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High-speed medium-voltage (MV) adjustable speed drives (ASDs) are essential for gearless direct drive systems, offering reduced size and maintenance. High-speed applications include off-shore compressors in oil and gas industry, wind energy generation, and fly-wheel energy storage systems. This paper will cover the implications to cover a higher speed range (120-500Hz), arising from retrofitting existing MV 50/60 Hz cascaded H-bridge (CHB) ASDs. An essential requirement for the ASD is to remain within the Total Harmonic Distortion (THD) and Harmonic Voltage Factor (HVF) constraints set by standards. Key-aspects affecting CHB performance at high speeds are switching frequency and number of voltage levels. Another key-aspect is the CHB power cell DC-Link operational stress, power loss, and size. A unique comprehensive analysis covering all mentioned aspects is performed to provide a view of the MV high-speed application demands and needed High-Speed CHB design considerations.

In India, e-rickshaws today are an established last-mile commute mode transcending the status earlier held by internal-combustion engine-based auto-rickshaws. With various state governments in India legislating policies in favor of this mode and offering monetary incentives to the e-rickshaw drivers (ERDs) and charging service providers (CSPs), the future of e-rickshaws in India is bright. However, in technical terms this mode falls short of the lifetime it is supposed to sustain. The premature failure of e-rickshaws comes from the technical glitches in the powertrain and the battery which is subjected to constant peak stresses. To resolve this issue of e-rickshaw life, an efficient ultracapacitor/battery-based e-rickshaw system is designed in this article. The system is designed on Matlab/Simulink and simulated with a bidirectional DC-DC converter, valve-regulated lead-acid (VRLA) battery, ultracapacitor (UC), and a BLDC motor. Moreover, a comparative analysis of two different control strategies namely, Proportional Integral Derivative (PID) and Artificial Neural Network (ANNET) is carried out on the Simulink platform. The results from the analysis of the designed system augment the e-rickshaw system's efficiency and corroborate an increase in its life.

With increasing fuel costs, pollution and climate change, the public have developed a greater awareness of efficient energy usage. It is well known that the Internal Combustion Engine on light passenger vehicles are very inefficient during start/stop periods. To increase the efficiency, lower emissions and running costs, an electric drive design is implemented as a retrofit to a pre-existing automobile. It is evident that there are many purpose-built hybrid electric cars in the market. However, there is a lack of retrofit systems for millions of pre-existing Internal Combustion Engine vehicles. The design concept presented in this paper includes the use of two Brushless DC electric motors specifically designed to fit as hubs for the rear wheels of the vehicle and powered by an on- board battery bank. Test results are presented on aspects such as performance and economics leading to comparisons between with and without the retrofit design. The paper demonstrates what performance and savings can be achieved by retrofitting wheel hub motors to a front wheel driven car with an IC engine

In city contexts it is common to encounter entire urban districts with poor energy performances buildings, where urban and building retrofitting can be carried out ranging from light to radical transformation. Taking into account that the Clean energy package for All Europeans, which defines European climate and energy policy beyond 2020, encourages the Member States to develop policies, financial measures, and other tools for the promotion of strategies that can lead to building renovation, this paper wants to provide a multi-energy planning methodology for an entire urban neighborhood. The development of a district's multi-energy smart grid has been planned with the objective of increasing the local production from local renewable thermal and electrical energy to decrease the gap between energy production and consumption of the district. The investment cost is considered as objective for multi-energy system optimization. The proposed methodology is applied to an existing urban district in the City of Cagliari (Italy) considering different retrofitting scenarios. The simulation results show the effectiveness of the proposed methodology.

In practice, large steam turbine is often with high energy consumption after long operation time, whose efficiency cannot reach the designed value only through the overhaul of the cylinder. Therefore, it is necessary to carry out a comprehensive upgrading and transformation implemented by considering actual thermal and electrical load demand. Firstly, the internationally advanced flow-through technology must be used to optimize the cylinder block through-flow, which improves the power generation efficiency under the condition of pure coagulation. Then, the retrofitting strategy of double-rotor heating with high back pressure is adopted to actual heating development in the future. Thus, the goal of maximum enterprise benefits is achieved. Taking a typical supercritical 670MW unit as an example, the increase of unit's maximum output is 10MW and the heat consumption rate in THA condition reaches 7545.lkJ/kW.h after transformation. It has a certain practical reference value.

