Window Orientation Research Articles

Cross comparison of empirical and simulated models for calculating residential electricity consumption

The U.S. Energy Information Administration's Residential Energy Consumption Survey (RECS) provides electricity end-use estimates derived from disaggregating total household consumption. However, the accuracy of the EIA's disaggregation method is unclear, thus potentially producing erroneous end-use estimates and affecting respective decision support. In order to test the EIA's disaggregation methods, we perform parallel empirical analysis of residential cooling demands on two household samples located in Texas: an estimated sample (RECS) and a sample where air conditioning branch circuits are directly metered. Results indicate statistically significant differences between data sources, with the RECS sample possibly underestimating cooling demands. Results further indicate that models developed using observed end-use consumption are more robust, demonstrating statistically significant predictors that do not significantly correlate with end-use estimates from the RECS sample. We find that accounting for seasonality increases predicted R2 values and reduces overestimation of statistical significance. Finally, the observed model indicates that window area and orientation are statistically significant predictors of cooling loads, which are parameters not surveyed in RECS. We then provide policy recommendations to improve end-use estimates, including integrating select utility-funded audit data into disaggregation methods.

Study on Ventilation Rates at University Dormitories in Winter

The university dormitory is a typical indoor environment. The ventilation rate is a significant factor for indoor air quality in the dormitory. The objectives of this study are to determine whether the ventilation rate in the dormitory in winter meet indoor air quality standard or not, and understand the effect of window orientation, storey and time on the ventilation rate. In this study, the university student act as CO2 emission source; indoor and outdoor CO2 concentrations were measured in the same time. During the sampling, the size of the dormitory, number of people and their activity were recorded. The ventilation rates of dormitories in university were calculated by the least square method according to indoor and outdoor CO2 concentrations. The results showed that the door or window is open can increase the ventilation rates, but the effect is limited; totally speaking, the ventilation is very inadequate in dormitories in winter, and it is difficult to meet indoor air quality standard. The window orientation, storey and day and night can affect the ventilation rate. We should study it further to improve the ventilation of dormitories.

Impact Analysis of Window-Wall Ratio on Heating and Cooling Energy Consumption of Residential Buildings in Hot Summer and Cold Winter Zone in China

In order to assess the optimal window-wall ratio and the proper glazing type in different air conditioning system operation modes of residential buildings for each orientation in three typical cities in hot summer and cold winter zone: Chongqing, Shanghai, and Wuhan simulation models were built and analyzed using Designer’s Simulation Toolkit (DeST). The study analyzed the variation of annual heating energy demand, annual cooling energy demand, and the annual total energy consumption in different conditions, including different orientations, patterns of utilization of air conditioning system, window-wall ratio, and types of windows. The results show that the total energy consumption increased when the window-wall ratio is also increased. It appears more obvious when the window orientation is east or west. Furthermore, in terms of energy efficiency, low-emissivity (Low-E) glass performs better than hollow glass. From this study, it can be concluded that the influence and sensitivity of window-wall ratio on the total energy consumption are related to the operation mode of air conditioning system, the orientation of outside window, and the glazing types of window. The influence of the factors can be regarded as reference mode for the window-wall ratio when designing residential buildings.

Potential of Energy Saving from Daylight Usage under Ministerial Regulation

To enhance the use of daylight, lighting power density (LPD) load in building can be deducted by designing for energy conservation according to ministerial regulation’s conditions. However, the methods and benefits are not clearly defined. These problems also affect architectural design framework. This is an experimental research aims to explore the potential of daylighting by using DIALux software to simulate daylight level in office building. The results indicate that 1) within the room depth of 1.5 times window head height; most of the results from 4 types of studied windows cannot provide adequate illuminance (300 lux) on workplane. Artificial lights are still needed to be turned on to maintain minimum illuminance level. Therefore, the energy saving purpose is unachieved. 2) The orientation of windows affects on both illuminance and distance of useful daylight. 3) With proper design integration, it is possible to reduce glazing area. 4) Skylight is an effective mean to introduce and distribute daylight into building. 5) For visual comfort issue, daylight quality should be concerned. Finally, the results of this research will propose guidelines for developing design criteria and evaluation method in the future. This will reflect the actual energy consumption and saving.

