The integration of renewable energy and flexible energy sources in buildings brings numerous benefits. However, the integration of new technologies has increased the complexity and despite the ...progress of optimization algorithms and technologies, new research challenges emerge. With the increasing availability of data and advanced modeling tools, stakeholders in the building sector are actively seeking a more comprehensive understanding of the implementation and potential benefits of energy optimization and an extensive up-to-date survey of optimization in the context of buildings and communities is missing in the literature. This study comprehensively reviews over 180 relevant publications on the management and optimization of energy flexibility resources in buildings. The primary objective was to examine and analyze prior research, with emphasis on the used methods, objectives, and scope. The method of content analysis was used to ensure a thorough examination of the existing literature on the subject. It was concluded that multi-objective optimization is crucial to enhance the utilization of flexible resources within individual buildings and communities. Moreover, the study successfully pinpointed key challenges and opportunities for future research, such as the need for accurate data, the complexity of the optimization process, and the potential trade-offs between different objectives.
This paper systematically reviews the techniques and dynamics to study uncertainty modelling in the electric grids considering electric vehicles with vehicle-to-grid integration. Uncertainty types ...and the most frequent uncertainty modelling approaches for electric vehicles are outlined. The modelling approaches discussed in this paper are Monte Carlo, probabilistic scenarios, stochastic, point estimate method and robust optimisation. Then, Scopus is used to search for articles, and according to these categories, data from articles are extracted. The findings suggest that the probabilistic techniques are the most widely applied, with Monte Carlo and scenario analysis leading. In particular, 19% of the cases benefit from Monte Carlo, 15% from scenario analysis, and 10% each from robust optimisation and the stochastic approach, respectively. Early articles consider robust optimisation relatively more frequent, possibly due to the lack of historical data, while more recent articles adopt the Monte Carlo simulation approach. The uncertainty handling techniques depend on the uncertainty type and human resource availability in aggregate but are unrelated to the generation type. Finally, future directions are given.
An indoor climate impacts human comfort, well-being, and safety. Therefore, it remains an important topic since, nowadays, people spend a significant amount of time indoors. Additionally, as tropical ...geographical zones become more populated, urbanised, and industrialised, the energy demand for air conditioning will rise significantly. In terms of the indoor climate, hospitals are particularly demanding due to the special needs of their occupants, however there is a paucity of studies about the tropics. Through a systematic analysis of accessible data and peer-reviewed articles, this study performed a quantitative and qualitative review of the scientific studies selected by the defined inclusion and exclusion parameters. A total of 65 tropics-related scientific publications, 28 on indoor thermal comfort and 37 on indoor air quality published between 2000 and 2023, were systematically reviewed. This study’s findings corroborated those from the previous studies, alluding that there is a paucity of scientific studies on the indoor climate conditions of buildings in tropical countries. A total of 42 studies (65%) were conducted in Asia and 15 studies (23%) in Africa. Six studies (9%) were reported in South America and two studies (3%) were obtained from Oceania, Australia. The results indicated that tropical Africa recorded the lowest number of indoor climate studies considering the population indices. Many of the reviewed indoor climate studies employed mixed methods, whereas only very few considered a seasonal approach. Meanwhile, in the developing tropics, only one record was found regarding an indoor climate study of hospitals based on their locations (correlating the outdoor and indoor air quality). Additionally, no record was found regarding the IC studies of hospitals in sub-Saharan Africa, in which, the IC impact on the occupant’s performance, productivity, and behaviour was assessed. Inferably, gaps still exist in the indoor climate of tropical hospitals. The current study highlights the need to improve the indoor climate considerations in the design, siting, awareness, regulations, and policy implementations concerning the hospitals in developing tropical countries. In conclusion, the study emphasises the need for more scientific studies on the indoor climate of tropical hospitals and highlights the relevant areas of the indoor climate studies in future works for considering the climate, environmental, socio-economic, infrastructural, and demographic peculiarities of the tropics for the betterment of hospital indoor climates in developing tropical countries.
