Earth Architecture - Improving Living Conditions for Rural-Low Income Housing - Self Build With Earth
Short Description
Descripción: Housing is a very important sector having enormous potential for saving energy and carbon emissions. With 3...
Description
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ABSTRACT
Housing is a very important sector having enormous poten al for saving energy and carbon emissions. With 32% of the people below the interna onal poverty line and 70% of the people below a wage of 2$ per day, there is an enormous lack of sound housing in India. Prac ces in recent years is seeing a huge shi from vernacular to the use of modern materials argued on basis of be er durability and be er indoor performance compared to natural materials. This research inves gates the applica on of various natural materials, specifically earth within rural housing. It tries to improve living condi ons in current built form by using passive design strategies, u lising various building simula on tools and knowledge from tradi onal prac ces. It also looks into the benefits of using environmental friendly natural materials to that of conven onal ones. This study was carried out at the Architectural Associa on School of Architecture, London, UK in 2012.
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ACKNOWLEDGEMENT I wish to thank my family for their uncondi onal support during the tenure of this disserta on. I would especially like to thank my tutor, Dr. Rosa Schiano-Phan for providing con nuous guidance and support throughout the process of this study. I would like to thank the course director, Dr. Simos Yannas, for providing integral and valuable insights. Special thanks and acknowledgment to Architect Vasant & Revathi Kamanth and Dhunas Ali for providing and gran ng access to their residence, informa on and literature for the fieldwork studies. I’d like to thank Humberto M. and Jose Luis B. for there insights and for collabora ng during group work. Finally, thanks to my colleagues, friends and all tutors for their valued comments, guidance and reviews towards my research study.
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TABLE OF CONTENTS CHAPTER 1 1_SCENARIO……………………………………………………………………………………………………………….……………………
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1.1
Introduc on…………………………………………………………………………………………………………………………..
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1.2
Popula on below the Poverty Line………………………………………………………………………………………..
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1.3
Rural Living Condi ons………………………………………………………………………………………………………….
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1.4
Current Approach to Housing………………………………………………………………………………………………..
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1.5
Classifica on of Houses…………………………………………………………………………………………………………
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1.6
Housing Shortage………………………………………………………………………………………………………………….
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1.7
‘INDIRA AWAAS YOJNA’…………………………………………………………………………………………………………
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1.8
Shi from ‘Kutcha’ to ‘Pakka’………………………………………………………………………………………………..
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1.9
Conclusion…………………………………………………………………………………………………………………………….
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CHAPTER 2 2_ NATURAL MATERIALS………………………………………………………………………………………………………………
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2.1
Environmental Impacts of Conven onal Materials………………………………………………………………..
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2.2
Life Cycle of Materials……………………………………………………………………………………………………………
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2.3
Embodied Energy and Embodied Carbon……………………………………………………………………………..
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2.4
Embodied Energy and Carbon Assessment…………………………………………………………………………...
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2.5
Thermal Performance……………………………………………………………………………………………………………
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2.6
Thermal Capacity…………………………………………………………………………………………………………………..
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2.7
Environmental Impact of Building Tech. in Kutch Distrct, Gujrat, India (NW region of India)...
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2.8
Conclusion…………………………………………………………………………………………………………………………….
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CHAPTER 3 3_CLIMATE ANALYSIS…………………………………………………………………………………………………………………..
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3.1
Clima c Zone and Loca on……………………………………………………………………………………………………
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3.2
Temperature and Season Varia ons………………………………………………………………………………………
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3.3
Wind Studies…………………………………………………………………………………………………………………………
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3.4
Ven la ve Cooling………………………………………………………………………………………………………………..
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3.5
Global Horizontal Radia on…………………………………………………………………………………………………..
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3.6
Temporal Distribu on of Global Horizontal Irradiance and Solar Bins…………………………………..
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3.7
Daylight Hours in a Year…………………………………………………………………………………………………………
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3.8
Ligh ng Levels………………………………………………………………………………………………………………………
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3.9
Temperature Swings……………………………………………………………………………………………………………..
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3.10
Ground Temperature…………………………………………………………………………………………………………….
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CHAPTER 4 4_COMFORT ZONE AND MEANS TO ACHIEVE IT PASSIVELY…………………………………………………………
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4.1
Comfort Band………………………………………………………………………………………………………………………..
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4.2
Shading………………………………………………………………………………………………………………………………….
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4.3
Thermal Mass………………………………………………………………………………………………………………………..
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4.4
Night Time Ven la on……………………………………………………………………………………………………………
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4.5
Physiological Cooling………………………………………………………………………………………………………………
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4.6
Evapora ve Cooling…………………………………………………………………………………………………..…………..
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4.7
Dynamic Earth Contact Building: Poten al Heat Sink .……………………………………………………………
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4.8
Cooled Soil as a Cooling Source……………………………………………………………………………………………..
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CHAPTER 5 5_PRECEDENT………………………………………………………………………………………………………………………………..
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5.1
Genesis Centre………………………………………………………………………………………………………………………
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5.2
Courtyard House……………………………………………………………………………………………………………………
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CHAPTER 6 6_FIELDWORK…………………………………………………………………………………………………………………………….….
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6.1
CAT-WISE Auditorium……………………………………………………………………………………………………………
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6.2
Kamath House……………………………………………………………………………………………………………………….
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6.3
‘BHUNGA’ Architecture………………………………………………………………………………………………………….
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CHAPTER 7 7_ANALYTICAL WORK…………………………………………………………………………………………………………...………
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7.1
Introduc on…………………………………………………………………………………………………………………………..
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7.2
Flow Chart……………………………………………………………………………………………………………………………..
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7.3
Basic Principles Applied to Design and for Modelling in TAS for NW Region of India…………….
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7.4
Model Inputs…………………………………………………………………………………………………………………………
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7.5
Vernacular VS New CSEB Structures………………………………………………………………………………………
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7.6
Interven ons…………………………………………………………………………………………………………………………
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CHAPTER 8 8_CONCLUSION AND FUTURE RESEARCH...…………………………………………………………………………………..
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8.1
Conclusion...…………………………………………………………………………………………………………………………..
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8.2
Future Research……………………………………………………………………………………………………………………..
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REFERENCES & BIBLIOGRAPHY………………………………………………………………………………………………………
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APPENDIX………………………………………………………………………………………………………………………………………
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Appendix A_ Natural Materials……………………………………………………………………………………………………….……
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Appendix B_Clima c Analysis……………………………………………………………………………………………………….………
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Appendix C_Comfort Zone and Means to achieve it passively…………………………………………………….………..
