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Nowadays increasing energy efficiency and introducing energy-saving technologies is a strategic task for all national economies. During various industrial processes a large amount of heat is released which is often utilized in cooling towers of various types or dissipated in the atmosphere. The paper presents a study of a two-stage ORC-installation with various working fluids of cascades which allows solving the problems of heat recovery at industrial enterprises effectively. The paper presents an analysis of the thermodynamic cycles of the primary and secondary circuits of a two-stage ORC plant for various working fluids, and also determines the thermodynamic parameters of the combined cycles of an ORC plant with different working fluids. Promising working fluids for the primary and secondary circuits of a two-stage ORC plant are proposed, the thermal efficiency of combined cycles is determined. [ABSTRACT FROM AUTHOR]

In past several years, due to technology advancements, the costs of variable speed drives have come down sharply allowing the widespread applications of variable speed devices in building air-conditioning systems. This article presents the case study on application level of variable speed drives to the components of the air-conditioning system (VAV system) installed in Vivekanand Lecture Theatre Complex (VLTC) at MNIT Jaipur, India. After incorporating the variable speed drives to the air conditioning system, the proposed case energy performance index has been compared with the standard energy performance indexes of Energy Conservation Building Codes 2017(ECBC, ECBC+ and Super ECBC), developed by the ministry of power and Bureau of Energy Efficiency(BEE), India. The study of Hartman research paper on variable speed chiller plants has been used to learn existing algorithm for developing new operating strategies. Simulations are performed on EnergyPlusV8.8.0 (an energy analysis simulation program) for more than dozens of cases by making the variable a single and multiple combinations of HVAC equipment (AHU, Cooling Tower, Chiller, Pumps). The results show that the application of variable speed drives improved the performance of the air conditioning system substantially. At an average, the energy consumption of all variable chiller plant decreased by 40-45% compared to a constant speed chiller plant. All-variable speed chiller plant operating strategies have been developed based on the tailored specific performance characteristics of variable speed chillers and the variable flow characteristics of condenser pumps and cooling towers. The specific component-wise energy performance improvement after the incorporation of variable drives and ECBC compliance check for the proposed case has been presented in this paper. [ABSTRACT FROM AUTHOR]

The paper considers the theoretical aspects and presents the results of modeling the evaporative cooling of water in the form of a film, drops, water jet in cooling towers with a polymer sprinkler consisting of a bundle of pipes of a staggered arrangement. The processes of movement of gas-liquid heat carriers in sprinklers with a staggered arrangement of elements in a bundle of pipes for determining the heat transfer and mass transfer coefficients are considered. [ABSTRACT FROM AUTHOR]

Indonesia has the largest geothermal potential in the world, recently Indonesia only utilizes 7% of their geothermal to generate electricity. To increase the electricity production, the development of new geothermal power plant is needed, also the optimization of existing geothermal power plant. There are several types of geothermal powerplant system, depends on steam condition and utilization. This paper aimed to analyze the heat loss occurred in geothermal powerplant system X, also compare the cooling system between direct contact condenser (DCC) and indirect contact condenser (ICC). The comparison study has been simulated by using ASPEN HYSIS software. The method used to analyze the heat loss was by calculating exergy in each stream, so that we can calculate the exergy destruction at each process equipment. The result shows that the turbine produced 60 MW of electricity and largest heat loss occur on cooling tower with percentage about 17.64% for ICC system and 18.41% for DCC. [ABSTRACT FROM AUTHOR]

This paper analyzes the performance of a water cooled chiller at various number of fan cooling tower under the constant cooling capacity. The nominal capacity of the water cooled chiller unit is 800.0 ton and the refrigerant is R-514A. The performance of the water cooled chiller system when using 6 fans with a COP of8.29 and a kW/TR value not exceeding the minimum value set under the ASHRAE standard of0.42. The largest energy consumption is generated when the system uses 3 fans which is 2513.58 kWh during the period of time the system is turned on (7 hours). While the lowest energy consumption is generated when the system uses 6 fans which is 2036.78 kWh during the period of time the system is turned on (7 hours). The percentage of energy consumption increase when using 6 fans to 5 fans by 12,78%, from 5 fans to 4 fans by 7.48 % and from 4 fans to 3 fans by I,79%. Based on the results of analysis of the use of fan cooling tower variations on the performance and energy consumption of water cooled chiller is best when using 6 fans. [ABSTRACT FROM AUTHOR]

