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Cooling towers are high and thin structures which are widely used at the industry and nuclear facilities. These structures are built on column elements as reinforced concrete. Determining the behavior of the buildings affected by the dynamic loads such as wind and earthquake is very important in terms of preventing the loss of life and property. In this study, hyperbolic cooling with 117m height tower was examined and the behaviors of the structure in earthquake and wind effects were investigated. During the application of the wind load, 25m / sec wind velocity was applied and three ground motion records were applied to the structures in the course of the earthquake analysis. The wind load was calculated in accordance with the ASCE 7-10 standard and it was given as angular. As a result of the analysis, the values of the displacement and stress were obtained and examined. According to the results of the wind load analysis; As the height of the tower increases, the values of wind load increase and the displacement values occurring in the building increase. The values of displacement and stress vary angularly depending on angular wind load. It is seen that the highest values of displacement and stress values were obtained in Kobe earthquake. Displacement values were examined depending on the height and the largest displacement values were obtained at the top part.

Sensible and latent heat rejection from heat engines is of high necessity for system efficiency and continuous production. The cooling tower is one of the major heat-exchanging systems used for cooling industrial heat systems by intimately mixing hot water with cooling air. Optimal operating conditions and parameters of the system are highly essential for its effectiveness and efficiency. This study used the Poppe model to evaluate selected thermodynamic relations of a rectangular counter-flow industrial cooling tower of a steel rolling mill using the system’s inlet and outlet data as initial conditions. The effect of increasing the water temperature on the air moisture content, Merkel number, and specific enthalpy was studied across the fills of the cooling tower. Air moisture content, Merkel number and specific enthalpy of the system increase with increasing water temperature. However, while other variables reach a stationary point at half the nodal segments, the specific enthalpy increases across the fills in the system. It was concluded that the use of nano particles with high heat removal rate could increase the efficiency of the system. Also, an increase in the quantity of the makeup water of a force draft system is recommended towards increasing the system efficiency.

Visible plumes above wet cooling towers are of great concern due to the associated aesthetic and environmental impacts. The parallel path wet/dry cooling tower is one of the most commonly used approaches for plume abatement, however, the associated capital cost is usually high due to the addition of the dry coils. Recently, passive technologies, which make use of free solar energy or the latent heat of the hot, moist air rising through the cooling tower fill, have been proposed to minimize or abate the visible plume and/or conserve water. In this review, we contrast established versus novel technologies and give a perspective on the relative merits and demerits of each. Of course, no assessment of the severity of a visible plume can be made without first understanding its atmospheric trajectory. To this end, numerous attempts, being either theoretical or numerical or experimental, have been proposed to predict plume behavior in atmospheres that are either uniform versus density-stratified or still versus windy (whether highly-turbulent or not). Problems of particular interests are plume rise/deflection, condensation and drift deposition, the latter consideration being a concern of public health due to the possible transport and spread of Legionella bacteria.

The cooling water system is an indispensable part in the removal of the indoor cooling load in heating, ventilation, and air‐conditioning (HVAC) systems. However, the complexity and strong coupling characteristics of the controlled objects lead to unsatisfied control effects in most practical engineering applications. In this paper, the cooling water system is studied as a whole from the perspective of online application. Firstly, the mathematical models of the cooling water system are introduced and simplified based on the experimental data from the actual system. The simplified models have easy obtained inputs and programmable structure, which renders higher feasibility and practicality for the model‐based control method applied in the real system. On this base, an easily implemented control method for cooling water system is proposed to improve the global efficiency. By comparing with the conventional constant temperature difference control strategy and constant speed control strategy in the simulation platform, the proposed water flow optimization control strategy is superior in both global COP and energy saving at the same operating conditions, and 0.37% and 3.45% of energy consumption can be saved, respectively. The simulation results imply that the proposed simplified method is a referable control method for designing or retrofitting the real cooling water system.

Introduction. To use natural sources in rational way, plantsof continuous cooling of closed systems of recycling water supply are used. The paper presents designs of small-sized devices for recycling water cooling which are energy resource effective due to twisted motion of air flow, moving countercurrent to the cooled water. Heat and mass transfer is a nanotechnological process that occurs at the intermolecular level. Methods and materials. Countercurrent mini cooling towers are widely used in all industries,but there are some disadvantages, the main of which is the insufficient interaction time of the moving phases. Screw motion of air flow is created by the tangential supply of cooling air in the bottom part of cylindrical small-sized cooling tower. The rate of rotary motion decreases as air flow moves up in cooling towers, and vertical parameter of the rate – increases. Such scheme of the air flow motionmakes it possible to decrease average vertical parameter of the rate and to increase phases contact time. Laboratory research. To determine the technological and hydroaerothermal characteristics, as well as to estimate the efficiency of cooling recycled water, and to carry out mass-heat exchange at the intermolecular stagean experimental facility of small-sized cooling tower with twisted air flow has been developed. Conclusions. In accordance with the exponential law it is shown that the rotational component decreases at increasing height, and in accordance with the power law the vertical component increases component with the exponent ~1,79. It is determined that moisture content x and air temperature tv in the volume of the height of the sprinkler varies according to a power law, in particular for a screw cooling tower proportionally x ~ h0,83, t в ~ h1,25. It was determined that the coefficients of mass transfer βxv and heat transfer αv of a mini cooling tower with twisted air flow at the intermolecular level with equal irrigation densities are 20% higher than the coefficients of a mini cooling tower with counter-current flow. Also it has been determined experimentally a dependence of aerodynamics resistance coefficient of the twisted irrigator of the cooling tower on criterium Refor air flow, and it was determined that it decreases like Re–K2 as the exponent K2 varies in the range 0.114÷0.193 depending on the irrigation density

