Experimental and theoretical analysis of mechanical draft counterflow wet cooling towers

Zengin, Görkem; Onat, Ayhan

doi:10.1080/23744731.2020.1822084

Cited by 10 publications

(3 citation statements)

References 4 publications

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“…The condition of the air-vapor mixture at the packing outlet can be specified in terms of the mixture temperature and the humidity ratio. According to the cooling-tower experimental data of Zengin and Onat (2020) and Leeper (1981), the moist air at the outlet of the packing is normally saturated even at a rather low air temperature of 35 o C for cooling tower applications. In the present application, the hot water temperature is much higher, around the level of 100 o C. Because the vapor pressure increases exponentially with temperature and the vapor mass flux intensity at the water-air interface in the packing is at least one order of magnitude higher than that at 35 o C, the saturation condition of the air-vapor mixture should be satisfied.…”

Section: For Power Plant Configuration In Figmentioning

confidence: 99%

Aan Ultimate Solution to Phasing Out Fossil Fuels – Part Ii: Air-Water Thermal Power Plants for Utility-Scale Power Production at Low Temperatures

Cao¹

2022

Front. Heat Mass Transf.

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This paper introduces a novel air-water thermal power plant working at low temperatures and employing hot water as a heat-supply fluid to produce utility-scale power with high second-law efficiency. The air-water power plant uses both air and water as working fluids and employs a direct-contact mass and heat transfer packing to facilitate latent heat (in terms of vapor) and sensible heat transfer from the hot water to moist air for expansion in a gas turbine to produce power. A cycle analysis indicates that with a heat source temperature of around 100 o C, the power plant could achieve a power capacity of more than 300 MW, matching the power capacity of fossil-fuel-based power plants, with a thermal-to-mechanical conversion efficiency above 16%. The power plant could also work in summer involving high temperature/high humidity ambient air by using a chiller to cool the powerplant intake air, the inlet air of the compressor system, or the air in a compressor intercooler. In addition to power production, the power plant could supply hot water for heat or water users. This power plant employs completely clean working fluids of air and water, operates at low temperature and pressure, and can use renewable energy such as solar energy and geothermal energy, as well as heat from other sources including industrial waste heat, to produce utility-scale power with low costs. Combined with hot-water thermal-energy storage systems, the power plant introduced could use renewable energy sources to produce dispatchable power reliably for phasing out most fossil fuels used today and becoming a backbone of national power grids to combat global warming and reduce pollution.

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Section: For Power Plant Configuration In Figmentioning

confidence: 99%

Aan Ultimate Solution to Phasing Out Fossil Fuels – Part Ii: Air-Water Thermal Power Plants for Utility-Scale Power Production at Low Temperatures

Cao¹

2022

Front. Heat Mass Transf.

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“…Currently, thermal performance studies of cooling towers generally focus on freshwater towers and are primarily based on the first law of thermodynamics (energy analysis) [5][6][7][8][9][10], with only a few studies existing on the second law of thermodynamics (exergy analysis), which are also based on freshwater towers. Muangnoi et al [11,12] studied the changes of water exergy, air exergy, and exergy destruction with different height cooling towers.…”

Section: Introductionmentioning

confidence: 99%

Heat and mass transfer performance and exergy performance evaluation of seawater cooling tower considering different inlet parameters

Hou

et al. 2022

THERM SCI

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Cooling towers are important components within recirculating cooling water systems. Due to a shortage of freshwater resources, seawater cooling towers are widely used both in manufacturing and everyday life. This paper researches the mechanical draft counterflow wet seawater cooling tower (MDCWSCT), and establishes and verifies a detailed thermal performance calculation model. Referring to the second law of thermodynamics, the heat and mass transfer performance and exergy performance of the seawater cooling tower were studied. The effects of salinity, inlet air speed, and air wet-bulb temperature on the cooling efficiency, thermal efficiency, and exergy efficiency were analyzed. The results show that compared to the air wet-bulb temperature, changes in air speed have more influence on cooling and thermal efficiency under the study conditions. Moreover, the air wet-bulb temperature is the significant parameter affecting exergy efficiency. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.40-8.25 %, 1.06-3.09 %, and 2.47-7.73 % lower than that of freshwater, respectively, within an air speed of 3.1-3.6 m/s. With an increase in salinity, the cooling, thermal, and exergy efficiency are about 2.28-8.47 %, 1.03-3.37 %, and 2.44-7.99 % lower than that of freshwater, respectively, within an air wet-bulb temperature of 25-27 ?. Through the exergy analysis of the seawater cooling tower, it is obvious that the heat and mass transfer performance and exergy performance can be improved by selecting the optimum operating conditions and appropriate packing specifications.

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“…In addition, the effects of different operating parameters (i.e., the mass flow ratio of air to water, water temperature, air dry‐bulb temperature, and air wet‐bulb temperature, etc.) on heat/mass transfer performance were analyzed experimentally and theoretically by multiple researchers 11–17 . These studies only analyzed one parameter or several parameters, without taking all parameters into account.…”

Section: Introductionmentioning

confidence: 99%

Parametric study of heat/mass transfer performance of seawater–air two‐phase counterflow in packing in seawater cooling towers

Hou

et al. 2022

Heat Trans

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A large amount of waste heat generated in industrial production needs to be discharged by circulating cooling water systems. To save freshwater resources, freshwater cooling towers have been widely replaced by seawater cooling towers in coastal areas, but research on the thermal performance of seawater cooling towers is still relatively less. In this study, a detailed calculation model based on the heat/mass transfer process of seawater-air two-phase counterflow was established, and the reliability of the proposed model was verified. The computer program developed under the VC++ framework was used for the numerical solution of the model. The effects of five inlet parameters on the cooling efficiency and heat dissipation were studied. The simulation resultsshowed that with the increase of salinity, the cooling performance was reduced. When the salinity increased by 10 g/kg, the outlet water temperature rose by about 0.13°C. The wet-bulb temperature increased by 1°C and the cooling efficiency increased by about 0.77%, while total heat dissipation was reduced by about 36.37 kW. When the air-water ratio increased, the cooling performance was improved, but the maximum cooling efficiency was affected by heat load. The change of dry-bulb temperature had little effect on the cooling performance. With the increase of water temperature, the cooling efficiency and heat dissipation increased. The calculation model and simulation results can provide practical guidance for the operation of seawater cooling towers.

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Experimental and theoretical analysis of mechanical draft counterflow wet cooling towers

Cited by 10 publications

References 4 publications

Aan Ultimate Solution to Phasing Out Fossil Fuels – Part Ii: Air-Water Thermal Power Plants for Utility-Scale Power Production at Low Temperatures

Aan Ultimate Solution to Phasing Out Fossil Fuels – Part Ii: Air-Water Thermal Power Plants for Utility-Scale Power Production at Low Temperatures

Heat and mass transfer performance and exergy performance evaluation of seawater cooling tower considering different inlet parameters

Parametric study of heat/mass transfer performance of seawater–air two‐phase counterflow in packing in seawater cooling towers

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