Academic literature on the topic 'Consumption of thermal and electric energy'

A promising direction in the development of drying plants in the technologies of processing fruit and berry raw materials is the use of aerodynamic heating dryers. They implement the principle of transformation of electrical energy consumed to drive a centrifugal fan into thermal energy due to mutual friction of air flows circulating in a closed chamber. In this case, the overwhelming part of the electrical energy supplied to the rotor is spent on overcoming aerodynamic losses in the flow path of the impeller and in the drying chamber. To reduce the energy consumption of the drying process by reducing the energy consumption for heating the drying agent in the drying chamber, it is proposed to utilize the heat of the spent drying agent by equipping the dryer with a combined heat exchanger. It combines a plate heat exchanger and a solar air collector. The aim of the study was to analyze the efficiency of using a combined heat exchanger to reduce the energy consumption of an aerodynamic dryer when drying apples. The operation of the drying plant was investigated with and without a combined heat exchanger. To record the parameters of the drying agent, the environment, and the consumption of electric energy, an eight-channel TRM-138 thermoregulator meter with thermal resistance sensors and an electric energy meter with current transformers were used. An eight-channel TRM-138 thermoregulator meter with thermal resistance sensors and an electric en-ergy meter with current transformers was used to record the parameters of the drying agent, the en-vironment, and the consumption of electric energy. The research results showed that the use of a combined heat exchanger made it possible to increase the temperature of the drying agent entering the drying chamber by an average of 20 ºС relative to the ambient air temperature. A more intensive increase in the temperature of the drying agent when using a combined heat exchanger made it pos-sible to reduce the drying time by 3 hours. At the same time, electricity consumption decreased by 27.4%.

The present work examines average relative capital investment and fuel consumption for electric and thermal energy supply of the combined-cycle plants having 30–125 MW gas turbines commissioned at Russian thermal power plants in 2015–2020. In this work, we used general calculation methods of average relative capital investments and fuel consumption for the electrical and thermal energy supply using power equipment of thermal power plants. To assess the scope of commissioning gas turbines incorporated into the combined-cycle plants, they were classified into three groups by electrical power: 30–59 MW, 60–99 MW and 100–125 MW. The scope of commissioning gas turbines incorporated into the Russian combined-cycle plants in 2015–2020 was analysed. The average relative capital invest-ment in combined-cycle plants having 30–125 MW gas turbines, as well as the average specific fuel consumption for the electrical and thermal energy supply, were calculated. The calculations were carried out for each part of combined-cycle plants integrated into thermal power plants with a breakdown by seven Unified Energy Systems of Russia. The quantita-tive commissioning of gas turbines is compared for the periods from 2010 to the economic crisis of 2014 and after 2014 to the present: a ~2.5-fold decrease is demonstrated. A preliminary evaluation of the increase in average relative capital investment in combined-cycle plants having gas turbines of the same electric power was performed.

Electrical energy is the highest energetic cost in recirculation aquaponic systems (RASs), especially for fish-tank water. Therefore, reducing energy consumption is one of the challenges in developing RAS models. In this study, eleven experimental setups, based on numerical models from an earlier investigator, were built to investigate. Among them, three additional cases (cases 9–11) investigated the transient discharging energy efficiency of thermal energy storage (TES). Cases 9–11 considered three temperature levels, namely, 65–75 °C, 71–81 °C, and 81–87 °C, with a mass flow rate of 0.166 kg/s. The results show that when heating 3.4 m3 of fish tank water from 24.5 °C to 28 °C, the average temperature error of the tank water was between 1.2% and 3.4%. The difference in the heat transfer rate was within ±4.2%. The error in the thermal efficiency was below 8.0%. The error range of the total required thermal energy was from 6.4% to 11.5%. Cases 9–11 used 5.6%, 6.4%, and 7.2% of the thermal energy of the TES tank, respectively. The electrical energy consumption was low compared to the thermal energy of the fish tank water received from the TES unit. Therefore, the proposed low-energy-consumption heating method can replace electric heaters.

Abstract New energy vehicles play a bigger role under the National VI emission standard and the double-point policy conditions, which is the focus of Original Equipment Manufacturers (OEMs) and consumers due to the advantages of low fuel consumption and long battery life. The front cabin of a hybrid electric vehicle (PHEV) includes the cooling system of the engine, electric motors, controller and condenser, etc. Compared with fuel and pure electric vehicles, the front cabin has a higher heat load, smaller space, and a great influence of the radiators for PHEV, which has more requirements for the cooling module. As people’s requirements for power and comfort continue to increase, the cost and energy consumption of thermal management systems are also rising. Hence, all OEMs have shifted their focus to developing a new generation of thermal management systems. The performance of the new-generation hybrid vehicle thermal management system can meet the performance requirements of the entire vehicle, and it has the advantages of being suitable for platformization, reducing costs, comprehensive utilization of vehicle energy to reduce energy consumption, high radiating efficiency, small front-end module size, and low fan power.

A characteristic feature of the present day development of power engineering lies in the increase in the unevenness of power systems schedules. The structure of generating powers of Ukrainian energy engineering is overloaded with basic powers and characterized by a sharp deficit of maneuvering wanes. To cover the uneven load of the power system during the operation of existing and construction of new power plants, it is necessary to take into account the possibility of their operation under maneuvering modes. This paper determines the influence of work of power plants i under maneuvering modes on the specific consumption of conditional fuel on the released electric energy at working on gas or coal fuel. Fuel consumption for starting of a unit depends on its type and downtime in reserve. The use of steam–and–gas facilities and gas turbines helps to enhance the maneuverability of power plants. Alternative options for the development of thermal energy are the introduction of gas–piston power plants and power units with fluidized–bed boilers. We present formulas for the calculations of fuel consumption on by power units for start–ups and specific consumptions depending on the load and degree of their involvement to regulating loads for different thermal energy technologies: steam–turbine condensation and district heating power units; steam–and–gas and gas turbine plants; gas piston installations; power units with fluidized bed boilers. For enhancing the maneuverability of power plants, working on fossil fuels, their modernization and renewal of software are necessary. Quantitative assessment of the efficiency of power units and separate power plants during their operation under variable modes is important for forecasting the structure of generating capacities of power systems, the need to introduce peak and semi–peak capacities, the choice of the most profitable composition of operating equipment at different schedules of electrical loads Keywords: thermal power, power unit, maneuverable mode, electrical load, specific fuel consumption

In battery electric buses (e-buses), the substantial energy consumption of the heating, ventilation, and air conditioning (HVAC) system can cause significant reductions of the available travel range. Additionally, HVAC systems are often operated at higher levels than what required for the thermal comfort of the passengers. Therefore, this paper proposes a method to experimentally investigate the influence of the HVAC system on the energy consumption and thermal comfort in a 12m e-bus. An appropriate thermal comfort model is identified and the required climatic input parameters are selected and measured with self-developed sensor stations. The energy consumption of the e-bus, the state of charge (SoC) of the battery and the available travel range are measured by an embedded data logger. Climatic measurements are then performed with heating on and off on a Berlin bus line in winter conditions. The results show that the energy consumption of the e-bus is increased by a factor of 1.9 with heating on, while both the SoC and travel range are reduced accordingly. Comparing the thermal comfort with heating on and off, a decrease from “comfortable” to “slightly uncomfortable but acceptable” is observed.

