«CSAAR (7: 2010: Amman) Sustainable Architecture and Urban Development \ Edited by Steffen Lehmann, Husam Al Waer, Jamal AI-Qawasmi. Amman: The Center ...»
For recording indoor c1imatic variables, the bedroom was selected which is occupying the southwest corner of the house. This is the hottest corner of the house according to user experience. The selected room (figure 1) Sustainable Architecture and Urban Development receives solar radiation for a longer period compared to other two rooms and also from a study of Sharma (2002), he found that the relation between hot category rooms and cardinal locations, the west side room took the highest position and southwest room took the second highest position in Bangladesh. This research selects the worst corner of the selected house to justify the thermal performance of the traditional house in Bangladesh.
The room height is 2.8m. The size of the bedroom is 3.3m wide by 3.6m length (figure 3). This room has two windows of Im wide on west and east side periphery and two doors. This room is connected to living area through a door. Walls are made with 150mm by 150mm wooden post and corrugated sheets. The ceiling is made of 37.5mm thick wooden planks with 125mm by 75mm wooden beams. Furniture of the room consists of a wooden double bed, wooden wardrobe, wooden cabinet and a wooden study table with chair. The floor is raised from the ground and made by wooden planks. There are two 60 watt florescent Iights (one is regularly used and the other is occasionally used) and one ceiling fan in the test room. The outer surface of the upper space is made of corrugated iron sheets. It is directly exposed to the sun. Thc extended roof protects the windows of upper space from sun and rain. The upper space has four windows on west and east wall, which are 1.25m by Im wide. The window ofnorth and south side of the upper space is c1osed. The floor of the upper space is of wooden planks. In this area there is an incandescent light, which is used occasionally. Generally upper space is used as a store.
3.2 Experimental Procedure
The field measurement aim was to find out the uncomfortable hours in Bangladesh traditional house. To justify the use of The Renewable solar energy du ring uncomfortable period to enhance the indoor comfort environment. The selected test house has a buiIt-up area of 37.8sqm incIuding two bed rooms with small living area.
Thermal Data loggers were installed in the selected house (figure 2,3) for collection of air temperature and relative humidity data in the three zones, namely upper space, indoor living space and outdoor of the house. The remote data loggers recorded data with thc help of external sensors. Data were recorded at interval of every five minutes.
The controlling software assigns range of the logger interva1. The loggers are initiated by software Box Car Pro 4.0. The software is required for the downloading of data from the data loggers and in making the graph; and exporting data to excel file. Excel software also used for data analyses.
4 The use of solar energy at Bangladesh traditional house Energy is considered an enabling medium for economic development.
Renewable solar energy is a common practice of decreasing the quantity of energy used. Because of the lack of widespread coverage of centralized energy services and because of the financial and environmental costs of fossil and organic fuel, renewable energy should be considered for traditional housing at rural areas in Bangladesh. At the moment, harnessing solar energy using photovoltaic (PV) solar panels for electricity generation Is the most applicable option among other renewable energy technologies for utilization at the individual homestead level.
• Important positive outputs of electricity supply are increased scope for children's evening education and indoor income-generation.
• Current prices of solar energy systems are prohibitive for very poor households, but affordable for slightly better-off households. Organizations should promote and motivate households that can afford it to invest in solar energy systems.
• Organizations such as the Grameen Bank and BRAC are providing solar energy systems as part of micro credit programs. Other organizations should follow this example and build upon existing experience to develop flexible and soft financing schemes. Solar energy systems are advantageous in flood-prone areas because the panels are raised on a pole or on the rooftop and thus avoid damage by floodwater (ADPC, 2005).
Sustainable Architecture and Urban Deve!opment 253 5 Government Program of Renewable Energy in Bangladesh 62 KW solar PV is installed by Rural Electrification Board of Bangladesh 10 KW solar photovoltaic systems installed by Local Government and Engineering Department in 30 cyclone shelter.
5.1 Private Sector 5.1.1 Grameen Shakti:
A "not-for-profit" company involved in promotion of renewable energy resources for poverty alleviation Installed 4695 Solar Horne Systems up to July 2010. It was initiated in 1996 to 'rescue the rural people from energy poverty which hinders their socia! and economic devetopment'. Its main objective is 'to produce electricity to fulfil the minimum requirement of electrical power after dusk in the remote rural areas Bangladesh where conventional electricity could not reach in foreseeable future (social goal). 'It effectively captures synergy between renewable energy technology and rnicro-credit in order to give the rural people a chance to improve their quality of life and also take part in income generating activities. Solar Prograrn - for marketing solar horne systems through a network of branch offices with a soft loan prograrn.
Figure 6: Bangladesh traditional house and Solar panel over its roof.
to make the system more easily accessible by rural households GS seils PV systems on credit.
4. Now the credit system is as foJlows:
Customers pay 15% as down payment, and the remaining 85% is paid in monthly instalments within a 3 year period.
