DESIGN AND DEVELOPMENT OF SOLAR DRYER FOR FRUIT CHIPS

Full text

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DESIGN AND DEVELOPMENT OF SOLAR DRYER
FOR FRUIT CHIPS
A PROJECT REPORT
Submitted by
JAYESH.R.LAKHANI (090210119025),
VISHAL.T.PATEL (090210119003),
TUSHAR.G.TADHA (090210119050),
MAYABHAI.B.KAMALIYA (090210119082)
In fulfilment for the award of the degree
Of
BACHELOR OF ENGINEERING
In
MECHANICAL DEPARTMENT
Government Engineering College, Bhavnagar.
Gujarat Technological University, Ahmedabad.
May, 2013
GOVERNMENT ENGINEERING COLLEGE, BHAVNAGAR.
MECHANICAL ENGINEERING DEPARTMENT
MAY 2013

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CERTIFICATE
This is to certify that the project entitled “DESIGN AND
DEVELOPMENT OF SOLAR DRYER FOR FRUIT CHIPS” has
been carried out by JAYESH.R.LAKHANI, VISHAL.T.PATEL,
TUSHAR.G.TADHA, MAYABHAI.B.KAMALIYA under my
guidance in fulfilment of the degree of Bachelor of Engineering in
Mechanical Engineering Department (8th semester) of Gujarat
Technological University, Ahmedabad during the year 2012-13.
Guide: Prof. J.B.Valaki
Head of the Department

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DEDICATION
To my friends for their love and moral
support during the course of project work and
finally to encouragement towards the successful
completion of this work.

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ACKNOWLEDGMENT
This dissertation would not have been possible without the guidance and
the help of several individuals, who in one way or the other have
contributed and extended their valuable assistance in the preparation and
completion of this project.
First and foremost, we would like to take this opportunity to thank our
project guide Prof. J.B.Valaki, for his patience, guidance, motivation,
and utmost support towards completion of the project. He has guided us
towards obtaining the solution consistently so that we are able to
complete our project on time with the tight schedule. He is a
tremendously good guide, who exhibits his extensive cares, experiences,
disciplines and guidance towards his project students.
We would also like to thank other faculty members, classmates, friends
who have contributed in our project and also for their moral support and
encouragement.
Last but not least, we would like to show our deepest thankfulness to our
family and loved ones, who have shown us their concern and full
support.

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TABLE OF CONTENTS
TITLE PAGE………………………………………………………….. 1
CERTIFICATE………………………………………………………...2
DEDICATION……………………………………………………….....3
ACKNOWLEDGMENT………………………………………………4
TABLE OF CONTENT………………………………………………..5
LIST OF FIGURES .......................…………………………………...7
LIST OF TABLES…….…………………………………… ………....8
Chapter: 1 PROJECT IDENTIFICATION.........................................9
1.1 PROJECT IDENTIFICATION……………………………… 10
1.2 PROJECT STATEMENT………………………………...…. 11
1.3 CONCEPT GENERATION………………………………..…. 11
1.4 IMPORTANCE OF SOLAR FRUIT DRYER………………... 11
1.5 HYPOTHETICAL WORKING OF SOLAR FRUIT DRYER.. 13
1.6 CONCEPTUAL DRAWING OF SOLAR FRUIT DRYER…... 14
1.7 OBJECTIVE OF SOLAR FRUIT DRYER……………………. 15
1.8 APPLICATION OF SOLAR FRUIT DRYER………………… 15
Chapter:2 LITERATURE REVIEW……………...…………...........16
Chapter : 3 METHODOLOGY AND IMPLIMENTATION……..21
3.1 MATERIALS AND TOOLS OF SOLAR FRUIT DRYER…….. 22
3.2 OVERVIEW OF SOLAR DRYER ……………………….............23
3.2.1 CONSTRUCTION OF SOLAR FRUIT DRYER………...23
3.2.2 COMPONENTS OF SOLAR FRUIT DRYER…………….23

