All over the world, the peak demand load is increasing and the load factor
of utility is decreasing year-by-year (Rahman et al., 2004). As,
the fossil fuel is considered insufficient, solar energy becomes more
important. By the help of the improvements concerning photovoltaic system
technology, the implementations to telecommunication, space studies, middle
grade energy manufacturing plants and operating irrigation pumps at rural
area without electricity (Mori, 2000). Nowadays, the utilization of solar
cells, which are used to supply electrical energy, has more and more investment
and branch of business (Argul et al., 2002). Solar-powered pumps
are available in a wide variety of configurations. If the water source
is a dugout, floating pumps are available. If the water source is a well,
submersible centrifugal pumps are often used. For dugouts, streams and
shallow wells, self-priming surface centrifugal or positive-displacement
pumps can be used. Whatever kind of pump is used, it is especially important
in low-voltage applications like solar energy that care is taken to ensure
that the pump is matched to head and discharge requirements of the application.
Furthermore, there are many advantages like mobility, silence, longevity
and lightness (Setaka et al., 2000).
Not only installation of a system but also monitoring and controlling
of that system are important. However, charging at least one of the operators
for this monitoring increase the costs alongside with the errors. The
costs are very important for small-scale applications. Generally, simple
calculations and installed monitoring-following systems are neglected
for small-scale applications in the designed systems (Rosenthal et
Through the widespread usage of internet has removed the distances and
has generalized the usage of e-technology on many applications. In consideration
of its having own network structure and accordingly having an advantage
on communication area, it has began to highlight internet based control
In this study, the target is to monitor and control a developed solar
pump system by using the available internet foundation. In this system,
java-programming language has been used. The main reason to choose this
||Because of its structure, it will be acceptable at many
platforms without any extra recovery
||It can be operated at long distant connections without any extra
software and hardware
||It can be connected during off-hours
||Its maintenance and reparation will be easy due to its limited number
Especially during installation stage, there will be no need to form a
communication line for data transfer so there will be no time waste and
it will be employment economy.
SUN TRACKING AND SOLAR PUMP SYSTEM
Tracking of solar collectors is an effective method to increase energy
yield (Teolan, 2008).
||Average sunbath time in application area.
For concentrated collectors (especially in desert
conditions), two-axes tracking systems are used effectively, as they are
most productive and relative cost of their drive is not so high compared
with the concentrator (Abdallah and Badran, 2008). For the region that
the system was built, the total average sunbath time where shown in Table
1 (Turkish Government Meteorology, 2008) per year which is 2520 h
(totally 6, 9 h day1) and the average total radiation
strength which is 1311 kWh m2 year1 (totally 3, 6 k Wh m2 day1) are detected.
On the basis of the data in the table, a prototype solar pump tracking
system has been developed and installed at the experimental site and connected
to a control station, placed near well. In this developed pump tracking
system, 2 items of 24 V Direct Current (DC) motor has been used and these
motors which are fed by the energy produced by PV Panels has also been
used for the movements of these panels. PIC16F877 microcontroller whose
effect to system cost is negligible has been used for controller. Besides,
PIC16F877 microcontroller has again been fed by the energy stored at PV
panels. Four items of LDR components have been separated into 2 groups
and have been located in order to sense the light through East-West, North-South
direction. The error signal has been produced through the voltage difference
of these components and the position error of the panels has been detected.
By means of the control method, the panels have gathered the sunlight
vertically. Therefore, independent from the geographical coordinates of
the system, it senses the sun light automatically and it can follow the
sun continuously in the view of the world`s cycle. The system can follow
the sun at vertical and horizontal axis. Figure 1 shows
the photograph of the movement mechanism of the sun tracking system at
the horizontal axis. The designed sun tracking system can track to sun
it at both vertical and horizontal axis during the day.
In order to tracking in the direction of East-West, an endless round
screw has been located to the bottom of the system. The voltage of LDR
components is set to be equal when the panel gathers the sunlight vertically.
