Single-family Residences Research Articles

Identifying temporal properties of building components and indoor environment for building performance assessment

Buildings are dynamic thermal systems that require energy to maintain a comfortable indoor environment. Knowing these dynamics allows for identifying relevant building characteristics for assessing building energy performance. However, conventional building simulation programs take daily or monthly mean values for performance assessment. These often aggregate the errors and uncertainties between the theoretical and the actual building performance while missing the temporal dynamics on a minute or hourly basis. The objective of this study is to uncover the temporal aspects of building properties using data obtained by a wireless sensor network (WSN).Our analysis focuses on the following seven variables that are relevant for assessing building performance and retrofit measures: indoor air temperature, window opening instances, CO2 concentration, supply temperature from the heating system, outdoor air temperature, heat flux through the wall and the window. Using a single-family residence as a case study, we identify the temporal dynamics of these variables using polar plots on a high-resolution, 5-minute interval dataset. Following this, we define a set of conditional rules to study ‘expected’ and ‘unexpected’ impact of the six variables on the indoor air temperature. We observe strong temporal dynamics for certain building components, resulting in a large time lag. The conditional rule analysis also allows identifying energy saving potentials and factors contributing to the performance gap. For example, we observe high indoor air temperatures and at times when no occupants are present. Finally, we discuss the benefits of this approach with respect to building retrofit and energy performance gap analysis.

Free cooling potential of air economizer in residential houses in Canada

An air-side economizer uses outside air to reduce building cooling system energy demand. In Canada, air economizers are widely applied in non-residential building cooling systems but are rarely implemented in residential single-family houses. This study investigates the free cooling potential of the outside air through a temperature controlled air-side economizer in a hypothetical single-family house for sixteen cities across Canada. A series of thermal models with different aspect and window-to-wall ratios are developed to simulate the hourly and annual building cooling demand for each simulation case. The impacts of climatic conditions and building geometry on the potential annual usable and maximum available free sensible cooling are investigated. Results show that the available free cooling potential ranges from 50% up to 325% of the building cooling needs due to the mild summer weather in most areas of Canada; however, a majority of available free cooling is not able to be utilized. Further studies focused on finding the solutions to maximize the outside air free cooling usage to minimize the building HVAC system cooling energy use is necessary.

Containers – uma nova alternativa para a construção civil. Estudo direcionado para projetos residenciais

With pollution negatively affecting the world today, we have been seeking techniques and methods that will do less harm to the environment and to future generations. The constructive container method appears as an option for those who look for a clean and dry work, a flexible architecture, the reuse of materials that would be discarded, the preservation of natural resources and the reduction of constructive stages. This way, the objective of this work is to study the constructive method with the container material, its main stages of construction and the elaboration of a project. The applied methodology consists of bibliographical and documentary research, photographic exhibition and project development. The concept of sustainable construction was approached by analyzing its influence in the national and world scenario, aiming to reinforce the importance and the environmental responsibility in the project of residential dwellings. Finally, the project resulted in the design of a single-family residence with container, in which the projected space proved to be a viable solution for the metropolitan area of João Pessoa and also a functional for the users.

Análise das vazões de projeto de água fria em uma residência unifamiliar

Diferente da norma vigente de água fria, ABNT NBR 5626 (1998), que aponta o uso de método empírico, o projeto de norma em elaboração recomenda o uso do método probabilístico, que permite a consideração de parâmetros como vazão e duração de uso de cada aparelho sanitário, tornando o cálculo mais preciso. Portanto, a comparação da diferença entre estes métodos se torna importante bem como compará-los com medições reais de vazões e perfis de consumo. Desta forma, realizou-se a comparação das vazões de projeto entre os dois métodos propostos no padrão brasileiro, além de métodos propostos pelo padrão europeu (EN 806-3, 2006) e o projeto de norma portuguesa substituindo o Decreto Regulamentar no. 23/95, de uma residência unifamiliar. Além disso, a partir das vazões instantâneas medidas in loco em uma residência unifamiliar, verificou-se a distribuição das vazões nos trechos do sistema de água fria. Foi possível observar que as vazões de projeto estão normalmente próximas as vazões dos aparelhos, que o método probabilístico apresentou vazões próximas as vazões medidas.

