Bioclimatic rehabilitation of an open market place by a computational fluid dynamics simulation assessment

These days urban design of open spaces is strongly related to bioclimatic techniques and practices. It is here presented the procedure of a bioclimatic study by the use of simulation tools. The area of an open market place is characterized of decreased human thermal comfort conditions during summer time. The employment of computational fluid dynamics has contributed in the understanding of what interventions should be made at the open space in order to succeed the defined thermal related targets. Table of the proposed rehabilitation explains what the interventions would contribute in the improvement of the local environment.The authors greatly acknowledge the support of the Mayor of Eordaia Mrs Paraskevi Vrizidou during all simulation stages. ANSYS-CFD simulations were carried out in the framework of student instruction and demonstration of the Department of Environmental Engineering, Democritus University of Thrace in Greece

Using cool paving materials to improve microclimate of urban areas e Design realization and results of the flisvos project

The present paper deals with the application of 4500 m2 of reflective pavements in an urban park in the greater Athens area. The aim was to improve thermal comfort conditions, reduce the intensity of heat island and improve the global environmental quality in the considered area. To our knowledge, this has been the largest application of cool pavements in urban areas in the world. To evaluate the thermal impact of cool paving materials, specific and detailed measurements of the climatic conditions in the park have been performed before and after the installation of the new materials. Validated computerized fluid dynamics techniques have been used to homogenize the boundary conditions occurring during the two experiments and to perform direct comparisons of the climatic quality in the park. It was estimated that the use of cool paving materials contributes to the reduction of the peak ambient temperature during a typical summer day, by up to 1.9 K. At the same time, the surface temperature in the park was decreased by 12 K, while comfort conditions have been improved considerably. It is concluded that the use of reflective paving materials is a very efficient mitigation technique to improve thermal conditions in urban area

Machine learning for estimation of building energy consumption and performance:a review

Ever growing population and progressive municipal business demands for constructing new buildings are known as the foremost contributor to greenhouse gasses. Therefore, improvement of energy eciency of the building sector has become an essential target to reduce the amount of gas emission as well as fossil fuel consumption. One most eective approach to reducing CO2 emission and energy consumption with regards to new buildings is to consider energy eciency at a very early design stage. On the other hand, ecient energy management and smart refurbishments can enhance energy performance of the existing stock. All these solutions entail accurate energy prediction for optimal decision making. In recent years, articial intelligence (AI) in general and machine learning (ML) techniques in specic terms have been proposed for forecasting of building energy consumption and performance. This paperprovides a substantial review on the four main ML approaches including articial neural network, support vector machine, Gaussian-based regressions and clustering, which have commonly been applied in forecasting and improving building energy performance

From the Sum of Near-Zero Energy Buildings to the Whole of a Near-Zero Energy Housing Settlement: The Role of Communal Spaces in Performance-Driven Design

Almost a century ago Modernism challenged the structure of the city and reshaped its physical space in order to, amongst other things, accommodate new transportation infrastructure and road networks proclaiming the,nowadays much-debated ‘scientificated’ pursuit of efficiency for the city. This transformation has had a great impact on the way humans still design, move in, occupy and experience the city. Today major cities in Europe, such as Paris and London, are considering banning vehicles from their historic centers. In parallel, significant effort is currently underway internationally by designers, architects, and engineers to integrate innovative technologies and sophisticated solutions for energy production, management, and storage, as well as for efficient energy consumption, into the architecture of buildings. In general, this effort seeks for new technologies and design methods (e.g., DesignBuilder with EnergyPlus simulation engine; Rhicoceros3D with Grasshopper plugin and Ecotect, Radiance and EnergyPlus tools) that would enable a holistic approach to the spatial design of Near-Zero Energy buildings, so that their ecological benefits are an added value to the architectural design and a building’s visual, and material, impact on its surrounding space. The paper inquires how the integration of such technological infrastructure and performance-orientated interfaces changes yet again the structure and form of cities, and to what extent it safeguards social rights and enables equal access to common resources. Drawing from preliminary results and initial considerations of ongoing research that involve the construction of four innovative NZE settlements across Europe, in the context of the EU-funded ZERO-PLUS project, this paper discusses the integration of novel infrastructure in communal spaces of these settlements. In doing so, it contributes to the debate about smart communities and their role in the sustainable management of housing developments and settlements that are designed and developed with the concept of smart territories

Nearly Zero Energy Mediterranean Schools as a Mitigation Potential to Climate Change

Climate change is a challenge for the construction sector. Buildings are responsible for great proportions of energy consumption and greenhouse gas emissions. EU energy policy encourages member states to start converting building stock into nearly Zero Energy Buildings (nZEB) and adopting exemplary actions. ZEMedS project focuses on the issues related to the refurbishment of Mediterranean schools to nZEB. ZEMedS aims to provide a roadmap with numerical indicators for energy demand and the share of renewable energy sources. The project covers a complete renovation path, tackling strategies for the envelope, the systems and renewable energy applications as well as the energy management and users' behavior. Ten typical schools from Catalonia, Tuscany, Athens, Ancona, Montpellier, have been analyzed in terms of the energy efficiency and cost optimality so as to contribute to the ongoing development of a methodology on how to achieve energy efficient and cost optimal nearly zero energy schools while ensuring the Indoor Environmental Quality aspects. A number of measures dealing with the building envelope and energy systems have been examined through energy auditing and simulations tools. The results ease the understanding of efficient design on the rising cost of energy, paving the way to zero energy consumption buildings

