Emin Yilmaz

Design Experience Using Software Tools in Undergraduate Engineering Mechanics Courses

Statics, Dynamics, and Mechanics of Materials form the basic sequence of engineering mechanics courses in engineering curricula. Traditionally, these courses have been designated as “engineering science” courses with significantly more emphasis in analysis to reinforce engineering fundamentals, and little to no importance to “engineering design”. With the outcome based approach to undergraduate engineering education adopted by Accreditation Board of Engineering and Technology and the framework laid out by Engineering Criteria (EC 2000) significant reform efforts are underway to incorporate design experience throughout the engineering curricula. Most engineering programs across the nation have developed and implemented a freshman design course to introduce engineering design at the beginning of the college experience for engineering majors. To sustain the momentum, it therefore follows that subsequent courses should sustain the design emphasis in the freshman and sophomore years. Design, however, is a time consuming complex iterative process somewhat different from the convergent nature of engineering science. Modern software tools provide a time efficient and pedagogically effective way of integrating engineering design project with the engineering mechanics sequence without compromising the engineering science fundamentals. In this paper design projects that have been integrated in Statics, Dynamics, and Mechanics of Material courses offered by the author using software tools such as Working Model, MD-Solids, Pro-Engineer, Solid-works etc. supplemented by computational tools such as MATLAB and EXCEL are outlined. Discussion based on student feedback and relevance to ABET outcomes is also forwarded.Copyright

Air Conditioning Waste Heat to Domestic Hot Water: A Student Design Project

The goal of the “Domestic Hot Water Heater Using Air Conditioner (A/C) Waste Heat” design project was to introduce students to designing mechanical systems in the “ETME475-Mechanical Systems Design” course. The design project was assigned to two Mechanical Engineering Technology students as their second design project in the course. Students were asked to do their own literature search and create their own designs. Both of them decided to use a concentric-tube heat exchanger to extract heat from hot refrigerant gas to heat water residing in domestic hot water heater tank. Their literature search led them to some manufacturers. Since delivery time for concentric-tube heat exchanger was too long, we purchased a side-by-side-tube heat exchanger and got it installed on our Heat Pump. Some test runs were conducted to measure the efficiency of the unit and its effect on the Coefficient of Performance (COP) of the Heat Pump when heat pump is operated in A/C mode. Contrary to our expectations, results indicate that, COP values have been reduced by about 22%. Measured efficiency of the unit was about 18%. Students have designed a concentric-tube heat exchanger, turned in their final reports and orally presented their designs to the class.Copyright

LabVIEW and Measure Foundry Based Data Acquisition System for Mechanical Engineering Technology Laboratories

Since the ASYST data acquisition and analysis software was discontinued and the old versions of ASYST do not support new computer operating systems and new data acquisition boards, old computer data acquisition (CDAQ) system is being replaced with a new data acquisition system. The new microcomputer based data acquisition system consists of an i-3 microcomputer with 3.0 GHz CPU and Windows-7 operating system, a Data Translation (DT) DT-304, 12-bit, 400 MHz data acquisition board with STP-300 screw terminal, Data Translation Measure Foundry (DT-MF) software and DT-LV link software [2], a National Instruments (NI) PCI-6250, M-series, low level, 16-bit, 1.25 MS/s board with 4-module SCC-68 I/O Connector Block, four thermocouple-input plug-in modules and NI LabVIEW (NI-LV) software [4]. Data Translation’s DT-LV software links DT boards with NI-LV software. Most ASYST-based data acquisition and analysis application programs used in Mechanical Engineering Technology (MET) courses have been converted to NI-LV and DT-MF application programs.Purpose of this paper is to describe how our old data acquisition application programs were converted to new data acquisition application programs so that they may be used with our new data acquisition system. Descriptions of the experiments, equipment used, and experiences gained with laboratory experiments are given elsewhere [8–13]. Specifically: Reference [8] covers upgrades made to the Materials Testing Laboratory, including Tinius-Olsen [14] tensile testing machine; reference [9] covers design and development of data acquisition programs for the materials testing, including Tensile Testing of Materials experiment; references [11] and [12] cover Heating Ventilating and Air Conditioning (HVAC) experiments and use of DAQ system in these experiments; reference [13] cover all uses of DAQ system in MET at University of Maryland Eastern Shore (UMES).Copyright

Conversion of a Dune Buggy to a Hybrid Vehicle as a Systems Design Course Project

