ASSESSMENT OF RAMMED EARTH AS EXTERNAL CLADDING FOR THERMAL COMFORT

Transcription

1 ASSESSMENT OF RAMMED EARTH AS EXTERNAL CLADDING FOR THERMAL COMFORT AND ENERGY CONSUMPTION OF A LOW COST HOUSE IN BANGLADESH PRESENTATION BY : JAHER WASIM Structural Engineer Mantissa Design and Consultant M.Sc. in Civil and Structural Engineering, BUET (ongoing) B.Sc. in Civil Engineering, BUET (2014) wasim@jaherwasim.com Phone: Website: 1

2 What is Rammed Earth? Rammed Earth is a technique for building walls using natural raw materials such as earth, chalk, lime or gravel etc. 2

3 Rammed Earth Constituents Earth + Gravel Silt Content Clay 45 to 80% ( by mass) 10 to 30% ( by mass) 5 to 20% ( by mass) Maximum Aggregate Size Not Exceed by 10mm to 50mm 3

4 Benefits Of Building In Rammed Earth The compressive strength of rammed earth can be up to 4.3 MPa (620 psi). Noise Reduction Strong and Durable Low Maintenance Fire Proof Versatile Pest Proof Healthy and Environmentally Friendly 4

5 RAMMED EARTH IS CAPABLE OF BRINGING DIFFERENT ARCHITECTURAL TEXTURE 5

6 OBJECTIVE OF THIS STUDY Whether building provides a satisfactory level of thermal comfort after using Rammed Earth external cladding Investigating building energy consumption before and after using Rammed Earth cladding 6

7 THE CASE STUDIED A single storied low cost bungalow house of an estimated area of 3000 square feet The building located at Purbachal area of Dhaka City 7

8 Perspective View 8

9 Plan of the Rammed Earth House Studied 9

10 Data Analysis DesignBuilder Building Energy Simulation Software Was Used For This Study. Three Different Thicknesses of Rammed Earth Was Used in the Simulation. Rammed Earth Thickness R Value of Rammed Earth Wall ( w/m2) 100mm (4 in) mm (6 in) mm (8 in)

11 Data Collection The estimation of equivalent R-values of rammed earth wall was based on data collected in the field measurements on a rammed earth wall of a high-rise commercial building in Gulshan; Dhaka named SPL Tower in February

12 Thermal Properties Rammed Earth Thickness (mm) U Value (W/m2.K) Solar Absorptivity

13 Dimensional & Operational Parameter Building Zones Description Area (ft2) Volume (ft3) Bungalow Single Storied External East Facing Wall Internal West Facing Wall Structural Framing Beam, Column, Truss - - Floors 5 RCC Slab - - People 4 nos - - Lighting Use of Daylight

14 Results and Discussions 14

15 Thermal Comfort Measuring by Room Temperature Comparison of Room Temperature for Different Rammed Earth Thickness 15

16 Thermal Comfort Measuring by Relative Humidity Comparison of Relative Humidity for Different Rammed Earth Thickness 16

17 Effects on Energy Consumption Comparison of Annual Energy Consumption for Different Soil Thickness 17

18 Effects on Envelope Thermal Transfer Value Comparison of ETTV to Different Rammed Earth Thickness 18

19 Conclusion This research has shown that the use of rammed earth in a single storied bungalow building at Bangladesh could result in a saving of 5 to 28% of total annual energy consumption. The study also shows that an optimum reduction of 4.5 to 13.5% on room temperature, 5.5 to 22% on relative humidity with different rammed earth thickness of mm as a measure of thermal comfort. The envelope thermal transfer value reduced by 5 to 20% due to the application of different thicknesses of exterior rammed earth wall. 19

20 References [1] Rammed Earth: Design and Construction Guideline; Book by Peter Walker, Rowland Keable, Joe Martin, Vasilios Maniatidis [2] Veronica Soebarto; Analysis of Indoor Performance of Houses Using Rammed Earth Walls, Proceedings of 11 th International IBPSA Conference 2009 [3] DesignBuilder; A product of DesignBuilder Software Ltd, UK [4] Guidelines on Envelope Thermal Transfer Value of Buildings; [5] Bangladesh Meteorological Department, [6] American Society of Heating, Refrigerating and Air-conditioning Engineers Inc. ASHRAE 55- Thermal Environmental Conditions for Human Occupancy, Atlanta, GA (2004) 20

21 Thank You 21