Introduction[edit | edit source]
- Irrespective of reduction in the cost of solar PV panels, balance of systems (BoS) hasn't seen significant cost improvements.
- Racking constitutes a significant portion of capital expenditures for small-scale PV systems.
- Some projects have embraced the open-source paradigm within the photovoltaic (PV) domain, aiming to create PV racking system.[1]These systems utilize distributed manufacturing techniques to produce 3-D printed ground-mounted,[2] flat-roof,[3] and building-integrated PV (BIPV) racking[4] solutions from conventional PV modules. Additionally, they target RV roof racks for PV,[5] floating PV installations,[6] and utility-scale ground-based low-concentration solar electric systems.[7]
- However,the proprietary nature of most racking components has limited the exploration of PV racking systems.
- To address the issue of cost-effectiveness, 'tensegrity' structure is introduced in this literature, leveraging locally available hardware, and validated through numerical modeling.
- 'Tensegrity' is formed by merging 'tensional' and 'integrity,' signifying the structural integrity achieved through a combination of tension and compression elements.[8]
- It refers to a design principle where a structure achieves stability and strength through the balance of tension and compression elements.[9]
- The first prerequisite of this tensegrity is to get the deployable configurations of the structures.
- However, not all class and configuration of tensegrity structures qualify as deployable for all applications.
- In paper,[10] Arefeen, et al. evaluated a tensegrity structure as a supporting solution for solar PV arrays.
Planar Bridge Tensegrity Structure:
- The minimal-mass, optimal complexity theory confirms that for a Class-1 tensegrity structure, p = 1 is the optimal configuration, and the optimal value of n is obtained according to the material properties of the tensegrity members, the load properties, and the bridge span.[11]
- Planar bridge tensegrity structure does not have any supporting structure above the deck, making it ideal for the installation of solar panels directly on the deck.
Literature review on "Tensegrity based structures"[edit | edit source]
Deployable Tensegrity Reflectors for Small Satellites [12]
In 2002, A. G. Tibert and S. Pellegrino proposed a cost effective, small deployable tensegrity prism used as a reflector as an alternative for tall compact-packaged reflectors.
- Tensegrity prism: ring structure with two identical cable nets connected by tension ties and a reflecting mesh attached to the front net.
- Fulfilled specifications for a small satellite mission, necessitating a 3-meter aperture operating at 10 GHz, while maintaining a height of less than 0.8 meters.
Designing tensegrity modules for pedestrian bridges[13]
In 2010, Landolf Rhode-Barbarigos, et. al explored the design of a pedestrian bridge based on tensegrity principles.
- Structural viability of the bridge was evaluated using three tensegrity modules (square, pentagon, and hexagon) via parametric analysis.
- The pentagon module exhibited the highest structural efficiency index among the three modules analyzed.
- Constructing and testing the prototype are highlighted as future objectives in the study.
Optimal tensegrity structures in bending: The discrete Michell truss[14]
In 2010, Robert E. Skelton, et. al established the minimal mass bending structure for a fixed complexity, mirroring Michell's result in an infinite complexity scenario.
- Study offered a complete solution for designing a cantilevered structure on circular foundation, supporting bending load with minimal material.
- This derivation expanded Michell's results to a wider range of load directions, increasing its practical utility beyond vertically applied loads.
Topology optimization of tensegrity structures under compliance constraint: a mixed integer linear programming approach[15]
In 2011, Yoshihiro Kanno investigated different arrangements of tensegrity structures through topology optimization, considering compliance and stress constraints.
- The topology of tensegrity structures, defined by member connectivity and labeling, posed challenges due to the discontinuity condition of struts.
- This work introduced mixed integer linear programming (MILP) technique,eliminating the need for pre-existing connectivity information.
- Proposed optimal tensegrity configurations based on experimental results.
Tensile Tensegrity Structures[16]
In 2012, Robert E Skelton and Kenji Nagase conducted research on determining the optimal angles between strings and the complexity of tensile structures
- The objective was to minimize system mass while satisfying stiffness constraints.
- Study provided formulas for calculating minimum mass and optimal complexity of tensegrity structures with one bar and four strings per unit.
- This formulas could be utilized for finding the optimal pitch of stranded cables in future research.
Kinetic Geiger Dome with Photovoltaic Panels Structural Membranes 2013[17]
In 2013, A.D.C. Pronk and his team detailed a kinetic geometry of a Geiger dome to integrate a sun tracker.