In Kuwait, where the government subsidizes approximately 95% of residential electricity bills, most of the country’s energy consumption is for residential use. In particular, air-conditioning (AC) systems for cooling, which are used throughout the year, are responsible for residential electric energy consumption. This study aimed to reduce the amount of energy consumed for cooling purposes by developing a thermal comfort-based controller. Our study commenced by using a simulation model to investigate the possibility of energy reduction when using the predicted mean vote (PMV) for optimal control. The result showed that control optimization would enable the cooling energy consumption to be reduced by 33.5%. The influence of six variables on cooling energy consumption was then analyzed to develop a thermal comfort-based controller. The analysis results showed that the indoor air temperature was the most influential factor, followed by the mean radiant temperature, the metabolic rate, and indoor air velocity. The thermal comfort-based controller-version 1 (TCC-V1) was developed based on the analysis results and experimentally evaluated to determine the extent to which the use of the controller would affect the energy consumed for cooling. The experiments showed that the implementation of TCC-V1 control made it possible to reduce the electric energy consumption by 39.5% on a summer representative day. The results of this study indicate that it is possible to improve indoor thermal comfort while saving energy by using the thermal comfort-based controller in residential buildings in Kuwait.

The primary objective of a hybrid electric vehicle (HEV) is to optimize the energy consumption of the automotive powertrain. This optimization has to be applied while respecting the operating conditions of the battery. Otherwise, there is a risk of compromising the battery life and thermal runaway that may result from excessive power transfer across the battery. Such considerations are critical if factoring in the low battery capacity and the passive battery cooling technology that is commonly associated with HEVs. The literature has proposed many solutions to HEV energy optimization. However, only a few of the solutions have addressed this optimization in the presence of thermal constraints. In this paper, a strategy for energy optimization in the presence of thermal constraints is developed for P2 HEVs based on battery sizing and the application of model predictive control (MPC) strategy. To analyse this approach, an electro-thermal battery pack model is integrated with an off-axis P2 HEV powertrain. The battery pack is properly sized to prevent thermal runaway while improving the energy consumption. The power splitting, thermal enhancement and energy optimization of the complex and nonlinear system are handled in this work with an adaptive MPC operated within a moving finite prediction horizon. The simulation results of the HEV SUV demonstrate that, by applying thermal constraints, energy consumption for a 0.9 kWh battery capacity can be reduced by 11.3% relative to the conventional vehicle. This corresponds to about a 1.5% energy increase when there is no thermal constraint. However, by increasing the battery capacity to 1.5 kWh (14s10p), it is possible to reduce the energy consumption by 15.7%. Additional benefits associated with the predictive capability of MPC are reported in terms of energy minimization and thermal improvement.

The self-consumption without surplus to the grid is one of the aspects of the new Spanish law for prosumers. Increasing the share of renewable energy sources into the grid inherently leads to several constraints. The mismatch between the energy demand and the renewable energy production, which is intermittent in nature, is one of those challenges. Storage offers the possibility to decouple demand and supply, and therefore, it adds flexibility to the electric system. This research evaluates expanding electricity self-consumption without surplus to the grid by harnessing thermal mass storage in the residential sector. The methodology is investigated by using a variable refrigerant flow air conditioner system. Because there is no option to export the excess capacity to the grid, this research proposes an approach to profiting from this surplus energy by activating structural thermal mass, which is quantified from the information acquired using a building energy model. For this purpose, an EnergyPlus model of a flat in Pamplona (Spain) was used. The optimization analysis was based on a set-point modulation control strategy. Results show that under adequate climatological circumstances, the proposed methodology can reduce the total electric energy from the grid between by 60– 80 % .

Nowadays the aviation industry is playing an important role in our daily life, since is the main medium that satisfies the present human needs to reach long distances in the fastest way. But such benefit doesn’t come free of collateral consequences. It is estimated that each year, only the air transport industry produces 628 mega tonnes of CO2. Therefore, urgently actions need to be implemented considering that the current commercial fleet will be doubled by 2050. The research field for more efficient aircraft systems is a very constructive field; where novel ideas can be exploited towards the mitigation of the coming air transport development. In this research the configuration of the Environmental Control System (ECS) has been analysed aiming to reduce its energy consumption for both, fixed-wing and rotary-wing aircraft. This goal is expected to be achieved mainly through the replacement of the main source of power that supplies the ECS, from pneumatic to electric. Differently from the conventional ECS, a new electric-source technology is integrated in the system configuration to compare its effects on the energy consumption. This new technology doesn’t bleed air directly from the engines; instead of that, it takes the air directly from the atmosphere through the implementation of an electric compressor. This new technology has been implemented by Boeing in one of its most recent airplanes, the B787. Towards achieving the main goal, a framework integrated with five steps has been designed. An algorithmic analysis is integrated on the framework. The first step meets the required aircraft characteristics for the analysis. The second step is in charge of meeting the mission profile characteristics where the overall analysis will be carried out. The third step assesses the conventional ECS penalties. The fourth step carries out a complex analysis for the proposed electric ECS model, from its design up to its penalties assessment. The fifth step compares the analysis results for both, the conventional and the electric models. The fourth step of the framework, which analyses the electric ECS, is considered the most critic one; therefore is divided in three main tasks. Firstly, a small parametric study is done to select an optimum configuration. This task is carried out towards meeting the ECS air conditioning requirements of a selected aircraft. Secondly, the cabin temperature and pressurization are simulated to analyse the response of the configured electric ECS for a mission profile. And finally, the fuel penalties are assessed in terms of system weight, drag and fuel due power-off take. To achieve the framework results, a model which receives the name ELENA has been created using the tool Simulink®. This model contains 5 interconnected modules; each one reads a series of inputs to perform calculations and exchange information with other modules.

