Performance of a Cooling Tower with the Use of a New Kind of High-density Polyethylene (HDPE) Packing

This research work deals with the performance of high-density polyethylene sheets arranged in splash used as a fill for a cooling tower. “A forced-draught counter flow cooling tower” of 400 mm × 400 mm cross-sectional area and 1.7m in height was built. The fill has been studied theoretically and experimentally. Air rates of 0.6, 1.2, and 1.8 kg/s.m2 were utilized with water flow rates within the range of 1 to 1.6 kg/s.m2. The overall volumetric heat transfer coefficient, volumetric mass transfer coefficient (Mt), and the tower characteristics (Mt/L) are shown to be functions of the air and water flow rates concurrently. Four available input parameters were inlet water temperature, airflow rate, water flow rate, and full height. A computer program was prepared to perform numerical analysis for reducing data sets obtained from the plant. In addition, analysis was carried out for evaluating the volumetric heat and mass transfer coefficients along with the performance coefficient.

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Experimental Evaluation of Optimum Water to Air Flow Ratio in an Induced Draft Wet Cooling Tower

FUOYE Journal of Engineering and Technology ◽

10.46792/fuoyejet.v4i2.331 ◽

2019 ◽

Vol 4 (2) ◽

Author(s):

Talib O Ahmadu ◽

Hamisu A Dandajeh

Keyword(s):

Water Flow ◽

Flow Rate ◽

Cooling Tower ◽

Air Flow ◽

Water Flow Rate ◽

Cooling Power ◽

Cooling Efficiency ◽

Flow Ratio ◽

Flow Rates ◽

Optimum Water

Cooling towers are devices used to dissipate waste thermal heat to the ambient environment. Appropriate cooling water and air flow rates are necessary to ensure optimum cooling power and cooling efficiency. Also, a simple design is required for cost effectiveness and minimal maintenance issues. This paper experimentally evaluates the cooling power, cooling efficiency, as well as the optimum water to air flow ratio in a spray type induced draft wet cooling tower. The cooling tower, 6 kW cooling capacity, was developed to operate without packings. The experiments were conducted for three different air flow rates and six different water flow rates. Four different inlet water temperatures of 35, 40, 45 and 50 oC were used. The temperature range is a typical range for inlet water temperature to the cooling tower for an absorption cooling system. For each of the inlet water temperatures, air and water flow rates were varied. The effects of this variation on cooling power and cooling efficiency were studied. Effect of varying water to air flow ratio on cooling power and cooling efficiency were studied. Results showed that the cooling power increased with increasing water flow rate, while the cooling efficiency decreased with increasing water flow rate. Decreasing the air flow rate was seen to cause a decrease in both cooling power and cooling efficiency. Maximum cooling power and cooling efficiency of 5.33 kW and 63% respectively were obtained. An optimum water to air flow ratio of 1.6 was obtained. The cooling tower was seen to have operated satisfactorily without packings. Keywords— cooling tower, cooling power, cooling efficiency, flow ratio, thermal energy

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Experimental Investigation on Improvement of Wet Cooling Tower Efficiency with Diverse Packing Compaction Using ANN-PSO Algorithm

Energies ◽

10.3390/en14010167 ◽

2020 ◽

Vol 14 (1) ◽

pp. 167

Author(s):

Hasan Alimoradi ◽

Madjid Soltani ◽

Pooriya Shahali ◽

Farshad Moradi Kashkooli ◽

Razieh Larizadeh ◽

...

Keyword(s):

Neural Network ◽

Water Temperature ◽

Water Flow ◽

Flow Rate ◽

Cooling Tower ◽

Air Flow ◽

Water Flow Rate ◽

Pso Algorithm ◽

Outlet Temperature ◽

Air Flow Rate

In this study, a numerical and empirical scheme for increasing cooling tower performance is developed by combining the particle swarm optimization (PSO) algorithm with a neural network and considering the packing’s compaction as an effective factor for higher accuracies. An experimental setup is used to analyze the effects of packing compaction on the performance. The neural network is optimized by the PSO algorithm in order to predict the precise temperature difference, efficiency, and outlet temperature, which are functions of air flow rate, water flow rate, inlet water temperature, inlet air temperature, inlet air relative humidity, and packing compaction. The effects of water flow rate, air flow rate, inlet water temperature, and packing compaction on the performance are examined. A new empirical model for the cooling tower performance and efficiency is also developed. Finally, the optimized performance conditions of the cooling tower are obtained by the presented correlations. The results reveal that cooling tower efficiency is increased by increasing the air flow rate, water flow rate, and packing compaction.