- Applied alterations by adapting the conventional tensegrity structure in three distinct manners.
- Built prototypes with limited spans, culminating in a final kinetic Geiger dome with a span of about 4 meters.
- Future plans include widening the span, integrating electric motors, and ensuring optimal functionality by pre-tensioning the geometry.
Optimal design and dynamics of truss bridges[18]
In 2015, G. Carpentieri et al. presented the minimum mass design of tensegrity structures under distributed bending loads.
- Explored the impact of varying prestress states on the bridge's vibration modes.
- Exemplified optimizing bridge dynamic performance by adjusting prestress of deck member.
Minimum Mass and Optimal Complexity of Planar Tensegrity Bridges[19]
In 2015, G. Carpentieri, et. al discussed minimal mass bridge designs for structures allowing substructure and superstructure with varying complexities and configurations.
- The substructure bridge proved most efficient and cost-effective due to its simplified structure and minimal mass compared to other configurations.
- This design ensured the lightest bridge construction possible by selecting appropriate materials.
A minimal mass deployable structure for solar energy harvesting on water canals[20]
In 2016, Gerardo Carpentieri, et. al proposed design for a lightweight support structure for solar panels placed over water canals, based on tensegrity principles.
- Provided a mathematical expression for determining the optimal complexity of the tensegrity system, considering both material properties and the weight of solar PV modules used in the bridge.
- While economic aspects weren't fully explored, the paper emphasized the technical feasibility and resource efficiency of the proposed designs.
Low-cost racking for solar photovoltaic systems with renewable tensegrity structures[10]
In 2021, Shamsul Arefeen and Tim Dallas explored the feasibility of tensegrity as a cost-effective racking system for solar panels.
- Integrated the electrical aspects of solar PV system design with tensegrity structural elements using a novel algorithm.
- The validation was conducted through SAM modeling and MATLAB implementation of a minimal mass planar bridge tensegrity model.
- Evaluated costs,showing tensegrity structure superiority in baseline BOS expenses.
Potential of tensegrity racking structures for enhanced bifacial PV array performance[21]
In 2024, Shamsul Arefeen and Tim Dallas investigated tensegrity racking as an alternative to traditional PV racking, focusing on their potential for bifacial performance.
- Radiance ray-tracing was used to compare tensegrity and conventional racking performance.
- Detailed racking geometry modeling showcased tensegrity structures' potential to enhance bifacial PV arrays.
- ↑ .A. J. Buitenhuis and J. M. Pearce, “Open-source development of solar photovoltaic technology,” Energy Sustain. Dev., vol. 16, no. 3, pp. 379–388, Sep. 2012, doi: 10.1016/j.esd.2012.06.006.
- ↑ B. Wittbrodt and J. M. Pearce, “3-D printing solar photovoltaic racking in developing world,” Energy Sustain. Dev., vol. 36, pp. 1–5, Feb. 2017, doi: 10.1016/j.esd.2016.08.001.
- ↑ B. T. Wittbrodt and J. M. Pearce, “Total U.S. cost evaluation of low-weight tension-based photovoltaic flat-roof mounted racking,” Sol. Energy, vol. 117, pp. 89–98, Jul. 2015, doi: 10.1016/j.solener.2015.04.026.
- ↑ J. M. Pearce, J. Meldrum, and N. Osborne, “Design of Post-Consumer Modification of Standard Solar Modules to Form Large-Area Building-Integrated Photovoltaic Roof Slates,” Designs, vol. 1, no. 2, Art. no. 2, Dec. 2017, doi: 10.3390/designs1020009.
- ↑ B. Wittbrodt, J. Laureto, B. Tymrak, and J. M. Pearce, “Distributed manufacturing with 3-D printing: a case study of recreational vehicle solar photovoltaic mounting systems,” J. Frugal Innov., vol. 1, no. 1, p. 1, Nov. 2015, doi: 10.1186/s40669-014-0001-z.
- ↑ P. Mayville, N. V. Patil, and J. M. Pearce, “Distributed manufacturing of after market flexible floating photovoltaic modules,” Sustain. Energy Technol. Assess., vol. 42, p. 100830, Dec. 2020, doi: 10.1016/j.seta.2020.100830.
- ↑ M. Hollman and J. Pearce, “Geographic potential of shotcrete photovoltaic racking: Direct and low-concentration cases,” Sol. Energy, vol. 216, pp. 386–395, Mar. 2021, doi: 10.1016/j.solener.2021.01.051.