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Appendix D_Fieldwork…………………………………………………………………………………………………………….…………..
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Appendix E_Analy cal Work………………………………………………………………………………………………….…………….
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LIST OF FIGURES Figure 1.1_ Figure 1.2_ Poverty Headcount $1.25 & $2 per day Figure 1.3_ Percentage popula on living on less than $1.25/day Figure 1.4_ World distribu on of earth architecture. Figure 1.5_ Rural Rajasthan Family House Figure 1.6_ Structure in ‘Khuri’ Village Figure 1.7_ Cluster of houses in Rajasthan Figure 1.8_ Temporary ‘kutcha’ house Figure 1.9_ Embodied energy in various types of wall construc on materials. Figure 1.10_ Carbon emissions of various types of wall construc on materials.
Figure 2.1_ Figure 2.2_ World per capita produc on of steel and cement. Figure 2.3_ Carbon emissions of various types of bricks/blocks. Figure 2.4_ Materials life-cycle and emissions. Figure 2.5_ Industries distribu on schemes. Figure 2.6_ Typical life carbon. Figure 2.7_ Contemporary scenarios of opera onal and embodied carbon according to use. Figure 2.8_ Future scenarios of opera onal and embodied carbon according to use. Figure 2.9_ Embodied carbon and energy—cradle to gate. Figure 2.10_ Compara ve graph of U-values based on average densi es and wall thickness. Figure 2.11_ Compara ve graph showing thermal capacity for different materials. Figure 2.12_ Graph Showing Total Energy consump on for const. and maintenance for different building technology. Kutch District, Gujrat, India. Figure 2.13_ Graph Showing Total NRE and RE including transporta on for different building technology. Kutch District, Gujrat, India. Figure 2.14_ Graph Showing CO2 emissions for construc on and maintenance including transport for different building technology. Kutch District, Gujrat, India. Figure 2.15_ Graph Showing Water Consump on in lt/m2 for different building technology. Kutch District, Gujrat, India. Figure 2.16_ Rammed earth process
Figure 3.1_World Climate Map Figure 3.2_ Loca on of India Figure 3.3_ Clima c Zones in India Figure 3.4_ Graphical representa on of the monthly average temperature range with dis nct seasonal classifica on. Figure 3.5_ Rela ve Humidity Figure 3.6_ Year round hours and direc on of prevailing winds Figure 3.7_ Hours and Direc on of winds Figure 3.8_ Monthly Wind Speeds Figure 3.9_ January Winds
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Figure 3.10_ August Winds Figure 3.11_ Monthly Global Horizontal Radia on and Cloud Cover Figure 3.12_ Solar Radia on Frequency (Upper) & Temporal distribu on (Lower) Figure 3.13_ Daily daylight hours Figure 3.14_ Daylight availability curve Figure 3.15_ Monthly min/mean/max temperature swings Figure 3.16_ Ground temp. at 1m and 4m depth.
Figure 4.1_ Graph showing yearly clima c condi ons overlaid with the adap ve comfort band Figure 4.2_ Graph showing yearly clima c condi ons overlaid with the adap ve comfort band and strategies. Figure 4.3_ Graph showing the Average Daily Incident Solar Radia on (Wh/m²) for all orienta ons for New Delhi Figure 4.4_ Different earth-structure configura ons with different boundary interfaces Figure 4.5_ DBT and soil temperatures of the treated (bo om) & untreated soil Figure 4.6_ A layer of gravel blocks solar radia on away from the soil surface and reduces convec ve exchange.
Figure 5.1_ Genesis centre entrance Figure 5.2_ Earth Pavilion interior (Genesis Centre) Figure 5.3_ Straw Pavilion (Genesis Centre) Figure 5.4_ Glass Pavilion (Genesis Centre) Figure 5.5_ Timber Pavilion (Genesis Centre) Figure 5.6_ Clay Pavilion (Genesis Centre) Figure 5.7_ Schema c plan of the Genesis Centre in Somerset Figure 5.8_ Schema c Plan of the Genesis Centre highligh ng the earth pavilion. Figure 5.9_ Rammed earth wall under construc on. (Genesis Centre) Figure 5.10_ Cob blocks used on site (Genesis Centre) Figure 5.11_ Massed cob wall under construc on (Genesis Centre) Figure 5.13_ Earth Pavilion—Floor Plan (Genesis Centre) Figure 5.14_ Earth Pavilion—Roof Plan. (Genesis Centre) Figure 5.15_ Rubble Roof (Genesis Centre) Figure 5.15_ Rubble Roof (Genesis Centre) Figure 5.16_ Rammed earth walls under construc on. (Genesis Centre) Figure 5.17_ External Insula on: Wood waste Fibreboards (Genesis Centre) Figure 5.18_ Detail of Glass Pavilion roof mee ng Earth Pavilion and Ven la on slots (Genesis Centre) Figure 5.19_ Connec on between the roof and the cob wall. (Genesis Centre) Figure 5.20_ Street façade of the courtyard house Figure 5.21_ Courtyard residen al Units (Courtyard House) Figure 5.22_ Courtyard house Interior (Courtyard House) Figure 5.23_ Cooling Tower on West walls (Courtyard House) Figure 5.24_ Transparent Roof on South (Courtyard House)
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Figure 6.1_ Cat-wise premises Figure 6.2_ Centre of alterna ve technologies, Wales Ins tute of Sustainable Educa on Figure 6.3_ General Plan of Cat-Wise Figure 6.4_ Sec on showing the buffer spaces and the interior of auditorium Figure 6.5_ Sec on showing different loca on of the sensors Figure 6.6_ Recorded temperatures and humidity on 25th and 26th of May Figure 6.7_ Spot Measurements taken on 245th and 26th of May Figure 6.8_ Recorded temperatures from the installed sensors on South Wall Figure 6.9_ Recorded temperatures from the installed sensors on North wall Figure 6.10_ Upper Floor Living Room—Kamath House Figure 6.11_ Main entrance to house (Kamath House) Figure 6.12_ North east façade (Kamath House) Figure 6.13_ Upper living room (Kamath House) Figure 6.14_ Lower living room (Kamath House) Figure 6.15_ Images showing adobe and stone const. (Kamath House) Figure 6.16_ Courtyard near lower living cum dining (Kamath House) Figure 6.17_ Misters installed in the courtyard provide evapora ve cooling. (Kamath House) Figure 6.18_ Images showing openings in upper Living and staircase spaces (Kamath House) Figure 6.19_ Green roof supported on bamboo—Crete and rough wood. (Kamath House) Figure 6.20_ Sketch showing cross ven la on through the house. Small openings at various levels reduce thermal stra fica on. (Kamath House) Figure 6.21_ Sketch showing sec on of house with various techniques and strategies incorporated into the hands of design of the house (Kamath House) Figure 6.22_ Upper floor plan (Kamath House) Figure 6.23_ Lower floor plan. (Kamath House) Figure 6.24_ Posi on of data logger in Upper living room (Kamath House) Figure 6.25_ Posi on of data logger in Lower living room (Kamath House) Figure 6.26_ Posi on of data logger in Bed room (Kamath House) Figure 6.28_ Graph showing temperature and rela ve humidity readings in the upper living room. (Kamath House) Figure 6.29_ Graph showing temperature and rela ve humidity readings in the lower living room. (Kamath House) Figure 6.30_ Graph showing temperature and rela ve humidity readings in the master bedroom. (Kamath House) Figure 6.31_ Graph showing surface temperature measurements of the inner surface of an adobe wall oriented south
