• Energy Research
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Energy poverty is a multidimensional and complex phenomenon, and several indicators have been developed to evaluate and quantify it. However, often greater complexity does not mean greater precision. In the case of Chile, the Energy Poverty Network established the Three-dimensional and Territorial Indicator of Energy Poverty (EPTTI in Spanish) to assess the energy poverty situation of Chilean families. The EPTTI is based on a multidimensional approach with 10 indicators. Although, their evaluation involves resources that may hinder a practical application. This study analyzed the consistency between the individual responses of an indicator and the adapted EPTTI evaluation, using a database of 641 families. The results show that the excessive energy expenditure and the type and energy source of heating systems indicators are the variables with the greatest influence on energy poverty assessments. These results served to both propose simplified approaches for energy poverty assessment with the indicator, and establish policies of action that regional governments should address to reduce the situation of energy poverty Confort ambiental y pobreza energ´etica (+CO-PE)” of the University of the Bío-Bío, the Thematic Network 722RT0135 “Red Iberoamericana de Pobreza Energ´etica y Bienestar Ambiental” (RIPEBA) National Agency for Research and Development (ANID, in Spanish) Thematic Networks of the CYTED Program for 2021 Universidad de Granada / CBUA

Global climate change is changing meteorological parameters and climate zones for building in different parts of the world, as well as changing energy consumption by dwellings. Therefore, in this study, changes in climatic zones for building in three regions in southern Chile have been analysed under the conditions of two future climatic scenarios (RCP2.6 and RCP8.5). On average, the temperature will increase by +0.68 °C and +1.51 °C by 2050–2065 in the study region for scenarios RCP2.6 and RCP8.5, respectively. This will cause a decrease in the annual heating degree-days values. In 72% of cities (RCP2.6) and in 92% of cities (RCP8.5), climate zones for building will be replaced by warmer ones. Consequently, the possibility of applying the current building standard of the country in future climatic conditions has been questioned. Finally, it was found that the heating energy consumption of a single-family house will decrease by 13% and 27% on average for the RCP2.6 and RCP8.5 scenarios, respectively. © 2020

Abstract Energy performance of buildings generally assesses the energy consumption of buildings such as heating, domestic heat water, ventilation systems, etc. However, this approach is based on the first law of thermodynamics and considers only the quantity of energy used without considering its ‘quality’ and leads to a lack of information about the energy conversion processes. This is particularly true in the new low-energy buildings where sometimes high temperatures sources are used to meet low-temperature needs. The exergy analysis of a system, based on first and second thermodynamic laws, can be used to overcome this. In this work, it is proposed to compare the energy and the exergy consumption and the related CO2 emissions of several kinds of buildings to determine the best systems in terms of energy and exergy needs. The energy demand calculations are performed using the official software available in Belgium and some assumptions are implemented to consider the exergy approach. As exergy calculations require a reference state, some different climatic conditions are also investigated. Finally, some conclusions are discussed to rank the sources of energy and their related exergy losses.

Abstract Heating, ventilation, and air conditioning systems help maintain the appropriate level of thermal comfort and air quality in buildings. To this end, the energy supply of these systems must be guaranteed. However, continuous efforts are required to improve the energy efficiency of this system and reduce greenhouse gas emissions. In the zero-emission building approach, the use of thermoelectric devices has been proposed to meet the heating/cooling needs in the building and help in flexibly changing the operating conditions according to the user's needs. In this study, an experimental setup was developed consisting of a multipurpose thermoelectric system that is directly powered by a solar photovoltaic panel. The heating mode was designed for space heating, whereas the cooling mode was tailored to an adiabatic box that could cool food and beverages. The results of this study will facilitate the practical use of this device in the future by directly connecting the thermoelectric system to the room and evaluating the response of the system to temperature changes requested by the user. This system has a high potential for delivering heating and cooling loads, achieving a coefficient of performance of 1.6 in the heating mode and 0.8–1.1 in the cooling mode. These results are promising given the current need to reduce negative environmental impacts in the building sector yet maintaining the same level of thermal comfort.

