Energy Tower Research Articles

Thermoeconomic analysis for hybrid solar Brayton cycles operating with different working fluids

A Brayton cycle analysis with regeneration fed by heat input from a central concentration solar energy tower and a combustion chamber that uses natural gas is presented. The thermodynamic model includes the irreversibility of the different components of a conventional Brayton cycle system and a solar concentration system through energy and exergy considerations. The environmental conditions of Barranquilla are used for the plant analysis using different working fluids throughout the day, where the carbon dioxide cycle presents an overall efficiency of 28.8 %, the cycle with air efficiency is 26.6 %, and the Helium cycle is 20.2 %. The model considers the energy flows within the plant and the exergy destruction. In this sense, the solar concentration system contributes an energy fraction of 0.209 when operating with air, while the exergy destruction fraction is 0.189 when operating with carbon dioxide when solar radiation is maximum. Finally, an estimation of the Levelized Cost of Energy is presented.

Operation Mode and Energy Consumption Analysis of a New Energy Tower and Ground Source-Coupled Heat Pump System

In order to solve the problems of performance degradation in energy tower heat pump (ETHP) systems under low temperature conditions and soil heat imbalances in ground source heat pump (GSHP) systems in cold regions, a new coupled system of ETHP and GSHP systems (the ET–GSHP system) and its operating mode were proposed. The mathematical model of the system was constructed along with the system’s form and operation scheme. The COP (coefficient of performance) and total energy consumption of the coupled system were then simulated and studied under a number of common operating situations. The heating season is divided into four periods based on varying outdoor ambient temperatures: the first period operates in series mode and has an average outdoor temperature of 2.38 °C; the second period operates in parallel mode and has an average outdoor temperature of −8.56 °C; the third period uses soil source heat pumps to operate separately; and the fourth period operates in series mode and has an average outdoor temperature of −11.32 °C. Operation of the coupled system in four periods was simulated and analyzed, and the operational efficiency and energy saving of the system were analyzed using an actual commercial building in a cold region as an example. The results demonstrate that the ET–GSHP system’s overall energy consumption during the heating period is reduced by 4.34% when compared to the traditional GSHP systems; the system’s COP can maintain a high level throughout the heating period, with an average COP of 3.315; and the soil temperature at the conclusion of the heating period is 25 °C, which is 8.89 °C higher than that of the traditional GSHP system, providing a guarantee of summer heat return. The new ET–GSHP system significantly boosts the efficiency of the system’s operation, achieves effective coupling between various heat sources through multi-stage control, and offers improved energy-saving advantages.

Downdraft energy tower for negative emissions: Analysis on methane removal and other co‐benefits

AbstractThe downdraft energy tower is proposed in research as a new technology for green electricity in recent years. In this work, it is analyzed as an emerging greenhouse gas removal technology against climate change that provides multiple co‐benefits for the environment, in addition to green electricity. Compared to other negative emission technologies, DET might be able to remove atmospheric methane (CH4) without adding additional equipment, materials or costs. In multiple case studies, the DET offers at least 15% increase in profit thanks to CH4 removal in addition to green electricity generation. © 2023 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.

First case of robot-assisted radical cystectomy and intracorporeal neobladder reconstruction with the Hugo RAS system: step-by-step surgical setup and technique.