west. (Kamath House)
Figure 6.32_ Graph showing spot measurement in various places of the house on 16th July’12. (Kamath House) Figure 6.33_ Graph showing spot measurement in various places of the house on 16th July’12. (Kamath House) Figure 6.34_ Sketch showing indoor surface temperature measurements in the Upper Living Room. (Kamath House) Figure 6.35_ Stone Slates in Kamath House Figure 6.36_ Graph showing spot surface temperature measurements of stone slate—covering roof surface taken on 16th July’12. (Kamath House)
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Figure 6.37_ Stone wall in Kamath House Figure 6.38_ Graph showing spot surface temperature measurement of stone wall taken on 16th July’12. Figure 6.39_ Tradi onal ‘Bhunga’ in Kutch region of Gujrat. NW region of India. Figure 6.40_ Typical Vernacular ‘bhunga.’ Figure 6.41_ Centre of 2001 Earthquake—Bhuj. Figure 6.42_ Damage to conven onal structures. (Bhunga) Figure 6.43_ Plan and Eleva on view of a typical ‘Bhunga’ showing key details (With wooden post). Figure 6.44_ Circular and rectangular house under Construc on in 2001 Figure 6.45_ Completed structures built by NGO’s and the government. Figure 6.46_ House that was measured. Author (in green) with the occupant of the house (in purple). (Bhunga) Figure 6.47_ Window opening in Bhunga Figure 6.48_ Pyramidal roof structure of the Bhunga Figure 6.49_ New CSEB house adjacent to the vernacular bhunga Figure 6.50_ Graph showing spot temperature and rela ve humidity readings of the (Bhunga) Figure 7.1_ Flowchart of Analy c Work Figure 7.2_ Flowchart of the methodology followed for analytic work. Figure 7.3_ Sketch showing orienta on and built form incorporated in design and for modeling in EDSL TAS. Figure 7.4_ Sketch showing roof form incorporated in design and for modeling in EDSL TAS. Figure 7.5_ Sketch showing advantage of using pitched flat roof and different ground covering. Figure 7.5a_ Sketch showing how vegeta on can help in aiding ven la on by direc ng and increasing wind speeds. Figure 7.6_ Housewife waiting for her husband to return from farm, Rajasthan. Figure 7.7_ Housewives with their children during the day. Gujrat. Figure 7.8_ Schedules of various member of this type of housing. Figure 7.9_ Average occupancy pattern Figure 7.10_ Vernacular structure Figure 7.11_ Modern CSEB structure Figure 7.12_ TAS graph of a typical summer week comparing performance of vernacular structure to that of new built CSEB structures. Figure 7.13_ TAS graph of a typical monsoon week comparing performance of vernacular structure to that of new built CSEB structures. Figure 7.14_ Graph showing temp. above comfort band in vernacular and CSEB structures. Figure 7.15_ Elevation and section showing change n window opening with out to with glazing Figure 7.16_ Graph showing effect on indoor temp. due to the application of glazed shutters to openings with a NTV schedule. (MS) Figure 7.17_ Graph showing effect on indoor temp. due to the application of glazed shutters to openings with a NTV schedule (MS). Figure 7.18_ Elevation and Section showing change in door opening without to with 0.5% opening Figure 7.19_ Graph showing effect on indoor temp. due to opening doors for night time ventilation. (SS)
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Figure 7.20_ Graph showing effect on indoor temp. due to opening doors for night time ventilation. (MS) Figure 7.21_ Addition of insulation on the lower part of the roof Figure 7.22_ Graph showing effect on indoor temperatures due to insulating the roof. (SS) Figure 7.23_ Graph showing effect on indoor temperatures due to insulating the roof. (MS) Figure 7.24_ Elevation and Section showing change in window size Figure 7.25_ Daylight distribution within the space with different window to floor ratio.. Figure 7.26_ Graph showing effect on indoor temperatures due to increased window size (WFR—original 2%, increased to 10%). (SS) Figure 7.27_ Graph showing effect on indoor temperatures due to increased window size (WFR—original 2%, increased to 10%). (MS) Figure 7.28_ Graph showing effect on indoor temperatures due to addition of small openings. (SS) Figure 7.29_ Graph showing effect on indoor temperatures due to addi on of small openings. (MS) Figure 7.30_ Section showing opening in the roof Figure 7.31_ Graph showing the effect on indoor temp. due to provision of an opening on top of roof. (SS) Figure 7.32_ Graph showing the effect on indoor temp. due to provision of an opening on top of roof. (MS) Figure 7.33_ Increase of Albedo values on wall and roof surfaces. Figure 7.34_ Graph showing the effect of using high albedo paints on the surface of the building. (SS) Figure 7.35_ Graph showing the effect of using high albedo paints on the surface of the building. (MS) Figure 7.36_ Earth Sheltering Figure 7.37_ Graph showing effect of earth sheltering on indoor temperatures. (SS) Figure 7.38_ Graph showing effect of earth sheltering on indoor temperatures. (MS) Figure 7.39_ Roof Scenarios Figure 7.40_ Graph comparing effect of different roof configurations on indoor temperatures (SS). Figure 7.41_ Graph comparing effect of different roof configurations on indoor temperatures (MS). Figure 7.42_ Graph showing total no. of hours the temp. is above 33°C in two seasons. Figure 7.43_ Graph showing total no. of hours the temp. is above 33°C in the two seasons during day & night. Figure 7.44_ Graph showing effect of cumulative effect of interventions on indoor temperatures compared to vernacular and new built present situation. Also plotted are WBT and Tpdec temperatures. (SS)
Figure 7.45_ Graph showing cumulative effect of interventions on indoor temperatures compared to vernacular and new built present situation. (MS)
Figure 7.46: Sketch showing occupant watering the surrounding area of the house early in the morning in summer season. Figure 7.47_ Sketch showing strategies applied during day me in summer and monsoon season to reduce indoor temperature rise. Figure 7.48_ Sketch showing strategies applied during late evening and night hours to reduce indoor temperature during summer and monsoon season
Figure 7.49_ Sketch showing solar gain indoors during winter season. Openings are closed to retain heat during evening and night hours.
