III. WORKING OF SOLAR ASSISTED HYBRID SOLID DESICCANT – VAPOR COMPRESSION COOLING SYSTEM The integrated form of the solar powered solid desiccant – vapor compression hybrid air-conditioning commonly known as ventilation system while it makes use of fresh ventilated (outdoor) air as a process air at the dehumidiﬁer inlet. In ventilation mode, outdoor fresh air is used as process air at dehumidiﬁer inlet. In the process air side of the system conﬁguration shown in Fig. 2 (J.J. Jurinak, 1982), the fresh ambient air stream (state 6) passes through various channels of rotary desiccant wheel. Its humidity is substantially lowered by the desiccant material owing to pressure diﬀerence between it and the vapor in air can be said and the heat of adsorption increases its temperature so that a dehumidiﬁed warm air stream exiting the dehumidiﬁer (state 2). Then it is cooled successively in the heat recovery wheel (2–3), and later in vapor compression cooling coil (3–4) up to the room supply designed comfort conditions. Existing condition (state 5) within conditioned space is also shown . In regeneration side, room return air (state 1) is sensibly heated by passing through heat recovery wheel, simultaneously its pre-cools pas- sing process air on the other side. This is necessary to reduce the re- generation heat consumption. So, the temperature of reactivation air is elevated while coming out from the heat recovery wheel while the humidity ratio is constant (state 7). This heated air is ﬁnally reached its reactivation temperature (state 8) by passing through liquid to air heating coil for reactivating the desiccant material used in the dehumidiﬁer. The hot and humidiﬁed air available after the regeneration process at dehumidiﬁer exit (state 9) is exhausted to the ambient (D.B. Jani et al, 2018).
for 51 % of the total exergy loss. Results also shown that turbine had the highest exergetic efficiency in both configuration. The performance of equipment in both configurations shows that the methane configuration has more equipment with high exergetic efficiency, while the ethanol configuration has more equipment with high irreversibility. Simulated results also shown that the overall exergetic efficiency of the ethanol and methane systems are 24.63 % and 22.33 % respectively, and overall loss work of 1067.36 kW and 783.33 kW respectively indicating that the ethanol fuelled system has the highest rate of irreversibility but conversely also with the highest exergetic efficiency when compared to the methane fuelled system. Economic evaluation of both configurations showed that the capital cost of ethanol and methane system are 8388.56 $/year and 2666.99 $/year respectively indicating that the methane system is more economically viable. Although the ethanol system is more efficient than the methane system, but trade-off between exergetic and economic efficiency favours the selection of methane fuelled configuration over ethanol fuelled configuration for the hybrid SOFC system because the capital cost of the ethanol is far greater than that of methane system.
Like many other fuel cell technologies, SOFCs have a limited load following capa- bility. This is because power transients result in fluctuations in the fuel utilization. Fuel utilization is defined as the ratio of hydrogen consumption by the fuel cell to the net available hydrogen in the anode inlet flow. A high utilization is needed for better efficiencies. Typically, the desired utilization is around 80 to 90% [7, 8, 9]. However, if the utilization is too high, the partial pressure of hydrogen in the fuel cell anode can reduce, causing a voltage drop and irreversible damage due to anode oxidation. This will be discussed in more detail in Chapter 2. So far, SOFC systems have been limited to uniform power applications due to this deficiency. However, recently, there has been an increasing interest in using SOFCs in mobile applications, where respon- siveness is of paramount importance. In this regard, there is an intent to hybridize the fuel cell in order to circumvent one of its largest drawbacks and make use of its many advantages [10, 11], thereby making SOFCs competitive with PEM fuel cells, which have traditionally been considered for hybrid vehicle applications.
