Development and field testing of stand-alone solar thermal energy conversion systems for remote community applications

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Roughly 1.1 billion people lack access to clean drinking water, and it is expected that up to 40% of the world's population will face water shortages by 2030. Due to a direct correlation between countries experiencing the highest levels of water scarcity and those that have the highest solar potential, a number of technologies have been developed over recent decades that utilize solar thermal energy as a primary energy source for water purification. Overall, Canada does not have a water shortage, but remote Indigenous communities often face profound challenges in accessing clean drinking water and many depend on bottled water on a daily basis due to frequent long-term drinking water advisories. These communities are highly reliant on expensive fossil fuel as their energy supply, which could be used to provide high quality water, while also being under pressure from the federal government to meet GHG targets. With this background as the motivation for the proposed research program, the long-term objective is to explore and advance the technologies associated with addressing the nexus of problems of water quality, energy use, and GHG emissions that will be useful to government, academia, and the private sector for guiding policy development, informing scientific inquiry, and providing potential pathways for commercialization, respectively. In the first instance, this research will be directed to the problems in Canada, but with an eye on global impact, especially in climates similar to Canada's. The next five years of this research program will focus on breaking new ground in the design and optimization of solar thermal assisted multi-effect distillation water purification systems (solar-MEDs). These systems operate at low temperature and make use of multiple tanks for evaporating non-potable feed water at sub-atmospheric pressures to produce fresh water. The shorter-term objectives being addressed relate to the translation of the solar MED's effectiveness in hot arid climates where sunlight is abundant, in order to improve their performance in other remote and less favorable climate regions of the world, and identifying evidence-based approaches for increasing system performance and reducing cost. The proposed system will comprise novel features such as an optimized distillation tank heat exchanger design, and absorption heat pump waterside economizer, and a cascading vapor circuit fitted with pressure reducing valves to maximize distillation efficiency. The system will additionally include a novel latent heat thermal storage tank, and photovoltaic-battery system to enable extended system operation in off-grid environments. The full proposed system design will be assessed via the development of a validated numerical model. The complimentary goal is to train a group of HQP in the understanding and modeling of practical, multi-device, hybrid energy systems, as these skills will be needed as part of Canada's transition to a sustainable society.