Erasmus placement student Yoko van der Sterre has undertaken a study on solar-powered liquid-desiccant cooling systems for greenhouse cultivation of tomatoes in Jeddah, Saudi Arabia. With growing populations and scarce water resources, Middle Eastern countries like Saudi Arabia are looking for new ways to produce their own food. One solution is to grow crops in water-efficient greenhouses but, under the extremely hot climate, greenhouses will require refrigeration. Research at the Sustainable Environment Research Group previously showed the feasibility of using solar-cooling systems to lengthen the growing season for a variety of crops, but the systems require large solar collectors to regenerate the desiccant solution. Regeneration refers to the process of driving moisture out of the desiccant so that it can be repeatedly re-used. The solar collectors may occupy more area than the greenhouse itself which would be expensive.
Visiting Aston from HAS University of Applied Sciences in the Netherlands, Yoko proposed to carry out the regeneration using vacuum evaporators with thermal compression. The compressor can be powered by electricity obtained from PV arrays. He calculated that a PV array of area 474 m2 would be needed to cool a greenhouse of area 1000 m2. He also compared the carbon footprint of solar-cooled local cultivation against import by ship and lorry from the Netherlands, where greenhouses are heated using combined heat and power systems fuelled by natural gas. Using Life Cycle Assessment software Simapro 8, he found that local cultivation with PV will result in a carbon footprint of 0.0886 kgCO2 per kg of tomato which is 10 times lower than the footprint of imported tomatoes at 0.88 kgCO2/kg. But if the solar-powered cooling system is powered by conventional grid electricity the carbon footprint is much higher at 1.76 kgCO2/kg. The study also considered the option of powering the compressor using electricity from a solar thermal power station using parabolic trough collectors. This options also has a favourable carbon footprint. Another benefit of using solar PV or solar thermal power is that, during some winter months, cooling may not be needed and the electricity could be sold or used for other purposes. (March 2014)
Philip Davies of the Sustainable Environment Research Group is representing Aston University on the newly formed Action Group of the European Innnovation Partnership on Water, alongside partners including Agricultural University of Athens, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (Almería, Spain), European Desalination Society, Fraunhofer Institute (Munich) and University of Palermo. The Action Group will promote the application of renewable energy to desalination at the European level. In Europe and many world regions, the demand for freshwater is outstripping supply. Increasingly people are turning to the sea as a source of water. The process of desalination involves removing the salt from seawater, to make it suitable for drinking, sanitation or irrigation. But desalination requires a large amount of energy, so it makes sense to use renewable energy instead of fossil fuels. Solar energy, for example, abounds in hot countries where water is most needed. Though the use of renewable energy for desalination is proven, there are many barriers to its adoption, and many improvements to the technology are possbile. As well as supporting R&D in this area, the action group will raise awareness of the of the available products and technologies and help to demonstrate their market potential. It will also work to bring about more effective policies for deployment of technologies that make sense for both the water and energy sectors. (Sept 2013).
Brian Price of the Sustainable Environment Research Group has obtained funding from the EC Marie Curie Programme to investigate overcoming the barriers to the adoption of electric vehicle through research on real drivers in a living lab in Denmark. The BUMILLA project will build on the work of the CABLED project which studied the behaviour of drivers of electric vehicles in the West Midlands. The CABLED project revealed that electric vehicles travel far enough and fast enough for 98% of journeys – but remain too expensive for most drivers. In collaboration with University of Gothenburg and Insero e-mobility, the Aston team will now study every aspect of electric vehicle usage for users living in a smart housing development having solar panels and intelligent energy management.
Not only can electric vehicles provide low- carbon transport, as vehicles are parked for 94% of the day, their large batteries can store electricity from the grid and sell it back when demand is high. This is vital in a country like Denmark which relies heavily on wind turbines, which are subject to intermittent supply and increasingly relevant to the UK energy sector. Speaking at a recent research seminar at Aston University, Price commented: ‘Vehicle users perceptions of their daily journey distances are often greater than reality. Thus their anxiety about the range of an electric vehicle is usually unfounded. Once this psychological problem is removed, the cost of electric vehicles is still a big issue. There are still only about 3,000 vehicles in the road in the UK which is way below the predictions from government and vehicle developers. To make electric vehicles more affordable, different business models are possible. For example, the driver can lease a battery on a ‘pay-as-you-go’ basis. BUMILLA will research business options using a real-life scenario based on the Living Lab.’ (February 2013)
Philip Davies of the Sustainable Environment Research Group has participated in a conference organised by the Sharing Knowledge Foundation, aimed at improving understanding among researchers and policymakers from countries North and South of the Mediterranean. Delegates leant about the very strong prospects for growth among African economies. This growth is going to require massive investments in basic infrastructure such as energy, water, transport and telecommunications. But many African countries still lack capacity in technology, financial institutions, and the underpinning educational sector. Growth in African economies may benefit the more stagnant economies of Europe by providing new markets and applications for technological developments.