Comparative Study of Two Daylighting Analysis Methods with Regard to Window Orientation and Interior Wall Reflectance

The accuracy and speed of the daylighting analysis developed for use in EnergyPlus is better than its predecessors. In EnergyPlus, the detailed method uses the Split-flux algorithm whereas the DElight method uses the Radiosity algorithm. Many existing studies have addressed the two methods, either individually or compared with other daylight analysis methods like Ray tracing but still there is lack of detailed comparative study of these two methods. Our previous studies show that the Split-flux method overestimates the illuminance, especially for the areas away from the window. The Radiosity method has the advantage of accurately predicting this illuminance because of how it deals with the diffuse light. For this study, the EnergyPlus model, which has been calibrated using data measured in a real building in previous studies, has also been used. The calibrated model has a south oriented window only. This model is then used to analyze the interior illuminance inside the room for north, west and east orientation of the window by rotating the model and by changing the wall reflectance of the model with south oriented window. Direct and diffuse component of the illuminance as well as the algorithms have been compared for a detailed analysis.

Effects of the splayed window type on daylighting and solar shading

Solar shading is generally considered to be used in hot or similar climates; however in certain climates with high solar radiation and high diurnal temperature variation, solar shading for windows is also necessary. A typical type of shading for this climate is the splayed window. An investigation of the performance of daylighting and solar shading of this window type can benefit the solar shading design for similar climates.This paper identifies the influencing factors of the splayed window type in daylighting and solar shading and ranks their importance factors via an orthogonal experimental design. Next, the detailed effects of the dimensional factors are investigated for a window of western orientation for a case in Lhasa via a series of simulations using Radiance and Daysim. Afterwards, the performances of this window type in other locations are examined.The results reveal that the ratio of the exterior and interior window opening areas and orientation have significant influences on the integrated performance in daylighting and solar shading, and the West orientation is identified to be the best for usage of this window type. Similar performances are found in other locations and RDA/SC is found to have a strong positive correlation with the incident solar radiation and the splayed window will be more effective in locations with high incident solar radiation in terms of solar shading and daylighting.

Improving thermal performance of automatically generated floor plans using a geometric variable sequential optimization procedure

This paper presents an approach for the optimization of floor plan designs. These are generated using a hybrid evolutionary approach, which produces alternative designs according to the user’s preferences and requirements. Once generated, an optimization algorithm is used to improve the thermal performance of each solution. The algorithm evaluates each possible transformation for several design variables in each floor plan, such as floor plan orientation and reflection, window orientation and size, overhang size, fin size, and wall translation. A geometric variable sequential optimization procedure is used to satisfy the user’s design strategy.A case study of a single-family house is carried out, where two design sets, with 12 alternative solutions each, are generated, assessed, and optimized according to thermal performance criteria. The results demonstrate that the thermal performance of the floor plans may improve by up to 41% for single-level solutions and 54% for two-level designs. When comparing solutions within each design set, the floor plan design which ranks first is 33% and 29% better than the worst design, in the first and second design set respectively.

Multi-criteria decision analysis to select the optimum position and proper field of view of a photosensor

The lack of knowledge concerning the commissioning of a daylight responsive system constitutes a serious impediment to their widespread use. Furthermore, installation details and tools regarding their photosensor position and field of view (FOV) are insufficient. This paper presents a decision making method capable to estimate the best position of a photosensor on the ceiling and its proper FOV based on multiple criteria analysis. The criteria used are (a) the correlation of the lighting levels between the working plane and the ceiling, (b) the corresponding energy savings and (c) the lighting adequacy which is defined as the percentage for occupied time with total illuminance exceeding design illuminance (i.e 500lux EN 12464-1, 2011) and is strongly affected by the control algorithm.A number of simulations with variable FOV and position of photosensors were performed in order to clarify the calculation procedure of the proposed methodology. Three different typical room geometries have been used with variable window sizes and orientation. Furthermore a prototype photosensor with variable FOV through the use of a telescopic cylinder was constructed and placed in a scale room (1:10) in order to verify the results of simulations. The verification was based on a set of experimental procedures concerning measurements of the spatial response of the prototype photosensor (for various FOVs) and measurements of ceiling/workplane illuminance inside the scaled room for various combinations of position and FOV of the photosensor. The proposed methodology can be used as a tool for the determination of the optimum operation of a daylight responsive system with photosensors.

