Introduction
Over the past several decades, the importance of locating the sources of renewable energy that do not lad to the further contamination of the environment and the exacerbation of pollution outcomes has become particularly high. The use of air turbines as one of the core methods of addressing the sustainable energy concern currently represents one of the most promising areas to explore (Chowdhury et al., 2018). By including the relevant tools, one can optimize the process of oscillating water column wave energy conversion, as well as analyze is outcomes more effectively.
A closer look at the current energy sector will show that the search for sustainable energy solutions has currently been trending. As a result, noticeable transformations have been occurring in it (Wang et al., 2020). Among the core trends, one should mention the introduction of innovative technologies and the emergence of new business models that support the specified solutions (Wang et al., 2020). For example, the focus on solar and wind-based energy sources have been examined quite meticulously recently (Hidayatno et al., 2019). Similarly, the introduction of transmission infrastructure as the basis for active international collaboration and the enhancement of the supply chain development has been observed to enhance partnership and cooperation (Chowdhury et al., 2018). Finally, the target sector has been demonstrating sustainable growth over the past couple of decades (Meng et al., 2018). The outlined trends indicate that the opportunities to optimize oscillating water column wave technology for sustainable energy retrieval and use is a possi8biltiy.
Ocean energy has been a subject of constant and arduous efforts of numerous green organizations. Specifically, the concept of ocean energy suggests that waves, which have been confirmed to contain concentrated energy obtained from the sub radiation, implies that the energy concealed in ocean waves can be elicited with the help of machines that can convert the energy of the waves into electricity as they collide with an obstacle, releasing energy onto specific equipment (Giorgi et al., 2020). Thus, opportunities for gaining cheap energy in ample amounts become viable, which is why the pursuit of ocean energy should be seen as lucrative and of high potential.
However, the process is fraught with several difficulties, the challenges associated with converting the energy in question into electricity that can be use to fuel households and industries being the key issue. Specifically, despite being quite numerous, the existing water energy converters (WECs) have several noticeable flaws. Currently, the following WEC types are the most common ones globally: oscillating water columns, attenuators, oscillating wave surges, rotating masses, and terminator overtoppings (Giorgi et al., 2020). The specified devices are limited by the scale at which they can perform; however, the oscillating water column (OWC) appears to hold the greatest potential.
Since maintaining sustainability in energy production and consumption remains a priority, OWC as the most effective tool has been deployed actively or energy collection. The subject matter is represented by a chamber in which oscillation of ocean water waves allows building up the kinetic energy that is afterward transformed into the potential one, allowing for the further use of the energy in question both by households and organizations (Kang et al., 2022). As waves continue to oscillate, causing the air in the chamber to move rapidly, creating high-velocity air and developing the airflow that is further converted to electricity (Kang et al., 2022). Therefore, while being relatively simple, the specified design allows maximizing the output compared to the initial energy input, facilitating a power takeoff. In turn, to reinforce the efficacy of the OWC performance, adjustments involving the shift from the traditional type of air turbines to the unidirectional air turbine (UA) turbine as the tool that will allow changing the overall performance of the framework should be regarded as a crucial change.
Literature Review
The Oscillating Water Column Wave energy converter (OWCWEC) can be defined as the device that allows transforming the kinetic energy of waves into the potential energy that can be further used for various industrial and household purposes. Specifically, the notion of OWCWEC implies the transformation of mechanical energy into kinetic one by means of air compression. In turn, the air compressed within the chamber enhances the performance of the UAT so that energy could be generated as a result (Ciappi et al., 2020). The outlined process is implemented in multiple settings, yet ocean shores are typically seen as the most common environment for performing the specified task (Ciappi et al., 2020). The main rationale behind the specified choice concerns the significantly more orderly pattern of wave formation within the target setting (Mohapatra and Sahoo, 2020). However, due to the necessity to generate green energy on a global scale, opportunities for integrating OWCWEC wherever possible have been sought (Mohapatra and Sahoo, 2020). Therefore, a study on the options for enhancing OWCWEC mechanism’s efficiency is likely to be particularly important for promoting sustainable retrieval and use of energy, both on industrial and community scales.