Hybrid thermal energy storage with phase change materials for solar domestic hot water applications: Direct versus indirect heat exchange systems

A numerical model is developed and validated to simulate the performance of sensible energy storage (water tank) and hybrid energy storage (water tank including phase change material “PCM” modules) integrated into solar domestic hot water (DHW) system. Two configurations with direct heat exchange and indirect heat exchange using immersed heat exchangers are explored. A novel comparison is presented between both systems based on the solar fraction, which denotes the solar thermal energy contribution to the load. The effect of the storage volume on the solar fraction of the system is studied during a typical spring day while providing the hot water demands for a single-family residence, assuming a dispersed daily draw profile. The numerical results showed the crucial role of thermal stratification induced in the storage system with direct heat exchange. The storage system with direct heat exchange operates with 18–23% larger solar fraction than that with immersed coil heat exchangers. Adding PCM modules in the water tank with 50% volume fraction can yield around 40% potential reduction in the storage volume. The melting temperature of the PCM must be carefully chosen to maximize the energy storage in the latent form, thus limit the large temperature fluctuations of the system.

A revised capacitance resistance model for large diameter shallow bore ground heat exchanger

Ground heat exchangers (GHE) for residential heat pumps have the advantage of rejecting (extracting) heat to a lower (higher) temperature sink (source) as compared with air source heat pumps. The thermal performance of shallow GHEs with larger diameter and of helical shape is modelled in this study using both a lumped parameter numerical model and a commercially available computational fluid dynamics (CFD) software. Measurements in a real test site single-family residence are also used for soil property calibration. The lumped parameter numerical model (Capacitance Resistance Model, CaRM) is validated against the CFD simulation results and improved in order to capture detailed heat transfer processes within the core of the GHE. As result, the new CaRM model is able to better simulate the thermal behaviour of the helical GHE without high computational resources of the CFD model. Detailed local and global temperatures predicted by the numerical models are presented and discussed. Results indicate that the new CaRM tool better matches the trend of the CFD model. The average root-mean-square deviation between the revised CaRM and CFD models are 0.29 °C for the average core temperature and 0.75 °C for the borewall temperature which is an improvement of 27% and 35% respectively, in comparison to the previous version of CaRM.

Sources and dynamics of semivolatile organic compounds in a single-family residence in northern California.

Semivolatile organic compounds (SVOCs) emitted from building materials, consumer products, and occupant activities alter the composition of air in residences where people spend most of their time. Exposures to specific SVOCs potentially pose risks to human health. However, little is known about the chemical complexity, total burden, and dynamic behavior of SVOCs in residential environments. Furthermore, little is known about the influence of human occupancy on the emissions and fates of SVOCs in residential air. Here, we present the first-ever hourly measurements of airborne SVOCs in a residence during normal occupancy. We employ state-of-the-art semivolatile thermal-desorption aerosol gas chromatography (SV-TAG). Indoor air is shown consistently to contain much higher levels of SVOCs than outdoors, in terms of both abundance and chemical complexity. Time-series data are characterized by temperature-dependent elevated background levels for a broad suite of chemicals, underlining the importance of continuous emissions from static indoor sources. Substantial increases in SVOC concentrations were associated with episodic occupant activities, especially cooking and cleaning. The number of occupants within the residence showed little influence on the total airborne SVOC concentration. Enhanced ventilation was effective in reducing SVOCs in indoor air, but only temporarily; SVOCs recovered to previous levels within hours.