As global warming and water scarcity issues continue to grow, it is essential to increase resources efficiency for air conditioners and power plants. In order to increase the efficiency, the systems need to be modified to take the advantages of the low night temperature and thermal storage tanks. In this study, the low night temperature and thermal storage tanks effects on the cooling tower is studied using TRNSYS. Using a chiller operating from 8:00 to 16:00 as a case study, hot water from the condenser is partially stored on daytime and cooled slowly during the night. The storage tank volume is optimized by considering two big tanks and five small tanks. The results show that night cooling reduces cooling water temperature by 5.8 °C or 21.8% while the cooling efficiency is increased by 36%. The thermal storage tanks enable to have the low continuous flow rate and help to reduce the fan power by 67.1%. On the storage side, compared to two tanks system, the tanks volume is reduced by 16.5% when 5 tanks are used. In theory this reduction can go up to 50% by increasing the number of tanks and reducing their individual size.

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%.

In order to improve the economic performance of the company, the establishment of rational water use schemes and the reduction of the use of fresh water obtained from water supply systems or natural bodies of water can become an important factor. Water-cooling circulating systems, where cooling towers are used as cooling facilities, are the basis of rational water use systems. In water recycling systems that need stable water cooling at high specific hydraulic and thermal loads, cooling towers are used. By spraying water with nozzles or irrigation devices, the surface of water needed to cool it by contact with air is formed. A cooling tower is a heat exchange device for removing heat from various production processes to the environment by evaporating part of the water passing through it. The share of evaporated water usually does not exceed 1.5 %. Most of the cooling towers used were built 30 - 50 years ago. Almost all of these installations are morally and physically outdated. To consider the main criteria that should be guided with the choice of method for reconstruction of cooling towers to increase the efficiency and effectiveness of their operation.

This work presents failure investigation of cooling tower fan-arms commissioned in a chemical processing plant. The analysis aims at understanding the mechanism and root-cause of the failure. The investigation involves site visits, microstructural analysis, fracture surface analysis, hardness measurements, numerical stress analysis and experimental simulation. Work concludes that the fan-arms failed due to the lack of post-weld heat treatment, which caused localized stress-corrosion and pitting at critical locations that served as crack initiation sites. Fatigue loading condition and presence of residual stresses at the weld enabled easy propagation of cracks that led to recurring premature failure. Based on the root-cause and the mechanism identified in this analysis, proper pre-heating and post-weld heat treatment is recommended to relieve the residual stresses at the critical locations and thus to avoid/minimize such recurring failures in future.

Ultraviolet (UV) radiation systems are a common method of inactivating bacteria in municipal water treatment but has not been applied in a paper mill operations. Determining the feasibility of installing such a system is the purpose of this report. Directly treating a starch solution of sufficient concentration proved impossible as the transmittance required was far too low. Water used in the onsite water recycling facility’s cooling towers had a transmittance over 90% and so was very treatable. Lab scale testing with a designed 15 liter laboratory benchtop ultraviolet treatment system showed that UV treatment can reduce the aerobic bacteria count by two fold for up to 24 hour of operation and significantly lower results for 48 and 72 hour of operation. Therefore, UV treatment can be considered a valuable process for the treatment of cooling tower water.

Solar enhanced natural draft dry cooling tower (SENDDCT) is a novel heat rejection device for thermal power plant, which uses solar energy to reheat the air after the heat exchanger and therefore improves the ventilation of the tower for performance enhancement. This paper develops 3-D models to compare the effects of circular/sawtooth arrangements of heat exchanger on cooling performance of a 140 m high SENDDCT. The result shows that sawtooth arrangement can improve the ventilation and heat dissipation rate of SENDDCTs. Under no crosswind condition, the flow field distributions of sawtooth and circular arrangements are similar in the tower. The ventilation and heat dissipation rate of sawtooth arrangement increases by 34.0 % and 46.8 % respectively when compared with circular arrangement under no crosswind condition. Under crosswind condition, the flow field of sawtooth arrangement is less affected by crosswind than that of circular arrangement. The ventilation rate and heat dissipation rate of sawtooth arrangement increases by 38.5 % and 65.0 % respectively when compared with circular arrangement at crosswind speed of 3 m/s. This study verifies that the sawtooth arrangement can weaken the crosswind effect and improve the cooling performance of SENDDCT and provides guidance for the optimal arrangement of heat exchanger for the SENDDCT.

Measuring emissions from stacks is challenging due to accessibility and safety concerns and requires techniques to address a broad range of conditions and measurement challenges. One way to facilitate such measurements is to build an instrument package and then use a crane to hold the package over the emissions source. Here we describe such an instrument package that is used to characterize both wet droplet and dried aerosol emissions from cooling tower spray drift. In this application, the instrument package characterizes the velocity, size distribution, and concentration of the wet droplet emissions and the mass concentration and elemental composition of the dried PM2.5 and PM10 emissions. Subsequent papers will present and analyze the wet and dried emissions from individual towers.

Environmental problems are frequently related to energy use, estimated to grow at 1.6% per year until 2035. The transport sector accounts for 30% of energy demand and aviation is growing around 2.6% per year. Thus, low-emissions policies promote the use of sustainable aviation fuels. This work simulates a gasification and Fischer-Tropsch process to obtain biojet fuel from biomass and plastic waste. Syngas obtained through cogasification is purified by amine scrubbing and subjected to a Fischer-Tropsch process to produce hydrocarbons, which are upgraded for optimal fuel properties. Pinch analysis is applied to minimize energy usage, while Rankine cycles and a cooling tower are designed to cover the demand of electricity and cooling water. Results show that mass yields of the process towards biofuels are 13.06%, with an output of 1697.45 kg/h of biojet fuel. Density, kinematic viscosity, pour and flammability points and the lower calorific value of the biojet fuel comply with the ASTM D7566 standard. Pinch analysis allows to reduce 41.58% and 100% of cooling and heating demands, respectively, using biomass as renewable energy for heating. Moreover, steam generation covers 38.73% of the required electricity. The produced biojet fuel emits 20.14 gCO2eq/MJ and has a minimum selling price of 1.37 EUR/L.