Orientadores: Gilberto De Martino Jannuzzi, Elizabeth Ferreira Cartaxo
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
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Resumo: Esta dissertação tem como objetivo avaliar os impactos da redução do consumo de energia elétrica em Manaus através de medidas de eficiência energética em climatização residencial. A escolha da correta orientação geográfica, a pintura das paredes e dos telhados com cores claras, a inclusão de isolamento térmico EPS (Isopor) no forro, a inclusão de isolamento reflexivo por baixo do telhado e a abertura de áticos, foram medidas de eficiência energética aplicadas na residência do estudo de caso para avaliar a redução das cargas térmicas dos seus respectivos recintos internos (quartos). Outra medida de eficiência energética utilizada foi a substituição de condicionadores de ar do tipo janela de baixa eficiência por equipamentos de alta eficiência. As estimativas das cargas térmicas resultantes das aplicações das medidas de eficiência energética foram obtidas por meio da utilização do software CARRIER E20-II, HAP, v4.33., cuja licença de uso é encontrada à venda no mercado nacional. Definidas as cargas térmicas dos quartos, foram especificados os condicionadores de ar do tipo janela que seriam usados na climatização desses ambientes. O emprego combinado dessas medidas de eficiência energética permitiu que fossem quantificadas as respectivas economias de consumos e de redução de demanda de energia elétrica e seus efetivos impactos sobre o Sistema Manaus.
Abstract: This thesis aims to assess the impacts of electricity consumption reduction in Manaus through energy efficiency measures applied in home climatization. The choice of correct geographical orientation, walls and roofs painting with clear colors, the inclusion of thermal insulation EPS (Styrofoam) in the lining, the inclusion of reflective insulation under the roof, attic opening and closing, are energy efficiency measures applied in the case study residence to reduce the thermal loads on their respectives rooms. Another efficiency measure used was the replacement of low efficiency window air-conditioners for high-efficiency ones. The resulting thermal loads from the application of these measures were obtained through the use of software CARRIER E20-II, HAP, v4.33., whose using license is found for sale on the domestic market. Defined the rooms thermal loads, the cooling capacities of the window air-conditioners were specified to be used in the cooling of these environments. The combined employment of these energy efficiency measures has allowed quantify their electric energy consumption economies and demand reductions and its impacts on the Manaus System.
Mestrado
Planejamento de Sistemas Energeticos
Mestre em Planejamento de Sistemas Energéticos

Магістерська дисертація «Підвищення енергоефективності дитячого садочку та моделювання енергоспоживання з використанням сучасного програмного забезпечення» складається з 99 сторінок, 28 рисунків, 49 таблиць, а також містить 42 джерел в переліку посилань. Актуальність теми полягає у використанні сучасних методів моніторингу споживання енергоресурсів для прийняття найбільш ефективних управлінських рішень з точки зору енергоефективності. Метою роботи є дослідження енергоспоживання будівлі на прикладі дитячого садка та впровадження заходів з енергозбереження. Завдання дослідження – провести енергоаудит дитячого садку, розрахувати навантаження на систему опалення та електропостачання, визначити шляхи підвищення енергоефективності будівлі та провести розрахунок доцільності проведення заходів з енергозбереження, розробити систему автоматизованого обліку енергоносіїв. Об'єкт дослідження – дитячий садочок у м. Києві серійних часів забудови. В ході роботи виконано детальне енергетичне обстеження, що включало: - збір вихідних даних щодо характеристик будівлі, її огороджувальних конструкцій та внутрішньобудинкових інженерних систем; - збір даних щодо енергоспоживання об’єкту; - вивчення режимів експлуатації; - уточнення геометричних характеристик будівлі; - розрахунки теплотехнічних показників огороджень, - дослідження умов мікроклімату будівель, - виконання необхідних інструментальних вимірювань і розрахунків; - визначення питомих енергетичних характеристик; - розробка економічно обґрунтованих заходів з енергозберження з доведенням характеристик огороджень до нормативних вимог; - моделювання енергоспоживання будівлі в спеціалізованому програмному продукті з визначенням енергетичних характеристик; - розробка пропозицій щодо розвитку системи енергетичного менеджменту. Предмет дослідження – аналіз доцільності проведення заходів з енергозбереження в сферах тепло- та електропостачання в дитячому садку в місті Київ з використанням сучасного програмного забезпечення. Наукова новизна магістерської дисертації полягає у розробці системи автоматизованого обліку енергоносіїв у дитячому садку. Отримані результати, запропоновані методики та підходи можуть використовуватись для аналізу енергоспоживання інших будівель.
The master's dissertation "Improving the energy efficiency of kindergarten and modeling energy consumption using modern software" consists of 99 pages, 28 figures, 49 tables, and also contains 42 sources in the list of references. The relevance of the topic is to use modern methods of monitoring the consumption of energy resources to make the most effective management decisions in terms of energy efficiency. The purpose of the work is to study the energy consumption of the building on the example of a kindergarten and the implementation of energy saving measures. The task of the research is to conduct an energy audit of the kindergarten, calculate the load on the heating and electricity supply system, determine ways to increase the energy efficiency of the building and calculate the feasibility of energy saving measures, develop an automated energy metering system. The object of research is a kindergarten in Kyiv of serial times of construction. In the course of the work a detailed energy audit was performed, which included: - collection of initial data on the characteristics of the building, its enclosing structures and indoor engineering systems; - collection of data on energy consumption of the facility; - study of operating modes; - specification of geometrical characteristics of the building; - calculations of thermal indicators of protections, - study of the microclimate of buildings, - performance of necessary instrumental measurements and calculations; - determination of specific energy characteristics; - development of economically justified measures for energy saving with bringing the characteristics of fences to regulatory requirements; - modeling of energy consumption of the building in a specialized software product with the definition of energy characteristics; - development of proposals for the development of the energy management system. The subject of the research is the analysis of the expediency of carrying out energy saving measures in the spheres of heat and electricity supply in a kindergarten in the city of Kyiv with the use of modern software. The scientific novelty of the master's dissertation is to develop a system of automated energy accounting in kindergarten. The obtained results, proposed methods and approaches can be used to analyze the energy consumption of other buildings.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
Esta dissertação desenvolveu-se de forma articulada com o projeto de PeD LIGH-ANEEL, coordenado pelo Programa de Pós-Graduação em Metrologia (PósMQI), Projeto Ref. PeD 003/2008, intitulado Racionalização do uso de energia e aplicação da termoacumulação como estratégia para proposição de tarifa diferenciada voltada a clientes comerciais de alto consumo. A dissertação teve como objetivo o desenvolvimento e validação de um algoritmo para identificação de clientes potenciais ao uso da tecnologia de termoacumulação. O trabalho orientou-se no contexto da crescente demanda por energia imposta ao setor elétrico pela expansão da economia, notadamente em horários de alta demanda. A motivação deste trabalho, atendendo aos interesses do PósMQI na área de energia, é oferecer uma ferramenta de auxílio à decisão para o planejamento energético das concessionárias. Como resultado obteve-se o mapeamento das curvas de cargas, obtidas por meio do sistema computacional desenvolvido (SIMCAR). Este sistema (amigável) permite enquadrar os clientes potenciais, segundo características de consumo estruturadas em três categorias indicativas do uso da termoacumulação: muito potencial, potencial e já modula. Dentre as conclusões, o algoritmo desenvolvido mostrou-se ferramenta eficaz de auxílio ao planejamento energético e a termoacumulação uma alternativa sustentável para adequação da matriz energética do país, podendo gerar economias de até 40 porcento.
An algorithm to measure and detect potential thermo-accumulation customers among the clients of a distributing utility was proposed in this work. Such algorithm uses statistical methods for the treatment of missing data and is applied to the measured hourly demands of medium and high voltage customers of the utility. Basically, the thermo-accumulation technique can be defined as a strategy to shift load from peak hours to off-peak hours. The algorithm allows the construction of load curves from the observed load series after the removal of outliers and/or missing values. From the profile of such curves, the algorithm produces the classification of the clients into three possible categories: higly potential, just potential and non potential (i.e. an already modulated client). Also important to mention this dissertation, is part of an R&D project developed for a brazilian southern utility. A friendly computer system named SIMCAR, developed in Visual Basic, implemented the proposed algorithm. As a final word, in surveys conducted with users of this technology, it was mentioned that the savings on energy consumption can be as high as 40 per cent.

