1. Passive Solar Design

Transcription

1 During the conceptual design phase of urban areas, the designer deals with different geometrical characteristics of the project Design Tools for Solar and Daylight Access in Urban Design Climate and Energy Laboratory Faculty of Architecture and Town Planning Technion Israel Institute of Technology Haifa, Israel May 27, 2010 orientation height open spaces sidewalks proportions width wind regime daylight access shading solar rights early stages of this process characterize themselves by a constant search for a design direction decisions taken in those moments can determine the success or failure of the proposed project the need> design tools could support architects from the beginning of the design process Outline The need 1. Passive Solar Design Solar Rights Passive Solar Heating of Buildings The The tools gap Comfort conditions in open spaces, Insolation and Shading 2. Active Solar Systems solar water heating Compulsory in Israel for residential buildings MUST protect solar rights photovoltaic panels (BIPV) part of the building envelope Roofs Facades 1

2 January February March April May June July August September October November December hour 3. Daylight Access Lighting is responsible for 30% to 50% of all the energy utilized in commercial and office buildings. availability of daylight in certain areas of the city can be difficult Sky View Sky Solid Angle SSA avoid glare Energy demands per hour in an office building by end-uses on a summer day (left) and annual electricity production in Israel by type of fuel (right). Source: Israel Electric Company, 1994 and Design Tools: : aid to define the proper geometry (space of solutions) to achieve a certain performance Evaluation: analyze the performance of a given design alternative Evaluation +: (support generation) Global horizontal solar illuminance (lux) in Tel Aviv (Lat:32deg N, Long:35 deg E) disadvantages: Input of evaluation models needs detailed information and precision not known and not relevant at the beginning. Tools can also have complex interfaces that require much time to learn and use. Both factors can distract from the design activity itself. Early design decisions are based on vague ideas that cannot be evaluated with tools that rely on exact data. They require complex input procedures, together with translations from one format type to another. Most tools are dedicated to evaluate a certain finished alternative, not to suggest and evaluate different design options and directions. This implies fitting an idea to the modeling tool, thus filtering out information that could be useful or distorting the process. Trial and error approach. Most evaluation programs are designed for use by consultants, generally engineering companies that enter the design field very late, when main geometric characteristics of the building are already fixed. For complex projects on the boundary of his or her expertise, the designer has few criteria about which design direction to develop in order to pass from idea to design concept. How design tools can support the design process? help to generate new set of questions what if? what to do next? support architects from the beginning of the design process; one 3D model suggest solutions present evaluations that help to generate design solutions help architects making informed design decisions towards high-performance urban design 2

3 Evaluation + Design Tools SustArc Solar Rights Envelope SRE Heliodon software number one for designers SustArc SustArc Solar Collect Envelope SCE Solar Volume SV DESIGNING AN URBAN BLOCK INSOLATION PERIOD: November-March 10:00AM 2:00PM The Solar Volume for a new area SRE = SV SOUTHERN FAÇADE & SUN DECK EXPOSED TO SUN SUNNY SIDEWALKS Sun deck 3

4 Visual evaluation. The isometric views were produced from the sun s point of view for Dec. 21 st at 2 P.M. (winter) and June 21 st at 2 P.M. (summer) Solar Rights: An example from Israel Increasing Building Density: 450% SOUTHERN FACADES, SUN DECK AND SIDEWALKS EXPOSED TO WINTER SUN December 2 P.M. TREES ADDED TO CAST SHADE IN SUMMER DO NOT ADD SHADED AREAS IN WINTER June 2 P.M. Proposed Plan Evaluation: Sun views and Periodical Shade during a winter day Capeluto I.G., A. Yezioro and E. Shaviv, "Climatic Aspects in Urban Design A Case Study", Building and Environment, Vol 38/6 pp (+evaluation) Blue envelope Protecting the main green avenue and the residential neighborhood A simple method for considering solar rights based on Solar Envelopes It presents the use of solar section lines as a simple tool for solar rights design. Designing according to these section lines ensures the solar rights of the surrounding buildings and open spaces, without the need to demonstrate further requirements. solar rights regulations According to the insolation hours which meet the radiation requirements. The designer has to present the proof of keeping the surrounding buildings exposed to the sun during that time. REQUIRED HOURS OF INSOLATION FOR MOUNTAIN AREA (JERUSALEM) Periphery Center Periphery Center Periphery Center Periphery Center Periphery Center JERUSALEM Azim=90 sc50/40 Azim=135 sc80/65 Azim=180 sc80/65 Azim=225 sc80/65 Azim=270 sc50/40 sc 50 sc 40 sc70 sc55 sc 80 sc65 sc 70 sc55 sc 50 sc 40 required December : : : : : : : : : : : : : : Total obtained

5 1. Keeping Solar Rights of Residential Buildings The section lines defined for the descriptive method are based on solar envelopes that were created according to the required hours of insolation for each orientation for the four different climatic zones in Israel and for both central and peripheral areas. In central areas, where lower floors may be used for commercial purposes the base point of the section lines will rise up 2. Keeping Solar Rights of Sidewalks Evaluation + SunTools plugin forsketchup presenting information with new meaning valuable for design generation 1 to 2 meters The requirement for sidewalk insolation is that at least 1 to 2 meters of its width will be insolated. The demand is for only one sidewalk to be exposed at a time. sun_path sun_position sun_penetration/solar_access 5

6 DFave(%) Assessing Sun Penetration Using SunTools Modifying the Design >> Skylight Assessing Sun Penetration Using SunTools sky_view Modifying the Design >> Skylight Assessing Sun Penetration Using SunTools The external obstructions and the visible sky patch as viewed by Radiance from a window located at floors 2, 4, 8 and SSA(sr) The sky solid angle (SSA) as calculated by Sustarc from a window located at floors 2, 4, 8 and 12, in a building facing an irregular obstruction pattern Dependence of average daylight factor (DFave) for office spaces on the solid angle subtended by the visible patch of sky (SSA) from the center of the window 6

7 sky_view sky_view sky_view 12:00 sun_view 11:00 10:00 October 21 15:00 14:00 13:00 Shadows Axonometric View from SUN 7

8 periodical_shade Proposed Plan Evaluation + IR4SU plugin for SketchUp (in progress) irradiance_calculator_for_sketchup (EranAmir & Guedi Capeluto) sun_position (SketchUp) epw / tmy climate based irradiance mapping We have not succeeded in answering all our problems. The answers we have found only serve to raise a whole set of new questions. In some ways we feel we are as confused as ever, but we believe we are confused on a higher level and about more important things...". Thank you...!! Posted outside the mathematics reading room, Tromsø University (via Bernt Øksendal, Stochastic Differential Equations). 3d working model arrguedi@technion.ac.il 8