bluuebunny/crossref_metadata_2025 huggingface dataset:
Divergence-free finite-difference method for 2D ideal MHD
Authors: Avdeeva E.N. , Lukin V.V.
Published: November 2019

The divergence-free finite-difference scheme for 2d ideal MHD using triangular unstructured staggered grids is described. In this approach the density, pressure and velocity fields are attributed to grid cells and magnetic field is defined by its normal components in cells edges. The HLLD approximate Riemann solver is used to compute the numerical flux of gas-dynamics variables at edges. It also provides the electrical field values used to compute the magnetic field. The magnetic field is interpolated into the cells using Raviart — Thomas basis functions. The algorythm is implemented in parallel numerical code. The method is tested on several well-known two-dimensional MHD problems.
A multi-scale and GIS-based investigation of climate change effects on urban climate and building energy demand for the city of Stuttgart
Authors: Ali-Toudert Fazia , Ji Limei
Published: November 2019

This paper presents a multi-scale and GIS-based investigation approach whose goal is to quantify the consequences of a climate change scenario (2041-2050) on the energy demand of buildings by comparison to a past scenario (1991-2000) applied to the city of Stuttgart. Energy simulations are made at building scale while taking into account the surrounding urban microclimates. The investigation method combines 1) numerical modelling using TEB and TRNSYS, 2) design of experiments (DOE) statistical analysis for data pre- and post-processing, and 3) GIS techniques. The outcome of the study is the heating and cooling energy demands summed up at city block level and displayed in 2D GIS maps. The results reveal that i) warmer urban microclimates occur, ii) with less heating and more cooling of buildings required if future versus past reference climate data are used. Spatial differences in the results within the city are found depending on the geometrical and thermal characteristics of the individual city blocks and buildings.
Coupled numerical simulations of cooling potential due to evaporation in a street canyon and an urban public square
Authors: Kubilay Aytaç , Derome Dominique , Carmeliet Jan
Published: November 2019

The extent and duration of evaporative cooling, as a countermeasure to the urban heat island effect, depend on factors such as moisture availability and material liquid capacity and permeability. The present study investigates the evaporative-cooling potential of conventional urban materials and green surfaces using two case studies: an isolated street canyon and a historical public square in the city of Zurich with a particular focus on pedestrian thermal comfort. The numerical model couples computational fluid dynamics (CFD) simulations of wind flow with the heat and moisture transport (HAM) in urban materials in order to resolve storage and transport in urban settings. This way, we aim to provide a framework for the development of sustainable and resilient solutions for local heat islands.
Tertiary building stock modeling: Area determination by fusion of different datasets
Authors: Tam Nguyen Huu , Decellas Fabrice , Duplessis Bruno , Rivière Philippe , Marchio Dominique
Published: November 2019

The building stock accounts for 43% of the total French final energy consumption in 2017. The French building stock mainly includes residential and tertiary buildings, which have very different consumption patterns. Today, building stock models are largely used in many countries for energy demand forecast and decision making. In this context, good knowledge of the building stock is essential for modeling. However, this type of model is lacking for the tertiary sector, as it is difficult to categorize buildings that have a wide variety of area and energy uses, different systems and complex dynamic trends. Existing stock models are mostly based on an aggregated representation of the total heated floor area of the building stock. Such a representation limits explicit studies of the factors affecting the energy demand and fails at taking into account heterogeneity. This paper exposes and discusses new methods aiming at modeling the tertiary building stock at the city scale in France. While mainly relying on open source public data, methods are designed to be applicable at any scale (from small cities to large region or even national scale).
The use of thermography to highlight the relationship between air and surface temperatures in urban scenes
Authors: Garcia-Nevado Elena , Roura Helena Coch , Beckers Benoit
Published: November 2019

The correlation between air and surface temperatures is recurrently used as a descriptor of the urban climate within built environments. The aim of this paper is to explore the possibilities of time-lapse thermography to visualize this relationship in time and space. To this end, thermograms are colorized using a relative-to-air temperature scale, instead of the usual absolute one. This approach was tested for two deep urban canyons belonging to cities with different climates. Relative-to-air thermography has two main advantages: it facilitates comparisons between the thermal responses of urban scenes under different climates and makes convective energy exchanges more comprehensive.
Urban densification and housing typology for climate change mitigation
Authors: Felkner Juliana , Brown Julien D. , Vazquez-Canteli Jose R. , Nagy Zoltan
Published: November 2019

This paper investigates different urban growth and densification scenarios and their energy performance under climate change conditions using urban energy simulation. We developed an abstract urban growth model based on the West Campus neighborhood in downtown Austin, Texas. Four different scenarios were applied to an abstract population growth model, which were then tested from the current year to 2100 under both climate change and control (TMY) conditions. Our results show that all urban growth models perform similarly in terms of operational energy but differ radically in terms of carrying capacity and embodied energy.
The impact of courtyard geometry on its mean radiant temperature
Authors: Al-Hafith Omar , Satish B.K. , Wilde Pieter De
Published: November 2019