In case of the panels did not gather the sunlight vertically, the voltage
on LDR whose resistances changes according to the sunlight. This voltage
difference detected by the analog inputs of PIC circuit is used to get
information about the direction and the reference speed for the motor
by undergoing it fuzzy logic controller, however, subject of this study
is not position control with fuzzy logic.
||General view of solar monitoring pump system
On the output of fuzzy logic
a direction, PIC micro controller transfers speed and cycle signal. These
signals collected from the power circuit have been used for running the
motor and turning the endless screw. By speeding down between the endless
screw and gear with the rate of 1:100 step differences, the torque has
been increased and the vibrations while the panel is getting to its reference
location have been reduced by the slow motion of the system. A dead zone
in PIC microcontroller has been defined for preventing the continuous
running and energy consumption of the motor, which turns the panels. Therefore,
the panels could monitor the sun light with maximum error margin of 1%.
System stops automatically when a cloud comes in front of the sun or
it gets darks and keeps that position until the sun light arises again.
As the sun rises, the system finds it in a 5 min period and starts running.
Figure 2 shows the photograph of solar pump system.
||The general structure of the sun monitoring system
INTERNET BASED MONITORING SYSTEM
In order to make an internet based monitoring system, the application area
has chosen to be a pump in an open use area with two solar panels. The basic
structure of the system can be seen in Fig. 3 and control system
can be shown in Fig. 4.
In order to observe and control the system while working, one computer
has been used and already present LAN line has connected it to the internet.
All the data observed and control functions have been performed from monitor.
It has been aimed the study to be observe through internet at will and
the communication and control functions to be done by the help of computer
ports. This developed solar pump monitoring system was designed by using
Java Program. Many sub programs have been used to improve the functionality
and the clarity of the program. The start point of the system is a file
Knowledge is the most valuable thing for foundations. In the foundations
defined with not only the employees but also customers, business partners
and part owners, it has a strategic importance to create the good faith
related to the knowledge conservation and confidence. Fast growing technology
and communication facilities present new potentialities for committing
crimes in electronic form while they bring along the solutions for knowledge
conservation (Filibeli et al., 2007). A probable security problem
in electronically form can prejudice the foundations by financial loss,
strategic knowledge loss, confidence loss and image loss. In order not
to have such losses, a firewall must be installed into the system.
Together with being essential, control through internet is a risky process
in the security and illegal people field. The units that will be under
control must be carefully observed. Concerning system security and business
principles, in real-time connections, it is not acceptable everyone to
freely enter and check variables.
||Control card view of solar monitoring system
||Password page for control and monitoring functions
As shown in Fig. 5 password page for real-time images,
graphs and controls which can be opened only by authorized people have
been designed. The user password and name are required for that page.
Password pages have been designed sufficiently protected against unauthorized
accesses. Hence, in order program passwords not to be cracked, an interface
has been improved and masking has done for saving the opened page. The
developed interface casually mixes the user name and password and sends
it to the main program. The help of the analyzer located in the main program
forms the right logic order. Therefore, passwords are hidden and the protection
against unauthorized accesses is provided. Considering the sensitivities
of the system, authorization is done only from the main computer, not
through the internet.
Solar panels do not hold line voltage at the output. The voltage obtained
from them should be made suitable for system voltage. For this reason,
an inverter circuit should assist the system. The inverter control form
in Fig. 6 appears after the authorization passwords was
entered and inverter control part located in the main form of real time
functions is selected.
The system can be start and stopped by use of the serial port of the
computer. The control authorizations that will bring the system into critical
levels or damage the system are principally avoided. The authorization
of running or stopping the system is used in case of a problem.
In order to put the real time controls in the practice, one of the ports
of serial, parallel or USB can be selected. The control circuit would
be as shown in Fig. 7 for USB port. At the application,
one optocoupler integrated has been used for each output signal. Thanks
to this, the port has been protected against backward and excessive current.
