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In this paper, a neuro-adaptive PI control strategy for a water-cooled centrifugal chiller system is developed, and its control performance is examined. The system model consists of a flooded evaporator, a flooded condenser, a centrifugal compressor, and an electronic expansion valve. The overall system consists of three control loops: a compressor speed control loop, an inlet guide vane (IGV) control loop, and a condenser liquid level control loop. A neuro-adaptive control strategy for compressor speed control was designed. The control performance of the chiller was tested by carrying out simulation runs using an integrated building and HVAC (IB-HVAC) system model. The major details of the IB-HVAC model are described in this paper. Results show that the neuro-adaptive controller can adapt to new system dynamics of the IB-HVAC system and give good setpoint tracking responses under a wide range of operating conditions. The results show that the neuro-adaptive controller performs better than the constant gain PI controller in terms of speed of response and setpoint tracking properties. [ABSTRACT FROM AUTHOR]

The Behavior of Cement Portland Cooling Tower was evaluated numerically and experimentally. The three-dimensional simultaneous governing equations of the fluid flow, heat transfer and mass transfer were discretized and solved numerically, and the result of simulation were compared with measured data from the cement factory and with the available published result on the internet. Solid software was used as numerical software tool to predict the performance characteristics of cooling tower in Portland cement factory such as the velocity, temperature, stress and strain were simulated and compared with compute experiment. Experimentally the temperature, and pressure of gaseous and its emission across the cooling tower in White Portland cement factory were measured. The agreement seems acceptable between the numerical and experimental results. [ABSTRACT FROM AUTHOR]

This research examines the water and energy performance in wet cooling towers and identifies methods for enhancing efficiency and minimizing water and energy consumption by exploring methods to enhance system performance. A three-dimensional transient model, developed using MATLAB's open-source code software, was utilized to simulate the cooling tower's behaviour under various operating conditions. This research focuses on precise simulation of cooling tower behavior and demand modeling aided by regression. The model's accuracy was validated through experimental measurements in diverse environmental conditions. The key parameter and performance that is investigated in this paper is the temperature profile of the cooling tower, in which the performance algorithm and proposed methodologies are anchored in the operational temperature. The experimental results led to operational solutions for enhancing cooling tower performance. For winter conditions, the recommended action involves closing the upper part of the cooling tower and activating the two side fans. Specific approaches are suggested for mid-season and summer scenarios, focusing on make-up water consumption and ambient air temperature control, respectively. In addition, results indicated a close alignment between the model and the actual system, with discrepancies of less than 2% in energy consumption and 5% in water consumption. Analysis of proposed productivity enhancements and changes in supply policies indicated significant potential for energy and water conservation in wet cooling towers. Implementing these solutions could lead to an estimated annual reduction of 44% in water consumption and 4.2% in energy consumption. [ABSTRACT FROM AUTHOR]

Cooling towers, by producing chilled water and by integration with radiant and displacement cooling systems, offer a possible alternative method for space conditioning of office buildings in temperate climates. This present study examines the operational feasibility of a cooling tower in conjunction with a radiant and displacement ventilation cooling system for office conditioning in four temperate climates. The climates are: cool and semi-humid (Birmingham, UK), cool and dry (Helsinki, FI), warm and humid (Paris, FR) and warm and dry (Prague, CZ). The system is capable of producing chilled water between 14 and 20 °C, with low approach tower temperatures (1–3 K). A mathematical model of the cooling tower system was developed and integrated with an office building energy simulation model. Using the integrated simulation model, assessment was carried out based on ASHRAE design day specifications, as well as a complete cooling seasonal analysis. Moreover, the performance of the system is benchmarked against a variable-air-volume cooling system. Energy savings for the system when benchmarked against a variable-air-volume air conditioning system, where the chiller COP (coefficient of performance) varies from 2.75 to 6.5, were 62% to 37% in Paris, 56% to 30% in Prague, 52% to 28% in Helsinki and 45% to 13% in Birmingham, respectively. [ABSTRACT FROM AUTHOR]

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The current research aims at finding a new appropriate way to optimize and reduce water consumption by using various forms of pinch technology in petrochemical complexes due to high rate of water consumption. For this purpose, precise studies were conducted on ethylene plant. In this research, cracked gas compressor (CGC) system was considered to analyze energy and minimize water consumption of heat exchanger network (HEN). Initially, process of the CGC system has been simulated with Aspen HYSYS. Next, Aspen Energy Analyzer software was used to identify cooling water (CW) heat exchangers and economic analysis of HEN. Consequently, composite curves and grand composite curves and other results of HEN simulation were examined. The results of HEN simulation indicate that 91% of cooling loads provided by CW utility is the most widely used fresh water. Despite water circulation system of cooling tower (CT), the rate of water loss is high in this utility. As the design temperature is 40 °C and the minimum approach temperature (ΔTmin) is 10 °C, the new utility pinch point has been estimated 50 °C. In proposed modified case, air coolers were considered before the CW heat exchangers of the CGC system. In this way, air-cooled (AC) utility covers up cooling loads up to 50 °C in the modified unit. Then, the modified unit was compared with main unit. In the modified unit, 78% of cooling loads of the HEN have been covered by AC utility in which this action leads to 86% reduction in energy and water consumption of CW heat exchangers and CT. By reducing the rate of water loss in CT circulation systems, cost of supplying fresh water reduced to the lowest possible which leads to 34% optimization in HEN operating cost in the modified unit. Also in the CGC system, steam turbine is used for supplying power consumption of compressor used to CW steam turbine condenser. This condenser is the most commonly used equipment in terms of water consumption, so that there is 32% more than the total water consumption of the HEN. In the last part of this study, AC steam turbine condenser replaced the CW steam turbine condenser in the modified case. So in this case, the use of AC steam turbine condenser with power consumption (980 kw) leads to 98% reduction in water consumption of the steam turbine condenser. [ABSTRACT FROM AUTHOR]

