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Item Design, construction and performance analysis of a solar powered dual mode desalination system for water purification(University of Dhaka, 2016-11-20) Shishir, Asif JamanHuman life is based on water. Safe drinking water is one of our fundamental needs. Water is one of the most abundant resources on earth covering 75% of the planet’s surface. About 97% of the earth’s water is salt water in the oceans, and a tiny 3% is fresh water. Sea water contains large amount of salts. The salts exist in the form of chloride, sulfate, sodium, magnesium, potassium etc. Chloride and sulfate contribute to about 55% and 31% of sea salts respectively. Eating small quantities of saline water are not harmful, but more can be dangerous, ultimately producing fatal seizures, heart arrhythmias and kidney failure. Other than salts, there are many other unwanted elements, like bacteria, Parasites and heavy metals in the water. Major parts of Bangladesh do not have access to safe drinking water. Fresh water which was once obtained from rivers, lakes and ponds in plenty is now becoming scarce because of industrialization and population explosion. Increased irrigation of land for producing larger amount of food adds to the fresh water scarcity. Also, the available portable water is now increasingly being polluted by industrial and sewage waste. Therefore, there is need to purify the water to make suitable for drinking. It would be feasible to address the water-shortage problem with seawater desalination; however, the separation of salts from seawater requires large amounts of energy which, when produced from fossil fuels, can cause harm to the environment. Therefore, there is a need to employ environmentally friendly energy sources in order to desalinate seawater. As a part of my thesis, I have made a single basin single slope desalination device, where I used dual mode thermal energy for quick vaporization. One is the thermal energy trapped from solar radiation through a transparent top cover. Another one is the thermal energy of DC heaters powered by Photovoltaic module. Designed device is renewable energy (Solar) based and environmentally-friendly. This can be used for water heating, desalination and purification. This report covers introduction into desalination, comparative analysis of current desalination technologies. Some general concepts are given for the proper selection of desalination method. Description of designed desalination device is given in detail. After that, its construction, total cost, performance, efficiency and results are given here. Device maintenance, drawbacks and few related points etc. are also studied. From this research, I have concluded that, solar powered dual mode desalination may not be a viable option at the present price structure, further research for efficiency improvement of device could make solar assisted desalination one of the most economically advantageous device.Item Design, construction and performance study of a low cost solar dryer for food preservation in Bangladesh(University of Dhaka, 2016-11-20) Biswas, Pias KumarThe solar drying system utilizes solar energy to heat up air and to dry any food substance loaded, which is beneficial in reducing wastage of agricultural product and helps in preservation. The objective of the thesis is to design, develop and evaluate performance of an indirect solar dryer using thermal energy storage for the drying of vegetables and other foods. Later the future prospects in Bangladesh have been discussed in details. This design was employed by measuring various features such as cost, efficiency, durability and has compared with the performance testing through parameters such as temperature, air velocity, collector efficiency and weight loss. It was shown that the use of this type of solar dryer reduced the drying time significantly and essentially provide better product quality compared with conventional drying method. The effect of temperature to moisture contents against time and rate of drying are studied in this thesis.Item Study of the present scenario of solar irrigation in Bangladesh and design of a new irrigation model to make the solar Irrigation system more feasible(University of Dhaka, 2016-11-20) Al-Amin; Tanni, Tasmiah FatemaBangladesh has a primarily agrarian economy. Irrigation plays a very important role in our agriculture as well as on our economy. During dry season, irrigation of the whole country faces an acute crisis due to load shedding of 1248 MW. As Bangladesh has good solar resources, with high availability during the peak irrigation season. Therefore, solar pumping of water for irrigation presents an innovative and environment-friendly solution for its largely agro-based economy. Infrastructure Development Company Ltd (IDCOL) is providing financial support to solar irrigation. Already 