• Energy Research

El objetivo principal del presente artículo es mostrar y dar a conocer las aplicaciones de la edificación bioclimática, sus ventajas y características. Para ello, se muestra el proyecto de Construcción de un Edificio Inteligente de “Energía Convencional Cero” (“Bioclimático”) de unos 1700 m2 en el Campus de la Universidad de Extremadura en Badajoz. Se pondrán en práctica los conceptos sobre ahorro y eficiencia energética en la edificación, así como la integración de las energías renovables en el edificio PETER. Además se mostrará como es posible en ciudades de clima extremo (como es la ciudad de Badajoz, con necesidad de calefacción en invierno y de refrigeración en verano), climatizar edificios aplicando medidas que minimizan el consumo energético. Finalmente, se lleva a cabo un proceso de simulación energética que permite comprobar el comportamiento energético del edificio. The present article is intended to show the main features, advantages and applications of bioclimatic architecture as well as the the integration of renewable energies ito the edification. For such purpose, the Project of an approximate 1 700 m2 intelligent zeroconventional- energy (“Bioclimatic”) building (referred to as PETER Project (Experimental Transborder Park on Renewable Energies)), to be located in the Campus of the University of Extremadura in Badajoz, is described. Specific principles directly relating building design, like energy saving, energy efficient and integration of renewable energy sources, are put in practice. In addition will be shown as it is possible in cities of extreme climate (as it is the city of Badajoz, with necessity of heating in winter and refrigeration in summer), to acclimate buildings applying measures that diminish the power consumption. Finally, a description of the energy response of the building is carried out via computer simulation techniques. Departamento de Ingeniería de Diseño y Proyectos

Historic, listed, or unlisted, buildings account for 30% of the European building stock. Since they are complex systems of cultural, architectural, and identity value, they need particular attention to ensure that they are preserved, used, and managed over time in a sustainable way. This implies a demand for retrofit solutions able to improve indoor thermal conditions while reducing the use of energy sources and preserving the heritage significance. Often, however, the choice and implementation of retrofit solutions in historic buildings is limited by socio-technical barriers (regulations, lack of knowledge on the hygrothermal behaviour of built heritage, economic viability, etc.). This paper presents the approach devised in the IEA-SHC Task 59 project (Renovating Historic Buildings Towards Zero Energy) to support decision makers in selecting retrofit solutions, in accordance with the provision of the EN 16883:2017 standard. In particular, the method followed by the project partners to gather and assess compatible solutions for historic buildings retrofitting is presented. It focuses on best practices for walls, windows, HVAC systems, and solar technologies. This work demonstrates that well-balanced retrofit solutions can exist and can be evaluated case-by-case through detailed assessment criteria. As a main result, the paper encourages decision makers to opt for tailored energy retrofit to solve the conflict between conservation and energy performance requirements.

New technological, societal and legislative developments are necessary to support transitions to low-carbon energy systems. The building sector is responsible for almost 36% of the global final energy and 40% of CO2 emissions, so this sector has high potential to contribute to the expansion of positive energy districts. With this aim, a new digital Geographic Information System (GIS) platform has been developed to quantify the energy savings obtained through the implementation of refurbishment measures in residential buildings, including solar thermal collectors and geothermal technologies and assuming the postal district as the representative unit for the territory. Solar resources have been estimated from recently updated solar irradiation maps, whereas geothermal resources have been estimated from geological maps. Urbanistic data have been estimated from official cadastre databases. For representative buildings, the annual energy demand and savings are obtained and compared with reference buildings, both for heating and cooling. The GIS platform provides information on average results for each postal district, as well as estimates for buildings with particular parameters. The methodology has been applied to the Asturian region, an area of about 10,600 km2 on the Cantabrian coast of Spain, with complex orography and scattered population, qualified as a region in energy transition. High rehabilitation potentials have been achieved for buildings constructed before the implementation of the Spanish Technical Building Code of 2006, being higher for isolated houses than for collective buildings. Some examples of results are introduced in specific localities of different climatic zones.

Abstract A new simulation platform has been created to quantify the energy response of existing residential buildings with different refurbishment strategies. This tool has been developed as a multi-step form wizard to select the simulation options. The energy improvements have been calculated through the coupling between TRNSYS and GenOpt. Output information is: annual thermal loads, monthly loads reductions and cost estimations. Four refurbishment options have been evaluated considering different combined actions. The renovation of the building envelope is the most expensive action with the highest annual savings while the behavior of inhabitants is the cheapest option with the lowest annual savings.