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This thesis has been laid out to provide a preliminary platform for mathematical modeling and simulating start ups of hybrid SOFC systems which use heavy hydrocarbons as fuel input to the external reformer. The system has been built around previous models of exter- nal reformer technologies, different types of SOFC configurations and turbomachinery and bottoming cycles components developed in the HySES lab at RIT. A detailed outline of the modeling principles adopted throughout the model has been presented in chapter 2. Mod- eling, based on these principles, of each of the components that constitute the system, has been discussed in detail through chapter 5 and the simulation results have been presented in chapter 6. Due to the lack of published experimental data the results have been treated from a qualitative standpoint. However, one of the most important components of the system, the ATR, has been validated against published data and the results have been found to be sufficiently accurate. Two major improvements over the previous models developed at Hy- SES lab were applied to the models that form a part of this thesis. These are, incorporating phase change phenomenon and capability of handling start-up simulations. In addition a heavy hydrocarbon fuel JP-8, has been modeled. Although published experimental data is not available to model JP-8 accurately, the frame work of the models has been laid out in such a way that in future if published data is accessible, it can be integrated into the model with relative ease.
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required by the breakers to interrupt the fault current, maximum DC breaking current, rated voltage, efficiency and current state of development. These six configurations include solid state circuit breaker, hybrid solid state circuit breaker with mechanical dis-connector, hybrid solid state circuit breaker with fast mechanical switch, me- chanical circuit breaker with LC resonance path and a hybrid fault current limiting circuit breaker. Also a control approach for protection of voltage source converters (VSC) when the fault happens at close to the converter’s terminal is proposed. In the remainder of this chapter, we examine the different grounding methods and system architectures and discuss the design trade-offs in terms of safety, reliability, detec- tion, mitigation, noise, and cost. Moreover, impedance grounding, isolation, and bi-polar architectures are examined and their benefits with respect to these criteria are discussed.
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Magnetically Impelled Arc Butt Welding (MIAB) is a process of hybrid solid-state welding. It suites only for butt joining hollow cylindrical sections such as pipes and tubes. The MIAB welding equipment is robust and it is relatively simple in design, and requires low upset pressures compared to processes like Friction welding. In this process the rotating electric arc is used for heating the extremes of two tubes, which is impelled due to the electromagnetic force created by the interaction of arc current and magnetic field has been generated by external magnetic system. This paper presents the attempts made to design and develop a laboratory MIAB welding module operated hydraulically to realize the principle of the process. Trials are conducted with alloy steel tubes (44.5mmdiameter and 5.5mm, 4.5mm and 3.5mm thickness) by varying the various input parameters and subsequently recording the observations. The experimental procedure involves a series of trials to develop and evaluate the knowledge base for MIAB welding alloy steel tubes. Based on the penetration and bead of the weld the appropriate ranges of various input process parameters identified are presented.
A hybrid solid oxide fuel cell and gas turbine power system model is developed by Chinda and Brault . Two models have been developed based on simple thermodynamic expressions. A comparative study of the simulated configurations, based on an energy analysis is used to perform a parametric study of the overall hybrid system efficiency. Application of the simple fuel cell plants and with integrated gas turbine/steam turbine– fuel cell systems for power generation is reviewed by Choudhury et al. . The analysis shows that the resulting maximum efficiency of this SOFC-combined system can be up to 90% depending upon the operating condition and configuration used. Thermodynamic and dynamic simulation capabilities of hybrid fuel cell gas turbine (FC/GT) combined cycles have been developed and demonstrated by Brouwer . In this work such issues as Design considerations, Cycle configurations, hybrid FC/GT system performance, hybrid system dynamic operation potential and commercialization status have been examined.
than has been observed in other SCO materials [36-39]. The current approach is based upon solid-state hybrid DFT calculations, and includes, we believe for the first time, a separate account of the clamped nuclei and phonon contributions to the dielectric tensors of the HS and LS states. The latter contribution is found to be non- negligible in all cases, and leads to the observation that, while the clamped nuclei term Δε !! ! HS − LS is negative for all axes and functionals, the difference in static
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energy from renewable sources is growing rapidly. One of the major factors of using renewable sources is its negligible contribution towards environmental pollution. Decrement in the number of conventional sources is also a motivational factor towards renewable sources. Among the renewable sources solar and wind are of primary importance. But it is seen that the efficiency of production is less in case of renewable sources. In this circumstance an additional non- conventional source may be used a secondary line of defense. This work is based on a standard photovoltaic system combined in parallel with a solid oxide fuel cell. In this project work a balanced mathematical model of hybrid PV-SOFC system is proposed.