450 irrigation pumps are installed by IDCOL in different divisions of Bangladesh. In this paper, 450 project’s data are analyzed and the findings are shown by different important graphs. Different division’s radiation, water head and required water are mainly focused in the analysis which will be very supportive for upcoming irrigation projects. To accomplish the analysis on solar irrigation a practical field visit has been made at Poradaho, Kushtia.Thisis a project of Bright Green Energy Foundation (BGEF) and financed by IDCOL. After visiting the project and talking with the farmer, a comparison between solar pump and diesel pump is found which is very significant. In addition, the idea of mini-grid along with irrigation is originated considering the huge load shedding of that area. People of that area remain without electricity for approximately 6-8 hours in a day. For this mini-grid purpose, a small survey was also conducted on 50 houses of that rural area about their electricity demand during the time of load shedding. The mini-grid will be power by the extra energy coming from the irrigation panel. This is done simply by changing the run time of the motor in an efficient way. The run time of the motor varies with different seasons. HOMER software is used to calculate the cost analysis of the proposed model for irrigation along with ac min-grid. In this model, two welfares derive at a time. The first one is that rural farmer can get water for irrigation with a lower installment which is shown in the paper. The second one is the demand of electricity of rural people during load shedding can also be fulfilled from the ac mini-grid. Therefore, the overall cost will be minimized and the new irrigation system will be more feasible for rural farmers as well as for the owner also.Item Opportunities in implementation of sustainable and renewable energy policy in Bangladesh(University of Dhaka, 2016-11-20) Rahat, Munshi H. M.Bangladesh is a developing country which is facing severe energy crisis. The energy consumption over the time will increase also. Aside from that Bangladesh is also one of the vulnerable country due to climate change of the world. In order to satiate the energy crisis Bangladesh need to find an environment friendly way for energy production. Bangladesh has good potential for harnessing renewable energy sources such as solar, biomass, wind, and mini-hydropower. According to Goldman Sachas it is one of the “next 11” country also (Goldman Sachas). Renewable energy is the balanced point for energy production which can produce energy without harming the environment. This Work is focused on to put light on renewable energy sources that can fix our energy crisis in a sustainable way and hence find new opportunities. It does so through a critical review of policy and institutional settings, as well as present status and lessons learnt from pilot demonstration of a number of RET projects undertaken by different organizations. The aim of this study is to help the policy makers in formulating renewable and sustainable energy policies and future plans for Bangladesh through this field oriented argument.Item Wet chemical etching of solarcell for edge isolation(University of Dhaka, 2016-11-20) Mojumder, Tanvir HassanSolar Energy as an alternative for conventional resources is getting popular day by day. As fossil energy sources diminishing gradually and some of them have adverse effects on world climate. One of the most popular methods, now a day for harnessing solar energy is solar panel. Solar cell depends upon the photovoltaic effect for their operation. The efficiency of solar cell depends upon how much energy input of solar energy is converted as output current. Solar cell efficiency also dependent upon some characteristic parameters such as short circuit current (Isc), open circuit voltage (Voc) and fill factor (FF). Parasitic components affect these parameters. These resistive parameters are series and shunt resistances. Shunt in solar panel is a loss mechanism occurs due to defects. Volume shunts are material induced shunts can occur due to impurities, metal particles contamination or aluminum particle contamination while making grid fingers, are impossible to eradicate without destroying the cell. On the other hand, mostly occurred edge shunts due to crack, holes or scratches can be removed in many available techniques. During the manufacturing of solar cell, a very important step called edge isolation process affects IV characteristics of solar cell, which is critical to the efficiency of itself. Deep and crack-free edge isolation to increase shunt resistance in the solar cell achieves higher efficiency and eliminates the source of fatigue cracks to extend lifespan of solar cells. There are many techniques available for removing shunts. In this paper, wet chemical etching method by HNA, is