This paper introduces an internet-of-things (IoT) based economic retrofitting setup for digitising the analog water meters to make them smart. The setup contains a Raspberry-Pi microcontroller and a Pi-camera mounted on top of the analog water meter to take its images. The captured images are then preprocessed to estimate readings using a machine learning (ML) model. The employed ML algorithm is trained on a rich dataset that includes digits from the images of water meters captured by the hardware setup for ten days. The readings are posted on a cloud server in real-time using Raspberry-Pi. High temporal resolution plots of flow rate and volume are generated to derive inferences. The collected data can be used for deriving water consumption patterns and fault detection for efficient water management.

Transformers are one of the most essential electrical equipment in a substation, assessing their seismic withstand capacity is of great significance to sustain the normal function of substation. To evaluate the earthquake resistance performance of a 500 kV transformer, a finite element model of a whole transformer system composed of tank, turrets and bushings was first established. And dynamic properties and time history analysis were carried out to find its most vulnerable points. Then seismic vulnerability analysis can be conducted using the incremental dynamic analysis (IDA) method. Results show that the dynamic amplification of the tank and turret to the bushing is much larger than the threshold of 2.0 specified in the relevant codes, and the root section of the high voltage (HV) bushing is the most vulnerable and it is not likely to be acceptable for the ground motions with a peak ground acceleration (PGA) of 0.3 g, which is even less than the local fortification intensity. Therefore, the influence of transformer tank and turrets can not be ignored when evaluating the seismic performance of a transformer bushing, and some retrofitting measures should be taken to enhance their seismic withstand capacity.

Sustainability and environmental matters are two important discussion topics at present. Some other important issues, e.g. the use of energy, are related to sustainability matters. In order for a country to develop and grow economically, energy is a significant element that is mostly used in buildings and the problem is that they waste the energy especially in public buildings such as libraries. As a result, analyzing and retrofitting energy consumption in public buildings is the purpose of the present research. It will be done by applying Building Information Modeling (BIM) software with the aim of reaching comfort level and energy management. BIM software was applied in a case study and with the help of the energy analysis software then the analysis was carried out. Improving the efficiency of energy consumption was made possible, through identifying and changing the present patterns of energy usage. With the aim of changing the materials, internal design and the building's comfort level, a practical method was suggested in this case study which resulted in a safe temperature for books, a comfortable temperature for users, in addition to energy preservation of up to 25%.

Nowadays, in the process of rebuilding old communities, we still face various difficulties such as financing and negotiation. One of the reasons is the lack of green retrofitting awareness of residents. This study tries to develop a green retrofitting evaluation framework that is used by the residents so that they know the renovation problems the community has encountered. Through expert interviews and literature reviews, the criteria and the sub-criteria in each criterion in the retrofitting evaluation framework were developed first. Then, the Delphi expert questionnaires were used to determine the final evaluation framework, which consisted of five criteria and eighteen sub-criteria. The five criteria were energy utilization, water use, waste minimization and recycling, public facilities, and ecology. Thereafter, the Analytic Hierarchical Process (AHP) was used to understand the importance of each obtained sub-criterion by finding its absolute weight. Finally, each factor was applied to an old community in Zhangpu County, Fujian Province, China to diagnose the renovation problems encountered and the renovation strategies were proposed using available green energy conservation technology.

Nowadays, automation systems for naval propulsion groups with gas turbines use programmable logic controllers for a precise and reliable control. The automation system is designed so as to be able to connect using signal cables to the transducers monitoring the engine’s parameters, via adapters, so that the command and regulation functions to be fully automatized. These signals are managed by means of the software program implemented in the PLC, and subsequent data acquisition. One of the important problems is the available resource of the propulsion group, until capital repair is required. The remaining lifetime depends on the operating regimes of the gas turbine engine. This problem is more pronounced in the propulsion groups equipping navy ships, where the dynamic regimes of gas turbine engines are much more demanding, and hence the pre-established operating limits may be exceeded. The automation configuration presented herein ensures the accurate computation and precise control of essential parameters for which the direct measurement is not possible using transducers. These parameters are the exhaust gas temperature, the power developed by the engine and implicitly the torque developed at propeller shaft.