The object of research is the process of cooling mineral fertilizer granules in a granulation tower. The main problem that was solved was the analysis of the temperature mode of cooling the granules to increase their strength and quality, as well as to reduce the probability of their destruction during storage and transportation. The design of a rotating vibrating granulator (RVG) and a mathematical model for calculating the temperature of granules and air at different stages of the granulation process are presented. Reynolds, Peclet and Prandtl criteria are used to describe hydrodynamic and thermodynamic processes. In the course of the work, a calculation model and the possibility of predicting the final temperature of mineral fertilizer granules were created, which allows to avoid negative consequences, such as a decrease in the strength of the granules and their destruction during shipment, transportation and introduction into the soil. Improving the technological performance of the granulation tower, in particular the temperature regimes of granule cooling, contributes to the improvement of product quality. The calculation model allows to adjust the process parameters to ensure the formation of granules with specified properties that meet modern requirements for the monodisperse composition of mineral fertilizer granules. Results were obtained that show the influence of hydrodynamic and thermodynamic factors on the process of cooling and crystallization of granules. This is due to the use of a rotating vibrating granulator, which ensures uniform distribution of liquid droplets across the cross section of the tower and their effective cooling due to contact with the air flow. The results can be used in practice to improve the operation of granulation towers in the production of mineral fertilizers, which allows to improve the quality of products and improve their storage and use. Compared to similar methods, the use of the proposed models provides increased strength and uniformity of granules, which are key advantages in conditions of large-scale production of fertilizers. [ABSTRACT FROM AUTHOR]

A hybrid cooling tower, which is a promising type of coolers, can be used successfully to cool the circulating water of industrial enterprises taking into account the modern requirements for energy efficiency, resource saving, and environmental friendliness. A hybrid cooling tower design has been developed including a sprinkler made of inclined corrugated contact elements and an internal finned tubular radiator. The purpose of the work is to experimentally determine the volumetric coefficients of heat and mass emission in the developed hybrid cooling tower for cooling circulating water. A diagram of an experimental installation of a cooling tower with hybrid cooling system is presented and described. Graphic dependences were constructed for the volumetric coefficients of mass emission and heat emission on the average flow rate of cooling air at various wetting mass densities. A dimensionless equation has been obtained for determining the volumetric coefficients of mass emission in a hybrid cooling tower with transverse finning of radiator pipes. A comparison of volumetric coefficients of mass emission for the developed cooling tower with other water-cooling devices showed the potential of its usage for cooling circulating water, especially at high ratios of gas and liquid phase loads. [ABSTRACT FROM AUTHOR]

Wastewater treatment and simultaneous production of value-added products with microalgae represent a sustainable alternative. Industrial wastewater, characterized by high C/N molar ratios, can naturally improve the carbohydrate content in microalgae without the need for any external source of carbon while degrading the organic matter, macro-nutrients, and micro-nutrients. This study aimed to understand the treatment, reuse, and valorization mechanisms of real cooling tower wastewater (CWW) from a cement-processing industry mixed with domestic wastewater (DW) to produce microalgal biomass with potential for synthesis of biofuels or other value-added products. For this purpose, three photobioreactors with different hydraulic retention times (HRT) were inoculated simultaneously using the CWW-DW mixture. Macro- and micro-nutrient consumption and accumulation, organic matter removal, algae growth, and carbohydrate content were monitored for 55 days. High COD (> 80%) and macronutrient removals (> 80% of N and P) were achieved in all the photoreactors, with heavy metals below the limits established by local standards. The best results showed maximum algal growth of 1.02 g SSV L−1 and 54% carbohydrate accumulation with a C/N ratio of 31.24 mol mol−1. Additionally, the harvested biomass presented a high Ca and Si content, ranging from 11 to 26% and 2 to 4%, respectively. Remarkably, big flocs were produced during microalgae growth, which enhanced natural settling for easy biomass harvesting. Overall, this process represents a sustainable alternative for CWW treatment and valorization, as well as a green tool for generating carbohydrate-rich biomass with the potential to produce biofuels and fertilizers. [ABSTRACT FROM AUTHOR]

Gas conditioning towers (GCTs) or cooling towers have broad industrial applicability, especially in the cement industry. Most cement factories deal with the same problems faced by other factories. However, the solutions to these problems are barely internationally published and have not received much attention, meaning a lot of time and money is spent on researching previous solutions. Iran is among the top ten cement manufacturing countries in the world. Therefore, many of these problems have occurred in Iranian cement factories. The purpose of this paper is to provide a review of studies in this field over the last couple of decades, with a particular focus on advances in Iran. The most important findings in the literature are summarised in order to suggest the best possible solutions for improving the performance and lifetime of GCTs and decreasing common problems such as dust build-up and wet bottom. Numerical methods for modelling different aspects of GCTs are reviewed. The results can be used to reduce water and energy consumption, air pollution and the repair and maintenance costs of cement factories. [ABSTRACT FROM AUTHOR]