A busca de melhoria de produtos siderúrgicos leva uma atenção especial para a área de aciarias. A introdução da metalurgia da panela, e portanto no refino secundário, contribuiu fundamentalmente para o aumento da qualidade do aço produzido. Um dos efeitos foi o aumento do tempo de residência do aço na panela, o que obrigou a utilização de materiais refratários de melhor qualidade. O controle da temperatura do aço líquido ao longo do processo de produção é de fundamental importância para se atingir os requisitos de qualidade e produtividade exigidos atualmente. Com o desenvolvimento de tecnologias siderúrgicas e a busca pela eficiência energética, torna-se necessário o conhecimento e redução das perdas térmicas do aço durante todo o ciclo produtivo. Neste trabalho foram estudadas, em uma aciaria elétrica a arco, as correlações entre as perdas térmicas das panelas através do conhecimento dos tempos de espera e do tempo de transporte das panelas do forno elétrico a arco até o forno-panela, além de comparar a temperatura do revestimento refratário de panelas com e sem isolante refratário. Melhorias no ciclo de panelas foram propostas visando diminuir as perdas térmicas das panelas, otimizar o ciclo de panelas e, consequentemente, reduzir o consumo de energia elétrica do forno-panela, diminuindo os custos envolvidos durante o processo de fabricação do aço. Os resultados apresentaram significância estatística entre o consumo de energia elétrica do fornopanela e as perdas térmicas das panelas. Através dos resultados obtidos observou-se que a minimização do tempo de espera da panela antes de iniciar o vazamento e a diminuição do tempo de transporte da panela até o forno-panela são fundamentais para diminuir as perdas térmicas nas panelas.
The search for improved steel products takes special attention to the melthops. The introduction of ladle metallurgy, and therefore the secondary refining, contributed essentially to increase the quality of steel produced. One effect was to increase the residence time of the steel in the ladle, forcing the use of refractory materials of better quality. Temperature control of liquid steel during the process is of fundamental importance for achieving the requirements of quality and productivity currently required. With the development of technologies and the reach of energetic efficiency, it becomes necessary to reduce the thermal losses during the steel production cycle. In this study the correlations between the thermal losses in the ladles through the knowledge of waiting times and transport times of the ladles to the of the electric arc furnace to the ladle furnace were determined as well as a comparison between temperatures of ladle refractory lining with and without refractory insulation. Improvements in the ladle cycle were proposed to reduce the thermal losses in the ladles and to optimize the ladle cycle and, consequently, to reduce the electric energy in the ladle furnace, reducing the costs involved during the manufacturing process of steel. The results showed statistical significance between the energy consumption in the ladle furnace and heat losses in the ladles. The results obtained showed that minimizing the waiting time of the ladle before the tap and reducing transportation time of the ladle to the ladle furnace are essential to reduce the heat losses in the ladles.