Aim of the publication was to show the process of designing, building, and programing a device for cleaning gutters. The publication describes the issue of engineering education. The task of the work is to make the entire structure in 3D printing and retrofitting with standard elements. During the analysis, the focus was on the implementation of the device with the longest possible operating time without the need to recharge and adapting the device to the easiest access to spare parts to modify the components to be more effective. The publication presents the results of engineering education in the field of computer science and information technology.

This paper presents the design directions for Ecofitting, a sustainable solution for the large UK fleet of internal combustion engine cars that will soon be rendered non-compliant with fast approaching initiatives for Ultra Low Emission Vehicles. Ecofitting circular economy strategy goes beyond just electrification, opening an opportunity for new approaches to automotive design, and to cater for generational shifts in desirability. State-of-the-art, taxonomic and trend mapping research have identified opportunities for retrofitting leading to four proposed design directions inspired and influenced by sustainable practices across other industries, that directly involve the consumer, and provide an alternative approach to the longstanding aesthetic of perfection historically seen in vehicle design.

Demand in unmanned aircraft (UA) technologies for real-world applications have increased over the recent years, driving national aviation authorities to implement weight dependent regulations across all UA operations. Introduction of registration for UA weighing 250g and above as well as other regulatory requirements for heavier UA systems have motivated manufacturers to consider weight as a part of design requirement. Although UA weight is not a major concern for most outdoor applications, weight requirements imposed by aviation authorities further emphasizes the importance to develop smaller and lighter UA for safer indoor or urban operations in GPS denied environments. Comparison across various sensors used for autonomous UA navigation methods suggested that benefits of using vision sensors outweighs other methods since most UA are equipped with onboard cameras and thus does not require retrofitting of additional hardware. In addition, vision sensor data can potentially be used for both navigation and non-navigation tasks resulting in a productive and lightweight UA system that is able to avoid or reduce regulatory burdens for GPS denied UA operations.

To tackle the massive drivers of global warming, which are our buildings, especially existing buildings, we need to work on making these buildings more energy efficient. Building retrofitting in Palestine can tackle the issue of energy poverty resulting from a shortage of natural resources and the dependence on imported energy. This paper aims to use energy simulation for typical existing residential buildings to assess the energy saving from a proposed retrofitting program. The most frequently used residential building types were selected for the computer simulation assessment of the energy retrofitting program. The energy use of those selected residential buildings has been identified and a base case has been established as a baseline for the energy retrofitting evaluation. Three levels of retrofitting programs were applied for the selected buildings. A Simulation model was created for the current residential building type using the DesignBuilder tool to evaluate the savings from applying the retrofit program. The simulation has been done for one climate zone in Palestine. The results show that the main energy consumption in the typical households are water heating, room heating, cooling and electric lighting. The results show that level one measures results in a 16.7% reduction in energy consumption due to reducing the heating and cooling. Level two results in a 13.3% reduction in energy consumption for heating, cooling and lighting. At level three further 28.9% reduction in the total energy consumption can be achieved for heating, cooling and water heating. The total saving from energy consumption can reach up to 58.9% of the total energy consumed in existing residential buildings by applying the three levels of the energy retrofitting plan.

This research paper is exploring the possibility of retrofitting one selected residential apartment in Amman, Jordan. While the green building is exclusively conducted for commercial companies and foreign organization, there are no information for residential site within buildings unit. The study provided systematic analysis and energy and water consumption. Since water and energy sectors in Jordan suffers from several major problems, a systematic solution from induvial people is proposed. Therefore, this study suggests various modifications and retrofitting in one single apartment, then I apply them and recording the differences based on the LEED rating system.