Étude de la performance du milieu filtrant constitué d’une couche de chènevotte sur une couche de grignons d'olives dans le traitement des eaux usées domestiques : du pilote à l’échelle industrielle

Deux matériaux, sous-produits agro-industriels, ont été étudiés en biofiltration à l'échelle pilote : la chènevotte en tant que « couche active », sur des grignons d'olives en tant que « couche de support ». L'objectif était d'étudier la capacité de ces deux matériaux travaillant ensemble comme un seul milieu filtrant poreux. L'impact de la hauteur de la couche active sur la performance du biofiltre a été étudié expérimentalement grâce à deux biofiltres, un premier présentant une répartition des matériaux en deux hauteurs égales, l’autre avec 80 % de couche active sur 20 % de hauteur de couche support. Les deux pilotes ont été alimentés à raison de 75 L·j‑1·EH‑1 (EH : équivalent-habitant) avec des eaux usées domestiques synthétiques. Les résultats ont montré une réduction de la demande biochimique en oxygène en cinq jours (DBO5) et des matières en suspension (MES) de plus de 90 % après dix semaines de fonctionnement. Cette performance s'est maintenue après plus de 30 semaines de fonctionnement continu. Par ailleurs, six prototypes de biofiltres ont été installés pour traiter les eaux usées domestiques de résidences unifamiliales dans des conditions réelles. Les objectifs de cette étude sont de caractériser l'efficacité du traitement de ces prototypes sur plusieurs années dans des conditions réelles, de déterminer l'entretien requis par une telle technologie et d'étudier l'influence de paramètres tels que la hauteur du biofiltre, l'aération et le nombre d'habitants. L'efficacité de traitement à long terme de l'un des biofiltres, qui fonctionne depuis près de quatre ans, est remarquable. Les pourcentages moyens de réduction de la demande chimique en oxygène (DCO), de la DBO5 et de MES sont respectivement de plus de 83 %, 97 % et 96 %, laissant espérer des résultats prometteurs pour les cinq autres.

LIFE CYCLE COST ANALYSIS OF ENERGY EFFICIENT SINGLE FAMILY RESIDENCE

Residential and commercial buildings account for more than half of the electricity consumption in the United States. There are numerous practical solutions to make buildings more energy efficient and sustainable. Although it is well-established that green buildings are socially, environmentally, and economically beneficial, there is still a lack of green buildings in the residential sector. The installation and upfront costs for these houses are very high. This research aims to facilitate a broader understanding of the cost benefits of energy efficient and sustainable residences. The Life cycle cost analysis (LCCA) approach and energy simulation tools have been utilized and integrated for assessing the traditional single-family residence in the United States. A comparative study has been carried out including passive and net-zero energy through energy simulation software. This analysis will benefit academic researchers and industry practitioners to analyze and evaluate challenges and opportunities in energy efficient and sustainable residences.

Probabilistic depth–damage curves for assessment of flood-induced building losses

The most common and internationally accepted method of assessing building damage due to flooding is through the application of a depth–damage curve (DDC). A DDC relates the percent damage or estimated economic loss to a buildings’ structural integrity and/or contents directly to a given water level (depth). The DDC generally represents an average structure within a given building category, e.g. one-storey single-family residence. Given the great variability across any given structural category, the variation in building materials, construction quality across communities and the singular focus on depth for estimation of losses, it is important to communicate the uncertainty and potential variability of the expected losses in any assessment. In this paper, probabilistic depth–damage curves (PDDCs) are developed based on synthetically derived DDCs from communities in southern Ontario. The generated PDDCs are based on assumed loss thresholds for minor and major loss levels, as spent in Canadian dollars. The economic loss estimates obtained in this way and their likelihood of being exceeded at any given flood depth express more transparently the potential building losses. An applied example of this method is included for both aggregate and building-by-building loss estimation.

Life cycle assessment of a typical European single-family residence and its flood related repairs

Floods are a constant threat to ecosystems, humans, infrastructure and assets. The combination of increased urbanization and rising sea levels makes it a concern of increasing societal importance. This study offers a new perspective on environmental impact assessment of flood related repairs related to a single-family residence using life cycle assessment. A typical European house built in the 2010's is modelled in the life cycle assessment framework with focus on items damaged by a flood. Flood damage is assessed on the detail level of the house's different components using flood depth as the indicator of damage level. A life cycle inventory is built individually for each considered item group affected by flooding. The influence of flood depths and house ages are studied. The results show that the main impacts of flood related repairs come from the replacement of the wooden flooring, the water heater and furniture. Overall, flood related repairs add between 3.5 and 17.8% of environmental impacts to the life cycle of the house depending on house age and flood depth; deeper water and bad timing in relation to maintenance cycles causing more impacts. Moreover, a very high positive correlation between environmental and economic impact is found in most impact categories.