For hot regions, studies have been advocating re-adopting the courtyard pattern for its thermal advantages. Aiming at developing thermally comfortable courtyards, studies have been exploring the impact of courtyards geometry on their shading and natural ventilation, which are the two environmental principles of courtyards. However, there is a lack of studies on the impact of manipulating courtyards geometry on the thermal sensation of occupants. This research investigates the impact of changing the courtyard geometry and the resulted shading on Mean Radiant Temperature (MRT) and Globe temperature (Tg). The latter represents the thermal perception of occupants and the former is the main effective factor on the thermal sensation of people in outdoor and semi-outdoor spaces. The research carried out simulation experiments to test 360 different courtyard configurations. The simulation experiments included using Envi-met and IES-VE simulation tools. The former was used to determine MRT and Tg, and the latter to determine shading levels. Baghdad was selected to represent an example of a hot city in which summer air temperature reaches around 50 °C. The results show that the difference in shading that results from changing the courtyard geometry can lead to a difference in MRT and Tg of up to 15°C.
Evaluation of thermal comfort in outdoor public space: Case of study: City of Annaba –Algeria-
Authors: Dafri Ibtissam , Alkama Djamel
Published: November 2019

Outdoor public spaces play an important role in the articulation of a city. The thermal comfort of these spaces has become a problem because of climate variations. Our work aims to study thermal comfort in outdoor public spaces in order to tackle the variability between microclimatic parameters which were taken from several field stations. Furthermore, it aims to identify the effect of the different factors and thermal conditions on both the microclimate and the external thermal comfort. A comparative study between three public spaces of the city of Annaba (course, square and garden) has been conducted. The method adopted for this research is based on the measurement of microclimatic parameters. The measurement took place during August 2016. It was performed by a thermal hygrometer to cover air temperature and relative humidity. Then, a thermal anemometer was used in order to estimate wind speed, every 2 hours from 06:00am until 08:00pm. The obtained results confirm the variability of the thermal environment in an urban environment and the impact of vegetation, urban morphology and water on outdoor thermal comfort.
Statistical modelling of the energy reference area based on the Swiss building stock
Authors: Schluck Thomas , Streicher Kai Nino , Mennel Stefan
Published: November 2019

The energy reference area ERA is one of the most important reference values for practitioners and scientists to quantify the energetic performance of a building. Its fast and easy prediction from generally available building characteristics is a regular need.

Here we present a comprehensive statistical model to predict the ERA based on a multiple regression approach and we motivate why the often chosen bivariate regression, i.e. simple regression should be disfavoured. Basis for the model development was a comprehensive data set of the Swiss buildings stock with about 30’000 buildings and 23 descriptive features. The final model only needs four building features to model the energy reference area. These features are the footprint, the living area, the number of floors and the buildings’ usages. The main key performance indicators during the model development were the coefficient of determination R
2 and the uncertainty given by the root-mean-square-error RMSE, which was determined on a test set (about 10% of the dataset). The here presented multiple model has an R
2 of 99.7% and gives low uncertainties for the predicted ERA ranging between 25% and 10% of the predicted value. Thus this work allows estimating the energy reference area and its level of uncertainty fast and easy. We are convinced that our efforts will support practitioners as well as scientists in their daily work by providing more accurate and less biased estimations of the ERA.
Applications of graph theory in district heat network analysis at national scale
Authors: Chambers Jonathan , Cozza Stefano , Patel Martin K.
Published: November 2019

District heat networks can make a significant contribution to decarbonising domestic heat supply and have been successfully applied in a number of countries. Traditionally, district heat networks have been analysed at the local or city district scale. Performing this analysis at national scale presents new methodological challenges. Efficient techniques are required to work with large datasets and enable rapid iteration of results. As district heating fundamentally involves networks, graph theory is highly relevant for providing well established analysis methods that can scale to very large datasets. Two applications of graph theory are presented for this work. The first presents a method for estimating minimum pipe lengths needed to connect buildings, from which demand densities may be derived. The second presents a graph-based clustering method for connecting distributed supplies and demand regions. These methods have been applied as Swiss national scale.
A cloud-based operation optimization of building energy systems using a hierarchical multi-agent control
Authors: Kümpel Alexander , Storek Thomas , Baranski Marc , Schumacher Markus , Müller Dirk
Published: November 2019