In the course of the fourth industrial revolution, companies are facing considerable challenges, such as retrofitting and integrating existing, mission-critical automated production systems (aPS) into new interconnected environments. To integrate the production data from aPS and to make it available for data analysis and plant monitoring, relevant data from the programmable logic controller (PLC) of each aPS needs to be accessed and forwarded. These PLCs, at a first priority, control the production plants and ensure reliable production. Due to the long life-cycles of aPS of around 30 years, a huge number of legacy PLCs with limited processing and communication capabilities exists in the field. Therefore, retrofitting concepts that aim to allow access to PLC data need to account for this special, mission-critical role of PLCs. In the context of PLC retrofitting approaches, research currently addresses two domains: on the one hand, abstract Industrie 4.0 architectures are proposed that lack of implementation details. On the other hand, specific retrofitting concepts are presented, which are usually not transferable to other application purposes.Hence, this work aims to fill this gap by deriving generally applicable retrofitting strategies for legacy PLCs for data collection. Five technology-neutral retrofitting concepts based on industrially relevant use-cases were proposed. Three concepts were substantiated on an exemplary basis and their validity shown within a proof-of-concept. Altogether, this work can act as a guideline for retrofitting automation technology to facilitate the integration of legacy systems in Industrie 4.0 scenarios.

Industry 4.0 describes a concept where machines and systems are smart and interconnected. Production processes can be monitored, optimized and the failure of individual components can be predicted. While it may be possible for big companies to plan a new, smart and interconnected production facility on the “greenfield”, this is hardly realistic for small and medium-sized enterprises. Due to the long deployment duration of production facilities, alternative approaches must be identified to upgrade the existing machines and systems with sensor technology, software and IT connectivity. This process is called retrofitting. Nevertheless, no universal solution exists on the market that meets the requirements for all use-cases. Moreover, small and medium sized enterprises in general do not have the abilities and the knowhow to develop and manufacture these complex and tailored solutions in small lot sizes, which is an essential requirement for retrofitting. Standard shaped sensors cannot be used due to the individual installation situation in the machines. 3D Mechatronic Integrated Devices (MID), a generic term for distinctive spatial integration technologies breaks through the known limitations of printed circuit boards and enables the development of new highly innovative products. The most common form to produce MIDs are injection molding based. While this production technology is state of the art for high quantities, it is too expensive, time-consuming and complex for smaller batch sizes. Additive manufacturing technologies (AM) provide an attractive approach to this problem. AM allows a faster reaction to product changes, is more cost efficient in small quantities and allows a higher degree of freedom in product design. The combination of MIDs and AM not only fulfils the requirements regarding costs and flexibility but also enables the creation of new, highly individual and electrically functionalized products in general. In the context of this paper, three additive technologies are evaluated with respect to their applicability against the background of different retrofitting applications. A focus lies on the creation of 3D shaped circuit carriers. Based on different use cases in the context of retrofitting applications the benefits as well as the restrictions are pointed out and their utilization is evaluated.

This retrofitting (electric conversion) project aims to modify the present structure and mechanism of Autorickshaw to make it suitable for its electrification, rather than designing a complete new E-rickshaw. This paper discusses study on feasibility check of project, selection of design parameters, validation of selected design parameters through MATLAB simulations and selection of most important devices for retrofitting i.e. traction motor and battery. Inspiration for the project is that thousands of auto rickshaws are been scrapped each year in Mumbai itself because of malfunctioning IC engine, which is a huge loss for rickshaw owners if scrapping is done before end of lifespan viz. 15 years. The old scrapped chassis and body of CNG auto rickshaw was reused to support the tagline “generating best from waste”. The BLDC motor has replaced the heart of auto rickshaw, IC engine, and the electricity of storage battery replaces the fuel and a controller is used for proper functioning and control of auto rickshaw. All this system was tried to be simulated, wherever and whenever possible by using MATLAB, and load test on motor.

