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The concept of smart cities is driven by the need to enhance citizens' quality of life. It is estimated that 70% of the world population will live in urban areas by 2050. The electric grid is the energy backbone of smart city deployments. An electric energy system immune to adverse events, both cyber and physical risks, and able to support the integration of renewable sources will drive a transformational development approach for future smart cities. This article describes how the future electric energy system with 100% electricity supply from renewable energy sources requires the “birth of security and resiliency” incorporated with its ecosystem.

The paper presents a survey for the methods of generating the electric energy from the solar energy , These methods are devided according to the influence of incident light on the different materials into direct and indirect methods. In the first , the solar energy is converted directly to electricity by means of solar cells , without any byproducts and without any moving parts. The indirect conversion of solar energy into electricity is done through intermediate stage , such as thermal , mechanical and chemical . Each of these methods is discussed in details and comparison between them is done regarding the conversion efficiency.

The source of electricity for public facilities at the Green Open Space Park in Balikpapan City, which is used as a tourist spot, is very dependent on PLN sources, resulting in the problem of an electrical energy crisis. The purpose of this activity is to disseminate Smart Bench technology products with the generation of solar cell electricity, which functions as a seat and a place to charge mobile electronic devices as well as a source of electricity for lighting to increase public participation in using parks as tourist areas in the city. The method of implementing this service is applying solar cell technology for the supply of electric energy for park bench facilities, socialization and training to partners regarding the operation of intelligent benches, counselling about mapping the tourism potential of city parks. The result of this activity is the availability of a multifunctional park bench product as a seat, a mobile phone charging station, and a source of lighting for the garden area. In addition, there is an increase in partner knowledge in identifying the potential for park tourism in the city of Balikpapan.

In recent years, triboelectric nanogenerators (TENGs) have developed rapidly and attracted the attention of researchers all over the world. Here, a novel waved-shaped triboelectric nanogenerator using the MgSiO3 powder (W-TENG) was developed. In this work, polyethylene terephthalate film and MgSiO3 powder form the triboelectric pairs. W-TENG devices can convert mechanical energy into electric energy. From the results, the maximum output power of a W-TENG can reach 184 µW. Additionally, a W-TENG can generate an open-circuit voltage (Voc) of 224.26 V, a short-circuit current (Isc) of 2.74 µA, and a transferred charge of 37.8 nC. Moreover, a W-TENG can serve as a self-powered human motion counter. This design describes a portable TENG device that can promote the self-powered human motion sensor application.

District heating and cooling are considered effective solutions to decarbonise the energy use in the building sector. The latest generation of district heating and cooling also increases the potential of integrating heat pumps and chillers in each building substation. The benefits of such integration are the reduction of network temperature and distribution losses; the recovery of waste heat through a bidirectional network; and the decentralised production of heating and cooling. Sizing the network depends mainly on the heat flows between connected buildings. The substation performance and technical installations determine these heat flows. We present in this paper Modelica-based simulations of two design cases for substations. The first design case involves installed heat pump, chiller, and circulation pumps. Alternatively, the second design enables the heat pump to provide direct cooling through a heat exchanger. The models for these installations were developed using the Modelica language to perform continuous-time simulations. The performance in each design case was evaluated in terms of seasonal coefficient of performance and total electric energy use. An analysis on a cluster of 11 buildings suggests that the addition of the direct cooling heat exchanger can save up to 10% of the total annual electric energy use. Additional savings can be achieved by optimising the building supply temperatures and the district network temperature.

