Thermal performance analysis of a closed wet cooling tower

2007 ◽  
Vol 221 (3) ◽  
pp. 139-150 ◽  
Author(s):  
V. D. Papaefthimiou ◽  
T. C. Zannis ◽  
E. D. Rogdakis
Keyword(s):  
Thermal Performance ◽  
Cooling Tower ◽  
Water Mass ◽  
Cooling Capacity ◽  
Inlet Temperature ◽  
Water Stream ◽  
Detailed Model ◽  
Air Mass ◽  
Mass Flowrate ◽  
Closed Wet Cooling Tower

A detailed model was developed and employed to examine the thermal performance of a closed wet cooling tower. The model is capable of predicting the variation of air thermodynamic properties, sprayed and serpentine water temperature as well as heat transfer rates exchanged between air and falling water stream inside the indirect wet cooling tower. The reliability of simulations was tested against experimental data obtained from the literature. A parametric study was conducted to evaluate the thermal behaviour of the indirect cooling tower under various air mass flowrates, serpentine water mass flowrates and inlet temperatures. The results of the theoretical investigation revealed an increase in cooling capacity and percentage loss of sprayed water due to evaporation, with increasing air mass flowrate. On the other hand, the increase of serpentine water mass flowrate resulted in slight increase in the overall temperature reduction of serpentine water. The effect of variable serpentine water inlet temperature on thermal performance of the indirect wet cooling tower was insignificant compared to other cases.

scholarly journals On Thermal Performance of Seawater Cooling Towers

2010 ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Governing Equations ◽  
Detailed Model ◽  
Salt Deposition ◽  
Transfer Processes ◽  
Mass Transfer Processes

Seawater cooling towers have been used since the 1970’s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems including salt deposition, packing blockage, corrosion, and certain environmental impacts from salt drift and blowdown return. In addition, the salinity of seawater affects the thermophysical properties which govern the thermal performance of cooling towers, including vapor pressure, density, specific heat, viscosity, thermal conductivity and surface tension. In this paper, the thermal performance of seawater cooling towers is investigated using a detailed model of a counterflow wet cooling tower. The model takes into consideration the coupled heat and mass transfer processes and does not make any of the conventional Merkel approximations. In addition, the model incorporates the most up-to-date seawater properties in the literature. The model governing equations are solved numerically and its validity is checked by data in the literature. Based on the results of the model, a correction factor is obtained which characterizes the degradation of the cooling tower effectiveness when seawater is used.

Experimental Investigation of a Pilot Compression Chiller With Alternatives Refrigerants R401a and R134a

2005 ◽  
Author(s):  
M. Fatouh
Keyword(s):  
Experimental Investigation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Mass ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Inlet Temperature ◽  
Chilled Water ◽  
Water Mass Flow Rate

This paper reports the results of an experimental investigation on a pilot compression chiller (4 kW cooling capacity) working with R401a and R134a as R12 alternatives. Experiments are conducted on a single-stage vapor compression refrigeration system using water as a secondary working fluid through both evaporator and condenser. Influences of cooling water mass flow rate (170–1900 kg/h), cooling water inlet temperature (27–43°C) and chilled water mass flow rate (240–1150 kg/h) on performance characteristics of chillers are evaluated for R401a, R134a and R12. Increasing cooling water mass flow rate or decreasing its inlet temperature causes the operating pressures and electric input power to reduce while the cooling capacity and coefficient of performance (COP) to increase. Pressure ratio is inversely proportional while actual loads and COP are directly proportional to chilled water mass flow rate. The effect of cooling water inlet temperature, on the system performance, is more significant than the effects of cooling and chilled water mass flow rates. Comparison between R12, R134a and R401a under identical operating conditions revealed that R401a can be used as a drop-in refrigerant to replace R12 in water-cooled chillers.

scholarly journals On Thermal Performance of Seawater Cooling Towers

2010 ◽  
Vol 133 (4) ◽  
Author(s):  
Mostafa H. Sharqawy ◽  
John H. Lienhard ◽  
Syed M. Zubair
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Cooling Tower ◽  
Cooling Towers ◽  
Governing Equations ◽  
Detailed Model ◽  
Salt Deposition ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Seawater Salinity

Seawater cooling towers have been used since the 1970s in power generation and other industries, so as to reduce the consumption of freshwater. The salts in seawater are known to create a number of operational problems, including salt deposition, packing blockage, corrosion, and certain environmental impacts from salt drift and blowdown return. In addition, the salinity of seawater affects the thermophysical properties that govern the thermal performance of cooling towers, including vapor pressure, density, specific heat, viscosity, thermal conductivity, and surface tension. In this paper, the thermal performance of seawater cooling towers is investigated using a detailed model of a counterflow wet cooling tower. The model takes into consideration the coupled heat and mass transfer processes and does not make any of the conventional Merkel approximations. In addition, the model incorporates the most up-to-date seawater properties in the literature. The model governing equations are solved numerically, and its validity is checked against the available data in the literature. Based on the results of the model, a correction factor that characterizes the degradation of the cooling tower effectiveness as a function of seawater salinity and temperature approach is presented for performance evaluation purposes.

Experimental Research on the Effect of Cross-Wind to Wet-Cooling Tower Performance

2013 ◽  
Vol 860-863 ◽  
pp. 1412-1415
Author(s):  
Qing Yang Wang ◽  
Tian Yu Sun ◽  
Jian Zhang ◽  
Jian Xing Ren
Keyword(s):  
Wind Velocity ◽  
Flow Rate ◽  
Temperature Difference ◽  
Cooling Tower ◽  
Thermal Power ◽  
Water System ◽  
Cooling Water ◽  
Cooling Capacity ◽  
Inlet Temperature ◽  
Circulating Water

Environmental cross-wind has a influence on cooling capacity of wet cooling tower to a great extent in power plant.The variation of circulating-water temperature difference (Δt) and cooling coefficient of efficiency(η) with cross-wind velocity, circulating water inlet temperature and flow rate, are shown under cross-wind conditions, compared with cases without wind. By using experimental platform of cooling water system based on 300MW thermal power unit,it is found that with cross-wind velocity increasing,cooling temperature difference and cooling efficiency decrease first then increase at the knee point when the velocity value is 0.8m/s. In addition, the correlation betweenΔt ,η and parameters,such as circulating-water inlet temperature and flow rate, is derived for cases with windless conditions.

Thermal performance of a closed wet cooling tower for chilled ceilings: measurement and CFD simulation

2000 ◽  
Vol 24 (13) ◽  
pp. 1171-1179 ◽  
Author(s):  
Saffa Riffat ◽  
Armando Oliveira ◽  
Jorge Fac�o ◽  
Guohui Gan ◽  
Prince Doherty
Keyword(s):  
Thermal Performance ◽  
Cooling Tower ◽  
Cfd Simulation ◽  
Closed Wet Cooling Tower
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