The condensation heat exchanger has a critical role in the microwave reduction process to separate and capture valuable by‐products after the microwave reactor. This study aims to perform a computational fluid dynamics (CFD) simulation of a condenser to assess the heat transfer performance of the heat exchanger comprehensively. The type of heat exchanger used for this study is based upon an existing industrial‐scale condenser taken from a conventional thermal pyrolysis end of tires (ELT) reprocessing plant and repurposed for integration into a 1500 kg/h ELT microwave reduction process. The condenser is a shell‐and‐multiple‐tube heat exchanger in which the syngas passes through the tubes while cold water from a cooling tower is placed inside the shell. After the simulation, the effects of inlet temperatures and mass flow rates of the gas and water are investigated. The results show that the heat transfer rate is 58 kW for the inlet air velocity of 0.25 m/s and increases due to the convective heat transfer by 32% and 55% when the air velocity rises to 0.5 and 1 m/s, respectively, for the inlet gas and water temperatures of 80 and 15°C, respectively. Additionally, because the outlet air temperature and the inlet water temperature are strongly correlated with convective heat transfer, the outlet air temperature is equivalent to 17.2, 22.3, and 29.5°C when the inlet water temperature is 15, 20, and 25°C, respectively. [ABSTRACT FROM AUTHOR]

When heating units are operated in winter, the extreme conditions, such as deep peak regulation and large extraction, can easily lead to a low unit load and severe icing in the wet cooling tower, which threatens the safe operation of the unit. Therefore, it is necessary to study the anti-freezing characteristics of the wet cooling tower. In this paper, a three-dimensional numerical model of a high-level, natural draft wet cooling tower is developed based on the constant heat load method. The influence of withdrawing a certain percentage of circulating water into the bypass on the cooling performance and anti-freezing characteristics of the high-level, natural draft wet cooling tower is investigated. The results show that as the percentage of circulating water bypass extraction increases, the temperature drop of circulating water in the tower continues to increase, but the lowest and the average water temperatures at the bottom of the packing continue to decrease. At the same time, the amount of circulating water entering the tower decreases, the pressure difference between the inside and outside of the tower under the same environmental conditions decreases, and the pumping force of the cooling tower decreases. If the circulating water bypass extraction percentage is less than 10%, it can prevent the circulating water from freezing at the bottom of the packing and, at the same time, try to reduce the temperature of the circulating water entering the condenser to ensure the efficiency of the unit. [ABSTRACT FROM AUTHOR]

The number of XLPE cables being used near or beyond their design life is increasing. The importance of timely cable replacement is necessary. Therefore, research is actively being conducted using VLF Tan δ diagnostic technology to assess the insulation condition of cables. Present studies lack in measuring and analyzing the VLF Tan δ of service-aged XLPE cables. Additionally, there is a research gap considering the operating environment. Therefore, it is needed to diagnose and analyze the insulation condition of the same service-aged cable when it is operated in a different environment. This paper assesses and analyzes the insulation condition of cables installed in the BFP, cooling tower, and deaerator booster pump of a combined heat and power plant. Each cable was evaluated by measuring the VLF Tan δ, the dielectric breakdown test of the cable, and the tensile strength, elongation at break, crystallinity, and dielectric strength of the XLPE specimens. Additionally, the correlation between the VLF Tan δ and other characteristics was also analyzed. It was found that degradation progressed in the order of the BFP, the cooling tower, and the deaerator booster pump. Therefore, it was confirmed that even for the same cable, deterioration varies depending on the installation location. [ABSTRACT FROM AUTHOR]

The advancement of novel water treatment technologies requires the implementation of both accurate data measurement and recording processes. These procedures are essential for acquiring results and conducting thorough analyses to enhance operational efficiency. In addition, accurate sensor data facilitate precise control over chemical treatment dosages, ensuring optimal water quality and corrosion inhibition while minimizing chemical usage and associated costs. Under this framework, this paper describes the sensoring and monitoring solution for a hybrid system based on a cooling tower (CT) connected to mechanical vapor compression (MVC) equipment for desalination and brine concentration purposes. Sensors connected to the data commercial logger solution, Almemo 2890-9, are also discussed in detail such as temperature, relative humidity, pressure, flow rate, etc. The monitoring system allows remote control of the MVC based on a server, GateManager, and TightVNC. In this way, the proposed solution provides remote access to the hybrid system, being able to visualize gathered data in real time. A case study located in Cartagena (Spain) is used to assess the proposed solution. Collected data from temperature transmitters, pneumatic valves, level sensors, and power demand are included and discussed in the paper. These variables allow a subsequent forecasting process to estimate brine concentration values. Different sample times are included in this paper to minimize the collected data from the hybrid system within suitable operation conditions. This solution is suitable to be applied to other desalination processes and locations. [ABSTRACT FROM AUTHOR]

Ground‐coupled heat exchangers (GCHE) have received significant attention over several decades as a result of increasing the world's energy demand and the need for reducing fossil fuels consumption. Prior studies have demonstrated the effectiveness of utilizing GCHE with refrigeration and heating systems. However, optimizing the performance of GCHE coupled with chillers for heat rejection, especially in extreme hot‐humid climates (where cooling towers are not very effective) is lacking in the literature. In this work, a ground borehole fitted with a coaxial‐tubes heat exchanger (BHE) is numerically simulated. Based on a wide range of data collected for the soil of Dubai, its real in situ thermophysical properties are characterized. The soil's upper layer thickness is relatively small and dry that operates in conduction mode, while the lower one is water‐saturated that works in coupled conduction‐advection mode. The study aims at optimizing the parameters advancing heat rejection into ground considering the actual properties of the soil of Dubai. The results indicate that the more feasible high‐density polyethylene pipes can perform as good as the steel ones. Also, a great finding based on the presented novel design is that insulating the inner pipe can increase the temperature duty by 55%. The proposed design of BHE is relatively inexpensive, more feasible and efficient, which is achieved for the first time based on a deep analysis of Dubai climate and soil. This makes the technology ready to be implemented for industrial applications in Dubai and other regions having a similar climate and soil nature. [ABSTRACT FROM AUTHOR]

