Central Tower Research Articles

Water quality in the Chinese Qinling Mountains over the last 20 years

The Qinling Mountains, the so-called “central water tower,” are extremely important water resource hubs in China. The influence of the forest ecological environment on water quality is complicated. Therefore, to investigate the spatiotemporal variations in water quality, we employed a random forest model to integrate multiple key water quality indicators into one overall ranking value. Monthly monitoring data of surface runoff and atmospheric precipitation events (2003–2022) for the Huodigou stream in the Qinling Mountains were used. The results revealed that after atmospheric precipitation entered the forest ecosystem, the coefficients of variation of surface runoff for most of the selected indicators decreased, but there were significant differences among the six indicators (NO3−, Mg2+, Na+, pH, K+, Ca2+). Most of the indicators within surface runoff were positively correlated, such as those in atmospheric precipitation. However, some indices of surface runoff were negatively correlated with those of atmospheric precipitation, and there was a significant negative correlation between Ca2+ in atmospheric precipitation and Ca2+ in surface runoff and between NO3−in atmospheric precipitation and K+ and Na+ in surface runoff (p < 0.01). The water quality grade of the surface runoff generated by atmospheric precipitation through forest ecosystems was significantly improved (p < 0.001), among which the average water quality grade of surface runoff was approximately 3.6, that is, between Grade I-3 and Grade I-4, whereas the average water quality grade of atmospheric precipitation was approximately 4.5, that is, between Grade I-4 and Grade I-5. The order of improved water quality was NO3− > Mg2+ > Na+ > pH > K+ > Ca2+. Overall, our assessment revealed that from 2003 to 2022, the water quality grade in the Huodigou stream improved and was more stable. In summary, the forest ecosystem in the Huodigou stream has a significant water quality purification effect on the atmospheric precipitation it receives. Our novel criterion-based approach for categorizing the water quality of atmospheric precipitation and surface runoff offers a new tool for examining spatiotemporal stream water quality variations in the Qinling region and other mountainous areas.

Enhancing efficiency of dense array CPV receivers with controlled DC-DC converters and adaptive microfluidic cooling under non-uniform solar irradiance

Concentrating solar technologies offer substantial potential for optimizing solar energy for heat and power generation, particularly in green hydrogen production. This study investigates the use of commercial high efficiency concentrated photovoltaic (CPV) cells in a central tower concentrating solar system to enhance energy conversion efficiency. By integrating DC-DC converters with self-adaptive microfluidic cooling systems, we address current mismatches and temperature variations that affect CPV performance. The novel receiver design ensures scalability for large-scale implementations by implementing the electrical connections between DC-DC converters and each CPV cell without creating shaded areas. We numerically model and simulate the thermodynamic and electrical characteristics of a dense array CPV receiver, evaluating six illumination profiles. Our results indicate a significant improvement in receiver efficiency compared to the traditional configuration with bypass diodes, demonstrating an increase from 23.4 % to 30.3 % under a central Gaussian illumination profile, and reaching up to 38 % relative efficiency improvement depending on the applied profile. Power transfer losses decrease from 26 % to 10 % when 200 kW/m2 of illumination non-uniformity occurs. The proposed solution enhances reliability and energy conversion efficiency, presenting a viable path forward for large-scale CPV applications.

Variation of Heliostat Wind Loads in a Radial Field Array Model

The design of heliostats throughout a concentrated solar power (CSP) plant are currently of uniform design, however, research into the variation in heliostat wind loading within a radially staggered field array can provide insight into potential material cost savings in heliostat field design. Experimental investigation was carried out on a field array model in the University of Adelaide large wind tunnel. A total of 64 heliostat models of size 0.1 × 0.1 m were radially arranged over four surround rows. Four 3-axis load cells were utilized to analyze field array cases of morning (0700 hours), noon (1200 hours), and evening (1700 hours) configurations. Angle calculations for beam reflection were made for the 21st March (equinox). Results show mean and peak drag force coefficients reduce with distance into the field for a 1700 hour case due to high upstream blockage. Comparing the downstream drag and lift force coefficients against each test configuration, when heliostats are at steep elevation angles, high flow blockage leads to a reduction of coefficients downstream (0700 hour and 1700 hour cases). When elevation angles are reduced (1200 hours), drag and lift coefficients increase with distance from the central tower in the downstream direction. Results also show the central tower increases load coefficients on downstream heliostats, and therefore should be considered in heliostat wind loading and field design.

