Technology Hospital Collaboration In Thermodynamics

In order to provide a real example of applied thermodynamics, the Purdue School of Technology located in Columbus, Indiana and the Columbus Regional Hospital have agreed to work together to demonstrate and investigate the various thermodynamic systems operating at the hospital. During a junior-level Applied Thermodynamics class in the spring of 2003, the students were given a tour of the hospital facilities; although no specific projects were attempted using the hospital’s systems. This paper will outline specific projects at the hospital that may be assigned to students to supplement the classroom material. These projects will be presented to the junior-level Applied Thermodynamics class in the fall of 2004. Quantities such as power, heat flow, energy and efficiency will be explored along with the various thermodynamic cycles utilized throughout the hospital. Pressure, temperature, and volume data will be recorded and compared, especially between heat exchanger components. Examples of systems to be investigated include the water chiller with its cooling tower and associated air handling capabilities; the boilers, which produce high, medium and low pressure steam for various uses throughout the hospital; the oxygen-delivery system that starts with liquid oxygen and is converted to oxygen gas for patients. While this look at a real business and its utilization of thermodynamic principles will certainly benefit the students, the hospital facilities’ staff can expect highly detailed reports of their systems including analysis and potentially some recommendations for improvements. These reports may be used by the staff for training and learning activities that might help them understand why the corrective actions specified in their troubleshooting manuals are successful. P ge 9.220.1 Proceedings of the 2004 American Society for Engineering Education Annual Conference & Exposition Copyright © 2004, American Society for Engineering Education Introduction During the past several years, the Purdue University School of Technology at Columbus/Southeast Indiana has joined with Columbus Regional Hospital to offer two or three Technology in Action days for local high school students. The focus of this effort has been to introduce young people to careers at the hospital or in the medical profession that are unrelated to training in medicine. Indeed, careers in computer technology and mechanical engineering technology are emphasized. A short presentation is given by representatives from both the hospital and Purdue University informing the students of what they will see during the hospital tours that comprise the majority of the students’ visit. There are four separate tours: 1. the computer networking facilities 2. the computer technology section that provides hardware update/repair, software update/installation and other associated services to the hospital staff 3. the mechanical repair section whose purpose is to make repairs to hospital equipment such as beds, IV machines and other mechanical devices. 4. the hospital facilities management section The high school students are divided into four groups and each group tours each of the four areas. Typically, the tour of the facilities management section is led by co-author David Lenart. During the tour, the students have an opportunity to see areas of the hospital that much of the general public never sees, including the boilers that produce heat and steam, and the associated piping. Other highlights of the facilities tour include the system used to deliver gaseous oxygen to individual patient rooms; systems to heat and cool the hospital; power generating systems to provide back-up power in the event that power from the local utility is lost. Co-author Dr. Fuehne joined the students on these tours during 2003 and recognized the potential for active learning for thermodynamic and fluid power students by engaging them to investigate these systems with group projects. In order to judge how students might receive these projects, an Applied Thermodynamics class in the spring of 2003 was taken on a tour of the hospital facilities, emphasizing the thermodynamic systems. This tour did not involve specific group projects but gave the students an opportunity to observe the various thermodynamic systems of the hospital. Students generally found the tour of the systems interesting and enjoyed the opportunity to see real applications of the fundamental concepts they were studying. P ge 9.220.2 Proceedings of the 2004 American Society for Engineering Education Annual Conference & Exposition Copyright © 2004, American Society for Engineering Education Specific Potential Projects 1. Liquid/Gas Oxygen Handling System 1 A critical hospital system is the delivery of gaseous oxygen to patient rooms. The Columbus Regional Hospital (CRH) uses a system with one tank continuously supplying the piping system while a secondary tank containing at least an average day’s supply is held in reserve. Specifically, the system is a 3000/11000-gallon primary system with a 350/1500-gallon reserve. Brazed copper pipes are used for the piping network delivering the oxygen because of their increased resistance to ignition and lower combustibility than other materials. Similar oxygen compatible materials are used for other parts of the system. The oxygen starts as a liquid in an outside tank at a pressure of 150 psi. By undergoing a volumetric expansion to 90 psi, the liquid oxygen is evaporated and controlled by a pressure regulator set at 52 psi. Pressure limit switches are utilized at each zone to warn of low pressures. In patient rooms, centrifugal pumps create a vacuum of 20 mm of mercury. By using the equation below and noting the appropriate unit conversions, T this vacuum represents about 0.39 psi. Flow meters are used to control the flow of oxygen to the patient. The system is designed to handle about 20 patients simultaneously. The study of the evaporation process of the oxygen is an outstanding project related to tracking the oxygen as it moves through the vapor dome with changing pressure, volume and temperature. Figures 1 and 2 show the pressurevolume vapor dome and the pressure-enthalpy vapor dome for oxygen. On both plots the left side each curve up to the peak is the liquid line and the right side is the gas line. The boiling point of liquid oxygen under atmospheric pressure is -297.4 °F. When subjected to 150 psia pressure, the boiling point increases to -243.3 °F since additional heat is needed to overcome the pressure. In both of the figures, constant temperature lines run across the vapor dome. During evaporation, the pressure and temperature of a liquid-gas mixture remain constant as all the heat input to the system is used to change the phase of the oxygen from liquid to gas. As an example, in Figure 2 the difference between the enthalpies between state A and state B represents the heat required to convert all of the liquid oxygen to gas at 125 psia pressure and -235 °F. Under the vapor dome, the pressure and temperature are not independent, meaning that a change in pressure will produce Pressure {density of fluid} {gravitational constant} {height of fluid} = × ×