The second law of thermodynamics puts the first law into context and establishes entropy as a concept. We can simply define entropy as a state of disorder that can only increase or remain the same in natural processes. Processes in which entropy remains the same are reversible, but ones that result in an entropy […]

Many HVAC/R technicians (including me) describe the compressor as the heart of the refrigeration cycle. It prepares the refrigerant for the condensing process, which is crucial for heat rejection.  However, some refrigeration methods don’t require a compressor. In this article, we’ll look at those methods and their applications.   Gas movement without compressors As you […]

In residential air handler/fan coils, it is common to use a high-voltage interlock between the blower and the electric heat strips to ensure that the blower comes on whenever the heat is on. The problem is that it CANNOT work the other way around where the heat comes on with the blower. Heat strips are […]