Trainers and Technicians

A hydrocarbon (opens in a new window)is an organic compound consisting entirely of hydrogen and carbon. Propane (R290) and isobutane (R600a) are the most commonly used hydrocarbons today. They are mainly used as refrigerants for household appliances such as conventional refrigerators or domestic air conditioners, but also for commercial cooling in supermarkets.

CO₂ is neither toxic nor flammable and is used in a large number of cooling sectors such as commercial, industrial and transport refrigeration. However, due CO₂'s low critical point, additional components are needed for the refrigeration system. When designed properly, CO₂ can also be used in high temperature environments.

Learn more about CO₂'s properties and about its correct handling in the following videos.

Ammonia (NH₃) is mainly suitable for industrial and heavy commercial applications, such as large freezing and refrigeration plants. Even though ammonia has no long-term environmental effects, it is very toxic. Small leaks can be detected immediately because of its strong smell. With proper safety precautions it is the best choice for industrial refrigeration. 

Learn more about Ammonia as refrigerant R717 in the following video.

Water (H₂O) has been used as a refrigerant for thousands of years – whether in its liquid, gaseous or solid (ice) state. It is mainly used for evaporative cooling. How does it work? Water absorbs large amounts of heat in order to change from the liquid to the gaseous state (evaporation). As a result, the air temperature drops significantly when water evaporates.

Since ancient times, humans have been using air for ventilation and passive cooling of buildings in traditional wind towers (opens in a new window). It was also used on board ships for food refrigeration. In our days, it has been adapted, for example, for cabin cooling in planes, in German hi-tech trains (ICE 3), and for ultra-low-temperature applications (opens in a new window). 

One of the biggest advantages is that air does not need to be produced, as it is freely available everywhere. Moreover, the air-cycle systems used in the ICE trains have energy savings of up to 28% compared to the predominant R134a systems (see report (opens in a new window)by the German Environment Agency, UBA). Freeze-drying processes using air cycle refrigeration have demonstrated potential energy savings of up to 19% compared to traditional refrigerants like R404A (see report (opens in a new window)by euroammon). The higher investment costs of air-cycle systems are therefore compensated by lower operation costs, and by lower maintenance costs.