Figure 8.1_Image showing India has medium to high vulnerability to climate change.
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LIST OF TABLES Table 1_ Rural and Urban Popula on, India Table 2_ Classifica on of different types of housing according to 2001 Census Table 3_ Es mated Shortage of Housing in India Table 4_ Construc on assistance provided under Indira Awaas Yojna (IAY) Table 5_ Graph of local and conven onal materials comparing various characteris cs of the material. Table 6_ Weather readings for New Delhi Table 7_ Group Wise regression analysis for Neutral Temperatures Table 8_ Morning and A ernoon RH (%) Table 9_ Average wind speed during the Day and night. Table 10_ Temperature gradient for different earth sheltered structure Table 11_ Heat flux across floors in different earth sheltered structures. Table 12_ Physical characteris cs of different earth construc ons Table 13_ Cost of construc ng circular rammed earth structure at Hastkala Nagar, Kutch, Gujrat, India. Table 14_ Cost of construc ng rectangular rammed earth structure at Hastkala Nagar, Kutch, Gujrat, India. Table 15_ Sensible heat gain in the structure.
Table 16_ Specifica ons of materials used in EDSL TAS Model. Table 17_ Morning and A ernoon RH (%)
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APPENDIX
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APPENDIX A NATURAL MATERIALS Earth: a stable, dense, non-vola le inorganic substance found in the ground. (The New Oxford Dic onary of English, 1998) Masonry: the art of shaping, arranging and uni ng stone, brick, building blocks, etc, to form walls and other parts of a building. (Dic onary of Architecture and Construc on, 1975) Earth buildings have been very popular and prevalent worldwide with a third of the worlds popula on living in earth buildings. Also 20% of UNESCO world heritage sites were constructed from unfired earth. Structures like the Great Wall of China [Fig. A.1], Friday Mosque in Mali [Fig. A.2] and buildings in Taos Pueblo - are the oldest, con nuously inhabited structures, are all constructed of earth. There are many good reasons to use earth masonry. Apart from being a naturally abundant material, it is environmentally sustainable, cheap, requires low maintenance, provides thermal stability compared to its counterparts and is a good moderator of humidity. Zami compiled a list of advantages of using earth which were published by different authors [Table T1].
Figure A.1: Great wall of china mainly made out of earth masonry, albeit clad with stone at its eastern end Source: Morton, T. 2008
“The ideal building material would be ‘borrowed’ from the environment and replaced a er use. There would be li le or no processing of the raw material and all the energy inputs would be directly, or indirectly, from the sun. This ideal material would also be cheap. Mud bricks can come close to this ideal. “ Paul Dowton ADOBE Adobe is generally prepared worldwide by mixing earth with water and placing the mixture into moulds. A er ini al drying in outdoor air, it is removed from the moulds and allowed to dry in direct sun. The drying process can last from a week to 3 weeks depending upon clima c condions. The first earth bricks were hand moulded and dried in the sun in the Neolithic era. They were at mes mixed with straw and animal dung to create a stronger bond however, a well dried mud-brick can provide sufficient strength for a 1-2 storey structures.
Figure A.2: 19th century Friday Mosque, Djenne, Mali; with grain stores and houses in front, all built of earth masonry. Source: Morton, T. 2008
Contemporary earth construc on exists in two formats which includes un-stabilized and stabilized earth construc on. In stabilized earth construc on, earth is usually mixed with stabilizers to enhance their potenals such as compressive strength, water resistance, etc. Some of these stabilizers are natural - rice husk, straw, bagasse, etc. leading to the creaon of adobe bricks containing agricultural by-products with improved strength and lower moisture absorp on. This is an environmentally sound and sustainable prac ce resul ng in low embodied energy and very low to zero carbon emission products. On the other hand, builders world over have experimented with man-made products such as flyash, bitumen, emulsion, portland cement and a combina on of these materials to create a stronger by-product. According to King, the strongest binder amongst all these is found to be
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Table T1 : Table showing advantages of using earth.
Earth Advantages
Authors
Earth construc on is economically beneficial.
Lal, 1995; Easton, 1996; Minke, 2006; Zami & Lee, 2007; Morton, 2007; Kateregga et al, 1983; Cassell, 1993; Walker et al, 2005; Hadjri et al, 2007; Morris and Booysen, 2000; Adam and Agib, 2001, p11;
It requires simple tools and less skilled labour.
Kateregga, 1983; Easton, 1996; Minke, 2006, p15; Hadjri et al, 2007; Morris and Booysen, 2000; Adam and Agib, 2001, p11; Maini, 2005;
It encourages self‐help construc on
Kateregga, 1983; Minke, 2006, p15;
Suitable for very strong and secured structure
Lal, 1995, p119; Houben & Guillaud, 1989; Walker et al, 2005;
It saves energy
Morton, 2007; Lal, 1995, p119; Minke, 2006; Hadjri et al, 2007; Adam and Agib, 2001, p11; Maini, 2005;
Cassell, 1993; Howieson, 2005; Alphonse et al, 1985; Minke, 2006; It balances and improves indoor air humidity and Kateregga et al, 1983; Lal (1995, p119); Walker et al, 2005; Hadjri et temperature which ensures thermal comfort. al, 2007; Adam and Agib, 2001, p11;
Earth is very good in fire resistance
Earth construc on is regarded as a local job crea‐ Adam and Agib, 2001, p11; Morel et al, 2001; on opportunity.
Minke, 2006; Easton, 1998; Walker et al, 2005; Hadjri et al, 2007; Earth construc on is environmentally sustaina‐ Adam and Agib, 2001, p11; Maini, 2005; Ngowai, 2000. Reddy, 2007, ble. p194; Morel et al, 2001;
Loam preserves mber and other organic materi‐ Minke, 2006, p15; (Mohler 1978, p. 18). als.
Earth wall (loam) absorbs pollutants.
Cassell, 1993; Minke, 2006;
Easy to design and high aesthe cal value
Morton, 2007; Houben & Guillaud, 1989; Walker et al, 2005; Hadjri et al, 2007.
Earth building provides noise control
Kateregga, 1983; Alphonse et al, 1985; Hadjri et al, 2007;
Earth construc on promotes local culture and Frescura, 1981. heritage.