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The Influence of Optic and Polarographic Dissolved Oxygen Sensors Estimating the Volumetric Oxygen Mass Transfer Coefficient (KLa)

Modern Applied Science ◽

10.5539/mas.v10n8p142 ◽

2016 ◽

Vol 10 (8) ◽

pp. 142 ◽

Cited By ~ 1

Author(s):

Gustavo Andrés Baquero-Rodríguez ◽

Jaime A. Lara-Borrero

Keyword(s):

Mass Transfer ◽

Wastewater Treatment ◽

Dissolved Oxygen ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Oxygen Transfer ◽

Airflow Rate ◽

Oxygen Probe ◽

Aeration System ◽

Oxygen Measurement

Aeration is usually the most energy intensive part of the wastewater treatment process. Optimizing the aeration system is essential for reducing energy costs. Field tests oriented to estimate parameters related to oxygen transfer are a common approach to compare aeration systems. The aim of this research is to assess the effect of dissolved oxygen probe lag on oxygen transfer parameter estimation. Experimental procedures regarding to process automation and control were applied to quantify dissolved oxygen probe lag. We have measured oxygen transfer in clean water, under a wide range of conditions (airflow rate, diffuser characteristics and diffuser density), with optic and polarographic sensors for dissolved oxygen measurement. The oxygen transfer was measured as per ASCE Standard procedures. Nonparametric statistical tests were used to compare the estimated volumetric mass transfer coefficient KLa with different sensors. According to the results, there is not significant influence of the probe lag (also known as time constant) or probe characteristics on the parameters used to assess oxygen transfer efficiency. This fact has great relevance in common practice of aerobic process for wastewater treatment because dissolved oxygen monitoring is used as an input for decision making related to the energy optimization in the aeration system. Findings from these tests contradict previous studies which claim that lag time in polarographic sensors for the dissolved oxygen measurement can bias estimate KLa.

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A Method for Calculating the Unsaturated Humid Air Flow Section Length in the Mechanical Draft Cooling Tower Sprinkler Channel

Vestnik MEI ◽

10.24160/1993-6982-2021-4-37-43 ◽

2021 ◽

pp. 37-43

Author(s):

Vasiliy Ya. Gubarev ◽

◽

Aleksey G. Arzamastsev ◽

Aleksey I. Sharapov ◽

Yuliya O. Moreva ◽

...

Keyword(s):

Mass Transfer ◽

Air Temperature ◽

Flow Rate ◽

Cooling Tower ◽

Initial Conditions ◽

Air Flow ◽

Water Flow Rate ◽

Flow Section ◽

Transfer Coefficients ◽

Humid Air

In the channels of mechanical-draft cooling tower sprinklers, a saturated air flow section may appear under certain initial conditions, the mass transfer intensity in which is limited by the steam content in the saturated air. For correctly calculating the heat and mass transfer processes in the cooling tower channel, it is necessary to have a method for determining the unsaturated air flow section length. Publications devoted to studying water cooling processes in the channels of mechanical-draft cooling tower sprinklers do not contain an assessment of the unsaturated air flow section length. A method for determining the unsaturated humid air flow section length in the mechanical-draft cooling tower sprinkler channels is proposed, which is based on the well-known criterion equations for calculating the heat transfer and mass transfer coefficients. The effect the initial air parameters have on the unsaturated air section length is studied, and graphic dependences of the unsaturated air section length are drawn up for each of the analyzed parameters. It is shown that the unsaturated humid air flow section length increases with increasing the initial air temperature. It is also found that the unsaturated air flow section length decreases with a growth in the relative air humidity. An increase in the air flow rate with a constant water flow rate leads to an increase in the unsaturated air flow section length. For the considered sprinkler channel, the saturated air region exists at an air temperature of 15°C and below, and for air temperatures above 25°C there is no saturated air flow section. It is shown that the conclusions drawn about the effect the initial air parameters have on the relative change in the unsaturated air flow section length are valid for channels of various shapes and geometric sizes. The proposed methodology and the results obtained can be used in designing mechanical-draft cooling towers and estimating their efficiency.

