Modeling and Simulation of a Novel Module for Thermoelectric Power Generation from Solar Photovoltaic Panels

Electricity is a basic need of humans in this modern era and plays a role of a backbone in our daily life as well as in the economic growth of a country. The efficiency of a power system is very important parameter which helps in analyzing its overall performance. So due to this reason effective and efficient utilization of solar energy is very important. Heat losses occurs in solar panels which reduces power output and hence overall efficiency is decreased. These heat losses can be utilized in such a way that works as waste heat recovery system. This system uses light and heat energy of the sun. When sunlight strikes the PN Junctions of solar PV panels, photovoltaic electricity is produced. Whereas, heat of sun and heat losses in the solar panels can be utilized and temperature difference is created by different means so as to generate electricity using thermoelectric cells (TEC) which works on the principle of Seebeck effect. Electricity generated from both sources can be common pooled and feed to the load either directly or it can be stored in batteries. This makes the system more effective and efficient. Keywords— Electricity, power generation, Seebeck effect, solar energy, solar panels.


INTRODUCTION
Electricity plays a major role in building the economy of a country. All the domestic, industrial, commercial and metropolitan areas need electricity for their daily operations. If the prices of electricity are low and it is available whole day without any interruption, then the products made by the industries or factories are large in quantity and cheap in price.
Pakistan is an under developed country, its economy is unstable and its energy sector is at continuous downfall. The resources available for electrical power generation are either not used properly or there is lack of facilities or there is absence of expertise to utilize it in an efficient and effective manner to generate electricity from it. Transmission losses in the existing outdated system, uncontrolled power theft, reduction of water available for hydroelectric power due to seasonal variations, increase in the prices of fuel has increased the difficulty in the system. There is a dip between the electricity generation and the demand so due to this reason we  During last five years, work has been done in the energy sector of Pakistan. From 2013 to 2018, 39 power projects were installed which added a capacity of 12,230 MW to the national grid [2]. The energy of the sun is due to continuously occurrence of nuclear fusion reactions. When hydrogen atoms specifically protium or deuterium or hydrogen and helium are forced to combine by some external agents (energy) it releases a tremendous amount of energy in a form of light, heat and sound along with hydrogen or helium as a byproduct. Individually, fusion produces less energy as compared to fission but due to the presence of abundant amount of hydrogen on the surface of sun. The overall energy produced due to fusion is more in the sun if compared with the fission reaction.
Ongrid system is directly connected to the regional or national grid to supply electricity generated by different sources locally through bi-directional meters. ON grid system doesn't possess battery backup system. When grid supply is properly working and is switched on, ON grid system will work but when the feeders in grid station are switched off, ON grid system willn't supply electricity to the national grid [3].
Off grid system generates electricity and supply it to its local load along with storage facility without connecting it to regional or national grid is called OFF grid system. OFF grid system is connected with the battery backup. It can be International Journal of Engineering Works Vol. 6, Issue 06, PP. 212-216, June 2019 www.ijew.io connected with renewable as well as non-renewable sources such as wind turbines, hydro-turbines and diesel generators etc. It can be used to generate as well as store electricity in case of emergency or in case of cloudy weather or at night [4].
Hybrid system, which has both features of ON Grid and battery backup is called hybrid system. This system is not only connected to the regional or national grid but also charges the battery at the same time. Electricity is fed to the grid through bi-directional meters [5].
There are different methods of generating electricity including electricity generation from fossil fuels [6], Solar thermal power generation using heliostates to through light on a receiver tank [7] or using Seebeck effect for electrical power generation [8].   Thermoelectric cells vary in size, depending upon power requirement [14]. The length and width of the cell is in range of 2.5 to 50 mm each and thickness is in range of 2.5 to 5 mm as shown in  When two thermoelectric cells are staked together with slight modifications in internal structure it is called two stage thermoelectric cell [15]. The efficiency of two stage thermoelectric cells is more than one stage thermoelectric cell [16]. Two stage thermoelectric cell is shown in Fig 5.

IV. SIMULATIONS AND RESULTS
All the parameters of thermoelectric cells are simulated in Simulink. The variation of the parameters of thermoelectric cell with the rise in the temperature difference is shown in Fig  11. It is clear that with the rise in temperature difference the value of Seebeck coefficient changes slightly, value of resistance increases linearly , value of thermal conductance also changes slighty whereas the value of power changes slightly in the start but rises ecponentially with the increase in temperature. Figure 11. Variation of the parameters of thermoelectric cell with the rise in temperature.
If we integrate power of twenty solar panels with the power generated by thermieletric cell then the contribution of each sourves is shown in the form of a table 1. The share of electrical power by each source is shown in Fig 12. It is clear that power generation from thermoeletric system is more than that of solar panels system.

CONCUSLION
It is concluded that with the increase in the temperature of solar panels, electrical power is reduced . So utilizing this temperature for electrical power generation by means of thermoelectric cells, we can increase the overall electrical power , by integrating both solar panels and thermoelectric cells. The overall output power is increased by adopting this method of integration of solar panels with thermoeletric cells.