Economic analysis and risk-based assessment of the financial losses of domestic rainwater harvesting systems

The considerable potential for rainwater harvesting (RWH) opens the door for the study of economic viability and risk indicators in this kind of system. The aim of this paper was to present economic and risk analyses of three RWH systems intended for water supply to single-family residences. The systems were analyzed based on water demand, degree of treatment and distribution arrangement. Economic, sensitivity and risk analyses were performed. The system with the basic treatment of rainwater and distribution by pressure (BX Pressure) was the most economically viable. The Net Present Value and the Intern Return Rate of the BX Pressure system was 480.36 USD and 6.85%, respectively. In the sensitivity analysis, both basic treatment systems were viable at any considered discount rate (0.00%–10.00%) and at a water price ranging from 1.58 USD to 2.72 USD for BX Pressure. In the risk analysis, BX Pressure was also the most viable system, presenting a risk probability of viability of 95.9% at current water prices. Water price, demand, lower discount rates and initial investment costs determined the greater economic viability and lower economic risk associated with domestic RWH systems.

Light rail transit and housing markets in Charlotte-Mecklenburg County, North Carolina: Announcement and operations effects using quasi-experimental methods

As planners and engineers in large cities around the United States continue to seek solutions to transportation-related problems such as congestion, greenhouse gas emissions, and safe and efficient access to goods and services, light rail transit (LRT) systems have become an increasingly popular option. While LRT has the potential to address these issues, it also has the potential to create negative externalities. This study examines the effects that LRT has had on the single-family residence housing market in Charlotte-Mecklenburg, North Carolina, in both the announcement and operations phases. Using spatially explicit quasi-experimental econometric models, we found that the announcement of the LRT led to increases in price per square feet for properties as distance to LRT station decreases while the price per square foot of properties decreases as distance to LRT station decreases after the system began operations. These results indicate that while land speculation may have resulted from the announcement of the LRT system, homeowners living closest to the stations during operations may have viewed the LRT stations more as a nuisance than a benefit.

Predictive Analytic for Estimating Electric Consumption of Smart Grid Platform in Residential Single-Family Building using Support Vector Regression Approach

This present paper attempts to corroborate the theoretical expert knowledge model-based data with the data-driven method in order to optimize energy efficiency use by high fluctuate occupants’ behavior level in typical residential single-family building at tropical country (i.e. Indonesia). Existing data set gathered from field observation and finished computed with Building Performance Simulation (BPS) software tools. The methodology for data-driven knowledge is using supervised machine learning with support vector regression technique, hence the physical engineering data become training data for learning purpose. Predicting algorithm is done in sequential minimal optimization for regression task (SMOreg), a library for support vector machine integrated in WEKA software with using radial basis functions (RBF) as the kernel. Moreover, electric bills are included to forecast future economic value of using smart grid technology.

Environmental performance of hybrid rainwater-greywater systems in residential buildings

The objective of this paper is to present and to apply a method based on Life Cycle Analysis (LCA) which was used to assess the environmental performance of hybrid rainwater-greywater systems in residential buildings. The method was applied in a case study in single-family residences in southern Brazil. The environmental impacts of two scenarios were compared: a house with a decentralized hybrid rainwater-greywater system and the same house with a conventional centralized water system. SimaPro software was used for environmental impact analysis and ReCiPe was used as an assessment tool. The average potential for potable water savings through the implementation of the hybrid rainwater-greywater system was 41.9%, the potential for domestic sewage reduction was 40% and the total energy consumption reduction in comparison to the conventional system scenario was 36.1%. The most significant environmental impacts in the assessment of the life cycle were related to the operational phase. The energy savings in the operation phase is essential to minimize the impacts observed and to maximize the sustainability and potential benefits. The findings of this study indicate that the scenario with hybrid rainwater-greywater system represents the most environmentally favourable option in single-family residences. The method is easy to adapt to different regions and can support designers and decision makers aiming to improve the performance of existing and new hybrid rainwater-greywater systems. It may also contribute to the recommendation of potential environmental mitigation measures and to the development of specific public policies to encourage the residential use of alternative water sources.

