Currently biofuel production from microalgal biomass is less attractive due to cost consideration despite having enormous potential. Researchers are increasingly focusing on, among others, the best utilisation of microalgal bioproducts to make biofuel production commercially viable. As freshwater and marine algae live in various environmental conditions, they develop special defense mechanisms to survive by producing a wide range of chemical compounds in their body. These chemical compounds are the commercial sources of various high-value bioproducts that can be used for health and other benefits. Although most publications have focused on biofuel production from microalgae, scant information is available on microalgal bioproducts and their applications in the open literature. Therefore, the primary objective of this article is to review the existing and potential high value bioproducts (other than biofuels) from microalgae and their current industrial applications. The review summarises microalgal bioproducts and their current uses in nutraceuticals, cosmeceuticals, pharmaceuticals, aquatic and terrestrial animal husbandry, food industry etc. to make biofuel production more commercially viable.
The catalytic oxidation of NO using activated carbons provides a promising alternative for the control of emission of waste incineration plants air pollutant. In this study, an activated carbon named AC-1 was made from coconut shell and was activated using steam. It was found that the presence of oxygen promoted the NO removal significantly. The NO removal efficiency of AC-1 was approximately 87%. The investment cost for the case using AC-1 is 0.85 times that using selective catalytic reduction (SCR). In addition, the operation cost of the case using AC-1 was from 9.7% to 23.6% of that of SCR method. The potential of the AC-1 for the denitration of the waste incineration plants is promising.
International organisations, unions and countries are taking part in reduction of pollutants from different sources by setting emission limits and boundary values for pollutants such as carbon dioxide, carbon monoxide, sulfur oxides, nitrogen oxides and particulate matter. According to EU Eco-design Directive each solid fuel household boiler technology has to include electric precipitator. A fog unit is a novel flue gas treatment technology made for small capacity combustion units. First experiments have been carried out in the fog unit experimental stand and results are analysed in detail. The capacity of the fog unit reached during experiments was between 1.02kW and 3.11kW, showing increase in efficiency from 5 to 15%. Data of experiments were used in a simulation (calculation) model, made for determination of fog unit capacity. Results of the model and experiments were compared and showed strong compatibility.
This study proposes a novel multiple-objective forest biomass-to-biofuel facility location problem with social consideration and uncertainties, which determines locations of forest biomass-to-biofuel facilities so as to satisfy the energy demand, while the scale of facilities is limited. Aside from the two objectives (i.e., minimizing cost and pollution) that were often discussed in previous problems, the problem in this study additionally considers an objective from the social aspect, i.e., maximizing the job opportunity by opening facilities. Furthermore, many uncertain factors may affect the number of days of operating biomass energy facilities as well as biomass production; the demand of biomass energy is uncertain with the unstable price of fossil fuels; and the number of job offers is uncertain. Therefore, we adopt fuzzy theory to add environmental uncertainties in the problem. To solve this problem, we employ the geographic information system to obtain candidate locations of facilities and biomass, and then use fuzzy multiple objective linear programming to solve the problem. From experimental results, the conflict between objectives can be observed.
Most of the production facilities in Europe make use of compressed air to drive equipment for manufacturing and Compressed Air Systems (CAS) account for about 10% of the total electrical energy consumption of European industries. Therefore, reducing CAS energy consumption is a crucial task to meet the European goals of improving energy efficiency and reducing environmental impact of the industrial sector. This work is part of a wider research activity aimed at developing a strategy to optimize the energy use in CAS. In particular, this paper shows the importance of monitoring energy consumption and control energy use in compressed air generation, to enable energy saving practices, enhance the outcomes of energy management projects, and to guide industries in energy management. We propose a novel procedure in which measured data are compared to a baseline obtained through mathematical modelling (i.e. regression functions) to enable faults detection and energy accounting, through the use of control charts (i.e. variations’ control and the Cumulative Sums). The effectiveness of the proposed methodology is demonstrated in a case study, namely the compressed air system of a pharmaceutical manufacturing plant.
Among many kinds of batteries, lithium-ion batteries have become the focus of research interest for electric vehicles (EVs), thanks to their numerous benefits. However, there are many limitations of these technologies. This paper reviews recent research and developments of lithium-ion battery used in EVs. Widely used methods of battery sorting are presented. The characteristics and challenges of estimating battery’s remaining useful life (RUL) and state-of-charge (SOC) are critically reviewed, along with a discussion of the strategies to solve these issues. A new method of sorting retired lithium-ion batteries and estimating the RUL and SOC of the retired lithium-ion batteries is proposed.
The Span and Wagner’s state equation and the segmental design were employed to accommodate the sharp changes of thermophysical properties of supercritical CO2 (S-CO2). The distributions of some important parameters along heat exchanger were discussed. The total entransy dissipation decreases as the coordination between heat transfer rate and temperature difference improves when the total heat transfer rate is fixed and divided evenly, which agrees with the equipartition principle of entransy dissipation. A new dimensionless temperature difference, which comprehensively considers the effectiveness and exchanger area, was proposed without the assumption of fixed thermophysical properties. The new evaluation criterion could represent the ‘efficiency’ of heat exchanger. The present work may be helpful for the design and optimization of heat exchanger using fluids with sharply variable properties.