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3.2.3 ORIENTATION OF SOLAR FRUIT DRYER…………….24
3.3 OPERATION OF SOLAR FRUIT DRYER……………………24
3.4 DESIGN………………………………….......................... …….. 25
3.5 DESIGNCONSIDERATION……………………………………... 27
CHAPTER : 4 CALCULATION.......................................................28
CHAPTER : 5 FABRICATION AND ASSEMBLING…………...32
CHAPTER : 6 PROJECT COST CALCULATION…………....…38
CHAPTER : 7 TESTING……………………………………………40
CHAPTER : 8 CONCLUSION……………………………………..42
CHAPTER : 9 REFRENCES……………………………………….44

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LIST OF FIGURES
FIGURE NO.
NAME
PAGE NO.
1
Detail drawing of solar
fruit dryer
12
2
Box Dryer
15
3
Schematic diagram
23
4
Assembly Drawing
24
5
6
7
8
9
Solid model
Glass wool insulation
in heating chamber
Heating chamber
Tray arrangement
Final project photo
24
34
35
36
37

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LIST OF TABLES
TABLE NO.
NAME
PAGE NO.
1
Different solar
irradiance
9
2
Information about
fruits
10
3
Classification of solar
dryer
11
4
5
Bill of material
Test Reading
20
41

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CHAPTER 1
PROJECT
IDENTIFICATION

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CHAPTER 1
1.1 PROJECT IDENTIFICATION
Agricultural and other products have been dried by the sun and wind in
the open air for thousands of years. The purpose is either to preserve
them for later use, as is the case with fruit; or as an integral part of the
production process, as with timber, tobacco and laundering. In
industrialised regions and sectors, open air-drying has now been largely
replaced by mechanised dryers, with boilers to heat incoming air, and
fans to force it through at a high rate. Mechanised drying is faster than
open-air drying, uses much less land and usually gives a better quality
product. But the equipment is expensive and requires substantial
quantities of fuel or electricity to operate.
Solar fruit dryer are simple devices to heat fruit chips by utilizing solar
energy and employed in many applications requiring low to moderate
temperature below 80oDrying processes play an important role in the
preservation of agricultural products.
'Solar drying' in the context of this technical brief, refers to methods of
using the sun's energy for drying, but excludes open air 'sun drying'. The
justification for solar dryers is that they may be more effective than sun
drying, but have lower operating costs than mechanised dryers. A
number of designs are proven technically and while none are yet in
widespread use, there is still optimism about their potential.
The solar dryer can be seen as one of the solutions to the world’s food
and energy crises. With drying, most agricultural produce can be
preserved and this can be achieved more efficiently through the use of
solar dryers.
Thus, the solar dryer is one of the many ways of making use of solar
energy efficiently in meeting man’s demand for energy and food and
fruit supply, total system cost is a most important Consideration in
designing a solar dryer for agricultural uses. No matter how well a solar
system operates, it will not gain widespread use unless it presents an
economically feasible alternative to other available energy sources.

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1.2 PROJECT STATEMENT
 To design and develop a solar fruit dryer which dries various fruit chips
with application of only a small amount of effort and use of Solar
energy.
1.3 CONCEPT GENERATION
The idea of using solar energy to produce high temperature dates back to
ancient times. The solar radiation has been used by man since the
beginning of time for heating his domicile, for agricultural purposes and
for personal comfort. Reports abound in literature on the 18th century
works of Archimedes on concentrating the sun’s rays with flat mirrors;
Modern research on the use of solar energy started during the 20th
century. Developments include the invention of a solar boiler, small
powered steam engines and solar battery, but it is difficult to market
them in competition with engines running on inexpensive gasoline.
During the mid-1970’s shortages of oil and natural gas, increase in the
cost of fossil fuels and the depletion of other resources stimulated efforts
in the United States to develop solar energy into a practical power
source. Thus, interest was rekindled in the harnessing of solar energy for
heating and cooling, the generation of electricity and other purposes
(Leon, et al., 2002).
Clear,blue
sky
Scattered
clouds
Overcast
sky
Solar
irradiance[w/m2]
1300-
1400
800-
1000
300-400
Diffuse
fraction[%]
10-20
20-80
80-100
TABLE 1 – DIFFERENT SOLAR IRRADIANCE
1.4 IMPORTANCE OF SOLAR DRIED FRUITS
For centuries, people of various nations have been preserving fruits,
other crops, meat and fish by drying. Drying is also beneficial for hay,
copra, tea and other income producing non-food crops. With solar energy
being available everywhere, the availability of all these farm produce can
be greatly increased. It is worth noting that until around the end of the

