Concentrated solar technologies have been successfully used to collect solar irradiance and transform it into useful heat for electricity generation. A problem in these systems is often that a mismatch between input and output is present due to variable solar irradiance and energy demand. To compensate for this mismatch storage is utilized to store heat during times when excess heat is present, which is subsequently released when the energy demand exceeds the
solar irradiance input. Phase change materials are a novel concept used to store heat by utilizing the energy required for a phase change and can be added to a heat transfer fluid tocreate a slurry with enhanced heat storage capabilities.\

A study has been conducted to identify characteristics of materials that are suitable for heat storage in a phase change material slurry and selected materials accordingly. This has been done for the specific operating temperature range between 200 ∘C to 300 ∘C. Using these materials a numerical model of a phase change material slurry has been developed to determine which parameters influence the performance of such a system and to establish a system that shows optimal thermal performance. To check if such a system is a good option for heat storage a comparison is made with a heat storage system where the phase change material is stored in a shell and tube packed bed.

A numerical model has been developed using the apparent heat capacity method to model the phase change. An analysis is performed to find the optimal sizing of the phase change slurry system. With use of a test case, a day with variable solar irradiance input and a fixed energy demand, the transient behaviour of the systems has been tested. A second comparison has been made for scaled up systems to limit the costs of the systems.

LiNO3 has been selected for the phase change material, encapsulated with engraved natural graphite, suspended in MarloTherm A. For the test case 91 643 units, a combination of a collector and heat exchanger to the organic Rankine cycle, are required when these are
designed for optimal thermal performance. The total mass of phase change material required equals 6575 kg, including storage. When applying the same sizing to the shell and tube packed
bed model it has been found that it can not meet the energy demand at all times throughout the day. Scaling up this system to more practical dimensions results in less units, 145, but the phase change material mass that is required increases to 99 061 kg.

With the parameters from the test case the transient behaviour of both systems has been analyzed. It was found that a smaller mass of phase change material is required for the phase change slurry system due to the possibility to cycle the phase change material faster between solid and liquid phase. Next to that the heat transfer fluid in the shell and tube packed bed system only contains sensible heat. Therefore less energy can be transferred when the heat
transfer fluid is at the same temperature as the phase change slurry model.

The urge for adventure combined with the global need for increasingly sustainable methods of air transportation resulted in a pioneering idea. What better way to show the possibilities of solar power by altering the accessible and entertaining nature of a paraglider? Personal experience and vision inspired the client to be the first to fly such an aircraft over the Atlantic Ocean to spread awareness for a more sustainable future. The mission was born: “Fly manned, continuously across the Atlantic using a solar powered paraglider.” Crossing the Atlantic requires the typical range of a paraglider to drastically increase. This combined with the current technology in terms of energy storage and solar power generation makes designing a struggle. Duration is a problem due to the slow, inefficient cruise phase. The purpose of this report is to investigate the feasibility of flying a solar powered paraglider over the Atlantic. The flight route and time of execution were based on the least amount of energy required to make the crossing. This means flying the shortest distance, with the most amount of sun hours per day, the highest solar intensity and the most advantageous tail winds. Impossible to maximise every parameter an optimal mission was determined to fly a rough 3040 km from St. John’s, Newfoundland Quebec to Portmagee, Ireland during the late June summer days. The design mainly evolved around flying with the least amount of energy required whilst still allowing a duration short enough for the pilot to cross without falling asleep. Flying efficiently typically means flying slow, but the aforementioned duration set a lower bound to this. The maximum mission duration was extended as much as possible by techniques such as blue light, stimulating substances, pilot health and pilot entertainment. By designing every part of the paraglider to be as lightweight as possible results in a cycle of less energy required, which in turn allows smaller subsystems, which in turn has lower weight. The subsystems were designed in a concurrent way. Progress in one part means changed inputs for another part. Integrated MATLABr tools based on analytic models were created to converge to an optimal design point for the subsystems in relation to each other. The subsystems and final product were analysed for sensitivity of their input values which helped identify the best solution for improvements. The final product was also analysed for its performance in order to check requirement compliance and the actual mission feasibility. The missions two most important limiting factors are the mission duration and the power required. In order to minimise mission duration the flight speed should increase whilst the opposite is true for the power required. This study revealed that power required was the limiting factor so a lower flight speed was chosen. For the chosen cruise speed of 10 m· s−1 the resulting mission duration was 38 hours and the power required ended up to be 3.79 kW. The total mass of the vehicle is 277 kg of which 23% is battery mass and 16% solar cell mass. The high energy density lithium-sulphur batteries are still in development, but are expected to be available within 5 years. Currently available batteries would make the design too heavy. This study was initiated as a concept study. With a custom designed wing and fuselage the mission is shown to be technically feasible in 5 years time. The limited scope and duration of this project allows for more improvements for which this report can be used as a guideline.