# Engineering

Design Problem: Thermodynamic analysis of a refrigerant filling system
Background: XYZ Motor Corporation has decided to streamline their refrigerant filling assembly line operation by designing

a new compact refrigerant dispensing system. The new design will use the available refrigerant line pressure to force the

refrigerant to flow into the car on the assembly line, thereby eliminating the need for a elaborate and expensive

pressurization system. They have contracted with the AWS Engineering Consulting Corporation to design the new dispensing

system.
Problem Statement: The chief design engineer has placed you, a design engineer for AWS, on the compact refrigerant

dispensing design team. The fluid mechanics design engineer on your team needs to know the pressure in the car’s

refrigeration system as it is filled because the pressure difference between the factory’s refrigerant supply line and

car’s refrigerant system causes the refrigerant to flow into the car. The auto corporation has several different A/C

designs (i.e. various car refrigerant volume and mass sizes) and the dispensing system must work with all models.

Therefore, the fluid mechanics design engineer has requested that a computer program be developed that will give him the

pressure in the car’s refrigerant system as a function of supply conditions, volume and final refrigerant mass. Your

analysis will begin by solving a nominal system on paper. The nominal system constraints are a refrigerant supply of 200

psi and 80°F connected to an initially evacuated 154 in3 car refrigerant system. The air-conditioning system of the car is

designed to use 2 lbm of R134a.
Your initial analysis will determine the final pressure in the car’s refrigerant system. You will then develop a model

that will allow the supply conditions, final volume, and final mass to be varied with the refrigerant pressure in the car

as a function of mass determined for the specified initial conditions.
Your final report should include the following information in the main body: 1. Description of the method of solution

(including assumptions). 2. Plots of pressure versus mass for several different initial conditions. 3. Recommendations for

improving the model (i.e. assumptions to remove).
include in the Appendix: 1. Detailed hand calculations. 2. Computer output matching hand calculations. 3. Computer flow

chart. 4. Computer source code listing.
Presentation: Present your design problem solution in a brief written individual report. Include a Title Page, an

Introduction, a Results section containing written, graphical, or tabular results, a Discussion section, and Conclusions.
Results Section: State each result in narrative form and refer to each figure and table.
Discussion Section: Discuss the method of solution. Explain your logic. Clearly state and justify your assumptions. Make

recommendations for possible improvements

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