A review on buildings energy consumption information

The rapidly growing world energy use has already raised concerns over supply difficulties, exhaustion of energy resources and heavy environmental impacts (ozone layer depletion, global warming, climate change, etc.). The global contribution from buildings towards energy consumption, both residential and commercial, has steadily increased reaching figures between 20% and 40% in developed countries, and has exceeded the other major sectors: industrial and transportation. Growth in population, increasing demand for building services and comfort levels, together with the rise in time spent inside buildings, assure the upward trend in energy demand will continue in the future. For this reason, energy efficiency in buildings is today a prime objective for energy policy at regional, national and international levels. Among building services, the growth in HVAC systems energy use is particularly significant (50% of building consumption and 20% of total consumption in the USA). This paper analyses available information concerning energy consumption in buildings, and particularly related to HVAC systems. Many questions arise: Is the necessary information available? Which are the main building types? What end uses should be considered in the breakdown? Comparisons between different countries are presented specially for commercial buildings. The case of offices is analysed in deeper detail

Decision system based on neural networks to optimize the energy efficiency of a petrochemical plant

The energy efficiency of industrial plants is an important issue in any type of business but particularly in the chemical industry. Not only is it important in order to reduce costs, but also it is necessary even more as a means of reducing the amount of fuel that gets wasted, thereby improving productivity, ensuring better product quality, and generally increasing profits. This article describes a decision system developed for optimizing the energy efficiency of a petrochemical plant. The system has been developed after a data mining process of the parameters registered in the past. The designed system carries out an optimization process of the energy efficiency of the plant based on a combined algorithm that uses the following for obtaining a solution: On the one hand, the energy efficiency of the operation points occurred in the past and, on the other hand, a module of two neural networks to obtain new interpolated operation points. Besides, the work includes a previous discriminant analysis of the variables of the plant in order to select the parameters most important in the plant and to study the behavior of the energy efficiency index. This study also helped ensure an optimal training of the neural networks. The robustness of the system as well as its satisfactory results in the testing process (an average rise in the energy efficiency of around 7%, reaching, in some cases, up to 45%) have encouraged a consulting company (ALIATIS) to implement and to integrate the decision system as a pilot software in an SCADA

Activity and efficiency trends for the residential sector across countries

The residential sector is a major contributor to climate change, accounting for almost a quarter of global energy consumption and a fifth of CO2 emissions in 2019. Since 2000, residential consumption has grown at a sustained rate of 1%/year, driven by the development of emerging economies, despite stagnation in developed countries. The increasing demand for living space, energy services and comfort levels seems difficult to curb, especially in the developing world on its fair attempt to reduce inequality. To understand these trends, this paper analyses the trajectories of key indicators of activity and efficiency in this sector, for emerging and developed regions, as well as for major consuming nations, mainly China, United States, European Union, Russia, India, Japan and Brazil. Despite data limitations, meaningful cross-country comparisons are presented for fuel mixes, energy services and dwelling types. Heating, ventilation and air conditioning (HVAC) systems account for a third of residential consumption and will grow rapidly as increasing wealth in emerging economies allows for satisfying the thermal comfort demand. Economic development will naturally increase housing size and equipment level and reduce household size, and could close the per capita consumption gap between developing and developed regions. Efficiency improvements could reduce the energy use intensity to around 10 koe/m(2) but will not be enough to curb residential consumption. International cooperation, policy support and funding are essential to accelerate development and efficiency gains in developing countries without compromising environmental targets. In the meantime, politicians should focus on decarbonising the energy mix and promoting energy efficiency, while citizens focus on energy conservation to avoid irreversible environmental damage. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Experimental adjustment of the turbulent Schmidt number to model the evaporation rate of swimming pools in CFD programmes

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Water evaporation rate is among the most significant parameters to design and select air con- ditioning systems in buildings with indoor swimming pools. Experimental correlations are today widely used to estimate water evaporation rate, although discrepancies of up to 80% among existing correlations have been shown. An alternative to these empirical methods is the calcu- lation of evaporation rate through computer fluid dynamics techniques. One of the most signif- icant parameters to solve the mass transfer at the air-water interface in these models is the value of the turbulent Schmidt number. Although this value depends on air and water conditions (i.e., temperatures, velocities, and vapour pressure, among others), commercial computer fluid dy- namics programmes set a fixed value by default. This study presents a new value through an experimental adjustment. A total of 40 experimental tests have been performed in a wind tunnel under typical conditions in indoor swimming pools. Afterwards, the adjustment was validated with data from 145 experimental tests reported in the scientific literature. The mean relative error in the evaporation rate using the turbulent Schmidt number was 7%, as against 25% using the value by default. The maximum error was reduced from 35% to 15% in forced convection regime

