GRAVITATIONAL ENERGY HARVESTING SYSTEM BASED ON MULTISTAGE BRAKING TECHNIQUE FOR MULTILEVEL ELEVATED CAR PARKING BUILDING
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Different types of high-rise residential buildings have proliferated in different countries at least since the 1940s, for a range of reasons. This paper aims to provide an overview of the current state of evidence on how planning, urban design and architectural aspects of high-rise residential buildings may influence social well-being and mental health. A systematic review following the PRISMA guidelines was conducted. Searches for peer-reviewed papers were conducted in MEDLINE, Embase, PsycInfo, Scopus, SciELO, and Web of Science; 4100 papers were assessed. 23 empirical studies published between 1971 and 2016 were included. The review found that house type, floor level, as well as spaces intrinsic to high-rise residential buildings (e.g. shared stairwells) are associated with social well-being and mental health. However, conceptual gaps and methodological inconsistencies still characterise most of the research in this field. We expect that research about and policy attention to this subject may intensify due to its strategic relevance in the face of global challenges such as increasing urbanization and loneliness. This paper concludes by highlighting a number of recommendations for future research.
This study is focused on the topical issue of increasing the energy efficiency in DC railway systems, in the context of global concerns for reducing the CO2 emissions by minimizing the energy consumption and energy loss. The main achievements in this complex issue are synthesized and discussed in a comprehensive review, emphasizing the implementation and application of the existing solutions on concrete case studies. Thus, all specific subtopics related to the energy efficiency are covered, starting with power quality conditioning and continuing with the recovery of braking energy, of which a large part is lost in the classic DC-traction substations. The solutions of onboard and wayside storage systems for the braking energy are discussed and compared, and practical examples are given. Then, the achievements in transforming the existing DC-traction substations in reversible substations with capabilities of power quality improvement are systematically reviewed by illustrating the main results of recent research on this topic. They include the equipment available on the market and solutions validated through implementations on experimental models. Through the results of this extensive review, useful reference and support are provided for the research and development focused on energy efficient traction systems.
Elevators were reported to cause an important part of building energy consumption. In general, each elevator has two operation states: The load state and power regeneration state. During operation, it has the potential to save energy by using regeneration power efficiently. In existing research, a set of energy storage devices are installed for every elevator, which is highly costly. In this paper, an energy conservation approach for elevators based on a direct current (DC) micro-grid is proposed, which has better economy. Then, an innovative energy-efficient device for the elevator group is designed based on a supercapacitor with similar characteristics and lifetimes. In a high-rise building case study, the experimental test and field data collection show that the innovative approach could result in a high energy efficiency within 15.87–23.1% and 24.1–54.5%, respectively. It is expected that the proposed method and designed device could be employed practically, saving energy consumption for elevator reconstruction.
Permanent magnet motor drive is a widely used technology, offering many advantages, such as exceptional speed, torque control and greater flexibility. Improvement of reliability and efficiency has become a great research interest. Towards this direction and taking into account the major developments in permanent machine technology over the recent years, the use of energy recovery converters has been introduced in various industrial applications. In this paper, the effects of harmonics on a three-phase motor controlled by a drive are analysed, and the behaviours of the filter topology after adopting regenerative drives are studied. The main contribution of this study is a methodology to foresee the standards that can be achieved with the use of an active front end system topology with filters. Moreover, the use of an optimum filter that eases the power system distortion is presented. The analysis presented in this paper is validated experimentally.
As the quantity of direct current (DC) load and wireless power transmission (WPT) devices are continuously increasing in building, in order to efficiently utilize renewable energy (which outputs DC power) such as photovoltaic (PV), especially for building integrated photovoltaic (BIPV), and regeneration energy from elevators (which also outputs DC power), a novel building power distribution system architecture is explored in consideration of the characteristics of supply and demand-side in this paper. The proposed architecture is a hybrid framework integrated with conventional alternating current (AC) power distribution system, DC power distribution and WPT system. The applied AC and DC hybrid power distribution system has higher conversion efficiency than a single AC power system, which indicates that the former is becoming an important trend of building power distribution. In addition, the results of experimental test in a case study suggest that the proposed architecture can provide fine service for efficient application of renewable energy and regeneration energy in building. The obtained results also can serve as a foundation to promote the development of building power distribution system and related practical application in building.
Energy efficiency is a crucial issue towards long-term deployment of compliant robots in the real world. In the context of variable impedance actuators (VIAs), one of the main focuses has been on improving energy efficiency through reduction of energy consumption. However, the harvesting of dissipated energy in such systems remains under-explored. This study proposes a variable damping module design enabling energy regeneration in VIAs by exploiting the regenerative braking effect of dc motors. The proposed damping module uses four switches to combine regenerative and dynamic braking, in a hybrid approach that enables energy regeneration without a reduction in the range of damping achievable. A physical implementation on a simple VIA mechanism is presented in which the regenerative properties of the proposed module are characterized and compared against theoretical predictions. To investigate the role of variable regenerative damping in terms of energy efficiency of long-term operation, experiments are reported in which the VIA, equipped with the proposed damping module, performs sequential reaching to a series of stochastic targets. The results indicate that the combination of variable stiffness and variable regenerative damping results in a
performance improvement on metrics incorporating reaching accuracy, settling time, energy consumption and regeneration over comparable schemes, where either stiffness or damping are fixed.
Electric rail transit systems are the large consumers of energy. In trains with regenerative braking capability, a fraction of the energy used to power a train is regenerated during braking. This regenerated energy, if not properly captured, is typically dumped in the form of heat to avoid overvoltage. Finding a way to recuperate regenerative braking energy can result in economic as well as technical merits. In this comprehensive paper, the various methods and technologies that were proposed for regenerative energy recuperation have been analyzed, investigated, and compared. These technologies include: train timetable optimization, energy storage systems (onboard and wayside), and reversible substations.
This paper presents an investigation on a distributed regenerative braking system for freight trains. The system, which involves installing regenerative braking units on the bogies of freight rail wagons, is proposed in a patent by Transnet SOC Ltd. The system allows for numerous regenerative braking systems to be installed on a single freight train in a distributed manner, which collectively function together to perform regenerative braking on the train to reduce the energy consumption of the train. The proposed system would, if implemented successfully, alleviate challenges and limitations with current regenerative braking systems on diesel-powered freight trains. The goal of the investigation is to determine whether the system is both technically and economically feasible. The proposed regenerative braking system is conceptualized in this study by first establishing the requirements of the system from in-service train data, followed by the development of the subsystems and major components based on existing technology. A physical system simulation model is subsequently developed to establish the energy savings performance of the system concepts for typical freight train routes. The results show that energy savings of between 10% and 24% can be realized. This demonstrates the technical feasibility of the proposed system. Next, the proposed system and the candidate concepts are evaluated in economic terms by means of a cost–benefit analysis. The decision criteria calculated in the cost–benefit analysis provide unanimous results as to which of the candidate concepts are economically feasible. It is shown that four of the candidate concepts, all utilizing the same transmission topology incorporating a continuously variable transmission with different flywheel configurations, are economically feasible. It is therefore concluded that the results of the cost–benefit analysis indicated that the proposed distributed regenerative braking system for freight trains is economically feasible and could deliver favorable financial returns if pursued.