Building on the introductory framing, Yosr Allouche moves into a more application-focused discussion, illustrating how R290 is steadily expanding across multiple air-conditioning system types.
Part of the presentation.
© RACA Journal
Historically, hydrocarbons like R290 were often seen as suitable mainly for small, self-contained units – for example, certain domestic refrigerators or compact plug-in devices. That perception is now outdated.
Allouche presents evidence that R290 is advancing well beyond niche applications, entering a wide spectrum of room AC and heat pump systems, including:
- Split systems
- Ducted systems
- Chillers
- Even more complex arrangements like VRF (Variable Refrigerant Flow) systems
She explains why VRF systems are especially relevant in this context:
- VRF technology allows precise regulation of refrigerant flow, matching the specific cooling (and sometimes heating) demand of different zones or rooms.
- These systems can simultaneously provide cooling and heating to different spaces, optimising comfort and energy usage.
- Because the compressor can modulate instead of constantly cycling on and off, VRF systems reduce mechanical stress and improve efficiency.
- When VRF concepts are combined with R290, the result is a highly energy-efficient configuration that offers both operational flexibility and climate benefits.
However, this expansion is not without constraints. One of the crucial technical challenges Allouche underscores is the issue of refrigerant charge and charge limits, especially for flammable refrigerants:
- R290 is flammable, and wider adoption hinges on strictly managing charge size within safety standards.
- Charge limits are set by international and regional safety standards, and these limits often determine which system sizes and configurations can feasibly use R290.
- In many current systems, equipment was not originally optimised for minimum refrigerant charge, meaning there is still significant potential for design improvements.
She shares an important insight: in reversible RAC systems (providing both heating and cooling) with nominal cooling capacities below 12kW, the commonly used refrigerants today are R410A and R32. When comparing these synthetics with R290, two notable trends emerge:
- For a given cooling capacity, R290 often requires a lower specific charge than R32 or R410A.
- Within the capacity range up to about 12kW, as the capacity increases, the specific refrigerant charge required by R290 decreases.
These observations are significant because they highlight the technical feasibility of R290 and reinforce that there is room to optimise system design for:
- Lower refrigerant charge
- Higher safety margins
- Better energy performance
Allouche stresses that many current market systems are not yet optimised for charge reduction, implying that future generations of equipment could be safer, more efficient, and more competitive. She also calls for research and development to continue pushing the boundaries in:
- Heat exchanger design
- System architecture
- Leak risk mitigation
- Smart controls
At this point in the presentation, it becomes clear that technology itself is not the fundamental barrier. R290 is technically viable, and its applications are broadening. The next layer of complexity lies in the intersection of refrigerant choice, energy efficiency, and policy frameworks – which Allouche explores next, and can be read at RACA Journal online.