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18th century when canning was developed, drying was virtually the only
method of food preservation. (Bean et all, 2002).
Ikejiofor (1985) stated that the energy input for drying is less than what
is needed to freeze or can, and the storage space is minimal compared
with that needed for canning jars and freezer containers. It was further
stated that the nutritional value of food is only minimally affected by
drying.
Also, food scientists have found that by reducing the moisture content of
food to 10 to20%, bacteria, yeast, mold and enzymes are all prevented
from spoiling it (Gallali, et al., 2000). Microorganisms are effectively
killed when the internal temperature of food reaches 145°F. The flavour
and most of the nutritional value of dried food is preserved and
concentrated. Dried foods do not require any special storage equipment
and are easy to transport. Dehydration of vegetables and other food crop
by traditional methods of open-air sun drying is not satisfactory, because
the products deteriorate rapidly, studies showed that food items dried in a
solar dryer were superior to those which are sun dried when evaluated in
terms of taste, colour and mould counts.
Solar dried fruits are quality products that can be stored for extended
periods, easily transported at less cost while still providing excellent
nutritive value. This project work therefore presents the design and
construction of a domestic solar dryer.
NAME
DRYING
TIME
DRYING
TEMPERATUR
E
(°C)
MASS
FLOWRATE
OF AIR
(Kg/s)
THICKNESS
OF CHIPS
(mm)
BANANA
4 h 12 min
70-75
0.0252
6
APPLE
3h 30 min
65-70
0.0252
4
CHICKOO
3 h 52 min
70-75
0.0252
5
TABLE 2 – INFORMATION ABOUT FRUITS

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1.5 CLASSIFICATION OF SOLAR FRUIT DRYER
To classify the various types of solar dryer, it is necessary to simplify the
complex construction and various modes of operation to the basic
principles. Solar dryer can be classifying based on following criteria:
 Mode of air movement
 Exposure to insulation
 Direction of air flow
 Arrangement of dryer
 Status of solar contribution
Solar dryer can classify primarily according to their heating modes and
the manner in which the solar heat is utilised. In broad terms, they can be
classifying into two major groups, namely:
1. Active solar-energy drying system
2. Passive solar-energy drying system
TABLE 3 – CLASSIFICATION OF SOLAR DRYER

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1.6 CONCEPTUAL DRAWING OF SOLAR FRUIT DRYER
FIGURE – 1

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1.7 OBJECTIVE OF SOLAR FRUIT DRYER
The objectives of this project are:
 To create 2D and 3D model of solar fruit dryer.
 To design and construct a solar dryer.
 To evaluate the solar dryer’s performance
 To protect the product against flies, pests, rain and dust.
 It is labour saving. The product can be left in the dryer overnight or
during rain.
 To achieve better quality of product in terms of nutrients, hygiene and
colour.
 To improve family nutrition because fruit and vegetables contain high
quantities of vitamins, minerals and fibre.
 To improve the bargaining position of farmers.
 To encourage people to establish their own gardens.
1.8 APPLICATION OF SOLAR FRUIT DRYER
 Agricultural crop drying.
 Food processing industries for dehydration of fruits and vegetables.
 Fish and meat drying.
 Dairy industries for production of milk powder.
 Seasoning of wood and timber.
 Textile industries for drying of textile materials, etc,

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CHAPTER 2
LITERATURE
REVIEW

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CHAPTER 2
2.1 LITERATURE REVIEW OF SOLAR DRYER
In many parts of the world there is a growing awareness that renewable
energy has an important role to play in extending technology to the
farmer in developing countries to increase their productivity (Waewsak,
et al., 2006). Solar thermal technology is a technology that is rapidly
gaining acceptance as an energy saving measure in agriculture
application. It is preferred to other alternative sources of energy such as
wind and shale, because it is abundant, inexhaustible, and non-polluting
(Akinola 1999; Akinola and Fapetu 2006; Akinola et al., 2006).
The application of dryers in developing countries can reduce post-harvest
losses and significantly contribute to the availability of fruit in these
countries. Estimations of these losses are generally cited to be of the
order of 40% but they can, under very adverse conditions, be nearly as
high as 80%. A significant percentage of these losses are related to
improper and/or untimely drying of fruit chips such as banana, mango.
apple, chickoo etc. (Bassey, 1989; Togrul and Pehlivan, 2004).
The simplest design for a solar dryer was developed by the Brace
Research Institute, Canada, (1975). It is essentially a hot box where
fruits, vegetables or other materials can be dehydrated on a small scale
(see Figure 2.1).
FIGURE 2- BOX DRYER

