Agriculture is a significant measure of an economy for a number of countries in the world. Currently, the agriculture sector relies heavily on conventional sources of energy for irrigation and other purposes. When, considering factors such as increasing costs of fossil fuels and extending new power lines, especially to remote locations where grid electricity is either inaccessible or expensive, a solar PV (photovoltaic) irrigation system can be an effective choice for irrigating farmland. Solar power eliminates the need to run electrical power lines to remote agriculture locations, which quickly turns the monetary equation in favor of solar irrigation over grid-powered irrigation. In addition, the cost of delivering fossil fuels to remote locations can be expensive. Solar power is ideal for agricultural irrigation, as most irrigation is required when the sun is shining brightly. Consequently, a PV powered irrigation system is a promising technology that could help meet the irrigation needs of remote agricultural.
The two major goals of this research are to get an existing solar PV irrigation system working and to acquire experimental data using this system under various operating conditions. This research work is built upon a series of three senior design projects. These three senior design projects were to design and construct a solar irrigation system, an instrumentation system for this solar irrigation system, and a single axis solar translator. Specifically this thesis work entailed getting the instrumentation system to work properly, writing a LabVIEW program to automatically acquire data from installed sensors, integrating all three of these senior design projects into one PV irrigation system, getting the PV irrigation system installed on the roof of the Russ Engineering Building, and collecting a large amount of data on the system. All have been accomplished successfully.
The PV irrigation system work presented in this thesis use two 224 watt PV modules that are connected in parallel and mounted on a vertical axis solar tracker that follows the sun from east to west to enhance the amount of solar energy collected during the day. Energy developed by these panels is stored in two 100 amp-hour batteries wired in a series arrangement. Energy stored in the batteries is supplied to a direct current water pump that requires 50 watts of power at 24 volts. To harvest maximum energy from the PV modules and to protect the batteries, a MPPT-charge controller (maximum power point tracker with charge controller) is installed inline between the PV array and batteries. The instrumentation or DAQ (data acquisition) system employed on the PV irrigation system consists of four current sensors, four voltage transducers, four thermocouples, a pyranometer and a flowrate sensor to record associated parameters at various points throughout the PV irrigation system. The DAQ system is structured in such a way that each component’s output can be monitored and assessed throughout the system via a LabVIEW program developed as part of this thesis work.
This PV irrigation system has been investigated under four operating configurations. Three of the operating configurations vary the orientation of the PV panels and one operating configuration varies the load on the system. The four configurations tested are:
1. azimuthal solar tracking at an inclination angle of 40o with both the water pump and power dissipating resistors being used to consume the power generated by the PV array,
2. azimuthal solar tracking at an inclination angle of 30o with both the water pump and power dissipating resistors being used to consume the power generated by the PV array,
3. a fixed solar array pointing due south at an inclination angle of 40o with both the water pump and power dissipating resistors being used to consume the power generated by the PV array, and
4. azimuthal solar tracking at an inclination angle of 40o with only the water pump being used to consume the power generated by the PV array, where the water pump is run 24 hours a day.
A large number of measured quantities are presented for each of these configurations for the time period from July 28 to September 1st, 2014 in Dayton, Ohio.