Abstract
A solar timber kiln with the capacity to season 10kg (30
liter peak-volume) of lumber design, construct and used for seasoning of wood.
The kiln is to construct of a timber frame covered with Acrylic sheet on the
top and Lasani sheet on the sides & bottom. Two fans were fitted for air
venting. The kiln attained a maximum temperature of 10° above the ambient
temperature. The average efficiency of the heat collector an Acrylic sheet, The
solar kiln reduced timber drying time by 33%.
Declaration
It is certified that project report of final year project
titled “DESIGN AND FABRICATION OF SOLAR KILN’’ is our own work. The work
has not been presented elsewhere yet for any assessment. Where material has
been used from other sources it has been properly acknowledged / referred.
Samee ullah_________________
Zain Ul Abedin______________
Kamran Mujahid____________
Acknowledgment
All praises to Allah Almighty The Gracious, The Merciful,
Who has created this world of knowledge for us. He bestowed man with
intellectual power and understanding, and gave him spiritual insight, enabling
him to discover his “self”, know his creator through his wonders, and conquer
nature. Next to all His Messenger Hazrat Muhammad (SAW) who is an eternal torch
of guidance and knowledge for whole mankind.
We would like to express our deepest appreciation to all those who
provided us the possibility to complete this report. A special gratitude to our
project supervisor Engr Fahim Tahir
for his guidance and constant supervision as well as for providing
necessary information regarding the project & also for his support in
completing the project.
We would like to thank to Dr.Liaqat Ali Najmi
HOD-Mechanical, for providing us assistance in various problems encountered
during course of this project. We also like to acknowledge the assistance and
guidance extended to us by other faculty members.
We dedicate our project to our parents, who always pray for
us and it is all with their help that we are able to complete our project. We
are thankful to everyone who helped us during entire project, especially our
HOD-Mechanical Dr.Liaqat Ali Najmi, and respected teacher and project
supervisor Engr Fahim Tahir . It is all because of their help we have
been able to complete our work in time.
Completing this education journey is a true blessing and GOD
be the Glory! This success has not been achieved in isolation, and we grateful
to all those who provided prayer and support, contribution of time, and
guidance the education journey in last we grateful to my family and friends for
their inspiration, patience, love and understanding. May GOD bless all of
you!
Table of contents
List of
Figure
1. 1 Solar Kiln (Made in paint for concept…………………………….………. 3
1. 2 Components of Solar Kiln……………………………………….……… 4
2. 1 Schematic of a Solar Kiln……………………………………………… 12
2. 2 Solar Kiln Front View…………………………………………………..17
2. 3 Air Circulation System…………………………………….……………21
2. 4 Solar Kiln………………………………….…….…………………….22
3. 1 Wood Chamber of Solar Kiln……………………………………………24
3. 2 Rectangular Shape of Solar Kiln…………………………………………25
3. 3 Triangular Shape of the Solar Kiln……………………………………… 26
3. 4 Solar Kiln………………………………….……………………….….26
3.5
Front View of Solar Kiln…………………….……………………….….28
3. 6 Back View Solar Kiln……………………………………………….….28
3. 7 Side View of Solar Kiln………………………………………….….….29
3. 8 Top View of Solar Kiln…………………….………………………..….29
4. 1 Wood Cutting Machine……………………………………………...….30
4. 2
Hand-Saw ……………………………………………...……………. 31
4. 3 Acrylic Sheet………………………………………………………….31
4. 4 Wood Chamber……………………………………………………….32
4. 5 Acrylic Sheet………………………………………………………….34
4. 6 Fan & LDR Module………………………………………………...….34
4. 7 Humidity and
Temperature Sensor………………………………..…….35
4. 8 Insulation…………………………………………………………….36
4. 9 Arduino Uno………………………………………………………….37
4. 10 Lcd Display
(16×2) ………………………………………………….38
4.
11 Complete Assembly………………………………………………….39 Figure
5.1……………………………………………………………...…………….19
Figure
5.2……….…………………………………………………………………...20
List of Tables
Table 1……………………………………………………………….43
Table 2…………………………………………………………….…44
Abbreviation
EMC=Equilibrium
Moisture content.
SSS= Solar
system simulation.
SKS= Solar Kiln
simulation
CC= climate
chamber.
Chapter 1
Introduction
1.1Introduction to solar kiln
Drying of agricultural products is one of the applications
where solar energy can be efficiently utilized. The reason for this is that the
drying process requires low grade energy since high air temperature may damage
the dried material. Several investigators have proposed many geometries and
arrangement that use solar energy in drying. These geometries can be classified
into two types.[1]
Ø Solar collectors are used separately
to preheat the ambient air before it is supplied to the dying1
Ø The solar collector and the drying
are integrated is one structure.
In this system, ambient
air is first heated in the solar collector and is then circulated by natural
draft through the drying bin. [1]
Lumber is
usually dried to specific moisture content prior to further manufacturing or use.
The amount of water in wood is usually expressed as moisture content and can be
directly measured or calculated. The moisture content of wood is defined as the
ratio of the weight of water in wood to the dry weight of the wood material.