Urban integration of aeroelastic belt for low-energy wind harvesting

In this modern age low-energy devices are pervasive especially when considering their applications in the built-environment. The multitude of low-energy applications extend from wireless sensors, radio-frequency transceivers, charging devices, cameras and other small-scale electronic devices. The energy consumptions of these devices range in the milliwatt and microwatt scale which is a result of continuous development of these technologies. Thus, renewable wind energy harnessed from the aeroelastic effect can play a pivotal role in providing sufficient power for extended operation with little or no battery replacement. An aeroelastic belt is a simple device composed of a tensioned membrane coupled to electromagnetic coils and power conditioning components. This simplicity of the aeroelastic belt translates to its low cost and overall modularity. The aim of this study is to investigate the potential of integrating the aeroelastic belt into the built environment using Computational Fluid Dynamics (CFD) simulations. The work will investigate the effect of various external conditions (wind speed, wind direction and physical parameters, positioning and sizing) on the performance of the aeroelastic belt. The results from this study can be used for the design and integration of low-energy wind generation technologies into buildings

A review on buildings energy information: Trends, end-uses, fuels and drivers

Buildings are a major contributor to climate change, accounting for one third of global energy consumption and one quarter of CO2 emissions. However, comprehensive information is lacking for the development, evaluation and monitoring of mitigation policies. This paper discusses the remaining challenges in terms of reliability and consistency of the available data. A review of energy use in buildings is presented to analyse its evolution by building types, energy services and fuel sources. Residential buildings are the most consuming, although tertiary expansion requires further analysis to develop sound specific indicators. Heating Ventilation and Air Conditioning (HVAC) systems concentrate 38% of buildings consumption, calling for strengthened standards and incentives for retrofitting. Electrification is rapidly increasing, representing a potential tool for climate change mitigation, if renewable power was promoted. However, energy use in buildings will only curb if global cooperation enables developing nations to break the link between economic growth, urbanisation and consumption. To this aim, efficiency gains both in construction and equipment, decarbonisation of the energy mix and a global awareness on energy conservation are all neededComisión Europea Horizonte 2020 76857

Connecting to smart cities : analyzing energy times series to visualize monthly electricity peak load in residential buildings

Rapidly growing energy consumption rate is considered an alarming threat to economic stability and environmental sustainability. There is an urgent need of proposing novel solutions to mitigate the drastic impact of increased energy demand in urban cities to improve energy efficiency in smart buildings. It is commonly agreed that exploring, analyzing and visualizing energy consumption patterns in residential buildings can help to estimate their energy demands. Moreover, visualizing energy consumption patterns of residential buildings can also help to diagnose if there is any unpredictable increase in energy demand at a certain time period. However, visualizing and inferring energy consumption patterns from typical line graphs, bar charts, scatter plots is obsolete, less informative and do not provide deep and significant insight of the daily domestic demand of energy utilization. Moreover, these methods become less significant when high temporal resolution is required. In this research work, advanced data exploratory and data analytics techniques are applied on energy time series. Data exploration results are presented in the form of heatmap. Heatmap provides a significant insight of energy utilization behavior during different times of the day. Heatmap results are articulated from three analytical perspectives; descriptive analysis, diagnostic analysis and contextual analysis

Desarrollo de la herramienta docente CuadernoDeProblemas. Aplicación a las ciencias y técnicas del frío.

CuadernoDeProblemas (http://cuadernodeproblemas.es) es una herramienta gratuita y online diseñada para resolver los problemas usuales en las materias vinculadas a la ingeniería. La nueva versión 3 incluye características muy adecuadas para su aplicación en las ciencias y técnicas del frío. La apariencia de la herramienta ha sido rediseñada para simular el desarrollo de los problemas en una “hoja de papel”. La aplicación es capaz de obtener las propiedades termofísicas de los fluidos (refrigerantes, sicrometría, etc.). Se han incluido los componentes Tabla y Gráfica, que permiten resolver varias veces el mismo problema modificando de forma paramétrica alguno de los datos del problema. La herramienta está siendo implantada en el marco del departamento de ingeniería energética de la Universidad de Sevilla, donde es utilizada ya en 8 asignaturas, con más de 400 usuarios registrados y más de 3000 problemas creados en la base de datos