Cooling Tower Research Articles

An investigation into the efficiency of biocides in controlling algal biofouling in seawater industrial cooling towers

Biofouling in the open recirculating cooling water systems may cause biological corrosion, which can reduce the performance, increase the energy consumption and lower heat exchange resulting in reduced efficiency of the cooling tower (CT). Seawater CTs are prone to bio-fouled due to the presences of organic and inorganic compounds which act as nourishment for various microorganisms like (algae, fungi, and bacteria) for their growth under certain environmental conditions. The most commonly being used method to control the biofouling in CT is by addition of biocides such as chlorination. In this study, diatom and green algae were added to the CT basin and its viability was monitored in the recirculating cooling seawater loop as well as in the CT basin. Three different types of oxidizing biocides, namely chlorine, chlorine dioxide (Chlorine dioxide) and ozone, were tested by continuous addition in pilot-scale seawater CTs and it was operated continuously for 60 d. The results showed that all biocides were effective in keeping the biological growth to the minimum regardless of algal addition. Amongst the biocides, ozone could reduce 99% of total live cells of bacteria and algae, followed by Chlorine dioxide at 97%, while the conventional chlorine showed only 89% reduction in the bioactivities.

Behavioural Study of R C Natural Draught Cooling Towerunder Gravity Load using Different Support Orientations

In the field of both atomic and thermal power-plant the Natural Draught Cooling Tower plays a very important role. The vulnerability of NDCT lies in its hyperbolic shell structure whereas the supporting columns play a pivotal role in load distribution and heat transfer mechanism. Throughout our study effort has been given to find out the behavior of Reinforced Concrete NDCT under static loading using two different types of support orientation. For enhanced accuracy finite element analysis method has been adopted. The geometry of NDCT has been created by strictly following IS code provisions. A detail analysis has been presented in terms of deflection, stress propagation and strain behavior under gravity load. In the final stage a comparison of response behavior of the hyperbolic shell and supporting columns has been prepared with various key components of stress strain behavior.

Assessing the factors affecting the water chemistry parameters in the auxiliary water system of a nuclear power plant

Cooling towers are used as a final heat sink which cools the reactor auxiliary systems and transfers the heat energy to the atmosphere. The reliability endowed upon the cooling tower operation in a nuclear power plant is considerably high when compared to other power plants since the proper functioning of auxiliary systems is crucial for the decay heat removal from the core. Hence, appropriate chemistry control is mandatory in the operation of cooling towers for corrosion control, scale prevention, and control of biological growth. The operating data and water chemistry parameters like conductivity, turbidity, free residual chlorine, pH, cycles of concentration, chlorides, hardness, and alkalinity are analyzed for a typical nuclear power plant. The effect of the individual water quality parameter is correlated by the Pearson matrix to find its influence on the system water chemistry parameter. It is observed that the build-up of chloride ions in the cooling water is the major contributing factor for the cooling tower feed and bleed operations. The aspect of reducing the feed and bleed operation is analyzed, and suitable modifications are suggested to reduce water consumption.

Pengaruh Jumlah Sekat Aliran Lapisan Pengisi Terhadap Unjuk Kerja Menara Pendingin (Cooling Tower)

The cooling tower has a working principle for cool the water fluid forcibly using a fan or blower. This Research aims to determine the effect of the number of filler bulkheads and the angle of openingvalve to the cooling tower work efficiency. This research uses type induced draft cooling tower with flow opposite the tool size laboratory scale. Research variables include 3 variations in the number of bulkheads (2 bulkheads, 3 bulkhead and 4 bulkheads) and 3 variations of valve opening angles (30, 45 and 60). Result measurements in the form of water discharge data, water temperature data, air temperature data, temperature data environment (Twb) and temperature difference data. Water discharge data is measured with a flow meter and stop watch. Temperature data measured with a Digital Thermometer. Data were collected 5 times repetition of each data. The measurement results are taken the average value for measures the discharge, temperature, heat transfer rate and efficiency of the cooling tower. The results showed that the number of bulkheads and the angle of the opening valve has an effect on the working efficiency of Cooling Tower which is getting more the greater the number of bulkheads the greater the cooling tower work efficiency and vice versa but the greater the valve opening angle the smaller the cooling tower efficiency.The maximum efficiency obtained from this study is at the number of bulkheads 4 and the valve opening angle of 30 with a Cooling Tower efficiency value of 78.40%.

