Thermal performance of different pond cells under actual climatic conditions in Qatar

Experimental work was undertaken to study the thermal performance of three different pond cells under actual climatic conditions of Qatar. The first cell was an open pond. In the second unit, a finned radiator, painted black, was placed over the pond. In the third cell, the water was contained in a polyethylene bag. Experimental results indicated that the exposed pond cell came out best, when considered in terms of how quickly the temperature of the stored water could be reduced, and how low that temperature could be. The water in the exposed pond was cooled directly (by evaporation and radiation to sky) whereas in the case of the finned radiator cell, heat had to be transferred from the stored water to the radiator, and then from the radiator to the surrounding. In the case of water-in-bag cell, evaporation was eliminated and radiative exchange with the sky was reduced due to the partial transparency of the polyethylene bag (in the infrared region).     

Validation of CFD simulation for flat plate solar energy collector

The problem of flat plate solar energy collector with water flow is simulated and analyzed using computational fluid dynamics (CFD) software. The considered case includes the CFD modeling of solar irradiation and the modes of mixed convection and radiation heat transfer between tube surface, glass cover, side walls, and insulating base of the collector as well as the mixed convective heat transfer in the circulating water inside the tube and conduction between the base and tube material. The collector performance, after obtaining 3-D temperature distribution over the volume of the body of the collector, was studied with and without circulating water flow. An experimental model was built and experiments were performed to validate the CFD model. The outlet temperature of water is compared with experimental results and there is a good agreement.     

Economics of off-shore/on-shore wind energy systems in Qatar

This work presents an assessment of the potential and economical feasibility of adopting off-shore/on-shore wind energy as a renewable source of energy in Qatar. An analysis is presented for the long term measured on-shore wind speed (1976–2000) at Doha International Airport. A similar analysis is presented for the measured off-shore wind speed at the Qatari Haloul Island. For the on-shore measurements, the average annual wind speed (at 20 m height) was found to be about 5.1 m/s. On the other hand, for the off-shore measurements at Haloul, the average annual wind speed was found to be about 6.0 m/s. This result indicates the suitability of utilizing small to medium-size wind turbine generators, efficiently. Such generators can be implemented for water pumping and to produce sufficient electricity to meet vital, limited needs of remote locations, such as isolated farms, which do not have access to the national electricity grid. An economical assessment is presented which takes into consideration the interest recovery factor, the lifetime of the wind energy conversion system (WECS), the investment rate and operation and maintenance costs. The results indicate that the cost of electricity generation from the wind in Qatar compares favorably to that from fossil fuel resources. The feasibility of utilizing off-shore wind turbine systems to meet the power requirements of the island of Haloul and possibly provide additional power for nearby on-shore areas is discussed.     

Feasibility study of photovoltaic technology in Qatar

This study presents a comparative economic analysis of electricity generation using photovoltaic (PV) cells and conventional gas turbines. The generation cost per kWh was estimated for the two systems. The energy generated by PV cells was estimated using weather data for Qatar. A sensitivity analysis was carried out on some factors: installation capital cost, conversion efficiency and discount rate. The study indicates that, at the present time, PV stations are not economically feasible in Qatar compared with conventional gas turbine stations.