Earth is readily available in large quan most region.
Alphonse et al, 1985; Walker et al, 2005, p43; Hadjri et al, 2007; Adam and Agib, 2001, p11;
es in Adam and Agib, 2001, p11; Easton, 1996; Lal, 1995; Hadjri et al, 2007; Morris and Booysen, 2000; Adam and Agib, 2001, p11;
Source: Compiled by Zami et al. - Contemporary Earth Construc on in Urban Housing—Stabilised or Unstabilised (2010).
portland Cement (King, B. 1996). Prac ce includes mixing earth with 5—8% of Portland cement resul ng in the crea on of Cement Stabilised Earth Blocks (CSEB). In comparison to kiln fired bricks, CSEB provides carbon and energy savings and are more durable and strong compared to adobe however, cannot be returned to earth at the end of a buildings life cycle.
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Adding cement not only reduces earth’s inherent proper es to act as a temperature and humidity regulator but its produc on is labour intensive and requires professional guidance for appropriate soil selec on and proporon of cement to be added to it. Therefore the predicament lies in a debate between choosing stabilized and un-stabilized earth masonry. Even though CSEB offers a low energy alterna ve to kiln fried bricks, its accessibility to the rural/urban poor is far from sa sfactory. According to Jagdish (2007), stabilized earth construc on is less expensive than brick masonry, however it is s ll expensive than what the poor can afford. Moreover, its suitability for self-build by uneducated, poor individuals in developing countries is of major concern and cannot be taken for granted. However, one cannot overlook the increased strength a stabilized earth block provides. This is the view of the author that by using natural stabilizers which do not reduce the inherent proper es of adobe significantly, is the way forward. In the north west region of India, the rural poor are involved mainly in farming or have access to families involved in farming. Therefore obtaining rice husk, bagasse or straw would not only be easier but to use it as stabilizer will be environmentally friendly compared to Portland cement. Research carried out by Lertwa anaruk et al. (2011) concludes on the benefits of using natural stabilizers such as rice husk and bagasse. Lertwa anaruk found that the use improved the compressive strength of adobe [Fig A.3], reduced shrinkage and thermal conduc vity. In addi on it reduced moisture accumula on in comparison to concrete and when subject to loading– adobe stabilized with bagasse eroded less in comparison to the rest of the test products. Current prac ces in the villages of developing na ons where selfbuild is the primary mode of construc on by the poor, emphasis on the standards for construc on are very li le to none. In order to make adobe qualify for use as soil block for construc on in India, IS 1725 states that it should have a minimum compressive strength of 20 kg/cm². By mixing adobe with 1% bagasse and above or 3% rice husk, these standards can be met [Fig A.3]
80.00 Compressive Strength (Kg/cm²)
Rice Husk
Bagasse
70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00
Adobe 0% Fiber
Adobe + 1% Fiber
Adobe + 2% Fiber
Adobe + 3% Fiber
Adobe + CSEB (5‐10% cement) 6% Fiber
Masonry Brick
Minimum required compressive strength for class 20 bricks. [Source: Indian Standard — Specifica on for soil based blocks used in Concrete general building construc on (IS 1725)]
Figure A.3: Compressive strength of adobe containing rice husk and bagasse. Source: A er Lertwa anaruk et al. (2011)
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2.8 ADOBE VS RAMMED EARTH
Adobe and rammed earth are both borne from the earth and their pracces have existed since ancient mes. One involves making bricks in moulds whereas the later involves compac ng moist sub soil inside formworks by using metal or wooden rammers.[ Fig A.4]
Figure A.4: Rammed earth process Source: h p://bartle year1architecture.blogspot.co.uk/2010/02/rammed-earth-construc on.html
Rammed earth requires tools such as those required to assemble and disassemble the formwork, compac on of earth using rammers, etc. The soil is compressed and would require greater strength to create niches for electrical ducts, lights and sanitary hardware. On the other hand, Adobe has lower embodied energy and carbon as compared to rammed earth. It needs no technical knowledge, requires no specialized tools and no formwork for its produc on and can be easily managed and moved about. Crea ng niches and making altera ons to the structure is much easier than rammed earth. Hence, the use of adobe seems appropriate when tools and technical knowledge to produce rammed earth are not available.
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HEMP‐LIME AS CONSTRUCTION MATERIAL
Along history many vegetal fibers have been used as construcon materials. For instance, in many countries around the world straw and linen fibers are used to lighten concrete and improve its performance1. Hemp-lime is one example of this building technique. Hemplime is the combina on of hemp fibers, lime based binder and water. This mixture forms a solid composite material that can be used in a wide variety of elements in construc on2. This material is referred by its generic name of hempcrete.
Figure A.5: Simula on internal temperature con-
The use of hemp hurd has some environmental benefits. First, hemp plant has a very fast growth rate. For example, 30,000 tonnes of hemp have been harvested in 2003, and this number has been duplicated in 2005. Also, due to its fast growth rate hemp plant can adapt easily to most clima c condi ons what is beneficial for agricultural purposes. Furthermore, hemp plant could grow organically. Compara vely to other fibers like co on could spend up to 7.4 millon US dollars per year in pescides for its cul va on3. Finally, the most important environmental benefit of hemp plant is it CO2 sequestra on during its cul va on period. It has been said that every cubic meter of hemp-lime sequestrate 110 kg of CO2. Hemp-lime materials have also significant thermal performance advantages. A er simula ons shown in literature, it has been said that hemplime construc on has important insula on proper es, and it regulates extreme indoor temperature varia ons. For instance, in some cases U values of 0.3 W/m²K in walls have been achieved4.