While lumber can be air-dried, the humidity in most localities prevents the
lumber from reaching the moisture content required for the stability needed for
interior use. A dry kiln is required to dry lumber to the necessary final
moisture content and does so fairly rapidly. This publication discusses the
design and operation of a solar-heated lumber dry kiln that is designed to be
inexpensive to construct and simple to operate. [1]
1. 1 Solar Kiln
Where;
Sun Radiation= sun light
direct incident with Acrylic Sheet
Ambient Air = inlet Air
to interior system of Solar Kiln
1.2Components of solar kiln
Solar Kiln Main component consists of
1. Acrylic Sheet
2. Fans (two-sets) and
Relay Control
3. Humidity and
Temperature Sensor
4. Arduino UNO
5. Lcd Display (16×2) and
Buttons for setting
6. Dc-Motor and shaft,
Battery (12V)
7. Insulation Sheet.
1.3 Acrylic Sheet
The acrylic sheet is
ceramic material with high temperature capability. Acrylic Sheet change the Sun
Light wave length, when sun light passed through it.
1.4 Fan and Relay Control
Fan used as exhaust of
Air. We used dc-fan in the Solar Kiln project because only for testing the
system. Relay Control used as ON/OFF switch.
1.5 Arduino Uno
There are a
number of different Arduino boards; we will be using one of the most popular,
the Arduin Uno.The Uno has a number of input ports which can be used to read in
signals from other Sensor and Fan, and output ports which can be used to drive
external lights, speakers, motors and LCD.
Arduino Uno Program:
// SOLAR KANAL PROJECT
// GROUP MEMBERS
#include <dht.h> // library file for dht11 sensor
#include<LiquidCrystal.h> //library file for lcd
LiquidCrystal lcd(13,12,8,9,10,11); // pins define for lcd
int relay=6; // pin
for fan on and off
int val; //
variable define
int pin=4; //
for ldr sensor
int led=2; // led
is used in pin 2
float var=0; //
variable used to store value
float var1=0; //
variable used to store value
int pin2=A0; // FOR
temperature sensor LM35
dht DHT;
// library file
#define DHT5_PIN 5
// pin define for Humidity sensor
void setup()
{
Serial.begin(9600); // serial communication
Serial.println("SOLAR KANAL
PROJECT");
Serial.print("Humidity
and temperature control ");
Serial.println();
Serial.println("\tHumidity (%),\tTemperature (C)");
lcd.begin(16,4); // lcd define
pinMode(relay,OUTPUT); //
fan output
pinMode(pin,INPUT); //
FOR IR SENSOR READ
pinMode(led,OUTPUT); // led
pin value as output
pinMode(DHT5_PIN,INPUT); // FOR
HUMIDITY SENSOR DHT11
pinMode(pin2,INPUT); // FOR
TEMPERATURE SENSOR LM35
}
void loop()
{
float reading=
analogRead(pin2);
float
temp=(reading*0.48828125);
Serial.print("DHT11,
\t");
float chk =
DHT.read11(DHT5_PIN); //READ VALUE FROM
DHT11 SENSOR PIN 5
{{
Serial.print("\t");
Serial.print(DHT.humidity, 1);
Serial.print(",\t");
Serial.println(temp);
// Serial.print("\t");
lcd.setCursor(0,0);
lcd.print("temp(C) = ");
//
lcd.setCursor(0,1);
lcd.print (temp);
lcd.setCursor(0,1);
lcd.print("Humidity %=");
lcd.print
(DHT.humidity);
}
delay(1000);
lcd.clear();
// conditions for on and off fan
// case 1 : when humidity >=60 and temperature is
>=25 then fan is on
if(DHT.humidity>=60 && temp>=35)
{
digitalWrite(relay,HIGH); // its a negative trigger relay (relay
light on at low trigger)
lcd.setCursor(0,0);
lcd.print("FAN
IS ON");
}
if(DHT.humidity>=60 && temp<=35)
{
digitalWrite(relay,HIGH);
// its a negative trigger relay (relay light on at low trigger)
lcd.setCursor(0,0);
lcd.print("FAN
IS ON");
}
if(DHT.humidity<60 && temp>=35)
{
digitalWrite(relay,HIGH); // its a negative trigger relay (relay
light on at low trigger)
lcd.setCursor(0,0);
lcd.print("FAN
IS ON");
}
// case 2
: when humidity >=60 and temperature is <25 then fan is on
if(DHT.humidity
<60 || temp<35)
{
digitalWrite(relay,LOW); //
fan high means voltage at pin is
high
lcd.setCursor(0,0);
lcd.print("FAN IS OFF");
}
delay(1000);
lcd.clear();
}
// coding for light detection
var=
digitalRead(pin); // read data from
digital pin
if (var>0) // if condition
{
digitalWrite(led,LOW);
lcd.setCursor(0,0);
lcd.print("LIGHT IS OFF
");
}
if (var==0)
{
digitalWrite(led,HIGH);
lcd.setCursor(0,0);
lcd.print("LIGHT
AVAILABLE");
}
delay(1000);
lcd.clear(); [[2]]
1.6 Humidity and Temperature Sensor
Humidity is the presence of water in air. The amount of water vapor in
air can affect human comfort as well as many manufacturing processes in
industries. One of the tasks of air-Exhausting, depending on the
existing internal and external effects, is to provide optimal temperature in
the Solar Kiln. Temperature sensors are integral components of Solar Kiln and
units. [[3]]
1.7 Dc-Motor
and shaft
Dc motor covert
electrical power to mechanical in the form of rotation in this system the dc
motor is rotate shaft and with help of shaft we can able to adjust the angle of
Acrylic Sheet.
1.8 Battery
Dc Battery (12Volt)
rechargeable li-Ion 6000mAh pack for Lcd, humidity & temperature sensor, to
drive Dc-Motor for negligible time to adjust the angle for Acrylic sheet.