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The construction of such a dryer can take many forms. Nevertheless,
certain specifications were recommended. The experimental results at
Kanpur, India (Chantawanasri, 1978) for the drying of fruits and
vegetables showed that solar-drying saved considerable time compared.
With sun-drying in the open. Also, the product obtained from the solar
dryer was found to be superior in taste and odour to sun-dried produce
and was not contaminated by dust or infested by insects.
Bahnasawy and Shenana (2004) developed a mathematical model of
direct sun and solar drying of some fermented dairy products (kishk).
The main components of the equations describing the drying system
were solar radiation, heat convection, heat gained or lost from the dryer
bin wall and the latent heat of moisture evaporation. The model was able
to predict the drying temperatures at a wide range of relative humidity
values. It also has the capability to predict the moisture loss from the
product at wide ranges of relative humidity values, temperatures and air
velocities.
Soponronnarit (1995) reviewed the research and development work in
solar drying Conducted in Thailand during the past 15 years (since
1980s). He found that, in terms of techniques and economy, solar drying
for some crops such as paddy, multiple crops and fruit is feasible.
However, the method has not been widely accepted by farmers. Most of
the solar air heaters developed in Thailand has used modifications to the
building roofs. Both bare and glass-covered solar air heaters were
reported to be technically and economically feasible when compared to
electricity but have not been able to compete with fuel oil.
Pangavhen, et al. (2002) proposed a design, development and
performance testing of new convection solar dryer, the solar dryer is
capable of producing average temperature between 50 and 55°C, which
was optimal for dehydration of grapes as well as for most of the fruits
and vegetables. This system was capable of generating an adequate
natural flow of hot air to enhance the drying rate. The drying airflow rate
increases with ambient temperature by the thermal buoyancy in the
collector. The collector efficiencies ranged between 26% for mass flow
rate of 0.0126 kg/s of air and 65% for mass flow rate of 0.0246 kg/s. This
was sufficient for heating the drying air. The drying time of grapes was
reduced by 43% compared to the open sun drying.

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Ekechukwu and Norton (1999) presented a comprehensive review of the
various designs, details of construction and operational principles for a
variety of practical solar-energy drying
systems. The appropriateness of each design type for applications used
by rural farmers in
developing countries was discussed.
Sebaii, et al. (2002) reported a study of an indirect type natural
convection solar which Investigated experimentally and theoretically for
drying grapes, figs, onions, apples, tomatoes and green peas. The drying
constants for the selected crops were obtained from the experimental
results and were then correlated with the drying product temperature.
Linear correlation between drying constant and product temperature were
proposed for the selected crops. The empirical constants of Henderson’s
equation were obtained for all the materials from investigation, which are
not available in the literature. The proposed empirical correlation
suggested that it could well describe the drying kinetics of the selected
crops.
Gallali, et al. (2000) reported the result of an investigation of some dried
fruit and Vegetables based on chemical analysis (vitamin C, total
Reducing sugars, acidity, moisture, and ash content) and sensory
evaluation data (colour, flavour, andtexture). They compared products
dried by solar dryers and natural sun drying. The study indicated that
using solar dryers gives more advantages than natural sun drying,
especially in terms of drying time.
Karathanos and Belessiotis (1997) reported the sun and solar air drying
kinetics of some agricultural products, i.e. sultana grapes, currants, figs,
plums and apricots. The drying rates were found for both solar and
industrial drying operations. Air and product temperatures were
measured for the entire industrial drying process. It was shown that most
materials were dried in the falling rate period. Currants, plums, apricots
and jigs exhibited two drying rate periods, a first slowly decreasing
(almost constant) and a second fast decreasing (falling) drying rate
period. In addition, they indicated that the industrial drying operation
resulted in a product of superior quality compared to products dried by
solar dehydration.
Leon, et al. (2002) presented a review of existing evaluation methods
and the parameters generally considered for evaluation of solar fruit
dryers. These parameters can be classified as: (i) physical features of the

