Deciding the location of bio refinery is an important task for management in biofuel supply and demand. This work presents a single-period deterministic model for the optimal location of butanol refinery. The developed model considers a whole system approach for butyric acid supply, butanol refinery and delivery systems. The proposed model determines where and how many refineries to be constructed and components (butyric acid and butanol) to be transported for minimizing the expected total network cost and satisfying regional demand of biofuel. The real scenario of the biofuel demand by region in South Korea is applied to validate the mathematical model. The optimization results will help to determine investment strategies for butanol production.
Microalgae biomass is composed of various bio‐ compounds which can be converted to biofuels. One type of solid fuel which can be derived from microalgae is biochar through torrefaction. However, the production of torrefied microalgae biochar may include environmental impact as it consumes raw materials and energy. A life cycle assessment of the production of torrefied microalgae biochar is proposed in the study using the torrefaction severity index. The results show the electricity requirement of the torrefaction largely contributes to the environmental impact and energy consumption. While the resulting global warming potential of the production of torrefied microalgae biochar using the torrefaction severity index yielded a non‐linear relation.
Over the past two centuries, the research on working fluids drove the tremendous progress of organic Rankine cycle to convert medium- and low-temperature heat into power efficiently. With the increasingly stringent requirements on working fluids, the search for alternative working fluids is a never-ending task. In the present work, a comprehensive review of working fluids selection of ORC is presented to summary the current research results, find out the issues and guide the future developments. The research of working fluid selection is divided into three stages according to research method firstly. Then, the research progress of each stages is summarized. In addition, the research challenges and recommendations for further research of working fluids selection and even for novel thermodynamic cycle are highlighted as well. The results show that for traditional ORC, the optimal working fluid could be selected almost by key parameters such as critical temperature, acentric factor and Jacob number, etc. More importantly, the development direction of novel thermodynamic cycle is presented.
This paper describes the study and research taken under Project oBEMS (Office Building Energy Management System). This is an intelligent hardware and software overlay for office building automation systems based on the advance methods for measuring thermal room conditions. This method allows for managing thermal comfort in certain space by controlling installed Heating, Ventilation and Air Condition system (HVAC) in real time with the use of multisensory map of comfort.
Nowadays, the electrical needs in Indonesia become a very important sector, but the electrification is still at the 6th position in the Southeast Asia region, therefore in 2019, the government aims to increase the electrification to be 99.99 percent. However, it must also be balanced by the increase in the use of New and Renewable Energy (NRE). This is in accordance with the target of the Ministry of Energy and Mineral Resources to achieve 23 percent of the use of NRE in 2025. One of the areas in Indonesia that has the potential for the utilization of applied renewable energy is Diwak Village, Semarang, Central Java. The New and Renewable Energy is the micro-hydro power (MHP). Therefore, this research aims to determine the potential of the microhydropower in Diwak Village, Semarang. Basically, the micro-hydro power (MHP) could be used for an area that has stable water flow discharge and the amount of slope. The methods are calculating float method for flow discharge data, Rock Mass Rating (RMR), and calculating the capacity power. As a result, lithologies at the location are the volcanic and autoclastic breccia. The flow discharge in Diwak River is 0.29 m3 / sec, and the minimum power that will be generated with its discharge is 40.29 KW. These results sum up that the flow has good potential in utilizing MHP in Diwak Village.
Goal commitment is a critical construct in understanding the relationship between goals and behavioral performance in the field of energy conservation. However, little has been done to investigate goal commitment in relation to electricity saving performances in household goal-setting treatment. This paper seeks to re-contextualize the associations of goal commitment with electricity saving performance in households and provide meaningful discussion and explanation to the findings observed. A field experiment was conducted to investigate the effect of goal setting strategy on household electricity consumption in Singapore. In particular, interventions of assigned and self-set goal setting types were compared. Residents’ goal commitment was also accessed to understand the relationship between goals and electricity-saving performance. The results revealed a significant positive correlation between self-reported goal commitment and self-set goal choice. However, no significant relationship was found between self-set goal choice and electricity savings. It was also found that goal commitment has no significant relationship with electricity savings when goal difficulty was not a moderator, as in assigned goal group.