1.9 Insulation
Insulation is to protect
every system from damage. This way here
we use it for to not direct effect the weather condition on the system of Solar
Kiln.[3]
1.10 Exhausting fan and ambient air inlet
Fig 1.1 shows to regulate
the air and temperature of the internal system and control it with achieved
target value.
1.11 Exhausting Fan
Exhaust fan is to control
the temperature in the internal system. When temperature is high in the
internal system from given target values, then the exhaust fan automatically
control the internal temperature. [3]
1.12 Ambient Air Inlet
The ambient air inlet
from the bottom of solar kiln is necessary to protect system from squeezing
condition, not affect the structure of the system also to protect material
(wood, corps) from damage. [3]
1.13 Advantages and disadvantages of solar kiln
1.14 Advantages
·
. 1) Drying time is significantly shorter than air drying.
·
2) Drying quality is
substantially better than air drying.
·
3) Drying to a very low
equilibrium moisture content (e.g. 8-10%) is possible for most locations,
compared with air drying.
·
4) The system has low operating costs (solar
energy, less fuel required for additional heating), and less skill is required
than for conventional kiln drying.[1]
1.15 Disadvantages
·
Solar
Kiln is more normally more expensive then air drying.
·
More
skill is required to them well.
·
Require
maintenance.
·
Solar kilns depend on weather conditions
(affected by rain, cloudy days)[3].
- Overall solar kiln is considered
as an acceptable alternative to air-drying method for pre-drying of
hardwoods (e.g. black butt, Eucalyptus pilularis). [[4]]
- So Australasian timber
industry is showing an increasing interest in use of solar kilns.Solar kilns
are ineffective for high production shops, but they certainly have their
place with serious hobbyists and individual furniture and cabinetmakers.[4]
Chapter 2
Literature
Review
2.1 Background
The earliest known kiln dates to
around 6000 BC, and was found at the Yarim Tepe site in modern Iraq[1]. As air is heated in the collector
space, one or more fans circulate it through the lumber, enabling it to absorb
moisture from the lumber’s surface. When the evaporated moisture increases the
relative humidity to where it gets too high in the chamber, it releases it
through vents in the back of the kiln. Solar
Kilns Managing Director, Greg Weir, is a second-generation Australian
saw-miller and timber processor with over 40 years’ experience in sawmill and
timber processing industry [6]. The
original model of this dryer was successfully built and used for years by
Curtis Johnson, a retired Forest Service employee [[5]]. A newer model designed by Mr.
Johnson with greater holding capacity and other improvements is now in
operation. Steinmann (1992) investigated the effects of collector area and
solar tracking on the performance of a solar wood drying kiln and came to the
following conclusions: Increasing the
collector ratio (collector area per volume wood in the kiln) from 2.4 to 12.1 m2/m
3 raised the average temperature by only 2°C, over the full drying
time [13]. The
solar simulation system as previously described (Steinmann 1990) was used to
simulate an actual drying run in a solar kiln. Adjustments necessary to
compensate for difference in scale are described [[6]]. The simulated weather conditions
were in close agreement with the actual weather. [[7]]
Solar-kiln drying gives a higher quality
of seasoned timber than open-air seasoning (Johnson, 1961). [4]
The main types of solar kiln include: the greenhouse type-(Plumptre, 1979),
semi-green-house (Young, 1979) and solar kiln with external collector
(Tschernitz & Simpson, 1979; ofi, 1982) [1]. The objective of this work was
to construct and test the performance of the simple solar kiln designed for
small-scale sawmills in tropical countries [Plumptre, R. A. (1983).[4] Some
thoughts on design and control of solar timber kiln. Paper presented to Wood
Drying Workshop of IUFRO Division V Conference, Madison, WI]7. The
solar kiln reduced the drying time of Terminalia Superba and Mansnia altissima
by a third when compared with the open-shed during the wet season (May-July)
this is reasonabily high when compared with earlier reports of dryers [Off,
1982; Duffle et al.,1974].[5]
The model was
validated experimentally for a box-type collector solar kiln operating under
constant and falling rate drying periods. It was found that although the model
could be applied satisfactorily, the tested design proved to be a very
inefficient one, giving low values for the recirculating parameter.[[8]]
The flow diagram illustrating the control logic of
this kiln is published elsewhere (Steinmann, Vermass 1990). The moisture
content of the kiln air, expressed as equilibrium moisture content (EMC), was
controlled according to a normal drying schedule based on the instantaneous
moisture content of the load. The control logic satisfied the following two
conditions:
·
Venting was allowed only if
EMC(I)>EMC(P) where EMC(P)= the target value for the equilibrium moisture
content inside the kiln [EMC (I)], according to the drying schedule.[13]
·
Venting should produce a net moisture
loss in the kiln air.