used for edge isolation process. From the experiments results it is found that HNA etching improves the IV characteristics of solar cells and hence it improves the power curves. Efficiency of un-etched solar cells was 3.17% and 3.90%. After etching the solar cell efficiency increase up to 5.53% and 5.31% respectively. From these progressive results, it can be said that wet chemical etching has flawless demands for further study.Item Feasibility study of waste to energy and power generation of Dhaka city(University of Dhaka, 2016-11-20) Sohel Rana, Md.Bangladesh is a developing country with high population density and rich in natural resource. People of Bangladesh are gradually shifting from agricultural to a more service oriented economy. This means for millions of Bangladeshi now have the ability to consume an enormous variety of goods and services that were previously either unavailable or unaffordable. From small electronic items, such as cell phones, to large consumer goods like refrigerators and cars, Bangladeshi consumption has been steadily increasing and shows no signs of snoozing anytime soon. The flip side of this consumption boom is that the amount of waste generated has and will continue to increase correspondingly. Dhaka is the capital city of the country; people from different part of the country migrate for livelihood. So the City’s population rises rapidly and current population is about 14.6 million and per capita waste generation is about 0.42 kg per day. Within 2030 it will be 0.73 kg per day. Collection rate of waste is 65% includes recycled 15% of total waste generated in Dhaka. Given its increasing population trend, rapid expansion of urban areas, and scarcity of land due to very dense population, Dhaka needs a solution to its burgeoning solid waste management problem that will be sustainable, cost effective, and minimizes public health, ecological, and climate change impacts. Waste-to-energy (WtE) is a strategy that is effective, environmentally sound, and economically beneficial. There are many technologies for converting waste into energy. For example direct combustion, gasification, pyrolysis, composting, plasma arc, refused derived fuel etc. For Dhaka city composting ( i.e. anaerobic digestion ) will be a convenient technology because waste generated in Dhaka city is commonly organic material (vegetables, food, paper etc.) which contribute 65% to the total waste and has high moisture content (50%-60%). The main constraint for waste to energy facility is high initial investment. However in this study the initial investment assumes $50 million base on the different WtE facility around the world and the land will lend from government at the dump site and payback period will be 7.1 years at the end of the project total revenue earned by the project Tk 247.87 crore.Item Study and review of biogas experience in Bangladesh and other countries(University of Dhaka, 2016-11-20) Chy, S. M. NomanWith large amount of population (density 1113.98/km2) Bangladesh demand a large amount of energy. But its economic condition is not enough strong to yield and endure with demand of energy for increasing population and raising economy. Alternative source of energy especially biogas technology has been initiated in Bangladesh for many years. Bangladesh is blessed with congruous geographical location (200 34/ N – 260 38/ N, 880 01/ – 920 41/ E) for renewable energy and perfect weather condition for Biomass energy. It is a low lying and tropical country and its temperature is very suitable for the fermentation of organic materials throughout the year. But in this country biogas technology is not popular as it was presumed. This study is conducted with the desire to investigate the reasons why biogas technology is not yet popular as like as solar home system (SHS) in both grid and off grid areas in Bangladesh. The expense of per unit PV electricity is ultimately higher than biogas scheme. Poor people can‘t bear the expenditure for such technology but it is often seen that they have a solar panel on their roof. Bangladesh is eager to invest huge amount of money in fossil fuel based electricity plant and buy electricity from neighbour countries also. This study does not trying to discover the lacking of other renewable energy sources rather an attempt to investigate the experience of biogas technology in Bangladesh. Gradually Bangladeshi people is adopting renewable energy, it is now required to accelerate this adoption to complement the requisite amount of energy for extended population and blooming economy .This review work focuses on the drawback of biogas technology on the basis of opinion and speculation of who use and who does not use biogas. In addition, people will get benefits from improved plant growth and crop yields through bio-slurry use. The financial benefits are likely greater when switching