The purpose of this article is to provide a simple explanation of these terms for those who desire a concise understanding as well as a review for those who understand the terms but want to take another look. An understanding of these terms and the concepts related to them is essential to understanding the air conditioning and refrigeration mechanical-refrigerant cycle as well as being necessary to troubleshooting problems.
Most materials can exist in three forms: solids, liquids, and gases. Water is a common example. Water can exist as a solid (ice), a liquid, or a gas or vapor (steam). Only a gas or vapor (these are interchangeable terms) can be superheated. Let's use water as an example as we explain these terms.