This work presents an agent-based control concept that we integrate into a cloud framework for controlling building energy systems. The agents are arranged in a hierarchical structure, where a coordinator agent sends optimized set point values to sub-agents. Each sub-agent controls a subsystem in order to reach the given set points and provides the coordinator agent with a cost function for the overall set point optimization. The multi-agent system and the building energy system exchange data via the cloud framework FIWARE. The components of the building energy system (e.g. boiler, air-handling unit) are connected to the cloud framework and send measurements (e.g. temperature values or volume flow) via a scalable IoT-Interface to the corresponding data object in the platform. The sub-agents of the agent control receive the measurements and send the calculated control action back to the corresponding components of the energy system. In a simulation study, we use the framework to control an air-handling unit. The aim of the agent control is to reach a given supply air temperature while reducing the total consumed energy. The implemented cloud-based control is capable of efficiently reaching the given temperature set points while communicating via the IoT interface.
Building energy flexibility: a sensitivity analysis and key performance indicator comparison
Authors: Johra Hicham , Marszal-Pomianowska Anna , Ellingsgaard John Ray , Liu Mingzhe
Published: November 2019

Buildings are a key active element of the future Smart Grids with large shares of renewable energy, as they can provide flexible energy usage to help balancing power production intermittence. There is currently no consensus yet on how to quantify building energy flexibility. The various KPIs found in literature can be classified into 4 main categories: load shifting ability, power adjustment, energy efficiency and cost efficiency. Most of them use a reference scenario. Moreover, the envelope performance appears to be the most important parameter with regards to all aspects of building energy flexibility when using indoor temperature set point modulation.
Economic optimization of micro-grid operations by dynamic programming with real energy forecast
Authors: Ramahatana Faly , David Mathieu
Published: November 2019

Optimal management of micro-grids requires anticipating the supply-demand unbalance. This work aims at developing a method to integrate real day-ahead deterministic forecasts of photovoltaic (PV) production and of system loads in the management of an ESS integrated inside a micro-grid. Dynamic Programming (DP) has been chosen to optimize the cost of the micro-grid operation. To test the developed method, a real educational Net Zero Energy Building equipped with a PV roof is considered. Compared to a management that does not take advantage of forecasts, the developed method allows decreasing the operating cost of the system.
Model-predictive control for testing energy flexible heat pump operation within a Hardware-in-the-Loop setting
Authors: Frison Lilli , Kleinstück Martin , Engelmann Peter
Published: November 2019

Model-predictive control is a smart control technique that can unlock the potential of the building’s thermal production leading to improvements in energy efficiency or energy flexibility, which is obtained by a demand responsive operation based on external grid signals. This work explains the set-up of a Hardware-in-the-Loop experiment to test an energy flexible heat pump controller under realistic conditions. The developed simple, low-cost model-predictive control algorithm can easily be integrated with a traditional heat pump controller.
The Cold Tube: Membrane assisted radiant cooling for condensation-free outdoor comfort in the tropics
Authors: Teitelbaum Eric , Chen Kian Wee , Meggers Forrest , Pantelic Jovan , Aviv Dorit , Rysanek Adam
Published: November 2019

Air conditioning demand is projected to increase rapidly over the next 50 years, particularly in already hot and humid climates. Radiant cooling can be an energy efficient strategy to mitigate comfort energy demand with high air temperatures, thereby reducing both sensible and latent loads in spaces. We have built an outdoor radiant cooling pavilion, the Cold Tube, which is able to produce a mean radiant temperature up to 10 °C below the air temperature in hot and humid Singapore. It avoids condensation and unwanted air cooling by separating cold surfaces from the outside air with a membrane transparent to the radiant cooling heat transfer. This strategy eliminated unwanted convective losses in the form of sensible (air conditioning) and latent (condensation) losses. Controlling the system to avoid condensation was a major feature of the research, and the results show that as cooling demand increases due to warmer air temperatures, the cooling capacity of the Cold Tube also increased to compensate, providing comfortable setpoints to all measured ambient conditions over the duration of the experiment. For ambient air conditions on site in Singapore of 31°C and 65 %RH, we were able to maintain a 22°C mean radiant temperature inside of the pavilion. The additional cooling increased heat flux from exposed human skin to 156 W m
−2 and was successful at avoiding condensation. While this study was conducted outdoors, this demonstration and evaluation will help inform subsequent applications of the technology, such as augmenting comfort in naturally ventilated indoor environments.
First solar hydrogen storage in a private building in western Switzerland : building energy analysis and schematic design
Authors: Couty Philippe
Published: November 2019

Self-sufficiency of buildings with carbon emission reduction can be obtained thanks to the introduction of Photovoltaics systems coupled with Hydrogen seasonal storage. To be self-sufficient over the year, the electricity converted to hydrogen by electrolysis during the sunny season can be re-used with the help of fuel cells during the winter season. This article is dealing with the dimensioning methodology of a solar PV hydrogen-electrochemical system for self-sufficient buildings. We introduce the case study of the first private building in western Switzerland that will be equipped with solar hydrogen storage. Calculation results of the dimensioning of the PV system with storage will be presented. The life cycle assessment and the calculations of the environmental indicators GWP and CED will be introduced.
SmarSolar : PV production forecast used by the Swiss team, winner of the U.S. Department of Energy Solar Decathlon competition 2017 Denver, Colorado
Authors: Couty Philippe , Arn Christophe
Published: November 2019

