This study involves an experimental and numerical analysis of the Hunter turbine, a vertical axis turbine utilized for tidal energy. A laboratory model of the Hunter turbine, featuring an aspect ratio of 1.2, was designed and tested. Numerical equations, including the Reynolds-averaged Navier–Stokes (RANS) constant, were analyzed through computational fluid dynamics (CFD) software using the k-ω turbulence model to forecast turbine performance and other related flow specifications, such as pressure lines, stream velocity, and pressure. This simulation was conducted on the surface of the turbine blade, and the results were obtained accordingly. The experimental data were utilized to verify the numerical results, and the difference between the two was reasonably acceptable. The turbine was studied in six different flow coefficients and four different vertical positions. The results indicated that the power coefficient increased as the submerged depth from a water-free surface increased, and after a specific depth, the output power remained constant. It was also observed that the minimum depth from a water-free surface for maximum power coefficient was three times the diameter of the turbine drum (3D).

This study concerns with heat and water recovery from the flue gas of a natural gas-fired thermal power plant. A combined system of condensing heat exchanger (CHE) and Organic Rankine Cycle (ORC) is proposed. The CHE acts as the super-heater of the ORC. The flue gas enters to the CHE with a temperature of 160 [Formula: see text] and is cooled to under the water vapor dew point temperature and leads to water vapor condensation, therefore latent and sensible heat are recovered. The condensed water is used as cooling tower make-up water. The ORC refrigerant enters to the CHE as a saturated vapor and is superheated by the recovered heat. In order to achieve the best ORC performance and highest water recovery simultaneously, parametric analysis was done in terms of evaporator and superheating temperature. It was found that by increasing evaporator and superheating temperature, the efficiency and generated power of the ORC increase, although water recovery decreases. Also an increase in evaporator and superheating temperature raises the heat transfer area of CHE, particularly in the non-condensing zone. Therefore to find the optimum evaporation temperature an economic analysis based on NPV method was done and 43°C was determined as the optimum evaporation temperature. Considering this condition, flue gas enters the CHE with a temperature of 160°C and leaves it with a temperature of 57.85°C, and on the other side, the refrigerant enters it in a saturated state and leaves it with a temperature of 75°C. The total area of the CHE is about 39,490 m2. The amount of recovered water is 36.78 kg/s, which saves 34.2 % of the make-up water consumption. Also, the production power of the ORC-CHE was calculated as 24.12 MW and the additional power produced by ORC-CHE compared with bare ORC is 3.97 MW.

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This study concerns a theoretical design of a condensing heat exchanger for a 320 MW unit of Bandar Abbas thermal power plant in the south of Iran. A film theory in conjunction with heat and mass transfer analogy is used as the theoretical basis of the design. The condensing unit is used for heat and mass recovery from the natural gas-fired boiler flue gases. The assumed condensing unit includes 4 equal capacity condensing heat exchangers, each of which is supposed to reduce the flue gas temperature from 160 ℃ to 53℃. Decreasing the flue gas temperature to below the dew point temperature of its water vapor causes condensation (latent) and sensible heat transfer. The analysis was done for 13%, 15%, and 17% of the water vapor volume fraction in the flue gases, and based on the 17% water vapor fraction, 52.8 tons/hr of water was recovered. This recovered water could be used as the cooling tower makeup, and accordingly, almost 14% of water consumption is saved. The recovered heat by the condensing unit is also being used as the heat source of an ORC cycle, and up to 2.8 MW power is estimated to be generated depending on the evaporation temperature.