A cutting-edge study from the Technion-Israel Institute of Technology transforms how we think about power generation from renewable sources, particularly with low-temperature heat sources like geothermal and waste heat. Scientists at the Technion-Israel Institute of Technology have developed a 4E (Energy-Exergy-Economic-Environmental) model to evaluate eco-friendly zeotropic mixtures—combinations of natural gases including CO₂ and hydrocarbons—for use in Organic Rankine Cycles (ORC). This approach could drive energy efficiency and make renewable power both cheaper and greener.
Why CO₂ Matters in Power Cycles
Typical ORCs use synthetic fluids to capture heat, but these contribute to emissions and environmental damage due to high Global Warming Potential (GWP). In contrast, natural zeotropic mixtures—especially those using CO₂ combined with dimethyl ether (DME)—can offer cleaner, more efficient energy conversion. This study reveals that using CO₂-enhanced zeotropic mixtures achieves higher energy performance, with up to 50% more power generation than conventional fluids and drastically reduced energy losses.
A New Standard in System Design: Balancing Power, Compactness, and Cost
This research takes a unique perspective by balancing power efficiency, environmental impact, and cost. The team’s 4E model shows that using CO₂-based mixtures yields significant benefits for both energy efficiency and cost. By tailoring the amount of CO₂ in the mixture, the ORC can achieve the right balance between energy conversion and system compactness. This innovation not only drives up efficiency but also reduces the need for oversized equipment, making it more affordable and sustainable.
Future Implications for a Carbon-Neutral Power Grid
With the addition of CO₂, this zeotropic mixture approach promises to significantly enhance power systems using low-temperature heat sources, from geothermal to industrial waste heat. For countries seeking to meet ambitious climate targets, this breakthrough in eco-friendly ORCs could lead to widespread, cost-effective renewable energy adoption. The potential to harness wasted heat efficiently and with minimal emissions offers a compelling path forward for sustainable power generation worldwide.
Source
Techno-economic feasibility of CO2 utilization in sustainable energy harvesting: Energy-Exergy-Economic-Environmental (4E) analysis, Energy Conversion and Management: X, 2024-11-03
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