Analysis of building plumbing system flushing practices and communications.

Drinking water distribution system contamination incidents can prompt public agencies and drinking water utilities to issue do-not-drink and do-not-use advisories. After the contaminant is cleared from distribution mains, consumers are often directed to flush their plumbing. However, little validated guidance and few evaluated communications strategies are available on using flushing to decontaminate building water systems. Additionally, limited data support the effectiveness of current practices and recommendations. In this study, expert elicitation was used to assess existing flushing guidance and develop validated flushing guidance and communications for single-family residences. The resulting guidance recommends progressively opening all cold-water taps from the closest to point of entry to the furthest and allowing the water to run for at least 20 minutes. Hot-water taps should be opened progressively and run for at least 75 minutes. The guidance language and format conformed to grade-level and readability scores within recommended health communication ranges. The readability of eight other flushing guidance documents was also evaluated for contamination incidents from 2008-2015. Seven were written at a 10th-12th grade level, above the 6th-7th grade level recommended for health communications.

Statistical Analysis of Window Impacts on Cooling and Heating Energy Use in Single Family Residence Based on Climate Regions in U.S.A.

Purpose : Window area, location, and selection of glazing are a very important factor in reducing cooling and heating energy use of a building. The primary goal of this research is to investigate the effects of window design variables on annual cooling and heating energy use in a single residence based on climate regions in the United States using statistical analysis. Method : The methodologies used in this paper are building energy simulations, descriptive statistics, t-test, Latin Hypercube Sampling, and sensitivity analysis. Two groups of window variables are defined and simulated to explore the difference of the simulation results using Latin Hypercube Sampling and t-test. Then, the enter method as a regression model is used to investigate which group of data better predicted annual cooling and heating energy use. Lastly, Standard Regression Coefficients (SRCs) sensitivity indicator is used to determine if the influence of window parameters on cooling and heating energy use varies by different climate zone. Results : T-test results show that the differences in simulation results between the two groups are not statistically significant. That means that simulations using less number of variables (Group B) can have similar accuracy than simulation with higher number of window variables (Group A). As a result of the regression models, average adjusted R2 is 0.886 for Group A and 0.933 for Group B. Therefore, the regression model using Group B is selected to determine the effect of each variable on energy use. According to SRCs from regression, the most sensitive design parameters for cooling energy use are SHGC, west and south facing windows, while U-value, north and west facing windows are the most sensitive window parameters for heating energy use.

RA V9 N1, Mensaje del Editor en Jefe (Enero - Abril 2019)