The article discusses a mathematical model of a hybrid system that combines photovoltaic and thermoelectric methods for converting concentrated solar energy into electrical energy. The specified mathematical model makes it possible to determine the temperatures of the photovoltaic module, as well as the temperature of the electrodes of the thermoelectric generator module. Optimal operating conditions have been determined for the hybrid system, taking into account the thermal contact resistance at the hot and cold sides of the thermoelectric generator. The simulation proceeded from the fact that only part of the absorbed solar radiation is converted into electricity due to the photoelectric effect, some part is lost due to radiation and convection from the upper surface of the photovoltaic module into the environment, and the rest is transferred to a thermoelectric generator connected to the lower part. photovoltaic module. A thermoelectric generator converts some of the thermal energy it receives from the photovoltaic module into electricity through the Seebeck effect, but most of it goes to the cooling system. The conversion of heat into electrical energy was based on the well-known Seebeck and Peltier effects. Along with these effects, such effects were taken into account as the formation of Joule heat due to the presence of electric current in the thermoelectric generator, Fourier thermal conductivity, as a consequence of the appearance of a temperature gradient in the transitions of a thermoelectric generator and Thomson heat, which arises both due to the presence of a temperature gradient, and electric current. The resulting model of the hybrid system makes it possible to study the effect of changing the temperature difference between the hot and cold electrodes of the thermoelectric generator and the resistance of the external circuit on the performance of the hybrid system. The model also allows the determination of the optimal operating conditions for the hybrid system, taking into account the thermal contact resistance on the hot and cold sides of the thermoelectric generator.

The purpose of this article is to examine the correlations between greenhouse gas (GHG) by CO2eq emissions and the use of electricity on the Praia Vermelha campus of the Universidade Federal Fluminense (UFF) located in Brazil. The study favors understanding and management for the sustainability of the campus operations. The research used electricity consumption data from 2017 to 2019 and quantitative and qualitative data collected in 2020, through online research applied at Praia Vermelha campus. An exploratory and descriptive study, providing familiarity with the problem and deepening knowledge about the phenomenon, seeking a correlation between variables and proposing reflections. We observed a reduction in electricity consumption on the campus in the period surveyed from 2017 to 2019, however, there wasn’t proportional and significant reduction CO2eq emissions in the period between 2018 until 2019. During this period occurred fluctuations in the dispatches of the different power generating plants, considering renewables and fossils sources. We also found that most of survey respondents agree with to implementation of incentive programs and the dissemination of information about GHG emissions on campus to promote the engagement of the academic environment in the efficient use of electricity. We found few peer-reviewed studies dealing with GHG emissions generated in South American universities. Through a bibliographic review, we investigated the commitment of the universities to sustainability and the management of efficient use of electric energy, as well as the methodology for calculating indirect GHG emissions, in CO2eq, related to purchase energy from the System National Interconnected System (SIN) of Brazil.

Smart Grid (SG) systems involves large Information Communication Technology (ICT) infrastructure integrated with the power grid system to allow bidirectional flows of information, for effectiveness and to provide economic and sustainable processes that facilitates constant electricity supplies. As a result of open IoT used in smart grid infrastructure, electricity generation and distribution information are getting more vulnerable to online threats. The need to find effective and mitigating measures to the vulnerability and threats in the systems. As broadband network moves from 4G to 5G networks with its attendant advantages, smart grid interoperability will require a well-structured security strategy to avert cyber-attacks and ensure grid security. Cyber-attack issues are critical factors that need to be understood and mitigating techniques developed to ensure the smooth running of smart grid systems. Research has shown that severe vulnerabilities in the implementation of the smart meter pose a threat to grid infrastructure, as such, it is only when these issues are resolved that we can have a sustainable and realistic smart grid technology. This study addressed these concerns by developing a conceptual model for the mitigation of security vulnerabilities in IoT-based smart grid electric energy distribution systems.