Department of Technology has purchased a used Dune Buggy years ago. It had a 6.8 horsepower Honda G65 engine with a centrifugal clutch to move the vehicle. Students in EDTE 341-Transportation Technologies course have tried, twice, to fix the engine, but they were not successful. As a student design project in ETME 475-Mechanical Systems Design course, during spring semester of 2009, three Mechanical Engineering Technology (MET) students, with the help of one Electrical/Electronics Engineering Technology (EET) student, have converted the vehicle to a hybrid vehicle. The purpose of the design project was to convert an internal combustion engine (ICE) driven Dune Buggy to a hybrid vehicle. ICE and Electric motor (EM) sizes were kept at about 6HP and cost was limited to no more than

Instrumentation for Performance Measurements of Heat Pumps With Commercial Desuperheaters

3000. ETME 475 is a three credit-hour course with two credit hours for lecture and one credit hour (two lab contact hours) for laboratory. Laboratory time is used to discuss the project(s) and cover basic knowledge needed for the specific project(s). Along with regular textbook homework sets, students are assigned to turn in project related assignments. Most weeks, both homework and project assignments were due. First half of the semester was spent on designing the hybrid vehicle. Second half of the semester was spent constructing it. There were three students enrolled in the course. One EET student worked on the project to do electrical/instrumentations systems design and wiring. At the end of the semester, Dune Buggy was able to move with the EM. However ICE stalled as soon as the magnetic clutch was engaged. The following semester, fall semester of 2009, another MET student worked on the project to modify wiring and replace the magnetic clutch with a centrifugal clutch. This work was done under two credit-hour, ETME 499-Independent Research in Mechanical Engineering course. At the end of the semester, the Dune Buggy was fully operational with EM and ICE, one at a time, or both at the same time. Two additional MET students worked on the vehicle during the spring semester of 2011 as one of their low-tech projects to improve safety by covering cover exposed areas of the dune buggy and paint it. This paper discusses the details and coordination of the project as a design project for senior level Mechanical Systems Design course.Copyright

Performance of Air Conditioners With Commercial Desuperheaters: A Green Energy Project as an Undergraduate Research

The current project is an extension of the original “ETME 475-Mechanical Systems Design” course project with a new National Instruments data acquisition board, a newly developed LabVIEW data acquisition program, and with a more realistic heat transfer loop. The study covers performance of our heat pump operating in A/C mode as well as in heating mode with a commercial desuperheater (a cross-flow heat exchanger). For this project, the experimental set up consisted of a desuperheater spliced into Trane XL1000, 2-ton, 10-SEER heat pump and a heat transfer loop with a 72-liter hot water storage tank. The instrumentation consisted of seven copper-constantan thermocouples and a LabVIEW-based computer data acquisition system. The thermocouples were used to measure refrigerant, water, indoor air and ambient air temperatures. The LabVIEW based computer data acquisition system was used to record temperatures. Indoor airflow rate was previously measured using Alnor LoFlo balometer. Results indicate that, depending on the water temperature in the desuperheater, heat pump Coefficient of Performance (COP) dropped 6–18% in A/C mode and 8–38% in heating mode. Again depending on the average water temperature in the desuperheater, the desuperheater efficiencies ranged from 12% to 27% for cooling and 11% to 39% for heating. Although even modifying an existing LabVIEW program was a challenge, the student who worked on it and the author has gained very valuable experience and enjoyed the work.Copyright

Design, Construction and Use of an ASTM Guarded-Hot-Plate Apparatus as an Independent Research Project

The goal of the design project titled “Domestic Hot Water Heater Using Air Conditioner Waste Heat” was to introduce students to designing mechanical systems in the “ETME475-Mechanical Systems Design” course. Two students completed the design project in spring 2007. Some test runs were conducted with a commercial desuperheater to measure the efficiency of the unit and its effect on the Coefficient of Performance (COP) of the Heat Pump when the heat pump is operated in air conditioning (A/C) mode. Contrary to author’s expectations, results indicated that, COP values were reduced by about 22%. Measured efficiency of the desuperheater was about 18% [1]. The current project is an extension of the original project with the new National Instruments data acquisition board, a newly developed LabVIEW data acquisition program, and with a more realistic heat transfer loop. The study covers performance of the heat pump operating in A/C mode as well as in heating mode. Results indicate, depending on the water temperature in the desuperheater, heat pump COP dropped 6–17% in A/C mode and 8–38% in heating mode. Again depending on the average water temperature in the ECU, the ECU efficiencies ranged from 12% to 27% for cooling and 11% to 39% for heating.Copyright