Revista Latinoamericana de Control de Calidad, Patologia y Recuperacion de la Construccion http://www.revistaalconpat.org Es motivo de satisfaccion y alegria para el equipo de la Revista ALCONPAT ver publicado el primer numero de nuestro segundo ano al aire. El objetivo de la Revista ALCONPAT (RA) es la publicacion de casos de estudio relacionados con los temas de nuestra asociacion, o sea control de calidad, patologia y recuperacion de las construcciones motivando desde luego la presentacion de investigaciones basicas o aplicadas que pudiesen tener aplicacion con los casos de estudio. En este V2N1, iniciamos con nuestro articulo especial invitado, procedente de Portugal , donde Fernando Branco presenta una nueva filosofia para proyectar mas de 100 anos de vida de servicio en puentes. Fernando discute con propiedad la aplicacion de esta metodologia por primera vez en el Puente Vasco de Gama que fue proyectado para durar 120 anos. Fernando discute con claridad la fase de proyecto, de construccion y de gestion durante la vida de servicio. Entre los retos que nos presenta la industria de la construccion y la vida de servicio de las estructuras se encuentra desde luego la habilidad de producir cambios de uso para darle valor o extender la vida de una estructura. Este es el caso de un antiguo hotel transformado en banco que Alfredo Payer y sus colegas de Argentina describen con detalle desde la modelizacion numerica y analisis estructural de la estructura antigua y la refuncionalizada hasta el mismo procedimiento de construccion. Sin duda una exitosa rehabilitacion. En muchas ocasiones nos enfrentamos a verdaderos retos de inspeccion y restauracion que por sus caracteristicas pueden ser experiencias unicas. Muchas de estas no serian posibles sin un conocimiento adecuado del concreto y sus propiedades. Por ello, en este numero se abordan temas relacionados con el control de calidad que coadyuvan al buen entendimiento de la tecnologia del concreto y del capital humano. En el tercer articulo, Romel Solis y colegas de Mexico , presentan un caso como el que podria ocurrir en un clima calido, donde analizan la maxima resistencia de diseno que podria obtenerse con agregados triturados de alta absorcion. Mediante un procedimiento riguroso encuentran que 500 kg/cm2 es el valor maximo a obtener. Como nota curiosa, en sitios donde es comun el uso de agregados triturados de piedra caliza y el clima calido en Mexico se tenia la creencia de no poder alcanzar resistencias mecanicas mayores a 300 kg/cm2, tema que desde luego desmitifica el trabajo de Solis y sus colegas. En el cuarto articulo, Edith Cordova presenta un caso de El Salvador donde se logra documentar como el entrenamiento y supervision son clave para que el capital humano se convierta en un factor determinante en la calidad de las obras. Particularmente llama la atencion el uso de herramientas educativas y tecnologicas que se utilizan en este caso para llegar a su objetivo. El quinto articulo de RAV2N1 procede de Espana y en el Vicente Alegre y colegas muestran en forma por demas didactica el caso del colapso de la cubierta metalica de un polideportivo en donde ocurrieron problemas patologicos singulares pero que ya se habian presentado en otras obras. El sexto y ultimo articulo de esta edicion procede de Brasil , donde Santor y colegas presentan la influencia de los materiales de proteccion en la resistividad del concreto Cada numero de RA busca balancear la participacion de temas afines al objeto social de la ALCONPAT, por lo que la ingenieria estructural, el control de calidad, la inspeccion, diagnostico y reparacion se dan cita en cada numero desde los diferentes paises que conforman nuestra sociedad. Por el Consejo Editorial Pedro Castro Borges Editor en Jefe

The value of residential energy efficiency in interior Alaska: A hedonic pricing analysis

Residents of Interior Alaska are faced with a cold climate and relatively high energy prices, which results in high home energy expenditures. Increasing the energy efficiency of the housing stock can help reduce household energy expenditures. Following a spike in oil prices in 2008, legislation was passed, which created the Home Energy Rebate Program. Homeowners participating in the program were eligible to receive up to a $10,000 rebate for preapproved home energy efficiency improvements. This paper examines the effect of the Home Energy Rebate program on the selling prices of single-family residences in the Fairbanks North Star Borough from 2008 through 2015 using a hedonic pricing analysis. The results show that homes that completed the Home Energy Rebate program in the Fairbanks North Star Borough sell for a 15.1–16.5% price premium over similar homes that did not complete the program, which indicates that investments in residential energy efficiency are compensated. This is the first study to examine the impact of energy efficiency on house prices in a market with a subarctic climate.

Assessing overall building energy performance of a large population of residential single-family homes using limited field data

Building energy simulation plays a significant role in building design and retrofit. Most applications deal with individual buildings which allow for the specification of detailed model inputs. However, building energy simulation can be a powerful tool for assessing energy performance even when comprehensive building characteristics are unavailable. In this study, limited field data were collected on randomly selected new homes in eight US states with a goal of evaluating energy code compliance and energy savings potential. The limited data do not allow the derivation of comprehensive model inputs for each individual home sampled, let alone for the entire unknown residential construction stock. Therefore, we used prototype buildings to construct a large number of models and utilized bootstrap sampling to draw inputs from the limited data. This research demonstrates that overall energy performance of a large population of new homes can be assessed by the novel framework, given limited data.