The Rainwater Harvesting Tool is a publicly available web-based geographic information system tool. It was developed using geospatial analysis in combination with historic zone improvement plan (ZIP) Code–level monthly average precipitation and evapotranspiration data across the US to help select potential locations for harvesting rainwater. Rainwater harvesting can provide a key alternative water source for a variety of uses, including landscape irrigation, vehicle washing, cooling tower make-up, dust suppression, and toilet flushing. Rainwater harvesting can help to diversify water sources for institutional, commercial, and residential buildings and offset the use of treated potable water. This tool aims to help organizations strategically target locations in which to implement rainwater harvesting systems. The metric used in the tool is called the rainwater harvesting potential, which is a normalized metric. The rainwater harvesting potential describes the amount of rainwater that reasonably can be collected and stored at a specific location. This metric was used to rank areas delineated by ZIP Codes across the US from lowest to highest to show the relative availability of rainwater for harvesting. Two mapping layers are included in the tool: a layer that shows the general year-round rainwater harvesting potential, and a layer that specifically shows the potential for harvesting rainwater to supply irrigation water. The Rainwater Harvesting Tool allows users to view the overall trends across the US and view the data at a scale at which the ZIP Code boundaries are clearly delineated. The tool can be used to help organizations with buildings located in multiple regions to strategically identify where to install rainwater harvesting systems and prioritize locations that may be optimal for rainwater harvesting. The Rainwater Harvesting Tool is a web-based geographic information system tool, which is free and available to the public. The tool presents the rainwater harvesting potential across the US to help determine locations that are potentially good candidates for harvesting rainwater and capable of meeting the water demands of institutional, commercial, and residential buildings. Rainwater can supply water for irrigation, cooling towers, vehicle washing, toilet flushing, and so forth, and offsets the use of treated potable water. The tool contains two mapping layers. The first shows the general potential for capturing rainwater and indicates the relative ability of a given location to collect rainwater throughout the year for beneficial use. The second identifies areas with favorable precipitation patterns for collecting rainwater during the irrigation season. The Rainwater Harvesting Tool provides interactive functions within a single browser session. Users enter specific locations (by ZIP Code), and the tool outputs a relative rank of the harvesting potential. The amount of rain potentially harvested each month also is provided. This portfolio planning, decision support tool can be utilized by organizations to target locations that are most conducive for rainwater harvesting across many locations. [ABSTRACT FROM AUTHOR]

• A MISSA algorithm is proposed to solve the central air conditioning energy-saving problem. • Cooling load prediction provides a foundation for energy-saving optimization. • The three improved strategies are introduced to obtain better operating results. • The experimental results indicate that the MISSA can find a better optimal solution. Aiming at the problem of high energy consumption caused by the nonlinear, strong coupling, and large hysteresis characteristics of central air conditioning (CAC) system, an energy-saving optimization method based on WTD–CNN–LSTM and multi-strategy improved sparrow search algorithm (MISSA) is proposed, which works to minimize the total energy consumption during the operation of the CAC system. Firstly, minimize the sum of energy consumption of chillers, freezing pumps, cooling pumps, and cooling towers as the objective function, and use the range of operating parameters of each equipment as the basic constraint conditions to establish an energy-saving optimization model for the CAC system. Then, WTD–CNN–-LSTM is used to predict the future cooling load, and the predicted results are used as key constraint condition to achieve on-demand cooling. Finally, MISSA is proposed to improve the initialization, update and convergence stages of the CAC system operation parameter optimization process, accurately obtaining the optimal operating parameters. Compared with manual experience, MISSA reduces energy consumption by 15.32 % and improves energy efficiency ratio by 20.76 %. Meanwhile, compared with other optimization algorithms, MISSA reduces energy consumption by 4.85–13.26 % and improves energy efficiency ratio by 6.53–16.33 % after optimizing the CAC system. The experiment verifies that MISSA is more energy efficient when applied to the CAC system and has the advantages of accuracy, fast convergence, strong global search capability, and the ability to jump out of local optimization. [ABSTRACT FROM AUTHOR]

The layout of multiple natural draft dry cooling towers could have a significant influence on the performance of the cooling system in concentrated solar power (CSP) plants; however, this has never been quantified. Hence, this work used computational fluid dynamics (CFD) modeling to analyze the cooling capacity of two short natural draft dry cooling towers (NDDCTs) on a common site for a range of tower spacings, wind-speeds, and wind incidence angles. The results show that the cooling performance of the towers is a strong function of tower spacing and their orientation with respect to the wind direction. It was found that when the wind came at a 90-deg wind incidence angle (i.e., normal to a line drawn between the two towers), their cooling capacity was improved at tower spacings of less than 1.8 tower diameters (1.8D), though for the other tower spacings, there was no interaction between the towers. However, with the wind at 45 deg to the towers, the flow around the towers resulted in a decrease in their cooling capacity at tower spacings of 1.8D and 2.6D. Most interestingly, it was found that orienting the towers in line with the prevailing wind direction delivered improvements in the cooling capacity of up to 30%. This is due to the windward tower acting as a passive windbreak. Hence, as CSP plant capacity is increased, and additional cooling towers are required, these should be placed close to any existing tower and oriented along the line of the prevailing winds. [ABSTRACT FROM AUTHOR]

