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Improvement in Heat Transfer in Hydrocarbon and Geothermal Energy Coproduction Systems Using Carbon Quantum Dots: An
Yurany Villada1, Lady J Giraldo1, Diana Estenoz2
1Grupo de Investigación Fenómenos de Superficie Michael Polanyi, Departamento de Procesos y Energía, Facultad de Minas, Universidad Nacional de Colombia, Sede Medellín, Medellín 050034, Colombia.
Nanomaterials (Basel, Switzerland)
|June 25, 2025
Summary
Carbon quantum dots (CQDs) enhance heat transfer in energy coproduction systems. CQDs in nanofluids boost thermal conductivity and organic Rankine cycle efficiency, improving oil and electrical energy output from depleted wells.
Area of Science:
- Energy Engineering
- Materials Science
- Nanotechnology
Background:
- Hydrocarbon and geothermal energy coproduction systems face challenges in efficient heat transfer from depleted wells.
- Optimizing heat transfer is crucial for maximizing oil and electrical energy output.
Purpose of the Study:
- To improve heat transfer in energy coproduction systems using carbon quantum dots (CQDs).
- To evaluate the impact of CQDs on nanofluid thermophysical properties and organic Rankine cycle (ORC) efficiency.
Main Methods:
- Synthesized and commercial CQDs were characterized for properties like size, zeta potential, and heat capacity.
- Nanofluids were prepared using oil well brine and CQDs at various concentrations (100-1000 mg/L).
- Thermal conductivity was measured, and a mathematical model was developed to predict nanofluid effects on ORC efficiency.
Main Results:
- CQD addition (up to 500 mg/L) significantly increased nanofluid thermal conductivity by up to 60%.
- A concentration of 1000 mg/L led to decreased thermal conductivity due to nanoparticle aggregation.
- The developed model accurately predicted thermal conductivity and cycle efficiency based on CQD concentration and brine salinity.
Conclusions:
- CQDs are effective in enhancing thermal conductivity of nanofluids for energy coproduction.
- Optimal CQD concentrations (approx. 550 mg/L) can increase ORC efficiency by up to 18.6%.
- This research offers a pathway to improved energy recovery from depleted oil and geothermal wells.
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