Abstract Many studies are focused on the diagnosis of fuel poverty. However, its prediction before occupying households is a developing research area. This research studies the feasibility of implementing the Fuel Poverty Potential Risk Index (FPPRI) in different climate zones of Chile by means of regression models based on artificial neural networks (ANNs). A total of 116,640 representative case studies were carried out in the three cities with the largest population in Chile: Santiago, Concepcion, and Valparaiso. Apart from energy price (EP) and income (IN), 9 variables related to the morphology of the building were considered in approach 1. Furthermore, approach 2 was developed by including comfort hours (NCH). A total of 84 datasets were combined considering both approaches and the 5 most unfavourable deciles according to the income level of Chilean families. The results of both approaches showed a better performance in the use of individual models for each climate (MLPC, MLPS, and MLPV), and the dataset with all deciles (Full) could be used. Regarding the influence of the input variables on the models, IN was the most determinant, and NCH becomes important in approach 2. The potential of using this methodology to allocate social housing would guarantee the main objective of the country: the reduction of fuel poverty in the roadmap for 2050.

Abstract Over a three years period, an aquifer thermal energy storage system was monitored in combination with a heat pump for heating and cooling of the ventilation air in a Belgian hospital. The installation was one of the first and largest ground source heat pump systems in Belgium. Groundwater flows and temperatures were monitored as well as the energy flows of the heat pumps and the energy demand of the building. The resulting energy balance of the building showed that the primary energy consumption of the heat pump system is 71% lower in comparison with a reference installation based on common gas-fired boilers and water cooling machines. This corresponds to a CO2-reduction of 1280 ton over the whole measuring period. The overall seasonal performance factor (SPF) for heating was 5.9 while the ATES system delivered cooling at an efficiency factor of 26.1. Furthermore, the economic analysis showed an annual cost reduction of k€ 54 as compared to the reference installation, resulting in a simple payback time of 8.4 years, excluding subsidies.

Abstract Model Predictive Control (MPC) has shown significant energy savings potential in the operation of building energy systems, yet it needs accurate and simple models for optimization. In hybrid geothermal systems the source-side temperatures affect the system efficiency and its operational feasibility. Since the ground dynamics are rather slow, simplifications such as considering a constant coefficient of performance (COP) are made. We evaluate the added value of including a short-term dynamic borefield model to the controller. Simulations are performed in a heating-dominated building equipped with a hybrid geothermal system for two winter weeks. We consider 4 different modeling strategies where the formulation of the COP and the return fluid temperature from the borefield is varied in complexity. Results show that using a constant COP results in a bang-bang behavior of the heat pump, while with an accurate prediction of the COP the operation is smoother, saving 0.46%, 1.86% and 2.71% for low, average and high electricity-to-gas price ratios respectively. Including a short-term borefield model avoids shutting down the heat pump due to safety constraints which saves up to 8.12% more money while the use of the ground-source is quintupled. Despite reducing the optimization iteration number by almost 18%, simulation time is increased.

Abstract This paper presents the SOLEN integrated online tool, dedicated to citizens and local authorities. This methodology, developed to allow precise energy assessment (heating, cooling, ventilation, lighting, appliances, and cooking but also local production of renewable energy) of household energy uses, is firstly introduced. SOLEN uses a typological classification of buildings and thermal simulations. Many parameters are defined and taken into account to capture the specificities of numerous types of buildings exhaustively (e.g. type of buildings; number of floors; common ownership; orientation; thermal performances of the walls, floors, roofs, and windows; and ventilation type). These results related to building energy consumption are then crossed, in an integrated approach, with several indicators of urban sustainability, to take into account in the balance of the impact of the location of buildings on transportation energy consumption or the impact of the urban form on the production of solar renewable energy. This tool makes accessible to a large non-specialized audience the results of a three-year scientific research study in Wallonia (Belgium) and was awarded an Energy Globe Award (Belgium) in 2014. The first feedback from users is presented to conclude this contribution.