A METHOD OF OPTIMIZING FENESTRATION DESIGN FOR DAYLIGHTING TO REDUCE HEATING AND COOLING LOADS IN OFFICES

Modern office building designs tend to increase the window share per facade to make the building more impressive with extensive visibility and well daylit rooms. In general, an increased window share results in higher energy usage and higher costs of heating and cooling, but these disadvantages can be reduced with a more careful design. The aim of this paper is to show the influence of window design and room layout on heating and cooling demand and daylight availability in office buildings in northern Europe. The results in the paper are based on design calculations for two different room types and daylight measurements on two room scale models in a daylight laboratory. The calculations show the influence of window design parameters on the cooling and heating demand. The daylight measurements show the influence of window design parameters on the availability of daylight. The results have then been combined to show a feasible window design regarding daylight availability and the resulting cooling and heating demands for different window orientations. The results show that in most cases it is possible to find a combination of window share and window solar factor that is feasible with regard to daylight as well as cooling and heating. The main finding is that there is a smaller or wider range of feasible designs for different window orientations.

A method for eliminating Faraday rotation in cryostat windows in longitudinal magneto-optical Kerr effect measurements.

A solution to the problem of disturbing effect of the background Faraday rotation in the cryostat windows on longitudinal magneto-optical Kerr effect (LMOKE) measured under vacuum conditions and/or at low temperatures is proposed. The method for eliminating the influence of Faraday rotation in cryostat windows is based on special arrangement of additional mirrors placed on sample holder. In this arrangement, the orientation of the cryostat window is perpendicular to the light beam direction and parallel to an external magnetic field generated by the H-frame electromagnet. The operation of the LMOKE magnetometer with the special sample holder based on polarization modulation technique with a photo-elastic modulator is theoretically analyzed with the use of Jones matrices, and formulas for evaluating of the actual Kerr rotation and ellipticity of the sample are derived. The feasibility of the method and good performance of the magnetometer is experimentally demonstrated for the LMOKE effect measured in Fe/Au multilayer structures. The influence of imperfect alignment of the magnetometer setup on the Kerr angles, as derived theoretically through the analytic model and verified experimentally, is examined and discussed.

Daylighting on the working plane in oriented attic rooms under overcast and clear sky

Abstract The evaluation of daylight conditions in building interiors is based on the Daylight Factor concept after current Slovak standards. Criteria and requirements determined in these standards consider the worst daylight exterior conditions which are described by CIE overcast sky model. The sky luminance distribution of overcast sky is centrical to the zenith, so independence of window orientation to cardinal points is characteristic in daylighting calculations. The sky luminance distribution modelling is one of the main task of the daylight source research more than 50 years. It is evident that also other types of sky conditions exist in nature. An introduction of a new criterion based on photometric variables, which also consider sunlight influence, is expected. This article represents a study of the influence of the interior orientation on distribution of daylighting in attic spaces under an overcast and clear sky

Analysis of energy demand in residential buildings for different climates by means of dynamic simulation

The aim of the present paper is to propose an analysis of energy consumption of a standard building in different climates. The analysis is developed by simulating the dynamic behaviour of the building subjected to different climatic conditions according to the considered location. Simulations are performed by means of an in-house developed code, validated by comparison with the outcomes from leading software, particularly TRNSYS and EnergyPlus. The use of a self-developed code guarantees a high flexibility and allows the implementation of new capabilities if necessary. The impact on the energy consumption of various parameters, namely internal and external wall insulation, window surface areas, thermal capacity and orientation, is investigated. Results show that the insulation of external walls has a fundamental role in reducing energy consumption, because it allows to exploit the thermal capacity of the walls. This is particularly useful for buildings which necessitate to keep the internal temperature constant.

Green buildings for greying people

Purpose – This paper aims to identify the critical issues to be considered by developers and practitioners when embarking on their first green residential retirement project in Australia. With an increasingly ageing population and widespread acceptance of the need for sustainable development in Australia, the demand for green retirement villages is increasing. Design/methodology/approach – In view of the lack of adequate historical data for quantitative analysis, a case study approach is used to examine the successful delivery of green retirement villages. Face-to-face interviews and document analyses were conducted for data collection. Findings – The findings of the study indicate that one of the major obstacles to the provision of affordable green retirement villages is the higher initial costs involved. However, positive aspects were identified, the most significant of which relate to the innovative design of site and floor plans; adoption of thermally efficient building materials; orientation of windows; installation of water harvesting and recycling systems, water conservation fittings and appliances; and waste management during the construction stage. With the adoption of these measures, it is believed that sustainable retirement development can be achieved without significant additional capital costs. Practical implications – The research findings serve as a guide for developers in decision-making throughout the project life-cycle when introducing green features into the provision of affordable retirement accommodation. Originality/value – This paper provides insights into the means by which affordable green residential retirement projects for aged people can be successfully completed.