Despite the vast land resources of the continent, Africa is still a net importer of food. Exports are hindered by the absence of roads and by complicated customs procedures. On the other hand, many promising developments are benefitting the rural population. One example cited at the conference was ‘i-Cow’, a mobile phone service helping Kenyan dairy farmers plan their daily activities and get veterinary advice. And in countries like Morocco there has been extensive electrification in the countryside with the use of photovoltaic panels.
Speaking in the session about alternative sources of water, Dr Davies gave his presentation on the long-term future of desalination powered by solar energy. The predicted shortfall in sustainable water resources over the coming decades is very serious. Across the Middle Eastern and North African region, demand is forecast to increase by 100 cubic kilometres per year by 2030 – equal to the flow of the river Nile. Most of this will be required for irrigation. Desalination is already providing an important source of water in Mediterranean countries such as Spain, Algeria and Israel. But it is expensive and one of the main reasons for this is the high usage of energy. In his presentation, Dr Davies showed that solar energy could help provide a sustainable solution. He highlighted some of the current research activities aimed at improving the processes of solar energy conversion and desalination. But there are also many low-cost ways of capturing and conserving freshwater resources, he pointed out, and he concluded that it is important to take an integrated approach to the management of energy and water resources to provide food for growing populations. (May 2012).
External link to Sharing Knowledge Foundation
PhD students Opubo Igobo and Clara Qiu have demonstrated ‘Desalink’: a new concept for high-efficiency desalination of groundwater. DesaLink will provide freshwater from brackish wells, while operating entirely from solar energy and producing a minimal waste stream of concentrated brine. At the recent launch event, visitors saw the machine operate continuously and drank the water it produced.
The prototype unit has been designed entirely at Aston University and built by a local company. It will find use in arid, salt-affected lands such as India, Egypt, Saudia Arabia and Australia. Shortage of freshwater tends to coincide with abundance of sunlight – so it makes sense to use solar energy to drive the desalination process. DesaLink is designed to work from low temperature heat, readily provided by solar, industrial or geothermal sources. The Aston team is keen to identify industrial partners to help commercialise this exciting development. (May 2012)
Solar photovoltaic cells are one of the fastest growing sources of energy. But today 95% of solar cells are made out of just one material, crystalline silicon, which is expensive to produce. Another downside is that it takes years for the cells to generate the amount of energy that went into making them.
Dr Paul Topham, Dr Andy Sutherland and their team of applied polymer chemists at Aston are working on new polymer-based materials to create the next generation of inexpensive thin-film organic solar cells. New polymer systems are incorporated into formulations that can be painted on to a variety of surfaces to produce flexible, lightweight films. The Aston team has recently joined forces with researchers across Europe to increase power efficiencies and lifetimes of the new photovoltaic devices using polymer nanotechnology.
‘Silicon solar cells have been under development since the 1950s and the technology has now reached something of a plateau,’ says Dr Topham, ‘Organic solar cells, on the other hand, are still very much in their infancy and with polymers each constituent of the cell can be tailored at the molecular level: the possibilities are virtually unlimited.’ (February 2012).
External link to European Consortium ESTABLIS
PhD students Jonathan Nixon and Opubo Igobo, of the Sustainable Environment Research Group, have designed and installed a new design of solar thermal collector on the roof of Aston University. The collector is electronically controlled to follow the movement of the sun. It will be used in India to provide a much needed energy source read more. (November 2011).
Members of the Sustainable Environment Research Group have contributed 6 articles to a Special Journal Issue reporting on more than 3 years of collaborative research between UK and Indian universities. Entitled Water Management & Biomass Production for Rural Energy Systems, the Special Issue covers topics including Rain Fed and Wastewater Irrigation, Treatment and Use of Brackish Water, and Biomass Energy Conversion. Further contributors include IIT Delhi, GP Pant University, Haryana Agricultural University, Rajasthan Agricultural University and the universities of Bristol, Coventry Leeds, and Warwick. Published in the Journal of Scientific and Industrial Research, the Special Issue is freely available to download at link. (August 2011).
Employable Graduates; Exploitable Research
© Copyright Aston University,
Birmingham, B4 7ET