product due to
 Adverse climate condition like rain, wind, moist and dust
 Loss of materials due to birds and animals, detritions of the
material by decomposition insects and fungus growth.
 As a result the quality of the dried products can be degraded.

8. GENERAL OBJECTIVE
 The overall objective of this work is to design a cost
effective solar crop dryer.
SPECIFIC OBJECTIVES
The specific objectives of this project are:
 To determine the amount of energy requirement to reduce
the moisture content of fruits and vegetables.

9.  To design a flat plate air heater, these include
determination of the solar energy absorbed by the flat
plate air collector, energy loss from the collector, and
the area of the collector.
 To design of the drying chamber.

10.  They consume and used the food and vegetables for long
period of time.
 They protect their food as well as vegetables from bacteria’s,
insects and animals.
 It saves their time that waste on protecting food from animals
and insects.

11.  There is no enough raw materials to change in to
products
 The work shop is not well organized

12.  The scope of the project is limited on the design of
solar crop drying system to dry crops, fruits and
vegetables

13. 1) low cost solar dryer technologies to bhutanase organic
produce An effort was made by SAMDRUP JONGKHAR IN
2012.
It uses vegetables and fruits drying methods,it explained
the help extend shelf life, access new market opportunities
and fetch good prices. The aim of project is to contribute to
equitable and balanced socio-economic development and
poverty reduction putting in place of frame work
So, It recommended that use glass in terms of plastics

15. 2) DESIGN AND MANUFACTURING OF SOLAR DRYER
An effort was made by MECHANICAL ENGINEERING
STUDENT OF CALIFORNIA UNIVERSITY
 The aim is to solve the problems of effective food
preservation as lack of appropirate presevation and
storage system caused cosiderable losses, thus reducing
the food supply significantly, the main component they
used are flat solar collector, drying chamber,insulation
panel(main body) ventilation system.

16.  use simple and low cost materials that are maintained in
short periods of time.

17. 3) CONCENTRARED SOLAR DRYING OF MANGO AND TOMATO
An effort was made by DIANE M.BARRETT,UNIVERSITY OF
CALIFORNIA DAVIS
 This project is design’s and tests a batch concentrated solar
power(csp) dryer for mangoes and tomatoes in simulated cloud
environments. Concentrated solar power will be evaluated
interms of drying efficiency cost and product quality

18.  modify the drying machine for multi-purpose function

19.  Our project is differing from above in giving multi porpose
function as we went. We can use glass interms of plastics, we
can reduces maintenance cost by selecting materials whch
have high strength and high duration and easily gotten from
our surroundings.

20.  Both Primary and secondary data collection systems will be
applied.
 Necessary Solar data were collected for the selected site
from Ethiopia National Metrological Service Agency
(NMSA) Assosa branch and NASA.
 Data concerning Relative humidity were collected from
NASA.
 From different available books, journals, articles and Internet

22.  DECLINATION ANGLE
 = 20.340
=20.340
ANGLE OF INCIDENCE
=20.340

23.  ZENITH ANGLE= 0
 EXTRATERRESTRIAL INTENSITY=
Iext = 1332.4W/m2
 INTEGRATED DAILY EXTRATERRESTRIAL RADIATION
Ho =38.1*10^6 J/m2

24.  DAILY RADIATION ON HORIZONTAL SURFACE =
H=24.77*10^6
 HOURLY TOTAL RADIATION=
I=928.875W/m2

25.  DIFFUSED RADIATION:
Id=232.2w/m2
BEAM RADIATION =Ib = 696.656W/m2
THE TOTAL RADIATION ON THE INCLINED COLLECTOR
IT = 888.33W/M2
g

= 0.261

26. CALCULATION OF THE ABSORBED SOLAR RADIATION
1)BEAM REFLECTED TRANSMITTANCE
=0.804
GROUND REFLECTED TRANSMITTANCE
= 0.261
DIFFUSED TRANSMITTANCE
= 0.730

27.  The total solar energy absorbed is given as
S = 638.416W/m2
 DESIGN OF SOLAR COLLECTOR
 Calculation of overall heat transfer coefficient, UL
= 99.6kW/m2K
 Efficiency of collector is= 14.77%

28.  First we select the temperature of 3 years, from those temperatures we can
select the months which have smooth temperature variation that is march
month, again from march we can select maximum continuous temperature
variation that is day 22, after that we can calculate the solar intensity which
means the solar ( sun)radiation that exist before reaching the earth. Under this
we can calculate declination angle which means the angle of solar radiation
used to reach the earth that is 20.34 degree after that we can calculate the
angle of incidence that means the solar radiation moving on straight line with
declination angle to reach surface which is 20.34 degree, zenith angle which
mean the sky angle which make directly overhead got 0 degree,

29.  extraterrestrial intensity means solar radiation outside of the earth atmosphere which
gotten 1333.4w/m2, radiation on horizontal surface means solar radiation that has been
reach on the horizontal surface under this, 232.2w/m2 was diffused.
 696.659w/m2 was the radiation that reaches on beam surface. In the second we can find
the total radiation that is reach on the collector, solar energy that absorbed by collector
under this we can gain 0.804 is reflected by beam, 0.261 is reflected by ground and
0.730 is diffused,


30.  so we can calculate the overall solar absorbed energy by collectors. At
the end we can calculate the overall heat losses that occur in the solar
collector which is 99.6w2/m2k. After that we can get the efficiency of
the collector that means amount of solar energy used to release the
moisture and dries the crops and crops which is 14.77%.

31.  Generally solar crop dryer is the most cost effective energy and it must be adopted and practiced in
Ethiopia. As the system uses the most renewable and sustainable energy of the sun no hurt of the
pollutants execration which are the hazards of the global warming. The solar crop dryer is give
multipurpose function that must be used as we wonted. In our project we have design solar crop
dryer and their components. There are many types of solar collectors, but the most common type is
flat plate collector with black paints and which is used to reflect the solar energy reached on it. The
collector material used is cast iron which has high conductivity with relatively low cost, strength to
weight ratio, ease of fabrication. Most of the time more amount of solar radiation strikes a south
facing, so the panel is faced (installed) to south and tilted to about 13 degrees in accordance to the
latitude of the place. From the experiment solar crop dryer is more efficient and used for long period
of time and the operation is very simple and every person can operate it.

32.  The recommendation is putted as below
 Change the design into production or manufacturing.
 To increase the efficiency of the collector use the material
that has more conductivity.
 Use simple and easiest material that has gain from your
surroundings.


33. Air
inlet
Air outlet

34. THANK YOU
FOR YOUR
ATTENTION!!!