In recent years, much research has focused on the possibility of using arrays of turbines to generate clean and predictable power from tidal currents. The first such array is now in development but a number of important questions remain unanswered. Among these, how should turbines be arranged within a tidal stream to maximise their collective performance? And what impacts will such devices have on the marine environment? In beginning to address these questions, this thesis takes two important steps toward establishing best practice in the design of tidal turbine arrays. In the first part of the thesis, the social and ecological impacts of marine energy development are reviewed. This review highlights the importance of communication and public engagement in securing support for a marine energy project and identifies the effects of increasing noise and collision risk on marine life as the most pressing ecological issues to be addressed. In the second part, theoretical models of tidal turbines are examined and a simple numerical model is used to extend existing theories on optimal turbine arrangement. The shallow water equations are used to simulate flow through an idealised channel and an actuator disc model is used to represent a single row of tidal turbines as a line sink of momentum. Optimal turbine arrangements are then sought for different and increasingly realistic flow conditions. Results provide new and important insights into the dynamics of flow through partial-width arrays and suggest that arranging turbines unevenly within the flow cross-section can increase considerably their collective power output.

Purpose: this degree project investigates the homeowner’s knowledge about their energy use and the impact of using visualisation tools such as thermal imaging to enhance public engagement in energy conservation in building. Additionally, the study try to increase the understanding of how people's behavior affects the energy use in buildings. The method: the presented study is based on 12 participants who own a single-family house in central Sweden. Participation in this study involved responding to two questionnaires and conducting a thermography inspection. A methodology developed to replace a standard thermography inspection with a DIY themography survey. The study identified and filled the gap in the literature, by allowing house owners to carry out the thermographing inspection of their own buildings, free of charge and by themselves. The participants took part of a developed educational material that helps in increasing energy awareness and includes explanations about how to interpret the thermal images and provides suggestions for possible conservation measures. Finally, a data analyse carried out based on questionnairs, thermal images and communications with the house owners. The results: cold bridges are the most common cause of heat loss in the inspected single-family houses. Householders with older buildings who have long term plan to live in their building are willing to implement measures, while participants with newer buildings do not consider it as necessary. The infrared camera has been an effective tool for visualization of heat loss and attract attention. Many participants are surprised over the results. Conclusion: the study confirms that the infrared camera is an effective tool for heat loss visualization and can be used for enhancing public engagement in energy conservation in building. Thanks to this visualization, Swedish homeowners have gained an increased interest in energy-efficient measures such as additional insulation, window replacement and sun protection. The study has increased the general awareness and knowledge regarding energy efficiency in buildings.