Wind load is the designed control load for super-large cooling tower (SLCT) structures. Studies on wind resistance of those structures have focused mainly on normal winds, not on the influe...

The current work is focused on the Ground Source Heat Pump Systems (GSHPSs) coupled to closed vertical ground loop. Several factors that affect the system’s performance are examined. Two different approaches are developed. In the first one, an overall view of system’s performance is studied using GLD 2009, GLHEPRO 4.0a and TRNSYS 17. The system is examined as a total of unbreakably connected parts. A parametric analysis is performed to examine the influence of undisturbed ground temperature, Ground Heat Exchanger (GHE) length and borehole separation distance to system’s operational characteristics, so as to cover given building loads. In the second one, the operation of parts is examined independently of the system. The borehole thermal resistance is examined through different types of analysis such as analytical correlations, commercial software GLD 2009 and 2-D finite element analysis through COMSOL 4.0a. Despite the different type of analysis, the deviations are small and that is why borehole thermal resistance output values are considered satisfactory. In addition, MATLAB codes are built to simulate the operation of heat pump and open circuit cooling tower that may be included in a Hybrid Ground Source Heat Pump System (HGSHPS). By studying heat pump’s refrigeration cycle, alternative refrigerant mixtures to R-410A are proposed. Furthermore, the performance of cooling tower is evaluated with the ratio pressure drop per packing height for four packings. The results are generally applicable to the estimation of the performance of these devices and not restricted only to geothermal applications. Moreover, a HGSHPS coupled to a closed circuit cooling tower is studied. A new strategy is developed to control this system so as to minimize its electric power consumption. Despite the fact that it is designed considering only the net cooling period, it is a well-promising policy because it is based on the continuous monitoring of system’s previous hourly state, so as to adjust its operation to the following hour (feedback).%%%%Η παρούσα eργασία eπικeντρώνeται στα συστήματα αβαθούς γeωθeρμίας που έχουν κατακόρυφο κλeιστό κύκλωμα γeωeναλλακτών. Πολλοί παράγοντeς που eπηρeάζουν την απόδοση του συστήματος eξeτάζονται. Δύο διαφορeτικές προσeγγίσeις αναπτύσσονται. Μe την πρώτη, η απόδοση του συστήματος eξeτάζeται συνολικά χρησιμοποιώντας τα λογισμικά GLD 2009, GLHEPRO 4.0a και TRNSYS 17. Το σύστημα eξeτάζeται ως ένα σύνολο από αναπόσπαστα συνδeδeμένα τμήματα. Μια παραμeτρική ανάλυση eκτeλeίται για να μeλeτηθeί η eπίδραση της αδιατάρακτης θeρμοκρασίας του eδάφους, του μήκους του γeωeναλλάκτη και της απόστασης των γeωτρήσeων στα λeιτουργικά χαρακτηριστικά του συστήματος έτσι ώστe να καλυφθούν τα δeδομένα φορτία του κτηρίου. Μe τη δeύτeρη, η λeιτουργία των τμημάτων του συστήματος eξeτάζeται ανeξάρτητα. Η θeρμική αντίσταση της γeώτρησης μeλeτάται μe διαφορeτικά eίδη ανάλυσης όπως μe αναλυτικές σχέσeις, μe το eμπορικό λογισμικό GLD 2009 και μe μια δισδιάστατη ανάλυση πeπeρασμένων στοιχeίων μέσω του COMSOL 4.0a. Παρά τα διαφορeτικά…

Sustainable future and green environment goals quest for the development of technologies to utilize renewable energy resources to power the people. This study focuses on the designing, modelling, and simulation of an absorption solar air-conditioning system. Key performance parameters are identified, optimized for maximum efficiency and simulated in transient energy simulation software TRNSYS ®. The designed model comprises five thermal loops: a solar loop consisting of an evacuated glass tube solar collector having R-410A as heat transfer fluid in it and a heat exchanger heat tank, second loop has an absorption chiller, and an auxiliary furnace with hot water stream, third is the cooling tower loop, the fourth loop is of chilled water from the chiller and the final thermal loop is for air delivery of cooling to each room. The system is simulated using Lahore, Pakistan's climate conditions and offered a good tendency for the proposed system to meet air-conditioning demand at the domestic level. The average collector outlet temperature value of 78 °C has been recorded throughout the week. Collector provides useful energy gain at an average rate of 71,065 kJ/h. Average storage tank temperature at the outlet of heat exchanger is 92°C. Average room temperature values of three rooms are 27°C, 30°C and 19°C respectively.

This paper describes a demonstrative example of an industrial desalination and denitrification system based on renewable energy resources for a sustainable and efficient irrigation. A demo wastewater treatment plant is located in the ArcoSur Mar Menor facilities (Cartagena, Spain) aiming to maximize the reclaimed water recovery from the brine and to remove the relevant pollutants. This demo plant is an industrial combination of biological, membrane separation and thermal technologies that allow us to obtain reclaimed water for irrigation and a dried salt with potential market value. The plant consists of an autonomous renewable energy off-grid solution to cover all energy demand of the brine treatment. Life Desirows European Project also combines different evaporation technologies and includes a cooling tower based on the evaporation of brackish water and consecutive condensation of the generated humid air, mostly at ambient pressure. The project is expected to reduce considerable the energy demand and emissions. This solution is easily extensive toward other areas with similar water scarcity problems, which currently affects at least 10.4% of the EU territory and 14.3% of the EU population, mainly in Southern Europe.

