چكيده به لاتين
There is still an obvious and indisputable need for an increase in the efficiency of energy utilization in buildings. In order to decrease energy consumption and CO2 emissions In Iraq, due to the harsh climate, residential building consumes a high amount of energy, especially in summer. On the other hand, although there is an increase in electricity generation in Iraq but, there is an increase in electric demand especially in the last decade. This leads to periodic cut-off in the power in order to supply it for the largest number of cities almost equally. The aims of this work are to investigate the performance and design of a model of a Thermal Photovoltaic (PV/T) system numerically and test its suitability with Iraqi climates in order to electricity supply and domestic hot water for a typical residential building located in Basra city, south of Iraq. The investigating part was done in the Research Institute of Petroleum in Tehran, in order to study the effect of the solar radiations, inlet flow water and ambient temperature on the performance of the PVT/water experimentally. All related numerical analysis and validation were done by using ANSYS Software (CFD). The experimental results proved that as the radiation level and the water temperature at the inlet increased, the system’s electrical, thermal, overall, and exergy efficiency decreased. Achieving this goal requires choosing the appropriate flow configurations and working fluid. Four types of flow configurations (6,8,10 and double spiral flow) and two types of weight fraction of (3wt and 6wt) (PVT/Al2O3-water) (PVT/TiO2-water) and hybrid nano-fluid (PVT/Al2O3- TiO2- water). The results show that the double spiral flow configurations is the better than the other when takes the water as working fluid. Where, the maximum electrical and thermal efficiency reached (14.863, 34.55) % respectively. Thus, there is enhancement in the electrical and thermal efficiency about 9.5%, 4.23%, 1.12 % compared with (6,8,10 tubes based PVT system). In the other hand, the results clarified when adding 6wt% of the hybrid nanofluid (Al2O3- TiO2- water) as working fluid the electrical and thermal efficiency of the double spiral PVT is reached 19.16% and 63.98% % respectively. While the electrical and thermal efficiency of the 6wt% (Al2O3- water) are (13.56%,50.71%), meanwhile for the (TiO2-water) PVT system are: 11.34%,38.79%) in a row II The third goal can be studied in detail by combined the best design of the PVT system with four types of proposed house under Iraqi weather theoretically by TRANSYS 16 software in term of monthly total energy and daily water consumption the traditional building (without PVT) , integrated with (PVT/water-based) and again with (PVT/Al2O3-water) , (PVT/TiO2-water) and (PVT/Al2O3- TiO2-water) .The results indicated that the annual energy consumption for Models A, B and C1,2,3 are (32.27,18.22, 15.367, 17.88 and 12.75) MWh respectively which means that there is decreasing by about (52.33,44.59 and 60.48) % (52. 33%) and (15.69%) compared with the base case (building without PVT). Furthermore, when using 6wt% of the hybrid nano-fluid (PVT/ Al2O3- TiO2-water), the saving in the collected and auxiliary energy 26.76% and 44.36% in the PVT system, compared with (PVT/Water) system. While in the case of (PVT/Al2O3-water) the saving are: 19.64% and 38.56% and, (PVT/TiO2-water) are: 3.55% and 31.51%. Also, in term of the average stored water temperature, the (PVT/ Al2O3- TiO2-water) reached 55.4℃ while the (PVT/Al2O3-water) and (PVT/TiO2-water) it is reached 48.4℃ and 37.67℃ in a row.So, we concluded that using 6 wt% of the hybrid nanofluid (Al2O3- TiO2-water) show the best performance compared the other. Related to the domestic hot water, the results pointed that the amount of the production of hot water in the winter season covered the demand amount by about (42%) on average. Meanwhile, in the summer season, it covered 100% of the demand Economic results demonstrated that, the annual cost (grid bill) reaches 328.12$, for the proposed house without using the new design of the PVT system while the annual cost will be decreased to 142.29$, which means that by using this PVT system the annual electric bill reduced to 56.63% by saving 185.83$. Finally, the results proved that by using PVT system the annual demand and electricity cost will be decreased and thus, the cut-off electricity problem will be solved particularly with 100% return back of the investment along the PVT system lifetime.