The temperature
and equilibrium moisture content of the air inside and outside the kiln were
measured and recoded at 5-min intervals, together with the solar radiation,
mass of the Kiln and air dryir loads, frequency of venting as well as spraying,
and the time, recorded by computer.[5]
2.2 The Finite Difference Equations
The
finite difference technique is used to solve the governing equations together
with their boundary conditions. An implicit method is used with the
Gauss-Seidel iterative technique. Computer search is carried out to determine
the space step AX and time step AT that give a unique solution which is
independent of the reduction in AX and Az. A convergence criterion that the
relative variation in the temperature of any nodal point should be less than 10
- 6 is used between any two successive iterations. A summary of the finite
difference equations is given in the Appendix.[6]
2.3 Solar Kiln Construction
The
solar kiln described by Steinmann et al. ( 1980, 1981 ) consisted of an
insulated chamber and an external collector facing north and inclined at 45 °
to the horizontal (latitude of the kiln site + 10°) for optimum year round
performance. Air was circulated over the collector and through the load at 1.7
m/sec -1.[6] Vents and a spray system were used
to control the relative humidity in the kiln. The temperature and relative
humidity of the air inside and outside the kiln, the mass of the kiln load, the
status of the venting system (open/closed), the moisture content of the kiln
load, the time of the day, and the solar radiation were recorded at 15 min
intervals.[4]
2.3.1 Solar Kiln Control:
In conventional kilns,
drying is controlled according to drying schedules. These specify the
temperature and relative humidity of the kiln air at any given wood moisture
content value. In a solar kiln, the maximum temperatures are approximately
50°C, last only for very short periods during each day, and are only achieved
when the wood is partially dry and can endure these temperatures [[9]]. Temperature control is not
necessary in solar wood drying kilns and, therefore, only the moisture content
of the kiln air has to be controlled according to the given drying schedule.
The relative humidity inside the solar kiln was computer controlled in such a
way that venting was only allowed if it rose above the target value as given by
the drying schedule and if, at the same time, the absolute humidity of the
outside air was less than the absolute humidity of the air inside the kiln [13]. If both conditions were not
satisfied simultaneously, venting was not allowed. This was to prevent air with
too high a moisture content from entering the kiln. With this control, venting
was optimized, preventing loss of energy [5]. Such a system would achieve
identical drying results using the same drying schedule under the same weather
conditions both in the solar kiln and the SS [8].
2.3.2 The simulation system:
Design:
The SS (Fig. 1) consisted of a commercial CC into which a SKS (Figs. 2 and 3) was placed. The mm long and with the same cross section as the lumber used in the solar kiln, comprised the SKS load. SKS was controlled in exactly the same way as the solar kiln. A single piece of wood, 500.[7]
The SS (Fig. 1) consisted of a commercial CC into which a SKS (Figs. 2 and 3) was placed. The mm long and with the same cross section as the lumber used in the solar kiln, comprised the SKS load. SKS was controlled in exactly the same way as the solar kiln. A single piece of wood, 500.[7]
2.3.3 Weather Simulation
The
temperature and relative humidity of the air outside the solar kiln could be
accurately simulated on a real-time basis in the CC. The solar energy input to
the SKS was simulated by a power transistor (50 watt max) mounted on a finned
heat sink, serving as the collector plate. This collector plate was placed
inside the SKS parallel and next to the window (Fig.1) allowing for the long
wave radiation losses that occur in a collector. The glass area of the window
could be adapted to simulate changes in collector area.[7]
The energy input, W (in
watts/m-2), under the glass cover of the solar kiln collector was calculated
using eqn (1) which is based on equations described by Kreider and Kreith (
1975 ) and Lunde (1980) [4]. The input data consisted of the
solar radiation recorded during a specific solar kiln run, taking into account
the angle of incidence, (i) of the solar radiation on the inclined collector,
and the fraction (P) of the radiation passing through the glass cover of the
collector at different angles of incidence. These values were multiplied by the
collector area, a, (m 2) as simulated in the SKS. These calculated W values
represent the target values for the output of the transistor on the collector
plate in the SKS and were stored together with the ambient temperature and
relative humidity values as obtained from the same solar kiln run to serve as
target values for the control of the CC (weather simulator). [4]
[4]
Where la = solar
intensity on a surface perpendicular to the radiation at any selected date and
time; i = angle of incidence between the solar radiation and the collector
surface at any selected date and time; and P is calculated according to equation
(2) below. The fraction, P, of the radiation passing through the glass cover of
the collector, was measured for the 5 mm thick glass cover of the solar kiln at
different angles of incidence (i) using a solar meter. At i = 90 ° the
radiation under the glass was taken as zero.
[4]
Equation (2) gives the
empirically determined mathematical relation t between P and i.
where
[5]
Note: r
is a At i = 90 ° the
radiation under the glass was taken as zero.
2.4 Conclusions
From the above evidence
it was concluded that the simulation system could produce real and repeatable
drying results and that meaningful real-time simulations are possible using
this equipment. Using this simulation system, Steinmann (1992) investigated the
effects of collector area and solar tracking on the performance of a solar wood
drying kiln and came to the following conclusions:[5]
Increasing the collector
ratio (collector area per volume wood in the kiln) from 2.4 to 12.1 m2/m
3 raised the average temperature by only 2°C, over the full drying
time. Maximum kiln temperatures were 10°C higher, but the minimum temperatures
were not increased being a function of the ambient night temperature. Increasing
the collector ratio from 2.4 to 7.3 m2/m 3 reduced the drying time by about
20%, but further increases in collector ratio produced no further improvement.
At a kiln site with latitude 35 ° or higher, solar tracking by the collector
doubles the daily collected energy, but has no effect in winter. Solar tracking
by the collector can reduce drying times in summer by between 13% and 21%.
Solar tracking about a vertical axis, with seasonal adjustments of the
collector angle with the horizontal axis, reduces the drying times as much as
full tracking.[7]
2.5 Components
1.
Vent Fan and Fan Motor
2.
Test Piece Led Vent
3.