Abstract: Fly Ash (FA) is being utilized as a pozzolonic material when connected as a valuable cementitious material for cement. Fiber Reinforced Concrete (FRC) is a solid having sinewy material which manufactures its helper uprightness. It contains short discrete strands that are reliably scattered and aimlessly arranged. The expansion of Steel Fibers in cement essentially expands its flexural strength; vitality retention limit, malleable conduct before a definitive disappointment, decreased breaking, and improved toughness. Basalt fiber is an elite non-metallic fiber produced using basalt shake dissolved at high temperature. In High Volume Fly Ash Concrete (HVFAC), increment in the amount of cementitious C-S-H stage and calcium aluminium hydrates improves the long haul qualities and lessens the porousness. Therefore improves the solidness properties. The primary point of this examination is to consider the mechanical properties of HVFA cement fortified with half and half filaments. Tests are directed according to the Indian norms and test outcomes are broke down and contrasted and the control example that contains crossover fiber fortified HVFA concrete, HVFA concrete without any strands (non-stringy cement), and Conventional cement. With the fitting understanding of the got outcomes, it is possible to decide the ideal fiber rate in HVFA concrete.
also gives an unbiased estimator, which may however have a different variance. Using the pion as an example, we can demonstrate how positivity is recovered from the truncated propagator. In Fig. 3, we show the effective mass from the truncated propagator and from the hybrid method with a time, spin, colour and space (even-odd) diluted noise vector. The truncated propagator, yielding an effective mass that approaches the asymptotic value from below, is corrected by the addition of the diluted noisy propagator.
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As shown in Figure 17, ASEA Brown Boveri (known as ABB) in Zurich, Switzerland, have proposed hybrid CB for HVDC systems without arcing and without more induction loss . The commutation switch is a semiconductor with very low breakdown voltage, so that the on-state voltage and on-state loss are extremely low. When a fault occurs, the commutation switch will open, and the current commutates to main semiconductor branch. After the branch current becomes zero, the mechanical disconnector switch opens rapidly without arcing, and keeps a long insulation distance. Then main semiconductor switch opens to send all electronic energy to surge arrester bank. The main semiconductor switch as well as the surge arrester bank are series-connected for high voltages, as described at the beginning of this section.
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 B.K. Dey, I. Khan, N. Mondal, A. Bhattacharjee “Mathematical modelling and characteristic analysis of Solar PV cell”, DOI:10.1109/IEMCON.2016.7746318 2016 IEEE.  H. Patel, M. Gupta, “Mathematical modelling and performance analysis of MPPT based solar PV system”,DOI:10.1109/ICEPES.2016.7915923 2016 IEEE.  V. Verda, M.C Quaglia,“Solid oxide fuel cell sub systems for distributed power generation and cogeneration” ,International Association for Hydrogen Energy, DOI: 10.1016/j.ijhydene.2008.01.046 2008 .