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dryers; (ii) thermal performance; (iii) quality of dried product; (iv) cost
of dryer and payback period.
A) Physical features of dryer:
 Type, size, and shape.
 Collector area and solar aperture.
 Drying capacity/loading density (kg/unit aperture area).
 Tray area and number of layers.
 Loading/unloading convenience.
 Loading/unloading time.
 Handling, cleaning, maintenance convenience and ease of construction.
B) Thermal performance:
 Drying time/drying rate up to 10% product moisture content (db.), (this
may, however, vary from product to product).
 Dryer/ drying efficiency until product moisture content reaches 10%
(db.).
 First day drying efficiency.
 Drying air temperature and relative humidity.
 Maximum drying temperature at no-load and with load.
 Duration of drying air temperature10°C above ambient.
 Airflow rate.
C) Quality of dried products:
 sensory quality (colour, flavour, taste, texture, aroma)
 nutritional attributes - quantified for easy comparison
 rehydration capacity - consistency in presentation
 uniformity of drying

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CHAPTER 3
METHODOLOGY AND
IMPLEMENTATION

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CHAPTER 3
3.1 MATERIALS AND TOOLS OF SOLAR FRUIT DRYER
3.1.1 The following materials were used for the construction of the
domestic passive solar
Fruit dryer.
 Wood - as the casing (housing) of the entire system; wood was
selected being a good insulator and relatively cheaper than metals.
 Glass - as the solar collector cover and the cover for the drying
chamber. It permits the solar radiation into the system but resists the
flow of heat energy out of the systems.
 Alluminium sheet of 27 gauge thickness and aluminium painted black
– for absorption of solar radiation.
 Wooden frames for constructing the trays.
 Nails and glue as fasteners and adhesives.
 Hinges and handle for the dryer’s door
 Paint (black).
3.1.2 BILL OF MATERIAL
SR NO.
COMPONENT
MATERIAL
DIMENSION(mm)
1
Solar Collector
Glass
1750×1000
2
Absorber Plate
Aluminium
1750×1000
3
Heating Chamber
Wood
1750×1000×150
4
Drying Chamber
Wood
1000×1000×600
5
Insulation
Glass wool
50
6
Tray
Aluminium
500×850
7
Roof
Wood
1000×600
TABLE 4 - BILL OF MATERIAL
3.1.3 the following tools are used in the construction of solar fruit dryer:
 Hand saw or skill saw, if available
 Hammer
 Tape measure
 Framing square or tri-square
 Wood rasp
 Screw driver
 Tin snips

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 Staple gun
 Keyhole saw
 Paint brush
 Chalking gun
 Scissors
 Pencils
 Soaking pan
3.2 OVERVIEW OF SOLAR DRYING
3.2.1 CONSTRUCTION OF SOLAR FRUIT DRYER
The materials used for the construction of the mixed-mode solar dryer
are cheap and easily obtainable in the local market. The solar dryer
consist of the solar collector (air heater), the drying cabinet and drying
trays.
3.2.2 SOLAR FRUIT DRYER COMPONENTS
Drying chamber:
The drying chamber was made up highly polished wood wish consist of
three drying trays also made of wood, the material has been chosen since
wood is a poor conductor of heat and its smooth surface finish and also
heat loss by radiation is minimized.
Heating chamber
It consists of following components:
Cover plate, absorber plate, insulation.
Cover plate:
This is a transparent sheet used to cover the absorber, thereby preventing
dust and rain from coming in contact with the absorber, it also retard the
heat from escaping, common Materials used for cover plates are glass,
fibre glass, flexi glass, but the material used for this Project is glass.