The paper considers the theoretical aspects and presents the results of modeling the evaporative cooling of water in the form of a film, drops, water jet in cooling towers with a polymer sprinkler consisting of a bundle of pipes of a staggered arrangement. The processes of movement of gas-liquid heat carriers in sprinklers with a staggered arrangement of elements in a bundle of pipes for determining the heat transfer and mass transfer coefficients are considered. The results of studies of the efficiency of heat transfer and mass transfer obtained at an experimental installation in the air-water system are presented, which show that the intensity of evaporative cooling of water with a tubular nozzle is greater than in a hollow countercurrent apparatus, which is explained by greater air turbulence, an increase in the surface and contact time of phases, due to more intensive crushing of liquid droplets in a sprinkler with a staggered arrangement of pipes. For options for improving the operation of an industrial cooling tower and the energy efficiency of its operation, a mathematical model of the heat-mass transfer process of cooling water in a cooling tower has been developed. This mathematical model and its algorithmization contributes to the solution of the system equation of gas and liquid motion in the sprinkler of an evaporative cooling tower, taking into account the influence of the liquid phase, the coefficients of turbulent exchange, heat transfer, mass transfer and the balance ratios of the transferred mass, heat flow. They were used to select the calculation options for cooling tower sprinklers. It is established that the intensity of heat transfer and mass transfer processes during the interaction of gas and liquid flows in the apparatus with the nozzle and contact elements during the dispersion of the liquid phase depends on: - the location of the nozzle elements; - the degree of crushing of droplets in the dispersant zone and the inter-tube space; - the wettability of the contact elements of the sprinkler with liquid; - air velocity; - the amount of water consumption. Computer modeling of real installations and modes was carried out, and by comparing them with the data of an instrumental survey of cooling towers, the validity and reliability of the mathematical model were established. The dependences of the mass transfer coefficient, heat transfer and thermal efficiency on the air velocity, water flow, irrigation density and the dependence of the hydraulic resistance of the sprinkler on its height are presented. [ABSTRACT FROM AUTHOR]

A multitude of concrete-based structures are typically part of a light water reactor (LWR) plant to provide the foundation, support, shielding, and containment functions. Concrete has been used in the construction of nuclear power plants (NPPs) because of three primary properties; its low cost, structural strength, and ability to shield radiation. Examples of concrete structures important to the safety of LWR plants include the containment building, spent fuel pool, and cooling towers. This use has made concrete's long-term performance crucial for the safe operation of commercial NPPs. Extending reactor life to 60 years and beyond will likely increase susceptibility and severity of known forms of degradation. Additionally, new mechanisms of materials degradation are also possible. Specially designed and fabricated test specimens can provide realistic flaws that are similar to actual flaws in terms of how they interact with a particular Nondestructive Evaluation (NDE) technique. Artificial test blocks allow the isolation of certain testing problems as well as the variation of certain parameters. Because conditions in the laboratory are controlled, the number of unknown variables can be decreased, making it possible to focus on specific aspects, investigate them in detail, and gain further information on the capabilities and limitations of each method. To minimize artifacts caused by boundary effects, the dimensions of the specimens should not be too compact. In this paper, we apply the frequency banded Synthetic Aperture Focusing Technique (SAFT) technique to a 2.134 m x 2.134 m x 1.016 m concrete test specimen with twenty deliberately embedded defects. These twenty embedded defects simulate voids (honeycombs), delamination, and embedded organic construction debris. Using the time-frequency technique of wavelet packet decomposition and reconstruction, the spectral content of the signal can be divided into two resulting child nodes. The resulting two nodes can then also be divided into two child nodes with each child node containing half of the bandwidth (spectral content) of its parent node. This process can be repeated until the bandwidth of the child nodes is sufficiently small. Once the desired bandwidth has been obtained, the band limited signal can be analyzed using SAFT, enabling the visualization of reflectivity of a frequency band and that band's interaction with the contents of the concrete structure. This paper examines the benefits of using frequency banded SAFT. [ABSTRACT FROM AUTHOR]