This article presents a comparative simulation-based control logic design process. It uses the Control Description Language (CDL) and the ASHRAE Guideline 36 high-performing building control sequences with the Modelica Buildings Library (MBL) to demonstrate a comparative analysis of two control designs for a data center chilled water plant. Details include a description of the closed-loop plant and control design methodology, including sizing and parameterization, base and alternative (Guideline 36) control logic with software implementation structure, and outline of the simulation experimentation process. The selected control designs are paired with comparable chilled water plant configurations. The models include a chiller, a water-side economizer, and an evaporative cooling tower. The plant provides cooling at 27ºC zone supply air temperature to a data center in Sacramento, CA. The comparative simulation results examined the impacts of a selected control logic detail, and present an example model-based design application. Overall, the simulation results showed a 25% annual and a 18% summer energy use reduction for alternative controls. This shows that simulation-based control logic design performance evaluation can improve energy efficiency and resilience aspects of system controls at large. [ABSTRACT FROM AUTHOR]

As the key heat transfer element of natural draft dry cooling towers, the columnar cooling tube bundle radiator is composed of four rows pipe or six rows pipe, and usually arranged as per delta, which would induce a large vortex around the delta under crosswind conditions, and then impact the cooling performance of cooling deltas and that of the total Tower. To overcome this shortage, this study proposed a cooling column with a gap between the upstream pipes and downstream pipes in one cooling column, which can introduce a stream of air jet flow into the columnar cooling tube bundle and then impact the aerodynamic field of the tube bundle and the corresponding cooling delta. A three-dimensional numerical model has been established to compare and study the cooling characteristics of the cooling columns with wedge-shape gap and the usual. The results show that the wedge gap can increase the heat transfer coefficient of the radiator and decrease its flow resistance coefficient. At 7 m/s crosswind, the outlet water temperature of dry tower by using the usual radiator is 36.46 °C, while that is 34.23 °C for dry cooling tower with wedge radiator. [ABSTRACT FROM AUTHOR]

Spatial truss structures (STSs), serving as the bottom support structure of a cooling tower, effectively harness the superior load-bearing capacity offered by lattice-type truss structures. STSs are composed of main bars, diagonal bars, and horizontal bars, with horizontal bars serving as vital components of the truss structure. They play a pivotal role in maintaining the overall integrity and stability of the structure. The proportional relationship between the stiffness of each bar in STSs has a profound impact on the mechanical characteristics of the overall structure. This relationship directly influences the ultimate load-bearing capacity of the structure. Therefore, conducting research on the influence patterns of this relationship is of utmost importance. This paper explores the study of triangular truss structures (TTSs) and quadrilateral truss structures (QTSs). Firstly, through theoretical analysis, considering structural elements such as the stiffness of the horizontal bars, the number of layers in the truss, and the angle between the diagonal bars and the horizontal bars, theoretical expressions for the calculation of the ultimate load capacity of TTSs and QTSs are derived. Furthermore, a parametric finite element (FE) model was established for the TTSs and QTSs. Through numerical simulations, the validity of the theoretical calculation expressions was verified. Finally, this paper discusses the influence of factors such as the stiffness of the horizontal bars, the number of layers in the truss, and the angle between the diagonal and horizontal bars on the TTSs and QTSs. It analyzes the patterns and trends of these influences. The research results indicate that the theoretical and numerical simulation results for the TTSs have an error ranging from 0.40% to 4.93%, while the relative error for the QTSs ranges from 1.59% to 4.88%. These errors are within an acceptable range for engineering calculations. As the stiffness of the horizontal bars increases, the proportionality coefficient of the truss's ultimate load capacity shows an initial increase followed by a stable trend. It reaches an equilibrium state when the stiffness of the horizontal bars reaches a certain threshold. As the number of layers in the truss and the angle between the diagonal and horizontal bars increase, the proportionality coefficient of the load capacity gradually decreases. The research findings provide a theoretical basis for the application of TTSs and QTSs in cooling towers. [ABSTRACT FROM AUTHOR]

The aim of this article is to identify, based on a literature review, the most suitable water treatment technologies for the production of reuse water to be used by industries that are often present in the Brazilian semi-arid region. For this research, we selected studies on water treatment with low implementation costs and advanced development for implementation. This study identified water treatment technologies for the production of reuse water in the leather and footwear, textile, metallic and non-metallic mineral extraction and food and beverage industries. The search was carried out in the scientific databases Scopus and Web of Science, with no restrictions on the year of publication. Based on the selected articles, a summary was made of the most suitable water treatment systems for each industrial sector, providing an overview of the treatments recommended for water-scarce regions. Water reuse can be implemented in various industrial activities, including the use of boilers, cooling towers, toilet flushing, local irrigation and reintroduction into the process as a by-product. There are various methods of water treatment, although it is necessary to assess which is most suitable for each type of industry. Aspects such as the amount of effluent generated, the necessary properties of the water to be reused and the cost of the project must be carefully evaluated if the benefits are to be achieved. [ABSTRACT FROM AUTHOR]

Background: Cooling towers are specialized heat exchanger devices in which air and water interact closely to cool the water's temperature. However, the cooling water contains organic nutrients that can cause microbial corrosion (MC) on the metal surfaces of the tower. This research explores the combined wastewater treatment approach using electrochemical-oxidation (EO), photo- oxidation (PO), and photoelectrochemical oxidation (PEO) to contain pollutants and prevent MC. Methods: The study employed electro-oxidation, a process involving direct current (DC) power supply, to degrade wastewater. MC studies were conducted using weight loss assessments, scanning electron microscopy (SEM), and x-ray diffraction (XRD). Results: After wastewater is subjected to electro-oxidation for 4 h, a notable decrease in pollutants was observed, with degradation efficiencies of 71, 75, and 96%, respectively. In the wastewater treated by PEO, microbial growth is restricted as the chemical oxygen demand decreases. Discussion: A metagenomics study revealed that bacteria present in the cooling tower water consists of 12% of Nitrospira genus and 22% of Fusobacterium genus. Conclusively, PEO serves as an effective method for treating wastewater, inhibiting microbial growth, degrading pollutants, and protecting metal from biocorrosion. [ABSTRACT FROM AUTHOR]

