This study evaluates the concept of developing a non-deform phase change energystorage material possessing higher thermal conductivity and energystoragedensity through pressure compaction process. The theoretical and experimental investigations have shown that the technique is able to reduce porosity and increase conductivity and energystoragedensity of a composite material. Even though there was some measure of plastoelasticity due to decompression, the average porosity was reduced from 62% to 23.8% at a relatively low compaction pressure of 2.8MPa without any structural damage to the tested sample. The mean energystoragedensity increased by 97% and the effective thermal conductivity also increased by twenty five times despite 10% reduction in its latent heat capacity. There is however the need for further
There are many types of energy source that can be obtained from the nature such as wind, sun, fossil fuel and many more. These energy sources are usually stored in energystorage devices like batteries, conventional capacitor and EC. These devices have its advantages and also disadvantages and only suited for certain application depending on their energydensity and also power density. For batteries, it has higherenergydensity but low in power density. Nowadays, researchers focus on the EC to improve their energydensity since its power density and lifecycle was already higher than batteries. There are many factors that need to be considered in order to improve the energydensity of the EC such as type of electrode material and also electrolyte. In this study, carbon material (activated carbon + graphene) was used as an electrode since it’s contributed to a high value of capacitance. Carbon materials such as graphite, carbon nanotube (CNT), activated carbon and graphene oxide are becoming popular to be used as its electrode material. This is due to their special characteristic which is a porous material. To measure the value of capacitance, cyclic voltammetry (CV) method will be used. Before this experiment is conducted, the principle of the CV needs to be known first. There are some variable in this method that will vary the result obtained such as scan rate and voltage window. Furthermore, the uses of CV have not been well discussed before. Besides determining the capacitance, CV can also determine whether the fabricated EC is EDLC or pseudocapacitor, charge/discharge and also its life cycle. So, if EC can increase its energydensity in the future, then the uses of the battery can be replaced.
Improvement in storage is actually achieved by thermal stratification; that is, water of a high temperature than the overall mixing temperature can be extracted at the top of the container and water of a lower temperature than the mixing temperature can be drawn off from the bottom to make use even of short isolation periods and thus running the collector at a higher efficiency. In practice, perfect stratification is not possible since the water entering the tank will cause a certain amount of agitation and mixing. Moreover, there would be a certain amount of diffusion from the entering water (to the stored water) before it reaches the appropriate density level. Having obtained good thermal stratification by eliminating mixing, it is equally important to maintain the temperature layers. Due to the heat losses from the surface of the storage tank, the temperature of water near the vertical walls is lower, leading to natural convection currents that destroy the temperature layers. In order to maintain stratification over long time intervals, the tank should be provided with extremely good thermal insulation or with special installations.
As the v of MALI increases the low frequency permittivity shows a further enhancement when compared to the higher frequency data. MALI shows a flat profile in (62) over the high frequency range 10 kHz -1MHz. As the frequency decreases more polarization mechanisms become active and the permittivity increases steadily to ~ 140 at 100 Hz. Below this frequency the permittivity increases sharply which is attributed to free charge carriers migrating to the sample-electrode interfaces.
4 Table 1.1 shows the differences between battery and EC. Battery and EC are different in power limitation, storage mechanism, energy limitation, charge rate, output voltage, life limitation and even in their cycle life limitation. Battery is used in conventional applications due to its high energy. Unlike battery, EC has a higher power density with longer cycle life time. Recent efforts have been focused on the development of EC that has high power density in order to have a better performance and to be used in a high demand application.
The second novel aspect of this study was higher (27%) myoglobin content was observed in the EBHD type I mus- cle fibres when compared with the ND type I fibres. The higher myoglobin concentrations reported in the EBHD group might be the result of a training induced stimulus. Hypoxia coupled with skeletal muscle activation in both humans (Terrados et al. 1990), diving mammals and rodents has been documented to enhance myoglobin concentration in a muscle-specific manner (Dolar et al. 1999; Kanatous et al. 2008; Kanatous and Mammen 2010; Ponganis et al. 2010). Conversely, (1) hypoxic exposure and (2) skeletal muscle activation in normoxic conditions has been shown to impair these adaptive myoglobin responses (Jacobs et al. 1987; Terrados et al. 1990; Masuda et al. 1999). Thus, the higher myoglobin content observed in the type I muscle fibres of the EBHD group might be the result of a complex interplay between skeletal muscle activation and hypoxia.