Orientador: Luiz Antonio Rossi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: A importância da suinocultura brasileira no contexto socioeconômico do país é cada vez mais evidente. Por ser uma atividade que gera milhares de empregos anualmente, além de incrementar o produto interno bruto da nação por meio das expressivas exportações da carne suína, cada vez mais atenção é despendida com os requerimentos dos animais. Apesar disso, pouco tem sido pesquisado sobre as exigências de uma categoria em especial, a dos machos reprodutores do plantel, que são extremamente susceptíveis a condições climáticas adversas. Deste modo, torna-se importante a realização de estudos acerca dos requisitos necessários para mantê-los em conforto térmico, visto que são grandes as perdas na produção devido aos dias muito quentes e às grandes amplitudes térmicas. Uma alternativa para minimizar estas perdas é o uso de sistemas de climatização. Este trabalho teve por objetivo avaliar dois grupos de cachaços, grupos A e B, alojados, respectivamente, em instalações climatizadas por meio de sistema automatizado de ventilação artificial e nebulização, e em instalações climatizadas apenas por ventilação artificial e seguindo o manejo de acionamento dos ventiladores já praticado na propriedade. Foram considerados aspectos de desempenho reprodutivo e conforto térmico dos animais e do uso de energia elétrica pelos equipamentos de climatização. O experimento foi conduzido em uma granja comercial localizada na cidade de Capivari/São Paulo, com animais de uma mesma linhagem genética. O parâmetro utilizado na comparação do desempenho reprodutivo dos animais de ambos os grupos foi a análise das características do sêmen, que se relacionam diretamente com a taxa de prenhez das fêmeas. As edificações de alojamento dos animais também foram comparadas, avaliando-se variáveis climáticas, custos operacionais, gastos com equipamentos de climatização e automação, além da utilização da energia elétrica por parte dos mesmos. Os principais resultados obtidos demonstraram que o sistema de climatização automatizado manteve os animais em uma condição ambiental mais segura, porém não houve melhora nos índices de qualidade seminal dos animais deste grupo. Os valores médios de volume seminal e concentração espermática foram superiores nos animais do grupo B. Os impactos no custo mensal da conta de energia elétrica do posto transformador que fornece energia elétrica para a instalação dos cachaços foram de 2,26% e de 4,82%, para os dois meses completos avaliados
Abstract: Swine grow activities in Brazil is exhibiting an increasing importance to the national social economy. The particular attention devoted to the animal physical requirements is strongly supported by the direct and indirect job opportunities generated as well as by the significant swine meet exportation which push the national internal gross product to high levels. In spite of that, little research efforts has been directed to a special animal group identified as the breeding stock reproducing males, which are very susceptible to temperature changes. That information gives support to a deep study on animal thermal comfort, which is strongly associated to production losses and to the thermal amplitude variations. The application of environmental controlling systems aims to minimize these above referred losses. This research work aimed to evaluate two groups of males, named group A and group B, kept under artificial automatic ventilation and nebulization, as well as only under artificial ventilation following the traditional fan operation, respectively. Factors as reproducing performance, animal thermal comfort, as well as electrical energy use by the environment controlling system have been considered. Experimental trials were carried in a swine growing facility located at Capivari, SP, Brazil by employing animals belonging to a same commercial genetic group. Semen characteristics were employed as a factor of comparison, which are associated to the female pregnancy rate. The shelter¿s building of those animals were also compared, by assessing up climatic variables, operating costs, spending on air conditioning equipment and automation, and the use of electric energy by them. The main results showed that the automated system of air conditioning kept the animals in a safer environmental condition, however there was no improvement in seminal quality scores for the animals of this group. The mean values of seminal volume and sperm concentration were higher in the animals of group B. The impacts on the cost of monthly account of electric energy of the post processor, which provides electricity for the installation of males, were 2.26% and 4.82% for the two whole months assessed.
Mestrado
Construções Rurais e Ambiencia
Mestre em Engenharia Agrícola

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FINEP - Financiadora de Estudos e Projetos
A contribuição das fontes de energias alternativas, principalmente a solar térmica, para a diversificação da matriz energética brasileira é importante devido, principalmente, ao aumento da demanda do consumo de energia elétrica, ocasionado pelo progresso e desenvolvimento da população e do País. Parte deste aumento é consequência do uso simultâneo de milhares de chuveiros elétricos, na maioria das vezes no horário de ponta, considerado um dos responsáveis pelo elevado pico na curva de demanda entre 18 e 21 horas. Frente a isso, a utilização da energia solar através de sistemas de aquecimento solar para o uso doméstico, vem ao encontro deste propósito. Após análise do consumo médio mensal de energia elétrica fornecida pela concessionária AES Sul no período de um ano em um conjunto residencial na cidade de Canoas – RS, foi possível estimar o custo da utilização do chuveiro elétrico nesse local, por domicílio, que representa entre 25 a 30 % da fatura de energia elétrica. A produção de energia térmica através de sistemas de aquecimento solar para pré- aquecimento de água quente para uso doméstico foi simulada utilizando-se o software TRNSYS, para diversas configurações de sistemas (área de coletor e capacidade de armazenamento). A relação entre a demanda de energia para aquecimento de água e a energia produzida pelo SAS foi parametrizada utilizando-se o conceito de fração solar mensal e anual. Foi considerada uma temperatura mínima de consumo de água quente de 40 °C e um perfil de consumo correspondente à taxa de ocupação média dos domicílios no local. Os dados climáticos necessários para a simulação foram obtidos a partir do ano meteorológico típico (TMY) para Porto Alegre. Os resultados obtidos das diversas simulações mostraram que é possível obter uma economia direta para consumidor de até 58% de energia consumida pelo chuveiro elétrico e uma economia de energia estimada em 12.399 kWh para o sistema elétrico ao longo de 20 anos. Estes resultados podem ser melhorados com a diminuição do custo unitário do SAS ou através de incentivos decorrentes da diminuição dos custos de ampliação da capacidade da rede elétrica por parte das concessionárias, decorrentes da mudança do perfil de carga do sistema.
The contribution of alternative energy sources, particularly solar thermal, to diversify the Brazilian energy matrix is important, mainly due to increased demand of electricity consumption, caused by the progress and development of the population as well as the country. Part of this increase is a consequence of the simultaneous use of thousands of electric showers, mostly during peak hours, considered one of the chief responsible for the high peak in the demand curve between 6.00 and 9.00PM. Given this, the use of solar energy, through solar heating systems for domestic use, meets this purpose. After the analysis of the average monthly consumption of electricity provided by the supplier AES Sul in the period of one year in a residential complex in the city of Canoas – RS, it was possible to estimate the cost of using electric showers in that location, per household, which was between 25 to 30% of the electricity bill. The production of thermal energy through solar heating systems for preheating domestic hot water was simulated using the TRNSYS software for various system configurations (collector area and storage capacity). The relationship between energy demand for water heating and energy produced by SAS was parameterized using the concept of monthly and annual solar fraction, considering a minimum temperature of hot water of 40 ° C, and a profile of consumption corresponding to the average occupancy rate of households at the site. The climatic data required for the simulation were obtained from the typical meteorological year (TMY) to Porto Alegre and the results of several simulations showed that it is possible to get direct savings to the consumer up to 58% of energy consumed by electric shower and energy savings estimated at 12,399 kWh for the electricity system over a period of 20 years. These results can be improved by reducing the unit cost of SAS or through incentives from lowering the cost of expanding the capacity of the electric grid by suppliers, resulting from the change of the system load profile.