What is crucial to notice is that the very performance of the OWC approach hinges on the efficacy of the WEC as the main tool for obtaining energy from the water resource and transforming the kinetic energy of the ocean waves into the potential energy that can be used to power households and industries. Specifically, the power of the turbine determines the parameters such as the chamber pressure and the flow, which, in turn, will define the final output (Aiman et al., 2020). For this reason, selecting the turbine design that facilitates obtaining the maximum energy available, or, in other words, shows the greatest performance efficiency, should be regarded as a priority.
The functionality of the OWC WEC is based on the extent to which pressure can be distributed across the inner surface of the construction. As a rule, the larger the extent of pressure distribution, the more effective the OWC WEC’s performance is (Aiman et al., 2020). The specified property is defined by the fact that, in the specified circumstances, the internal free substance within the OWC WEC behaves in the manner that can be compared to that one of a piston (M’zoughi et al., 2020). Consequently, the described force can be utilized to transform the energy obtained from the process of wave collision with the surface in order to transform mechanical energy into kinetic one (Aiman et al., 2020). As a result, opportunities for obtaining energy are produced.
One could argue that comparing the OWC WEC structure to the performance of a pistol largely implies oversimplifying the unique framework of the model. However, the specified comparison allows understanding the very basis for the model to function properly, as well as recognizing the core factors affecting its performance. As a result, improving the model becomes a possibility. Specifically, representing the model in the described light, one will be able to pinpoint the opportunity with the integration of the UAT mechanism into the system. Specifically, the fact that the internal air volume within the chamber of the OWC WEC allows for the UAT to make the necessary motion and, therefore, contribute to the transformation of the mechanical energy into kinetic one (Aiman et al., 2020). Consequently, opportunities for powering industries and households with the help of the described model are created. In turn, studies show that selecting the turbine design that fits the WEC framework best and facilitates the most efficient output suggests that maximizing the extent of WOC performance leads to an improved management of the available resources and, therefore, the increased extent of energy obtained in the process.
Furthermore there are evident and undeniable indications that the increase in the volume and, particularly, the diameter of the turbine leads to a rise in the extent of its efficiency. Specifically, the range of power that the turbine can absorb from the WEC rises exponentially with the increase in volume, which implies that the current design of OWCWEC needs to be revisited to expand its scale. Thus, the level of the equipment’s efficacy can be increased substantially.
However, the use of UATs as the main means of obtaining energy from the OWC by subjecting it to the WEC mechanism is linked to several limitations. Specifically, research shows that the aerodynamic performance of the conventional flow turbines has been constrained to a significant extent by the limitations of the design thereof (Opoku et al., 2020). Furthermore, UATs do not allow for the introduction of self-rectifying properties, which represents another major obstacle to increasing the energy output and delivering the best performance possible (M’zoughi et al., 2020).
At the same time, one must mention the benefits associated with the introduction of self-rectifying turbines into the framework for maintaining the performance of a WEC in the OWC structure. Namely, studies reveal that the application of the self-rectifying turbines allows saving resources needed for maintaining the valve system in a pristine condition despite specified type of UAT has a rather low operational speed. Furthermore, the large number of details allows controlling the management process to a greater extent, thus leading to more accurate and precise results (Opoku et al., 2020). Therefore, the maintenance of the described turbine type may not necessarily compensate for the time and resources spent on rectifying turbines with the help of corresponding equipment, yet it provides essentially positive outcomes (Opoku et al., 2020). Nonetheless, the application of the UAT can be considered a benefit compared to the alternative option due to the presence of additional
At the same time, when considered alongside other types of turbines, including TI ones, UATs seem to be quite a beneficial choice. Specifically, the limitations associated with energy waste, as well as the extent of performance and diversity of available options, male the TI turbines a much more reasonable choice for producing ocean-based energy (Joensen et al., 2021). Thus, further reconsideration of the existing approach toward ocean energy production will be needed.