The cooling tower has always been an essential part of power plants or any other industry where there is heat removal needed. In a cooling tower, the maximum amount of heat transfer takes place in the packing zone. Therefore, it becomes necessary to predict the change in temperature, the mass flow rate of water, and characteristics of air like the specific humidity, dry bulb temperature, the mass flow rate of air along the packing height. There has been a lot of literature to analyze the behavior of wet cooling tower, however simple methodology without any notational ambiguity is not available. This paper uses the Continuous Differential Air-Water Contactor (CDAWC) model to predict water temperature along the packing bed. The mathematical model has system of ordinary differential equations having four equations and a MATLAB script is written to solve these differential equations using fourth order Runge-Kutta method. Furthermore, a regression equation is developed in order to predict the mass transfer coefficient and its dependence on various factors is discussed. An induced draft wet cooling tower is used to generate experimental data. The total height of the tower was 2.65m and the cross-sectional area was 2.4964 square meters. The temperature variation along the packing was measured with the help of K-type thermocouples to monitor the quality of air that was passing through the wet cooling tower. This model can also be further extended to check the air quality leaving the tower for changes in condenser load. The results drawn from the MATLAB code are in good accordance with the experimental data collected from the wet cooling tower in laboratory. [ABSTRACT FROM AUTHOR]

Concentrating solar power (CSP) plants make use of the renewable and inexhaustible solar energy to produce electricity. Limited by the scarce water resources, CSP plants built in arid areas choose Natural Draft Dry Cooling Tower (NDDCT) to remove waste heat. However, NDDCT suffers from low efficiency in hot summer days. To resolve this problem, inlet air spray-cooling is introduced to improve the performance of NDDCT. The single most influential factor that limits those cooling systems process performance in long-term operation is fouling. This mini-review reviewed the currently available papers on fouling studies and summarized the research trends from the conclusions highlighted by researches. In the first part of this paper, the research progress focused on the studies on NDDCT and how the hybrid(wet/dry) cooling could improve the CSP plants performance. In the second part, the fouling impact on cooling tower is presented, including experimental, characterization and model studies. The water velocity, the temperature, the heated tube materials and the geometry of the heated surfaces are the dominant parameters that effect fouling mechanism. Further requirements are identified in this paper in order to develop a reliable understanding of fouling effect on the application of cooling towers. [ABSTRACT FROM AUTHOR]

The paper describes the characteristics of the evaporative cooling tower (ECT) of the third power unit of the Rostov NPP. The actual temperature of the circulating water at the power is determined. Actual temperature exceeds the design temperature by 5.27 C. During the visual inspection, the reasons for the temperature increase were identified: leaks through the butt joints of the pipelines, damage to the irrigation blocks and the uneven operation of the spray devices. Repair work did not solve the problem of limiting the electric power of the turbine unit. In this regard, a project was developed to modernize the power unit cooling system. [ABSTRACT FROM AUTHOR]

Fouling problems are of major concern to many industries using water and heat, especially in cooling processes. Once scale forms on a heat transfer surface, at least two major problems associated with the scale occur. The first problem is the deterioration of the heat transfer equipment performance due to the much lower thermal conductivity of scale compared to that of pipe materials. The second major problem is that a small change in the tube diameter substantially increases the pressure drop across the water piping system. The fouling for cooling towers in CSP plants is an influential factor on whether the equipment is performed or not. Beside the water cooling quality, the tube material surfaces are being allowed increasing attention to evaluating the fouling phenomena. Those parameters can in fact highly affect the performance of a cooling tower; hence, it is central to evaluate how the used heat exchanger tube materials will be impacted by fouling factors. Although fouling can have an impact on a cooling tower performance through various ways, including water flow, air/water temperatures, water quality, and tubes materials. In this paper, we are focusing our attention to the fouling scale and its effect on the overall heat transfer coefficient, heat transfer and fouling resistance of deposits fouling through a comparative study based on SEM images, X-ray diffraction analysis and experimental results of polymers and galvanized heat surface materials. In order to understand the fouling behavior, an apparatus scale unit of a hybrid cooling tower designed for CSP plants was installed in the Green Energy Park (GEP) research platform, located in Benguerir, Morocco, in the framework of the MinwaterCSP project (supported by EU H2020). In this scope, the fouling deposits on the polymer and galvanized steel tubes were investigated. [ABSTRACT FROM AUTHOR]