from liquid petroleum gas (LPG) to biogas as opposed to changing from collected wood to biogas. In this way it will be possible to make a hit to economy and environment.Item Hydrogen: as an alternative energy source and its potentiality for Bangladesh(University of Dhaka, 2016-11-20) Al Asad, Mohammad HafizThis thesis paper is not only delineate about the hydrogen as a sustainable versatile alternative future energy as well as its potentiality in Bangladesh to fulfill the energy demand in future and to mitigate the carbon emission. The Hydrogen, has the key prospective to become the ideal means among the range of renewable energy arena. Molecular of hydrogen has the highest energy content per unit weight among the known gaseous fuel (143 GJ ton-1) and it is the only carbon free fuel which ultimately oxidize to water as a combustion product. Therefore burning hydrogen not only has the potential to meet a wide variety of end use applications but does not contribute to greenhouse emission, acid rain or ozone depletion as well. The use of hydrogen will contribute to significant reduction of these energy-linked environmental impacts thus it could be fruitful for increasing the acceptance of hydrogen as fuel. In 2011, Bangladesh was consume 1.09 quadrillion Btu energy as the reference of International Energy Statistics, February-2015. The energy we uses, 93.75% are from the fossil fuel, and 1.73% from hydro energy and rest of are imported. In average 58.81 million metric ton CO2 are emitted from the fossil fuel that we are uses per year in our country. In this scenario using the Hydrogen as an alternative energy source can play a key role to reduce the usages of fossil fuel and obviously to mitigate the carbon emission. The production, storage, utilization, percussion, environmental impact etc. are discussed in the point of view of Hydrogen an alternative energy source as well as its potentiality and prospective view of Bangladesh are also illustrate in this paper. We could certainly beseechers Hydrogen is the best choice of alternative energy and has fruitful potentiality in Bangladesh as I have seen in my research.Item Performance analysis of graphite and multi wall carbon nanotube based counter electrodes in dye sensitized solar cells(University of Dhaka, 2016-11-20) Raihana, KanijIn this research work, a new type of cost-effective metal-free counter electrode for dye sensitized solar cell is introduced. This new type of solar cell is environment friendly in nature which has been investigated by the researchers. Recently DSSC is becoming very popular due its organic nature and its flexible application in various fields. It can be integrated in building integrated photovoltaic cell, act as a window glass, can be a portable charger for electronic gadgets. The overall structure of the cell is a sandwich-like formation that has photo sensitized anode in the first part and counter electrode at the end. Here 4 types of counter electrode is prepared by doctor blade technique where graphite and multi-wall carbon nanotube mixture follows 4 different ratios of 0:3, 3:0, 3:1 and 3:1 (with PEG) on a 2×1.6 cm 2 indium-doped tin oxide substrate. The counter electrode is expected to show enhanced electro catalytic characteristics toward reduction reaction as well as low charge-transfer resistance at the counter electrode-electrolyte interface. In combinationwith a natural dye (Indian Blackberry), dye-sensitized TiO photo anode and a liquid electrolyte, the fabricated counter electrode DSSCs show 0.041%, 0.006%, 0.0139% and 0.0832% energy conversion efficiencies under 1 sun illumination (100mW/cm 2 , 1.5AM). The data is comparable to the efficiency of the DSSC with platinum electrode that is 0.01% under the same experimental conditions. Hence the finding suggests that graphite and MWCNT (with PEG) ratio of 3:1 is a promising alternative counter electrode for low cost dye sensitized solar cells.Item Fabrication and optimization of dye sensitized solar cell using carissa carandas dye(University of Dhaka, 2016-11-20) Huda, Syeda AshifaThis study presents an approach on the development of DSSC and the photo- electrochemical effect with natural Carissa Carandas dye sensitized Titanium Dioxide anode. To find the optimal performance of the dye Carissa Carandas was soaked in different solvent for varying time and the optimum time to soak anode in dye is measured by soaking anode in the dye for varying time. The optimum condition was soaking Carissa Carandas in ethanol solvent for 48 hours and soaking Titanium Dioxide anode in dye for one hour. The light conversion efficiency of the Dye-sensitized solar cell reached 0.10271% with short circuit density .8566 mA/cm² ,open circuit voltage 478mV and a fill factor of .2546.The UV-visible absorption characteristics of natural dye solution were shown to absorb in visible region at λ max= 535nm.