Thermo project refrigeration

Department of Engineering and Physics ENGR 3203: Thermodynamics

Fall 2018 Class Project: Performance Analysis of a refrigerator with various

refrigerants You are a member of engineering design team, consists of three graduate engineers, of Central Thermo-Fluids Consulting Associates that has recently got a consultancy service on performance analysis of different refrigerants for a common households refrigerator (approximate capacity between 14 cft to 21 cft). As a team member , you need to perform a robust, independent and comprehensive performance analysis for a) various evaporator conditions (ex: COP vs evaporator temperature, cooling capacity vs evaporator temperature etc.), b) various condenser temperature and c) efficiency of compressor using i) first law and ii) second law analysis for at least 3 different types of refrigerants (ex. R134a, R410 etc.) where at least one of the refrigerants should be ‘green refrigerant or environment friendly’. A schematic (courtesy: Wikipedia) of a basic four component vapor compression cycle for an ideal refrigerator is shown below.

The accomplishment of the project will be done in two (2) parts. For each part you need to work as an independent member with consultation of your team member, incorporate their feedback (if they seem appropriate to you) and finally come up with a report and submit to your higher authority (i.e. to me).

Part 1: Your team will decide about the model number and brand of a common household refrigerator for which most of the technical information such as refrigerant, compressor/throttling pressure and temperature, condenser and evaporator operating conditions can be found. Also group members should do a rigorous independent study about the vapor compression cycle and its basic components, and collect (by doing research) specification/operating conditions (relevant to this job) for the basic four components i.e. compressor, evaporator, expansion/throttling device and condenser of your selected model refrigerator. As a team you are also required to do independent study on the refrigerants, their properties, selection criteria and US and international rules and regulation about the refrigerants and their usages. After performing an intensive study, you need to submit a report for this part. The content requirement of the part-1 report is given below. Submission: The report is due on Friday, November 9th at 10:00 am in class. The report is individual, however you can consult/discuss with your friends. Please write a report based on your study mentioned above and your report should address the followings.

1. What is vapor compression cycle? Describe each process of a basic vapor compression cycle with necessary schematics and energy equations.

2. What are the different types of compressor and throttling valves used in a refrigerators? Describe their advantages and disadvantages.

3. What are the different types of refrigerants used for refrigeration cycles? What are the desirable properties for an ideal refrigerant?

4. What are the international and USA rules and regulations regarding refrigerants? Decide about an environment friendly or so called ‘green or natural refrigerant’ and justify why this is environment friendly compared to a traditional refrigerant. What are the challenges in adopting natural refrigerants?

5. Find and list the required thermodynamic specifications (i.e. pressure, temperature, mass flow, power consumptions etc) of a vapor compression refrigerator components i.e. compressor, evaporator, condensers and throttling devices.

6. Find the thermodynamic tables of a natural refrigerant that you would use for your analysis in part-2 and provide the source with necessary website link or journal article link in the report.

Part 2: After collecting necessary information, you need to perform first law analysis of the refrigerator by considering all components are ideal, and generate results. Keep in mind that you may need to make necessary assumptions to conduct this study. If you do so, you need to justify those in your report. Also you need to perform second law analysis for all three refrigerant with a common operating conditions. Compare the performance of each refrigerator for a common operating conditions for all three refrigerants. Present report these results in a graph/table form in a report. Submission: A complete report that will contain executive summary, introduction, theory, results and discussion, conclusion and reference. The formatting guidelines of the report will be provided in the D2L with a sample report. This report is due on Friday, November 30th at 10 am in class.