Laboratory Simulation Techniques in the Design Process to Promote Sustainability in Architecture
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Laboratory simulation techniques in the design process to promote sustainability in architecture Julian Martin Evans Research Centre Habitat and Energy, Laboratory of Bioclimatic Studies, Faculty of Architecture, Design and Urbanism, University of Buenos Aires, Argentina. ABSTRACT: The aim of this paper is to demonstrate the implementation of techniques and spatial simulation during the design process and to document studies, which have been carried out in the Laboratory of Environmental Studies, Research Centre Habitat and Energy, FADU, UBA. These studies, with artificial sky, wind tunnel and multiple sun heliodon, complemented by numerical simulation, allow the design team to evaluate initial design decisions, to improve design features and construction characteristics that contribute to sustainable buildings. These studies and laboratory tests supports the integration of results in project development. The examples of different character and scale demonstrate a variety of aspects that contribute to sustainability in practice by controlling climatic impacts, evaluating design alternatives and assessing results at early stages of the design process. This is promoting innovation in architectural practice, through research, teaching and transfer to professional practice. Conference Topic: 2 Design strategies and tools Keywords: simulation, sustainability, design process, environmental impact. INTRODUCTION 2. STUDIES IN THE LABORATORY Architecture projects are generally conceived, The laboratory studies presented in this paper defined and developed as visual objects, expressing correspond to different scales: urban, architectural their three-dimensional shape through drawings and and construction. To obtain relevant results in each models. The visual emphasis in the design process case, different tests were carried out, using the wind minimizes the importance of the environmental impact tunnel, heliodon, artificial sky and/or computer of the project. On the other hand, architectural software applications, such as numerical simulations morphology and construction details have a great of natural lighting, thermal performance, heat flow, air influence in the conditions of the building: solar flow, shading, solar radiation impact and acoustic impact, daylight, running costs, natural ventilation, performance. right to light, thermal performance and indoor comfort. The different cases analysed include projects in Energy consumption for heating, cooling, lighting, the early design stages, built examples and re-cycling ventilation and other environmental characteristics of and modification of existing buildings as well as the building are a direct result of design decisions. research studies and students projects. A selection of The environmental quality of indoor and outdoor different cases and alternatives are presented in spaces depend on visible elements as well as factors Table 1. difficult to visualize, such as wind patterns, heat flow A wide diversity of the examples are shown in the and natural convection, resulting from building shape paper, from different and often extreme geographical and three-dimensional characteristics of the urban locations, covering the varied climates of Argentina tissue. In this context, there is a need to develop and other countries, including Spain and Uruguay, techniques, which will let the design team visualize, demonstrating the importance and scope of the tests study and comprehend environmental phenomena. carried out. This paper presents a series of different projects, from international competitions, students work, design 2.1 Objectives concepts and built examples in different climates, Test in the laboratory have shown benefits in scales and contextual situations, studied from early pursuing and improving the sustainable qualities of design stages through simulation tests in the projects, making good use of efficient lighting, and Laboratory of Environmental Studies, LES. energy initiatives, with the aim of optimising comfort It demonstrates the way in which laboratory tests conditions of future occupants. With smoke from wind have contributed to project development, improving tunnel tests, air flow is visualized in indoor spaces conditions for sustainability, controlling climatic and around buildings. Shadows in the heliodon show impacts and providing a quantifiable and objective e•posure to direct radiation and shadows, according base to support the design process. to hour of day, latitude and season [1]. The Laboratory of Environmental Studies, LES, has different items of equipment, measuring instruments and numeric simulation programs which allow experimentation and simulation of the performance of projects, through the use of scale models and virtual models during the design process. Also, different equipment has been used to verify the behaviour of existing buildings. The development of numeric simulation programs which allow visualization of different phenomena, such as the impact of the solar radiation and wind, thermal energy flows, acoustic performance and lighting behaviour of a building. The calibration and testing of these programs is only possible by means Figure 1: Directly controlled multiple sun heliodon of measuring the physical phenomena. Without and low speed open-jet wind tunnel. measurements and physical tests using scale models, simulation programs can offer convincing but often erroneous results. This situation shows the importance of complementing numerical studies with parallel tests in the Laboratory, to verify and calibrate results for research, teaching and practice, providing support for design. From the beginning, a strong emphasis was placed on the ease of use by students and members of the design team, to promote understanding and comprehension of the visual and spatial phenomena observed. Most important of all is the possibility of allowing designers and researchers to modify and compare alternatives in the laboratory, testing Figure 2. Instrument for measuring potential sunshine different strategies and alternative solutions, at specific latitudes on site, indoors and outdoors. especially in the initial stages of the design process. 2.2 Equipment The Laboratory of Environmental Studies [2], initiated in 1986, houses the following equipment shown in Figures 1-4: Heliodon: 4 m diameter multiple sun model, for all latitudes from equator 0° to poles 90°, using 150 watt clear incandescent bulbs, with a horizontal fixed working plane for easy visualisation and manipulation of working models. Wind tunnel: The low speed open-jet tunnel with simulation of wind gradient sharing the heliodón working plane, and variable wind speed allows direct observation and recording of test results. Artificial sky: 2,6 m • 2,6 m mirror-type sky with Figure 3: Meteorological station with instruments for stretched membrane diffuser, producing 6,000 lux on measuring solar radiation and illuminance. the working plane and calibrated CIE diffuse light distribution [3]. Met station: The station, the first of it’s type in Latin America, is located on the roof of the faculty, with 4 years of continuous records. Measurements of temperature and humidity are recorded at half hourly intervals, while solar radiation and illuminance are registered at one minute intervals. Instruments: Different measuring instruments, such as light-meters, photometers, pyranometers, hot-wire and vane anemometers, are essential tools to quantify the different environmental variables which affect sustainability, comfort and sensations of well- being. Mini-data loggers, instruments for measuring reflectivity, humidity in walls, and hours of potential sunshine are also employed both in the laboratory Figure 4: Mirror-type artificial sky [2] and photometer. and measurements on site. 3. LABORATORY CASE STUDIES 3.1 Testing projects and competition proposals Figure 5: Provincial Education Board, Neuquén. Figure 8: Ezeiza International Airport, Buenos Aires. Heliodon and wind tunnel studies, showing the Sun path studies in a large scale projects, permanent shade from building and wind break tree comparing different structural solutions and façade barrier, using multiple shadows. Verification of solar alternatives to the control of thermal and visual penetration and wind protection in public spaces and conditions indoors. its incidence in the surrounding areas. Morphological study of the building and characteristics of exterior spaces. Figure 9: Shadows of Towers, Barcelona, Spain. Figure 6: Site selection for optimum solar orientation Sun path and shading studies, visualising hours of and views in an ecological complex, Merlo, San Luis. sunlight and conditions in the surrounding spaces and between building elements, to justify variations in Study of the topography at an early stage in the building height. This analysis shows the importance of design process to analyse the surroundings, select project testing at early stages of the design process. building locations and verify the influence of the surroundings on the project. Figure 10: Palace of Justice, Barcelona, Spain. Figure 7: Cultural centre, Punta del Este, Uruguay. Sun path test. Measurement of solar impact on Studies of solar incidence on glass roof and its the building and hourly incidence on different facades, influence in interior conditions using heliodón and e•terior spaces, as well as reflections between thermal simulation. Studies of alternative glass types elements and on the atrium roof, in order to and shading devices, together with analysis of solar