Knowledge — Refrigeration Cycle

The refrigeration cycle is a critical component of HVAC systems and is governed by the principles of thermodynamics. Before we dive in, let’s get an understanding of four key concepts:

# 1: Heat of Vaporization

Knowledge — Superheat and Subcooling

Superheat and subcooling are critical to the refrigeration cycle, but can be tough concepts to visualize.

Let’s start with superheat:

Boiling is when a liquid gains heat and transforms into a vapor.

Equipment — Air Handling Units (AHU)

An air handling unit, or AHU, is a piece of HVAC equipment that is designed to regulate and circulate air throughout a space. Air handlers typically connect to a ductwork ventilation system that distributes the conditioned air throughout the building and returns it…

Equipment — Chillers

A chiller is designed to do one thing: make cold water for the facility’s air handlers. The amount and temperature is based on the application designed by the engineer. Like most things in HVAC, let’s think of chillers as a chain of heat absorption and rejection.

Knowledge — Tons

When it comes to measurements & scales, the United States is on a different page than the rest of the world. Other countries measure the capacity of an HVAC system in the form of BTU (British Thermal Units) per hour, while the US standard measurement is in Tons, or Tons of Refrigeration. Most HVAC…

Knowledge — High Voltage Side

The local power company supplies the power necessary for operation to what is known as the high voltage side of the HVAC unit. A contactor is present in the HVAC unit to allow the flow of electricity from the service breaker to the unit itself. It is quite literally what…

Knowledge — Low Voltage Side

HVAC units can autonomously control themselves on the low voltage side, also known as the control side, by powering on when cooling or heating is needed in the space. While there are many complex HVAC control systems, we will use the most basic controller — a thermostat — and a…