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.

In this study, thermodynamic analysis of a supercritical closed Brayton cycle integrated with parabolic trough solar collectors operating with various organic-based working fluid types is conducted. To examine the performance of this integrated system, a mathematical model, including the energy and exergy analyses of the system, is first developed; after that, a parametric study is performed to determine the effect of compressor pressure ratio, solar irradiation, and type of working fluid on the system performance. In addition, a case study, in which the integrated system is analyzed with the meteorological data of Alasehir, Manisa, Turkey, is conducted in order to assess its monthly performance. The results indicate that when the working fluid is taken as R744 (CO2), the performance of the system gets better compared to that based on other types of working fluids. On the other hand, the case study illustrates that the highest and lowest annual electricity generations are calculated as 7.89 GWh and 2.18 GWh for R245fa and R23, respectively. In addition, the highest and lowest yearly water consumptions in the cooling tower are found as 6680 tonnes and 5870 tonnes for R23 and R245fa, respectively.

The energy consumption of data centres is increasing rapidly. The key to energy saving in the data centre is to reduce cooling energy consumption, resulting from 30–50% of the total power consumpti...

The design and construction of a cold production system from the ice water submitted by a mechanical direct expansion system contributing to the development of knowledge in the area of air conditioning were carried out. Among the technical design parameters, a direct expansion system with cooling capacity of 9000 BTU/Hrs, R134 refrigerant gas to a turbine for the work of the Fan Coil of ½ Hp of force 220 V was selected, as was the fan motor of the cooling tower as fundamental means for heat transfer. The recirculation pumping system is carried out by pumps of 0.37 kW of power and a maximum flow of 40 l/min. For both the evaporator sump (cold) and the condenser sump (hot). The work stage is given in two independent circuits, the Fan Coil system is connected to the evaporator sump and the cooling tower, in turn, is connected to the condensation system for proper operation and achieve condensation temperatures of 35 ° C and in case of having water requirements in the cold sump, the tower is connected by means of an electromagnetic valve for its supply.

Cooling water system (CWS) is a very common system that discharges industrial waste heat. For the existing researches about industrial CWSs, most of them focus on economic performance, ignoring the environmental impact. Based on the industrial foundation, this work proposes a methodology to optimize and evaluate the economic performance and environmental impact. This paper integrates several components, such as cooler network, pump network, cooling tower and air cooler to optimize the total annual cost. Carbon footprint and water footprint are introduced as environmental indicators. The whole system is integrated into Mixed Integer Nonlinear Programming (MINLP) model and solved by GAMS. Through case study, an improved CWS structure chart is obtained, and the relationship between carbon footprint, water footprint and economic performance is drawn, showing the trade-off between the three. The result shows that total annual cost (TAC) can be reduced by 9.84% by economic optimization design. The result also gives a guideline on how to improve environmental performance according to water footprint and carbon footprint.

The cooling tower is a very important building for the thermal power plant. The large steel cooling tower is proposed to overcome the serious challenges that arise from modern cooling towers being higher, larger, and more complex. In this study, for the large-scale hyperbolic steel cooling tower, seven different latticed shell systems with different grid forms, including five double-layer systems and two single-layer systems, were designed and studied in detail. For different heights, grid sizes, and shell thicknesses, numerous parametric analyses (792 models) of the structures were performed. The static behaviors—including the steel quantity, peak displacement, and peak stress—of the seven structural systems were obtained and compared. The variation laws of the steel quantity and peak displacement with respect to the parameters were presented, and the reasonable range of the parameters for the steel cooling tower with different heights were obtained. The results show that the optimal structural system is different for the steel cooling towers with different heights. Additionally, based on the nonlinear stability analysis, a reasonable strengthening scheme was proposed for the single-layer system with poor stability. The results will be of great help for further research on large steel cooling towers and provide guidance for actual engineering design of the structures.

The recent roadmap of SPIRE initiative includes the development of “new separation, extraction and pre-treatment technologies” as one of the “key actions” for boosting sustainability, enhancing the availability and quality of existing resources. Membrane condenser is an innovative technology that was recently investigated for the recovery of water vapor for waste gaseous streams, such as flue gas, biogas, cooling tower plumes, etc. Recently, it has been also proposed as pre-treatment unit for the reduction and control of contaminants in waste gaseous streams (SOx and NOx, VOCs, H2S, NH3, siloxanes, halides, particulates, organic pollutants). This perspective article reports recent progresses in the applications of the membrane condenser in the treatment of various gaseous streams for water recovery and contaminant control. After an overview of the operating principle, the membranes used, and the main results achieved, the work also proposes the role of this technology as pre-treatment stage to other separation technologies. The potentialities of the technology are also discussed aspiring to pave the way towards the development of an innovative technology where membrane condenser can cover a key role in redesigning the whole upgrading process.