High-resolution spectral mapping of urban thermal properties with Unmanned Aerial Vehicles

The integration of microclimatic information and physical properties of the materials into urban design is essential for adequately addressing the challenges related to climate change and to adaptation of urban environment to new climatic loads. Especially, the thermal and optical properties of materials used in the urban fabric play a fundamental role in determining the microclimate and building's energy balance. The present research approach aims at analyzing the thermal characteristics of the materials and the surface temperature distribution using airborne multispectral imaging sensors mounted on Unmanned Aerial Vehicle (UAV). Aerial surveys and in-situ measurements have been carried out in April 2016 at the Municipality of Ymittos in Athens (Greece). The applied multi-sensory survey included high resolution imaging of the materials in the visible and near infrared (VIS/NIR) wavelength region and IR part of the spectrum. The images have been analysed to form maps of surface temperature distribution and of material properties. The derived thermal maps show the changes in surface temperatures of the urban materials during a diurnal heating cycle. In addition, ground measurements of VIS/NIR reflection and albedo from the survey area were obtained and an albedo map and a map of apparent thermal inertia were derived. Thermal scanning of the asphalt in the area, allowed the estimation of the state of decay due to weathering and traffic. The combined maps of surface temperature, albedo and apparent thermal inertia give new perspectives of the urban features and enhance the classification of fine urban material and the energy balance models. © 2017 Elsevier Lt

Using principal component and cluster analysis in the heating evaluation of the school building sector

In the field of energy savings in buildings, the interest towards the school sector is deeply motivated: schools have standard energy demands and high levels of environmental comforts should be guaranteed. The University of Athens in collaboration with the School Authority of Greece undertook a complete program on energy classification and environmental quality of school buildings. Data on energy consumptions were gathered and analysed with the participation of 1100 schools from all the prefectures of Greece. The data have been provided by the school authority of the country (OSK), in collaboration with the management of each school building. With regards to the size of the building and the external climate variability (HDD-method) energy normalization techniques have been applied in order to homogenize the data set. An energy classification tool has been created through clustering techniques, using the collected data regarding the heating energy consumption and as a result five energy classes have been defined. To evaluate the potential energy conservation for each class, the typical characteristics of school buildings belonging to an energy class have to be identified. A new methodology based on the use of the principal components analysis (PCA) has been developed. The method allows to define in an accurate way the typical building of each energy class and thus to perform analysis on the potential energy savings for the specific group of school buildings. By reducing the dimensionality of the problem, a bi-dimensional graphic in the first two PCs coordinate system promotes the understanding of the correlation between the examined variables, as well as the determination of sub-groups of school buildings with similar characteristics. The typical school of seven variables sample is defined as the closest to the medians in the principal components' coordinate system. © 2009 Elsevier Ltd. All rights reserved

Using principal component and cluster analysis in the heating evaluation of the school building sector

In the field of energy savings in buildings, the interest towards the school sector is deeply motivated: schools have standard energy demands and high levels of environmental comforts should be guaranteed. The University of Athens in collaboration with the School Authority of Greece undertook a complete program on energy classification and environmental quality of school buildings. Data on energy consumptions were gathered and analysed with the participation of 1100 schools from all the prefectures of Greece. The data have been provided by the school authority of the country (OSK), in collaboration with the management of each school building. With regards to the size of the building and the external climate variability (HDD-method) energy normalization techniques have been applied in order to homogenize the data set. An energy classification tool has been created through clustering techniques, using the collected data regarding the heating energy consumption and as a result five energy classes have been defined. To evaluate the potential energy conservation for each class, the typical characteristics of school buildings belonging to an energy class have to be identified. A new methodology based on the use of the principal components analysis (PCA) has been developed. The method allows to define in an accurate way the typical building of each energy class and thus to perform analysis on the potential energy savings for the specific group of school buildings. By reducing the dimensionality of the problem, a bi-dimensional graphic in the first two PCs coordinate system promotes the understanding of the correlation between the examined variables, as well as the determination of sub-groups of school buildings with similar characteristics. The typical school of seven variables sample is defined as the closest to the medians in the principal components' coordinate system.Energy rating Cluster analysis Principal components analysis School buildings

Experimental testing of cool colored thin layer asphalt and estimation of its potential to improve the urban microclimate

Urban Heat Island refers to the temperature increase in urban areas compared to rural settings, exacerbating the energy consumption of buildings for cooling. The use of highly reflective materials in buildings and urban structures reduces the absorbed solar radiation and contributes to mitigate heat island. This paper presents the results of a study aiming to measure and analyze the solar spectral properties and the thermal performance of 5 color thin layer asphalt samples in comparison to a sample of conventional black asphalt. Computational fluid dynamics (CFD) simulation is used for evaluating the thermal and energy impact of applying the samples in outdoor spaces (roads). The spectrophotometric measurements showed that the colored thin layer asphalt samples are characterized by higher values of solar reflectance compared to the conventional asphalt, which is mainly due to their high near infrared solar reflectance. From the statistical analysis of the surface temperatures it was found that all the colored thin layer asphalt samples demonstrate lower surface temperatures compared to conventional asphalt. The maximum temperature difference recorded was for the off-white sample and was equal to 12 °C. The CFD simulation results show that surface and air temperatures are decreased when applying the color thin layer sample. © 2010 Elsevier Ltd