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Absorber plate:
This is a metal painted black and placed below the cover to absorb, the
incident solar radiation transmitted by cover thereby heating the air
between it and the cover, here aluminium is chosen because its quick
response in absorption of solar radiation and also copper because of its
good ability to keep the absorbed solar radiation.
Insulation:
This is used to minimize heat loss from the system, it is under the
absorber plate, the insulator can withstand stagnation temperature, it is
fire resistant and not subject to out-going gassing and it is damageable by
moisture or insect, insulating materials are usually fibre glass, mineral
wool, Styrofoam and urethanes, but here Styrofoam was chosen.
3.2.3 THE ORIENTATION OF THE SOLAR COLLECTOR
The flat-plate solar collector was always tilted and oriented in such a way
that it receives maximum solar radiation during the desired season of
used. The best stationary orientation is due south in the northern
hemisphere and due north in southern hemisphere. Therefore, solar
collector in this work is oriented facing south and tilted at 17.11º to the
horizontal. This is approximately 10 º more than the local geographical
latitude (Abeokuta a location in Nigeria, 7.11ºN), which according to
(Adegoke and Bolaji 2000), is the best recommended orientation for
stationary absorber. This inclination is also to allow easy run off of water
and enhance air circulation.
3.3 OPERATION OF SOLAR FRUIT DRYER
The dryer is a passive system in the sense that it has no moving parts. It
is energized by the
sun’s rays entering through the collector glazing. The trapping of the rays
is enhanced by the inside surfaces of the collector that were painted black
and the trapped energy heats the air inside the collector. The greenhouse
effect achieved within the collector drives the air current through the
drying chamber. If the vents are open, the hot air rises and escapes
through the upper vent in the drying chamber while cooler air at ambient
temperature enters through the lower vent in the
collector. Therefore, an air current is maintained, as cooler air at a
temperature Ta enters through

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the lower vents and hot air at a temperature T e leaves through the upper
vent.
When the dryer contains no items to be dried, the incoming air at a
temperature ‘Ta’ has relative humidity ‘Ha’ and the out-going air at a
temperature ‘Te’, has a relative humidity ‘He’. Because Te > Ta and the
dryer contains no item, Ha > He. Thus there is tendency for the out-going
hot air to pick more moisture within the dryer as a result of the difference
between Ha and He. Therefore, insulation received is principally used in
increasing the affinity of the air in the dryer to pick moisture.
3.4 DESIGN
Inlent temperature
= 35-40°C
Outlet temperature
= 75-80°C
Blower Air
flowrate = 75 m3/hr
FIGURE 3

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FIGURE 4
FIGURE 5

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3.5 DESIGN CONSIDERATION
The designed and constructed solar dryer consists of two major
compartments or chambers being integrated together, the solar collector
compartment, which can also be referred to as the air heater, and the
drying chamber, designed to accommodate three layers of drying trays
on which the produces (or fruits) are placed for drying.
In this solar dryer constructed, the greenhouse effect and thermo siphon
principles are the Theoretical basis. There is an was done in the month of
April- May, the dryer was placed outside with the collector facing the
sun. The collector has been rigidly fixed to the dryer at an angle of 17.5°
to the horizontal to obtain approximately perpendicular beam of sun rays.
The drying chamber was loaded with chikoo and apple chips estimated
to weigh averagely 50g of 6mm and 5mm thickness respectively. Under
no load condition, the temperature of the
heated air inside the dryer, the collector chamber and the ambient air was
taken every one hour interval, starting from 9am to 6pm, and also in the
absence of an hygrometer two thermometers were used to measure the
relative humidity, where one thermometer has its sensor whirled with a
weak, with the weak touching water in a beaker to get the wet bulb
temperature , and the other thermometer provided the normal
temperature which gives the dry bulb temperature. The wet bulb and dry
bulb temperature were used to obtain the relative humidity on the
psychometric chart, this was done every one hour interval, starting from
9am to 6pm.
A digital thermometer was used for the temperature measurement in the
solar dryer ,the initial moisture content was measured using variation in
weight loss was measured using an electronic scale.

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CHAPTER 4
CALCULATION

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CHAPTER 4
1. Insolation on the Collector Surface Area :
A research obtained the value of insolation for Abeokuta i.e. average
daily radiation H on horizontal surface as; [10]
H =1350 W/m2
and average effective ratio of solar energy on tilted surface to that on the
horizontal surface R as;
R = 1.0035
Thus, insolation on the collector surface was obtained as
Ic = HT = HR = 1350 × 1.0035
= 1354 W/m2
2. Determination of Collector Area and Dimension :
The mass flow rate of air Ma was determined by taking volumetric flow
rate.
 Thus, volumetric flow rate of air V'a = 75 m3/hr.
V'a = 75/3600 = 0.02083 m3/s.
 Thus mass flow rate of air:
Ma = V’a × ρa
 Density of air ρa is taken as 1.21kg/m3
Ma = 0.02083 × 1.21 = 0.0252 kg/s
 Therefore, area of the collector AC
AC = (0.0252 × 1005 × 50)/(0.5 × 1354) = 1.75m2