This paper presents the condition assessment of reinforced concrete (RC) walls of induced draft cooling tower (IDCT) structure. The main focus is on the assessment of quality, integrity and long term durability of RC walls, with reference to rebar corrosion. Details of non-destructive testing (NDT) carried out to evaluate the prevailing condition of the IDCT structure are presented. Test results revealed that the RC wall, which is intended to be an enclosure/curtain wall to arrest the splashing of sea water fed to the IDCT, is found to be of poor quality and could not arrest the seepage/dampness from inner face to outer face of the wall. To arrive at an effective repair measure to arrest the seepage/dampness in RC walls, porous concrete panels are cast to simulate the poor quality of in-situ concrete of IDCT walls and also to explore and evaluate the effectiveness of different repair schemes. The best repair scheme for improving water tightness is established by conducting selected durability tests on the cores extracted from the repaired porous slab panels. As a pilot study, the identified repair methodology is implemented on the selected wall panels of IDCT structure and its efficacy for water tightness/impermeability is confirmed through visual observation and IRT image scanning.

Present work compares and optimizes the performance of cooling tower assisted cascaded and hybrid configurations of vapor compression-absorption integrated refrigeration system. Both the systems ar...

Wind loads are the predominant loads of all the various loading combinations in structural design of cooling towers. Existing wind loading codes have a basic single interference factor and a simplified two-dimensional static wind pressure distribution formula, and do not enable accurate structural safety/reliability evaluation under dynamic wind loads. Among the various Equivalent Static Wind Loadings (ESWLs), the reinforcement-area-based ESWL is selected in this study, and the extreme reinforcement area considering wind directionality effect and nonuniform circumferential wind pressure is expressed as the equivalent criterion of reinforcement area envelope. A structural safety evaluation method, based on this innovative cooling tower design criterion, is derived as the dynamic reinforcement area envelope concept. The effects of time-variant weighted internal forces and non-Gaussian peak factor for the reinforcement area envelope are considered. The reinforcement area envelopes are compared with those from three different codes based on traditional simplified ESWLs. Finally, the results show that the existing loading codes do not cover the effects of interference amplification for structural safety. An alternative framework based on the reinforcement area criterion of weighted dynamic interval forces and its extreme value envelope are proposed, which can optimize both the economy and the structural safety design of cooling towers.

The study addresses the development of a method for the optimal design of vacuum-evaporative heat pump plants (HPP) for a cooling system of technological equipment of the second circuit at a nuclear power plant (NPP) using modern methods of thermodynamic analysis and thermoeconomic optimization. We have proposed two circuits for inclusion of a vacuum-evaporative HPP into a cooling system of the second circuit at NPP. The first circuit implies the use of HPP in combination with an existing cooling tower. It makes it possible to cool water additionally from 30°C to 25°C after a cooling tower. Only HPP cools water to the required parameters in the second circuit. A thermodynamic model to forecast static characteristics of HPP has been developed. We analyzed thermodynamic properties of water as a refrigerant and evaluated their influence on mode parameters and energy efficiency of a vapor compression cycle. It was established that water fully complies with all environmental safety requirements for operation substances of heat pumps. Its use makes it possible to provide high energy performance of a cycle in comparison with synthetic refrigerants. The problematic aspects of water use include high temperature, which is characteristic of a vapor-water cycle at the end of the compression process. However, it is possible to level the influence of temperature on energy and operational parameters of a plant by using a two-section condenser with utilization of heat from vapor overheating. We selected rational circuit-cycle solutions for a vacuum-evaporative HPP using a graph-analytic apparatus for constructing C-curves. The rational circuit-cycle solutions ensure efficient operation of a plant for cooling of technological equipment of the second circuit at NPP. The system’s capital capacity has been estimated as well. We used modeling of thermohydraulic processes in a circulation circuit of a refrigerant, performed thermoeconomic optimization and determined mode-and-structural characteristics of a plant that correspond to the minimum of resulting costs during its operation.

Effects of wind-induced internal pressures on the cooling tower’s structural performances are as significant as those of wind-induced external pressures. However, comparing to wind-induced external pressures, limited research focuses on wind pressures on the internal surfaces of large cooling towers. To fill up the scientific void, numerical analyses, physical model tests, and analytical studies are undertaken in this article. It is demonstrated that the draught ventilation ratio (i.e. the total area of the openings on the stuffing layer divided by the area of the stuffing layer) is the dominant factor for wind-induced internal pressures on large cooling towers, and 15% draught ventilation ratio can be regarded as the most unfavorable case. Besides, it is revealed that the theoretical formulation of the internal pressure on a single-cell building with a dominant opening and background porosity proposed by some other researchers can be applied to the case of a cooling tower subjected to strong winds. Using the validated theoretical formulation, the geometry of a large cooling tower is optimized with regard to the most favorable wind-induced internal pressure. The findings of this article are helpful for improving the current Chinese Code that governs the design of cooling towers.

Refineries are increasingly compelled to play an imperative role in achieving sustainable management of water as mandated by sustainable development goals (SDGs). Existing optimization models lack the ability to addresses this challenge of obtaining optimal refinery water network configuration for problems of industrial scale due to difficulty in application of complex solution algorithms of mixed integer non-linear problem (MINLP) formulations to large dimensions. Therefore, the optimization formulation in this work exploits process engineering derived constraints to build an integrated superstructure, which results in a simplified non-linear problem (NLP), and thus reduces computational complexity. Further, to substantially minimize fresh water consumption, the proposed model incorporates novel features of a modern refinery complex viz. distributed effluent treatment plant based on total dissolved solids (TDS) levels in waste water, segregation of sour water treatment based on phenolics content in condensate stream, and minimizing cooling tower blowdown rates by optimizing the cycles of concentration in cooling tower operation. The formulation is demonstrated for optimal water routing and economic benefits of the proposed approach through a representative case study of a real refinery complex. Towards the goal of zero liquid discharge, an efficient new scheme of recycling treated water to the boiler feed water system and cooling tower make up water requirements in optimal ratios, has been suggested from the results of the proposed model. Sensitivity of water reallocation in optimal refinery water network with respect to crude quality and desalter performance is also presented through application of proposed optimization framework in the case studies.