Renovating and updating office buildings to green buildings is an important measure to solve environmental problems. As focusing on improving the green performance of existing office buildings in China, this research is to develop and establish a green retrofitting assessment framework for their renovation diagnosis and rehabilitation of the existing office buildings. Through literature reviews and expert interviews, the major indices and the factors of the indices in the initial green retrofitting assessment framework were determined. Afterward, the Delphi method was used to finalize the assessment framework with the data of the expert questionnaires. The final assessment framework consisted of five indices and seventeen factors. The five indices were energy conservation, water saving, waste reduction, physical environment, and ecological protection. To easily apply the assessment framework to the existing office buildings, a renovation diagnosis and rehabilitation scoring table were established by using an analytic hierarchical process (AHP) to determine the relative weights of the issues and the factors. Finally, the scoring table was applied to an existing office building in Fuzhou City, Fujian Province, China to investigate the retrofitting diagnosis problems and propose the retrofitting strategies using available engineering and technology.

The most critical yet a common issue in terms of thermal comfort in hot or warm climates is found to be overheating of the indoors. Most popularly, active thermal modification systems are adopted to overcome this issue, even though they are less environmentally friendly. In order to find solutions, this research investigates the possibilities of integrating the principles of thermal mass effect, structural cooling plus nocturnal cooling effect, and stack effect, to develop a sustainable cooling technique for warm climates, using clay. The emphasis is to develop a dynamic clay secondary wall panel system that sucks indoor hot air and removes it to the outdoors whilst enhancing the cooling of the indoors at the same time, and which also complies with aesthetic or architectural purposes. The methodology of the research involves identifying the material’s best mix proportion for the finest inner porosity and air permeability, identifying the simplest practical casting method of the panel, optimum configurations of the perforations (pore distribution, pore size, the buoyancy of the pores), the best suitable firing temperature and the firing time, and the applicability of the panel for indoor air temperature reduction. The results show compliance with known principles and reveal the possibility of amalgamating them for better indoor heat reduction. It is suggested that the invention is applicable from low cost to high-end construction projects, as well as new and retrofitting.

Advancement in Satellite Technology has helped better comprehend how light interacts with land surfaces and other physical objects. By remotely monitoring land cover in identified region, the usage and changes occurring due to various natural and man-made events can be visualized. This paper studies the influence of retrofitting programs like Smart City Mission (Government initiative) and Green Saviours (an NGO) on the land usage changes for Belagavi district from January 2017 to date. This is achieved by acquiring Vegetation Indices (VI) from the sentinel-2 data and identifying various classes for the region under focus. Belagavi city being the region of research, the results compare the two VI(s) i.e., NDVI (Normalized Difference Vegetation Index) & NDWI (Normalized Difference Water Index), using which the effect of retrofitting programs like smart city is observed. The ground truth results are compared with the calculated kappa co-efficient. They indicate a moderate increase in the built-up area since January 2017.

Electrical Energy is one of the most common forms of energy in the world. Due to the increasing socio-economical style of living, the demand for electrical energy is increasing at an unprecedented rate, which transducers to high emission of greenhouse gases due to the combustion of fossil fuel. Two approaches can be applied to mitigate the emission; increased use of renewable sources of energy or retrofitting existing systems with technology. The latter was explored in this study. Predictive analysis was employed to predict the load demand for a typical Mauritian household. Fuzzy Time series and Probabilistic Neural Network were considered as predictive models and were modelled in KNIME Platform Analytics. It was found that Probabilistic Neural Network was more appropriate for the load demand prediction yielding a Mean Absolute Percentage Error of 3.5 % as compared to the 4.7 % for Fuzzy Time series.

In Germany and many other countries, recyclable wastes like waste glass are disposed of at centrally placed collection containers. Efficient and demand-based emptying of these containers requires knowledge about their actual filling levels. This paper aims to propose a solution for determination of filling level of waste glass containers by retrofitting them with cheap and easy to install sensors, glued onto the outside of such. These sensors will feature an accelerometer to record the vibrations which occur whenever waste glass is disposed of. The recorded vibrations are transferred via NB-IoT to a cloud infrastructure where a not yet specified analyzation and determination of the individual container filling level could be performed.