Robotic assisted radical cystectomy (RARC) is a standard option for the treatment of bladder cancer. Currently, novel platforms are entering the market and the Hugo RAS (Medtronic, Minneapolis, MN, USA) is a new system consisting of an open console with 3D-HD screen and a multi-modular fashion. Even if several series are already available for radical prostatectomy, to now a full description of RARC performed with Hugo RAS is still lacking. We report the first case of RARC with intracorporeal neobladder performed with the Hugo RAS-and another case of RARC with ureterostomy. Both patients were affected by MIBC. Case 1 was a 61-year-old patient without comorbidities (CCI 4), in which a Bordeaux ileal neobladder was scheduled after previous NAC. The second was the case of a 70-year-old one with CCI 7 and BMI 35; in this case, a ureterostomy was planned. Details of the robotic system: one 11mm endoscope port was placed on the midline 2cm above the umbilicus. Another two 8mm robotic ports were symmetrically placed under vision on a transversal line-located 1cm below the umbilicus. A third robotic port was positioned on the left side in a W configuration. All ports were located at least 9cm between each other. Finally, two assistant ports were positioned in the right abdominal site. All arm-carts were parked 45-60cm from the operative bed, before the docking process begins. Three arm-carts were parked on the left side, the assistant and the scrub nurse worked on the right side, while the energy tower stayed at the foot of the bed, according to the previous description of Hugo RAS robotic radical prostatectomy. The endoscope arm-cart is docked first, then the adjacent left carts are docked; finally, the surgeon's right-hand cart is docked from the right side of the bed. The docking angles and tilt we applied were: endoscope: 175°; minus 45°; surgeon left hand 140°; minus 30°; surgeon right hand 225°; minus 30°; fourth arm 125°; plus 15°. The instruments we used were those fitting our conventional four-instrument setup for RARC: monopolar shears, Maryland forceps, needle driver and Cadiere as the fourth arm. The procedures were completed without technical errors or technological failures-requiring a change in surgical strategy. Docking time was approximately 35min; console time up to urethral dissection was 150 and 140min in Case 1 and 2. The time for pelvic nodal dissection was approximately 37min for both. The multi-modularity fashion of the Hugo RAS allowed an easy management of the bowel in Case 1; the absence of robotic staplers required the use of the laparoscopic ones, managed by an adjunctive assistant with room within the cart. In conclusion, RARC with the Hugo RAS is a feasible procedure able to reproduce all surgical steps without critical errors or complications requiring a change in surgical planning. Urinary diversion with intracorporeal reconstruction is feasible as well, with adequate preliminary outcomes.

Experimental assessment of energy tower's performance: evaluation of the impacts of solar radiation, humidity, and chimney's height on the overall efficiency.

Solar energy is one of the most feasible options to produce energy in countries where unexploited desert areas or solar radiation are abundant. An energy tower is an effective system for electrical power generation that can perform more efficiently along with solar radiation. As the primary aim of the present study, effects of different environmental parameters on total efficacy of energy tower were investigated. In this study, the efficiency of the energy tower system is investigated experimentally by an indoor fully adjustable apparatus. In this regard, a comprehensive set of influencing parameters like air velocity, humidity, and temperature and the effects of tower height on the performance of the energy tower are individually assessed. It is demonstrated that there is a direct relationship between an increase in humidity percentage of the surrounding and performance of energy tower, meaning that a 274% increase in humidification rate led to 43% elevation in airflow velocity. The kinetic energy increases in the direction of airflow from top to bottom, and as the height of the tower lengthens, the kinetic energy enhances and subsequently increases the overall efficiency of the tower. An elevation about 2.7% in airflow velocity was seen due to an increase from 180 to 250cm in chimney height. Although the energy tower performs efficiently in the nighttime, airflow velocity increases averagely about 8% during the daytime and at the peak of the solar radiation, the airflow velocity enhances by 58% compared to nighttime.

Heat transfer and mechanical characteristics of the absorber in solar photo-thermal power generation system

In order to solve the problems of thermal fatigue, high temperature gasification and low temperature solidification of the heat receiver, a numerical calculation model for the heat transfer function of the tower type solar thermal power gener?ation high temperature receiver is proposed. A perfect analysis method is used for the simulation, and a thermal simulation program for predicting the heat gain of the solar thermal energy tower is compiled. In this paper, considering the various field connection characteristics, numerical value and distribution of convective heat transfer coefficient of the heat absorption medium, the temperature of the outer wall of the heat pipe absorption, and the thermal image conversion work in a non-uniform heat flow boundary area of a model of heat receiver was studied. The experiments show that when the flow rate of molten salt in the tube increases from 1 m/s to 2 m/s, the heat collection efficiency of the heat collection increases rapid?ly, while the flow time is more 3 m/s, the heat collection efficiency increases more gradually. The efficiency of heat absorption of the heat receiver is in the middle of the heat receiver, which can achieve 88 of the thermal image conversion. In the same large enough value, the heat collected at the inlet and outlet of the heat sink is about 82. It is clear that the numerical simulation provides a reliable basis for the design engineering, and provide guidance for the design of a full control model of tower solar photovoltaic power generation.