In the reentrant cone guided fast ignition scheme, 1 ener- getic electrons produced in high-intensity short-pulse laser- plasma interaction 共LPI兲 have to propagate through tens of micrometers of overdense plasma to ignite the precom- pressed core. Since this problem involves nonlinear laser- plasma interaction, the transport of a huge current 共ⰇMA兲 of fast electrons from the critical surface to the core, and an associated density change of many orders of magnitude, it presents astronomical computational challenges. Even with the state-of-the-art parallel supercomputers, full-scale three- dimensional 共3D兲 fast ignition modeling is still beyond the current capabilities. A common practice is to examine indi- vidual components of the interaction with simplified models. Fast electron generation from the LPI in the critical density region, and their transport in the overdense region, are mod- eled separately using explicit particle-in-cell 共PIC兲 methods and hybrid PIC methods, respectively. Standard explicit PIC modeling of LPI requires an extremely fine mesh 关deter- mined by consideration of the plasma Debye length, D 共cm兲= 743⫻ 冑 T / n, where T is in eV and n is in cm −3 . For
cases, and focusing on the Al sample (delimited by the vertical dashed lines) we clearly see that the collisional losses against target depth do not change while the re- sistive losses increase in terms of both yield and range. This is related to higher resistivity in the regions beyond the shock front. While the collisional losses extend over the entire target due to multiple diffusions, the resistive losses are confined into a more restricted volume around the REB propagation axis, where the current density is the highest. Fig. 4-a) shows the integration of the en- ergy losses over the samples, for the two sample types, warm-dense (open symbols) and cold-solid (solid), as a function of the areal density ρL. While the trends for the collisional losses (green squares) are, as expected, fairly the same, the resistive losses (orange triangles) be- come progressively greater in warm samples compared to cold ones. Beyond ρL ∼ 10.6 mg.cm −2 [vertical dashed line in Fig. 4-a)], they saturate due to the decrease of j h after a certain target depth. Whole beam average
temperatures ( 3 , 30 , 31 ). Decreased OCV at high temperatures was also observed for DCFC based on ceria-gadolinia electrolyte ( 31 ). When alkali carbonate was used as electrolyte, interactions involving the alkali metal in the melt may have contributed to the observed cell potential, which is complicated ( 3 , 28 ). At 800°C, the maximum cur- rent and power densities were 2.2 A/cm 2 (Fig. 2A) and 430 mW/cm 2 (Fig. 2B). This power density is slightly lower than that of the highest DCFC based on the hybrid MCFC/SOFC electrolyte ( 5 ) and MCFC when mixed CO 2 and O 2 was flowing at the cathode ( 25 ), but is higher
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multiphase polymer–solid systems the range of length and time scales may be even broader due to the presence of the inter- faces. For example, concerning the length scales, the behavior of the polymer at the interface is related to the interaction of each atom with the solid surface and typically ranges from lengths of a few (1–2) A, for strongly (chemically) adsorbed ˚ molecules, up to around 1 nm for weakly (physically) adsorbed molecules that interact with the surface via van der Waals (vdW) interactions. In contrast, the behaviour of the entire system is related to the dispersion (i.e. arrangement) of the solid phase (e.g. nanoparticles) in the polymer matrix, which might involve macroscopic dimensions of the order of a few mm. Therefore, at least 7–8 orders of magnitude in length scale are involved in hybrid multi-phase nanostructured materials. Things are even more complicated concerning the relevant time scales of hybrid materials. Atomic bond vibrations (within a molecule or between atoms in a molecule and atoms of a crystal) are typi- cally characterized by times of a few fs (10 15 s), whereas conformational changes associated with dihedral transitions take place in times of the order of a few ps (10 12 s) for temperatures well above the glass transition, T g , and much
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The typical Li ion batteries consist of a negative anode, a positive cathode and a liquid electrolyte. However, many energy storage devices based on combustible organic solvents inevitably carry the risks of leakage, heavier packaging and related hazards. A liquid electrolyte is volatile at high temperature when the battery is charged or discharged quickly or when packs of car batteries are damaged in accidents. Against inherent disadvantages of liquid electrolytes 2 − 3 , solid electrolytes of nonflammable polymers 4 − 5 and all-solid-state
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We have described in Section 5 a method in which the concept of uid impulse of compact support is exploited to match a partitioned vortex sheet which has been created at the wall to closed vortex loops in the ow interior. An alternative approach to modelling the eect of a solid boundary on ow is to model the wall forces directly as \impulse creation". A strategy to express the physics associated with this process can be stated as follows. At time t at some point on the boundary there exists a tangential slip velocity u sl ip . An element of impulse density can be created at this
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In summary, plasmonic nanojets are studied for three diﬀerent types of dielectric concentrators: cylindrical, hybrid linear and hybrid parabolic. The hybrid linear produces the highest electric ﬁeld enhancement factor (edge eﬀect) but at the expense of a divergent exit beam. The eﬀects of diﬀerent metals on the performance of nanojets: the lower are the metal losses, the higher is the electric ﬁeld enhancement factor — thereby it is fair to say that silver works signiﬁcantly better than aluminium in this type of application.