Winning the ASEE 2006 Robotics Design Competition: Guiding Students to Success

Thermal conductivity and/or R-value of materials may be measured using methods specified by American Society for Testing Materials (ASTM) or International Standards Organization (ISO). In general three methods are commonly used: the Hot Box, the Heat Flow Meter, and the Guarded Hot Plate. The project was assigned to a Mechanical Engineering Technology student as a research project to satisfy requirements for, senior level, “ETME-499-Independent Research in Mechanical Engineering Technology” course. Student was asked to do his own literature search for the available standard methods and select the most suitable standard method to design and construct an apparatus to measure thermal conductivity and/or R-value of insulating plane specimens. Student has decided to use the Guarded Hot Plate method since it did not require calibration and is simpler to construct. Before the standard was received, student has created some designs similar to the one described by the standard. Limited test runs indicate that polystyrene R-values were underestimated by 12–16%, and duct board R-vales were underestimated up to 22% at higher than 75 °F average specimen temperatures. Student has enjoyed designing, constructing and using the apparatus, which has real world applications. This project has forced him to use his machine design, strength of materials, thermodynamics, instrumentation, heat transfer and manufacturing processes knowledge. Paper will convey our design, construction and use experiences as well as the experience the primary author had in guiding the student towards a common goal in an “Independent Research” course.© 2008 ASME

Development of a More Efficient Defrost Control System for Heat Pumps

Robotics Model Design Competition sponsored by the Two Year College Division (TYCD) of American Society for Engineering Education (ASEE) provides an avenue for freshman and sophomore student teams in two year as well as four year colleges and universities to participate in a creative engineering design project. Historically Black Colleges and University - Undergraduate Program (HBCU-UP) at National Science Foundation (NSF) have provided support for development of ACTION (Advanced Curriculum and Technology-based Instructional Opportunities Network) at UMES. The ACTION program promotes inquiry based active learning and research projects among undergraduate STEM (Science, Technology, Engineering and Mathematics) majors. Engineering, Technology, and Mathematics students responded enthusiastically when the authors proposed the idea of participating in the (ASEE) 2006 Robotic Model Design Competition at one of the American Society for Mechanical Engineers (ASME) student section meetings at UMES in the fall of 2005. (The authors serve as the advisors for ASME student section chapter at UMES). The student leader of the section quickly put together a team of five freshman and sophomore engineering, engineering technology and mathematics students to develop a proposal to UMES ACTION program. The authors supported the proposal development efforts. The proposal got funded and provided the resources for project execution and travel. A team of eleven freshmen and sophomore students from Engineering, Engineering Technology and Mathematics departments of University of Maryland Eastern Shore (UMES) participated in the American Society for Engineering Education’s (ASEE) 2006 Robotics Model Design Competition project. The event was sponsored by the Two-year College Division (TYCD) of ASEE and was open to freshman and sophomore student teams from two year as well as four year colleges and universities. The competition required teams to design and build an autonomous robot capable of delivering ping pong balls to each of four corner pockets located on an 8ft×8ft plywood track in a sequence. Each team was evaluated on the basis of a written report, an oral presentation, and scores obtained from the best two runs out of four runs on the racing track. Sixteen student teams across the nation participated in the event. UMES entered two teams in the competition who called themselves “Hawks 1” and “Hawks 4”. The student team “Hawks 1” won the competition. Video clips of both design projects as they executed the specified task at the 2006 ASEE Robotics Model Design Competition can be viewed at: http://www.umes.edu/asme/robots.htm . This paper describes the design projects “Hawks 1” and “Hawks 4” and its relevance to ABET learning outcomes.© 2007 ASME

Development of a More Efficient Defrost Control System for Residential Heat Pumps

The purpose of this research project was to design a more efficient defrost control system for residential heat pumps. Defrost systems are used to melt the accumulated ice on evaporator coils of outdoor units. The purpose of the new control system is to prevent the initiation of defrost cycle when there is no substantial ice accumulation on the outdoor unit. Two of the envisioned ice accumulation sensing methods were (a). Increase in pressure loss across the evaporator coil and (b). Resistance change across two electrodes when ice bridges the electrodes. A differential pressure sensor was used to sense an increase in pressure loss across outdoor coil for this research project. Results indicate that, although maximum time interval of 90 minutes was used, about 55% of defrost cycles initiated were not necessary since there was no ice to melt. An ASYST based data acquisition system was used to monitor, measure and store key parameters. It is expected that with the new control system one can improve efficiency by about 3%. A similar project has been undertaken on a heat pump recently installed on our HVAC experimental unit as an undergraduate research project. Installation of temperature and humidity controlled enclosure, and thermocouples have been completed. Some results were reported here. If any additional progress is made, results of this project will be reported at the meeting.Copyright