La presente dissertazione investiga la possibilità di ottimizzare l’uso di energia a bordo di una nave per trasporto di prodotti chimici e petrolchimici. Il software sviluppato per questo studio può essere adattato a qualsiasi tipo di nave. Tale foglio di calcolo fornisce la metodologia per stimare vantaggi e miglioramenti energetici, con accuratezza direttamente proporzionale ai dati disponibili sulla configurazione del sistema energetico e sui dispositivi installati a bordo. Lo studio si basa su differenti fasi che permettono la semplificazione del lavoro; nell’introduzione sono indicati i dati necessari per svolgere un’accurata analisi ed è presentata la metodologia adottata. Inizialmente è fornita una spiegazione sul layout dell’impianto, sulle sue caratteristiche e sui principali dispositivi installati a bordo. Vengono dunque trattati separatamente i principali carichi, meccanico, elettrico e termico. In seguito si procede con una selezione delle principali fasi operative della nave: è seguito tale approccio in modo da comprendere meglio la ripartizione della richiesta di potenza a bordo della nave e il suo sfruttamento. Successivamente è svolto un controllo sul dimensionamento del sistema elettrico: ciò aiuta a comprendere se la potenza stimata dai progettisti sia assimilabile a quella effettivamente richiesta sulla nave. Si ottengono in seguito curve di carico meccanico, elettrico e termico in funzione del tempo per tutte le fasi operative considerate: tramite l’uso del software Visual Basic Application (VBA) vengono creati i profili di carico che possono essere gestiti nella successiva fase di ottimizzazione. L’ottimizzazione rappresenta il cuore di questo studio; i profili di potenza ottenuti dalla precedente fase sono gestiti in modo da conseguire un sistema che sia in grado di fornire potenza alla nave nel miglior modo possibile da un punto di vista energetico. Il sistema energetico della nave è modellato e ottimizzato mantenendo lo status quo dei dispositivi di bordo, per i quali sono considerate le configurazioni di “Load following”, “two shifts” e “minimal”. Una successiva investigazione riguarda l’installazione a bordo di un sistema di accumulo di energia termica, così da migliorare lo sfruttamento dell’energia disponibile. Infine, nella conclusione, sono messi a confronto i reali consumi della nave con i risultati ottenuti con e senza l’introduzione del sistema di accumulo termico. Attraverso la configurazione “minimal” è possibile risparmiare circa l’1,49% dell’energia totale consumata durante un anno di attività; tale risparmio è completamente gratuito poiché può essere raggiunto seguendo alcune semplici regole nella gestione dell’energia a bordo. L’introduzione di un sistema di accumulo termico incrementa il risparmio totale fino al 4,67% con un serbatoio in grado di accumulare 110000 kWh di energia termica; tuttavia, in questo caso, è necessario sostenere il costo di installazione del serbatoio. Vengono quindi dibattuti aspetti economici e ambientali in modo da spiegare e rendere chiari i vantaggi che si possono ottenere con l’applicazione di questo studio, in termini di denaro e riduzione di emissioni in atmosfera.

This master thesis report has studied several methods to improve the energy consumption of an electric vehicle equipped with two permanent magnet synchronous motors. Two driving torque distribution maps are developed based on efficiency map and load transfer, respectively. The drive torque distribution map based on the efficiency map shows up to 8.94% energy saving. Two regenerative braking strategies are designed and compared. Both strategies have pure regenerative brake at low decelerations and it is controlled by a modified acceleration pedal map. Strategy 1 does not add more regenerative braking when the brake pedal is pressed thus it is simpler while strategy 2 can blend in more motor torque. Rear axle steering is also studied in terms of contribution to energy consumption and an LQR controller is developed to control the vehicle with rear axle steering.
Denna rapport avhandlar ett examensarbete där flera metoder har studerats för att förbättra energikonsumptionen för ett elektriskt fordon med två permanentmagnetsynkrona motorer. Två fördelningskartor för drivande moment är framtagna baserat på effektivitetskartor och lastöverföring. Fördelningskartorna för drivande moment som är baserat på effektivitet visar upp till 8,94% energiminskning. Två olika regenerativa bromsstrategier är framtagna och jämförda. Båda strategierna har ren regeneration vid låga decelerationer och är reglerat genom modifierat gaspedalsmappning. Strategi 1 ger inte mer regeneration när bromspedalen trycks ned och är då enklare medans strategi 2 kan blanda in mer vridmoment från elmotorn. Bakaxelstyrning är också studerat i termer av dess bidrag till energikonsumption samt en LQR regulator är utvecklad för reglering av fordonets bakaxelstyrning.

Mestrado em Engenharia Electrónica e Telecomunicações
Hoje em dia assistimos a uma grande pressão e esforço no sentido de estimular a conservação de energia, seja devido a limitações económicas, preocupações ambientais, ou normas regulatórias. No topo do consumo de energia está a energia sob a forma de electricidade Para se conseguir incentivar a utilização eficiente da energia é necessário fornecer consciencialização energética. Se os consumidores de elecricidade tiverem acesso a informação detalhada sobre como, quando e que aparelhos estão a consumir energia, estes poderão tomar boas e bem suportadas decisões e anuir mudar os seus hábitos de modo a reduzir o consumo de energia, e por fim, gastar menos dinheiro. O projecto aqui apresentado desenvolve as bases para um aparelho que fornece informação detalhada sobre o consumo de energia eléctrica para uma casa. A informação a ser fornecida deverá ser separada individualmente para virtualmente cada aparelho singular presente. A técnica escolhida para desenvolver o aparelho foi Monitorização Não Intrusiva de Cargas de Aparelhos. A partir de um único ponto de medida o sistema deverá identificar as cargas individuais na casa, o que faz com que o hardware tenda a ser simples e minimal, recaindo a complexidade para o software. O sistema desenvolvido deverá ser de baixo custo e de fácil instalação. O sistema que foi desenvolvido foi capaz de identificar individualmente e com grande sucesso os aparelhos presentes num ambiente controlado. Ao contrário de outros sistemas deste tipo, o sistema apresentado nesta dissertação é capaz de distinguir cargas eletricamente idênticas, através do uso da técnica de Medição Indirecta de Potência implementada através de uma Rede de Sensores Sem Fios.
Nowadays we witness a great pressure and effort in order to stimulate energy conservation, either due to economic constraints, environmental concerns, or regulatory pressures. At the top of the energy consumption is the consumption of energy in the form of electricity. The first step to improve energy utilization efficiency is energy awareness. So if there is some manner to provide the average person information about how he is consuming electricity, he may take it by its own interest, and In fact, if electricity consumers have access to detailed information about how, when and by which devices energy is consumed, they can make good and well supported decisions on how they can change their habits to spend less energy and ultimately spend less money. The project hereby presented, develops the basis for a device that provides detailed information on electrical energy expenditure for a home. The information to be provided aims to be disambiguated for virtually every individual appliance present. The chosen technique to develop such a device was Non-Intrusive Appliance Load Monitoring. The system identifies individual loads from a single measurement point. That makes that the hardware tends to be simple and minimal, passing the complexity to the software. The system aims to be very low cost and easy to deploy. The system developed was able to identify with great success individual appliances in the total load on a controlled environment. Unlike other systems of this type, the system presented in this dissertation has the ability of disambiguating electrically identical loads, by the use of the technique of Indirect Power Sensing deployed with a Wireless Sensor Network