Traditional research on environmental impacts of natural draft cooling tower in nuclear power plant is mainly based on Gaussian diffusion model or wind tunnel experiments. With the development of modern mainframe computers and turbulence models, CFD method is possible to use for simulating plume drift. CFD software, as it owns powerful computing ability, can simulate and display the plume drift more accurately. In this paper, data from the 1977 Chalk Point Dye Tracer prove CFD simulation to be effective. Also, this paper provides case study on Taohuajiang and Pengze inland nuclear power plants in China. In conclusion, CFD result conforms with the data from the Chalk Point experiment. Compared with SACTI model. As down-wind distance increases, SACTI results decreases faster than CFD. This paper provides a solution that in the lack of field data, CFD will be a powerful tool for assessing environment impacts.

For a hyperbolic steel-structure cooling tower, a single-layer reticulated shell system was designed. The static behaviors of the single-layer reticulated shell system were studied under different load combinations. By analyzing the stability of the system, a whole load-displacement curve of the structure was obtained, and a reasonable strengthening scheme was proposed. Taking the grid form and grid size as the optimization parameters, the single-layer reticulated shell system for a steel-structure cooling tower was optimized at heights of 90, 124, and 220 m. The static behaviors of the single-layer reticulated shell system with different parameters, including the quantity of steel, maximum displacement of the nodes, peak stress, and ultimate bearing capacity, were compared. The optimum grid form and grid size of the single-layer reticulated shell system under different heights were obtained.

The natural draft dry cooling tower (NDDCT) has been increasingly used for cooling in power generation in arid area. As crosswind affects the performance of a NDDCT in a complicated way, and the basic affecting mechanism is unclear, attempts have been made to improve the performance of a NDDCT based on limited experiences. This paper introduces a decoupled method to study the complicated crosswind effects on the inlet and outlet of a NDDCT separately by computational fluid dynamics (CFD) modeling and hot state experiments. Accordingly, the basic affecting mechanism of crosswind on the NDDCT performance is identified. Crosswind changes the inlet flow field of a NDDCT and induces mainstream vortices inside the tower, so as to degrade the ventilation. Besides, low crosswind deflects the upward plume at the outlet to further degrade the ventilation, while high crosswind induces the low pressure area at the outlet to reduce the ventilation degradation.

The load–response correlation method has been recognized by the wind engineering community as a useful equivalent static wind load calculation method for structural design of quasi-static structures against strong winds. However, it has been found that the load–response correlation method is less effective to non-linear systems and in situations where load processes are non-Gaussian, such as large cooling towers subjected to strong winds. To validate the applicability of the load–response correlation method to large cooling towers, an aero-elastic model has been designed for a 215-m-high cooling tower in this article, which can simultaneously produce wind loads and wind-induced displacements of the structure according to wind tunnel model tests. Using data measured on the aero-elastic model, the exact results of correlation coefficients between wind loads and structural responses are obtained and validated by a non-linear finite element analysis. By comparing the correlation coefficients measured on the scaled model to the results based on the load–response correlation calculation, it is found that the correlations are much stronger for the load–response correlation calculation than those for the exact wind tunnel measurement. The explanation for this observation is that the non-linearity of the real structure and the non-Gaussian feature of the actual wind loads can weaken the correlations between the wind loads and the structural responses.

Solar cooling provides an ideal coupling between solar energy and the need for cooling, since both reach their maximum during the summer. However, solar refrigeration technologies either have not been competitive or are in a preliminary stage of development. Photovoltaic (PV) driven compression chillers are the most promising and close to market solar solutions today in the case of small to medium units (i50 kW cooling) due to the tremendous decrease in the cost of PV modules. The main objective of this work is to improve the efficiency of a PV panel by cooling it on its upper face by water sliding and on its back side using a solar chimney. In addition, the system is used as heat sink of a water chiller working as a low scale cooling tower. The work developed consisted of adapting and testing a prototype, changing its mode of operation to overcome the limitations encountered in the first campaign of measures. Several tests were performed by modifying the water mass flow rate circulated to the nozzles (spray) and onto the PV upper surface (water film). For the test with a water flow rate in nozzles of 500 l/h and sliding 250 l/h the results show an average cooling of the panel of 15°C and an improvement in the electrical efficiency of the panel of about 10%. The modified system is still able to dissipate a thermal power of about 1500 W with a thermal efficiency exceeding 30% in summer conditions.

To relieve soil thermal accumulation and performance degradation over a long-time operation for ground source heat pump (GSHP) system in cooling-dominated area, a hybrid GSHP system with cooling tower (HGSHP) was proposed. The purpose of this paper is to study the performance and feasibility of HGSHP in Shanghai. Firstly, the simulation model of GSHP system for an office building was established by TRNSYS 17.0 and the reliability of simulation was validated by the measurement data. Then, one-year and ten-year variation of performance parameters of GSHP and HGSHP systems were calculated respectively and explored in depth. These results shown that, compared with GSHP system, the annual average electricity consumption of HGSHP system decreased by 6.40% and coefficient of performance (COP) increased by 7.12% during the first year of operation. Additionally, the outlet temperature of buried pipes was below 32 °C for HGSHP system during ten-year operation, while in GSHP system, the over-standard rate of outlet temperature of buried pipes could reach approximately 80% and soil temperature increased by 10.9 °C. These findings indicated that HGSHP system could provide a feasible solution for cooling and heating in hot summer and cold winter zones.