Steam power plants have a huge potential to meet the growing energy demand but its viability has been hampered by its dependence on conventional fossil fuels. One of the ways to minimize fuel consumption and improve effectiveness of thermal power plant is by introducing feed water heaters (FWHs). In this study, thermodynamics performance analysis of a reheatregenerative steam power plant was carried out using CyclePad version 2 software. The impact of the available feed water heaters on the functionality indices of the selected power was examined. Results of the study show that as the number of feed water heater increases from one to ten, the thermal efficiency and boiler efficiency improve from 42.17% to 45.97% and 79% to 96.4 %, respectively. While the fuel consumption, heat rejected to condenser, heat rate and heat input to the power cycle decreases from 9.697 kg/s to 4.686 kg/s, 209.32 kJ/kg to 129.68 kJ/kg, 8536.87 kJ/kWh to 8318.48 kJ/kWh and 361.11 kJ/kg to 237.98 kJ/kg, respectively. This implies decrease in operation cost of the plant and environmental impacts can be achieved by increasing the number of FWHs. Hence, the importance of FWH revamp performance of steam turbine power plant is established.
This study assessed the thermo-economic performance of membrane distillation (MD) for concentrating nutrients and recover process water from digestate at a thermophilic biogas plant. The input data were derived from mapping the Uppsala Vatten och Avfall biogas system, present knowledge on anaerobic digestion process management and technologies for biogas system operating conditions in Sweden. The study evaluated the potential for recovering waste heat from the digestate effluent and boiler flue gas for use in the MD system. The thermal energy requirement, size, and separation efficiency of the MD unit were based on a previous laboratory study. The study assessed the overall energy efficiency and costs estimation of a full-scale codigestion plant with thermally integrated MD. Presented results shows that the proposed model of integrated MD system has the best thermal performance. The recovered waste heat contributed total thermal energy demand of MD and additionally it could save 19% boiler energy by heating incoming slurry. The results showed that the MD product water permeate was 3.5 L/(m2 h) at 65°C digestate inlet temperature. Specific heat demand for MD was 100 kWh/m3 with internal heat recovery. Cost estimation showed that the unit cost of MD permeate water was 3.6 €/m3 at a digestate feed temperature of 65°C. The economic assessment indicated that thermal integration of a biogas plant with MD could be economically feasible. However, long-term continuous studies are needed to determine impact of fouling and membrane lifetime.
In recent years, architectural design with dynamic facade has been more widely introduced as a solution for building environmental issues. From the morphological point of view, this paper attempts to explore the performance otherness of different dynamic typologies during the optimisation of the design process. Take high-rise office building in the tropical region as an example, The two common typologies of rotation and folding are compared and discussed by parameter simulation method with 36 cases in terms of scale, motion and transmittance to find the optimal trade-off between minimising energy demand for cooling and lighting and maximising daylight comfort.
The results of the study show that the energy demand for cooling and lighting can be reduced by 19%- 24% through dynamic façade while folding typology has better performance in energy conservation in all the three orientations. For daylighting, the average daylight comfort area has an increase of 5%-14%, while the value of rotation typology is higher than folding typology. Furthermore, Motion has an influence on the daylight and energy performance except for energy demand of rotation typology. Differently, Transmittance is related to both performances except daylight of rotation typology. This study provides a performance-based approach to dynamic facade selection. A designer could make the decision not only from aesthetic considerations but also combine them to get higher performance.
Research on upgrading of bio-oil in supercritical alcohols shows a potential to produce vehicle fuels from bio-crude. However, the separation of solvent alcohols and upgraded oil remains a problem. In this paper, biocrude derived from fast pyrolysis of rice husk was upgraded in supercritical CO2 with the catalysts of Pd, Ru, Pt (supported on activated carbon), in order to recycle the solvent from upgraded oil spontaneously. Results reveal that increase of reaction temperature promotes both esterification reaction and hydrogenation reaction, while increase of initial H2 pressure promotes the conversion of aldehydes, but decrease the conversion of phenols and sugars. On this basis, the production process of fast pyrolysis and supercritical CO2 upgrading was established and simulated with Aspen plus software. Through life cycle inventory analysis, the environmental impact of this process were studied, and then compared with upgrading in supercritical ethanol. The result shows weaknesses centered in the agricultural production and upgrading process. At last, the analytic hierarchy process is used to consider the weights of various environmental indicators to obtain a comprehensive LCA result. The final results display a slightly better environmental impact potential than that of ethanol.