• Energy Research
• Closed Access close
• AU close
• NL close
• UA close
• Renewable Energy close

In the present study, Tween 80, a non-ionic surfactant, has been used for enhanced hydrogen production by crude glycerol bioconversion using co-culture of Enterobacter aerogenes and Clostridium butyricum. The purpose of introducing the surfactant was to decrease the crude glycerol viscosity, so that apparent solubility and bioavailability of glycerol could be improved at the expenses of pretreatment steps. Experiments were planned using central composite design (CCD); crude glycerol and Tween 80 concentrations were optimized whereas, hydrogen production, glycerol utilization and viscosity of the media were considered as responses. The response surface for quadratic model showed, Tween 80 concentration had significant effect (p < 0.05) on all the three responses. Using the optimized conditions at 17.5 g/L crude glycerol and 15 mg/L Tween 80, hydrogen production reached a maximum of 32.1 ± 0.03 mmol/L of medium. The increase in hydrogen production was around 1.25-fold in presence of Tween 80 in comparison to its absence with 25.56 ± 0.91 mmol/L production. Selected optimum conditions were also validated against absence of crude glycerol (4.69 ± 0.76), with pretreated crude glycerol (20.06 ± 0.51) and across mono-culture system (15.43 ± 0.79 to 22.14 ± 0.94). Introduction of Tween 80 to the fermentation medium improved the glycerol utilization rate, resulting in increased hydrogen production and eliminated pretreatment steps.

Although considered a current highlight, the concept of intelligent buildings (IB) has not been adopted as quickly and widely as expected. One of the reasons for this is the lack of information and knowledge support to all professionals involved at the design stage of a project. This paper provides a brief overview on the new advances of IB technologies and discusses ways of supplementing the decision making process by adopting two methods for economical and technical aspects of IB applications. It goes on to introduce an on-going research which aims to utilise knowledge based systems to provide comprehensive evaluations to alternatives and decision support to retrofit building projects, when they are being conceptualised.

Access to a reliable source of electricity is a basic need for any community as it can improve the living standards characterized via the improvement of healthcare, education, and the local economy at large. There are two key factors to consider when assessing the appropriateness of a micro-grid system, the cost-effectiveness of the system and the quality of service. The tradeoff between cost and reliability of the system is a major compromise in designing hybrid systems. In this way, optimization of a Hybrid Micro-Grid System (HMGS) is investigated. A hybrid wind/PV system with battery storage and diesel generator is used for this purpose. The power management algorithm is applied to the load, and the Multi-Objective Particle Swarm Optimization (MOPSO) method is used to find the best configuration of the system and for sizing the components. A set of recent hourly wind speed data from three meteorological stations in Iran, namely: Nahavand, Rafsanjan, and Khash, are selected and tested for the optimization of HMGS. Despite design complexity of the aforementioned systems, the results show that the MOPSO optimization model produces appropriate sizing of the components for each location. It is also suggested that the use of HMGS can be considered as a good alternative to promote electrification projects and enhance energy access within remote Iranian areas or other developing countries enjoying the same or similar climatic conditions.

Abstract A simple way to improve its power coefficient (cp) of a Savonius turbine is by its installation above a cuboidal building as the building will redirect the wind and increase its speed significantly. To determine the gain, a turbine was constructed and installed above a bluff body and tow tested. Detailed measurements of vehicle speed and turbine power were made. Tow test speeds were 8, 10 and 12 m/s, while TSR range was 0.6–1.1. Most importantly, wind speed at the position beside and slightly above the turbine was measured during test runs. The cp calculated using this measured wind speed was used to validate CFD simulation results. Simulation results were also used to obtain the relationships between the wind speed of the free stream and at the anemometer position. Typically, wind speed at the anemometer position is about 9% higher than those of the free stream. These relationships were used to derive the free stream wind speed of each experimental run. The cp calculated using these derived free stream wind speeds showed an increase of 25% at 12 m/s wind speed, compared to the cp reported by previous researchers for a similar turbine operating in unmodified air flow.

