ENVIRONMENTAL SIMULATION
SAIMUM KABIR
Environmental performance analysis for
DESCO Head Office [Design competition] Nikunja 2, Dhaka Prepared by Saimum Kabir (Architect and Assistant professor) for VERNACULAR CONSULTANT LIMITED
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ENVIRONMENTAL PERFORMANCE ANALYSIS The Environmental Performance of the proposed designed DESCO Head Office building is assessed in terms of four environmental variables; 1. Air Flow and Natural Ventilation, 2. Incident Solar Radiation 3. Daylighting, and 4. Thermal Insulation. To perform the analysis, internationally validated computer simulation tool ECOTECTÂŽ 2001 by Autodesk is used. The weather data for Dhaka is accumulated form the open source weather data bank of ENERGY PLUSÂŽ which is further verified and adjusted with local weather data as recoded by the Meteorological Department of Bangladesh.
Air Flow and Natural Ventilation As the project is located within a urban context surrounded by multistoried public buildings at south & north and residential buildings at west, new building block will have a potential impact on the micro environment especially in local air flow and ventilation pattern. The impact on the micro level airflow pattern, therefore assessed through a comparative analysis of two anticipated situations; Situation 1: A typical building block with mandatory setback; Situation 2: The proposed inclined building block with an exposure to south.
Figure1: Air circulation improves considerably when the building block is inclined towards north
The result shows that, the presence of REB building on the south creates a substantial wind blockage. A typical building block with minimum setback (Situation 1) restricts the air circulation around and through the building, where as a significant improvement is observed in case of situation 2 (proposed) (Fig 1). The slight outward inclination towards the prevalent wind direction creates an aperture for air to circulate far deep into the building. Moreover the operable curtain windows at north and south allow the air to flow across/through the building and thus provide naturally ventilated spaces (fig 2)
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Figure2: Flow vector analysis shows all the general office area will be naturally ventilated
Solar Radiation It indicates that the amount of solar radiation received by the building fabric in respect to its exposure to the direct sun. Here, solar radiation is calculated in terms of incident surface insulation assigned on four vertical building faรงade for the period of summer (from April- July). The overshadowing phenomenon by surrounding building block is also taken into account during calculation. Analysis shows that, maximum solar radiation received by the east west building fabric is about 15001800 Wh/m2. Use of concrete as wall material both in east and west faรงade will have positive result by absorbing the incident radiation on these sides. The avg radiation received by the south faรงade is at moderate level (ranging from 600-1800 Wh/m2) as it remains overshadowed by the REB building block. To minimize the heat gain from direct radiation, double glazed window panel at south faรงade is used. The north is the least exposed side and will remain shaded by the building mass itself. Full height single glazed curtain wall at the north will allow ample natural light with least amount of radiation. Even the plaza, pavement and driveway at the north will remain shadowed almost all around the year.
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Figure 3: The context model to analyze incident solar radiation in Ecotect® interface
North façade
South facade
West facade
East facade
Figure 4: The context model to analyze incident solar radiation in Ecotect interface
Daylight Performance The proposed building has a deep plan (104’ width and 11.5’ height/per floor) with opening at north and south sides and atrium at the centre. In fact, the central atrium has positive amplitude on the lighting level inside the building. The simulation result shows that, in proposed design the natural light level ranges from 300-3000 lux. These light levels suggest that there will no need of artificial lighting for the daytime except for the cloudy days, as the average lighting level required for an office work is as follows: Working area General office area Conference rooms and executive offices Reception area Corridors and lobby
Lighting level (lux) 300 300 150 70
Reference: Bangladesh National Building Code, November 15, 2006; Page 11217
The analysis is as follows:
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lu x 3 00 0+ 27 30 24 60 21 90 19 20 16 50 13 80 11 10 84 0 57 0 30 0
Figure 5a: Daylight distribution at 11th floor
Figure 5b: Daylight distribution at 3rd floor
Energy Load Energy load is calculated in terms of monthly heating and cooling loads. Considering comfort temp of 26 deg C, calculation shows that no heating is required all around the year. Very nominal cooling is required during the month of December, January (0 unit) and February. For the rest 9 months of the year cooling is required to achieve comfortable indoor environment. The monthly cooling requirement is given below (fig 6):
Heating load
Cooling load
Figure 6: Monthly cooling load requirements pattern for the proposed design
Passive breakdown of the heat gain source reveal that building fabric is responsible only 17% of total heat gain. Maximum heat will gain from direct solar radiation. GAINS BREAKDOWN - All Visible Thermal Zones FROM: January 1 to December 31
Category FABRIC SOL-AIR SOLAR VENTILATION INTERNAL INTER-ZONAL
Losses 35.9% 0.0% 0.0% 0.0% 0.0% 64.0%
Gains 17.2% 10.9% 66.2% 0.1% 0.6% 4.9%
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Figure7: Passive breakdown analysis shows that building fabric (red area) is responsible only 17% of total heat gain
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Daylighting analysis for Reedisha Food Factory
Daylighting analysis for
Reedisha Food Factory Valuka, Mymensingh
Prepared by Saimum Kabir (Architect and Assistant professor) for CUBEINSIDE DESIGN LIMITED
Daylighting analysis for Reedisha Food Factory
Summary: Daylighting level for Reedisha Food Factory is simulated using Autodesk Ecotect® 2001 (version 5) for the context of Gazipur, Dhaka. The 3d base model is prepared as per autocad reference drawing provided by the architectural consultant Cubeinside Design Limited and the following parameters are assigned to model:
Design sky illumination1 10500 lux CIE overcast sky condition Window cleanliness avg. X .90
Natural light values are calculated over the analysis grid for every floor level separately. The simulated result is showing in the following image
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Design Sky values are derived from a statistical analysis of outdoor illuminance levels. They represent the horizontal illuminance that is exceeded 85% of the time between 9am and 5pm throughout the working year. Thus they offer a WORST-CASE scenario that you can design to and be sure you meet desired light levels at least 85% of the time. The Design Sky you enter here is simply multiplied by the Daylight Factor at each calculation point to determine the actual daylight level.
Daylighting analysis for Reedisha Food Factory
The computed result shows, during day hours, there will be sufficient natural light (400-200 lux) (see Table 1.1) in the production area of first, 2nd and 3rd floor. The daylighting level at ground floor may not be sufficient enough and may require supplementary electric lighting even during daytime. Table 1.1: STANDARD ILLUMINATION REQUIREMENTS Activity Type Rough Task with large detail
Required Light level 200 lux
Ordinary task , medium detail
400 lux
Casual seeing
100 lux
It is tested, the High window contributes significantly to the light level, so clear glazing specially for High window (with or without louver) is strongly recommended. To enhance the contribution of reflected component in the overall lighting environment, the ceiling should be painted white. See the annex for floor wise simulation result.
Daylighting analysis for Reedisha Food Factory
Annex 01 : DAYLIGHING ANALYSIS FOR GROUND FLOOR OF REEDISHA FOOD FACTORY
Standard Range
Dark Area
Annex 02 : DAYLIGHING ANALYSIS FOR FIRST FLOOR OF REEDISHA FOOD FACTORY
Daylighting analysis for Reedisha Food Factory
Standard Range
Annex 03 : DAYLIGHING ANALYSIS FOR SECOND FLOOR OF REEDISHA FOOD FACTORY
Daylighting analysis for Reedisha Food Factory
Standard Range
Annex 04: DAYLIGHING ANALYSIS FOR THIRD FLOOR OF REEDISHA FOOD FACTORY
Daylighting analysis for Reedisha Food Factory
Standard Range
© SAIMUM KABIR saimum_arch@yahoo.com