Reinforced concrete cooling towers of hyperbolic shell configuration find widespread application in utilities engaged in the production of electric power. In design of critical civil infrastructure of this type, it is imperative to consider all the possible loading conditions that the cooling tower may experience, an important loading condition in many countries is that of the earthquake excitation, whose influence on the integrity and stability of cooling towers is profound. Previous researches have shown that the columns supporting a cooling tower are sensitive to earthquake forces, as they are heavily loaded elements that do not possess high ductility, and understanding the behavior of columns under earthquake excitation is vital in structural design because they provide the load path for the self weight of the tower shell. This paper presents the results of a finite element investigation of a representative “dry” cooling tower, using realistic horizontal and vertical acceleration data obtained from the recent and widely-reported Tabas, Naghan and Bam earthquakes in Iran. The results of both linear and nonlinear analyses are reported in the paper, the locations of plastic hinges within the supporting columns are identified and the ramifications of the plastic hinges on the stability of the cooling tower are assessed. It is concluded that for the (typical) cooling tower configuration analyzed, the columns that are instrumental in providing a load path are influenced greatly by earthquake loading, and for the earthquake data used in this study the representative cooling tower would be rendered unstable and would collapse under the earthquake forces considered. [ABSTRACT FROM AUTHOR]

Concentrating Solar Power (CSP) plants are located in desert areas where the Direct Normal Irradiance (DNI) value is very high. Since water resource is scarcely available, mechanical draft cooing technology is commonly used, with power consumption of mechanical fans being approximately 2% of the total power generated. Today, there is only one solar power plant (Khi Solar One in South Africa) uses a condenser installed in a Natural Draft Cooling (NDC) tower that avoids the windage loss of water occurring in wet cooling towers. Although, Khi Solar One is a cavity receiver power tower, the receivers can be hung onto the NDC tower. This paper looks at a novel integration of a NDC tower into an external molten salt receiver of a solar power plant, which is one of a largest commercial molten salt tower in China, with 100MWe power capacity. In this configuration study , the NDC tower surrounds the concrete tower of the receiver concentrically. In this way, the receiver concrete tower is the central support of the NDC tower, which consists of cable networks that are fixed to the concrete tower and suspended at a certain height over the floor. The cable networks support the shell of the NDC tower. To perform a preliminary analysis of the behavior of this novel configuration, two cases of numerical simulation in three dimensional (3D) models have been solved using the commercial Computational Fluid Dynamics (CFD) code, ANSYS Fluent 6.3. The results show that the integration of the NDC tower into an external central receiver tower is feasible. Additionally, the total heat transfer rate is not reduced but slightly increases when the molten salt receiver is in operation because of the additional natural draft induced by the high temperature of the receiver. [ABSTRACT FROM AUTHOR]

The paper discusses a simplified model of a plume, which should serve as a basis for better comprehension of the events that occur after the outlet from the cooling towers and assessment of the systems for reduction of the plume (i.e. Moisture Recovery Systems). From the results of the simplified model, a method is derived for assessment of the size of the plume in relation to the parameters of the air leaving the cooling tower and ambient air. [ABSTRACT FROM AUTHOR]

Heat is one of the most energy forms emitted to atmosphere by industrial processes. Water is considered to be the best material to reduce heat energy since its available in nature in abundance and has the ability to absorb heat efficiently. Cooling towers are ideal alternatives to re-cool hot water instead of throwing it especially in places that lack natural water resources or when there are environmental precautions because water with high temperature would be harmful to the ecosystem when it recycled to natural resources such as rivers and lakes. Also, cooling towers considered economically feasible when using west water. This paper interests with hydraulic characteristics of a counter flow wet cooling tower which was investigated experimentally. The tower filled with splash packing with Zig-Zag pattern. Current study used treated waste water and focused fundamentally on the influence of air and water flow rates on hydraulic features of cooling tower for different access water temperatures. The dependency between pressure drop and the air and water flux was spotted. In this study, it found that within a certain ranges the pressure drop increases by 75% due to liquid flux and 70% due to air flux while pressure drop is not affected by changing temperature at all. Two empirical correlation had been founded for dry pressure drop (with R2=99.5%), and for wet pressure drop (with R2=98.13%). [ABSTRACT FROM AUTHOR]