Figure A.6: BRE Renewable house / innova on
However, the thermal proper es of hemp-lime materials have been tested in dry condi ons within laboratory environments. Further studies, using specialized so ware for dynamic simula ons, have proved that moisture content could affect its thermal proper es. For example, a raise in the rela ve humidity of the material also increases its thermal conduc vity. This issue also helps the material to regulate the internal rela ve humidity with beneficial improvement in air quality for the occupants. Using this material, indoor rela ve humidity could remain within the range of 40 to 60%.5
This material and its precedent study is adapted from the report—Local Techniques submi ed in May’12 at the AA school. It was produced by the author and his peers. Source: Barros, J.L. et al . (2012). Local Techniques. AA School 1
Evrard A.(2008). Transient hygrothermal behaviour of Lime-Hemp Materials Evrard A.(2008). Transient hygrothermal behaviour of Lime-Hemp Materials 3 Bevan R and Wolley T (2008). Hemp lime construc on guide to build with hemp lime composites 4 Bevan R and Wolley T (2008). Hemp lime construc on guide to build with hemp lime composites 5 Bevan R and Wolley T (2008). Hemp lime construc on guide to build with hemp lime composites 2
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BUILT PRECEDENTS ‐ BRE’S RENEWABLE HOUSE [Fig. A.7] The main objec ve of this project was to achieve a low cost and low carbon by using alterna ve building techniques without compromising the affordability. The house is labelled as sustainable house code 4, and its developers claimed that its cost is around £75,000. However, the design of the house enables enhancement to meet Level 5 and 66. The brief provides a 3 bedroom detached house built en rely on hempcrete with mber frame structure. Built in only 12 weeks, the construc on contemplates key factors as triple glassed windows and renewable insula on materials in order to achieve the code 4. The appropriate construc on with these materials prevents innecesary heat losses through minimizing the thermal bridges in the joints Figure A.7: BRE Renewable house / innova on [Fig: A.8]. The visit to the project shows the few thermal bridges through the building envelop. Finally, the house is very thermal efficient, by using the proper es of the materials and reducing the thermal bridging the energy consumpon is very low. Nevertheless, it uses hea ng system is basically provided by heat pumps and air recovery systems7. In many aspects the house could be an interes ng built precedent for further developments.
Figure A.8: Thermal picture to show the heat losses through the building envelope
This material and its precedent study is adapted from the report—Local Techniques submi ed in May’12 at the AA school. It was produced by the author and his peers. Source: Barros, J.L. et al . (2012). Local Techniques. AA School 6
h p://www.renewable-house.co.uk/news/2/ - BRE renewable house website
7
h p://www.renewable-house.co.uk/news/2/ - BRE renewable house website
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STRAW BALE Oil and fossil fuels have powered the developed na ons for the past 150 years resul ng in an enormous release of greenhouse gases. Earth’s climate is changing and carbon emissions must be reduced. As building regula ons go forward with regula ons to curb opera onal energy in buildings, their embodied energy and embodied carbon becomes a big concern. Using natural renewable materials which sequesters carbon during their growth and lock it in the buildings’ fabric is beneficial from both embodied carbon and embodied energy point of view. Straw is a renewable material offering much lower embodied energy impact than many current mainstream materials. It is very suitable for infill insula on in lightweight structures with render on either side. It provides a vapour permeable construc on, however careful detailing and construc on needs to be done to avoid the ingress and retenon of moisture. In-situ construc on as well as prefabrica on can be done with this material. Straw consists of dried dead stems of cereal grains such as rice, wheat, oats, barley, rye, spelt, flax etc, a er they have been harvested. Straw itself is the plant structure between the root crown and the grain head. Bales can also be made from other fibrous materials such as bean or corn stalks, pine needles, or any kind of grass (TLS, 1994:5). Chemically, straw is composed mainly of cellulose, hemicellulose and lignin – very similar to wood, yet contains higher amounts of silica (Eisenberg, 1998). Many of the first bale buildings were constructed from what was abundantly available within the local area: baled meadow or prairie grass (Marks, L.R., 2005) According to the research done by Carol Atkinson (Energy Assessment of Straw Bale Buildings, 2008) straw bale buildings were first constructed in the late 1800’s in the USA as a result of the invent of the baling machines (Jones, 2002). A remake of an early 19th century home can be seen in Figure: A.9. The oldest bale house s ll standing in the Nebraska plains was built in 1903 (King, 2006) and the oldest European straw bale house was built in France in 1921 (Steen, 2000). The first straw bale building in the UK was built in 1994 and there are now over fi y of them18. One of the latest buildings built with straw bale is the Sworders’ auc on rooms, Essex, 2008 [Fig: A.10]
Figure A.9: Re-make of an early 19th century strawbale home. Now an exhibit at a historical tourist a rac on, which informs its visitors of the lifestyles, homes, and work of the era’s homesteaders.
Figure A.10: Sworders’ auc on rooms, Stansted Moun itchet, Essex – a single-storey 1100 m² building, constructed in 2008 using straw bale wall construc on. Source: BRE publica on: Straw Bale
This material and its precedent study is adapted from the report—Local Techniques submi ed in May’12 at the AA school. It was produced by the author and his peers. Source: Barros, J.L. et al . (2012). Local Techniques. AA School
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Figure A.11: Thermal fly wheel of SMS (Spar Membrane System) wall. Source: h p://www.integratedstructures.com/sms/sustainability.html
ADVANTAGES AND DISADVANTAGES OF STRAWBALE AS BUILDING MATERIAL ADVANTAGES
Avoids thermal bridging and provides good air ghtness with simple detailing.
Good insula on quali es
Lightweight material with simple construc on details and processes.
Light weight reduces load on founda ons, reducing the need for materials with high embodied energy (eg concrete)
Low-cost renewable material, widely available from local sources, that stores carbon throughout its life.
Simple building skills suited to self-build and community projects
Suitable for in situ and prefabricated approaches
Vapour-permeable construc on envelope
DISADVANTAGES
As an agricultural co-product, inconsistent proper es (eg dimensions, density and moisture content) can be problema c during construc on.
Details restricted by need to protect the straw from water ingress; careful detailing needed for exposed areas
Limited to rela vely lightweight fixings
Limited water resilience (giving rise to concerns over flood damage) and problems for repair if water damaged (especially loadbearing walls).
Requires shelter before finishes can be applied
Suitability of rendered external finishes limits applica on in some areas
Use limited to above damp-proof course or equivalent level
TYPICAL PROPERTIES OF STRAW BALE
Minimum recommended bale dry density: 110-130 kg/m³
Thermal conduc vity: 0.055-0.065 W/mK (density 110 -130 kg/m³)
Recommended ini al moisture content: 10-16%
Recommended maximum in-service moisture content: normally not to exceed 20-25%. 138
BUILT PRECEDENT ‐ STRAW BALE CABIN EAST YORKSHIRE
Construc on – June 2006 to March 2007
Temperature and rela ve humidity monitoring – February 2007— January 2008
Conduc vity of Straw Bale: 0.06 W/mK
U – value of Wall: 0.123 W/m²K
Temperature inside the straw bale cabin is greatly dampened compared to outside diurnal temp. swings [Fig: A.15]. However, it is not clear whether this is due to:
A high level of insula on
Very thick walls (525mm),
Thermal Mass (25mm) provided by clay plaster
A combina on of all of the above
Figure A.12: Plan (Dimension 4m x 10m)
Lime Plaster on the Cabin’s exterior has a high volume specific heat capacity [Fig. A.13]. It helps to keep the building cool in summer by absorbing heat during the day then releasing it to the cool night air.