An Efficient Cooling Tower for a Stationary Engine

Cooling tower is a type of heat exchanger used to dissipate the unwanted heat from a medium into the atmosphere. A well-designed cooling tower provides prolong contact time for water with air and breaks down the water to have large surface area to promote the heat transfer rate. In the present work, an induced draft cooling tower is fabricated and used with a stationary IC Engine to minimize the overall usage of water. The performance of the tower with two different bed materials (Jute carpet & Polystyrene balls) with and without wire mesh at three different water flow rates viz., 12, 18 and 30 lpm are studied. The cooling tower parameters such as range, approach, efficiency, effectiveness, heat loss, windage losses, and evaporative losses are calculated from the experimental data. At higher flow rates, jute carpets with wire mesh provided optimal results for the parameters while at low flow rates polystyrene balls are found to provide better results. The experimental results showed that the efficiency of the cooling tower increased by 67% as the flow rate increased from 12 lpm to 30 lpm with jute carpet and wire mesh, whereas the efficiency decreases as the flow rate increases with polystyrene as the bed material. Also, the similar trend is observed for the effectiveness of cooling tower.

Reduction of Biofilm Formation on Cooling Tower Heat Exchangers using Nano-silica Coating

Cooling towers are industrial cooling units operating to dissipate heat. As with any surface in contact with aqueous systems, biofilm formation appears on the surface of heat exchangers. Although biofilm formation on plastic tower fill in wet cooling towers has been studied widely, no studies were found regarding biofilm formation on steel heat exchangers in closed-loop systems. In this study, heat exchangers were coated with nano-silica, which is known to reduce the formation of biofilm. Natural biofilm formation was monitored for six months. Biofouling was examined monthly using epifluorescence microscopy by assessing the numbers of live and dead bacteria. It was observed that the biofilm layer formed on the nano-silica coated heat exchanger surfaces was significantly lower than on the control surfaces. 3 log microbial reduction was recorded on coated surfaces in the first month. After six months, total biomass on control surfaces reached 1.28 × 1012 cell cm−2, while the biomass on nano-silica coated surfaces was 6.3 × 104 cell cm−2.

Electrocoagulation for Treatment of Simulated Blowdown Water Of Cooling Tower

This study investigates the results of electrocoagulation (EC) using aluminum (Al) electrodes as anode and stainless steel (grade 316) as a cathode for removing silica, calcium, and magnesium ions from simulated cooling tower blowdown waters. The simulated water contains (50 mg/l silica, 508 mg/l calcium, and 292 mg/l magnesium). The influence of different experimental parameters, such as current density (0.5, 1, and 2 mA/cm2), initial pH(5,7, and 10), the temperature of the simulated solution(250C and 35 0C), and electrolysis time was studied. The highest removal efficiency of 80.183%, 99.21%, and 98.06% for calcium, silica, and magnesium ions, respectively, were obtained at a current density of 1 mA/cm2, initial PH=7, the temperature of 250C and treatment time 60 min. The results have shown the ability of the EC process to remove silica and hardness ions from CTB water.

Prediction of Thermal Performance of Cooling Tower of a Chiller Plant Using Machine Learning

Chiller plants (CP) are accountable for regulating the comfort levels of most indoor environments. The CP uses water as the working medium and acts as a centralized cooling system for the controlled cooling of products, in the different production environments, machine tool industries, 3D printing, packaging, heat exchanging systems and to preserve agricultural produce, dairy products, and other edible items. The CP under study is used for providing cooling to sixteen storeyed hostel building at VIT Chennai. The refrigerant used in this system is Tetra fluoro ethane (R134a). The chilled water (ChW) from the evaporator is circulated to the rooms in the hostel through the secondary circuit and the air handling unit exchanges chillness from the chilled water and finally supplies to the hostel rooms. The chilled water from the hostel returns to the evaporator in a closed loop. The cooling water (CW) from the condenser of the refrigeration system rejects heat to the cooling tower (CT). Thus the performance of the CT is directly linked to the performance of the cooling provided to the hostel rooms. The objective of this research is to predict the temperature at the outlet of the CT integrated with the CP using machine learning algorithms. The predicted values are compared with the measured values and with the values calculated theoretically. The results are analyzed using the standard metrics and are observed to be appreciable.

Determination of the Most Effective Location of Environmental Hardenings in Concrete Cooling Tower Under Far-Source Seismic Using Linear Spectral Dynamic Analysis Results

The feeling of the need to build longer cooling towers increases with the development of the capacity of hydropower plants. So the engineers are trying to design leaner towers, with more buckling resistance using environmental hardening rings. Several studies have investigated the effect of wind strength on these structures, but the effect of seismic acceleration on these structures has been less studied. In this study, by investigating the results of linear spectral dynamic analysis, the optimum location of environmental hardening rings is determined under the influence of earthquake acceleration. The effect of thickness and number of hardening rings on the performance of the tower is also investigated, and the optimum relationship between these two parameters is extracted technically and economically. Different analytical methods can be used to investigate this issue, but using the spectral analysis method besides considering the buckling effects of the tower crust is the most appropriate analytical method for these types of structures.

