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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.

Abstract The increased environmental awareness coupled with the recent changes in the oil prices triggered the necessity of focusing on effective management of energy systems. Global climate change has caused many people to consider ways of reducing greenhouse gases Renewable energy has become an essential feature in curtailing emission of Green House Gases, while meeting the demand for energy. This paper presents an innovation system framework for development and diffusion of renewable energy technologies. The framework is used to identify opportunities for small and medium enterprises in the renewable energy sector. A case study on a successful development, installation and implementation of solar thermal systems households in Calgary, Alberta, by an entrepreneurial firm, is also presented.

Abstract For the first time the electrical conductivity of bamboo biographite-based material reported a ground-breaking milestone of 4.4 × 104 (S/m). This reported conductivity by far exceeded all previous reported conductivity measurements obtained from renewable carbon. Controlled high-temperature thermal carbonization of biomass, notably Asian bamboo, at extended residence times elicited surprising growth of nano-layered biographitic structures with a layer-to-layer distance of less than 0.3440 nm. Moreover, thermodynamically dispersed bamboo and pine biographitic nano-layered carbon-based lightweight composites in a polyamide matrix were found to be intrinsically conductive both thermally and electrically. Electromagnetic interference (EMI) shielding device made from bamboo renewable carbon/cellulose nanofiber (CNF) composites possesses EMI shielding effectiveness (SE) of ∼23 dB. These results constitute a new advancement in the materials science of nano-layered graphites from renewables and their applications as EMI filtering devices and as electrode materials in air cathodes, electronics, supercapacitors in energy storage devices, and thermal management of batteries and sensors.

Abstract Tilt angle of photovoltaic (PV) panel strongly contributes to the amount of solar radiation harvested by the PV panel. In this paper, we model the optimal PV tilt angle for Lahore and some of the other major cities in Pakistan using the available solar radiation data from NREL and ESMAP. The model is used to propose an optimal schedule for PV tilt in Lahore involving four adjustments in a year that can provide ∼6.6% increase in the yearly energy generation relative to a fixed tilt. The model is validated with PV tilt experiments. Moreover, a simple model is developed to estimate the upper/lower bounds of soiling losses in Lahore using the reported distributions for aerosol particulates. We show that the power loss due to soiling could be up to 10% for a lightly soiled panel and could go up to 40% for a heavily soiled panel. We further explore the tilt angle effect on the soiling losses in Lahore by doing soiling experiments. For a period of 100 days, dust deposition on a horizontal panel results in 26.2% energy loss as compared to a clean panel. For the same period, the corresponding loss for a vertical tilt was 13.5%. The variability of soiling effects with respect to tilt is used to predict an optimal tilt angle when the soiling losses are significant. These findings provide important insights into the protocols of tilt adjustments in presence of environmental dust for PV systems in Pakistan and further highlight the significance of soiling losses for the typical aerosol conditions in Lahore.

Off-grid electricity generation using renewable energy technologies has become a more reliable source to fulfill the needs of rural areas at limited level without considering conventional resources. The main purpose of this study was to propose an economical and optimized design for electricity generation using hybrid energy source PV/Biomass for an agricultural farm and a residential community centered in a small village of district Layyah in the Punjab province of Pakistan. The electric load data was collected for the irrigation and residential needs. Hybrid Optimization Model for Electric Renewable (HOMER) was used to design and perform techno-economic analysis to meet the load requirements using PV/biomass hybrid configuration. The solar irradiance data and the available biomass potential on the farm was used in the HOMER software to perform the analysis. Total net present cost (NPC) and cost of electricity (COE) were obtained as a solution by the HOMER analysis and then these results were refined further by performing sensitivity analysis. Sensitivity parameter such as biomass potential, biomass price, solar irradiance and variations in loads were used in the sensitivity analysis. This analysis compares the performance of the system and shows that system is techno-economically viable based on the net present cost and cost of energy.

Abstract In Ontario (Canada), the integration of renewable power is a priority policy goal. Since 2004, the circumstances under which the integration of renewable power is evaluated have changed due to successive changes in price as well as concerns that its over-production may add to grid congestion. This research investigates the value of increasing complementarity (both proximate and geographically dispersed) of wind and solar resources as a means by which electricity planners and researchers might advance electricity sustainability in Ontario. More specifically, this paper asks the following questions: 1) Does the combination of solar and wind resources in selected locations in Ontario serve to ‘smooth out’ power production, i.e., decrease instances of both high and low values, as compared to either resource producing individually? 2) Can this ‘smoothness’ be further improved by dispersing these resources geographically amongst locations? and 3) Does increasing the number of locations with solar and wind resources further ‘smooth out’ power production? Three years (2003–2005) of synchronous, hourly measurements of solar irradiance and wind speeds from Environment Canada’s Canadian Weather Energy and Engineering Data Sets (CWEEDS) are used to derive dimensionless indices for four locations in Ontario (Toronto, Wiarton, Sault Ste. Marie and Ottawa). These indices are used to develop three transparent and accessible methods of analysis: (1) graphical representation; (2) percentile ranking; and (3) using a theoretical maximum as a proxy for capacity. The article concludes that the combination of solar and wind within locations and amongst two locations improves ‘smoothness’ in power production, as compared to when each resource is produced on its own; moreover, it is further improved once more than two resources and two locations are combined. However, there is neither further benefit, nor drawback, associated with the geographic dispersion of complementarity between solar in one location and wind in another, when compared to both resources in one location.

Abstract In this paper, the charging/melting of phase change materials (PCM) in thermal energy storage is discussed. An oil-driven system is considered in which oil acts as a heat-transfer fluid while solar salt (KNO3 – NaNO3) is used as a PCM. The aim of this study is to analyze the influence of increasing the number of heat transfer fluid HTF tubes during the charge cycle as a geometrical factor. The effect of changing inlet temperature is also examined. Four cases of geometric configurations are analyzed in this research in order to understand the effect of increasing the number of HTF tubes on the total melting time of PCM. Moreover, three inlet temperature conditions are considered to study their influences on melting time. Results indicate that by increasing the number of HTF tubes, total melting time of PCM decreases as it liquefies in four tube cases in almost 165 min, as compared with a single tube which took 234 min to completely melt. Furthermore, inlet temperature plays an essential role in reduction of total melting time.