All images © RACA Journal www. refrigerationandaircon. co. za RACA Journal I September 2025 13
Events and Exhibitions
BATTLING GLOBAL WARMING: ENHANCING EFFICIENCY AND LONGEVITY IN HYDRONIC SYSTEMS
By Eamonn Ryan
Luigi Rossettini, a director of Aermec S. p. A., delivered a presentation at FRIGAIR 2025, stressing the urgent need to address global warming through efficient hydronic system design.
His talk,‘ Global warming routes: how to enhance efficiency in hydronic systems granting long working life of the equipment’, emphasised the critical role of the HVAC industry in reducing CO2 emissions and ensuring sustainable solutions for future generations.
Rossettini began by highlighting the undeniable reality of global warming, emphasising that rising global temperatures are a scientifically proven fact. He pointed to two primary sources of CO2 emissions from the HVAC sector:
• Direct emissions: Resulting from refrigerants used in units, particularly those with high Global Warming Potential( GWP). GWP is an index quantifying the damage one kilogram of refrigerant released into the environment causes; for instance, one kilogram of R410A refrigerant generates the equivalent of 2 000kg of CO2.
• Indirect emissions: Stemming from the energy consumption of HVAC equipment. Rossettini noted that in South Africa, every kilowatt-hour of energy consumed indirectly generates a significant 0.79 kilograms of CO2, a notably high value.
" The responsibility lies with us, the consultants and designers, to consider both direct and indirect effects. The European Union has already mandated the use of natural refrigerants or those with low GWP by 2030, which is a clear signal of the global shift. To comprehensively assess environmental impact, I introduced the Total Warm Environmental Impact( TEWI) index, a
“ To mitigate short cycling, Rossettini recommended designing with multiple, smaller units in parallel.” straightforward calculation that factors in both the mass of refrigerant and its GWP, alongside the energy consumed over the unit ' s estimated lifespan," said Rossettini.
DESIGNING FOR LONGEVITY AND EFFICIENCY Rossettini stressed that newly designed hydronic systems should aim for a working life of at least 15 to 20 years. This longevity is crucial not only for economic reasons but also for environmental stewardship, as proper refrigerant recovery at the end of a unit ' s life often falls short, leading to harmful atmospheric releases.
To optimise hydronic systems for both efficiency and extended operational life, he outlined several key considerations:
• Relying solely on nominal data like EER or COP is insufficient, and a holistic approach is required
• Proper Building Management System( BMS) control is fundamental: Rossettini warned that incorrect control can reduce system efficiency by as much as 30 %
• During commissioning, the pumping system must be carefully adjusted to align with the average or minimum flow requirements of the units. This adjustment significantly reduces pumping energy and saves costs. Rossettini strongly advocated for professional commissioning to ensure units are optimized for peak performance
Luigi Rossettini, a director of Aermec S. p. A., delivered a presentation at FRIGAIR 2025.
• Comprehensive understanding of cooling loads, heating loads, domestic hot water production and fresh air requirements is essential for accurate system sizing and design
All images © RACA Journal www. refrigerationandaircon. co. za RACA Journal I September 2025 13