Crosswind is a significant concern for the design and operation of a natural draft cooling tower. The negative effects of crosswind on the thermal performance of natural draft cooling towers have been shown in many cases, for a variety of tower types. This paper presents a comprehensive review to synthesize the current research status in this field. At first, three common cooling tower research methods used to quantify the crosswind effect: full-scale/field measurements, lab-scale tests and CFD modelling, are reviewed and discussed. Then, based on the existing literature, the crosswind effect and its working mechanism on different types of natural draft cooling towers are summarized and discussed. Finally, the most current findings and solutions to address the crosswind issue are reported. The main advantages and disadvantages of each solution are presented and discussed. The information collected in this review paper could be a useful guidance for the design and optimization of natural draft cooling tower.

In order to evaluate the impact of ambient conditions on the performance of indirect dry cooling system quantitatively, an analytical model was established which combined the numerical simulation of thermo-flow performance of natural draft dry cooling tower and the thermodynamic analysis of water-steam system in a 660 MW thermal power generating unit. The model was verified by experimental results and practical operating data, respectively. Temperature and flow fields of cooling air, as well as the back pressure of turbine were obtained under various natural crosswind and ambient temperature conditions. Standard coal consumption rates were acquired accordingly. The results indicated that the back pressure and standard coal consumption rate increased with the ambient temperature and wind speed. The most additional 27.72 g/kWh of standard coal consumption rate can be caused by the natural crosswind and high ambient temperature for the investigated power generating unit. A sensitivity analysis was conducted and the results showed that the value of the standardized coefficients for natural crosswind speed and ambient temperature were 0.446 and 0.888, respectively. Therefore, though the natural crosswind could deteriorate the flow field of ambient air, the ambient temperature had a greater impact on the standard coal consumption rate.

This work describes the exergy analysis applied to a single effect LiBr - H 2 O refrigeration system working together with a flat-plate-collector array. The main objective was to properly match the refrigeration cycle and the heat source. I used the experimental data collected from a solar-assisted air-conditioning system operating in the Solar Energy Research Center (Ciesol). The system employs a flat-plate-collector array, a hot-water single-effect LiBr - H 2 O absorption chiller, a cooling tower, two hot storage tanks, an auxiliary heater, as well as two chilled water storage tanks. The findings demonstrate that, from the exergetic point of view, I can achieve best results by supplying the absorption chiller with water within a temperature range of 70 – 80 ° C supporting it with the action of the chilled water storage tanks. As a result of this analysis, I recognized that there is great optimization potential for the control system of the studied system. At the same time I have ensured a proper balance between the refrigeration cycle and the heat source, making the solar-assisted air-conditioning system less energy intensive and safeguarding environmental protection.

A natural draft hybrid cooling system (NDHCs), which combines the benefits both for wet cooling and dry cooling, is proposed for thermal power generation with insufficient and unsteady cooling water source. An iterative calculation method is developed based on the physico-mathematical models to predict the performance of this system. Taking a natural draft dry cooling tower (NDDCT) suitable for 300MW power plant as object, the effect of water distribution of the dry and wet sections is investigated in the final part. It can be concluded this reformed system can reach a more flexible operation mode for complex environmental conditions.

The consequences of water crisis in terms of political, social and environmental impacts have been motivated in this paper to recognize the hybrid wet/dry cooling systems of power plant in Iran. The existence of temperature constraints for consumers connected to the hybrid cooling tower, Space constraints for the construction of auxiliary system, devoting attention to high Net Present Value (NPV) of the project over the course of 25 years, Returning the appropriate capital, Optimal Design of air cooler and it's desirable performance over the course of a year were the reasons led to use of the genetic algorithm (GA) in this paper. The GA should optimize the design of the air cooler, according to that, at one functional point of a year, the lowest investment costs and the lowest cost of utilization in one year will happen. The cost of utilization in this project including: water consumption (makeup water of the cycle), fan power consumption (wet and dry block of hybrid cooling system), as well as chemical additives to water. The results illustrated that the proposed algorithm usage, applying a proper control system, taking into account the standards in the written code and determining the optimization intervals according to the manufacturer's data could conclude to the design of an air cooler, which can be constructed by inquiring from the manufacturing companies. The results also indicated that optimized design of hybrid cooling tower could reduce water consumption about 63% over the course of one year, return on investment by 5 years, develop NPV up to 40 M€ and enhance steam turbine power.

Cooling towers are part of industrial technical building services and one of the main drivers for water and energy demands in industry. For planning and operation, the management of cooling tower systems has to focus on several objectives from strategical, tactical and operational perspective. These objectives relate to operational reliability, energy and resource efficiency as well as impacts on health and environment. Due to dynamic interdependencies within connected production systems and with the local environment, cooling tower management can be regarded as a complex task. Thus, a software-based support for decision makers involved in cooling tower management is presented basing upon the new concept of cyber-physical production systems. Enabled by a systematic data acquisition procedure, this approach combines comprehensive methodologies using white-box and black-box models. For a thorough system analysis and performance prediction, three modules have been developed within the cyber system: The system inventory and monitoring module allows to monitor the dynamic cooling tower system behavior and to calculate key performance indicator related to its operational performance. In the simulation module, a white-box model is used to test different alternatives for operational improvements in terms of energy and water demands. By means of the data analytics module, a black-box approach is applied to predict the system behavior with high accuracy basing on historical data. The full potential of the concept comes to bear through a continuous and consistent data basis as well as the synergetic application of the methodologies. As result, the approach provides support for decision makers at every level of cooling tower management. The approach was successfully applied on an industrial cooling tower system in an automotive manufacturing plant located in Germany, proving the advantages of the complementary methodologies. Thereby, the simulation revealed significant reduction potentials of water demands (−7%) and energy demands (−27%) through adapted operational strategies. As a further result, dynamic energy demand profiles could be predicted with a high accuracy (R2 = 0.98) by using multivariate regression analyses.