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Using a Novel Phase Change Material-Based Cooling Tower for a Photovoltaic Module Cooling

Journal of Solar Energy Engineering ◽

10.1115/1.4044890 ◽

2019 ◽

Vol 142 (2) ◽

Cited By ~ 1

Author(s):

Nasrin Abdollahi ◽

Masoud Rahimi

Keyword(s):

Surface Temperature ◽

Phase Change ◽

Phase Change Material ◽

Output Power ◽

Water Flow ◽

Flow Rate ◽

Cooling Tower ◽

Water Flow Rate ◽

Helical Tube ◽

Change Material

Abstract This paper presents an experimental investigation on a hybrid solar system, including a water-based photovoltaic (PV) solar module and a phase change material (PCM)-based cooling tower, for cooling of the module. Elimination of heat from the PV module was performed by the use of water in the back of the panel. The PCM-based cooling tower was used as a postcooling system. A composite oil consisting of 82 wt% coconut oil and 18 wt% sunflower oil has been used as a novel phase change material in the cooling tower. The helical tubes of the cooling tower were fabricated in two different curvature ratios of 0.054 and 0.032. The experiments were performed at three different water flow rates of 11.71, 16.13, and 19.23 mL/s. The cooling performance evaluation was carried out using the average surface temperature and output power of the photovoltaic panel. The results indicated that diminution of the average PV surface temperature relative to the reference temperature was 34.01 and 32.36 °C at a water flow rate of 19.23 mL/s for the cooling systems with helical tube curvature ratios 0.054 and 0.032, respectively. Furthermore, the highest electric output power was achieved for the cooling system with a helical tube curvature ratio of 0.054 at a water flow rate of 19.23 mL/s.

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Performance of the volumetric mass transfer coefficient in a cooling tower

Contemporary Engineering Sciences ◽

10.12988/ces.2018.84202 ◽

2018 ◽

Vol 11 (41) ◽

pp. 1999-2006

Author(s):

Jorge Duarte Forero ◽

Guillermo Valencia Ochoa ◽

Luis Obregon Quinones

Keyword(s):

Mass Transfer ◽

Transfer Coefficient ◽

Mass Transfer Coefficient ◽

Cooling Tower ◽

Volumetric Mass Transfer Coefficient

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Analysis of Fouling Characteristic in Enhanced Tubes Using Multiple Analogies

2010 14th International Heat Transfer Conference, Volume 4 ◽

10.1115/ihtc14-22529 ◽

2010 ◽

Cited By ~ 1

Author(s):

Wei Li ◽

Guanqiu Li ◽

Zhengjiang Zhang ◽

Zhiming Xu ◽

Shanrang Yang

Keyword(s):

Mathematical Model ◽

Mass Transfer ◽

Heat Flux ◽

Transfer Coefficient ◽

Cooling Tower ◽

Comprehensive Analysis ◽

Von Karman ◽

Enhanced Tubes ◽

Plain Tube ◽

Von Kármán

This paper provides a comprehensive analysis on cooling tower fouling data taken from seven 15.54 mm I.D. helically ribbed, copper tubes and a plain tube at Re = 16000. A new mathematical model has been developed. The mass transfer coefficient Km is calculated through three analogies, which are Prandtl analogy, Von-Karman analogy, and j factor analogy. Fouling deposition is assumed to be determined by two processes, which are corresponding to heat flux and fluid friction. Von-Karman analogy is proved the best analogy among the three. Series of semi-theoretical fouling correlations as a function of the product of area indexes and efficiency indexes were developed. They were applicable to different internally ribbed geometries. The correlations can be directly used to assess the fouling potential of enhanced tubes in actual cooling tower water situations.