Design and analysis of solar assisted mini desalination plant using waste humid air of energy tower suitable for small community

ABSTRACT The aim of this work is to design and analyze solar humidification and dehumidification desalination plant that is integrated with an energy tower. The proposed integrated water production plant (IWPP) utilizes the waste humid air of the energy tower for the production of potable water as an added benefit in bonus apart from the power production through energy tower. The layout of the proposed desalination plant has been presented which is configured with 100 solar humidification dehumidification desalination units and capable to fulfill potable water demand of 800 liters per day that may be sufficient for a small community of remote area. The seasonal and annual performance of the plant has been analyzed in the climatic condition of Jamnagar which is hot and humid city in western Indian state, Gujarat. The optimum values of air and water mass flow rate have been identified with the help of mathematical simulations in summer, rainy and winter season. The results showed that air mass flow rate 118–120 kg/hr through solar air heater is suitable for water production throughout the year. The water mass flow rate of 125–130 kg/hr in humidifier and 120 kg/hr−122 kg/hr in dehumidifier has been found optimum for potable water production. The seasonal variation in gain output ratio is 0.32−0.45 however it can be increased to 0.62 at optimized operating condition. Finally, the economic and environmental analysis of the proposed plant resulted Rs 0.93/kg (US $ 0.011/kg) cost of potable water, payback period of 0.49 year and 146.8 t/annum reduction in CO2 emission, respectively.

Simulation Experiment on Energy Tower Coupled with Buried Pipe System of Ground-source Heat Pump for Cross-season Heat Storage

It is proposed to use energy tower instead of solar collector system to store heat for buried pipe system of ground-source heat pump in summer, so as to solve the problem that soil temperature is too low due to unbalanced cold and heat load of GSHP in cold and severe cold area. The simulation results show that the thermal storage power of energy tower is affected by soil temperature and environmental temperature. The lower the soil temperature, the better the thermal storage effect of energy tower system for soil. The thermal storage power and environmental temperature change in a positive relationship. It is proved that the application of cross-season heat storage is feasible for energy tower coupled with buried pipe system of ground-source heat pump in cold and severe cold area.

Parametric Study of the Effective parameters on the Performance of Solar Chimney Power Plant

The solar chimney power plant (SCPP) is an effective option for electrical energy production from solar energy. In this paper, a numerical model to predict the SCPP performance is developed. The effects of collector angle and solar radiation are investigated on the parameters of air as the velocity and temperature. The study shows that when the collector angle is 20°, the velocity maximum is 1.8 m/s at the chimney base and the maximum temperature is 332.1k. in addition, increased solar radiation produces an increase in temperature (from 400 w/m² to 900 w/m²) and air velocity (from 22.25 m/s to 2.75 m/s) in the solar energy tower

Seasonal and Multi-Seasonal Energy Storage by Power-to-Methane Technology

The time-range of applicability of various energy-storage technologies are limited by self-discharge and other inevitable losses. While batteries and hydrogen are useful for storage in a time-span ranging from hours to several days or even weeks, for seasonal or multi-seasonal storage, only some traditional and quite costly methods can be used (like pumped-storage plants, Compressed Air Energy Storage or energy tower). In this paper, we aim to show that while the efficiency of energy recovery of Power-to-Methane technology is lower than for several other methods, due to the low self-discharge and negligible standby losses, it can be a suitable and cost-effective solution for seasonal and multi-seasonal energy storage.

Roadside vertical solar-wind energy tower

Fossil fuels and Nuclear power is responsible for about 82% of the current Energy Production in the US. While a small part is still being met by renewable energy sources, engineers are working hard on finding new sources of Energy. Another approach to the global clean energy crisis is that instead of looking for a new energy source, we should become Energy Efficient. Road power generation is a new technology where the wasted energy of a moving vehicle can be extracted and converted to useful work done. This paper presents such a technology which when employed at the corner of a road can send power directly to the grid or run streetlights depending on the mode of operation. This is done by constructing a Savonius Wind Turbine and then converting the wasted wind energy produced by a moving vehicle. In addition, a solar panel can also be placed on the top of the turbine and produce more energy. A microcontroller decides how Energy is to be sent to the grid or stored to be used for street lighting load. While the power production may vary depending on the traffic and conditions of the city, the S-rotor and solar panel have a maximum voltage of 19.1 V and 19.65 V respectively.

Design and Implementation of Hybrid Solar Wind Energy Tower

The proposed method might be a possible key to the combination of high levels of radiation by solar energy and speed of the wind on a monthly average basis. Wind Energy Tower (WET) and Hybrid Solar (HS) is combined to form the HSWET system and the function of solar panel in parallel with wind turbines thereby acquiring a higher total of renewable energy values. It is essential to measure the output power and monitor it regularly. And also the design of HSWET was being paralleled with an prevailing solar hybrid system have made changes from a single solar panel to a tree like structure which includes for solar panel to get more output power than before and the results of the proposed Hybrid Solar and Wind Energy Tower system resulted in a greater efficiency.