Energy demand has been increasing worldwide and the building sector represents a large percentage of global energy consumption. Therefore, promoting energy efficiency in buildings is essential. Among ...all building services, Heating, Ventilation and Air Conditioning (HVAC) systems are significantly responsible for building energy use. In HVAC, ventilation is the key issue for providing suitable Indoor Air Quality (IAQ), while it is also responsible for energy consumption in buildings. Thus, improving ventilation systems plays an important role not only in fostering energy efficiency in buildings, but also in providing better indoor climate for the occupants and decreasing the possibility of health issues in consequence. In the last decades, many energy-efficient ventilation methods are developed by researchers to mitigate energy consumption in buildings. This paper reviews scientific research and reports, as well as building regulations and standards, which evaluated, investigated and reported the development of energy-efficient methods for ventilation in buildings. Besides energy-efficient methods such as natural and hybrid ventilation strategies, occupants’ behaviours regarding ventilation, can also affect the energy demand in buildings. Therefore, the influence of occupants’ behaviour on the energy use and the correlation between ventilation and the occupants’ health and productivity were also considered. The review showed that ventilation is interrelated with many factors such as indoor and outdoor conditions, building characteristics, building application as well as users’ behaviour. Thus, it is concluded that many factors must be taken into account for designing energy-efficient and healthy ventilation systems. Moreover, it should be mentioned that utilizing hybrid ventilation in buildings integrated with suitable control strategies, to adjust between mechanical and natural ventilation, leads to considerable energy savings while an appropriate IAQ is maintained.
Nearly-zero energy buildings are standard for new constructions in the European Union. The challenge for decarbonized cities is retrofitting the existing buildings. Retrofitting the existing ...buildings provides considerable opportunities for improving occupants' comfort and reducing global energy consumption and greenhouse gas emissions. Building retrofit is being considered one of the main approaches to achieve sustainability in the built environment at relatively low-cost and high-uptake rates. Although a broad range of retrofit technologies are readily available, methods to ascertain the most suitable set of retrofit actions for specific projects are still a practical challenge. This article first aims to develop and present a simulation-based multi-objective optimization model, named RETROSIM, to quantitatively assess technology choices in a building retrofit project. RETROSIM is a combination of a building energy simulation model and RETROSIM proprietary optimization engine. Secondly, in this study, RETROSIM is used to evaluate a building retrofit project as a case study to show the functionality of the proposed method. The study initiates with the single optimization of objective functions focusing on the building's characteristics and performance: primary energy consumption, global costs and thermal discomfort hours. Then this methodology is used to study the interaction between these conflicting objectives and evaluate their trade-offs.
Buildings are responsible for a large sharing of energy consumption worldwide. Among all energy services in buildings, heating, ventilation and air conditioning systems not only account for a ...significant part of energy consumption but they are also highly influential on indoor climate and occupants’ satisfaction in consequence. In this paper, four demand-controlled ventilation strategies based on occupancy schedule period, occupancy level and indoor concentration of CO2 in an office room have been studied. The indoor air quality as well as the energy consumption levels associated to each demand-controlled ventilation strategy were assessed through simulations performed using EnergyPlus. The results showed the best suited ventilation strategies for the office room that can provide acceptable level of indoor air quality with the least energy use. Furthermore, three sensitivity analyses were performed in order to assess the influence of changing different criteria on the energy consumption and indoor air quality.
Uma vez que o consumo de combustíveis fósseis provoca impactos ambientais críticos, o desenvolvimento das energias renováveis tem-se tornado uma prioridade em muitos países. Desta forma, as energias ...solar e do vento são comercializadas, enquanto a energia das ondas está ainda nos seus primeiros passos. A energia das ondas é uma ampla fonte de energia limpa, no entanto ainda muitas barreiras e obstáculos têm de ser ultrapassados para ser possível captar a potência real que se encontra armazenada nas ondas oceânicas. Nas décadas recentes, alguns protótipos de conversores de energia das ondas foram construídos e testados, todavia, quase todos foram destruídos passado algum tempo devido à sua incapacidade em resistir às condições adversas dos oceanos. Uma vez que os ensaios laboratoriais são bastante caros e morosos, actualmente é comum recorrer-se a simulações numéricas. Muitos investigadores desenvolveram o seu próprio tanque de ondas numérico com o intuito de avaliar o comportamento das ondas.Esta dissertação de mestrado tem como objetivo desenvolver um tanque de ondas numérico para estimar a propagação de ondas regulares e o seu comportamento na interacção com o fundo do mar, usando a aplicação waves2Foam, desenvolvida no âmbito do software OpenFOAM. Para tal, três cenários e alguns sub-cenários são definidos com base nos diferentes tipos da teoria de Stokes aplicável a ondas. Os resultados mostram que o waves2Foam é capaz de simular relativamente bem todos os tipos de rebentamento de ondas, ainda que com algumas limitações. A reflexão das ondas na fronteira de saída foi relatada em muitos estudos, pelo que a aplicação waves2Foam possui um método de absorção chamado zona de relaxamento, que impede a reflexão das ondas a partir da fronteira de saída do tanque. Finalmente, os resultados do presente estudo demonstram que o waves2Foam é uma poderosa ferramentas para simulação numérica da propagação de ondas e sua absorção. Conclui-se ainda que o OpenFOAM tem algumas limitações, como por exemplo, é incapaz de simular ondas com declive superior a 0.05, casos em que foram observados alguns problemas tais como o amortecimento da onda.
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