Contaminants from cooling water waste (CWW) generated by industries represent an environmental hazard if discharged into aquatic bodies and soil without treatment. Most treatment strategies are energy-demanding and costly; hence, low-cost and sustainable treatment alternative technologies are needed. The present study proposed cyanobacteria culture as a low-cost biological method to treat cooling water waste (CWW) while simultaneously producing carbohydrates. For this purpose, CWW from a cooling tower was evaluated in different dilutions with domestic wastewater (DW) (DW25% -CWW75%, DW50% -CWW50%, DW25% -CWW75%, DW100%, and CWW100%) (v/v). The CWW provided a high content of inorganic carbon and low content of N and P, which resulted in a high C/N ratio promoting a fast carbohydrate accumulation but low biomass production. In contrast, cultures with higher DW concentrations achieved similar results in 14 days. The best results were obtained with DW25% -CWW75%, achieving up to 52 ± 18% carbohydrate content on day 8, with the highest biomass concentration of 1.7 ± 0.12 g L−1 on day 14. This culture removed >94% of TAN, N-NO3- and P-PO43-, and 84 ± 10.82% of COD. This strategy could be a promising approach to treating CWW and DW from the same industry and producing value-added products and bioenergy. [ABSTRACT FROM AUTHOR]

Based on the design and measured data of one actual tower, a three-dimensional numerical model for a natural draft dry cooling tower (NDDCT) was created and validated under constant heat load. This enabled the performance improvement mechanism of air equalizing on vertical delta-type radiators (VDRs) to be clarified by detailed analysis of key parameters, such as the exit water temperature, heat transfer coefficient, and mass airflow. Under the impact of typical ambient crosswind, all VDRs were retrofitted with air-side-equalizing devices. It was found that the exit water temperatures of the whole NDDCT decreased by 0.865 °C, 0.593 °C and 0.186 °C under the studied ambient crosswind speeds of 2.5 m/s, 4 m/s and 12 m/s, respectively. The performance improvement mechanism of air-side equalizing was investigated for three VDRs, which were located on the upwind, tower lateral, and downwind sides under crosswind impacts. Besides the studied VDRs, the performance of the neighboring VDRs behind them was also improved by the optimized aerodynamic field and the reduced hot wind recirculation around them. In addition, the average heat transfer coefficients of the VDRs were enhanced, which could lay the foundation for improving the cooling performance of thermodynamic devices with VDRs. [ABSTRACT FROM AUTHOR]

• The positive pressure condensation dehumidification method for humid air is proposed. • The heat and mass transfer model of the new dehumidification process is developed. • Condensation dehumidification experiments with different pressures are carried out. • Heat and mass transfer rate is about 3 times higher than that at atmospheric pressure. • Air humidity after dehumidification is less than half of that at atmospheric pressure. Air condensation dehumidification is the main dehumidification method, which dehumidifies by cooling the air temperature below its dew point temperature. The process of atmospheric condensation dehumidification requires chillers to obtain lower temperature cooling sources, which leads to reheat loss. In this paper, the positive pressure condensation dehumidification method for humid air is proposed, as the dew point temperature of air is increased with the pressure. By this way, natural cooling sources or evaporative cooling towers can be used instead of refrigeration systems for cooling and dehumidification. The heat and mass transfer model of the positive pressure condensation dehumidification process for humid air is developed, which has three parts: single droplet part, droplet growth part, and single tube condensation part. Positive pressure condensation dehumidification experiments with different pressures are carried out, and experimental results show that the model accuracy is within ± 10 %. Additionally, theoretical results indicate that the heat and mass transfer rate within the pressure range of 160–290 kPa is about 2.5–3.4 times higher than that at atmospheric pressure, and the humidity of the air after dehumidification is 15.6–10.9 g/kg, which is less than half of that at atmospheric pressure. [ABSTRACT FROM AUTHOR]

The world's population is expected to increase by nearly two billion in the next 30 years; the population will increase from 8 billion to 9.7 billion by 2050 and could peak at 10.4 billion by the mid-2080s. The extreme weather triggered by global climate change has severely hit crop yields in open-field cultivation and led to an increase in food prices. Furthermore, in the last few years, emergency events such as the COVID-19 pandemic, wars/conflicts, and economic downturns have conditioned agricultural production and food security around the world. Greenhouses could be efficient cultivation systems because they enable food production in a sustainable way, limiting contact between pollutants and plants and optimizing the use of water, energy, and soil. This paper proposes a novel dome-soilless greenhouse concept for tomato cultivation in the Mediterranean area. The proposed greenhouse is fixed on a sea platform to take advantage of the seawater cooling environment and to integrate water consumption into a hydroponic system. In order to evaluate the best covering solution material to adopt, a few thermal and photometric characteristics of greenhouse covering materials were evaluated using a simplified method. A dynamic simulation was carried out to compare the proposed seawater cooling system with a conventional cooling tower in terms of the electric energy spent to maintain the inside temperature range at 13–25 °C across all seasons in the year. The proposed heating, ventilation, and air conditioning (HVAC) system allowed a total annual energy saving of more than 10%. The energy saved was a result of the better cooling performance of the seawater heat exchange that allowed energy saving of about 14% on cooling. The comparison between the model characterised by a 6 mm polycarbonate coupled with UbiGro film and a seawater cooling system, and the model including a 6 mm polycarbonate coupled with a clarix blue film covering and a tower cooling system highlighted energy saving of about 20%. The obtained results indicate possible future directions for offshore greenhouses to carry out independent production together with the integration of photovoltaic modules, water treatment plants, and smart remote-control systems. [ABSTRACT FROM AUTHOR]