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Effects of Water Flow Rate on Fatigue Life of Carbon Steel in Simulated LWR Environment Under Low Strain Rate Conditions

Journal of Pressure Vessel Technology ◽

10.1115/1.1460906 ◽

2003 ◽

Vol 125 (1) ◽

pp. 52-58 ◽

Cited By ~ 3

Author(s):

Akihiko Hirano ◽

Michiyoshi Yamamoto ◽

Katsumi Sakaguchi ◽

Tetsuo Shoji ◽

Kunihiro Iida

Keyword(s):

Fatigue Life ◽

Carbon Steel ◽

Strain Rate ◽

Water Flow ◽

Flow Rate ◽

Water Flow Rate ◽

Flow Rates ◽

Life Evaluation ◽

Significant Difference ◽

Fatigue Life Evaluation

The flow rate of water flowing on a steel surface is considered to be one of the important factors strongly influencing the fatigue life of the steel, because the water flow produces difference in the local environmental conditions. The effect of the water flow rate on the fatigue life of a carbon steel was thus investigated experimentally. Fatigue testing of the carbon steel was performed at 289°C for various dissolved oxygen contents (DO) of less than 0.01 and 0.05, 0.2, and 1 ppm, and at various water flow rates. Three different strain rates of 0.4, 0.01, and 0.001 %/s were used in the fatigue tests. At the strain rate of 0.4 %/s, no significant difference in fatigue life was observed under the various flow rate conditions. On the other hand, at 0.01 %/s, the fatigue life increased with increasing water flow rate under all DO conditions, such that the fatigue life at a 7 m/s flow rate was about three times longer than that at a 0.3 m/s flow rate. This increase in fatigue life is attributed to increases in the crack initiation life and small-crack propagation life. The major mechanism producing these increases is considered to be the flushing effect on locally corrosive environments at the surface of the metal and in the cracks. At the strain rate of 0.001 %/s, the environmental effect seems to be diminished at flow rates higher than 0.1 m/s. This behavior does not seem to be explained by the flushing effect alone. Based on this experimental evidence, it was concluded that the existing fatigue data obtained for carbon steel under stagnant or relatively low flow rate conditions may provide a conservative basis for fatigue life evaluation. This approach seems useful for characterizing fatigue life evaluation by expressing increasing fatigue life in terms of increasing water flow rate.

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Performance Analysis of a Desiccant Evaporative Cooling System for Mango Fruit Storage in the Savannah and Transitional Zones of Ghana

Agricultural Engineering ◽

10.1515/agriceng-2019-0021 ◽

2019 ◽

Vol 23 (3) ◽

pp. 1-14

Author(s):

Awafo Edward ◽

Addo Ahmad ◽

Bart-Plange Ato

Keyword(s):

Performance Analysis ◽

Water Flow ◽

Cooling System ◽

Evaporative Cooling ◽

Airflow Rate ◽

Fruit Storage ◽

Flow Rates ◽

Evaporative Cooling System ◽

Line Slope ◽

Best Fit

AbstractPerformance analysis of a 1.0 tonne desiccant evaporative cooling storage structure for mango fruits was studied. The study examined the effects of inlet air conditions and water flow rates through an absorber on the cooling performance of the system. The airflow rate was approximately 0.24 m3·s−1 and water flow rates through the absorber varied from 0 to 0.252 l·s−1. The system produced approximately 7 kW of cooling at water supply rate of 0.252 l·s−1. A simple linear correlation was established for condition line slope from inlet to exiting air conditions for all the water flow rates. Lines of best fit resulted in correlation coefficient better than 0.96. The observed temperatures with a direct evaporative cooler, tested with freshly harvested mango fruits were found to be between 15.1°C and 23.4°C and relative humidity between 81.8% and 97.7%. Physiological weight loss and firmness assessments of the fruits were also conducted.

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