The article introduces the SmarSolar platform which merges customer management relations tools and Photovoltaic forecast services. We will present the modelling hypothesis as well as the validation of the model. The forecast service has been successfully used by the Swiss team in the Solar decathlon Competition US 2017 who won the competition. In a more general perspective, since all data and results are centralized in a database with cloud computing services, the platform can be used by installation owners to optimize their self-consumption as well as by electrical producers managing their park of PV installations and optimizing the grid load.
An uncertainty and sensitivity analysis of Power-to-Hydrogen as a seasonal storage option in a district multi-energy system
Authors: Petkov Ivalin , Gabrielli Paolo
Published: November 2019

Seasonal energy storage plays a key role in low-carbon multi-energy systems (MES) by storing renewable generation in times of excess supply in order to meet energy demands months in the future. Power-to-Hydrogen (PtH2) is being investigated as a promising long-term storage solution for integrated MES. In this preliminary work we investigate under which conditions does PtH2 become a seasonal storage option in district MES through an optimization framework including an uncertainty and sensitivity analysis to evaluate the effect of technological and contextual uncertainty on PtH2 execution. PtH2 becomes vital in low-carbon, renewable-heavy, MES for meeting high thermal demands in winter.
A multi-objective optimization model for the operation of decentralized multi-energy systems
Authors: Adihou Yolaine , Mabrouk Mohamed Tahar , Haurant Pierrick , Lacarrièere Bruno
Published: November 2019

A multi-energy system couples several carriers such as electricity and heat to meet mutual synergies, optimizing the global efficiency of the system.

In this study, a multi-objective optimization is developed to establish the optimal design of a
decentralized multi-energy system, by maximizing the renewable energy coverage rate and minimizing the operation costs at the same time. To retrace the typical demand profile that groups together the different uses of a neighbourhood, historical data are used in addition to simulation of buildings. On this basis, a set of energy production systems are modeled to form a multi-energy system providing energy to a neighbourhood in Nantes (France). An optimal sizing of the technologies is carried out using a genetic algorithm. Two objective functions are considered based on renewable energy coverage rate and operation/total cost. The study shows that renewable energy systems integration leads to higher total costs compared to a boiler only system, whereas when considering operation costs only, it is possible to reach a 12 % renewable energy system coverage rate and realize cost savings at the same time.
Characterization of heat-pump, PV and battery demonstrator technologies using a coherent energy assessment
Authors: Allan James , Georges Gil , Heer Philipp , Budiman Dylan , Croce Luca
Published: November 2019

Battery, PV and heat-pump technologies were characterized using a Coherent Energy Demonstrator Assessment (CEDA) approach. In all cases the calibrated simulation models closely matched the measured data; however it is not possible to conclusively say that models, based on a single demonstrator, represent all existing and future cases of a technology. A possible solution would require additional operators to characterize and report the performance of a given technology, in a standardized way, and the resulting data could then contribute to an evolving set of representative CEDA archetypes to be used in studies of energy systems.
Energy sharing through shared storage in net zero energy communities
Authors: Vindel Elvin , Berges Mario , Akinci Burcu
Published: November 2019

Growth in the adoption of distributed energy resources is shaping a new energy ecosystem posing a perceptible threat to the grid by relying on it as a virtually inexpensive storage mechanism. This growth is compounded by new policy objectives that require pursuing net zero energy (NZE) goals for new buildings. One emerging framework that attempts to remediate this problem is energy sharing in a community microgrid. In this framework, through complementary demand profiles and shared energy storage, buildings use energy resources more efficiently with the objective of reducing grid interactions. In this paper, we create a year-long discrete-time simulation model of 40 residential and non-residential buildings to measure the reduction in grid interactions through energy sharing and shared storage for the case of a NZE community. Our results show that, when sharing is enabled, a 9.5% reduction in grid interactions can be obtained with buildings that have energy storage. Additionally, a month-by-month exploration revealed that annual patterns in generation drastically impact the benefits from sharing energy. The reduction in grid utilization ranged from 20% during periods of high energy surplus (i.e. summer) to 5% during low energy generation (i.e. winter).
Development and dissemination of deep-energy retrofit strategies through a mandatory municipal building tune-up ordinance in Seattle, Washington, USA
Authors: Meek Christopher , Gustin Andrew , Ballinger Nicole
Published: November 2019