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 The length of the solar collector (L) was taken as;
L = Ac/B = 1.75/1 = 1.75 m
Thus, the length of the solar collector was taken approximately as 1.75m.
Therefore, collector area was taken as (1.75 × 1) = 1.75 m2
3. Determination of the Base Insulator Thickness for the Collector :
 The rate of heat loss from air is equal to the rate of heat conduction
through the insulation. The following equation holds for the purpose
of the design.
maCp (T0 – Ti) = 10 × Ka(Ta - Ta)/tb
K = 0.04Wm-1K-1 which is the approximate thermal conductivity for
Glass wool.
T0 = 80ºC and Ti = Ta = 30ºC approximately
ma = 0.0252 Kgs-1
Cp = 1005 JKg-1K-1
and Ac = 1.75 m2
tb =[0.04 × 1.75 × (80-30)]/[0.1×.0252×1005×(80-30)] = 0.0270 =
= 2.70 cm
For the design, the thickness of the insulator was taken as 5 cm. The side
of the collector was made of wood, the loss through the side of the collector was
considered negligible.
4. Moisture loss (M.L.):
 M.L = (Mi – Mf)/ Mi
Where , Mi = mass of sample before drying
Mf = mass of sample after drying.

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For Chickoo :
M.L = (850 – 240)/ 850
= 71.76 %
For Banana :
M.L = (700 - 130)/ 700
= 81.42 %

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CHAPTER 5
FABRICATION
AND
ASSEMBLING

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CHAPTER 5
 The solar fruit dryer was constructed making use of locally available
and relatively cheap materials. Since the entire casing is made of wood
and the cover is glass, the major construction works is carpentry works
(joinery).
 The following tools were used in measuring and marking out on the
wooden planks:
 Carpenter’s pencil, Steel tapes (push-pull rule type)
 Steel meter rule, Vernier calliper.
 Steel square, Scriber.
 The following tools were also used during the construction;
 Hand saws (crosscut saw and ripsaw) , Jack plane.
 Wood chisel, Mallet.
 Hammer and pincers.
 The construction was made with simple butt joints using nails as
fasteners and glue (adhesive) where necessary. The construction was
sequenced as follows for the wood work:
 Collect three wood ply of 18 mm thickness.
 Marking out the lines as per the cutting requirement.
 Cutting out the already marked out parts.
 Planning of cut out parts to smoothen the surfaces.
 Joining and fastening of the cut out parts with nails and glues.

34
 Put four partition of wood on the base of heating chamber of 5 cm at
the equal interval. Filling the gap with glass wool as insulation of 5 cm.
FIGURE 6
 Covering the glass wool by the aluminium sheet of 27 gauge thickness
and sheet is fastened to the heating chamber. 5 passings are made by
placing wooden ply of 10 cm height on the aluminium sheet at the equal
interval.
 Equal length of slots are cut out at alternate ends in the wooden ply.
Cut out hole in the heating chamber at the entrance of the heating
chamber. The size of the hole is equal to the outlet of the blower.
Another hole is made in both the chamber for passing the air from
heating chamber to drying chamber directly.

35
 The alluminium sheet was used of 27 gauge thickness. It was cut to the
size of 175 × 100cm to minimize the top heat loss. It was painted black
with for maximum absorption and radiation of heat energy.
 All inner side of the drying chamber are covered with glass wool of 5
cm thickness for minimize the heat loss from the drying chamber and
glass wool is covered by the aluminium foil of 47 gauge.
 The glass was cut into size of 175 × 100 cm size. It is added as the solar
collector’s cover. It is fitted by the silicon glue for the air tightening the
chamber. The glass used was clear glass with 8 mm thickness.
FIGURE 7
 The trays were made with wooden frames permit free flow of air within
the drying cabinet (chamber). Three trays were used with average of