Additionally, different options for OWC should be considered as the means of ensuring that the efficacy of the system performance and, therefore, the percentage of energy obtained from the kinetic one supplied by waves remains consistently high. Specifically, the concept of the U-shaped OWC needs or be examined as a potential improvement to the current EWEC design. Among the key advantages that the proposed system has compared to the traditional OWC framework, one should not an increased speed of energy processing. Namely, studies reveal that the U-shaped framework can boast a greater eigenperiod when compared to the traditionally shaped OWWC (Joensen et al., 2021). Known as the period that describes a frequency of water oscillating without the presence of a damping force, the eigenperiod represents a vital characteristic of the system and needs to be expanded for it to function with greater efficacy (Trivedi et al., 2021). Thus, given its positive impact on the eigenperiod of the WOC process, the U-shaped OWC framework should be considered as an essential improvement in the quality and efficacy of the system performance. Particularly, additional opportunities for raising the amount of energy obtained from ocean waves emerge with the integration of the U-shaped OWC.
Furthermore, the effects of the UAT deployment in the target context needs to be examined in order to reach a conclusive statement concerning the use of the specified tool. Specifically, the UAT system introduces opportunities for a unidirectional rotation that facilitates the process of energy conversion from the kinetic wave energy to the e potential energy that can be utilized for multiple industrial and household purpose (Elatife and El Marjani, 2018). Furthermore, the use of the asymmetric rotor blades allows the UAT system to deliver a marginally positive performance. Specifically, the UAT-based approach allows minimizing the core costs, including the computational one, which are known for the dramatic effect on the quality of UAT maintenance, as well as the opportunity to maintain the device with the help of regular checks and updates. Therefore, the drop in the computational costs, among others, helps one to reduce the range of expenses, therefore, expanding the project budget (Elatif and El Marjani, 2018). For this reason, the integration of the UAT into the WOC system could be considered not only reasonable, but also necessary.
At the same time, the product in question has enough disadvantages to believe t to be slightly untrustworthy. The inevitable drop in the extent of performance should be mentioned. The refusal to continue the current policy is likely to lead to a disruption in the process of energy production and transformation, thus, affecting communities and industries. Consequently, the significance and urgency of changes to be introduced into the target environment must be recognized.
Therefore, compared to the bidirectional model, the UAT framework can be considered quite effective. Even though it can be characterized by the integration into the WOC system and is resulting implementation as the main method of energy collection, it still fails to create the premises where the process of energy retrieval and processing allows delivering the maximum possible output. for this reason, the current functioning of the WOC system with the UAT as the main method of energy extraction should be deemed as flawed and requiring an update. In turn, the inclusion of the UAT devices into the performance of the WOC system is likely to lead to an additional increase in value and performance. Specifically, studies confirm that the introduction of the tool in question into the framework of an EOC ssystem to improve the general output thereof, as well as the precession of the process.
At the same time, it is worth mentioning that the use of the UAT allows working with most of the conventional WOC systems due to the specifics of the UAT design. Indeed, research shows that the path for energy transformation that UATs suggest leads to substantially positive outcomes. Namely, the research by Doyle and Aggidis (2019) indicates that the application of UATs leads to particularly positive results for large-scale projects due to its comprehensive framework and the basic structure. However, the specified characteristic of the identified structure also suggests that it is unlikely to be helpful for small-scale models, where a broad range of factors must be considered (Doyle and Aggidis, 2019). In turn, the lack of complexity of the UAT tools leads to the failure to construct a small-scale model that represents the process fully and reflects all nuances of the energy retrieval process. Nevertheless, the observed issue can be considered solvable due to the opportunities to shift toward the use of different types of UAT. Specifically, direct-drive electrical UAT tools, as well as mechanical ones, are expected to contribute to an improvement in the performance of the system.
Finally, OWC can be optimized by enhancing the performance of the UAT system with the help of slight changes to its configuration. For instance, the current approach to setting the distance between some of the UAT parts, such as its guided vanes and the system of rotor blades, can be seen as quite effective for managing the OWC system. Namely, the unreasonably large gap between the two increases the extent of energy wasted in the process, thus, leading to a smaller output (Portillo et al., 2020). Consequently, the gap in question needs to be minimized to allow for an increased extent of the OWC capacity and the resulting rise in the output alongside a drop in the extent of production waste (Portillo et al., 2020). Overall, UATs prove to have a significant part in improving the performance of WO.