This paper describes initial implementation of a municipal-scale building-owner engagement and technical assistance process aimed at accelerating voluntary deep energy retrofits as part of a new mandatory building tune-up requirement. Leveraging building energy consumption disclosure data, a municipal ordinance mandating building tune-ups at five-year intervals, and a suite of freely-available energy simulation tools, the university-based research and deployment team seeks to develop a scalable pathway for creating custom technical and financial roadmaps for deep-energy retrofits that drive carbon-neutral operations in existing medium-sized buildings.
Impact of solar insulation film on the cooling load of an office building in Singapore - A simulation study
Authors: Pawar Priya , Boranian Aaron , Lang Werner
Published: November 2019

This study investigates the properties of a pre-existing high-performance Low-E Double Glazed Unit (DGU) commonly used for fenestration in buildings in Singapore through simulation. Lawrence Berkeley National Laboratory window series software Optics 6 and Window 7 were used to determine the thermal properties of the glazing systems. The window series software based calculations revealed that upon application of the film, Solar Heat Gain Coefficient (SHGC) and the Thermal Transmittance (U-Value) were reduced by 13% and 1%, respectively. Trimble SketchUp Pro was used to develop the geometry of the medium-rise office building, and the OpenStudio interface for EnergyPlus was used to simulate each scenario. Five studies were undertaken to holistically understand the impact of solar insulation film including the reduction in the cooling load and energy usage. The energy study consists of simulating two scenarios so that ACMV component capacities and flow rates are automatically calculated by EnergyPlus. These simulations quantified that after applying the window film, the cooling load reduction on a design day was 8%, and the annual cooling energy savings was approximately 9%. Higher cooling load reduction and cooling energy savings occurred for the shallow floor plan. The numerical calculations of Envelope Thermal Transfer Value (ETTV) suggest a comparative improvement of 14% with the application of a window film.
Optimization module for filtering and ranking alternative energy replacement systems, in an online ICT design tool for building retrofits
Authors: Elguezabal Peru , Arregi Beñat , Armijo Alberto , Schuetz Philipp , Gwerder Damian , Scoccia Rossano , Tsagkrasoulis Dimosthenis , Aprile Marcello
Published: November 2019

This paper describes the development of an innovative optimizer component as part of a calculation tool for evaluating and comparing a set of retrofitting options for domestic heating and cooling systems. At the initial stage of the process, a filtering sub-module has been developed to pre-process the information introduced by the user and generate a limited set of simulations, thus speeding up the calculation process. At a later stage, the optimizer collects and post-processes outputs from the simulation core before displaying them as a result. In this later stage, a series of performance indicators are calculated and an analytical hierarchical process (AHP) is performed to rank the results based on the user’s prioritization weighting for each key performance indicator. As the main outcome of this contribution, the benefits of implementing this optimizer are evaluated in increasing the efficiency of the rest of the components of the tool and, consequently, of the overall calculation process.
Portfolio energy analysis and condition assessment: case study of public schools of the Lugano municipality
Authors: Branca Giovanni , Curto Ivan , Tamborini Davide , Maltese Sebastiano , Corti Paolo , Soares Carlos Pereira
Published: November 2019

Buildings significantly contribute to the overall energy balance, so an accurate approach for condition assessment, energy performance benchmarking and retrofit scenario selection is necessary. The aim of this research is to analyse the energy performance and the overall condition of public buildings in the Ticino Canton; this paper focuses on 31 school buildings of the Lugano Municipality. The analysis has been conducted using a combination of tools (PETRA, BIM, GIS) and aims at defining retrofit scenarios and providing public managers with a precise picture of their portfolio. This portfolio investigation allows for an appropriate building operation and management strategy.
Investigation on energy performance of existing commercial buildings with heritage values by incorporating retrofit options
Authors: Chew Wong James Pow
Published: November 2019

The buildings sector accounts for 24% of Australia’s indirect Greenhouse Gas (GHG) emissions. Due to the life expectancy of existing building stock the greatest reduction in emissions before 2030 could be achieved through retrofits. Research in the past has shown that energy consumption in commercial buildings is complex and diverse due to the wide range of building fabrics and mechanical systems employed. Typically, the most effective energy saving strategies in commercial buildings have been in improving the heating, ventilation and air-conditioning (HVAC) design and efficiency, including improving the efficiency of chillers and heat pumps, and design strategies such as efficient mechanical ventilation systems, night purges, thermal mass and daylighting. This paper investigates and evaluates the energy performance of four commercial case study buildings with heritage values with various retrofit options in different climatic conditions in Australia. The paper explored the use of thermal and airflow modeling in assisting to understand the impacts of various retrofit options unto the energy efficiency of the case study buildings. The findings suggest different retrofit options that should be considered for achieving optimum energy efficiency impacts for existing buildings in Australia.
BIT – Building Impulse Toolkit: a novel digital toolkit for productive, healthy and resource efficient buildings
Authors: Luna-Navarro A. , Allen M. , Meizoso M. , Overend M.
Published: November 2019