Figure A.16: Graph showing energy embodied in the walls of the Straw Bale Cabin and the energy that would have been embodied if the walls had been made of conven onal products.
Figure A.13: A cross sec on through the completed straw bale wall (not to scale). Table T2: Energy embodied in the straw walls of the Straw Bale Cabin
Rela ve humidity between 40-70% is good for the human health as humidity level below or above accelerates bacteria in the air, mould growth, etc. (Minke, G., 2009). Clay plaster on straw bale walls (inside) appears to regulate indoor humidity levels to provide a healthy indoor environment [Fig. A.14]
Figure A.14: Rela ve humidity recorded at the Straw Bale Cabin between 11:25am on 21st September 2007 and the same me on 21st December 2007.
Figure A.15: Temperature inside the unoccupied Straw Bale Cabin (blue line) and outside the Cabin (pink line) on 8th and 9th August 2007
DATA From: Atkinson, C. 2008. Energy Assessment of a Straw Bale Building. University of East London.
Figure A.18: Graph showing energy embodied in the walls of the Straw Bale Cabin and the energy that would have been embodied if the walls had been made of conven onal products.
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5.3 THE RAUCH HOUSE [Fig. A.21] The house is located in Central Europe in a village called the Shlins, Austria. The dwelling is made up of three storeys - the two upper floors are the living rooms and bedrooms whilst the ground floor is the entrance and storage rooms respec vely. It is mainly built by using earthen techniques for the walls, floors, roofs and plastering whilst the furniture’s and finishes are made up of clay and earth materials. ENVIRONMENTAL FEATURES Embodied energy of the house was significantly reduced by using Figure A.21: Rauch House Source: Mar n Rauch natural materials. Furthermore, the preven on from using plas c, silicones or synthe c addi ves was to avoid any indoor air pollu on.
Figure A.22: Rauch House Source: Mar n Rauch Figure A.19: Embodied Energy Comparison Source: Kapfinger,O, Simon, A (2011).
Internally, the wood used for floors originated from woods within this locality reducing transpor ng distances. In addi on, the use of earthen materials helped to improve the thermal comfort of the house in comparison to conven onal materials. This advantage is in the materials ability to regulate internal air temperatures and humidity voiding any large fluctuaons between day and night temperatures [Fig A.20]. Figure A.23: Interior of Rauch House Source: Boltshauser Architekten and Buhler.B (Photographer) (2013)
Figure A.20: Thermal mass; Rauch house thermal performance, summer week Source: Kapfinger,O, Simon, A (2011).
Figure A.24: Exterior Rammed Earth Source: Boltshauser Architekten and Buhler.B (Photographer) (2013)
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The significance was enhanced by adding 30mm earth plaster onto the interior walls of the dwelling without pain ng as this would have hindered the earth’s hygroscopic effect. Through this the regula on of humidity was reduced to a range of 40% to 60% [Fig A.25]. The combina on of different local materials and earth materials in the building envelope was also accounted for resul ng in U values of around 0.3 W/m2k for walls and 0.1 w/m2k for the roof as shown in Figure A.26.
Figure A.25: Hygric mass; Rauch house rela ve humidity, summer week. Source: Kapfinger,O, Simon,A ( 2011)
Figure A.26: Earthen materials applicability on housing envelope. Source: Adapted from Kapfinger,O, Simon, A (2011). This material and its precedent study is adapted from the report—Local Techniques submi ed in May’12 at the AA school. It was produced by the author and his peers. Source: Barros, J.L. et al . (2012). Local Techniques. AA School
141
FINDINGS AND CONCLUSIONS
Embodied energy of the house was significantly reduced by using natural materials.
The prevention from using plastic, silicones or synthetic additives was to avoid any indoor air pollution.
Materials were extracted locally reducing transporting costs and carbon emissions.
Rammed earth has the ability to regulate temperature within internal spaces limiting diurnal fluctuations in temperatures throughout the day and night.
Humidity levels are kept within a constant range of 40% to 60% within the internal spaces due to the rammed earth with less respect to the external environmental conditions in comparison to conventional con‐ struction materials whereby fluctuations are still present.
Resulting U values due to the thickness and combinations of earthen construction materials led to the good thermal performance of the building envelope.
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143
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APPENDIX B
CLIMATIC ANALYSIS LIGHTING LEVELS Formula— E’ = Ein/(10‐2 X D.F.) Source: Robinson, D. (2003). Climate as a Pre-design Tool where: E’ = Threshold external illuminance Ein = Indoor design illuminance D.F. = Average daylight factor aim or to achieve Therefore for Ein = 300lux and D,F.—2.5 E’ = 12Klux
Figure B.1: Frequency and cumula ve frequency of wind speeds Source: Climpro. Data from Meteonorm v6.1.
Hours of occurrence
Cumula ve Hours of occurrence
Figure B.2: Frequency of Global Horizontal Solar Irradiance Source: Climpro. Weather data from Meteonorm v6.1.
Figure B.3: Frequency of air temperature swings Source: Climpro. Weather data from Meteonorm v6.1.
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ANNUAL DAILY AVERAGE OF GLOBAL HORIZONTAL IRRADIANCE (GHI)
JANUARY
FEBRUARY
MARCH
APRIL
MAY
JUNE
Source: Solar Energy Centre, Na onal Renewable Energy Laboratory
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JULY
AUGUST
SEPTEMBER
OCTOBER
NOVEMBER
DECEMBER
Source: Solar Energy Centre, Na onal Renewable Energy Laboratory
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APPENDIX C
COMFORT BAND AND PASSIVE STRATEGIES COMFORT BAND CALCULATION [Figure C.1 & Table t3]
Tc = 17.6 + 0.38To (Reference—Nicol et al. 1996)
Result —
Max Tc = 29.5°C
Min. Tc = 22.0°C
Adap ve comfort range: ± 3.5 K
Result -
Max TCH = 33.0°C Min TCL = 18.5°C Table T3: Thermal neutrality and thermal upper and lower limit. (Adap ve range—±3.5K).