AbstractIn many small and medium-sized businesses in rural–urban areas, delivery services to and from customers, suppliers, and distributed locations are required regularly. In contrast to purely urban commercial centres, the distances here are larger. The aim of this paper is to identify opportunities for substituting combustion-engine logistics with lightweight electric commercial vehicles and the limitations thereto, describing an energy efficiency comparison and improvement process for a defined logistics application. Thus, the area of Heilbronn-Franconia and its transport conditions are presented as examples to compare the use case to standard driving cycles. Then the logistic requirements of Heilbronn UAS (University of Applied Science) locations and the available vehicles as well as further electric vehicle options are depicted. Options are discussed for the additional external payload in search of transport volume optimisation without increasing the vehicle floor space. To this end, simulation models are developed for the aerodynamic examination of the enlarged vehicle body and for determining energy consumption. Consumption and range calculation lead to vehicle concept recommendations. These research activities can contribute to the transformation of commercial electro mobility in rural and urban areas in many parts of Germany and Europe.

This paper describes a study starting from an analysis of typical energy demand profiles in a hospital setting followed by the feasibility study of a cogeneration system (CGS). The concept is a future autonomous system for the combined generation of electrical, heating and cooling energy in the hospital. The driving cogeneration units are two high-efficiency gas engines; this is used to produce the electrical and heat energy. Gas engine is used as a driving unit because of high needs for electrical and heating energy. The natural gas-fuelled reciprocating engine is used to generate 735kW of power. In our case electrical energy will be used only in the Hospital. A deficit in electricity can be also purchased from the public network. The generated steam will be used to drive three steam-fired absorption chillers and delivered to individual consumers of heat. This system is capable of doing simultaneous heating and cooling. No obstacles were recognized for the technical feasibility of CGS. The average ratio between electric and thermal load in the Hospital is suitable to make CGS system operate. A feasibility analysis performed for a non-optimized CGS system predicted a large potential for primary energy saving.

Often, available power from an in-vehicle energy storage system is governed by thermal limitations. Modeling of battery pack thermal response is crucial to managing its cooling system energy consumption and estimating available charge/discharge power for future locomotive tractive and regenerative effort. Active cooling through forced air flow was simulated using computer-aided design of the battery pack and its enclosure. Module scaled (series string of 54 12V batteries) testing and modeling of both air flow and temperature distribution was performed and validated for sealed lead acid carbon batteries. A controller area network and data logger collected temperature data from 218 sensors placed throughout a battery pack module during electrical loading for both switcher and over-the-road cycles while under various environmental thermal loadings. A blower on-off control algorithm was optimized to minimize energy consumption and implemented based on temperature array statistics.

Data centers are facilities that primarily contain electronic equipment used for data processing, data storage, and communications networking. Regardless of their use and configuration, most data centers are more energy intensive than other buildings. The continuous operation of Information Technology equipment and power delivery systems generates a significant amount of heat that must be removed from the data center for the electronic equipment to operate properly. Since data centers spend up to half their energy on cooling, cooling systems becomes a key factor for energy consumption reduction strategies and alternatives in data centers. This paper presents a theoretical analysis of an absorption chiller driven by solar thermal energy as cooling plant alternative for data centers. Source primary energy consumption is used to compare the performance of different solar cooling plants with a standard cooling plant. The solar cooling plants correspond to different combinations of solar collector arrays and thermal storage tank, with a boiler as source of energy to ensure continuous operation of the absorption chiller. The standard cooling plant uses an electric chiller. Results suggest that the solar cooling plant with flat-plate solar collectors is a better option over the solar cooling plant with evacuated-tube solar collectors. However, although solar cooling plants can decrease the primary energy consumption when compared with the standard cooling plant, the net present value of the cost to install and operate the solar cooling plants are higher than the one for the standard cooling plant.

The Energy Information Administration of the United States Department of Energy projects that more than 80% of the energy consumption of the U.S. by 2035 will come from fossil fuels. This projection should be the fuel to promote projects related to renewable energy in order to reduce energy consumption from fossil fuels to avoid their undesirable consequences such as carbon dioxide emissions. Since solar radiation match pretty well building cooling demands, solar cooling systems will be an important factor in the next decades to meet or exceed the green gases reduction that will be demanded by the society and regulations in order to mitigate environmental consequences such as global warming. Solar energy can be used as source of energy to produce cooling through different technologies. Solar thermal energy applies to technology such as absorption chillers and desiccant cooling, while electricity from solar photovoltaic can be used to drive vapor compression electric chillers. This study focuses on the comparison of a Solar Thermal Cooling System that uses an absorption chiller driven by solar thermal energy, and a Solar Photovoltaic Cooling System that uses a vapor compression system (electric chiller) driven by solar electricity (solar photovoltaic system). Both solar cooling systems are compared against a standard air cooled cooling system that uses electricity from the grid. The models used in the simulations to obtain the results are described in the paper along with the parameters (inputs) used. Results are presented in two figures. Each figure has one curve for the Solar Thermal Cooling System and one for the Solar Photovoltaic Cooling System. One figure allows estimation of savings calculated based the net present value of energy consumption cost. The other figure allows estimating primary energy consumption reduction and emissions reduction. Both figures presents the result per ton of refrigeration and as a function of area of solar collectors or/and area of photovoltaic modules. This approach to present the result of the simulations of the systems makes these figures quite general. This means that the results can be used to compare both solar cooling systems independently of the cooling demand (capacity of the system), as well as allow the analysis for different sizes of the solar system used to harvest the solar energy (collectors or photovoltaic modules).

Abstract The energy management strategy plays a critical role in scheduling the operations and enhancing the overall efficiency for electric vehicles. This paper proposes an effective model predictive control-based (MPC) energy management strategy to simultaneously control the battery thermal management system (BTMS) and the cabin air conditioning (AC) system for electric vehicles (EVs). We aim to improve the overall energy efficiency, while retaining soft constraints from both BTMS and AC systems. It is implemented by optimizing the operation and discharging schedule to avoid peak load and by directly utilizing the regenerative power instead of recharging. Compared to the systematic performance without any control coordination between BTMS and AC, results reveal that there are a 4.3% reduction for the recharging energy, and a 6.5% improvement for the overall energy consumption that gained from the MPC-based energy management strategy. Overall the MPC-based energy management is a promising solution to enhance the efficiency for electric vehicles.