Developing Deformable Facets for Heliostats: An Increased Solar Concentration for Thermochemical Applications with Central Tower Receivers

In the present article a new design of a deformable facet and a heliostat with several deformable facets is presented. Previous work has been made around designing heliostats with concentrating facets in the facilities of the Plataforma Solar de Hermosillo. The evaluation and design process of facets and their evolution is also shown and reviewed. The facet design was initially conceived as a parabolic trough surface, however, through a modification of the facet, the surface was transformed into a concave surface. The resulting spot produced by the facet assumes nearly a spherical surface. A heliostat constructed with these facets shows similar optical performance with a previous one made with spherical facets; this spherical heliostat has a higher peak and mean flux. Nevertheless, the deformable facet heliostat presents a simpler construction and structure. A comparison between both heliostats will be presented.

Thermal Desalination Through Forward Osmosis Coupled With CO2-Mixture Power Cycles for CSP Applications

This work, performed in the framework of the H2020 EU project “DESOLINATION”, analyses the coupling between CSP plants using transcritical power cycles with CO2-mixtures and an innovative thermal desalination technique based on Forward Osmosis. Calculations are presented for a large scale CSP plant with central tower receiver and direct storage with solar salts in Dubai, adopting the mixtures CO2+SO2 and CO2+C6F6 in the power cycles. The heat rejected from the cycle condenser is recovered directly by the FO plant, where the draw solute is heated up from 40 °C to 76 °C, to allow for the regeneration of the draw solution used in the forward osmosis membrane. The thermo-responsive polymer adopted is PAGB2000, already considered in literature as a promising option. Results show a very effective synergy between the electricity and the freshwater production: high yearly solar to electric efficiencies are possible (around 19%), with a low freshwater specific thermal consumption (around 100 kWhth/m3). The proposed desalination method is more effective than a conventional MED system (with + 50% of yearly freshwater produced), while a larger solar field (+ 28% in surface area) is necessary for a PV+RO plant to produce annually both the energy and freshwater produced by the CSP+FO plants.

Landmarks to Lived experiences: A comparative study of Bahrain World Trade Center and Bahrain Bay Towers

The potential reverberation of urban development on the cityscape through its building functions and heightsgenerates a skyline, creating an aesthetic geographical pattern. Some have a tagline of being iconic, while others striveto attain it. The term 'iconic' is an emblem of expression, a mixture of traditional and contemporary design, and,foremost, the city's oldest superstructure. Bahrain has been fast progressing, exemplified by its wonderous skylinesand a blend from old to new. Bahrain World Trade Centre is one of its so-called 'iconic' and has won many awardsaround the globe for its sustainability aspect, while others are popping out of the datum, one of them is thecontemporary Bahrain Bay Towers, with a pride of being the tallest building in the skyline of Manama. This studyconducts pilot research comparing two superstructures, focusing on the perceptions and sensory experiences ofpeople living among them.

Penerapan Kompensasi Terhadap Korban Kejahatan Tindak Pidana Terorisme Studi Kasus Bom Bali

The bombing incident that occurred in Bali in 2002 was a tragedy that attracted world attention, with victims reaching 202 deaths and more than 200 people injured. This tragedy occurred after the hijacked plane crashed into the World Trade Center towers in America in 2001, which increasingly increased global attention to the issue of terrorism. The aim of this research is to examine compensation for victims of terrorist crimes. This research method uses a descriptive qualitative research method with a normative juridical approach using secondary data in the form of documents and books regarding the object of this research, then this research uses 3 types of legal materials in the form of primary legal materials, secondary legal materials and tertiary legal materials. The findings of this research show that in Law Number 31 of 2014 concerning Amendments to Law Number 13 of 2006 concerning Protection of Witnesses and Victims, victims of criminal acts of terrorism also receive protection for their personal security, family and property, and are free from threats. relating to testimony that will be, is being, or has been given and participating in the process of selecting and determining forms of security protection and support as well as providing information without pressure. Protection for victims of criminal acts of terrorism implemented in Indonesia is based on the 1945 Constitution of the Republic of Indonesia and Law Number 15 of 2003 concerning the Eradication of Criminal Acts of Terrorism. Bali bombing victims have the right to receive legal protection and compensation from the state for the acts of terrorism that occurred. They also receive protection for their personal security, family and property, and are free from threats related to the testimony they will, are giving, or have given.