Noise annoyance is related to the presence of urban public transport

BackgroundThe association between noise annoyance and public transport as a source of noise has not been studied previously. The aim was to study noise annoyance in an urban population due to the presence, the type and the number of public transport vehicles, in relation to other acoustical and non-acoustical parameters. MethodThe study sample comprised 5861 adults residing in 118 streets in the city center of Belgrade. The presence, the type and the number of public transport vehicles were assessed using official transport maps and matched with residential addresses. Noise annoyance was assessed by a questionnaire including a self-report five-graded scale. ‘High noise annoyance’ was defined by merging ‘very’ and ‘extremely’ annoyed answers. ResultsSignificant predictors of high noise annoyance were the presence of public transport at daytime (yes vs. no) (odds ratio=1.47, 95% confidence interval=1.28–1.70), and at night (yes vs. no) (OR=1.39, 95% CI=1.20–1.61). Residing in the streets with more than 79 public transport vehicles per hour (3rd tercile vs. 1st tercile) predicted high noise annoyance at daytime (OR=1.64, 95% CI=1.18–2.27). Residing in the streets with buses and trams at night (‘bus and tram’ vs. no public transport) increased the risk of high noise annoyance (OR=2.67, 95% CI=1.78–4.09). These associations were independent from noise sensitivity, orientation of bedroom windows, floor level, and equivalent noise levels. Living in the apartment with bedroom windows facing the street was the strongest confounder for the association between noise annoyance, noise levels and public transport. ConclusionThe study has identified the presence of public transport at daytime and at night as a significant and independent predictor of high noise annoyance. Future intervention measures should concern the presence, the type and the number of public transport vehicles in order to reduce noise annoyance reactions in urban areas.

공동주택의 주동 유형별 냉난방부하 분석

This study focuses on the analysis of the cooling and heating load in accordance with apartment houses arrangement type using Ecotect Analysis. Korea have to reduce energy consumption part of building except in industry and transport because the rate of dependence on imports amounts to 94%, Apartment houses built in various forms in order to reduce energy are modelled in each window area ratio, shape, orientation, and climate through simulation. Through this study, we can analyze the cooling and heating load by form, window area ratio, orientation, and climate change and know the optimal elements by the form. In particular, although there have been done research on the window area ratio and the arrangement form, the research of the regional climate characteristics and the direction are hardly carried out. To supplement those problem, adding to seven direction and climatic element of southern region is characteristic(L Type, Y Type, - Type) of this study. The form of apartment houses built 10 years ago is modelled for simulation.

Thermal properties optimization of envelope in energy-saving renovation of existing public buildings

Abstract The shape factor and windows-to-wall ratio are different from building to building. How to design the thermal properties of building envelope affects energy-saving renovation economy of existing public buildings. The limited heat consumption per unit volume and equivalent heat transfer coefficient of external windows and wall were proposed based on the prescription of China national standard “Design standard for energy efficiency of public buildings”(GB50189-2005) for envelope design. Mathematical model on economical thermal insulation thickness of building envelope and thermal properties optimizing of envelope were built considering the impact of house orientation, windows-to-wall ratio and types of windows. The model is verified to be feasible by an existing public building in Shenyang. The variation of windows-to-wall ratio for different orientation leads to the different economical thermal insulation thickness of building envelope and payback period. The project optimization design for envelope renovation could be determined by the technical and economic analysis considering the impact of house orientation, windows-to-wall ratio, types of insulation materials and windows.

Life cycle assessment model applied to housing in Chile

Complying with international agreements regarding environment, and particularly the reduction of greenhouse gases emissions, requires appropriate policies in the building sector. This study concerns single family housing in Chile. The aim of this work is to develop knowledge in order to define and prepare implementation of design procedures to minimize the environmental impacts without reducing the level of comfort in such buildings. The model presented is based upon the life cycle assessment methodology. Buildings are described including geometry and technological elements. Thermal simulation is used in a first step to evaluate heating and cooling loads, and to check the level of indoor comfort in summer. The results constitute an input to a life cycle simulation tool, integrating the fabrication of materials, construction, use of the building, maintenance and end of life. Environmental indicators like the global warming potential are evaluated. Other indicators concern air pollution, natural resource consumption, waste production etc. This model has been adapted to the Chilean context, particularly regarding the electricity production mix and climatic conditions, considering four climate zones characteristic of the country. In each zone, a typical social housing unit is defined and the corresponding environmental impacts are evaluated. Various technical and architectural solutions are studied, particularly: increased insulation thickness (applying thermal regulation), orientation of windows and glazing types. The performance improvement is higher in cold climates. A reduction of CO2 emissions up to 50% is estimated, and other technical measures are suggested to improve the performance further. According to these results, reducing energy related impacts does not increase other damage indicators related to e.g. human health and biodiversity.