36
22.5 cm spacing arranged vertically one on top of the other, the tray size
was 50 × 86 cm.
 The interior of the solar fruit dryer was painted black to promote
absorption of heat energy. fit six wood strip for supporting the trays.
Make some holes in the roof of drying chamber for exhausting the hot
air in to the atmosphere.
FIGURE 8
Before Drying

37
 FINAL PROJECT PHOTO :
FIGURE 9
Intermediate Drying After Drying

38
CHAPTER 6
PROJECT
COST
CALCULATION

39
CHAPTER 6
 FABRICATION COST [C1]:
Wood Material = ₹ 5100
Extra work cost = ₹ 2100
 ALLUMINIUM SHEET [C2]:
Total cost of both the aluminium sheet = ₹ 960
 GLASS [C3]:
Cost of Glass, Silicon and Fitting = ₹ 2030
 TRAY [C4]:
Cost of the tray and it’s framing = ₹ 500
 PAINT AND SOLUTION [C5]:
Total cost of paint and solution = ₹ 300
 BLOWER [C6]:
Cost of blower = ₹ 500
 TRANSPORTATION COST [C7]:
Cost of transporting Model and Glass = ₹ 315
 EXTRA COST [C8]:
Extra cost = ₹ 200
 TOTAL COST [C] :
Total cost of Domestic Solar Fruit Chips Dryer =
C1 + C2 + C3 + C4 + C5 + C6 + C7 + C8 = ₹ 12005

40
CHAPTER 7
TESTING

41
CHAPTER 7
 As we describe earlier our basic purpose is to achieve70 to 80ºc
temperature at the inlet of the drying chamber and reduce moisture upto
minor level
 After assembling both the chamber , we fit the blower in the inlet of the
heating chamber.
 The required reading are taken as follows :
Without blower :
Ambient temperature = 35ºc
Outlet temperature of heating chamber = 70ºc
With blower : [25/04/2013]
TIME OF
DAY
AMBIENT
TEMP.
[ºC]
INLET TEMP.
OF DRYING
CHAMBER
[ºC]
INTERMEDIATE
TEMP. IN THE
DRYING
CHAMBER
[ºC]
EXIT TEMP.
[ºC]
10:00 A.M
35
75
68
60
11:00 A.M
38
80
73
63
12:00 A.M
40
84
75
66
1:00 P.M
39
80
72
64
2:00 P.M
39
78
70
63
3:00 P.M
38
76
68
63
4:00 P.M
35
70
62
55
With blower : [26/04/2013]
TIME OF
DAY
AMBIENT
TEMP.
[ºC]
INLET TEMP.
OF DRYING
CHAMBER
[ºC]
INTERMEDIATE
TEMP. IN THE
DRYING
CHAMBER
[ºC]
EXIT TEMP.
[ºC]
10:00 A.M
35
75
65
54
11:00 A.M
38
80
70
58
12:00 A.M
40
80
72
60
1:00 P.M
39
78
72
62
2:00 P.M
39
76
71
64
3:00 P.M
38
74
68
63
4:00 P.M
35
70
64
57
TABLE 5
 NOTE : These are the measured temperatures in our trial during
clear sky. This may vary according to atmospheric condition.

42
CHAPTER 8
CONCLUSION

43
CHAPTER 8
 The performance of existing solar fruit dryers can still be improved upon
especially in the aspect of reducing the drying time and probably storage
of heat energy within the system. Also, meteorological data should be
readily available to users of solar products to ensure maximum efficiency
and effectiveness of the system. Such information will probably guide a
local farmer on when to dry his agricultural produce and when not to dry
them.
 Solar radiation can be effectively utilized for drying of agricultural
produce in our environment if proper design is carried out. This was
demonstrated and the solar dryer designed and constructed exhibited
sufficient ability to dry agricultural produce most especially fruit items to
an appreciably reduced moisture level.
 This will go a long way in reducing fruit wastage and at the same time
fruit shortages, since it can be used extensively for majority of the
agricultural fruit crops. Apart from this, solar energy is required for its
operation which is readily available in the tropics, and it is also a clean
form of energy. It protects the environment and saves cost and time spent
on open sun drying of agricultural produce since it dries fruit items faster.
The fruit items are also well protected in the solar dryer than in the open
sun, thus minimizing the case of pest and insect attack and also
contamination.

44
CHAPTER 9
REFRENCES

45
CHAPTER 9
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