Os serviços de alimentação institucionais devem ga-rantir o fornecimento de uma alimentação segura e de qualidade para os usuários e ao mesmo tempo ser ambientalmente responsável com o uso dos recur-sos naturais. Este estudo teve como objetivo avaliar o desempenho ambiental e as condições higienicos-sanitárias relacionados à produção de refeições em Restaurantes Institucionais (RI) de ensino público em um estado do nordeste brasileiro. A pesquisa caracterizou-se como descritiva exploratória de na-tureza transversal/observacional, realizada em seis restaurantes de instituições de ensino público, sen-do 3 restaurantes universitários e 3 restaurantes de institutos de ensino médio técnico. O desempenho ambiental foi avaliado por meio de um instrumento que abordava o uso de água, energia elétrica, gás, produtos químicos e gestão de resíduos. Para a ava-liação das condições higienicossanitárias nos RI foi utilizada uma lista de verificação contemplando instalações, processos, documentação e registros referente às boas práticas de manipulação dos ali-mentos. Os resultados mostraram que, em relação ao desempenho ambiental, todos os RI alcançaram um escore percentual classificado como bom ou muito bom (60,5 a 86,5%). Gestão de resíduos e uso de energia elétrica obtiveram respectivamente o me-lhor e pior percentual médio de adequação. Em re-lação às condições higienicossanitárias, a média de adequação geral dos IR variou entre 47,3% a 91,7%, sendo o item documentação e registro o que obteve menor adequação em todos os restaurantes. Institutional food services must guarantee the provision of safe and quality food for users and at the same time be environmentally responsible with the use of natural resources. This study aimed to evaluate the environmental performance and the hygienic-sanitary conditions related to the production of meals in Institutional Restaurants (IR) of public education in a state of northeastern Brazil. The research was cha-racterized as exploratory descriptive of a transversal/observational nature, performed in six restaurants of public education institutions, 3 university restaurants and 3 restaurants of technical high school ins-titutes. Environmental performance was assessed using an instrument that addressed the use of water, electricity, gas, chemicals and waste management. For the evaluation of hygienic-sanitary conditions in the IR, a checklist was used, including facilities, processes, documentation and records regarding good food handling practices. The results showed that, in relation to environmental performance, all IR reached a percentage score classified as good or very good (60.5 to 86.5%). Waste management and use of electric energy obtained the best and worst average percentage of adequacy, respectively. In relation to hygienic--sanitary conditions, the average of the general adequacy of the IRs ranged from 47.3% to 91.7%, with the item documentation and registration having the lowest adequacy in all restaurants. Os servicios alimentarios institucionales deben garantizar la provisión de alimentos inocuos y de calidad para los usuarios y al mismo tiempo ser ambientalmente responsables con el uso de los re-cursos naturales. Este estudio tuvo como objetivo evaluar el desempeño ambiental y las condicio-nes higiénico-sanitarias relacionadas con la producción de comidas en Restaurantes Institucionales (RI) de educación pública en un estado del noreste de Brasil. La investigación se caracterizó por ser descriptiva exploratoria de carácter transversal/observacional, realizada en seis restaurantes de ins-tituciones de educación pública, siendo 3 restaurantes universitarios y 3 restaurantes de institutos técnicos. El desempeño ambiental se evaluó mediante un instrumento que abordó el uso del agua, electricidad, gas, químicos y manejo de desechos. Para la evaluación de las condiciones higiénico--sanitarias en el RI, se utilizó una lista de verificación, que incluye instalaciones, procesos, documen-tación y registros sobre buenas prácticas de manipulación de alimentos. Los resultados mostraron que, en relación al desempeño ambiental, todos los RI alcanzaron un puntaje porcentual clasificado como bueno o muy bueno (60,5 hasta 86,5%). La gestión de residuos y el uso de energía eléctrica obtuvieron el mejor y el peor porcentaje medio de adecuación, respectivamente. En cuanto a las condiciones higiénico-sanitarias, el promedio de adecuación general del RI osciló entre el 47,3% y el 91,7%, siendo la documentación y registro del ítem el menos adecuado en todos los restaurantes.

The influence of distortions in voltage and current waveforms on state-of-the-art single-phase and three-phase power meters, commonly used in the utility power system of the Slovak Republic, was studied. A computer-controlled test system capable of generating nonsinusoidal voltages and currents and a reference power quality analyzer were used for this purpose. The results of the experiments on several revenue meters are presented. Some samples exhibited high errors under the tests, while the others operated within their tolerance limit. The overview of the current standards and previously published related studies on the operation of electric energy measuring equipment under determined and random nonsinusoidal conditions is given. The discussion including possible explanations of the phenomenon supervised under the conducted tests is provided.