IoT based Smart Fault Identification and Monitoring System for Electric Poles

Electricity is essential in modern life, but damaged power lines cause thousands of electrocutions in India every year. To fix a damaged power line, the power supply is turned off, and a fuse controller is placed on the electric feeder. If the fuse controller trips on a broken wire, the electricity is cut off until the damage is located. This process can be time-consuming and requires resources. This research aims to design a IoT based control system to reduce the time for repairing broken electrical lines and prevent accidents by adopting measures to expedite the repair process, enhance safety, and optimize maintenance efficiency. LoRa devices are installed every 1 km along the cable for a total range of 10 km. A central tower marks the halfway point. A single LoRa device at the tower may be more cost-effective than multiple devices at each pole. A control circuit embedded by transistor and diode safeguard the circuit's integrity and ensure current flows in a single direction, protecting it if a wire between two poles is damaged. After locating damage to a pole, an email is sent to the relevant authority, including location, pole number, and incident time. An automatic alarm will sound when electricity is turned off, warning the public of the danger. Additionally, this system saves time and resources, and is cost-effective.

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.

A Method for Projecting Cloud Shadows Onto a Central Receiver Field to Predict Receiver Damage

This work demonstrates methods of mapping high-spatial-resolution direct normal irradiance (DNI) data from satellites, Total Sky Imagers (TSIs), and analogous data sources onto a heliostat field for characterizing the spatial and temporal variation of the incident flux on a central receiver tower during cloud transient events. The mapping methods are incorporated into an optical software module that interfaces with CoPylot–SolarPILOT’s python API– to provide computationally efficient optical simulation of the heliostat field and the solar power tower. Eventually, this optical model will be incorporated into optimization models whereby a plant operator can understand the effects of cloud transient events on overall power production and receiver lifetime due to creep-fatigue damage and therefore make better informed decisions about receiver shutdown events. By more accurately modelling the effects of cloud events on receiver flux maps, this work may determine the magnitude and frequency of thermal cycling on receiver tubes and panels using actual or realistic cloud shapes instead of averaged DNI values–which may undercount the total cycle number. This work may also prevent unnecessary plant shutdowns due to overly precautionary control strategies and characterize the relative impact of various cloud types on receiver life. We plan to eventually integrate this methodology into the System Advisor Model (SAM) to improve performance model accuracy during periods of cloudiness. In this paper, we demonstrate generating DNI maps and mapping them to a solar field in CoPylot using 10 m resolution data from publicly available Sentinel-2 satellite data over the Crescent Dunes plant.

How much we know about precipitation climatology over Tianshan Mountains––the Central Asian water tower

Tianshan Mountains are the headwater regions for the central Asia rivers, providing water resources for ecological protection and economic development in semiarid regions. Due to scarce observations, the hydroclimatic characteristics of the Tianshan Mountains Precipitation (TMP) measured over highland (>1500 m) regions remain to be revealed. Here, we show the TMP belongs to a monsoon-like climate regime, with a distinct annual range and a high ratio of summer-to-yearly rainfall, and exhibits six abrupt changes, dividing the annual cycle into six precipitation sub-seasons. Over the past 60 years, the yearly TMP has significantly increased by 17.3%, with a dramatic increase in winter (135.7%). The TMP displays a significant 40-day climatological intra-seasonal oscillation (CISO) in summer. The TMP CISO’s wet phase results from the confrontation of the eastward propagating mid-tropospheric Balkhash Lake Low and the southward migrating Mongolian High. The sudden changes in the two climatological circulation systems trigger TMP’s changes, shaping the 40-day CISO. Emerging scientific issues are also discussed.

The behaviour of orthodox historic churches built with lime mortar in Romania consolidated with reinforced concrete after the 1977 earthquake

In Romania, historic monuments have suffered significant damage after earthquakes. In the southern part of Romania, in the Oltenia region between the years 1838 and 1977, five strong earthquakes with magnitude exceeding 7 ML occurred, causing severe and repeated damage to Orthodox churches constructed with brick masonry and lime mortar. After the 1940 earthquake, consolidation was carried out with modern materials for that period, such as metal ties and reinforced concrete. Due to the collapse of the central tower made of brick masonry during the 1977 earthquake in the Church of the Holy Archangels Michael and Gabriel in Craiova, it was reconstructed using reinforced concrete columns and beams. Furthermore, the consolidation was carried out using reinforced concrete. Due to the different mechanical properties of historic brick masonry with lime mortar and reinforced concrete, cracks appeared over time on the church walls in the contact zones between these materials. Under the coordination of Bishop Irineu of Oltenia, consolidation works were initiated for 17 historic monument churches in the Gorj region after the earthquakes in 2023, and this Church in Craiova was included in the list. The article presents the modes and areas of damage resulting from the introduction of consolidations with irreversible materials, together with the results of in situ tests conducted by the EXPIN laboratory in Padua, Italy, to determine the mechanical properties of the load-bearing elements comprising the Church and structural analysis of the Church using ETABS software to predict past, present, and future behaviour.