Dry Bulb and Relative humidity Sensor
4.
Load cell and window
As
wood is a hygroscopic material, it will absorb moisture from, or lose moisture
to, the surrounding air until its moisture content is in equilibrium with the
surrounding air.
2.6 Mechanism
Solar
energy is the basic resource needed in the wood drying process of this Kiln.
Temperature of Kiln is increased with the absorption of sun heat into the kiln
the entry of heat energy of the sun take place from glazed clear screen and is
readily taken by the dark black internal chamber.[2]
The
solar kiln consist collector chamber where all the heated air is collected. Fan
running with help of electric power are used as tool for circulating the air
across the timber chamber. This process enables the heated air to evaporate the
water from wood and absorb it in the air itself. As a result of this absorption
the humid element of the air keep on increasing. When the chamber the certain
high level of humidity an automatic exhaustion process initiated where by the
hot humid air thrown out of the vents located of rear portion the solar kiln.[7]
2.6.1 Enhance Size solar Kiln Material
To
enhance the size of the solar kiln to understand that the basic ratio principle
for each 10 board feet of wood you will need a 1 square panel of the solar
energy for clear roof of the top of kiln number an area of solar screen is of
almost importance of the solar kiln if the area is to large it can cause over
drying or speeding up of the wood drying process. This may result in cracking
in splitting of timber. Similarly if the solar screen area is too little, it
can result in slow drying or even no drying at all because the required heating
temperature of the air will not be reached.[7]
2.6.2 Significant of Solar Kiln Angle
Significance feature of Solar Kiln design is the angle
of its roof this angle should be such that able to absorb right amount of sun
light from sun. The angle can be determined by using the latitude of the place
where the kiln will be placed for wood drying. The angle of solar panel or roof
should be modified according to movement of sun in different time of year.
2.6.3 Energy Measuring
As kiln temperatures are usually
higher than ambient temperatures; energy is lost from a kiln. These losses Are
at a maximum when {T (I) - T (O)} is at a maximum and this is the case when T
(I) reaches its peak value. [[10]]
·
The
temperature and humidity be observed on a working drying time.
·
All
features are depends upon weather condition.
2.6.4 The Circulation System
Wood drying required an equal
distribution of hot air throughout the drying chamber it’s therefore very
important to have some circulation mechanism in place for movement of the hot
air from the absorption area to the other parts of the in most of the solar
kiln design electric fans are installed at place which the highest temperatures
this allow the highest amount of heat transfer within the circular chamber.[[11]]
2.7 Solar Kiln
There are several types of solar
kilns, but they all generally rely on some type of solar collector to provide
the heat energy that evaporates the water in the lumber. Unlike solar heating
for an office or home, in lumber drying it’s not possible to reduce the heat
requirement to the point where solar heating can be competitive. When you’ve
got a certain amount of water to remove from a certain amount of wood, you need
a certain amount of total heat to do it, and that heat requirement can’t be
changed.[10]
Types of solar kiln design
All through the basic design of a
Solar Kiln remains that same some variation can divide it into different design
forms a few of them are provided below.
2.7.1 Compartment Kilns Design
Compartment-type kilns
are designed for a batch process in which the kiln is completely loaded or
charged with lumber in one operation, and the lumber remains stationary during
the entire drying cycle. Temperature and relative humidity are kept as uniform
as possible throughout the kiln, and they can be closely controlled over a wide
range of temperature and humidity.[10]
2.7.2 The Greenhouse Kiln Design
This is the basic form
solar kiln design based on greenhouse design it has a large chamber like a
greenhouse in contains a transparent screen with glazed on the top roof. It is
surrounded by three walls on side accept the north. The transparent screen is
made up of plastic material. This type of kiln loses a lot of heat energy from
collector walls and the plastic which is poor insulator. Therefore some time
manufacturers use double glazing sheet on the solar panel on the screen.[10]
2.7.2 The Semi-Greenhouse Design
This
type of solar kiln design contains one glazing screen on a roof and one on the
southern wall. All the other wall are totally opaque and do not let the heat
pass through them .they are made from highly insulating materials.as a
consequence the loss of heat energy from this type of solar kiln is minimized
it is mostly made from a wooden frame of play wood material .the collector of
semi greenhouse designed kiln is one of the most vital components of a system.[10]
Chapter 3
3.1 Design parameters
3.2 Solar kiln
The Width of Solar Kiln
is = 1.5 Feet.
The Length of Solar Kiln is = 2.5 Feet.
The Height of Solar Kiln is = 2.0 Feet.
3.3 Acrylic sheet
Acrylic Sheet which we put on sides of the Kiln is = 2 mm
thickness.
Acrylic Sheet which we put on Top of the Kiln is = 1.5-2mm thickness.
3.4 Temperature & humidity of
the solar kiln
- Humidity in summer is = 60 to 80 %
- Temperature in summer is = 40 0C
- Humidity in winter is = 40 to 70 %
- Temperature in winter is =
70C to 300C
3.5 Fan (two sets)
·
Four
Blades Fan, (As increasing number of Blades, Efficiency is also increases).
·
Fans;
micro blades, which is generally use in computer system.