According to the European Environment Agency's (EEA) No 6/2009 Technical Report (with the aid of the European Centre for Medium-Range Weather Forecasts), most of the Northern Sea countries and the eastern part of the Mediterranean Sea experience winds with a speed ranging from 4 m/s to 8 m/s or more. Furthermore, the same report states that the previously described areas can provide anywhere from 1000 to more than 3000 full load-hours of potential annually. These areas include some of the most highly populated areas of Europe, where the energy demands are high. They also include some remote islands (particularly in the eastern part of the Mediterranean Sea) where energy independence is crucial for the seamless operation of these communities, therefore harvesting the wind potential-in some cases in a combination with solar energy solutions-promotes energy sustainability, particularly in cases of energy shortage . These findings promote the need to investigate further for efficient ways to harvest the energy provided, especially in areas where the energy demand is high.
From the very beginning, the electrical grid system designers have been aware of the importance of ﬁnding ways to store energy. Most of the methods have been in use for quite a long time, but (apart from pumped water) on a relatively small scale. This was also because fossil fuel is cheap. But the realization that the side eﬀects of massive use of fossil fuel (pollution, possible eﬀect on climate change, and eventually limited supplies), the world has woken up to the fact that we should move to using renewable sources, e.g. wind, PV and biomass. Electrical power from wind and PV ﬂuctuates widely, focusing on the importance of storage, but electrical power and electronic engineering has advanced to make DC-DC, AC-DC and DC-AC conversion highly eﬃcient, and with components readily available many new possibilities are opening up. Economies of scale have made generation of power from renewable sources competitive. This is already a highly dynamic ﬁeld of activity. According to market research, the energystorage market is set to rise to an annual installation size of 6 GW in 2017 and over 40 GW by 2022, from a base of 0.34 GW installed in 2012 and 2013. Over a thousand companies serve the energystorage industry. Pumped water, heat, ﬂywheel, battery and capacitor systems are operating today in the competitive ancillary services power market with fast and accurate response to distribution signals. The market for solar panels —which was less than $200 million in 2012— will be about $19 billion in 2017, and much of the energy produced will have to be stored- at least for a few hours. Energystorage is already big business, and it is set to become much bigger still. One should nevertheless pay attention to other technologies that could aﬀect storage requirements, e.g. by increasing long distance power transmission capacity and smartening the grid.
the limited volume of the caverns. This is due to the hydrogen’s low energydensity per volume of cavern storage. By comparing the storage capacity values of Table 2 with the estimated total of required storage of about 500 TWh in 2030, it becomes clear that, in 2030, about 27,5% of the necessary storage for renewables integration in Europe might be provided by storing methane in the underground salt caverns. Figure 5 shows the relation between the total of storable energy and the round efficiency of the different scenarios. The upper x-axis presents the total time in days by which the European demand for electricity in 2030 could be provided by the energy stored in the salt caverns.
With the increased demand for technologies such as electric vehicles, there is a need to develop high energydensity dielectrics for capacitors which can deliver high power for a short period of time [1-3]. The maximum energystoragedensity, , of dielectrics can be calculated using where is the permittivity of free space, and are the relative permittivity and electrical breakdown strength of the dielectric, respectively. A common way to develop these dielectric materials is by introducing high permittivity particles, such as BaTiO 3 , into a high
Owing to its influence on industrial processes, the energydensity of wood is considered as the most important wood quality index. In sectors, such as steel, pulp and paper, and timber, the energydensity can significantly contribute to the promotion of process gains and changes in product features (Rodrigues et al., 2008). Therefore, it is essential to understand the genetic influence on the type, shape, and cellular organization of wood in order to select eucalyptus genotypes with higherenergydensity. Furthermore, in genetic breeding programs, it is fundamental to establish the correlations between the traits related to the wood quality, because when performing the selection based on one trait, changes occur in the other traits of importance correlated with each other. This is because these correlations do not determine the relative importance of the direct and indirect effects of the traits composing the grain yield (Cruz et al., 2012).
The solution is modelled to include electric vehicles in V2G mode considering the stochastic nature in the arrival and departure of PEV users. To obtain the available energy capacity that PEVs will contribute at every time instance in a day ahead density forecast, the arrival, departure and committed energy during plugin period is modelled as a random variable. The algorithm is modelled to ensure a coordinated and even discharging of available PEV considering each EVs mobility. Furthermore, the algorithm ensures a minimum SOC level is kept for emergency departures at any time. These are realised in conjunction with a day ahead density demand forecast, a given peak limit and characteristic of PEV. The achieved model is then formulated as an optimization problem for a robust schedule resulting in cost saving as well as peak demand reduction while satisfying the technical constraint of maximizing energystorage efficiency and life cycle. The proposed method is then applied to an actual environment in South Korea to verify the performance.
