Distributed Layout Research Articles

A parametric study on hydrogen storage in AB5 hydride alloys: Heat and mass transfer, thermodynamics, and design

The design of heat exchangers plays an important role in the performance of solid-state hydrogen storage devices. In this study, three different designs of hydrogen storage devices were investigated, incorporating phase change material (PCM), specifically, RT25HC into their walls in various shapes. A mathematical model, validated using previous experimental data, was employed to calculate heat and mass transfer and determine the reaction time period. The calculations were conducted using ANSYS Fluent, with a constant hydrogen supply pressure of 10 bars and a temperature of 295 K. The absorption properties of the storage reactor were investigated through various parameters such as liquid fraction, hydrogen concentration, and natural convection heat transfer coefficients. Results showed that the geometric structure and PCM distribution significantly impacted the performance of the hydrogen storage devices. Design 1, with a centralized PCM distribution, demonstrated moderate heat transfer rates and a longer reaction time. Design 2, featuring a more distributed PCM layout, improved heat transfer rates and reduced hydrogen kinetics time by 40%. Design 3, which optimized the geometric structure with advanced PCM shapes, achieved the highest heat transfer rates and improved hydrogen kinetics time by 50%. This design also enabled the storage of thermal energy at a high density, ranging from 10.2 J/g to approximately 190.5 J/g. The study provides critical information on the design of efficient solid hydrogen storage processes. The findings suggest significant potential for improved performance in industrial applications such as electric vehicles and domestic energy supply. The high efficiency of the large-scale reactor is due to its well-designed system, which effectively converts chemical energy into thermal energy. Optimizing the reactor geometry and PCM distribution is crucial for achieving superior hydrogen storage and retrieval performance.

Optimising the design and real-time operation of systems of distributed stormwater storages to reduce urban flooding at the catchment scale

The impact of urban flooding is increasing due to the effects of increasing urbanisation and climate change. The use of storages is a relatively well-established approach to reduce peak flows and therefore reduce the need for costly upgrades to stormwater conveyance infrastructure. Recently, real-time control (RTC) has been considered as a means of increasing the performance of these storages. However, previous RTC studies have generally focussed on evaluating RTC with pre-determined storage layouts, i.e., storage locations and volumes, and have ignored the impact of optimising the storage layout. Hence, the objectives of this paper are (i) to introduce a two-step approach to minimising peak flows at the catchment scale by firstly optimising the layout of distributed storages and then optimising their RTC strategies, and (ii) to test the effectiveness of this approach on a real catchment in Adelaide, South Australia. Results show that distributed storage with optimised layouts can achieve significantly higher peak flow reductions than more commonly used end-of-system storage. These range from 5% for 100 m3 of system storage up to 40% for 700 m3 of system storage – whereas end-of-system storage achieved no peak flow reduction for up to 700 m3 of storage. The addition of optimised RTC to distributed storages is able to achieve an additional 10% in peak flow reduction. This increase in performance due to RTC is more significant for smaller system storage volumes. Analysis of the flood hydrographs shows the system peak flow reductions are achieved by attenuating hydrographs at individual storages, as well as delaying hydrographs to reduce their coincidence at the confluence of sub-catchments. These results highlight the potential for using optimised distributed storage layout and RTC as an alternative approach to end-of-system storage to reduce flood peaks.

Capability-based distributed layout formation with or without demand and process flow information

In this paper, a binary integer programming model of an unbiased capability-based distributed layout (UBCB-DL) problem without demand and process flow information is first developed. Then, it is extended to a mixed-integer program for a biased capability-based distributed layout (BCB-DL) problem where the demand information and processing requirements of several parts are taken into account. Since the complex nature of the problems, a recently proposed new generation metaheuristic optimizer namely, weighted superposition attraction (WSA) algorithm is also applied. In order to show validity and practicality of the proposed WSA algorithm and compare its performance with the proposed mathematical programs, a real-life case study is presented. The computational experiments have shown that both of the proposed binary integer program and WSA algorithm are able to find alternative optimal solutions for the UBCB-DL problem under reasonable computation times. However, just a feasible solution with 5.93% optimality gap is found by the proposed mixed-integer program for the BCB-DL problem under 24-hour running time limit. Fortunately, its optimal solution is achieved by the proposed WSA algorithm. Consequently, the proposed WSA algorithm provided the most effective solutions for both UBCB-DL and BCB-DL problems under shortest computation times.

A mathematical model and a parallel multiple search path simulated annealing for an integrated distributed layout design and machine cell formation

Facility layout problem is a well-researched problem of finding configurations of departments and machines on a plant floor with the objective of improving material handling efficiency. With this objective, different techniques of configuring facilities have been documented in literature. Among them are cellular and distributed layouts. Cellular layouts are applicable in scenarios where demand and product mix are relatively stable and rational part families/machine cells can be identified. With this assumption, the literature provides many techniques for their design. Distributed layout, on the other hand, are recommended in volatile environments where product demand and mix are changing very rapidly. However, we argue that a real-life scenario may lay within the spectrum of these two extremes. In this paper, we attempt to bridge this gap by developing a mathematical model that integrates distributed layout design and machine cell formation with an objective to minimize a weighted sum of material handling and inter cellular movement costs. Through distributing the machines over the shop floor, the model attempts to minimize material handling cost. By identifying possible machine cells and part families, it attempts to minimize inter cellular movements. At the same time, the model ensures that machines that belong to the same cell are laid out on contiguous physical locations so that the advantages of cellular manufacturing systems can be fully exploited. Operations sequence, alternative routing, workload balancing among cells and other pragmatic issues are also incorporated in the model. We developed a parallel multiple search path simulated annealing to solve the proposed model efficiently. Several numerical examples are presented to illustrated the model and the computational performance of the developed algorithm.