This paper presents the “Building Impulse Toolkit” (BIT), a novel array of digital sensors and methodologies for the transient and holistic tracking of occupant response in the built environment. BIT aims to enable the dynamic monitoring of occupant comfort, productivity and well-being in order to inform responsive and predictive control strategies. Further, to assess user experience in order to facilitate the design and operation of future resource-efficient and occupant-centred buildings. This paper describes the preliminary results and limitations of this novel toolkit and, subsequently, discusses the future research and development required.
An agent-based model framework for understanding the decisions of households and exploring bottom-up effects on housing sustainability
Authors: Pagani Anna , Shinde Rhythima , Hellweg Stefanie , Binder Claudia R.
Published: November 2019

Housing plays a crucial role in the transition towards sustainability. Zero-energy or low-carbon housing solutions are key, but their success depends on their acceptance by the users. We propose a conceptual and an operational framework for understanding households’ residential choices as a base for an agent-based model, using the tenant as basic unit to populate it. We firstly conceptualise the decision-making process of tenants as a system. Secondly, we cluster the synthetic agents populating the model into typologies of dwellings and tenants. Thirdly, we display their actions in the action arena, and set-up the test runs. Lastly, we introduce the next steps to follow for the simulation of the bottom-up effects on housing sustainability.
Comparison of simulated energy consumption by smart and conventional lighting systems in a residential setting
Authors: Soheilian Moe , Moadab Nima Hafezparast , Fischl Geza , Aries Myriam B C
Published: November 2019

This paper investigated and compared how the energy consumption of a conventional and Smart Lighting System (SLS) in a simulated residential setting is affected by different households’ arrangements and occupancy pattern. An agent-based simulation model of a one-bedroom apartment in Sweden was chosen for comparison with different scenarios. The result shows that the number of residents within an apartment does not necessarily lead to higher energy consumption. Further findings indicate that, even though it has standby energy consumption, SLS is more energy efficient compared to the conventional lighting system. Additionally, energy consumption during weekends was considerably higher than during weekdays.
A low-cost stereo-fisheye camera sensor for daylighting and glare control
Authors: Kim Michael , Konstantzos Iason , Tzempelikos Athanasios
Published: November 2019

This study presents the development of a window-attached, low-cost fisheye-stereo camera sensor system for reliable daylighting controls in buildings. The stereovision sensor composed of two cameras can measure 3-D position and luminance of any exterior bright sources after photometric and geometric calibration. Also, by applying a neutral density sensor on one of the cameras and substituting the overflown pixels of the luminance map, a complete luminance map with a wide dynamic range can be retrieved. The new sensor exhibited promising results in validation of 3-D positioning and luminance acquisition, and can be used for real-time glare source detection, location and intensity measurements.
A framework outlining a daylight responsive model for smart buildings
Authors: Sait Unais , K V Gokul Lal , Kumar Tarun , Bhaumik Rahul , Bhalla Kriti
Published: November 2019

The intensity of daylight varies due to periodical changes in the sun’s position, changing cloud-cover over the region, and other weather-related phenomena. Thus, artificial lighting remains a major component of the overall energy consumed in smart buildings. This necessitates corrections for maintaining optimum lighting levels in these buildings, by enhancing the positioning of artificial lighting sources with respect to outdoor lighting conditions. In this paper, a methodological framework is proposed for developing a daylight responsive model to minimize energy consumption for artificial lighting. This could be achieved by optimizing the usage of natural lighting in the built-environment, with the aid of Geo-location and sun-path tracking in a simulated model using Unity software. This smart daylight responsive model integrated with Virtual Reality (VR) would aid in designing an efficient lighting system utilizing Building Information Modelling (BIM). Further, this framework would help architects, engineers, and other stakeholders to collaborate, and virtually visualize the lighting conditions in smart buildings. In conclusion, an energy-efficient model for lighting can optimize the energy usage pattern in smart buildings, effectively increasing the usage of natural lighting.
Simulation of indoor temperature and humidity conditions in the suburban and urban area over a hot summer
Authors: Zhou Xiaohai , Carmeliet Jan , Derome Dominique
Published: November 2019

Urban areas are already suffering from the heat island effect. In the context of climate change, there will be higher temperatures and longer, more severe, and more frequent heat waves. The balance of indoor air temperature and relative humidity is very important for health and comfort of the occupants, building energy consumption and durability of the building envelope. In this study, a numerical model that incorporates building envelopes, indoor environment, indoor moisture and heat generation is developed. This model is validated with an analytical solution and with the BESTEST cases. We apply the whole building simulation model to study indoor temperature and humidity conditions in urban and suburban areas in Zurich, Switzerland in the summer of 2018. Indoor air temperature and relative humidity will not be accurately simulated when moisture transport in the building envelopes is not considered. There is a large difference of indoor temperature in the urban and suburban area during heat wave. The effect of moisture transport in the building envelopes on indoor temperature and relative humidity is important. Moisture transport could sometimes have a large influence on indoor thermal conditions. There is a potential of using hygroscopic material to lower indoor air temperature during heat waves.
Energy consumption of high-performance buildings: Design vs. Reality
Authors: Cozza Stefano , Chambers Jonathan , Gambato Carlo , Branca Giovanni , Geissler Achim , Patel Martin K
Published: November 2019