Furthermore, the specified tools allow controlling the volume more effectively, which is why nearly the entire space of the WOC system and the UA can be utilized to maximize the output and increase the extent of energy converted for the further use. Specifically, the combination of the half-submerged chamber design that the WOC system typically incorporates in its overall structure, and the core properties of the UATs help maximize internal air volume, thus, enhancing the turbine performance and raising the extent of energy conversion (Nabavi et al., 2019). The described improvement in the overall output of the system performance can be attributed to the simplicity of its design, which other options, such as the TI turbine, do not possess. Therefore, the application of the UATs to the process of energy conversion as the vital components of the process must be regarded as a major improvement in the performance of WOC. At the same time, the limitations of the UAT system should be acknowledged in order to transfer to a more cost-efficient and expeditious approach that reduces the levels of waste typically created in the process of managing the OWC wave energy systems.
Specifically, when considering the specified framework as the power take-off mechanism, one should mention several essential characteristics of the specified technology, as well as the requirements for power take-off. Namely, due to the high variability in the nature and properties of the ocean energy, the process of power take-off is likely to be exceptionally complex (Meng et al., 2018). Therefore, a framework that could help manage the high variability in the characteristics of the key energy resource while retaining a relatively simple structure is needed. In turn, the traditional system presents a set of characteristics that allow satisfying the specified requirement to an extent (Nabavi et al., 2019). Even though the issues such as elevation differences when it comes to the collection of kinetic energy and its further transformation creates certain constraints for the performance of UATs they still allow managing the challenge and transforming mechanical energy into kinetic one effectively. As Tetu (2017) confirms, “the surface elevation varies irregularly in time and can induce high amplitude displacements, accelerations and forces on a body in a very short period of time” (p. 204). Thus, the application of the UAT-based approach offers sufficient grounds for the retrieval of the energy (Tetu, 2017, p. 204). For this reason, the integration of UATs as the device for obtaining and transforming ocean energy should be considered as quite cost-effective. Admittedly, Tetu (2017) warn that harnessing ocean energy requires managing the issues associated with the inconsistency in the waves’ behavior: “the waves present low amplitude displacements, accelerations and forces” (p. 204). Consequently, an update in the existing framework is needed, which is why one should consider the integration of modifications to the current framework. However, the AUTs themselves as the deice for controlling and enhancing the OWC performance should be seen as instrumental.
Overall, the review of the existing studies on the issue of applying the UAT system to the process of retrieving energy from WOC proves that the alternative framework, while being substantially efficient, is quite flawed. Specifically, the limitations concerning its flexibility in relation to changes in waves’ properties and characteristics, as well as the overall performance quality and extent of the output, prove that the UAT framework is significantly superior.
Apart from the use of TI tubes, one should consider solutions involving a shift toward the use of a different WOC model. Specifically, the consideration of the U-shaped WOC should be regarded as a potential solution to the observed issue, specifically, low efficacy in obtaining energy and the lack of flexibility in adjusting to changes in the waves’ characteristics. Specifically, the model in question suggests that the device will remain functioning and efficient even when the motion of the fluid is not steady (Kushwah, 2021). Therefore, the integration of the U-shaped WOC helps address the current problem with the management of irregularities in the fluctuation of ocean waves, particularly, the frequency at which they hit the obstacle (Kushwah, 2021). As a result, the opportunities for keeping the process of energy retrieval and transformation consistent will remain possible, with the mechanical energy of the waves being converted to the kinetic energy that can be utilized to power both organizations and residential areas.
Additionally, one should consider the use of the Wave Swell Energy technology as the framework that will facilitate an improved management of the OWC WEC system. Implying high predictability and reliability, the specified framework should be deemed as the testament to the efficacy and significance of the UAT tool (King Island Council, n.d.). Therefore, the use of UAT should be encouraged as the main means of obtaining comparatively cheapen affordable energy.
