In this "dissecting" series of posts we will closely look at every problem in the NCEES "Sample Questions + Solutions" book. Today we start with the HVAC and Refrigeration sample questions. In the NCEES "Sample Questions + Solutions" book, the problems for the afternoon section are numbered 501 through 540. We begin our analysis with Problem 501.
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.