Air pollution, caused by the use of fossil fuel, has been an environmental plague in China. It has a strong negative impact on human health. Since the costs of damage to health are not born by the pollution producers, these costs translate to social externality. Policies have an important role in optimizing resource allocation, such as penalizing the pollutant producers and incentivizing clean energy development. Among others, replacing coal with natural gas for heating represents an important example of air quality improvement measures. This paper presents a study that evaluates the health impacts from air pollution and the external cost of the “Coal-To-Gas” policy in district heating using Changping District (Beijing, China) as an example. Four scenarios were considered based on the historical and standard PM2.5 concentration. Results show that PM2.5 is responsible for causing an increase of 40% premature deaths in 2015 and that the monetary value of damage to health is higher than 1.2 billion CNY. In 2016 and 2017, the reported air quality was better than that in 2015. As a result, 13.3% and 26% premature deaths caused by air pollution were avoided in 2016 and 2017 compared to 2015 respectively. If the PM2.5 concentration level were to be reduced to national standard, the number of premature deaths attributed to PM2.5 could further decrease to 47.7% compared to 2015. Overall, the Coal-To-Gas policy in district heating reduces 0.017%~0.45% of premature death caused by air pollution each year. Air pollution reduction policies, which are expected to improve air quality together in the future, and the specific policy of Coal-To-Gas in district heating, could make great contribution to reducing the premature death caused by environmental problem and need more attention from the government and the public.
Liquid Air Energy Storage (LAES) attracts much attention to smooth the intermittency of renewable energy and shift the peak load. LAES has many advantages, such as large energy storage density, no geographical constraints, fast response, etc. However, it has a lower round trip efficiency (~50%), compared with other large-scale energy storage technologies (~70%). Based on our previous research, there is a large amount of compression heat which is excess in the LAES. On the other hand, the liquified natural gas (LNG) releases much high-grade cold energy which is usually wasted in the LNG station. Therefore, there is a good integration point between the LAES and LNG. This paper uses the excess compression heat in the LAES and the wasted cold energy in the LNG to drive a Brayton cycle for power generation (denoted as LAES-LNG). The simulation results show that the LAES-LNG system could achieve a high round trip efficiency at ~72%, which is ~31% higher than the baseline LAES and is comparable with other large-scale energy storage technologies. The LAES-LNG system enhances the competitiveness of the LAES and promotes its wide application.
In contemporary architecture, the combination of utilizing passive ventilation and spray-based evaporative cooling technology has been proven to be very effective in improving the interior thermal climate of traditional construction, which has played an important role in advancing the development of green buildings. But the application of this technology in modern buildings has always been limited at best. With the advent of capillary action, a new evaporative cooling method combined with liquid window screen and passive lateral ventilation proposed in this paper, it becomes feasible to cool the air through a liquid capillary window screen, which was developed theoretically by drawing enthalpy diagram, calculating air enthalpy and CFD simulation, providing the theoretical basis and data to support the future advancement of this technology.
In this study, a novel high-efficient energy-saving vacuum BIPV (building integrated photovoltaic) curtain wall, which combines photovoltaic curtain wall and vacuum glazing technologies, was developed and investigated. This vacuum BIPV curtain wall can not only perform on-site power generation, but also significantly reduce the heat transfer through the building envelope with improved thermal insulation. The thermal and power performance of the vacuum PV glazing were investigated by experiments and numerical simulations. A prototype of the vacuum BIPV curtain wall was set up for a short-term outdoor testing to consolidate its thermal and power performance under typical weather conditions of Hong Kong. A comprehensive energy model was then developed to predict the dynamic power and thermal performance of the vacuum BIPV curtain wall to evaluate its annual energy saving potential compared to other advanced window technologies used in buildings in Hong Kong. Based on the simulation model, an optimum design of the vacuum BIPV curtain wall was proposed. In addition, the annual energy-saving potential for a typical high-rise commercial building with the application of miscellaneous BIPV products was estimated using the typical meteorological data. BIPV characteristics were jointly optimized with other passive architectural design parameters and the net building energy demand can be decreased by up to 60% compared with a benchmark office building in Hong Kong. The target of near-zero energy high-rise building can therefore be further approached by this integrated design optimization process.
In order to further promote the development of the new energy vehicle industry, Parallel Management regulation for corporate average fuel consumption and new energy vehicle credits for passenger vehicles (dual-credit scheme) have been proposed by Ministry of Industry and Information Technology in September 2017. This study attempted to investigate the impact of dual-credit scheme on the penetration of new energy vehicles and the short-term strategies of the automotive industry. For this purpose, a market analysis model is proposed based on game theory and the credit market equilibrium to quantify the effects of the credit trading mechanism. Four categories of automakers are considered. The obtained results show that: (i) The dual-credit scheme is indeed an effective policy solution that enables the expansion of the volume of NEV market. (ii) The dual-credit scheme can accelerate the elimination of outdated technologies with lower driving mileage, and it can also promote the adoption of technologies with longer driving mileage. (iii) The dual-credit scheme allows all automakers to achieve their targets in a market efficient manner.
In order to cater for fluctuating energy demand, power plants are designed either as base power plant or peak power plant. The advantage of base power plant is that due to its constant power generation, the power plant has a higher efficiency. To optimize and design a power plant, many previous study has been conducted. Among the studies, Power Pinch tool named Electric System Cascade Analysis (ESCA) was applied to design an optimal power system. ESCA analysis is conducted by assuming that the power plant generates constant power as it is more efficient. However, further analysis using ESCA shows that with a minimal power plant capacity would result in a trade-off that the energy storage system would be larger and leads to higher energy charging and discharging tendency (result in higher energy lost). Considering the time change of heat rate with the corresponding load factor, this study incorporates new algorithm for flexible power generation into the existing ESCA methodology. To validate the new algorithm, an off-grid distributed energy generation system is mathematically modelled and solved. The result from the new algorithm is compared with that of the mathematical model. The comparison of optimal generator capacity shows a difference of 5.71%. The similarity of the result hence validates that the new algorithm is suitable.