Therefore, as a tool for power take-off for the OWCWEC, UAT can be regarded as functional and worthy of being deployed actively in the process of retrieving energy with the help of the WOC system. The current range of benefits associated with the integration of the specified tool into the OWCWEC framework include their short-term cost-efficiency and their uniform and quite simplistic design, which allows one to integrate them into virtually any context. In other words, the universal applicability of the tool in question represents the core advantage that is worth considering as the main selling point (Chowdhury et al., 2018). Although seemingly dismissible, especially when compared to what more advanced tools can offer, the universal applicability of UAT is not to be underestimated. specifically, given the increasing need for sustainable energy and the necessity to integrate relevant tools for obtaining it in as many contexts as possible, the ease in integration and use should be regarded as the key advantage of UAT (Rajapakse et al., 2018). Indeed, the current framework for incorporating UAT into energy production settings suggests comparatively feasible opportunities for managing the process of energy retrieval and its further transformation from mechanical into kinetic one (Gaebele et al., 2020). For this reason, continuing to use UAT in the OWCWEC context is highly desirable, even though an update of the existing system is strongly recommended.
Overall, one must admit that both TI tubes and UATs have their benefits and disadvantages when it comes to collecting energy from ocean waves and converting it to kinetic one. For this reason, the current framework involving the use of the UAT approach can be regarded as a possible solution as long as alterations to the very WOC structure are made. As the example above shows, the transformation of the WOC shape toward the one of the UAT framework allows reducing the extent of waste by channeling the waves in the manner that would allow for the maximum efficacy of energy transformation (Mishra et al., 2018). Therefore, the integration of the U-shaped WOC into the existing system must be considered as a necessary improvement that will lead to an increase in cost-efficiency of the structure and the improved outcomes in obtaining, and transforming energy.
Conclusion
Due to the limitations in the initial design of the previously used air turbine types, the use of the UAT mechanism should be seen as enhancing for the performance of OWC water energy converter which calls for the shift toward the enhancement of UAT use in the OWC energy retrieval. UATs enhancement should be considered an essential adjustment that will lead to an improved and more sustainable performance of the construction. Specifically, the incorporation of the UATs into the current model will allow amplifying the scale of the construction, particularly, the valve, thus, reducing the extent of energy consumed to support the performance of the equipment and the transformation of kinetic energy into potential one. For this reason, abandoning the current approach based on the use of multiple types of air turbines and replacing it with UATs should be seen as a positive change. Specifically, the proposed update in the management of ocean energy will allow increasing the output of the power take off mechanism, therefore, maximizing the extent of energy obtained as a result.
In other words, the performance of the OWC wave energy converter in the context of the unidirectional air turbines application has been quite impressive. Due to the crucial flaw in their design, the frameworks in question need to be revisited so that they could lead to a better management of the available resources and a more efficient transformation of the energy obtained from the ocean. Specifically, the costs of the produced energy, including the energy used for obtaining the one generated by the OWC, will have to be lowered, which can be implemented by changing the power takeoff mechanism. By switching from the traditional turbine types to a more cost-efficient and, therefore, substantially improved UAT turbine type, one will be able to facilitate the required change.
The significance of the specified alteration can be explained by the design of the roto. Specifically, the positioning of the blades, as well as the presence of a set of two ones instead of a single blade, allows for a more precise and much faster performance, therefore, maximizing the output and increasing the levels of performance for OC water converter. Consequently, the process of energy transformation occurs faster and with lower effort taken, which raises the productivity and minimizes costs.
Reference List
Aiman, M. J., Ismail, N. I., Saad, M. R., Imai, Y., Nagata, S., Samion, M. K. H., and Rahman, M. R. A. (2020) ‘Study on shape geometry of floating oscillating water column wave energy converter for low heave wave condition’, Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 70(2), pp. 124-134.
Chowdhury, J. I., Hu, Y., Haltas, I., Balta-Ozkan, N., and Varga, L. (2018) ‘Reducing industrial energy demand in the UK: A review of energy efficiency technologies and energy saving potential in selected sectors’, Renewable and Sustainable Energy Reviews, 94, pp. 1153-1178.
Ciappi, L., Cheli, L., Simonetti, I., Bianchini, A., Manfrida, G., and Cappietti, L. (2020) ‘Wave-to-wire model of an oscillating-water-column wave energy converter and its application to mediterranean energy hot-spots’, Energies, 13(21), p. 5582.
Doyle, S. and Aggidis, G. A. (2019) ‘Development of multi-oscillating water columns as wave energy converters’, Renewable and Sustainable Energy Reviews, 107, pp. 75-86.
Elatife, K., and El Marjani, A. (2018) ‘Optimization design procedure of a radial impulse turbine in OWC system’, International Energy Journal, 18(4), pp. 1-8.