This case study was carried out using a demand-response analysis tool , focusing on a future scenario in which a population’s behavior is unchanged, but the presence of ubiquitous storage enables “peak clipping” and “valley filling”. In the scenario, 15% of households heat their homes and water with electricity; while 70% of households use gas (UK 2003 levels ). Two simulations are run; a baseline simulation using fixed price electricity, and then a simulation including storage effects that are triggered by real-time pricing signals. In the first simulation, all the electrically heated homes have convection heaters for space-heat and small 120- liter immersion tanks equipped with 3kW heater elements that activate just in time to heat water which satisfies hot-water demands. Thus there is negligible energy stored in hot water tanks. Also, there is no battery storage included.
Although many approaches have been developed to synthesize mesoporous silica materials, it is still difficult to apply these methods to the preparation of non-silica mesoporous materials, such as mesoporous carbon and mesoporous transition metal oxides. Among these mesoporous non-silica materials, mesoporous transition metal oxides are important targets, because such solids can combine open d-shells, high surface area, limited wall thickness and open pore networks, with the result that they may exhibit many interesting properties in catalysis, electron transfer, energy conversion and storage, and magnetic devices. 11-17 The first synthesis of a mesoporous transition metal oxide TiO 2 was reported by Jackie Y. Ying and her co-workers in
and in the industrial sector (e.g. process heat and cold). TES systems can be installed as either centralised plants or distributed devices. Centralised plants are designed to store waste heat from large industrial processes, conventional power plants, combined heat and power plants and from renewable power plants, such as concentrated solar power (CSP). Their power capacity ranges typically from hundreds of kW to several MW (i.e. thermal power). Distributed devices are usually buff er storage systems to accumulate solar heat to be used for domestic and commercial buildings (e.g. hot water, heating, appli- ances). Distributed systems are mostly in the range of a few to tens of kW. TES systems – either centralised or distributed - improve the energy effi ciency of industrial processes, residential energy uses and power plants by storing waste or by-product heat or renewable heat when it is available and supplying it upon demand. Thermo-chemical storage systems can also convert waste heat into higher temperature heat or into cold. A number of energy-intensive industrial sectors and processes (e.g. cement, iron and steel, glass) beneﬁ t from TES systems. Manufacturing industry (e.g. automobile industry) can also beneﬁ t signiﬁ cantly from TES. Most importantly, TES can help integrate variable solar heat into the energy system. This applies either to short-term storage based on daily heat buff ers for domestic hot-water production or to long-term heat storage for residential and industrial heating purposes, based on large central storage systems and district heating networks.
One of the major challenges facing the world today is the supply and storage of energy. Climate change caused by global warming is now almost universally accepted as the greatest threat to humanity in the 21 st century. Part of the solution may be rechargeable lithium ion batteries. These devices provide a high energydensity and have resulted in a huge size reduction of hand held electronic devices (laptops, mobiles, etc). If their power capabilities can be improved then they could act as ‘green’ energy stores in devices such as hybrid vehicles. This literature review will give a brief overview of rechargeable lithium battery developments, focussing in particular on inorganic nano and porous materials, the subject of this thesis.
solid condition and belongs to the class of fast ion conduction, which allow macroscopic movement of ions through their structure. These superionic conductors find several technological applications. These applications range from miniature light weight high power density lithium ion batteries for heart pacemakers, mobile phones, laptops computers, etc. to high capacity energystorage devices for next generation. Therefore knowledge of the thermal properties of these materials is most significant. Hence in the present study we have studied phonon dispersion relation, phonon density of states and specific heat of Li 2 O, Na 2 O
This growth in interest in energystorage was recently emphasized in Ontario, via that province’s recent Long- Term Energy Plan, which calls for the procurement of 50 MW of energystorage capacity by the end of 2014. Consequently, an energystorage procurement framework was jointly submitted by the Independent Electricity System Operator (IESO) and Ontario Power Authority (OPA), and supported by the Minister of Energy in the province. The procurement framework allows for a diverse portfolio of energystorage technologies, so as to foster improved understanding of and experience with 1) the services energy storages can provide, 2) the bene- fits they bring to operations and 3) how storage can best be integrated into electricity markets. In Phase I of the procurement framework, released March 12, 2014, the IESO issued a request for proposals for up to 35 MW of grid energystorage capacity from various storage technologies that can provide ancillary and other grid services (e.g., energy time-shifting, transmission congestion relief).