At this time, almost all Public Street Lights (PJU) still use the type of mercury and SON-T lamps, even though the mercury and SON-T lamps absorb a considerable amount of electricity. Public street lighting is usually on almost all nights, and this is a waste of electricity. Public street lighting is usually on most nights and thus is a waste of electricity. Usually, when it is past midnight, the streets are quiet, so the street lighting should be reduced in intensity to save electricity. Based on this problem, this research uses an experimental method (Experiment) to create a design to make efforts in saving electricity. The method used includes electrical and systematic design. The steps taken include the stage of literature research, designing, manufacturing hardware and software, integrating the system, and testing and analyzing the system. Considering these theories, we can know the programming of the microcontroller ATMega 328, Photocell Sensor, PIR Sensor, LED Lights, and Power Supply. This research using several tests, including testing Photocell Sensor, PIR Sensors, LDR Sensors, and LED Lights. Photocell sensor to detect conditions day or night. PIR sensor functions to detect movement, LDR sensor to detect movement, LED lights are used to increase and decrease light intensity. For all the tests above, the results obtained when the PIR and LDR sensors have not detected any movement will dim the intensity of the LED lights. After the PIR and LDR sensors have detected the movement of the LED lights, they will turn automatically bright.

The electric power sector is considered as the most important active economic sector in public life aspects including industrial, agricultural, service and recreational ones. It is known that traditional energy (fossil fuels) causes climate problems. Such problems have negative impact on the atmosphere, due to the increase in air pollution and the emergence of global sources such as solar energy as it is clean and renewable energy. As the southern Badia of Iraq has a high solar energy, it is possible to invest it in the production of electric energy and then employing it in the developmental fields in those cities (mentioned above) and even remote ones. Thus, this will lead to reducing the quantities of fossil energy consumption as well as reducing its polluting emissions to the atmosphere and its negative effects on nature, man in particular. The main objective of this study is to discover the potentials of the study area of solar radiation energy evaluating and choosing the optimal sites for the construction of the aforementioned power stations. In processing its data, the study used statistical methods to calculate the amount of solar energy reaching the surface of the study cities in the southern Badia of Iraq according to the following equation: Solar Energy = the amount of solar energy (Kilo Watt/ M2/ day) = the total solar radiation (calorie/C2/day) *constant, where the constant equals (0.0116) The study reached the most important results: Some of the study stations recorded the best optimal sites for constructing solar power stations. These are the stations of As Safawi, Busayyah, As-Salman, Al-Ma'aniya, Al-Shabajah, Al-Samawah, Najaf, Al-Nukhayb, and Al-Rutba. On the other hand, the Basra and Zubair stations recorded the lowest values for solar energy; therefore they are not ideal sites compared to other stati.

The purpose of this study is to determine the effect of the presence of a fan in the wood drying room in the drying time of wood. In addition, it is also to determine the performance of the steam compression cycle engine used in wood drying machines and the conditions of air entering and leaving the wood drying room. Wood drying machines work on a source of electrical energy. The research was conducted experimentally. Variations in the study were carried out on the presence of fans in the drying room: (a) there were no fans and (b) there were 2 fans. The dried object is a sengon wood board, which has a length of 2 m, a width of 20 cm, and a thickness of 2 cm. The number of wooden planks is 70 wooden planks of uniform size. The wooden planks before drying have a moisture content of 29.6%, and when dry, have a moisture content of 10%. The research gave the following results: (a) if there are 2 fans in the drying room, the time needed to dry the sengon wood planks is around 42.6 hours, whereas if there is no fan around 49.9 hours (b) the average Coefficient of Performance (COP) of the steam compression cycle engine is 10.65 (c) The air condition enters the drying room when there are 2 fans, has a dry ball air temperature of 40oC with a relative humidity of 32% RH and the air condition when it comes out, has a dry ball air temperature of 28oC with a relative humidity of 73% RH.