Central Tower Solar Receiver Structures: Construction and Performance Comparison”

The purpose of this study is to evaluate the design and thermal performance of various configurations of central tower solar receivers, with an emphasis on spiral tube receivers. Specifically, it addresses the challenges of cost-effectiveness and efficiency within Concentrating Solar Power (CSP) systems. Multiple designs are assessed using a combination of analytical models and computational fluid dynamics (CFD) tools to assess thermal efficiency, heat transfer, and convective losses. Spiral tube receivers demonstrate superior thermal characteristics across various metrics as a result of the grid independence tests. Additionally, we discuss the effects of various mass flow rates on the outlet temperatures of the heat transfer fluid (HTF), in order to improve solar energy capture and conversion by optimizing the receivers.

ARAB MUSLIM CHARACTERS IN KHADRA’S NOVEL THE SIRENS OF BAGHDAD

In this study, the researcher presented the American’s views of Islam and Muslims in Khadra’s Novel The Sirens of Baghdad. The image of Arab Muslim character is portrayed differently by the post-colonial novelists post September attacks 2001 on the World Trade Centre towers situated in New York City, USA. Since the accident, many American writers who represent the Western values have endeavored to stigmatize the picture of Arab Muslims through their writings using variant depictions to confirm their ‘Others’ as they consider the Arab Muslims their foes in the world. Consequently, the American writers perpetuate their previous negative picture to continue their domination upon the Arab Muslims, using post-colonial concepts in their portrayal. In contrast, the Arab writers try their best to depict the image of the Arab Muslim characters fairly as they have realistically witnessed and experienced the actual life events. Due to this, Orientalism, stereotyping, otherness and racism are the key concepts examined in this study related the Sirens of Baghdad. As many other Western and Arab writers have dealt with the same concepts previously, the current study examined and identified the concepts differently through this study concerning Arab Muslim characters from contrasting perspectives. Accordingly, the researcher adapted Said’s Orientalism theory as a main method of analysis. The research findings revealed that the American novelists purposely reflected dark aspects of the Arab Muslim characters so as to show to the world that Islam is a religion that propagates oppression and violence. On the other hand, the Arab novelists successfully and realistically proved that it is the Westerners who most of the time oppress the Arab Muslims and murder a fairly good number of them on the basis of false and unfounded allegations. As a conclusion, the study proposes a framework of the portrayal of the Arab Muslim characters conceptualized by the post-colonial perspective. It is recommended that future research examines the reliability and authentication of the respective American novels that have distorted the Arab Muslim identity by using high level of fictitious representations that is very distant from reality and truth, so that the negative representations of the Arab Muslim characters can righteously be repudiated. Moreover, future research can explore cross-cultural studies related to the novel concerned and the like of them so as to highlight the psychological, cultural and societal representations of the two nations—the Arab and
 the Western.

World Trade Center Exposure, DNA Methylation Changes, and Cancer: A Review of Current Evidence.

Introduction: Known carcinogens in the dust and fumes from the destruction of the World Trade Center (WTC) towers on 9 November 2001 included metals, asbestos, and organic pollutants, which have been shown to modify epigenetic status. Epigenome-wide association analyses (EWAS) using uniform (Illumina) methodology have identified novel epigenetic profiles of WTC exposure. Methods: We reviewed all published data, comparing differentially methylated gene profiles identified in the prior EWAS studies of WTC exposure. This included DNA methylation changes in blood-derived DNA from cases of cancer-free "Survivors" and those with breast cancer, as well as tissue-derived DNA from "Responders" with prostate cancer. Emerging molecular pathways related to the observed DNA methylation changes in WTC-exposed groups were explored and summarized. Results: WTC dust exposure appears to be associated with DNA methylation changes across the genome. Notably, WTC dust exposure appears to be associated with increased global DNA methylation; direct dysregulation of cancer genes and pathways, including inflammation and immune system dysregulation; and endocrine system disruption, as well as disruption of cholesterol homeostasis and lipid metabolism. Conclusion: WTC dust exposure appears to be associated with biologically meaningful DNA methylation changes, with implications for carcinogenesis and development of other chronic diseases.