Present-day buildings are designed to be occupant-centric- they predominantly focus on occupants’ comfort, health, safety and productivity. Maximising occupant comfort while managing energy costs are the important aspects of smart buildings. Industry and academia have largely contributed towards the development of comfort management systems for buildings. The solutions thus provided are mostly proprietary and/or expensive. They may not be easily adaptable to changes that arise due to the demographic factors and location of the building. Furthermore, the inflexibility of these solutions might not allow retrofitting. With these challenges at hand, it becomes important to investigate the design and development of easily adaptable, scalable and low-cost solutions using open-source platforms available today. In this paper, an architecture of a prototype for a comfort management system is presented, using the open-source Elasticsearch, Logstash and Kibana (ELK) stack. A practical case study of thermal comfort management, based on an existing theoretical budget-constrained model, has been explained. Discussion on extension of the system to accommodate other comfort dimensions has also been included.

The increasing sensibility to the environment protection and emission reduction in the atmosphere is also influencing the maritime shipping. The more restrictive regulations on pollutants suggest the adoption of alternative onboard propulsion and energy generation systems. To this end, electrification is a promising solution for pollution reduction, giving some flexibility on the strategy to use for the onboard system. Moreover, a hybrid-electric system can be combined with the exploitation of green fuel, increasing the potential reduction of total emissions. However, the final efficiency, both in term of emission reduction and expected operative expenditure, is strongly influenced by the operative profile of the vessel. This is of utmost importance both in case of a newly designed vessel and in the retrofitting of an existing one. In the present work, the impact of electrification on a double-ended ferry is presented, taking into consideration the operative profile of the vessel derived from real navigation data.

With the advent of semiconductor technology in power system the variable speed machines have become common practice world over. In the beginning, variable speed drives were mainly cyclo-converters. With the growth in semiconductor technology, IGBT, IGCT etc. based variable speed drives, offering better control & efficiency over wide range of operation of the machine, are available now. Tehri PSP has the credit of employing the first variable speed machine in India. However, some pumped storage plants undergoing retrofitting are also opting for variable speed machines now. In this paper an attempt has been made to analyze the model study data pertaining to the prototype of Tehri PSP machine to illustrate the advantages of variable speed machine over the fixed speed machine.

The optimization of energy usage, improvement of energy efficiency, and lowering the carbon footprint are today’s hot topics in many fields of research. Research shows that in many countries the cooling and heating of buildings can consume significant amounts of energy. For example, in Finland the heating of buildings uses over a quarter of the total energy produced. Furthermore, most of the older, existing buildings lack any means of measuring indoor conditions and are rarely equipped with systems capable of adequately controlling the conditions within working or living environments. Commercial products do exist for monitoring larger buildings or building complexes, but these tend to be quite expensive and in many cases are targeted for use in newer, so-called “smart buildings”, and may not be directly applicable for retrofitting into older buildings. This paper presents an ongoing research study that aims to use cost-effective, off-the-shelf components for measuring indoor air quality with the ultimate goal of utilizing the collected data for optimizing energy usage in existing building stock while preserving good living and working conditions. The paper introduces the overall system architecture and describes the components used in implementing the sensor system. The use of the system is illustrated through two use cases: a university classroom and an apartment building used for eldercare. The requirements that were observed for the system as well as the experiences and challenges faced in designing, implementing, and installing the system in real-life locations are discussed in this paper. acceptedVersion

Curved major structures will get cracks and it will be costly and difficult to replace. So retrofitting technique in this paper will enable the engineers to retrofit these beams without replacing them. This experimental study aims at investigating the behaviour of damaged curved Reinforced Concrete (RC) beams strengthened with Carbon Fiber Reinforced Polymer (CFRP) sheets. Two sets of curved RC beam specimens, with 4000 mm radii were used. The beams were pre cracked and repaired by using epoxy grout prior to strengthening. The beams were retrofitted using an alternative bond arrangement of Near Surface Mounted (NSM) CFRP sheets. The specimens were tested under four-point bending test method. On average 51% increase in flexural gain was observed from retrofitted beams with respect to non-cracked control samples.