The increase of energy consumption of fossil fuel as a result of the increase in the population of Iraq, the development of urban lifestyle, the increase in the number of vehicles as well as the increase of power generators has led to dangerous environmental risks, air, water and soil pollution, the spread of cancers and sensitivity diseases besides the reduction of the Iraqi exports of raw oil as a result of domestic consumption. Therefore; searching for solutions to restricting or surmounting these effects such as finding clean renewable sources of power have become inevitable. Among those renewable sources which are environmentally friendly and of middle cost is the solar power that includes solar heater and solar cells boards. Using 100.000 solar heaters saves (324.800 Megawatt hour) within one year, while using 100.000 solar cells system with an energy of (1000 watt) saves (438.000 Megawatt hour) within one year. Other means of reducing the effects of using fossil fuel is spreading the culture of power rationing and avoiding the waste and excessive consumption through cooperation with educational institutions by setting special programs such as courses, symposiums, posters and setting out a day for power consumption rationing. Turning off 10% of sets operation time in 1.000.000 house would save more than (2.076.120 megawatt hour) per annum.

Power is essential in nonferrous arc furnace plants for burning and melting scraps, as well as for the composition of raw materials to produce the furnace product. To ensure high-quality operation, the electric energy is controlled by changing the tap positions. However, there is no standard working pattern to determine the most effective option for changing the tap positions to obtain optimal power and product quantity. This study proposes a method to analyze and determine the working patterns in nonferrous arc furnace plants by adopting dynamic programming. To find the best objective value candidates, statistical methods were utilized to obtain the optimal values of the total elemental power and total product quantity. Moreover, if the maximum product quantity minimum electric consumption are known, the least power per product quantity (PPQ) can be easily obtained. Thus, it is reasonable to analyze the sequences of tap positions and then obtain the best PPQ using an approach of solving a recurrence problem with the widely used dynamic programming approach. We demonstrated that the proposed method suggested the working pattern of tap positions, thereby providing relatively good PPQs in comparison with the conventional method.

Implementing Photovoltaic Systems (SFV) Interconnected to the electrical network reduces the energy rate where the charge is solely for consumption. Analyzing Great Demand rate in Medium Hourly Voltage (GDMTH) allows SFV interconnected to the network helping to reduce the maximum demand for peak hours increasing the impact of the generation of energy through the PV system at rates where hourly consumption is considered. It is identified that the highest demand for energy is in the intermediate hours and lower consumption in peak hours; however, reviewing the electricity bill, the charge for consumption during peak hours increases significantly, this is why, SFV is proposed to reduce demand during peak hours. Subsequently, the implementation of a prototype to generate, store, and manage the injection of energy during peak hours is presented to reduce the cost of energy in this hour time up to 37% of monthly electricity bill. Resumen Implementando Sistemas Fotovoltaicos (SFV) Interconectados a la red eléctrica se reduce la tarifa donde ésta es únicamente por el consumo de energía. Analizando la tarifa Gran Demanda en Media Tensión Horaria (GDMTH) permite que SFV interconectados a la red ayuden a reducir la demanda máxima en horario punta aumentando el impacto de la generación de energía por medio de sistema FV en tarifas donde se considera el consumo horario. Se identifica que la mayor demanda de energía es en el horario intermedio y menor consumo en horario punta; sin embargo, revisando la factura, el cargo por consumo en horario punta aumenta significativamente, por tal razón, se propone un SFV para abatir el consumo en este horario. Posteriormente se presenta la implementación de un prototipo para generar, almacenar y gestionar la inyección de energía en horario punta para reducir el costo de energía hasta un 37% en la factura mensual.

Various classes of chemical compounds that are considered promising thermoelectric materials with a high efficiency of converting thermal energy into electric energy are studied. The strategies for increasing the thermoelectric figure of merit and examples of their application are described. The progress in studies of compounds, such as SnX (X = S, Se, Te), AgSbTe2, M3 – xTe4 (M = La, Nd, Pr), Mg3Sb2, Mg2X (X = Si, Ge, Sn), and MgAgSb, is evaluated. The contribution of the use of information technology to the development of thermoelectric materials science is determined.