Design guidelines for appropriate insolation of urban squares

 Religion & Spirituality

 4 views
of 13
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Description
Design guidelines for appropriate insolation of urban squares
Share
Tags
Transcript
  Design guidelines for appropriate insolationof urban squares A. Yezioro * , Isaac G. Capeluto, E. Shaviv Faculty of Architecture and Town Planning; Technion - Israel Institute of Technology; Haifa, 32000-Israel Received 20 October 2004; accepted 19 May 2005Available online 26 July 2005 Abstract A systematic study of building design around urban squares, while keeping the solar rights, ispresented. The assessment was carried out both visually and quantitatively using the modelSHADING (Solar Energy. 1994; 52-1, 27-37). The quantitative evaluation is general and allows afast and efficient evaluation of the Geometrical Insolated Coefficient (GIC), which is the ratiobetween the insolated area and the total examined area. The calculation of the GIC was carried outyear around for different proportions of squares and buildings heights around them. By calculatingthe Average GIC for Winter for each examined square, recommendations and design guidelines arederived and presented. q 2005 Elsevier Ltd. All rights reserved. Keywords:  Urban squares; Solar rights; Geometrical Insolated Coefficient 1. Introduction Urban squares may differ in their proportions, i.e. the length to width ratio, and theheight of buildings around them. The geometry of the urban square affects the shadingzones created in it. Consequently it determines whether the place will be thermallypleasant or uncomfortable during different hours of the day and throughout the year. It ispreferable to design the urban square so that a large portion of it is insolated in winter.Although shading is very important in summer, the design of the urban square shouldmainly consider winter solar exposure. This is because summer shading may be achieved Renewable Energy 31 (2006) 1011–1023www.elsevier.com/locate/renene0960-1481/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.doi:10.1016/j.renene.2005.05.015 *  Corresponding author. Tel.: C 972 4 829 4044; fax: C 972 4 829 4617. E-mail address:  ayez@techunix.technion.ac.il (A. Yezioro).  by dynamic solutions, like deciduous trees (as will be demonstrated in Fig. 7) or bypergolas with a light cover that can be folded in winter. On the other hand, insolationcannot be added in winter if the buildings around the square block completely the sun. Thedesign parameters that determine the insolation of the urban square are the height of thebuildings around it, its orientation and proportions.The important afore mentioned effects of appropriate solar rights design of open spaceswere recognized more than forty years ago by Olgyay and Olgyay [1]. The energy crisis of  1973 accelerated attempts to find advanced methods and tools for the design andevaluation of suitable insolation of open spaces and shading of buildings. Moreover,various studies and recommendations for solar rights in special cases were suggested byresearchers using different methods and design tools [1–8].In this work we present a systematic study of building design around urban squares inorder to determine how the different proportions of squares and buildings heights aroundthem influence the insolation of the square in winter.The objectives of the work presented in this paper are:1. To develop recommendations and design guidelines to be applied in the early designstages that will provide proper insolation of different urban squares and any other openspaces. We presume that only the number of insolation hours is significant for openspaces. This is in contrast to the requirement of insolated roofs, were solar collectorsfor hot water should be located, or the insolation of the southern elevations, throughwhich passive solar energy for heating the buildings in winter can be achieved. In thelast cases, not only the hours of solar exposure should be calculated, but the exact solarradiation should be considered as well [9].2. Once the recommended proportion of the urban squares is known, the second objectiveis to present the insolated and shading zones during winter and summer in the aboverecommended urban squares. As a result, the exact location of special functions, suchas sitting and playing areas, can be determined. 2. Methodology To achieve the above goals, many different urban squares were examined and the exactarea that is exposed to the sun during the whole year was calculated.The following geometries were considered:1. Proportions of the urban square: W1L1, W1L1.5, W1L2, where W is the width of thesquare and L is its length. The width is taken as 1 unit. The length may take any value,but we assume the following possibilities: 1, 1.5 or 2 units. For example W1L2 meansthat the length of the square is twice its width.2. The cross-section of the urban square and the buildings around (will be denoted by theprofile of the urban square): W1H1, W1H2/3, W1H1/2, W1H1/3, where W is the widthof the urban square and H is the height of the buildings around it. The width is taken as1 unit. The height H may take the values 1, 2/3, 1/2 or 1/3 units. For example W1H1/3  A. Yezioro et al. / Renewable Energy 31 (2006) 1011–1023 1012  Fig. 1. The different proportions and profiles of urban squares that were examined.  A. Yezioro et al. / Renewable Energy 31 (2006) 1011–1023  1013  means that the width of the urban square is three times bigger than the height of thebuildings around it.3. The orientation of the urban square: The long axes of the square may be directed toN-S, E-W, NW-SE or NE-SW.The combination of the proportions and profiles of the urban square is denoted by:W1L2H1/3, which means that the length of the urban square is twice its width and thewidth of it is three times the height of the buildings around the urban square. The casesexamined are presented in Fig. 1.The width and the length of the urban square are defined as the distance between thebuildings around it (including sidewalks etc.). Let’s mention that the buildings in thenorthern part of the urban square will not cast shadows on it. As a consequence, theirheight is not limited, as long as they don’t shade the street, other open spaces or otherbuildings. The decision about their allowed height should be considered according to thefunction of the elements north to it. 3. Visual appraisal The simplest way to figure out the insolated and the shaded areas is by drawing anorthographic projection from the sun’s point of view [7]. The area exposed to the sun is Fig. 2. Visual appraisal of the insolation of the urban square W1L2H2/3 oriented to different directions. The areathat is seen is the insolated part of the urban square at that particular time. At each month and hour fourorientations are presented according to the scheme in the low-left part of this figure.  A. Yezioro et al. / Renewable Energy 31 (2006) 1011–1023 1014  Wi   n t   er   0 1  0 2  0  3  0 4  0  5  0  6  0 7  0  8  0  9  0 1  0  0   NOV 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . DEC 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . JAN 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . FEB 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . MAR 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs .  S  umm er   0 1  0 2  0  3  0 4  0  5  0  6  0 7  0  8  0  9  0 1  0  0   MAY 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . JUNE 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . JULY 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . AUG 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . SEP 6 hrs 7 hrs 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs 15 hrs 16 hrs 17 hrs 18 hrs . H 1  /   3 H 1  /  2 H 1  /  1 . 5 H 1   5 h  o ur  s  av  er  a g ei  n s  ol   a t  i   on-D  e c  em b  er  0 1  0 2  0  3  0 4  0  5  0  6  0 7  0  8  0  9  0 1  0  0  H 1  H 1  /  1 . 5  H 1  /  2  H 1  /   3  S  q u ar  eP r  of  i  l   e % F i     g . 3  .T h  e  GI   C  a n d A GI   C  W of   t  h  e  ur  b  a n s   q u a r  e  W1 L 2  or i    e n t   e  d  N- S f   or  e  a  c h  s   q u a r  e   pr  ofi l    e  (   3 2  8         N or  t  h L  a  t  i    t   u d  e  )   .     A .    Y   e   z  i   o   r   o   e  t   a  l .   /    R   e   n   e    w   a   b  l   e    E   n   e   r   g   y   3   1  (   2   0   0   6  )   1   0   1   1   –   1   0   2   3    1    0   1    5
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks