Refrigeration Principles

The science behind every refrigeration and air conditioning system, followed through a first-year apprentice at an HVAC-R contractor in Louisville: the trade and how refrigeration changed the world; matter, energy and conduction, convection and radiation; temperature scales, sensible and latent heat; gauge, absolute and vacuum pressure with manifolds and micron gauges; pressure-temperature charts and saturation; the vapor-compression cycle; superheat and subcooling; refrigerant families, ASHRAE 34 safety groups, GWP and the HFC phasedown; pressure-enthalpy diagrams and cycle COP; compressors, condensers, evaporators and metering devices; refrigeration loads, tons and Btu/h, COP and EER; and psychrometrics, air conditioning and the first tools of the trade, in US units.

RAC-110 12 lessons · 4 h 32 min ▶ Video lessons coming soon

Offered by HSM University · HVAC-R

This is the American version of this course. See the Canadian version.

What you'll learn

Describe the sectors and career paths of the HVAC-R trade and explain how refrigeration and its refrigerants developed, from natural ice to the Montreal Protocol and the Kigali Amendment
Explain matter, energy and the laws of thermodynamics, and calculate heat transfer by conduction, convection and radiation, including heat gain through insulated panels
Convert temperatures and temperature differences between scales, and calculate sensible and latent heat for heating, cooling, melting, freezing and boiling
Convert between gauge, absolute and vacuum pressures in SI and imperial units, and use manifolds, compound gauges and micron gauges correctly and safely
Use the pressure-temperature relationship and P-T charts, including interpolation, to find saturation temperatures, and explain saturation, glide and the critical point
Trace refrigerant around the vapor-compression cycle, naming its state and pressure at each point, and calculate refrigerating effect, flash gas and mass flow
Measure and calculate superheat and subcooling, and use them with pressures to recognize undercharge, overcharge, restriction and airflow patterns
Classify refrigerants by family, R-number and ASHRAE 34 safety group, compare their ODP and GWP, and explain the HFC phasedown and its effect on the trade
Read and plot a refrigeration cycle on a pressure-enthalpy diagram and calculate refrigerating effect, work, heat rejected and COP from enthalpies
Describe the types and functions of compressors, condensers, evaporators, metering devices and circuit accessories, and calculate compressor capacity and condenser airflow
Estimate a walk-in refrigeration load, convert between tons, Btu/h and kW, and calculate COP, EER, kW per ton and the Carnot limit
Use psychrometric properties and the psychrometric chart to analyze cooling and dehumidification, and select and check the first tools of the trade

Course content

12 lessons · 4 h 32 min total · final exam

1 The HVAC-R trade and how refrigeration changed the world 22 min · quiz
2 Matter, energy and heat transfer 26 min · quiz
3 Temperature, sensible heat and latent heat 25 min · quiz
4 Pressure, vacuum and gauges 24 min · quiz
5 Pressure-temperature relationships and saturation 22 min · quiz
6 The vapor-compression cycle 21 min · quiz
7 Superheat and subcooling introduced 22 min · quiz
8 Refrigerants: families, safety groups and the phasedown 22 min · quiz
9 Pressure-enthalpy diagrams and plotting the cycle 20 min · quiz
10 Compressors, condensers, evaporators and metering devices 23 min · quiz
11 Refrigeration load, capacity and system performance 24 min · quiz
12 Psychrometrics, air conditioning and first tools of the trade 21 min · quiz
E Final exam 20 questions

Requirements

TRD-102 Trade Math and Measurement

Recommended background. You can start any course at any time.