3.6 Solar kiln design volume
3. 2 Solar Kiln [10]
3.4
Triangular Shape of the Solar Kiln[10]
From the figure 3.1 above we can find out total volume and area of
solar kiln chamber:
For volume= V1
V1= width×
length× thickness
V1 = .724m×.305m×.419m
V1 = 0.0925 m3
For volume =V2
V2 = ½ (.419m) (.724m)
(.305m)
V2=.04625m3
Therefore total volume of the Solar Kiln
VTotal=V1+V2
VTotal= (.0925m3)
+ (.04625m3)
VTotal=13785m3
Now density of Sisso (tree) δ=800kg/m3
δ =m/v therefor m=Î´× v
m= (.13875m3) (800kg/m3) = 111kg
Total mass capacity of Solar Kiln for Sisso (tree)
mTotal = 111kg
3.7 Drying days (wood
& crops)
Minimum 6 to 13 days, but if we want more better result than
45 days are maximum period. Wood seasoning depends on wood quality types for example
Kail tree and Parthal tree. Kail trees are mostly used for doors and window
whereas Parthal also used for doors and window, for industrial purpose.
·
Capacity
of wood chamber is = 111kg (Peak-volume) of lumber.
·
4
to 6 board piece of (wood) length and thickness, 24 inch 1.2 inch and width is 12inche respectively.
·
We
not interested to finding, the wavelength of the sun light which is passing
through Acrylic Sheet, and Sun light is 1000 Wabers per square meter.
3.8
Solid work
Chapter 4
Fabrication
of Solar Kiln
4.1 Fabrication:
Solar Kiln fabrication is the
building of Wood (lasani) structures by cutting, joints, and
assembling processes. It is a value added process to achieve the wood Chamber
by cutting wood and Acrylic Sheet. Cutting (machine wood) and Hand Saw use in
manufacturing of Solar Kiln: [2]
Ø Cutting (wood machine).
Ø Hand saw.
4.2 Cutting (wood machine)
process:
Sheets (Lasani & Acrylic) available
in market are in different sizes as compare with our required size so cutting
machine used for cutting sheet for required shapes. Usually, measured the point
where the cutting action takes place and perpendicular to the direction of
blade movement.[7]
4.3 Hand saw:
It is simple way to cutting the wood
(Lasani) by human effort. By utilizing human force energy to achieved the
required objective. The
picture above is the picture of the handsaw and as we all know handsaw's go
back in history a long ways. Your grandfather or great-grandfather's use
handsaw is to build most of their projects before power tools.
4.4 Joint process:
In this
type of joint process we add Wood lasani & Acrylic Sheet to the joint and
prepared the simple Solar Kiln chamber. Used for joining for following parts
Ø
Wood Lasani
Ø
Acrylic sheet
4.
3 Wood Chamber
4.5 Material
We are using wood sheet & Acrylic
sheet for fabrication of different parts of Solar Kiln chamber.
As
Their main properties are given
Ø Wood chamber
Ø Acrylic sheet
4.6 Tool and instrument used
Ø Vernier caliper
Ø Measuring tape
Ø Hammer
4.7 Components
- Acrylic Sheet
- Fans (two-sets) and Relay Control
- Humidity and Temperature Sensor
- Arduino UNO
- LCD Display (16×2)
- Battery (12V)
- Insulation Sheet
4.8 Acrylic Sheet:
The acrylic sheet is ceramic material with
high temperature capability. Acrylic Sheet change the Sun Light wave length,
when sun light passed through it. Clear cast acrylic, also
commonly referred to as Perspex Sheet, is a high quality and versatile clear
plastic sheet material offering high levels of strength and clarity. Suitable
for many applications, cast acrylic sheet is an easy material to work with.
Cast acrylic is
one of the hardest thermoplastic sheet materials available and its attractive
aesthetics remain for longer than other plastic sheet materials. Cast acrylic is
manufactured by pouring monomer between two sheets of high quality glass and polymerized
in batches in a carefully controlled manufacturing process; Clear cast acrylic has
an exceptionally high level of light transmission allowing 92% of all visible
light through the material creating an unparalleled crystal clear finish. Not
even glass can achieve this level of optical clarity. Because of this clear
cast acrylic is an excellent alternative to glass for glazing purposes.
4. 5 Acrylic Sheet
4.9 Fans (Two-Sets) and Relay Control:
Fan used as exhaust of Air. We used
dc-fan in the Solar Kiln project Relay Control used as ON/OFF switch.
4.10 Humidity and Temperature Sensor:
Humidity
is the presence of water vapor in air. The amount of water vapor in
air can affect human comfort as well as many manufacturing processes in
industries. One of the
tasks of air-Exhausting, depending on the existing internal and external
effects, is to provide optimal temperature in the Solar Kiln. Temperature
sensors are integral components of Solar Kiln units2.
4. 7 Humidity and Temperature Sensor
4.12 Battery:
Dc-battery
(12volt) rechargeable li-ion 6000mah pack for lcd, humidity & temperature
sensors, a rechargeable battery, storage battery, secondary cell, or accumulator is a
type of electrical battery which can be charged, discharged into
a load, and recharged many times, while a non-rechargeable or primary
battery is supplied fully
charged, and discarded once discharged. it is composed of one or more electrochemical cells.
The
term "accumulator" is used as it accumulates and stores
energy through a reversible electrochemical reaction.
Rechargeable batteries are produced in many different shapes and sizes, ranging
from button cells to
megawatt systems connected to stabilize an electrical distribution network.
several different combinations of electrode materials and electrolytes are used, including lead–acid, nickel cadmium (nicd), nickel metal hydride (nimh), lithium ion (li-ion),
and lithium ion polymer (li-ion polymer).