Thermal Stability of the Summer Period in Schoolrooms

Schoolrooms in school facilities are the most problematic in maintenance of the internal microclimate and that is why, they have strict hygiene requirements. The generated pollutants in this space are not only affected by the presence of people but especially by solar radiation and orientation of doors and windows to the cardinal points. Considerable importance have the size of the windows, because the room must meet the standards criteria for minimum daily requirement of iluminance Dmin. Increasing outdoor temperature, solar radiation and stay of persons in the classrooms are important aspects that irreversibly lead to deterioration of the microclimatic conditions in these areas. This leads to premature fatigue, loss of concentration, which may lead to headaches, for example. This paper aims to determine the impact of available instruments commonly used in practice to reduce the thermal load of sunlight in the classrooms and determine the actual effectiveness of individual instruments in the real environment.

Association between road traffic noise and prevalence of coronary heart disease

There is an established evidence that exposure to high levels of road traffic noise is associated with elevated risk of coronary heart disease (CHD). The results however have been heterogeneous and mostly inconclusive. The present investigation aimed to examine this association in adult subjects, with a secondary aim of identifying potentially vulnerable sub-populations. Similar studies have never been reported from Indian population. For exposure assessment, the time-weighted road traffic noise indicator, L den, was used as a continuous and categorical predictor. A cross-sectional study was designed, and sociodemographic and lifestyle- and health-related characteristics were recorded for 909 (533 females and 376 males) subjects aged 18-80 years. The respondents living in areas with L den < 60 dB(A) were designated as the reference group. Odds for self-reported CHD in relation to traffic noise exposure were estimated by univariate and multifactorial logistic regression with adjustments for potential confounders and effect modifiers. The adjusted odds ratio (OR) for self-reported CHD was 1.72 (95 % CI 1.36-2.19) per 5 dB(A) increase of L den (range 55-80 dB(A)). A gender-related risk difference was observed among male (OR 1.47 (1.07-2.02)) and female (OR 1.83 (1.27-2.65)) respondents. A stronger effect for subjects in the age group 55-64 years old was found, with age, residence period, body mass index, and self-reported stress being significant confounders. This study suggests epidemiological evidence that exposure to road traffic noise of L den > 65 dB(A) may be associated with occurrence of CHD in adult subjects. A trend was observed indicating increasing risk with higher exposure levels. The study results are also suggestive of higher risk of outcome among those with other chronic ailments (diabetes, pulmonary, or renal issues) and residing in the same location in excess of 15 years. Orientation of bedroom windows was identified as a significant effect modifier.

Passive performance of glazed components in heating and cooling of an open-space office under controlled indoor thermal comfort

According to the Fanger's comfort theory, the individual thermal sensation is mainly connected with the thermal balance of the human body. This balance and the related comfort indicators (the Predicted Mean Vote, PMV, and the correlated Predicted Percentage of Dissatisfied, PPD) depend on four environmental parameters (air temperature, humidity and velocity, and internal envelope mean radiant temperature) and two variables connected with the human being (physical activity and clothing). Differently from the other environmental parameters under the system control, the mean radiant temperature is strongly conditioned by the envelope characteristics, and in particular, by the presence of glazed surfaces whose insulating performance is commonly lower than the one of opaque components. Transparent components also admit solar radiation into the indoor environment, affecting the thermal balance of the building and of the occupants.In this paper, the heating and cooling energy needs of an open-space office with different windows' characteristics have been analyzed under controlled internal comfort conditions. A set of configurations given by different windows' glazing systems, area, disposition and orientation has been simulated, considering the climatic conditions of Paris, Milan and Rome. The passive energy performance of the different glazing solutions has then been compared accounting for the long-term comfort conditions (on seasonal basis). The time distribution of the Predicted Mean Vote (PMV) and the Discomfort Time weighted by the Predicted Percent of Dissatisfied (WDTPPD) are analyzed, including also the effect of the diffuse and beam solar radiation directly reaching the occupants through the windows.