A mathematical model for the design of distributed layout by considering production planning and system reconfiguration over multiple time periods

In this paper, we develop a new mathematical model that integrates layout configuration and production planning in the design of dynamic distributed layouts. The model incorporates a number of important manufacturing attributes such as demand fluctuation, system reconfiguration, lot splitting, work load balancing, alternative routings, machine capability and tooling requirements. In addition, the model allows several cost elements to be optimized in an integrated manner. These costs are associated with material handling, machine relocation, setup, inventory carrying, in-house production and subcontracting needs. Numerical examples of different sizes are presented to illustrate the nature of the developed model and shed light on several managerial insights.

RE-Based Weighted Distributed Equipment Layout

Recent industry research shows that the existing layout configuration can not satisfy complex manufacturing of many production types. New layout strategy, especially distributed layout received more attention, has the potential to cope with demand interference. This paper attempts to use the method of resource element (RE) to consider equipment production capacity to design weighted distributed layout. Give a more explicit description of unique and common processing ability of devices and parts processing requirements. Considering the weights between REs and make more relevant REs adjacent, using genetic algorithm to construct RE-based weighted distributed layout, minimizing the total weighted minimum distance between REs to minimize material transportation costs.

Capability-based distributed layout and its simulation based analyses

The capability-based distributed layout approach was first proposed by Baykasoglu (Int J Prod Res 41, 2597–2618, 2003) for job shops which are working under highly volatile manufacturing environments in order to avoid high reconfiguration costs. It was argued that the capability-based distributed layout can also be a valid (or better) option for “classical functional layouts” which are generally operating under “high variety” and “low-stable demand”. In this paper first the capability-based distributed layout approach and related issues are reviewed and discussed afterwards the performance of “Capability Based Distributed Layout: (CB-DL)” is tested via extensive simulation experiments. After the simulation experiments, it is observed that capability-based distributed layout has a big potential and can also be considered as an alternative to classical process types of layouts.

Interaction between photovoltaic distributed generation and electricity networks

AbstractElectricity power systems worldwide have traditionally been designed to a vertically connected scheme characterised by centralised generation. Over the last few decades, several factors have dictated a gradual shift from the central‐control approach to a more distributed layout where distributed generation (DG) technologies are effectively integrated and not just connected (appended) to the networks; amongst others liberalisation of electricity markets, security and quality of supply and environmental issues. Photovoltaic powered distributed generation (PV‐DG), although still having a much lesser impact than other DG technologies, is increasingly being embedded into electricity distribution networks worldwide within the framework of successful regulatory state and marketing programmes. PV‐DG has added values (benefits) for the electricity systems that extend from peak power and load reduction (when deployed close to electricity consumption points) to participation in grid‐supporting or grid‐forming modes of operation. The question arises as to what the present situation of PV technology is for its optimal integration in distribution networks, whether there are still technical barriers to overcome as well as new opportunities for PV in future renewably supplied electricity systems. This paper presents the current state of knowledge concerning these topics from a European perspective with regard to different grid structures. It also discusses existing standards, new opportunities to provide grid services and research and development needs identified to fully exploit the added‐value—and still developing—benefits of PV‐DG. Copyright © 2008 John Wiley & Sons, Ltd.

Optical Properties of Surface Micromachining with Randomly Distributed Etch Holes

Optical micromachining or microelectromechanical systems (MEMS) typically require etch holes to reduce the time required to release the micromechanical structure during the sacrificial undercutting. However, high-order diffraction beams generated by the periodic etch-hole array often deteriorate the optical performance by generating noise and erroneous crosstalk signals in most optical systems. In this study, we examined the diffraction from a perforated micromirror and proposed a random distributed etch-hole layout. Due to the superposition of cosine functions with random periods, noise caused by high-order beams can be averaged effectively.

A case for adaptation of the distributed environment layout in multiagent applications

A multiagent application consists of an environment and a number of agents. The environment contains information that the agents use and manipulate to do their work. When a multiagent system is distributed over a number of different hosts (i.e. more than one execution platform is used), the environment has to be distributed as well. The distributed layout of the environment can influence the performance of agents and of the system.In this paper we discuss when a distributed environment can dynamically change its distribution layout. Our focus is on a distributed environment in which mobile agents move around and are aware of the distributed nature of the system.Changes to the layout of the distribution are not only triggered by the agents (like other, application-specific actions), but they can also be triggered by external events, and the environment itself has the ability to pro-actively change its distribution layout over the different hosts when this improves the behavior and efficiency of the application.Using a specific application (solving distributed constraint satisfaction problems) as an example, we indicate the usefulness of changes to the distribution layout and how they can be incorporated easily into a multiagent application design. It turns out that for some problems, the improvement in efficiency can be more than 30%.