An Overview of Offshore Wind Energy Tower Designs

An overview of the global status of offshore wind energy, its scope in India and a review of the literature on the investigations on the dynamic behaviour of offshore wind towers is presented. Efficient use of offshore wind energy is required for the sustainable development of a nation. For achieving a reliable offshore wind tower, research and testing play an important role. Since in the offshore environment, additional loading and additional dynamic behaviour are to be considered, coupled dynamic analysis of offshore wind tower is significant. Various studies carried out on offshore wind tower led to the development of various numerical tools for the coupled dynamic analysis. This paper presents a review of various design concepts, coupled dynamic analysis and wave tank model testing of offshore wind towers.

Compliance and damping of piles for wind tower foundation in non-homogeneous soils by the finite-element boundary-element method

A combined finite-element boundary-element method for the dynamic interaction of the soil with flexible structures such as single piles or complete wind energy towers has been developed. Flexible piles in different soils are analysed in frequency domain. The different parameters such as the stiffness of the soil, the bending stiffness and the radius of the hollow pile are analysed for their influence on the complex compliances. The results have been determined as specific power laws which are different for the different load cases (horizontal, rocking, coupling) and for the different soil models (Winkler, continuum with constant, root-parabolic and proportional-linear stiffness variation). The strongest influence of the soil stiffness can be found for the homogeneous soil and the horizontal component. Winkler soils have a weaker influence than the corresponding continuous soils. An offshore wind energy tower has been modeled and calculated for wind and wave loads.

Aerodynamic properties of Wind Turbine Towers based on Wind Tunnel Experiments

The presented investigations aim to suggest more realistic models to predict the dynamic behavior of wind turbine structures. Two key issues are addressed: the aerodynamic damping and the cross-wind vibrations.Based on experimental studies in the boundary layer wind tunnel, aerodynamic information for both effects has been obtained. A scaled model of a wind energy tower (1:150) in combination with complementary models have been tested in a test bench designed to carry out HFFB, dynamic wind pressure and forced-oscillation experiments. Reynolds number based scale effects on the tower model have been studied previously.In the predictions of cross-wind vibrations, the length related correlation of vortices shedding from cylindrical structures plays an important role. Therefore, wind dynamic pressures were measured along static tower and cylinder models using pressure taps to determine realistic values of the vortex shedding correlation length.Motion-induced wind vibrations can be significantly influenced by the aerodynamic damping. Using the forced-oscillations method, experiments have been performed under controlled system oscillation with varying wind speed in prism models and tower model. The measured base model forces were correlated with the model motion using spectral methods to obtain the corresponding aerodynamic stiffness and damping coefficients.Both aerodynamic studies will allow more detailed models for the design of new wind tower structures. The acquired information will be applicable in MB-simulations to obtain more realistic and accurate wind turbine performances

Numerical and monitoring based Markov Chain approaches for the fatigue life prediction of concrete structures

The design of special concrete structures, such as foundations for offshore wind turbines, has to be carried out against complex requirements and under challenging environmental conditions. Among these are for example dynamic and cyclic loadings caused by wind and sea waves. Concrete fatigue processes are dominant degradation processes (a) that determine the technical lifetime of such foundations, and (b) that are difficult to determine in occurrence, severity and with regard to the redistribution characteristics in the cross section or structure using classical inspection or monitoring programs. Semi-Markov Chain approaches, which are based on process sojourn time considerations, combined with smart monitoring sensor systems and advanced nonlinear Finite Element simulation methods, present very promising approaches for the realistic description of concrete fatigue processes and their redistribution characteristics and in consequence for the prediction of the remaining lifetime. The objectives of the current work are (a) to present a Semi-Markov Chain approach that is based on smart monitoring information and on advanced nonlinear Finite Element simulations for the realistic assessment and the prediction of concrete fatigue processes, and (b) to demonstrate the Semi-Markov Chain approach on an offshore wind energy tower concrete foundation in Cuxhaven. This work presents a further step toward developing a software tool that can be used to perform reliability assessments of aging concrete structures and to update their reliability with inspection and monitoring data.