It is well known fact that masonry structures suffers extensive loss during earthquakes, leading to notable damage of lives. Majority of structures in India are Un-Reinforced masonry (URM) which are not strong and vulnerable under moderate earthquakes. Masonry construction remains vulnerable to seismic force due to many reasons like lack of integral action between brick and mortar, low shear strength of masonry, heavy mass and varying construction practices. Therefore, it is essential to increase seismic resistance of masonry structures utilizing dissimilar retrofitting measures. Past earthquakes in India and other countries reveals low seismic resistance of URM structure and extensive damage caused. Reconstruction of damaged structure may be very costly and time consuming therefore retrofitting is the best alternative to enhance the seismic performance of damaged structures. Many conventional and non-conventional techniques like, using ferrocement, shotcrete, steel elements application, grout injection, FRP, post-tensioning are available around the world for restoring the structures. This paper provides analytical work and finite element simulation of unreinforced masonry dome retrofitted using carbon fiber reinforced polymer (CFRP) or steel plate jacketing. The behavior of retrofitted structure is studied numerically. Dome structure have been analysed using commercial software SAP 2000. The structures have been analysed for gravity and earthquake loadings. Dome models have been analysed numerically using the time history data of 1999 Kocaeli earthquake while R.C. C frame is analysed by response spectrum method. Dome structure is retrofitted using steel plates and CFRP at the support level as well as tension zone. Analysis reveals that shell stresses are significantly reduced which may range from 10 percent to even 50 percent depending upon arrangement of retrofitting material for dome structure. Stress reduction can be observed significantly at the support level of the dome models.

This work demonstrates the possibility of retrofitting the AC home appliances for direct usage in DC microgrids using simple and low-cost methods. Nowadays, most of the appliances are using AC-DC conversion, which creates the possibility of direct connection of home appliances to DC voltage grids. The paper shows the practical results made on an air conditioning/heat pump system, an induction heating cooker and a refrigerator by retrofitting to a 350V DC grid.

Current policies addressing the energy efficiency of buildings aimed at the control of their overall primary energy demand, require not only that the edifice envelope has to be properly designed to optimize its thermal performances, but also that the eco-friendly properties of the involved building materials have to be properly taken into account, in order of assessing all the associated environmental costs. In fact, the design of envelope structures that are able to realize proper levels of thermal insulation and, in the same time, to employ materials characterized by low environmental impacts, are believed as the most effective strategies to be adopted in the aim of addressing the above-mentioned issues. In this regard natural materials, such as vegetal fibres or materials derived from the recycling of industrial/ agricultural waste, reveal very attractive characteristics. Indeed, recent studies on the use of natural materials in buildings concentrate on raw materials deriving from either agriculture, waste, or recycling processes. Such topics are the focuses of the present analysis. Specifically, this paper intends to provide a contribution in the field by identifying new types of environment-friendly composites, containing vegetal matters and ecological waste resulting from recycling activities. Outcomes of a series of performed laboratory analyses concerning the thermal conductivity of four different samples of assemblies, are quite promising and candidate these new composites – albeit further analyses are certainly recommended – as a practicable alternative to the mostly used traditional insulating materials.

Education buildings are one of the most important and relevant public buildings. Educational system itself and the conditions of these buildings are very important issues to the community. The sustainability of such buildings can only be achieved to the extent that, at local level, measures regarding the physical renovation will be combined with measures that promote environmental protection. The energy retrofitting of existing school buildings in recent years is part of the policies of the European Union and, consequently, of Romania. In this paper we put together data that establish the current status of a stock of 12 educational buildings and assess the level of applying building standards in each case, the available retrofit solutions, and what would be the impact of the applied solutions. One big challenge regarding existing school buildings is the collection of high-quality data. This paper presents complex data analytics with the aim of providing a framework and a methodology able to identify the best energy retrofit interventions from the perspective of cost-benefit, and to correlate them with the specific characteristics of the educational buildings. Based on the collected and aggregated data, for each building a validating procedure has been put in place by dynamic simulations and a comparison with actual energy use was performed.

Medium voltage gas insulated transmission lines (GIL) are explored with the possibility of a continuous manufacturing process. The cables used SF 6 replacement gases as the dielectric. The alternative to the traditional GIL design makes it feasible for the cables to be suitable for retrofitting within existing cable ducts with high ampacity GIL while addressing the environmental concerns with this technology. RF air-core dielectric cables with equivalent physical dimensions were identified as potential medium voltage GIL designs. Several model cables were fabricated using the RF cables and characterized for electrical insulation designs.