Rechargeable
batteries typically initially cost more than disposable batteries, but have a much lower total cost of ownership and environmental impact, as they can be recharged
inexpensively many times before they need replacing. some rechargeable battery
types are available in the same sizes and
voltages as disposable types, and can be used interchangeably with them. [[12]]
4.13 Insulation:
Insulation is to protect every system
from damage. This way here we use it for
to not direct effect the weather condition on the system of Solar Kiln. Knauf Insulation Black Acoustical Board with ECOSE®
Technology is designed for use as acoustical insulation and/or a visual barrier
on walls and ceilings, where system design requires a rigid product and where
additional strength and abuse resistance are required[13]. The black surface provides a visual
barrier with an aesthetic appearance, in both wall and ceiling applications.
The product is typically used where framing members are not present.
4.14 Arduino Uno:
There are a number of different Arduino boards;
we will be using one of the most popular, the Arduin Uno. The Arduino Uno
has a number of
input ports which can be used to read a signal from other Sensor and Fan, and
output ports which can be used to drive external lights, speakers, motors and
LCD.
Arduino/Genuino Uno is a microcontroller board based on the ATmega328P (datasheet).
It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6
analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP
header and a reset button11. It contains
everything needed to support the microcontroller; simply connect it to a
computer with a USB cable or power it with a AC-to-DC adapter or battery to get
started. You can tinker with your UNO without warring too much about doing
something wrong, worst case scenario you can replace the chip for a few dollars
and start over again.
4.15 Lcd Display (16×2)
In
this project we are using LCD for to show us humidity and temperature
respectively. It has 16 column and 2 rows. We
need to solder the header pins to the LCD display,the header pins i
have are 2.0mm and you need the 2.5mm pins to fit the LCD display, so mine didn't fit
because they were to close together, so i decided to cut my header pins into
groups of 2,after i cut them into groups of 2, i could put 1 group of 2 in 2
pins, when you insert them, turn the display over and apply a small amount
of solder to each terminal, ensuring that
all the terminals are soldered, they should all be the same length, not bent,
loose or too short.[10]
4.16 Assembly:
We assemble all parts together by
joints. And nails are used to supports together two joints. The
ends of the wood were painted with leftover stain to reduce over-drying of the
wood near the ends.11 The wood is stacked in the kiln
with spacers between the boards called stickers. I stapled some Tyvek
cloth between the bases of the metal panels and laid it across the top of wood
stack to direct air through the stack. Concrete blocks were also placed
on the wood to reduce any wood bending.
4.17 Complete assembly of solar
kiln
It’s important
to locate the kiln with a south-facing exposure that’s free of shadows. I set
down treated landscape timbers to hold the kiln up off the ground (Photo 1).
The timbers provide a level platform for the kiln to rest on. we started by
securing the floor to the timbers, then added the back and sides . After attaching
the fan plenum to cleats mounted on the side panels, we drilled a hole for the
fan cord. Finally, the kiln was ready for loading. All we needed was some green
wood to dry10.
Chapter
5
Experimentation and Results
5.1 For the first day experimental value
|
Experiment
Time PM
|
Time
in
mints
|
Ambient temperature
|
System temperature
|
Ambient
Humidity
|
System Humidity
|
Fan
On Time
|
Number
of
Experiments
|
|
1:30
|
30
mints
|
25
C0
|
47.32
C0
|
27.5%
|
22%
|
3:12
sec
|
01
|
|
2:00
|
30 mints
|
25
C0
|
46.69
C0
|
33.12%
|
20.26%
|
2
mints
|
02
|
|
2:30
|
30 mints
|
26
C0
|
46.12
C0
|
24.11%
|
18.96%
|
3:34
second
|
03
|
|
3:00
|
30 mints
|
26
C0
|
47.32
C0
|
31.63%
|
17.26%
|
2:34
second
|
04
|
Table 5.1
Note:
In the start of experiment, the weight of wood was
10.6 kg. After two hours due to loss of humidity the weight of wood we weighed
was 10 kg. We observed that for 2 hours, the loss of weight of wood was 0.6 kg.
5.1 Figure
5.2 For the second day
experimental values
Table
5.2
|
Experiment Time PM
|
Time in
mints
|
Ambient temperature
|
System temperature
|
Ambient Humidity
|
System Humidity
|
Fan On Time
|
Number of
Experiments
|
|
1:30
|
30
|
29 C0
|
49.32
C0
|
21.5%
|
22.23%
|
3:16
seconds
|
01
|
|
2:05
|
30
|
27.7
C0
|
46.13
C0
|
20.5%
|
18.12%
|
3:00
mints
|
02
|
|
2:40
|
30
|
26 C0
|
47.87
C0
|
22.5%
|
17.87%
|
1:35
seconds
|
03
|
|
3:10
|
30
|
25 C0
|
48.32C0
|
21.5%
|
16.92%
|
2
mints
|
04
|
Note: In the start of
experiment, the weight of wood was 10 kg. After two hours due to loss of humidity
the weight of wood we weighed was 9.5 kg. We observed that for 2 hours, the
loss of weight of wood was 0.5 kg.
5.3 Results of two days
experiments:
We
put total 10.6kg Wood tiles in solar kiln for wood seasoning, As wood is a hygroscopic material, it will adsorb
moisture from, or lose moisture to, the surrounding air until its moisture
content is in equilibrium with the surrounding air.
5.3.1
first day:
In
the start of experiment, the weight of wood was 10.6 kg. After two hours due to
loss of humidity the weight of wood we weighed was 10 kg. We observed that for
2 hours, the loss of weight of wood was 0.6 kg.
