Description of Problem 501 : A schematic representation of a refrigeration system is provided. Some data regarding pressure and temperature at certain points are also provided. Thermodynamic properties for the refrigerant in the form of tables and a P-h diagram are provided. You are asked to calculate the coefficient of performance of the system.

Analysis Problem 501 : There is a lot of superfluous/unnecessary information provided in the problem statement that might distract you from the simple fact that what you need to calculate is the COP, which is easy stuff you did in thermo class back in the day. Here is a similar problem we have created (with some distracting/unnecessary data) to test the same concept:

HVAC&R Afternoon Section Problem #1: A refrigeration system for comfort air conditioning in a cruise ship operating with ammonia is schematically shown. The condenser is cooled with 450 gpm of seawater. A network of remotely located fan coil units (FCUs) uses chilled water-glycol provided by this system. You may neglect any pressure loss within the ammonia system.

In these series of posts, we will carefully look at all the problems in the NCEES “Sample Questions + Solutions” books.  Without disclosing the actual problem, we will analyze each one and propose an alternative problem similar in scope and difficulty either of our own design, or from the available literature. This analysis consistently reveals that the problems used in the afternoon portions of the Mechanical PE exam are no more difficult than anything you ever did as an engineering student. The feedback we receive from recent test takers is that the material and level of difficulty displayed in the NCEES "Sample Questions + Solutions" book is still a very good representation of what is in the actual test. Our aim is to shatter the myth of the tremendous difficulty that many people associate with the PE Exam. As you'll see, most of these problems are rather easy if you have prepared well.