Studying the performance of highly efficient buildings is crucial for future policy, for example to inform decision making about whether to pursue further thermal improvement of buildings (insulation) or to rather foster investments in renewable resources. For this purpose, reliable values of the energy demand of new and retrofitted buildings are needed. However, there is evidence of a significant Energy Performance Gap (EPG) in buildings, defined as the difference between measured and calculated energy consumption. The objective of this paper is therefore to quantify the EPG in high efficiency buildings in Switzerland. The EPG was studied for 56 residential buildings, including various construction standards (Minergie, Minergie-P, and Minergie-A) and building types (new and retrofitted). The Minergie indexes were used as theoretical consumption, thereby representing the total final energy consumption for all needs of the buildings. These values were compared to data based on measurements. For the buildings in the sample the analysis yields a negative EPG of -14% (i.e. the median building consumes slightly less than its standard), indicating that the most efficient buildings are more robust to the EPG. However, this finding could be partly a consequence of the small sample used and its characteristics.
Hygrothermal assessment of historic buildings’ external walls: preliminary findings from the RIBuild project for Switzerland
Authors: Giorgi Morgane , Favre Didier , Goulouti Kyriaki , Lasvaux Sébastien
Published: November 2019

To meet the national regulation on building energy needs while preserving the architectural heritage, the renovation of protected historic buildings implies to insulate internally their facades. However, it is a technically risky solution. This work is part of the European project RIBuild that develops guidelines to ensure moisture-safe solutions. For that purpose, historical buildings were monitored to confront the current state-of-the-art of hygrothermal simulations with in-situ measurements. To enforce these calculations, stones used in Swiss traditional construction were characterised, and materials’ modelling were investigated. The results of the study will be integrated into a probabilistic web-tool.
The future of modernist housing estates: the “Replace vs Refurbish” dilemma in the context of future urban densification
Authors: Tepavcevic Aleksandar
Published: November 2019

The aim of this paper is to present a part of the research developed inside the author’s dissertation topic which deals with the future of large modernist housing estates. The central question of the dissertation investigates which of the currently dominating tendencies - their replacement or refurbishment - result in lower energy consumption and provides more sustainable use of natural resources within the context of future urban densification. The presented workflow combines actions contained in the first step of the research methodology built around the abovementioned dilemma. It explores the solar energy harvesting potential of various urban forms and densification scenarios, proposed inside the main “refurbishment” and “replacement” approaches, including both retain and demolition options of the existing building stock located in the Nordweststadt housing estate in Frankfurt, Germany. All scenarios are tested against maximal density rate which secures enough operational energy from on-site renewable energy sources for the achievement of the zero energy building (ZEB) standard. The expected outcome of this paper gives an insight which of the proposed densification scenarios from both approaches generate the highest density rate in respect to the given boundary conditions, and compares the energy balance between the best performing scenarios in both approaches at the same density level.
Composite polymeric materials as an alternative to aluminium for improved energy performance of ventilated façade systems
Authors: Arregi Beñat , Elguezabal Peru , Álvarez Izaskun
Published: November 2019

Ventilated façade systems have become an interesting solution in the field of energy efficiency for buildings thanks to their associated improvement in thermal insulation properties. However, differences exist between real and theoretical thermal performance, resulting in an increase of actual energy consumption above predicted values. Part of this mismatch can be attributed to thermal bridges both at support elements and at construction junctions, which are usually overlooked by simplified calculations. The present study assesses the potential for substituting metallic elements with polymeric composite materials for two key elements of ventilated façades: the support subframe of the external cladding and the external window reveals. Thermal, structural and durability properties are specifically assessed. Results show that overall heating energy savings between 7 and 13% can be obtained through the use of pultruded composite profiles at support brackets and window reveals instead of aluminium components. Such solutions are feasible from a mechanical and durability point of view, and the extra costs are offset in a short period through the reduction in heating expenses.
Management of urban solid waste in the two first decades of the XXI century in the city of San José de Cúcuta, Colombia
Authors: Sayago-Ortega J C , Carrillo-Soto G A , Rojas-Suárez J P
Published: November 2019

