الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 174 |  |  |
| | | from | 174 | | |
Abstract
The biggest challenges interfacing the world today are the Energy demand and environmental pollution. Thermoelectric generator is a promising technology that can help to overcome these challenges. They can convert heat energy from waste heat energy sources or renewable heat energy sources (such as solar energy and geothermal energy) to DC electrical power depending on the thermoelectric effects. Thermoelectric Generator (TEG) not only generate electrical power, but also improve the efficiency of the system implemented in by recovering the waste heat. Additionally, it’s a modular and solid-state device which operate in silent without any noise or maintenance. As it can utilize heat from variety of sources including solar, geothermal or waste heat energy from industrial plants or transportations, it is not limited by few sources of energy or environmental conditions like weather. Furthermore, it doesn’t produce any harmful emissions. These make this renewable technology very attractive.
In this study, TEG test bench has been designed and implemented to simulate the different operating conditions of waste heat energy sources. TEG test bench with different forming of the hot side and cold side heat exchangers have been designed and tested to select the optimal design of the heat exchangers. The proposed thermoelectric generator (TEG) system has been modelled and simulated using MATLAB-Simulink. It’s, also, implemented using Arduino microcontroller. Two different types of the commercial TEG modules (HZ-14HV and TEG 127-250-38) have been used in this study to verify the proposed system.
A DC-DC boost converter with a simple control algorithm has been proposed to characterize the TEG modules by obtaining V-I and P-I characteristics and extract the maximum power point (MPP) of the TEG module. The electrical performance of the TEG modules have been analyzed. Various dynamic parameters such as Seebeck coefficient, internal resistance of the TEG module have been estimated at this MPP as well.
The incremental conductance (INC) and Perturb and Observe (P&O) maximum power point tracking (MPPT) algorithms are the most popular techniques applied to maximize the output power in photovoltaic (PV) systems. They have been proposed to maximize the output electrical power of the TEG system. They are, also, simulated and tested at different operating condition and compared with the direct connection of the TEG to the load without applying the MPPT control algorithm.
The electrical performance of the TEG modules during the series and parallel connections has been tested and analyzed at different values of the applied temperature. A DC-DC boost converter with a simple control algorithm has been proposed to test two commercial TEG modules (HZ-14HV) and (TEG-127-250-38) when they are connected in series and parallel form at the same operating conditions.
In all tests, An Arduino microcontroller has been proposed to control the DC-DC boost converter to characterize and estimate dynamic parameters of the TEG modules at single, series or parallel forms of connection. It’s also used to maximize the output power of the TEG module with two MPPT algorithms. Moreover, it is used as a data acquisition system to measure voltage, current, hot and cold sides’ temperature of the TEG modules.
The outcomes of the Simulation and experimental results in all tests have been compared with the manufacturing datasheets. Simulation and experimental results for characterizing and testing a single TEG module show that, the TEG testing system has achieved the electrical characteristics and find the actual MPP which is used to estimate the dynamic parameters.
Simulation and experimental results for maximizing the output power of the TEG system show that, the harvested power duplicated by more than six times using the two MPPT algorithms applied in comparing with the connection without MPPT at the same operating condition. Also, Simulation and experimental results show that, the experimental TEG system and simulation model have maximized the electrical output power of the TEG module with good accuracy and faster response to track the MPP at rapid changes of temperature on both sides of the module. Also, results show that the maximum efficiency of the INC-MPPT was around 98% while the maximum efficiency of the P&O-MPPT was around 96.78% for the experimental results. While at simulation results, the maximum efficiency of the INC-MPPT and P&O-MPPT were around 98.6% and around 99.52% respectively, depending on the temperature differences applied on the TEG module.
For series and parallel connections, the experimental results show that, the dynamic parameters of the TEG modules affected greatly by the form of connection, which directly affects the output power of the TEG system. Also,
The experimental results show that, the DROP values of (ZK=α^2/R_int ) have been dropped by 30.9% for the series connection and 50.5% for the parallel connection. The total average output power has been dropped by 29% for the series connection and 49% for the parallel connections, which mean that the output power directly depends on the form of connection (the ZK ratio). Also, from experimental results, the DROP value in the output current in the parallel connection is greater than the output current in the series connection this may be due to increasing the values of total internal resistance in the parallel connection by 46%, while they have been increased by 21.7% in the series connections comparing to the data sheet internal resistance values at the same values of temperature.
Finally, the proposed model is efficient for using in studying TEG with a different power electronic converters and different control algorithms for small and large-scale TEG power generation systems. Also, experimental results show that, the proposed DC-DC boost converter with the proposed control algorithms are helpful for testing the commercial TEG modules before implementing in the TEG systems. Also, the output power of the TEG modules affected greatly by the form of connection (series or parallel). Series connection is more effective in harvesting TEG power than parallel connection. However, the two ways of connection result in a DROP of the output power than theoretical total power calculated from connecting single module power.