Ta Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Ta dmin Ta dmax
Tc
TCL
TCH
(°C)
(°C)
(°C)
(°C)
(°C)
(°C)
13.1 17 23 29.3 33 32.6 31.2 30.2 29.2 25.5 19.9 14.4
8.1 11.3 16.9 22.3 27.1 27.7 28.0 27.1 25.0 20.1 13.2 8.8
18.9 23.3 29.8 35.8 39.1 36.7 34.8 33.6 32.9 31.6 27.0 21.3
22.0 23.5 25.7 28.1 29.5 29.4 28.9 28.5 28.1 26.7 24.6 22.5
18.5 20.0 22.2 24.6 26.0 25.9 25.4 25.0 24.6 23.2 21.1 19.0
25.5 27.0 29.2 31.6 33.0 32.9 32.4 32.0 31.6 30.2 28.1 26.0
Ta—Mean outdoor air temperature Ta dmin—Average daily min. air temperature Ta dmax—Average daily max. air temperature Tc—Thermal comfort neutral temperature TCL—Thermal comfort lower limit TCH—Thermal comfort upper limit
50 45 40 35
Temperature °C
30 25 20 15 10 5 0
Jan
Feb Ta
Mar
Apr Ta min
May
Jun Ta max
Jul
Aug Tc
Sep
Oct TCL
Nov
Dec
TCH
Figure C.1: Preliminary calcula ons of comfort band (3..5K).
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150
APPENDIX D FIELDWORK ANSWERS TO THE INTERVIEW QUESTIONNAIRE CONDUCTED BY AUTHOR WITH AR. REVATHI KAMATH ON 7TH JULY’12.
Source: Author
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Source: Author
152
Source: Author
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ANSWERS TO THE INTERVIEW QUESTIONNAIRE CONDUCTED BY AUTHOR WITH MR. DHUNAS ALI ON 10TH JULY’12. DUE TO ISSUE WITH LANGUAGE AND FAILURE TO UNDERSTAND CERTAIN QUESTIONS BY OCCUPANT, SOME OF THEM REMAIN UNANSWERED.
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Source: Author
155
Source: Author
156
157
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APPENDIX E ANALYTICAL WORK TAS MODELS
Figure E.1: View of model in EDSL TAS (2% WFR) Source: EDSL TAS
Figure E.2: View of model in EDSL TAS (10% WFR) Source: EDSL TAS
Figure E.3: View of model in EDSL TAS (Addi onal Small Openings) Source: EDSL TAS
Figure E.4: View of model in EDSL TAS (Roof Top Opening) Source: EDSL TAS
Figure E.5: View of model in EDSL TAS (0.5m Underground and 1m high wall around except at window openings) Source: EDSL TAS
Figure E.6: Solar gain during summer and monsoon season with different window to floor ra o. Source: Radiance using Ecotect v2011.
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Table T4: Graph showing no. of hours the indoor temp. is above 33°C during summer and monsoon—Day and Night.
Source: A er EDSL TAS
Figure E.7: Graph showing no. of hours the indoor temp. is above 33°C during summer day for various interven ons. Source: EDSL TAS
Figure E.8: Graph showing no. of hours the indoor temp. is above 33°C during summer night for various interven ons. Source: EDSL TAS
Figure E.9: Graph showing no. of hours the indoor temp. is above 33°C during monsoon day for various interven ons. Source: EDSL TAS
Figure E.10: Graph showing no. of hours the indoor temp. is above 33°C during monsoon night for various interven ons. Source: EDSL TAS
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INTERVENTIONS TO BASE CASE IN ORDER A
—New CSEB Bhunga with Tiled Roof (Base Case)
B
—A + Adding glazing to openings with Night Time Ven la on Schedule (NTV)
C
—B + Opening doors during night to provide NTV
D
—C + Adding 50 mm Mineral Wool Insula on to the roof from inside.
E
—D + Increasing window to floor ra o to 10% from current 2%
F
—E + Crea ng small opening measuring 0.15m x 0.15m (15 in no.) on the envelope.
G
—F + Crea ng circular opening in the roof measuring 0.60m².
H
—G + Pain ng the roof and walls white
I
—H + Pu ng structure 0.5m underground and crea ng a berm all around except at openings. (earth sheltering)
J
—I + Tiles painted white (minus insula on)
Jb
—I + Thatch roof (minus white paint and no insula on)
Jc
—I + Thatch roof over les (no white paint and no insula on)
Effect on indoor temperatures in the summer and monsoon season can be seen on the next page.
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Source: EDSL TAS
Figure E.11: Graph showing effect on indoor temperatures with several interven ons (Cumula ve) in summer season
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Source: EDSL TAS
Figure E.12: Graph showing effect on indoor temperatures with several interven ons (Cumula ve) in monsoon season.
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MATERIAL SPECIFICATIONS Table T5: Details of CSEB blocks used in the TAS model.
Table T6: Details of cement rendering used in the Model.
Source: EDSL TAS
Source: EDSL TAS
Table T7: Details of door used in the TAS model.
Table T8: Details of glazing used in the TAS model.
Source: EDSL TAS
Source: EDSL TAS
Table T9: Details of mud walls used in TAS Model.
Table T10: Details of thatch roof used in the TAS Model.
Source: EDSL TAS
Source: EDSL TAS
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Table T11: Details of ceramic le used in the TAS Model
Table T12: Details of stone plinth used in the model
Source: EDSL TAS
Source: EDSL TAS
SCHEDULES Table T13: 24 hour schedule
Table T14: NTV schedule
Source: EDSL TAS
Source: EDSL TAS
Table T15: Fan schedule
Source: EDSL TAS
Table T16: Light schedule
Source: EDSL TAS
INTERNAL CONDITIONS Table T17: Details of internal condi ons used in the TAS model
Source: EDSL TAS
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SHADING STUDY Shading study was carried out using Autodesk Ecotect v2011 for two window sizes (0.30 x 0.30 m and 0.70 x 0.70 m) Current roof overhang is 0.45m which proves to be sufficient in blocking the high angle sun in the summer months and allowing the low angle sun in winters in both window sizes. These results allow modifica ons to be made to the window size (above the current sill height only).
6:00 AM
9:00 AM
3:00 PM
12:00 PM
6:00 PM
Figure E.13: Shading on south façade (2% WFR) produced by 0.45m roof extension on Summer Sols ce (21st June) Source: Autodesk Ecotect v2011
6:00 AM
9:00 AM
3:00 PM
12:00 PM
6:00 PM
Figure E.14: Shading on south façade (2% WFR) produced by 0.45m roof extension on Winter Sols ce (22nd December) Source: Autodesk Ecotect v2011
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6:00 AM
9:00 AM
3:00 PM
12:00 PM
6:00 PM
Figure E.15: Shading on south façade (10% WFR) produced by 0.45m roof extension on Summer Sols ce (21st June) Source: Autodesk Ecotect v2011
6:00 AM
9:00 AM
3:00 PM
12:00 PM
6:00 PM
Figure E.16: Shading on south façade (10% WFR) produced by 0.45m roof extension on Winter Sols ce (22nd December) Source: Autodesk Ecotect v2011
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