5.1.3 Grameen Shakti faced Initial Challenges Like
• Lack ofrural network
• No knowledge or awareness among the rural people
• Lack oftrained manpower
• High upfront cost of renewable energy technologies
• Lack of funding sources 5.1.4 The cost ofproduction and operating time
6 Result of Research Figure 7: Profile oftemperature of outdoor and traditional house indoor.
The research result is analyzed by the combination of the thermal performance of BTH and the use of solar energy. From the result of the field study (figure T) it can be conclude that the internal environment of BTH is comfortable despite the over crowded condition of the dense outdoor condition of Dhaka city even without any advanced mechanical means like Ae or cooler for controlling the indoor temperature. This is because of higher cross ventilation rate in indoor areas, wooden elevated noor, use of all light weight materials with low time lag and weil ventilated double layer roof section. (Upper space). Upper space protects the indoor living space from the direct solar radiation. In BTH, it noted that thermally the BTH representing indoor comfort condition at 5pm to 10am is always with in comfort temperature range (24 oe to 32°C). According to the research conducted by Mallick (1994), air temperature for comfort with no air movement and for people wearing normal summer clothing, engaged in normal household activity indoors are within the range of 24 oe and 32 oe and for relative humidity between 50% and 95%. In still air condition people feel comfortable even in higher humidity, wh ich is expected response in a location where humidity is generally high for most of the Sustainable Architecture and Urban Development 257 years. With the introduction of airflow, relative humidity up to 95% is tolerated.
The time (after 5pm) when maximum people back to horne 8TH already become comfortable. So the construction elements of 8TH can respond with outdoor climate. When the outdoor air temperature is extremely higher then the indoor air temperature of 8TH tends to be lower.
Figure 8: Plotting ofthe indoor air temperature and the indoor relative Humidity of B.T.H within summer comfort zone. (Source: Authors) From the comfort zone analysis (figure 8 ) it can be seen that the relationship between hourly air temperature and relative humidity with superimposing the summer comfort zone (24°C-32°C). Scatter diagram shows 71 % points are inside the comfort zone in the 8TH. Therefore indoor condition in the traditional house is more comfortable to live for occupants.
Figure 9: Profile o"nd~~'tcoJi1fort hours in both B.T.H within 24 hours.
(Source: Authors) Rumana Rashid Aecording to figure 9, the thermal performance capability was indieated by longer period of thermal eomfort duration in indoor of BTH is justified by considering the thermal eomfort hours. In BTH the comfortable ho ur within 24 hours i8 16 to 17 hours. Only for 7 to 8 ho urs i8 uneomfortable during day time and this period people do not stay at horne. The eombination of 10 watt three energy Iights and one fan is operating by use of renewable solar energy i8 enough to solve this problem. Lights are use only during night time, fan is using during uneomfortable period to enhance the eomfort environment. The Renewable solar energy is now a very eommon use in BTH. The solar lanterns emit omni direetional light is use for night at least 4 hours on a one hour solar charge within one day. Through this sustainable strategy without any use of eleetrieity in the BTH have an ability to provide sustainable life style in a better natural designed house. Renewable solar energy is efficient to solve energy problem in Bangladesh. The result of the minimum use of solar energy ean make the BTH more comfortable and sustainable.
BTH has shown a weil designed energy saving architeeture in the warm humid tropics whieh can save energy. by obtaining it from sun. The BTH emphasises house orientation, cross ventilation, effeetive upper spaee as insulation, adequate number and appropriate size of windows, which ean faeilitate low energy consumption. By utilizing natural resourees that are non-toxie and renewable. With less use of energy it's also reduees the level of C02 and air pollution. The BTH requires less upkeep and provides a healthy and comfortable environment for oecupiers. Solar energy strategy tools in BTH provide guidance to young designers. The use of solar energy in traditional house is a powerful hedge against future energy uncertainty in Bangladesh. Loeal climate responsive traditional house design and the implieation of renewable solar energy, makes BTH more energy effieient structure. It is a sustainable environmental and economical policy to reduee poverty of the under development country in world through the use of renewable solar energy in traditional house.
Acknowledgement In the name of Allah, the most Graeious, the most Mereiful, tor giving me the determination and will to complete this study. I would like to say thanks to University Teehnology Malaysia.
Sustainable Architecture and Urban Development 259 Reference ADPC, Hand Book on "Design and Construction of Housing on Flood Pom Rural Area of Bangladesh", 2005, Alexander, 1984, "energy design tor architects" page 5 Bijon Behari Sharma, HA study of the [actors for thermal eomfort in residential high-rise in Dhaka city". 2002 Brenda and Robert Vale, 1991,"Green architecture". page 182.
Dirk Rilling, et, al, "Lowering inside temperature of building by automatie optimum generation' Proeeedings 9th Sevar + 2nd Isssee 2008.
'Humanity + Technology" GOLDSEA, 'Asian Nations Begin Investing in Energy effienc,' Asian American Daily, Online, Harry Boswell and Stephanic Becon "Cooltek -a green and sustainable horne in malaysia." Proceedings 9th Sevar + 2nd Isssee 2008. 'Humanity + Technology'. http://goldsea.comlAsiagate/603/02energy.html Khandokar Shabbir Ahmed, "Approach to Bioclimatic Urban Design For The Tropics with special Reference to Dhaka, Bangladesh," Ph.D.,Thesis, Mallick, F.H, 'Thermal Comfort for Urban Housing in Bangladesh', Ph.D. thesis (unpublished), A.A. School of Arehitecture, 1994.
Olgay, V., Design with Climate, Princeton University Press, New Jersey, 1963.