Precise and fast spillage estimation for a central receiver tower based solar plant

An accurate and computationally cheap method to estimate the optical efficiency of a heliostat field associated with a central receiver tower (CRT) system is essential for an optimized design. In this article, an improved method is developed to estimate the intercept efficiency of a field with flat heliostats. Based on the slant distance, a judicious combination of two different schemes, i.e. Elliptical Gaussian Distribution (EGD) and Pseudo Ray Tracing (PRT), is employed to estimate flux in an image plane. The flux from the image plane is translated to the receiver to estimate spillage. The proposed method is rigorously validated against the state of the art tool, SolTRACE, under various conditions which demonstrates robustness and accuracy of the method. The deviation of intercept efficiency from SolTRACE is small (within 1.5 %). However, such a high degree of accuracy is achieved at a meagre computational cost (below 15 %) compared to SolTRACE even without parallel computing. Thus, the intercept efficiency or spillage estimation of a given heliostat field is rendered ten times faster by the method presented in the current article without a loss of accuracy. An earlier study by the same authors showed the accurate and fast estimation of shading and blocking efficiency. The present study adds to the previous effort and proceeds towards the objective of achieving a fast and precise tool for the design and analysis of heliostat fields. The proposed tool is developed in Python environment which exploits the parallel computing features based on NumPy, Pandas and multiprocessing.

Seismic control of a long-span triple-tower suspension bridge using hysteretic steel damper

The seismic performance of a long-span triple-tower suspension bridge is a critical consideration in engineering communities. To promote a better seismic design, this paper presents a parametric study on the structural seismic control using hysteretic steel dampers. The finite element model is firstly established, and an introduction to the mechanical properties of the E-shaped hysteretic steel damper is made. Then, a seismic analysis is conducted under uniform earthquake excitations. Considering the effect of wave passage, the performance of hysteretic steel dampers in seismic control is further analyzed. The results indicate that the travelling wave effect greatly affects seismic responses. Increasing the damper elastic stiffness can effectively reduce the relative displacement between the main girder and either the left or the central tower. This treatment is effective for the right tower only when the wave velocity is among 400–1600 m/s, while it makes little contribution in other ranges. At an arbitrary wave velocity, increasing the damper elastic stiffness would cause minor changes to the shear forces of side towers, while its influence on the central tower is significant. A reasonable damper design for the long-span triple-tower suspension bridge depends on an essential prior evaluation of the wave velocity based on soil conditions.

Trace and Major Element Concentrations in Cadaveric Lung Tissues from World Trade Center Health Registry Decedents and Community Controls.

Studies of the health impacts of the 11 September 2001 terrorist attacks on New York City's (NYC's) World Trade Center (WTC) towers have been hindered by imprecise estimates of exposure. We sought to identify potential biomarkers of WTC exposure by measuring trace and major metal concentrations in lung tissues from WTC-exposed individuals and less exposed community controls. We also investigated associations of lung tissue metal concentrations with self-reported exposure and respiratory symptoms. The primary analyses contrasted post-mortem lung tissue concentrations obtained from autopsies in 2007-2011 of 76 WTC Health Registry (WTCHR) enrollees with those of 55 community controls. Community controls were frequency-matched to WTCHR decedents by age at death, calendar quarter of death, gender, race, ethnicity and education and resided at death in NYC zip codes less impacted by WTC dust and fumes. We found WTCHR decedents to have significantly higher iron (Fe) lung tissue concentrations than community controls. Secondary analyses among WTCHR decedents adjusted for sex and age showed the log(molybdenum (Mo)) concentration to be significantly associated with non-rescue/recovery exposure. Post hoc analyses suggested that individuals whose death certificates listed usual occupation or industry as the Sanitation or Police Departments had elevated lung tissue Fe concentrations. Among WTCHR decedents, exposure to the WTC dust cloud was significantly associated with elevated lung tissue concentrations of titanium (Ti), chromium (Cr) and cadmium (Cd) in non-parametric univariable analyses but not in multivariable analyses adjusted for age and smoking status. Logistic regression adjusted for age and smoking status among WTCHR decedents showed one or more respiratory symptoms to be positively associated with log (arsenic (As)), log(manganese (Mn)) and log(cobalt (Co)) concentrations, while new-onset wheezing and sinus problems were negatively associated with log(Fe) concentration. Fe concentrations among individuals with wheezing, nonetheless, exceeded those in community controls. In conclusion, these data suggest that further research may be warranted to explore the utility as biomarkers of WTC exposure of Fe in particular and, to a lesser extent, Mo, Ti, Cr and Cd in digestions of lung tissue.