Recirculating cooling water system is the most common practice used for rejection of waste heat to environment. The fresh cooling water is distributed directly without reuse via a heat exchanger networks in parallel configuration to provide cooling duties for hot process stream. Under this configuration, thewater returns to cooling tower with high heat capacity flow rate and low temperature. These conditions will lead to poor performance of cooling tower.In this paper, process integration approach based on Pinch analysis technique used to address energy efficiency issues in cooling water networks for retrofit design problem. The Demand-Composite Analysisis an analytical approach requiring no graphical procedures developed in this work to target simultaneously, prior to the detailed network design, the minimum heat capacity flow rate of fresh cooling water and the maximumtemperature of waste cooling water to maximize the efficiency of cooling tower.The key basis for this methodology is the conversion of the cooling duties to its equivalent demand and source pairs.Agraphical representation called Demand-Composite Curveis then generated to understand the targeting philosophy. To synthesize a network that achieves the target values, the construction ofTemperature Diagram is also proposed as a design methodology for maximum reuse of cooling water.A case study is treated to illustrate the practicability of this approach.

A local company generates electricity via combined cycle power plant using natural gas. After the steam turbine, the in-line working fluid needs to be liquefied by a condenser. A water cooling system which is comprised of a fan cooling tower is used. The tower is consisted of series of cooling fans. The fans are comprised of blades which are supported onto a hub by “U” shaped holders. These pieces frequently brake down disturbing the normal operation of the unit. The paper refers to the microscopic examination of the failed parts. Historical data was collected, the pieces were macroscopic examined, hardness measurements were carried out and chemical analysis was performed. The study involved a detailed examination of the microstructures and fracture morphologies of the specimens derived from the failed parts. Conclusions are presented related to the fracture mechanism and the type of fractures respectively. All of the blade holders on this analysis were totally break by low cycle fatigue. Usages of impropriate material, as well as design deficiency of the holders, are considered to be the main causes for the failure.

In this study, a dual-stage heat pump system has been designed to utilize the heat of the ground water and to benefit from the heat of this water. Groundwater, which has been heat-treated, is intended to be re-grounded by a second deep well. In this application, well water at a depth of 110 meters, will be used as energy source. Hot water production will be provided by using groundwater at 15 °C in the primary circuit of the heat pump. Groundwater, which is reduced to 10 °C by taking heat from the heat pump, will be passed over the heat exchanger and will be used as cooling energy source in the primary circuit of the cooling tower. This reduces the flow temperature of the cooling tower and the water flowing through the cooling tower; which will allow “free cooling”. In the first stage of the designed system, it was determined that natural gas energy consumption of 2,880,000 kWh / year could be achieved by using hot water at 55 C, which is produced by water heat pump, in process heating.In the second stage of the system, the water cooled in the heat pump will be withdrawn from the cooling tower temperature operating in the range of 28-32 C, to the range of 15-20 C. The cooling units connected to the tower are expected to have a 40% reduction in energy consumption which will lead total of 90.000 kWh / year energy savings. As a result; 470,000 TL / year cost savings will be achieved; thanks to heat pump application and 9.100 m3/year water savings as well as 580,400 kg /year CO2 emission reduction.

The column based hyperbolic reinforced concrete cooling towers are ecstatic in aesthetics, gigantic in nature and complex in geometry. The evolution of “Design and Constructions” of these towers have come long way in India and as on date, 141.0m height Panipat Natural Draught Cooling Towers are the tallest commissioned towers in the country. In the past, before the computer revolution, the analysis used to be done only for membrane forces in shell elements. However, as the towers grew in stature beyond 100.0 m height clubbed with infamous episode of Ferry Bridge cooling tower in UK emphasized the relevance of bending analysis coupled with membrane forces. Invariably it is found that the structural criticality in NDCTs is due to the wind induced dynamic forces, which compounds the complexity of the above analysis. The following aspects, the peculiar geometry, the real boundary conditions, stress, temperature and time dependent behaviour of constituent materials including composites, space-time dependent loads including random excitations, different types of behaviors, such as linear, dynamic stability, etc., of structure to be examined, make the Finite Element Analysis apt and natural choice for the NDCTs. In the paper followed, the complexity of wind induced forces and rationale behind the applications, the progression from membrane analysis to bending analysis, the simple practice of descretising Finite Element Model for NDCTs and finally the illustrations and discussions on FEA for Panipat NDCT, the tallest tower in India as on date is discussed in length.

International audience; Water and wastewater processing (cooling tower, heat exchanger, treatment, etc.) generate desirable or undesirable biofouling (mineral, organic, biological) which may affect equipment or process performances. Fouling magnitude and nature stand as critical parameters to be evaluated in-situ and on-line to control and optimize the operation (production, cleaning). A fouling sensor based on a Micro-Electro-Mechanical Systems (MEMS) structure generating a local in-situ periodic thermal excitation (PTR) was studied in order to quantify and qualify fouling. At lab scale, model deposit (PVC) were used to simulate fouling conditions. Limits of detection (LOD) and quantification (LOQ) under steady and periodic thermal regimes were compared. Transposition to industrial conditions was investigated at pilot plant scale. A continuous bioprocess (PropellaTM reactor) was fed with diluted wastewater under controlled operating condition (temperature, mixing rate, flow rates, residence time) in order to mimic realistic industrial conditions and to generate a complex biofouling over six weeks. Thermal diffusivity, capacitive and resistive components are extracted from thermal spectrum response and a final fouling factor is introduced. Results demonstrate the ability to quantify and qualify a complex biofouling with in-situ and on-line information.