5.3.2 On second day:
In
the start of experiment, the weight of wood was 10 kg. After two hours due to
loss of humidity the weight of wood we weighed was 9.5 kg. We observed that for
2 hours, the loss of weight of wood was 0.5 kg.
Chapter
06
Safety and Hazards
Any
organization cannot survive without any safety consideration. It is very
important for an
organization to safeguard the health and welfare of its employees and the
general public. Safety
should be in good practice; the good management practices needed to ensure the
safe operations in the organization that has an impact of efficient operations.
The term loss prevention
refers having loss in financial caused by an accident. This loss is not
only considered by replacing the cost of damaged plant and third party claims,
but also the loss of earnings from lost production and lost sales opportunity.All
manufacturing processes are to some extent hazardous, but in chemical processes
there are
no. of hazards associated with the chemicals, equipment’s and operations. The
designer must
be aware of these hazards, and ensure, through the application of sound
engineering practice,
that the risks are reduced to acceptable levels.
6.1 Sources of sun-light on acrylic sheet:
Precautions
must be taken in order to eliminate sources of sunlight on Acrylic Sheet to the
wood chamber. It is
best way to work on the principle of flammable material like
oil wood or other agricultural products etc.
6. 2 Electrical equipment:
The sparking of
electrical equipment, such as temperature and humidity sensor and lcd , arduino
uno, is a major potential source of ignition, and flame proof
equipment is normally specified. Electrically operated instruments,
controllers and computer systems are also potential sources of ignition of flammable
mixtures.
6.3 Vent Air
When designing
relief venting systems it is important to ensure that flammable or temperature
and humidity are vented from wood drying chamber. This will normally mean
venting at a sufficient rate values of temperature and humidity that prevents
solar kiln from squeezing.
6.3.1 Temperature deviations
Temperature
deviations can cause a major accident in any plant operation. Excessive high temperature can
cause structural failure and initiate disaster. High temperature can cause wood cracks.
The protection
can be taken to avoid high temperature by:
1. Provision of
high-temperature alarms and electronics controls devises to overcome the high
temperature and humidity.
2. Provision of
emergency cooling systems for solar kiln wood chamber, where heat continues to
be generated
after shut-down; for instance, in some polymerization systems.
3. Structural design of equipment to withstand the worst possible temperature excursion.
4. The selection of intrinsically safe heating systems for hazardous materials.
3. Structural design of equipment to withstand the worst possible temperature excursion.
4. The selection of intrinsically safe heating systems for hazardous materials.
Conclusion
- In solar kiln we try to save
the wood from the damage and cracks
- In solar kiln we dry the wood
as fast as we can.
- We maintain the temperature
and humidity of solar kiln from giving the specific range.
- In cold weather the dryness
of wood is difficult so with the help of solar kiln we easily dry wood
- Drying times were 3 to 4
months from initial (43 to 62%) to final MC (12 to 22%).
Recommendations for Future Work
Based on the present study the
following recommendations are made for future study
1. The produced seasoning of wood or agricultural products should be used for furniture’s etc.
1. The produced seasoning of wood or agricultural products should be used for furniture’s etc.
2.
All of the above scope of study we can say that wood and agricultural products
are mostly used for homes offices and industrial uses for burning.
Summary
Solar kilns are ideal for the hobbyist or professional
woodworker who wants to save money by drying his own lumber. Solar kilns are
relatively inexpensive to build and simple to operate. They use the free energy
of the sun, so they cost nothing to operate except for the small cost of
electricity needed to run the fans. Additionally, they are good for the
environment since they generate zero CO² emissions.
Although solar kilns are designed to keep the wood
from drying too rapidly, it is wise to check the MC level, especially near the
end of the drying cycle. It’s also recommended that woodworkers who are new to
drying lumber in a solar kiln or who are drying wood thicker than one inch
frequently check the moisture levels to prevent defects later on. A moisture
meter is a woodworker’s best insurance for solar-dried lumber to prevent
cracking, warping, or splitting in the finished wood product.
References
[1] ADNAN H. ZAHID and
MOUSTAFA M. ELSAYED August 1988.& http://owic.oregonstate.edu/solarkiln/plans.htm.
[3] Dr wengret 1978 Spa
Depot, spadepot.com, 800-823-3638, Outdoor Electronic 24-Hour Timer w/ Single
Outlet, #BX9982.
[5] .D. E.
STEINMANN*Department of Wood Science, University of Stellenbosch, Private Bag X5018, Stellenbosch, 7599,
South Africa
[6] D. E. Steinmann
Department of Wood Science, Faculty of Forestry, University of Stellenbosch,
Stellenbosch 7600, South Africa.
[7] By
Duffle, Y. A. & Beckman,. (1974) in New york.
[9] D.
E. Steinmann Department of Wood Science, Faculty of Forestry, University of
Stellenbosch, Stellenbosch 7600, South Africa.
[10] Steinmann,
D. E., The effect of collector area and solar tracking on the performance of a
solar lumber drying kiln. Proceedings 3rd IUFRO International Wood Drying
Conference, Vienna, Austria, 283-291 (1992)
[13] R.
M. Polak, L. L. Christianson and M. A. Hellickson,Grain drying with a solar
energy intensifier—simulation and validation. ASAE Technical paper 81-3517
(I981).
thanks for sharing most informative article i read complete article thanks
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