In this study, the tallest cooling tower (228 m) completed construction in the world in northwest China was chosen to investigate wind-induced failure mechanism of superlarge cooling towers under tornado. A multiscale finite-element model of the structure was established based on the layered shell element method, and a wind tunnel pressure test was carried out using the tornado simulator. Wind pressure distribution characteristics on inner and outer surfaces of the cooling tower under tornado were analyzed. Moreover, characteristics of the whole wind-induced collapse process of the cooling tower under tornado were studied by combining incremental dynamic analytical method, and the collapse mechanism of a superlarge cooling tower under tornado was extracted. Finally, the failure criterion of the structure under tornado based on the variation rate of the torsion angle was proposed. Results demonstrated that wind pressure showed a circumferential even distribution pattern on the surface of the superlarge cooling tower under tornado, and it generally presented negative pressures. When the cooling tower is located at the tornado vortex core, it is the most dangerous and vulnerable to collapse. Under tornado effects, the cooling tower presented bypassing suction and torsional collapse attitudes from inside to outside. The cooling tower element is designed to improve the antitornado bearing capacity by developing a membrane mechanism. The cooling tower collapsed and failed when the torsion angle failure index φ>0.25. [ABSTRACT FROM AUTHOR]

Nowadays, axial fans participate in the most important areas of industry and research, including aviation, navy, wind tunnels, cooling towers, and even automobiles. Thus, more emphasis has been placed on improving their aerodynamic performances. It is important to notice that the parameters involved in designing a fan are mainly concerned with aeraulic power, torque and efficiency. This study investigates the utilization of flow control techniques to improve performances of an axial fan equipped with hollow blades, shroud, and hub. These features grant the fan crucial characteristics, namely, its lightweight and facilitate the blowing action by taking advantage on its hollow parts. The fan's performance is evaluated using a steady RANS numerical model with a k-ω SST turbulence closure, which was validated with experimental data. An active control air blowing through a slot was introduced with various positions and dimensions. The results demonstrate a significant improvement in the fan's performance, with an up to 56% increase in aeraulic power gain, accompanied by changes in the overall flow topology, noticed by closely analyzing the flow structure near the tip clearance. [ABSTRACT FROM AUTHOR]

Thermal power units play a crucial role in the deep peak regulation of power generation. During deep peak regulation, the load of the unit changes significantly, causing fluctuations in the inlet water temperature of the cooling tower and the water temperature in the filler. Therefore, in cold regions in winter, cooling towers have a high risk of freezing, which threatens the economic and safe operation of the unit. This paper establishes a three-dimensional numerical model based on constant heat dissipation and explores the average and minimum water temperatures at the bottom of filler under different water distribution methods, crosswind velocities, and ambient temperatures. The results show that the water distribution method has a significant impact on the water temperature at the filler bottom. Reducing the water distribution area can significantly increase the minimum water temperature at the filler bottom and reduce the risk of freezing. Although the presence of crosswind is not conducive to the cooling performance of the cooling tower, the higher the crosswind velocity, the higher the minimum outlet water temperature at the filler bottom and the lower the risk of freezing. The minimum water temperature at the filler bottom is approximately linearly related to the ambient temperature and is less affected by the unit load at the same temperature. [ABSTRACT FROM AUTHOR]

Legionella pneumophila is a gram‐negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase‐like metabolic changes via alternative sigma factors, and two‐component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity. [ABSTRACT FROM AUTHOR]

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In the present study, a techno-economic analysis for the reclamation of wastewater in a midstream petrochemical factory (the Miaoli factory of the China Petrochemical Development Company in Taiwan) was investigated. Caprolactam is the main product in this factory. The wastewater to be reclaimed and recycled as cooling water replenishment was the effluent from organic- and inorganic-based wastewater treatment plants, the concentrate from cooling tower units, and water for rinsing use from other units. In addition to the current primary treatment process (Scheme 1), other treatment methods involving various combinations of membrane-based processes of microfiltration (MF), ultrafiltration (UF), reverse osmosis (RO), and electrodialysis reversal (EDR) were proposed, depending on the quality of the wastewater. The three schemes include the combination of MF and EDR (Scheme 2), UF and RO (Scheme 3), and MF, UF and RO (Scheme 4). Based on the capacities and operating costs of various membrane modules, an economic analysis on Schemes 2–4 by the net present worth method demonstrated that Scheme 3 was the best choice under the range of source water price studied (U$ 0.45–0.62/m3). In this case, the total amount of wastewater reclaimed notably increased from 6.6% by the current treatment scheme (Scheme 1) to 30.9% by Schemes1 and 3. Moreover, Scheme 3 had an advantage over Scheme 1 when the source water price exceeds U$ 0.51/m3. [ABSTRACT FROM AUTHOR]