Multifunctional Environmental Energy Tower: A Case Study of an Innovative System for Renewable Energy Exploitation

In a context of increasing interest in energy efficiency, the attention to the environmental quality is bringing the city of the future to be structured on energy smart grids for electricity, heat and natural gas production and distribution. The Multifunctional Environmental Energy Tower intends to be considered as a node in the future Smart Grid of the borough “Rome EUR”, to decrease the primary energy consumption from fossil fuels, to reduce greenhouse gas emissions and to maximize the energy production from renewable sources, as required by the European Union objectives at 2020. Renewable energy generation systems are integrated in a single vertically developed building, where energy is mainly produced from waste in integration with thermal and electrical energy storage systems, to create an intelligent tower combining and meeting together energy demand and supply.This integrated system allows to overcome some problems related to the renewable energy sources usage: their non-programmability, the land occupation and consumption, the social acceptance and the imbalances in the electricity grid. The designed building produces electricity for the grid, ensuring the air conditioning for Acea's company utilities and to feed the existing heating district network located in “Torrino-Mezzocammino” district within “Rome Eur” borough.The architectural components were designed to link the architectural view and the functional aspects, because its location within the roman roads net developing from the “Grande Raccordo Anulare” (GRA) the tower is configured as a totem of energy efficiency and technological innovation.

The Multifunctional Environmental Energy Tower: Carbon Footprint and Land Use Analysis of an Integrated Renewable Energy Plant

The Multifunctional Environmental Energy Tower (MEET) is a single, vertical, stand-alone renewable energy plant designed to decrease the primary energy consumption from fossil fuels, to reduce greenhouse gas emissions, to maximize the energy production from renewable sources available in place and to minimize land use. A feasibility case study was performed for the city of Rome, Italy. Several technologies are exploited and integrated in a single system, including a photovoltaic plant, a geothermal plant and a biomass digester for urban organic waste and sewage sludge. In the proposed configuration, the MEET could cover more than 11% of the electric power demand and up to 3% of the space heating demand of the surrounding urban area. An LCA analysis evaluates the environmental impact in a cradle-to-grave approach for two impact categories: global warming (carbon footprint) and land use (land occupation and land transformation). The functional unit is a mix of electric (49.1%) and thermal (50.9%) energy (kWhmix). The carbon footprint is 48.70 g CO2eq/kWhmix; the land transformation is 4.058 m2/GWhmix; and the land occupation is 969.3 m2y/GWhmix. With respect to other energy production technologies, the carbon footprint is lower and similar to the best-performing ones (e.g., co-generation from wood chips); both of the land use indicators are considerably smaller than the least-impacting technologies. A systematic study was finally performed, and possible optimizations of the original design are proposed. Thanks to the modular design, the conceptual idea can be easily applied to other urban and non-urban scenarios.

Entanglement spectroscopy of SU(2)-broken phases in two dimensions

In magnetically ordered systems the breaking of SU(2) symmetry in the thermodynamic limit is associated with the appearance of a special type of low-lying excitations in finite size energy spectra, the so called tower of states (TOS). In the present work we numerically demonstrate that there is a correspondence between the SU(2) tower of states and the lower part of the ground state entanglement spectrum (ES). Using state-of-the-art DMRG calculations, we examine the ES of the 2D antiferromagnetic J1-J2 Heisenberg model on both the triangular and kagom\'e lattice. At large ferromagnetic J2 the model exhibits a magnetically ordered ground state. Correspondingly, its ES contains a family of low-lying levels that are reminiscent of the energy tower of states. Their behavior (level counting, finite size scaling in the thermodynamic limit) sharply reflects tower of states features, and is characterized in terms of an effective entanglement Hamiltonian that we provide. At large system sizes TOS levels are divided from the rest by an entanglement gap. Our analysis suggests that (TOS) entanglement spectroscopy provides an alternative tool for detecting and characterizing SU(2)-broken phases using DMRG.

Power from the wind in South Africa

Three blades — each the length of a tennis court — revolve atop a wind energy tower reaching 50 metres into the sky, equal in height to a 17-storey building. There are four such turbines whirling in the hot, dry and windy landscape near the town of Darling in South Africa’s Western Cape, generating 7 gigawatt hours per year of green energy. This first commercial wind farm in South Africa, reflecting the collaborative efforts of international donors, government agencies and the private sector, shows that wind energy is feasible