Building occupancy is one of the relevant variables to understand the energy performance of buildings and to reduce the current gap between simulation-based and actual energy performance. In this study, the occupancy of a classroom in an educational center monitored over a full year was experimentally assessed. The classroom had different occupancy levels during the school year, with a theoretical minimum of eleven students, and no occupancy during vacations and weekends. Different variables such as indoor air temperature, relative humidity, CO2 concentration, overall electrical energy consumption of the educational center, electrical energy consumption of the building in which the monitored classroom is located, and heating energy consumption were recorded. We analyzed which of these variables were possible indicators of classroom occupancy, using the school timetable as a theoretical reference value for the validation of the results. Based on previous studies, one-hour moving averages are used to better identify the occupancy patterns by smoothing the fluctuations that are not a consequence of a change in the classroom occupancy. Histograms of each variable are used to identify the variable ranges associated within the occupancy: occupied or empty. The concentration of CO2 and electric measurements, identified in previous works as suitable to assess the occupancy patterns of rooms like offices with lower levels of occupancy, are recognized as potential occupancy indicators. It is therefore concluded that a higher level of space occupancy does not affect the result, and the same variables are identified as potential occupancy indicators.

Abstract The application of the European directives related to the energy consumption of existing buildings leads to the integration of efficient techniques into the refurbishment actions. This procedure allows reaching high energy savings and reducing pollutant emissions. The identification of the energy consumption profile of the building stocks is a necessary step to evaluate the impact of retrofit measures. With this aim, the energy performance of representative dwellings has been analyzed to develop a citizen-oriented platform. This representativeness has been chosen through one parametric matrix that characterizes the residential building stock of Madrid. Different refurbishment strategies have been highlighted to assess the energy savings in comparison with the initial situation. Two building cases and three boundary conditions have been selected to develop six TRNSYS models. The energy impact produced by the implementation of selected refurbishment strategies has been evaluated through a sensitivity analysis. Batteries of simulations have been executed coupling the TRNSYS models with GenOpt. The most influential strategies are the typology of facades, insulation at the roof, variable set point temperatures, better glazing and exterior summer shading over the windows. Building performances to minimize the annual thermal needs and one economic study have been developed.

The analysis of building characteristics indicates that there are some uncertainties influencing its energy performance: Environment, volumetry or operating conditions. It is important to have a low-cost system that performs this analysis and energy management by optimizing the coupling between production and consumption. Knowing the relationship between the annual thermal needs with different construction parameters can help to define this system and allow understanding the expected heating and cooling consumption based on easily available information. In this work, a numerical methodology has been applied to estimate the thermal loads of a building without internal gains. For this purpose, a simulation environment has been developed to execute a sensitivity analysis through the interconnection between TRNSYS 16.1 and GenOpt programs. Volumetry, building materials according to Spanish regulations and percentage of external windows are evaluated as analysis variables of the parametric study. Heating, and cooling loads have been calculated to quantify their influence: Older regulations imply higher annual loads; the increase in building height and area reduces the annual thermal loads and higher percentages of glazing on the external façades imply higher annual demands, particularly in the east and west orientations; the variation of the envelope results in the most influential factor. Finally, a statistical study has been performed to assess the annual trends: Heating trends point to more stability with two defined intervals, while cooling trends are more asymmetric.

Abstract In this work, the performance of a real ventilated facade has been investigated both experimentally and numerically. The studied facade is south oriented and belongs to a building located in Almeria, a city in the South of Spain with warm Mediterranean climate. Experimental data, based on temperature, heat fluxes and incident radiation on the facade have been collected during one year. The experimental data have been used to analyse the energy performance of the facade during the summer and the winter periods. The results show that in warm climates with high levels of solar radiation, the ventilated facade can play an important role in reducing the heating and cooling thermal loads as long as the outdoor temperatures are not extreme. Additionally, a model based on fluid dynamic simulation techniques is proposed. The comparison with experimental data shows the importance of including the reflected radiation from the ground in the thermal modelling of the facade. The proposed model can predict temperatures and heat fluxes to the room with deviations lower than 10%.