In conventional pact type cooling tower, Fill is used to break the fluid (water) into small droplets in order to increase the heat transfer. But the fill should be periodically changed because of the fungus deposited over it. The fungus deposited over the fill will restrict the free flow of fluid (water) leads to poor heat transfer. A small modification of a conventional pact type cooling tower to a shower type cooling tower by removing the fill material and by rotating the feed nozzle 180 degrees in upward direction can increase the heat transfer zone by increasing the height of water flow. The present study investigates through a counter flow mathematical model with respect to height, difference in temperature, specific humidity, change in diameter of water droplets and change in enthalpy of air water mixture. The performance of a shower cooling tower is studied with conventional pact type cooling tower and effectiveness of both of them is evaluated. [ABSTRACT FROM AUTHOR]

Cooling towers is one of the most important unit in industry, they are used to dispose heat from cooling media used in the integrated units. The choice of the cooling media plays recently an important rule due to fresh-water scarcity. The use of saline as a cooling media become of growing interest, but the corrosion problem has to be taken in consideration. In this study the simultaneous effect of cooling tower operation parameters on the corrosion rate of mildsteel is considered. The role of NaCl content is found to be pronounced more than the working solution temperature and flowrate. The corrosion of mild-steel in these studied factors had shown an interesting result especially with the NaCl% content. Firstly, there was an increase in the corrosion rate with increasing the salt content to 3.5% four times compared to that of 0%, but after a critical point (3.5%) the corrosion rate had been decreased to reach a level lower than that of pure water. While increasing the solution flowrate to 2.5 l/min and the temperature to 50ᴼC will increase the corrosion rate by 25 and 20% respectively. From the results, it is obvious that the high concentration (>10%) of NaCl will inhibit the corrosion rate of mild-steel significantly and this prologue the gate to the use of saline instead of fresh water without hesitation. [ABSTRACT FROM AUTHOR]

In the industrial world, the cooling tower is one of the tools used for cooling water circulation in industrial machinery. Inadequate cooling water can cause a machine, like a heat exchanger unit, to corrode or form scaling that will reduce effectiveness of the cooling tower system. This study aims to determine the effect of ozone performance and cooling tower water quality in a closed-type forced draft system - cross flow - indirect / closed. The method used in this research is to inject ozone 3gr / hr into the basin of the closed circuit system cooling tower and then conduct laboratory tests of AAS, Titrimetric, Gravimetric and Spectrophotometric. Value of evaporation loss showed 0:03 as the smallest value m³ / h and 0119 m³ / h as the largest. Ozone can be said to affect water quality in the closed circuit cooling tower system basin but ozone cannot be said to affect the performance for a period longer than 10 days. [ABSTRACT FROM AUTHOR]

Exergy analysis includes a psychrometric process, such as in the operations of the cooling tower. The total exergy can be split into both chemical and thermomechanical components, therefore enabling one to quantify the contribution of each term to the total exergy through the tower. The total exergy content of a material stream is calculated by summing up these above-mentioned exergies. The specific exergy in the psycrometric process - such as in the cooling tower operating mechanism without the effect of kinetic and potential exergy in a steady state. The minimum exergy destruction was in the top of the tower; it means at the top when the water is first entering the tower, the greatest heat and mass transfer from water to air occur. [ABSTRACT FROM AUTHOR]

This article discusses the possibilities in the area of modeling of the so called cooling tower plume emergent at operating evaporating cooling systems. As opposed to recent publication, this text focuses on the possibilities of a simplified analytic description of the whole problem where this description shall - in the future - form the base of a calculation algorithms enabling to simulate the efficiency of systems reducing this cooling tower plume. The procedure is based on the application of basic formula for the calculation of the velocity and concentration fields in the area above the cooling tower. These calculation is then used to determine the form and the total volume of the plume. Although this approach does not offer more exact results, it can provide a basic understanding of the impact of individual quantities relating to this problem. [ABSTRACT FROM AUTHOR]