Thermal management of large-format Li-ion cells is crucial due to their spatial- and temperature-dependent electrochemical reaction kinetics and heat generation. However, existing battery modeling mostly employs a pseudo-2D model which is not able to capture the local current density and temperature across the entire cell geometry. Therefore, in this paper, we propose a simplified 3D electrochemical/thermal model to investigate the temperature and voltage responses of a Li-ion pouch cell. Concurrently, a lock-in thermography experiment is conducted. The model can achieve good accuracy in predicting the surface temperature and cell voltage of the battery during cycling. A scaling analysis is subsequently carried out to determine the dimensionless numbers that affect the battery performance. The proposed approach helps to facilitate a fundamental understanding of the dominant mechanisms related to voltage polarization, heat generation and temperature non-uniformity.
The prospect of using biomass alone is broad, but there are a number of problems that make it difficult to achieve real profitability. In this paper, the thermal effects and reaction kinetics of cellulose and low-rank coal mixing at different mixing rates (25 wt%, 50 wt.% and 75 wt.%) and different heating rates (10 oC•min-1 , 20 oC•min-1 , 40 oC•min-1 ) were studied via thermogravimetric analyzer(TGA). The addition of low-rank coal can promote the formation of volatile substances in the copyrolysis process, and the degree of synergy is closely related to the heating rate and blending ratio. The kinetic results show that the average activation is 244.44 kJ•mol1 and 164.41 kJ•mol-1 when the low-rank coal blending ratio is 25% and 50%.
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.
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.
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 paper discusses the concept of the sustainable energy ecosystem and introduces the main progress of our solid oxide electrolysis cell research. The latest progress of Power to X (P2X) technology realizes the sustainability of the multi-energy network by introducing the carbon-based cycling procedure. Among the P2X technologies, Solid oxide electrolysis cell (SOEC) is used to co-electrolyze CO2-H2O to produce synthetic gas, which is then synthesized into hydrocarbons through a fetor reactor. These two steps can effectively utilize the CO2 in the atmosphere and realize the carbon-neutral cycle. We focus on the made of Ce0.92Ni0.08O2/YSZ/LSM thin-film batteries at 600℃ for producing syngas. The experiment result shows that the observed current density reaches 0.1 mA/cm2 with a Faraday efficiency of over 95% and a hydrocarbon yield around 4 ml/min/cm2.
The high temperature slag discharged from metallurgical industry has the characteristics of high temperature and large discharge. In 2017, the total amount of liquid slag produced by the world iron and steel industry is about 913 million tons and the amount of waste heat resources contained in liquid slag is equivalent to about 38 million tons of oil equivalent. It has great value of waste heat recovery and resource utilization. Among all kinds of slag treatment methods, dry centrifugal granulation has the advantages of small particle size and high vitrification, which is a developmental slag treatment process. The slag particles produced by centrifugal granulation are typical semimelt and wide-screening particles. This paper reviews the current status of basic scientific research of gas-solid heat transfer, solid-solid heat transfer and phase evolution of semi-melt particles by scholars all over the world. On this basis, in order to achieve efficient waste heat recovery and resource utilization of centrifugal granulated blast furnace slag particles, this paper puts forward specific research contents and technical development ideas about the heat transfer mechanism of semi-melt and wide-screening particles and the hightemperature waste heat recovery technology of hightemperature slag particles.