A simple camera mechanism has been installed in order the system to run
or to be observed. This installed mechanism is also moved into the internet
area. The view of that form is shown in Fig. 8.
As database and the past time oriented analyses is the principle for
Solar pump monitoring systems, past time-oriented camera reviewing is
sometimes required for security control. Under that circumstance, an assistant
program copies the view.
Some of the important properties of solar pump monitoring system is the
view or data save and monitoring punit.
||The inverter control form
||Simplified port circuit for real-time controls
||The view of real-time camera monitoring form
||Serial port data reader circuit
By means of the communication
system, it continuously deals with the programmable electronic units,
which are located in control units. In this way, it presents an opportunity
of high level of control and observation for the operators. These features
can be titled as real time data collection, failure state record, long-term
data save, state display of the control system and remote control.
In solar pump monitoring system, all data such as alarm limits and warning
notices are used to form data base parameters as a part of the configurations.
While, all the environmental units are physically keep up with solar pump
monitoring system by means of external device inter unit, the dynamic
data required for automatic control and monitoring the system are controlled
In the study, in order to save data into the data base file, the analog
signals must be instructed. Using Data Acquisition Card for instructing
only one analog signal increases the cost of the application. Using PIC16F877
microcontroller and the serials ports of the existing computer instead,
have reduced the cost and made it practical. Figure 9
shows the circuit diagram used for instructing an analog signal.
This circuit that was built for reading the numerical data from system
uses a com port by means of its ability to read a data easily. The R resistances
used here are to limit the voltage. Therefore, the port be protected in
case any possible corruption.
For the graphic program installed into the web browser, an inquiry from
the database is carried out by means of a java program located in the
||The last 24 h inverter output voltage graph
||The last 24 h inverter output current graph
After the java program completed that inquiry, it transfers the
results from the database to the graphic program with a two-second of
delay. The graphic program draws the desired graphs on the display screen.
The data interrogated by the java program from the database and then transferred
in to the graph, contains the coordinate information of the graphs that
will be drawn. By means of the graphical opportunities provided by the
java programming language, the coordinates are drawn in the web browser. Figure 10 shows the 24 h voltage graph. Here, the real
time connection to the database, where the measured values by serial port
data reader is written on, is provided and thanks to this, the changes
can be monitored.
While, studying on solar pump monitoring system, it is much more important
to save and monitor different data for the system efficiency. Monitoring
only the voltage or only the current is not sufficient to reach the real
results. Therefore, monitoring different data becomes important during
data monitoring process. For these reasons, system monitors both the voltage
and the current and presents them to the customer as graphical form. Figure
11 shows the 24 h past time and immediate current graphs.
In this study, the implementation of an internet based solar pump monitoring
system has been performed. Especially for solar panels which are used
with an increasing personal usage and the help of internet sub structure
has performed the control and monitoring of electrical manufacturing.
For any information (current, voltage, frequency etc.) availability and
efficiency of internet media and local network have been examined.
In internet based solar pump monitoring control system, in addition to
the information purposefully for quality, cost, efficiency and maintenance,
by means of the operator control, the system control and the statistical
information, these results below are achieved:
||Not handling the communication line especially on the
installation stage has provided employee and system economization.
||Maintenance and reparation have become much easier by means of the
utilization of the internet sub structure through communication and
||Control on the production has increased by means of illimitable
and wherever suitable monitoring.
||Effective treating to the failures has reduced the time for maintenance.
||As it is possible to reach the retrospective data, it is easier
to maintain the units which may possibly cause trouble by data examination
||It has been possible to increase the system efficiency.
||Because of the structure of the Java program, it is accepted on
many platforms without any editing. Therefore, there is no need to
select a platform for the connection.
||In long-range connections, it has been operated with the present
structure without any extra hardware and software needed.
||The connection has also been enabled at off-hours.
Authors thanks to managers and employees of Gazi University Scientific
Research Project Unit for all their contribution and support for this
study with the Project code of TEF 07/2004-03