Data-Driven Digital Twins for Technical Building Services Operation in Factories: A Cooling Tower Case Study

Cyber-physical production systems (CPPS) and digital twins (DT) with a data-driven core enable retrospective analyses of acquired data to achieve a pervasive system understanding and can further support prospective operational management in production systems. Cost pressure and environmental compliances sensitize facility operators for energy and resource efficiency within the whole life cycle while achieving reliability requirements. In manufacturing systems, technical building services (TBS) such as cooling towers (CT) are drivers of resource demands while they fulfil a vital mission to keep the production running. Data-driven approaches, such as data mining (DM), help to support operators in their daily business. Within this paper the development of a data-driven DT for TBS operation is presented and applied on an industrial CT case study located in Germany. It aims to improve system understanding and performance prediction as essentials for a successful operational management. The approach comprises seven consecutive steps in a broadly applicable workflow based on the CRISP-DM paradigm. Step by step, the workflow is explained including a tailored data pre-processing, transformation and aggregation as well as feature selection procedure. The graphical presentation of interim results in portfolio diagrams, heat maps and Sankey diagrams amongst others to enhance the intuitive understanding of the procedure. The comparative evaluation of selected DM algorithms confirms a high prediction accuracy for cooling capacity (R2 = 0.96) by using polynomial regression and electric power demand (R2 = 0.99) by linear regression. The results are evaluated graphically and the transfer into industrial practice is discussed conclusively.

Effects of Material Type on Biofilm Response to an Oxidising Biocide in a Laboratory-Scale Cooling Tower System

Biofilms in industrial cooling tower systems are an important problem. The importance of the surface material in the response to an oxidising biocide (chloramine T trihydrate) was substantiated in our study. Polyvinyl chloride (PVC) cooling tower fill material, stainless steel cooling tower construction material and glass surfaces were compared by evaluating the bacterial loads on materials before and after biocidal treatment. The greatest logarithmic decrease in bacterial load was recorded as >3 log for glass after the first two months and for PVC after the second month. Actively respiring bacterial counts and adenosine triphosphate (ATP) measurements showed that there was no significant difference in the sensitivity of biofilm-associated cells to the biocide on the different surfaces. In addition, the effect of the biocidal treatment decreased with increasing biofilm age, regardless of the material.

Review on: Construction Technique of Hyperbolic Cooling Tower

Review on: Construction Technique of Hyperbolic Cooling Tower

Influence of metal mesh wettability on fog harvesting in industrial cooling towers

Fresh water stress can be alleviated by harvesting water from the fog plumes of industrial cooling towers (CT) using metal meshes. A typical CT fog harvester contains inclined meshes that intercept the rising fog plume. Water droplets deposit on these meshes and then roll down the surfaces due to gravity into a collection manifold below the mesh. The amount of water collected depends on the fraction of fog that is intercepted by the meshes and how the deposited water droplets drain off to the collector. Both fog interception by a mesh and water drainage from it depend on the wettability of the mesh and its inclination with the vertical. Through surface treatments involving either wet chemical etching of stainless steel meshes or electrophoretic deposition of TiO2 nanoparticles on them, we alter mesh wettabilities, making them super-hydrophilic (SHPL), hydrophilic (HPL), or super-hydrophobic (SHPB). Then, fog harvesting efficacy is investigated by placing these meshes in a vertical fog tunnel that resembles a scaled-down configuration of fog collector inside the CT-cell. The drainage from an untreated control mesh and an SHPB mesh are comparable, while SHPL meshes produce poor drainage for small inclinations. Overall, TiO2-coated HPL meshes provide the best drainage which is maximum at a 15° mesh inclination angle.

Performance Enhancement of Induced Draft Counter Flow Wet Cooling Tower with Different Types of Modified Shaped Fill Assembly

This paper presents an experimental analysis of heat transfer using different shaped fills in a counter flow induced draft cooling tower. The main objective is to determine and compare the characteristics of the cooling tower using newly shaped (splash and film) fills and the regular used fills. The newly shaped fills are inverted U-shape cross-sectional splash fill and film fill with ripple plates. The obtained results show that the performance is affected by the type and arrangement of the fills. The modified splash fill has increased the wetted surface area of fill within the same volume compared to regular fills. The film fill with ripple plates has been used such that water from the distribution device ran down on both surfaces of each ripple plate. By the arrangement of ripple plates, cooling loss by premature dropping off of water has been avoided. Performance factors like range, approach, effectiveness, cooling capacity, evaporation loss, percent loss are calculated from collected data for newly shaped fills, and regular shaped fills. It is observed that range, effectiveness, and cooling capacity increases with both newly shaped fills. When ripple plated film fill is used; range, effectiveness, and cooling capacity is found highest among the different shape of fills used in this study. At the same time evaporation loss and percent loss are found lowest for inverted-U shaped splash fill.