The water of Persian Gulf, which is currently used as the water in the cooling tower for Bandar Abbas power plant has high alkalinity, conductivity and salinity. The examination of microbial tests for the cooling tower indicates the high concentrations of all kinds of microbial species which is related to the high level of fluoride, sulfate ions and sediments. The TBC shows 104 cfu/ml which is considered a high value. On the other hand, the presence of magnesium and calcium ions in carbonate form is a reason for the huge amount of hardness. The high level of ions concentration especially chloride and magnesium in the cooling water increase the growth of microbial parameters. Furthermore, the reason of such a huge growth of sulfate-reducing bacteria (SRB) is the high concentration of sulfate. Therefore, the solution of reducing the general concentration of ions using methods such as reverse osmosis and ion exchange resins is suggested as the first priority to prevent microbial corrosion. Additionally, chlorination methods are proposed as the second priority due to economic efficiency and high-performance capability. Finally, ozonation method is presented as the third priority due to the higher cost compared to chlorination, high power and the absence of side products. Also, the high concentration of sulfate leads to the activity of SRB bacteria and causes various types of corrosion, and therefore, the use of methods for reducing the concentration and selective removal of sulfate as an effective and priority solution should be considered. [ABSTRACT FROM AUTHOR]

In recent years, the treatment and reuse of wastewater have been widely of interest due to the severe shortage of water resources. As is well known, a huge amount of water is consumed in coal-fired power plants, especially for the circulation cooling system in a cooling tower. Therefore, research on the circulating cooling system and cooling tower blowdown water (CTBD) treatment is crucial. In this study, a computational model was established to study the treatment of CTBD by reverse osmosis (RO) and direct contact membrane distillation (DCMD). Recycled fresh water was used as a water supply for the cooling tower. The effects of the main operating parameters on the performances of the RO and DCMD with/without waste heat utilization were explored. The water-saving effects, energy consumption amounts, and economics of the three systems were analyzed comparatively. The results showed that better water-saving performance of the DCMD with waste heat utilization was achieved with a water-saving rate of 18.4% and that the energy consumption and cost were slightly lower than those of the RO. The lowest water treatment cost of the DCMD with waste heat utilization was 3.38 Ұ/m3. In addition, the effect of electricity price on the costs was studied. When the electricity price was higher than 0.31 Ұ/kWh, the DCMD with waste heat utilization was more economical. • Techno-economy of three water-saving systems is designed and assessed. • The waste heat utilization improves the economy of membrane distillation. • Membrane distillation with waste heat recovery reduces water consumption by 18.4%. • Performance of the improved membrane distillation and reverse osmosis is compared. [ABSTRACT FROM AUTHOR]

In the Ecuadorian context, cooling technologies play a critical role in the operation of thermoelectric power plants. These technologies are essential to maintain the efficiency and reliability of power generation plants, which can use a variety of methods to cool their systems. Cooling towers are becoming a common option in Ecuador, allowing heat to be dissipated through the evaporation of hot water. In addition, heat exchangers play an important role in transferring heat from one fluid to another, contributing to the energy efficiency of power plants. However, the country also faces challenges related to the availability of water resources and environmental sustainability. The use of cooling water can raise environmental concerns, especially in a country with rich biodiversity and high dependence on natural resources. Therefore, this paper looks at the experiences of operators and finds that factors such as resource availability, environmental regulations and operational efficiency need to be carefully considered when selecting cooling technologies in Ecuador. Cooling solutions require a balanced approach that ensures reliable and efficient power generation while minimizing environmental impact and protecting the country's unique biodiversity. [ABSTRACT FROM AUTHOR]

Ensuring the structural integrity of cooling towers is paramount for safety and efficient operation. This paper presents a novel approach for detecting damage on cooling tower shells, utilising textures derived from laser scanning and close-range photogrammetry. The proposed method delves beyond the limitations of solely relying on colour information by harnessing the rich details embedded in various textures, including diffuse, normal, displacement, and occlusion. The study demonstrates the efficacy of this approach for identifying significant concrete damage. A Convolutional Neural Network (CNN) trained on diffuse textures successfully detects high damage instances with minimal misdetection. However, accurately pinpointing low damage, often manifesting as subtle cracks, and mimicking other patterns like air pores, ribbing, and colour variations, presents a formidable challenge. To tackle this challenge, the authors introduce a novel "composed raster layer" that merges information from multiple textures. This pre-processed layer amplifies the visual cues associated with low damage, facilitating its differentiation from similar patterns. While the current implementation employing multi-resolution segmentation and rule-based classification exhibits promising results, further optimization is acknowledged to refine the accuracy of low damage detection. The successful application of textures commonly used in rendering techniques underscores their remarkable potential for enhancing damage detection in civil engineering applications. While acknowledging limitations such as the analysis of a single cooling tower and the reliance on specific software for damage detection, the study proposes future research directions. This research holds significant implications for the field of civil engineering by offering a promising approach for automated and efficient damage detection on cooling tower shells. [ABSTRACT FROM AUTHOR]

The water of Persian Gulf, which is currently used as the water in the cooling tower for Bandar Abbas power plant has high alkalinity, conductivity and salinity. The examination of microbial tests for the cooling tower indicates the high concentrations of all kinds of microbial species which is related to the high level of fluoride, sulfate ions and sediments. The TBC shows 104 cfu/ml which is considered a high value. On the other hand, the presence of magnesium and calcium ions in carbonate form is a reason for the huge amount of hardness. The high level of ions concentration especially chloride and magnesium in the cooling water increase the growth of microbial parameters. Furthermore, the reason of such a huge growth of sulfate-reducing bacteria (SRB) is the high concentration of sulfate. Therefore, the solution of reducing the general concentration of ions using methods such as reverse osmosis and ion exchange resins is suggested as the first priority to prevent microbial corrosion. Additionally, chlorination methods are proposed as the second priority due to economic efficiency and high-performance capability. Finally, ozonation method is presented as the third priority due to the higher cost compared to chlorination, high power and the absence of side products. Also, the high concentration of sulfate leads to the activity of SRB bacteria and causes various types of corrosion, and therefore, the use of methods for reducing the concentration and selective removal of sulfate as an effective and priority solution should be considered. [ABSTRACT FROM AUTHOR]