Operating performance of a Joule-Brayton pumped thermal energy storage system integrated with a concentrated solar power plant

The expected performance of an innovative Pumped Thermal Energy Storage (PTES) system based on a closed-loop Brayton-Joule cycle and integrated with a Concentrated Solar Power (CSP) plant are analysed in this study. The integrated PTES–CSP plant includes five machines (two compressors and three turbines), a central receiver tower system, three water coolers and three Thermal Energy Storage (TES) tanks, while argon and granite pebbles are chosen as working fluid and storage media, respectively. A sizing of the main components of the integrated plant has been firstly carried out for the design of an integrated PTES-CSP plant with a nominal net power of 5 MW and a nominal storage capacity of 6 equivalent hours of operation. Specific mathematical models have been developed in MATLAB-Simulink to simulate the PTES and CSP subsystem in different operating conditions, and to evaluate the thermocline profile evolution within the three storage tanks during/charging and discharging processes. A control strategy has finally been developed to determine the operating modes of the plant based on the grid service request, the solar availability, and the TES levels. The performance of the system during a summer and a winter day have been analysed considering the integration of the PTES subsystem in the Italian energy market for arbitrage. Results have demonstrated the technical feasibility of the hybridization of a PTES system with a CSP plant and the ability of the integrated system to participate to energy arbitrage, although a lower exergy roundtrip efficiency (about 54 %) has been observed with respect to the sole PTES system (about 60 %).

Spatial focussing of wave energy for improved power capture by an oscillating water column

The world’s oceans represent an abundant reserve of renewable energy. Wave power is a ubiquitous resource which is both temporarily and spatially consistent. This designates wave power as a particularly suitable energy resource for exploitation. Nevertheless, the development of wave energy technologies is lagging behind other renewable energy devices. Few grid-connected wave energy converters (WECs) have been constructed or deployed. The main barriers to the commercialisation of WECs is the relatively low energy conversion efficiencies that have been achieved, both with prototype devices, and with full scale installations.
 Many studies have been performed to augment the wave energy capture by WECs. Until now, investigations have predominantly focussed on modifying the device geometry (e.g. additional chambers in OWCs, varied buoy shapes for point absorbers etc.), or PTO systems to improve the energy yield. In this study, a novel approach is adopted, which demonstrates that significantly improved WEC performances can be achieved by manipulating the hydrodynamic wave field in the vicinity of the WEC to consolidate the wave energy. Few studies have been undertaken on methods to focus the linearly distributed wave energy at the WEC device. The concept of concentrating renewable energy resources for improved harvest is employed in other industries, for example, concentrated solar power plants utilize vast arrays of mirrors to consolidate the areally distributed solar energy to a central PTO tower. The present study demonstrates that wave energy can be focussed in an analogous manner.
 This research investigates the effectiveness of various geometry structures to reflect and focus the incident wave energy to point locations at which WEC devices can be positioned. To achieve this energy focussing effect, we install reflecting walls within a numerical wave tank to manipulate the hydrodynamic wave field. Three diverse wall configurations are examined (see Fig. 1). Initially, a straight wall is installed at an oblique angle to the incident waves. The waves are reflected from the wall and interact with propagating incident waves, forming a chequerboard type pattern on the free surface. Where the incident waves and reflected waves interact, a positive interference manifests which yields amplified free surface displacements, signifying energy concentration localisations. The second set of numerical experiments investigate wave focussing in the concave opening of a parabolic reflecting wall. Significantly augmented free surface displacement amplifications are observed at the parabolic wall focus. Finally, the study investigates wave focussing at the convex side of a double parabola wall. In this configuration, a complex reflecting wave field pattern emerges which may be particularly suitable for the installation of a WEC array. In each of the geometrical scenarios described, an oscillating water column (OWC) WEC is installed at the wave focussing position and its performance is analysed over a range of incident wave conditions. The performance of the OWC in each wave focussing case is compared with an equivalent OWC installed in open-seas conditions. In this manner, the effectiveness of the wall geometry in terms of the energy focussing and subsequent energy capture enhancement by the WEC is determined.