Sigrid Reiter

Passive designs and strategies for low-cost housing using simulation-based optimization and different thermal comfort criteria

An optimum design of low-cost housing offers low-income urban inhabitants great opportunities to obtain a shelter at an affordable price and acceptable indoor thermal conditions. In this paper, the design and operation of a low-cost dwelling were numerically optimized using a simulation-based approach. Three multi-objective cost functions including construction cost, thermal comfort performance and 50-year operating cost were applied for naturally ventilated and air-conditioned buildings. Thermal environment inside the house was controlled and assessed by two thermal comfort models. Optimization problems which consist of 18 design parameters and 6 ventilation strategies were examined by two population-based probabilistic optimization algorithms (particle swarm optimization and hybrid algorithm). Optimum designs corresponding to each objective function, differences in optimal solutions, energy saving by the adaptive comfort approach and optimization effectiveness were outlined. The optimization method used in this paper shows a considerable potential of comfort improvement, energy saving and operating cost reduction.

Toward Low Energy Cities

Summary Within the framework of sustainable development, it is important to take into account environmental aspects of urban areas related to their energy use. In this article a methodology is proposed for assessing residential energy uses for buildings and transport at the city scale. This method is based on the use of geographic information system (GIS) tools combined with a statistical treatment of urban and transport criteria. The methodology allows us to model building and transport energy use at the city scale, as well as to consider the possible evolution of city energy consumption and to simulate the effects of some strategies of urban renewal. An application is given to study different energy management strategies for the urban area of Li` ege, Belgium. Building and transport energy consumption are compared at the city scale and their possible evolution in the future is highlighted. Forecast scenarios

A method to evaluate the energy consumption of suburban neighborhoods

Energy use in buildings, transportation systems, and lighting networks represents a significant contribution to the overall energy consumption in urban and suburban areas. This article presents a method to evaluate the energy consumption of suburban neighborhoods from these three points of view, aiming to highlight the most relevant variables linking urban form and neighborhoods’ energy consumptions. The method includes three parts: (1) a computational approach combining dynamic simulation tools and a database of building typologies to determine the energy consumed in heating; (2) an empirical approach to assess the energy consumed by transportation systems (four purposes of travel are taken into account: work, school, leisure, and shopping); and (3) a simplified approach to calculate the energy consumed by public lighting. Results from the application of the method to three characteristic suburban neighborhoods in Belgium are presented along with a life cycle energy assessment of buildings. A sensitivity analysis was conducted to determine the effects of building and neighborhood characteristics and of building inhabitant behavior on calculated energy consumption. Results from the analysis show that building insulation, building distribution, heating system management, and neighborhood location are critically important factors in the energy efficiency of suburban residential areas.

Bioclimatism in Architecture : an evolutionary perspective

The well-known Darwinian evolutionary theory (1859) introduced natural selection as the most important mechanism of evolutionary processes at every level from biological systems, including species, individual organisms... to molecules, such as DNA or proteins. In architecture we observe similar evolution processes, which lead to the development of various architectural movements and concepts from common primitive living structures. Fundamentals of vernacular architecture have been used in bioclimatic architecture, which has gradually become the inspiration of various movements in contemporary architecture. The study points out that the development of bioclimatism in architecture has followed the pattern of a natural evolutionary process in which ‘natural selection’ is likely motivated by several factors, including resources and environment problems, and driven by different mechanisms including novel building design concepts and methods, new standards and codes, discoveries in building science and construction costs. This study is an effort aimed to clarify the evolution process of the bioclimatic approach in architecture over time and its influences on contemporary movements in architecture. The paper shows also that the evolutionary theory generated new scientific tools able to improve building design thanks to simulation-based optimization methods applied to building performances. Finally, this study investigates new motivations in the era of climate change whose effects are expected to introduce more challenges as well as more trends towards a sustainable built environment through the new concept of Eco-adaptive architecture.

The efficiency of different simulation-based design methods in improving building performance

This paper presents a pioneering effort to define the efficiency of the most common simulation-based design methods, namely the parametric simulation method (PSM) and the simulation-based optimization method (SOM), in improving two building performance indicators: thermal comfort and energy consumption. Three case-study houses were selected and their indoor conditions were continuously monitored during one summer month in 2012. Computer EnergyPlus models of these houses were established and then carefully calibrated by the monitoring data to improve the reliability of the numerical methods. Thermal performances of these houses during a year were simulated, then improved by the PSM and finally optimized by the SOM. By comparing the results of these two simulation-based design methods, this research found that both the PSM and SOM were very effective in improving these building performance indicators. This study found that the SOM is almost two times more efficient than the PSM in improving thermal comfort in naturally ventilated (NV) houses and life cycle cost in air-conditioned (AC) houses. In average, the discomfort period in NV houses could be reduced by 44.9% by the PSM while as high as 86.1% by the SOM, compared with the reference cases. The life cycle cost of AC houses had smaller reductions with 6.2% and 14.6% cut-off by the PSM and SOM, respectively. The results of this work give a strong and explicit insight of the actual efficiency of each design method. This work also shows great advantages of applications of advanced numerical approaches in the design of high performance buildings.