Refrigeration Cycle: Interactive Simulation
This simulation was prepared using Mathematica. Download the free Wolfram player, and then download the simulation CDF file (link given below or click on figure to download). Try to predict the behavior when a parameter changes before using a slider to change that parameter. The screencast below explains how to use this simulation.
Pressure-enthalpy (P-H) and temperature-entropy (T-S) diagrams for refrigerant R-134a are used to demonstrate the ordinary vapor compression (OVC) cycle. You can vary the condenser pressure (high pressure) and the evaporator pressure (low pressure); the coefficient of performance (COP) is calculated for the cycle. The COP is the ratio of heat transferred from the cold reservoir Qc to the work W required to compress the gas in the compressor; a high value is desirable. Selecting “cycle” from the drop-down menu shows the components of the cycle, and moving the mouse over the circled numbers 1–4 on the cycle view displays the phases present at those points.
Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.
- How does the COP change when the condenser pressure decreases?
- How does the COP change when the evaporator pressure increases?