The research developed in this study is exploratory, descriptive and the quantitative method, it characterizes the urban solid waste of the ten communes of the city of San José de Cúcuta and compares the results obtained with those of a similar investigation carried out 20 years. This comparison concludes that there have been significant changes in solid waste generated in the city, increasing food waste, cardboard, plastic, glass and cans and decreasing garden waste, paper and metals. In addition, surveys were conducted indicating that about one third of the population makes waste separation evidencing the existence of the recycling culture.
Determination of expandability clay from San José de Cúcuta metropolitan area, by adding different percentages of sewage sludge
Authors: Cáceres J R , Rojas J P , Sánchez J
Published: November 2019

This article shows the research carried out on clay from the San José de Cúcuta metropolitan area, Colombia, to which was added several percentages of a wastewater sludge, which is called as a technological nutrient. The objective of the study is to find out with what percentage of technological nutrient the capacity of expansion of the granules is maximized. The methodology that was followed consists of four phases; preparation of raw materials; pelletizing of raw materials in granules of 5 to 10 millimeters; application of heat treatment in a rotary kiln at the pilot plant level; and application of descriptive statistics for analysis of results. It was determined that the mixture with a 20% of technological nutrient, produces the highest volumetric expansion ratio, with 1.56 times its initial size, while, when adding 30% of the nutrient the same expansion occurs when adding an 10% nutrient, which is 1.07 times the initial size of the particle.
Orthotic prototype for upper limb printed in 3D: A efficient solution
Authors: Agudelo-Ardila C P , Prada-Botía G C , Rodrigues G P H
Published: November 2019

Traditionally a limb that has suffered a fracture, rupture or dislocation is immobilized with plaster, a procedure that generates discomfort in the patient to take a shower, besides producing excessive itching and sweating, stimulating the growth of the bacteria and leading to an odorous form, unhygienic and difficult to keep clean of treatment. On the other hand, if the plaster remains for a long period, it can cause injuries in joints and ligaments. This project describes a methodology of manufacturing a prototype of orthosis for upper limb printed in 3D, through additive manufacturing and reverse engineering, technology that is presented as an excellent alternative to solve the problems of traditional plaster molds. The model of the orthosis is obtained through the Meshmixer software and the structural viability of the design is studied using methods of finite element analysis and biomimetics, to guarantee the best possible mechanical properties. The realization of this work provides a custom-made prototype orthosis, a more comfortable, hygienic and aesthetically pleasing solution, which in turn allows the reduction of the time of use of the plaster molds.
Quality of aggregates for the preparation of asphalt mixtures from 4 processing companies in San José de Cúcuta, Colombia
Authors: Hurtado-Figueroa O , Colmenares-Bernal CE , Cárdenas-Gutiérrez JA
Published: November 2019

Four asphalt mix processing companies were visited: Transivic S.A.S, Maquinteligente S.A.S, Copavicol S.A.S and Grupo Colpao S.A.S, companies located in the city of San José de Cúcuta, Colombia. Samples were taken of the stone material marketed by each of the companies for the preparation of asphalt mixtures, especially hot dense mixture-19. The stone aggregates taken from the processing companies were submitted to the analyses described by the “Instituto Nacional de Vías” 2013 for approval in the preparation of asphalt mixtures, regulations that apply in Colombia. The results obtained in the tests carried out with natural stone material were tabulated and analyzed comparatively in order to determine which of them is the most suitable for use in the preparation of the hot dense mixture-19. This provided interesting data on the quality of this material for the preparation of asphalt mixtures in each of the 4 processing companies. With the analysis of the results carried out, it was concluded that only 1 of the 4 material processing companies have high quality indexes. Research conclusion that provides information of interest to civil engineering contractors specialized in the construction of asphalt pavements, who will make important decisions regarding the acquisition of the ideal material for their next projects, thus constructing more durable works, a characteristic that contributes considerably to the economy of the project. In addition, a positive social and environmental impact is generated with the minimization of maintenance and repairs of the work carried out, an activity that leads to a reduction in the industrialized processes that generate polluting waste with respect to the preparation of construction materials for this type of projects.
The role of green it in the non-functional software development requirements: Perspectives for functional design
Authors: Velásquez T , Messino A , Navarro H E , Ovalle A A
Published: November 2019

Many of the research carried out on green information technology or green technologies has focused on reducing the environmental effect, on the design, development and use of increasingly eco-efficient electronic devices, in terms of the machine, that is, the hardware; but this trend has changed in recent years, due to the concern to cover all fronts in which green information technology is part; what has allowed to generate studies and investigations in another aspect, as it is the software. Some authors have addressed the issue, however, models, descriptions or implementations in the area of software are still in short supply, whose main rationale is eco-efficiency, that is, environmental strategies to reduce the impact of a product or service by increasing the efficiency of resource utilization. The research emphasizes the formulation of a guide based on the principles promulgated in green information technology as a non-functional requirement in the analysis and design of software and incorporating this guide in the software engineering projects of the systems engineering program of the Universidad Francisco de Paula Santander, Seccional Ocaña, through the content of the green information technology elective course and as an academic unit of the software engineering course.