http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/65 2026-04-22T13:28:58Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/661 FABRICATION OF A LOW TEMPERATURE DIFFERENTIAL STIRLING ENGINE ALAM, MD. KHURSHED; ISLAM, MD. ARAFAT; UDDIN, MD. AHSAN In recent years, understanding of the stirling engine has enjoyed considerable growth. Research and development on the stirling engine has steady progressed, and many new insights, inventions, and potential applications have many discovered and explored. One of the most exciting recent developments is the so called “low temperature differential” stirling engine. This new type of stirling is capable of running on very small differences in temperature between the hot and cold sides, or better to say, between the warm and cool sides. Low temperature differential stirling engine have been built that run on differentials ranging from just under 100°C (180°F) down to an incredible 1/2°C (1°F). This means that stirling engines can now utilize low grade heat sources for their operation ranging from passive solar or geothermal energy to industrial process waste heat. Weather low temperature differential stirling engines can be put to practical use is an open question and still the subject of ongoing research and development work is being carried out worldwide at universities, government laboratories, and in private sector. The objective of this project was to examine the history and development of Stirling Engines and through the process of examination, take the concepts and fundamental Characteristics of Stirling engines, and build a working model. The ultimate goal of this Project was to create a reproduction of James Senft’s N-92 Low Temperature Differential Stirling Engine and also built another N-92 model stirling engine with rescaling of its size and then analyze their performance, make some comparisons between two models and also fine out various difficulties of this fabrication technique. 2009-12-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/660 PERFORMANCE EVALUATION OF SOLAR FLAT PLATE COLLECTOR Alam, Capt. Alija; Uddin, Minhaz; Haque, Md. Nazmul The analysis of thermal performance of the flat-plate collector includes parameters such as solar intensity, ambient temperature and configuration of flat-plate collectors etc. In this paper, the effect of the parameter (Ti- Ta)/IT on thermal performance of glazed flat-plate solar collector was experimentally analyzed for water heating application in winter climatic condition. The flatplate collector consists of the total surface area 0.6656 m2 and the copper tubes are integrated beneath the absorber plate. The plate has a selective coating with high absorptivity of 92% and the heat transfer fluid flowing in the tubes is water. In the paper, evaluation of useful heat gain or collector efficiency has been done. It is based on steady state analysis and by calculating the thermal performance of liquid flat-plate collector. Results show that the flat-plate collector gives good performance and provide a desire quantity of hot water. 2017-12-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/659 ENHANCEMENT OF HEAT TRANSFER IN A PIPE FLOW USING A SWIRLING PERFORATED TWISTED TAPE INSERT Noon Oishe, Sadia; Rahman, Md. Mostafizur; Ahmad, Shahrokh; Bin Ehtesham, Md. Sakib With the advancement of science and technology heat transfer enhancement has become an important term in the field of engineering research since the effectiveness of heat exchangers are increasing through suitable heat transfer enhancement techniques. The purpose of research paper is to increase the heat transfer coefficient by operating the heat exchangers at smaller revolution per minute. This signifies an achievement of reduction of pressure drop corresponding to less operating cost. However different researches were done by using various enhancement techniques. This study has used two types of rotating perforated twisted tape insert to observe the various heat transfer coefficient, heat transfer rate and heat transfer enhancement efficiency. One tape was fully twisted and another tape was partially twisted. The shape of the twisted tape creates turbulence flow. The turbulence flow (swirl flow) generated by twisted tape promotes greater mixing and high heat transfer coefficients. An arrangement scheme has been developed for the experimental investigation. For remarking the rate of change of heat transfer, temperature has been measured numerically through the temperature sensors with various flow rates and RPM. The volume flow rate was varied from 10.3448276 LPM to 21.045574 LPM and the rotation of the perforated twisted tape was varied from 50 RPM to 400 RPM. Experiment demonstrates the effectiveness of the results of the proposed approaches. It is shown that the suggested method of heat transfer enhancements is much more effective than existing methods, since it results in an increase in heat transfer area and also an increase in the heat transfer coefficient and reduction of cost in the industrial sectors. 2017-12-01T00:00:00Z http://dspace.mist.ac.bd:8080/xmlui/handle/123456789/658 EXPERIMENTAL INVESTIGATION ON COUNTERFLOW INDUCED DRAFT COOLING TOWER AND PERFORMANCE ANALYSIS Akter Joty, Mahmuda; Sharar, Shadman; Hosaain Khan, Md. Solaiman Cooled water is necessary for air conditioners, manufacturing processes, power generation and many other purposes. Cooling tower is an equipment used to reduce the temperature of water by extracting heat from water and emitting it to the atmosphere. Cooling towers are able to lower the water temperatures more than other devices that use only air to reject heat, like the radiator in a car and are therefore more cost-effective and energy efficient. In the past most of the processes requiring cooling used piped town water through the equipment. After cooling the equipment the water was drained to the gutter. So, the water was totally wasted after using it once. Cooling towers were introduced so that the wastage of water can be reduced by recycling the water. Cooling towers make use of evaporation. Some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere. The evaporation process only takes place on the surface of a liquid and needs latent heat of vaporization to happen. Sensible heat is drawn from the body of the water to the surface to supply the energy needed for the latent heat. It can be seen that for a little evaporation a lot of sensible heat will be needed therefore the main body of the circulating water is cooled for very little loss of water. The main purpose of this study is to work on developing mathematical model for cooling tower and examine methodically the performance of a model of closed loop 10 RT counter flow induced draft bottle type cooling tower which has been developed only for this project purpose. A detailed mathematical model for a counter flow induced draft cooling tower has been developed using Merkel Theory. Dr. Merkel developed a cooling tower theory for the mass and sensible heat transfer between the air and water in counter flow cooling tower. Several experiments has been conducted by changing the L/G (L= water flow rate; G= air mass flow rate) ratio with the help of changing the flow rate (L) of water to observe the behavior of different characteristics, represented in graphical form. Tower characteristics graph has been plotted at 90%, 100% and 110% water flow rate. The performance prediction of cooling tower related with the performance curves by means of the simple method is made by a few design parameters as well as water flow rate, L/G, KaV/L (Tower Demand), range, cold water temperature, wet bulb temperature, and fan BHP. The performance prediction by the detail method is requiring all the actual cooling tower dimensions, thermal rating conditions, and all the mechanical rating conditions. Calculation of pump selection for the circuit has been shown. The efficiency obtained from the experiment we have conducted varies from 35% to 45% which indicates the good performance of the system we have developed. 2017-12-01T00:00:00Z