Gaebele, D. T., Magana, M. E., Brekken, T. K., Henriques, J. C., Carrelhas, A. A., and Gato, L. M. (2020) ‘Second order sliding mode control of oscillating water column wave energy converters for power improvement’, IEEE Transactions on Sustainable Energy, 12(2), pp. 1151-1160.
Giorgi, G., Gomes, R. P., Bracco, G., and Mattiazzo, G. (2020) ‘The effect of mooring line parameters in inducing parametric resonance on the spar-buoy oscillating water column wave energy converter’, Journal of Marine Science and Engineering, 8(1), p. 29.
Hidayatno, A., Destyanto, A. R., and Hulu, C. A. (2019) ‘Industry 4.0 technology implementation impact to industrial sustainable energy in Indonesia: A model conceptualization’, Energy Procedia, 156, pp. 227-233.
Joensen, B., Bingham, H. B., Read, R. W., Nielsen, K., and Trevino, J. B. (2021) ‘Performance predictions of one-way energy capture by an oscillating water column device in Faroese waters’, In 14th European Wave and Tidal Energy Conference, EWTEC (Vol. 2021).
Kang, H. G., Lee, Y. H., Kim, C. J., and Kang, H. D. (2022) ‘Design optimization of a cross-flow air turbine for an oscillating water column wave energy converter’, Energies, 15(7), p. 2444.
King Island Council (n.d.) Note of planning application. KIC: Tasmania.
Kushwah, S. (2021) ‘An oscillating water column (OWC): the wave energy converter’, Journal of The Institution of Engineers (India): Series C, 102(5), pp. 1311-1317.
M’zoughi, F., Bouallegue, S., Garrido, A. J., Garrido, I., and Ayadi, M. (2020) ‘Water cycle algorithm–based airflow control for oscillating water column–based wave energy converters’, Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering, 234(1), pp. 118-133.
Meng, Y., Yang, Y., Chung, H., Lee, P. H., and Shao, C. (2018) ‘Enhancing sustainability and energy efficiency in smart factories: A review’, Sustainability, 10(12), pp. 4779.
Mishra, S. K., Purwar, S., and Kishor, N. (2018) ‘Maximizing output power in oscillating water column wave power plants: An optimization based MPPT algorithm’, Technologies, 6(1), p. 15.
Mohapatra, P. and Sahoo, T. (2020) ‘Hydrodynamic performance analysis of a shore fixed oscillating water column wave energy converter in the presence of bottom variations’, Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment, 234(1), pp. 37-47.
Nabavi, S. F., Farshidianfar, A., Afsharfard, A., and Khodaparast, H. H. (2019) ‘An ocean wave-based piezoelectric energy harvesting system using breaking wave force’, International Journal of Mechanical Sciences, 151, pp. 498-507.
Opoku, F., Atkinson, M., and Uddin, M. N. (2020) ‘Numerical investigation of an offshore oscillating water column’, American Journal of Mechanical Engineering, 8(3), pp. 88-105.
Portillo, J. C. C., Collins, K. M., Gomes, R. P. F., Henriques, J. C. C., Gato, L. M. C., Howey, B. D., and Falcão, A. F. O. (2020) ‘Wave energy converter physical model design and testing: The case of floating oscillating-water-columns’, Applied Energy, 278, pp. 1-11.
Rajapakse, G., Jayasinghe, S., Fleming, A. and Negnevitsky, M. (2018) ‘Grid integration and power smoothing of an oscillating water column wave energy converter’, Energies, 11(7), p. 1871.
Tetu, A. (2017) ‘Power take-off systems for WECs’, in Handbook of ocean wave energy (pp. 203-220). Springer, Cham.
Trivedi, K., Koley, S., and Panduranga, K. (2021) ‘Performance of an U-shaped oscillating water column wave energy converter device under oblique incident waves’, Fluids, 6(4), p. 137.
Wang, R. Q., Jiang, L., Wang, Y. D., and Roskilly, A. P. (2020) ‘Energy saving technologies and mass-thermal network optimization for decarbonized iron and steel industry: a review,’ Journal of Cleaner Production, 274, pp. 1-8.