While the member states of the Gulf Cooperation Council have economically and politically been dominated by the exploitation of fossil fuels, recent years have seen an increasing adoption of renewable energy technologies, the reasons of which are not yet sufficiently understood. This paper argues that the recent adoption of renewable energy technologies in the Gulf and its striking variation can be explained by theories of policy transfer. In addition, we find some support for the alternative hypothesis of endogenous policy development regarding political leadership. Yet there is no support for the alternative hypothesis of a strong direct influence of the international climate regime. Furthermore, the policy transfer hypothesis and political leadership stand as coexisting influences on renewable energy adoption, rather than competing ones. Based on an extensive study of primary and secondary sources, local reports and country analyses of international organizations, and personal interviews with key experts, this paper lays out in detail how transfers of renewable energy policies take place in the Gulf; their drivers; and their impacts. We also discuss the factors that lead countries to lag behind, which can be helpful for prospective research on a more extensive utilization of renewable energy in the region and beyond.

Abstract Generation is most valuable when demand is highest. As electricity can't yet be cheaply stored, generation and transmission infrastructure must be built to meet the highest expected demand, plus a margin of error. Reliably producing power at times of critical demand not only offsets the need to use expensive liquid fuels such as diesel or condensate, but also removes the need to build backup power stations and transmission infrastructure that would only be used for a small fraction of the year. Under the most extreme demand conditions, solar has reduced the peak demand seen by retailers and wholesale energy markets. This study compares the capital cost of critical peak availability from gas turbines to the capital cost of critical peak availability from distributed solar in the Australian National Electricity Market (NEM). When compared on this basis, 10–22% of the cost of installing the solar system can be attributed to the capital value of critical peak generation. North–west and west facing PV is worth a further 3–6% of system installation costs when compared to generally north facing PV. Finally, southern states, with longer summer days and more sunshine in the afternoon are found to benefit more from peak supply of solar PV.

This paper describes the influences which govern solar box cookers: HS 7534, HS 7033 and the newest design HS 5521. The best of solar cooker, type HS 7033 gave oven temperature of 202°C between 12:00 and 12:45 p.m. on October 7, 1997. Thirty-four units of this type have been field tested since September 1997. It was found that these solar cookers have a good heat storage capability, therefore they can be used for consecutive cooking. The optimization of the size, the aperture area, the insulator thickness, the oven volume and the reflector area leads to a new design, type HS 5521. Its volume is only 35% of the volume of HS 7033 and cheaper. The performance comparison of the last two solar cookers are described based on the data collected during testing with and without load. The HS 5521 has the same heat collection rate and is able to cook as fast as HS 7033. The performance of three types of solar cookers available in Indonesia was analyzed and compared. Field tests demonstrated that type HS 7033 feature good heat storage capability and can be used for consecutive cooking. Type HS 5521 was designed on the basis of size, aperture area, insulator thickness, oven volume, and reflector area optimization of HS 7033 specifications. The new design has a volume only 35% that of HS 7033 and is less expensive to construct and operate. HS 5521 also has the same heat collection rate and can cook as fast as HS 7033. (from World Renewable Energy Conf Proceedings, Perth, Australia, Feb 99).

The conversion of biogas to biomethane represents an attractive solution to replace fossil gas with a renewable gas. However, removal of such a large percentage of CO2 from a fuel gas comes at a significant energy cost using the conventional CO2 capture technologies and hence has led to an opportunity to develop an alternative technique for large-scale carbon capture. Results of the current study suggest that employing an anion exchange membrane (AEM)-based alkaline water electrolyser for CO2 removal from gas mixtures offers an energy-efficient strategy for the capture and removal of CO2 from biogas. After capturing CO2 in an aqueous absorption column, the resulting bicarbonate solution was fed through the cathode of an AEM-based electrolyser. Although the CO2 absorption rate increased from about 300 to 900 mol m−3 h−1 when the pH was elevated from 9 to 13, the system's energy requirement was lowest at pH = 9. The economic assessment shows that the electrochemical work requirement for CO2 removal from biogas using the AEM-based alkaline electrolyser ranges between 0.25 and 0.92 kWh/kg CO2 at optimum conditions (pH = 9). This could potentially reduce the energy input for CO2 removal by about 50% compared to commercially available biogas upgrading technologies.

Abstract This paper argues that “sustainablity” will remain a peripheral architectural issue until it forms part of a contemporary architectural paradigm. The paper explores a number of approaches for relating energy and environment to the central architectural issues of form and space making.