Experimental Thermal evaluation of Fluidized Bed Cooling Tower (FBCT) with various Bed elevations and Spherical turbulent balls

Experimental Thermal evaluation of Fluidized Bed Cooling Tower (FBCT) with various Bed elevations and Spherical turbulent balls

Increasing the thermal performance of cooling tower by utilizing swirling jets

Cooling towers are generally utilized in heating, ventilation, and air conditioning systems, electric power plants and manufacturing applications. The main problem for cooling towers is evaporation loss. The evaporation loss is decreased with utilizing fans, drift eliminators for more water saving. This work is mainly focused numerical analysis of cooling tower for reducing evaporation loss and increase the efficiency of the tower by utilizing two crosswise swirling jets that reduce the inlet hot water temperature in the outlet of the cylindrical channel to the not harmful to ambient conditions temperature. The model is computed for various parameters; air inlet temperatures (10, 22, 32, 40 °C) and Reynolds number for jets inlet velocities (Re= 3900, 5200, 7800, 8500). This model was studied numerically by utilizing ANSYS Fluent CFD software. In this work, it is achieved that increasing Reynolds number causes an increase on evaporation loss. The higher air inlet temperature causes higher evaporation loss. When the air inlet temperatures are reduced from 40 °C to 10 °C, the evaporation loss is decreased as 62% and 81%, respectively. When Reynolds number is decreased from 8500 to 3900, the evaporation loss decreased as 30%. By utilizing this new design, the outlet water temperature could be reduced of 19 °C. Moreover, the numerical findings were validated by some researches available in the literature.

Integrated Cooling Tower for Fertilizer Complex a New Approach

Integrated Cooling Tower for Fertilizer Complex a New Approach

Effect of phosphate availability on biofilm formation in cooling towers

Phosphate limitation has been suggested as a preventive method against biofilms. P-limited feed water was studied as a preventive strategy against biofouling in cooling towers (CTs). Three pilot-scale open recirculating CTs were operated in parallel for five weeks. RO permeate was fed to the CTs (1) without supplementation (reference), (2) with supplementation by biodegradable carbon (P-limited) and (3) with supplementation of all nutrients (non-P-limited). The P-limited water contained ≤10 µg PO4 l−1. Investigating the CT-basins and coupons showed that P-limited water (1) did not prevent biofilm formation and (2) resulted in a higher volume of organic matter per unit of active biomass compared with the other CTs. Exposure to external conditions and cycle of concentration were likely factors that allowed a P concentration sufficient to cause extensive biofouling despite being the limiting compound. In conclusion, phosphate limitation in cooling water is not a suitable strategy for CT biofouling control.

Cooling performance of cylinder-frustum natural draft dry cooling tower

Cooling towers are an important part of thermal power plants, and applications of steel cooling towers have increased in recent years. Hyperbolic cooling towers (HCTs) have a traditional geometry. However, this style may be less suitable for steel structures, owing to its construction difficulties. A simpler tower shape is beneficial for constructing steel structures, as it improves construction efficiency and reduces costs. Therefore, the cylinder-frustum cooling tower (CFCT) was selected as the research object in this study. The cooling performance of CFCTs was studied experimentally and by numerical simulations. In the experiment, the particle image velocimetry (PIV) technique was introduced to measure the velocity inside the tower. The results show that the cooling performance of the HCT and that of the CFCT were mostly similar in no-wind conditions. In the numerical simulation, two cooling tower heights were researched to ensure the validity of the results. The influence of geometric parameter p, which is the ratio of frustum height to the shell height, on the cooling performance was studied via computational fluid dynamics (CFD), and recommended geometric parameters were proposed. The recommended value range p for the CFCT is 0.3–0.5.

Comparative analysis between traditional and M-Cycle based cooling tower

The following paper presents the first numerical comparison of heat and mass transfer processes in a traditional cooling tower and a solution based on the Maisotsenko cycle (M-Cycle). The results of the simulation allowed us to analyze the heat and mass transfer process occurring inside the M-Cycle and the traditional cooling tower and to observe its most important characteristics and features. The analysis was performed for two hypothetical situations: 1) both towers having the same external dimensions: the Number of heat Transfer Units (NTU) of M-Cycle cooling tower was two times smaller, due to its geometry; 2) two towers have the same mass transfer surface (i.e. identical NTU in wet channels). It was confirmed that M-Cycle Cooling Tower (MCT) can cool the water below the wet-bulb temperature (which is not achievable by conventional cooling towers), even in very hot and humid conditions (outdoor air temperature of 40 °C and humidity ratio of 20 g/kg). Also, the influence of the selected parameters (including inlet air temperature and humidity, inlet water temperature, NTU, and heat capacity ratio between water and air) on cooling tower performance are documented. Critical factors which have the highest impact on its effectiveness are established and discussed. The study confirmed high practical potential of using M-Cycle in water cooling applications.