Part 1: Write a 2-3 page essay broadly discussing the choice of refrigerants for refrigeration systems. What are important considerations when deciding on a refrigerant for any type of refrigeration system (not just automotive applications)? Topics which may be discussed include desirable physical and thermodynamic properties, toxicity, cost, corrosion properties, etc. Use at least three references (none of these can be from the internet – they should be books, journal papers, magazine articles, patents, or other similar references) for your essay and be sure to properly cite all the works you refer to. You can use any standard reference format you like (e.g., APA, MLA, Turabian, etc.). Be consistent and use the same format style for all references. Compare at least 3 different potential refrigerants on at least 8 different criteria. You should weight the relative importance of each characteristic and quantify each as best as you can. For example, cost may not be as important since relatively little refrigerant would be needed in a car A/C system. In some cases you may use qualitative comparisons such as poor, good, better, best, etc. The best way to make the comparison of 3 refrigerants on at least 8 criteria is with a table, so they can be compared side-by-side. Finally, make a recommendation on what refrigerant you would chose for an automobile if you were going to manufacture an air-conditioning system for automotive use. Example Outline: 1. Introduction 1.1. Purpose of refrigeration 1.2. Sample applications 1.3. Briefly discuss ideal Carnot refrigeration cycle 2. General Refrigerant Characteristics 2.1. Stability, flammability, toxicity, corrosivity, cost, ozone depletion potential, global warming potential, COP, etc. 3. Refrigerant Possibilities 3.1. Ammonia, CFCs, halogenated hydrocarbons, hydrofluorocarbons, etc. 3.2 Comparison of at least 3 possibilities 4. Conclusions/Selection 5. References Appendix (include a schematic of a Carnot refrigeration cycle) Part 2: Perform the thermodynamic design calculations for an air-conditioning system for a specific automobile of your choosing (give the make, model, and year of the vehicle). DO NOT use a generic automobile. Your design should include only the thermodynamic aspects with a flow schematic showing anticipated temperatures, pressures, entropies, enthalpies, flow rates, heat loads, and work requirements, but the mechanical design (piping sizes, compressor parts, mounting mechanics, etc.) need not be Page 2 of 3 evaluated. Be sure to use the refrigerant you selected in Part 1 of this project. Include a copy of the graded Part 1 as an attachment to the final report. Discuss assumptions that you make, and give reasons that you made the assumptions. Determine how much cooling capacity is required to cool a specific car interior with full occupancy. Assume the highest temperature location in the U.S. and add another 5°C for the greenhouse effect when sunlight comes into a closed car on a hot summer day. Assume the metal, plastic, fabric, etc. in the car is heated to that temperature. Specify the weight of each component that will be cooled, how fast the interior should be cooled down and to what temperature everything should be cooled down to (except the people who will not be cooled down much below 98.6°F). Assume the refrigeration system is an ideal Carnot refrigerator. You should calculate the following: ? Cooling load which is needed to size the refrigeration system. Assume simple micp i (T2-T1) calculations for each material i to be cooled down. Assume no additional heat is added to those materials during the cooldown. ? Coolant flow rate to cool down the load in the selected time period ? wcompressor, QL, QH ? Coefficient of Performance for the refrigeration system If you choose a refrigerant that is in CATT, you may use it to calculate the refrigerant properties. Put a table in the Appendix of your report that includes: ? temperature ? pressure ? quality ? enthalpy ? entropy at each point in the cycle. This project will be a technical report for an engineering project. Part 2 should also include Part 1 with any recommended changes by the instructor. The final report should be completely integrated with both parts and should not have 2 separate parts, nor 2 sections labeled Part 1 and Part 2. The total maximum length is 7 pages including all figures and tables, but not including the cover page, the Table of Contents, the list of references, or Appendix. Example Outline: 1. Introduction Include a statement of the project and the scope of your work. 2. Discussion Include discussion regarding choice of refrigerant and other assumptions that you made to solve the problem. 3. Calculations Give a synopsis of the important aspects of the calculations. Don’t include too many details such as intermediate iterative calculations, but provide enough details so that your calculations could be checked for accuracy. 4. Schematic Page 3 of 3 General Specifications ? Must reference all sources in the body of the report (not just list them in the References) ? 12 point font, Times New Roman, single spacing, 1 inch margins all around ? All tables must have numbered captions above the table (e.g., Table 1. Comparison of refrigerants.) ? All figures must have numbered captions below the figure (e.g., Figure 1. Refrigeration schematic.) ? Number all equations [e.g., (1)] ? All figures, tables, and equations must be referenced in the report (i.e., you can’t have any figures, tables or equations that appear in the report but are not mentioned in the report) ? Use headings to separate different sections of the report ? Number all pages (1, 2, 3, . . .); the cover page is unnumbered; the Table of Contents is numbered as i ? Cite sources for any information, figures, or tables you did not create ? Don’t use person pronouns (e.g., I, we) – technical writing should be in the third person ? Put helpful but not necessary tables, figures, etc. in the Appendix ? Use SI units ? Watch the number of significant figures (if you include too many you will lose points) ? Show/discuss all assumptions ? If at all possible, don’t split a table over 2 pages. If the table is too long to fit on 1 page, then the table headings must be repeated again on every page where the table appears