Structural and aesthetic design applications of flexible, thin-film solar cells to power off-grid tensile structures

Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, May, 2020Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official pdf version of thesis. "May 2020."Includes bibliographical references (pages [75]-[77]).Despite global trends in decreasing costs of silicon-based solar panels, the adoption of solar energy solutions as an alternative to fossil fuels has been impeded by high installation and manufacturing costs, as well as challenges in the customization of solar panels for different products and environments. Moreover, silicon-based photovoltaic cells, due to their rigid nature, change the aesthetic of the surfaces on which they are placed and often only provide the singular function of harvesting energy. The current solar energy products function independently from the architecture on which they are installed, making them difficult to blend in with the design and functional requirements of the products and buildings on which they are installed. Fundamentally, the installation costs associated with silicon crystalline PV cells account for a significant percentage of solar energy solutions. This thesis aims to push the boundaries of solar panels to provide the dual functionality of energy harvesting and architectural structure, while either maintaining or improving the aesthetics of the architecture on which they are placed. To achieve this, this research explores a new use case for flexible thin-cell solar panels that includes the use of organic photovoltaic (OPV) and perovskite solar cell technology. Through a product-design approach, this thesis explores use cases where the technology's uniquely-flexible, ultra-thin, lightweight, and low-cost key features are best applied as a solar energy source. Particularly, this research focuses on off-grid architecture with non-rigid roofing structures where fossil fuels are currently used as the primary energy source. Through design research and stakeholder interviews, a key insight that was uncovered was the opportunity to integrate flexible OPV solar cells in glamping and luxury safari camp as an alternative to the current option of diesel fuel. This achieves the goal of providing a clean energy source while maintaining the aesthetic of the luxury camp and the outdoor safari experience.by Juliet Wanjiru Wanyiri.S.M. in Engineering and ManagementS.M.S.M.inEngineeringandManagement Massachusetts Institute of Technology, System Design and Management ProgramS.M. Massachusetts Institute of Technology, Department of Mechanical Engineerin

Leveraging microgravity to investigate earth- And space-based centrifugal casting of wax

A multi-year research effort aimed at increasing understanding of the centrifugal casting process of wax fuels for hybrid chemical propulsion in multiple thermal and gravitational environments is described. As both radiative and convective heat transfer drive the casting process, the suborbital and orbital microgravity environments are critical to disentangling these contributions to heat transfer away from the fuel. The experimental effort comprises testing on multiple platforms, including the ambient atmosphere of the laboratory, as well as various mobile microgravity platforms. Testing onboard reduced-gravity aircraft facilitates increased understanding of how these types of fluids perform in the microgravity environment, while a suborbital spaceflight and orbital platform under standard atmosphere allow for longer-term observation of natural convection sans buoyancy. An orbital platform subjected to the space environment facilitates understanding of the contribution of radiation to the heat transfer away from the liquid fuel. Each progressive testing environment requires updates to the experimental setup in order to accommodate respective physical and electrical constraints which are described in detail herein. An image analysis routine was developed in order to automate post-processing and determine the solidification front speed for each test. A rotation rate actuation routine is in development which aims to improve the accuracy of the centrifuge control system by leveraging electromagnetic sensing and feeding back rotation rate measurements to the motor driver. Preliminary modeling work was conducted which aims to elucidate the fundamental physics of the centrifugal casting problem; specifically, the impact of rotation rate, material properties, and environmental conditions on the heat transfer and fluid mechanics which constitute the larger casting problem. Both paraffin wax - a solid fuel with two decades of heritage - and the more novel beeswax are considered in this study