Electric vehicle (EV) transmission technology—crucial for battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs)—is developing quickly and customers want good performance at a low cost. Single-speed gearboxes are popular in electric drive systems due to their simple and cost-effective configuration. However, multispeed gearboxes are being taken to market due to their higher low-speed torque, dynamic performance, and energy efficiency. Unsettled Technology Areas in Electric Propulsion Systems reviews the economic drivers, existing techniques, and current challenges of EV transmission technology—including torque interruption during shifting; thermal and sealing issues; and noise, vibration, and harshness (NVH). This report discusses the pros and cons for both single-speed and multispeed gearboxes with numerical analysis.

Lighting accounts for approximately 15 % of the global electric energy consumption and 5 % of greenhouse gas emissions. Growing economies, higher user demands for quality lighting and rebound effects as a result of low priced and more versatile electric lighting continuously still lead to an absolute increase of lighting energy consumption. More light is used, often less consciously.

Population growth, increasing prosperity and changing consumer habits globally are increasing demand for consumer electronics. Further to this, rapid changes in technology, falling prices and consumer appetite for better products have exacerbated e-waste management challenges and seen millions of tons of electronic devices become obsolete. This rapid literature review collates evidence from academic, policy focussed and grey literature on e-waste management in Africa. This report provides an overview of constitutes e-waste, the environmental and health impacts of e-waste, of the barriers to effective e-waste management, the opportunities associated with effective e-waste management and of the limited literature available that estimate future volumes of e-waste. Africa generated a total of 2.9 million Mt of e-waste, or 2.5 kg per capita, the lowest regional rate in the world. Africa’s e-waste is the product of Local and imported Sources of Used Electronic and Electrical Equipment (UEEE). Challenges in e-waste management in Africa are exacerbated by a lack of awareness, environmental legislation and limited financial resources. Proper disposal of e-waste requires training and investment in recycling and management technology as improper processing can have severe environmental and health effects. In Africa, thirteen countries have been identified as having a national e-waste legislation/policy.. The main barriers to effective e-waste management include: Insufficient legislative frameworks and government agencies’ lack of capacity to enforce regulations, Infrastructure, Operating standards and transparency, illegal imports, Security, Data gaps, Trust, Informality and Costs. Aspirations associated with energy transition and net zero are laudable, products associated with these goals can become major contributors to the e-waste challenge. The necessary wind turbines, solar panels, electric car batteries, and other "green" technologies require vast amounts of resources. Further to this, at the end of their lifetime, they can pose environmental hazards. An example of e-waste associated with energy transitions can be gleaned from the solar power sector. Different types of solar power cells need to undergo different treatments (mechanical, thermal, chemical) depending on type to recover the valuable metals contained. Similar issues apply to waste associated with other energy transition technologies. Although e-waste contains toxic and hazardous metals such as barium and mercury among others, it also contains non-ferrous metals such as copper, aluminium and precious metals such as gold and copper, which if recycled could have a value exceeding 55 billion euros. There thus exists an opportunity to convert existing e-waste challenges into an economic opportunity.

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.

In recent years automobile manufacturers focused on an increasing degree of electrification of the powertrains with the aim to reduce pollutants and CO2 emissions. Despite more complex design processes and control strategies, these powertrains offer improved fuel exploitation compared to conventional vehicles thanks to intelligent energy management. A simulation study is here presented aiming at developing a new control strategy for a P3 parallel plug-in hybrid electric vehicle. The simulation model is implemented using vehicle modeling and simulation toolboxes in MATLAB/Simulink. The proposed control strategy is based on an alternative utilization of the electric motor and thermal engine to satisfy the vehicle power demand at the wheels (Efficient Thermal/Electric Skipping Strategy - ETESS). The choice between the two units is realized through a comparison between two equivalent fuel rates, one related to the thermal engine and the other related to the electric consumption. An adaptive function is introduced to develop a charge-blended control strategy. The novel adaptive control strategy (A-ETESS) is applied to estimate fuel consumption along different driving cycles. The control algorithm is implemented on a dedicated microcontroller unit performing a Processor-In-the-Loop (PIL) simulation. To demonstrate the reliability and effectiveness of the A-ETESS, the same adaptive function is built on the Equivalent Consumption Minimization Strategy (ECMS). The PIL results showed that the proposed strategy ensures a fuel economy similar to ECMS (worse of about 2% on average) and a computational effort reduced by 99% on average. This last feature reveals the potential for real-time on-vehicle applications.

Hybrid electric vehicles (HEVs) represent one of the main technological options for reducing vehicle CO2 emissions, helping car manufacturers (OEMs) to meet the stricter targets which are set by the European Green Deal for new passenger cars at 80 g CO2/km by 2025. The optimal power-split between the internal combustion engine (ICE) and the electric motor is a challenge since it depends on many unpredictable variables. In fact, HEV improvements in fuel economy and emissions strongly depend on the energy management strategy (EMS) on-board of the vehicle. Dynamic Programming approach (DP), direct methods and Pontryagin’s minimum principle (PMP) are some of the most used methodologies to optimize the HEV power-split. In this paper two online strategies are evaluated: an Adaptive-RuleBased (A-RB) and an Adaptive-Equivalent Consumption Minimization Strategy (A-ECMS). At first, a description of the P2 HEV model is made. Second, the two sub-optimal strategies are described in detail and then implemented on the HEV model to derive the fuel-optimal control strategy managing the power split between the thermal and electric engine to satisfy the driver's power request, including the engine on/off operating mode and the best gear selection. Finally, the two proposed strategies are tested on different driving cycles and then compared to other commercial strategies available in literature, such as the Equivalent Consumption Minimization Strategy (ECMS) and a RuleBased (RB) strategy. The results show that the A-ECMS is more conservative in terms of state of charge (SoC) compared to the A-RB. In fact, in the A-ECMS the SoC is always within the admissible range with considerable margin from the upper and lower limits for tested cycles, while in the A-RB a deep discharge of the battery is allowed. This behavior leads to a better fuel consumption of the A-RB compared to the A-ECMS, both in the WLTC and in the FTP-75 cycle.