- ↑ Y. Bansod, D. Nandanwar, and J. Bursa, “Overview of tensegrity – I: basic structures,” Eng. Mech., vol. 21, pp. 355–367, Dec. 2014.
- ↑ J. M. Mirats Tur and S. H. Juan, “Tensegrity frameworks: Dynamic analysis review and open problems,” Mech. Mach. Theory, vol. 44, no. 1, pp. 1–18, Jan. 2009, doi: 10.1016/j.mechmachtheory.2008.06.008.
- ↑ 10.0 10.1 S. Arefeen and T. Dallas, “Low-cost racking for solar photovoltaic systems with renewable tensegrity structures,” Sol. Energy, vol. 224, pp. 798–807, Aug. 2021, doi: 10.1016/j.solener.2021.06.020.
- ↑ G. Carpentieri, F. Fraternali, and R. E. Skelton, “A Tensegrity Paradigm for Minimal Mass Design of Roofs and Bridges,” in Innovative Numerical Approaches for Multi-Field and Multi-Scale Problems: In Honor of Michael Ortiz’s 60th Birthday, K. Weinberg and A. Pandolfi, Eds., in Lecture Notes in Applied and Computational Mechanics. , Cham: Springer International Publishing, 2016, pp. 91–114. doi: 10.1007/978-3-319-39022-2_5.
- ↑ A. G. Tibert and S. Pellegrino, “Deployable Tensegrity Reflectors for Small Satellites,” J. Spacecr. Rockets, vol. 39, no. 5, pp. 701–709, 2002, doi: 10.2514/2.3867.
- ↑ L. Rhode-Barbarigos, N. B. Hadj Ali, R. Motro, and I. F. C. Smith, “Designing tensegrity modules for pedestrian bridges,” Eng. Struct., vol. 32, no. 4, pp. 1158–1167, Apr. 2010, doi: 10.1016/j.engstruct.2009.12.042.
- ↑ R. E. Skelton and M. C. de Oliveira, “Optimal tensegrity structures in bending: The discrete Michell truss,” J. Frankl. Inst., vol. 347, no. 1, pp. 257–283, Feb. 2010, doi: 10.1016/j.jfranklin.2009.10.009.
- ↑ Y. Kanno, “Topology optimization of tensegrity structures under compliance constraint: a mixed integer linear programming approach,” Optim. Eng., vol. 14, no. 1, pp. 61–96, Mar. 2013, doi: 10.1007/s11081-011-9172-0.
- ↑ R. E. Skelton and K. Nagase, “Tensile Tensegrity Structures,” Int. J. Space Struct., vol. 27, no. 2–3, pp. 131–137, Jun. 2012, doi: 10.1260/0266-3511.27.2-3.131.
- ↑ A. D. C. Pronk, M. M. T. Dominicus, and J. da Conceicao van Nieuwenhuizen, “Kinetic geiger dome with photovoltaic panelsstructural membranes 2013: 6th International Conference on Textile Composites and Inflatable Structures, Structural Membranes 2013,” VI Int. Conf. Text. Compos. Inflatable Struct. Struct. Membr. 2013 Oct. 9-11 2013 Munich Ger., pp. 461–472, Oct. 2013.
- ↑ G. Carpentieri, M. Modano, F. Fabbrocino, and F. Fraternali, Optimal design and dynamics of truss bridges. 2015. doi: 10.7712/120115.3497.632.
- ↑ “Minimum Mass and Optimal Complexity of Planar Tensegrity Bridges - Gerardo Carpentieri, Robert E. Skelton, Fernando Fraternali, 2015.” Accessed: Mar. 11, 2024. [Online]. Available: https://journals.sagepub.com/doi/abs/10.1260/0266-3511.30.3-4.221
- ↑ G. Carpentieri, R. E. Skelton, and F. Fraternali, “A minimal mass deployable structure for solar energy harvesting on water canals,” Struct. Multidiscip. Optim., vol. 55, no. 2, pp. 449–458, Feb. 2017, doi: 10.1007/s00158-016-1503-5.
- ↑ S. Arefeen and T. Dallas, “Potential of tensegrity racking structures for enhanced bifacial PV array performance,” Sol. Energy, vol. 269, p. 112344, Feb. 2024, doi: 10.1016/j.solener.2024.112344.