Optimizing Grids Demand Reduction through Enhanced Heat Transfer in Low-Temperature Waste Heat Driven ORC Systems
- 1 Shanghai Leadership Refrigeration Technology Company, Shanghai, China
- 2 Institute of Refrigeration and Cryogenic, Shanghai Jiao Tong University, Shanghai, China
Abstract
With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, waste incineration heat, and renewable energy sources such as geothermal heat, biomass energy, and solar energy at lower temperatures. However, the low-grade heat source utilized in ORC systems faces a challenge to achieving high power generation efficiency and output power. Therefore, enhancing the power generation capacity of ORC systems is a key research focus in this field. An entranced heat exchanger ORC system with the screw expander driven by the low-temperature heat source is established to investigate the relevant performance. Hot water temperature from 77°C to 132 ° C is adopted for performance analysis, while the environmental temperature is approximately 25 ° C. Refrigerant R245fa is selected as the working fluid, and the screw expander is employed for power generation. It is worth noting that the entranced heat exchanger ORC system has significant potential for low-temperature heat recovery. Experimental results indicate that the maximum power output is 12.83 kW, which is obtained at around 105 ° C hot water inlet temperature. Correspondingly, the average power output remains 11.75 kW, revealing the system’s high stability for power generation. The implementation of a plate heat exchanger for enhanced heat transfer has enabled a 50% reduction in system size compared to traditional shell-tube type ORC systems. Besides, economic calculations demonstrate substantial benefits associated with the ORC system. The calculations indicate an internal benefit of 560,000 RMB/year, accompanied by notable external benefits such as an energy saving and emission reduction potential of up to 784 t CO2 per year. Moreover, the payback period is 2.23 years. It shows a remarkable improvement in terms of performance and excellent economic benefits. As a result, the novel ORC presents a promising alternative for low-grade heat utilization as compared to conventional small-scale ORC systems.
- Ozcan, Z. and Ekici, O. (2021) A Novel Working Fluid Selection and Waste Heat Recovery by an Exergoeconomic Approach for a Geothermally Sourced ORC System. Geothermics, 95, Article 102151. https://doi.org/10.1016/j.geothermics.2021.102151
- Braimakis, K., Charalampidis, A. and Karellas, S. (2021) Techno-Economic Assessment of a Small-Scale Biomass ORC-CHP for District Heating. Energy Conversion and Management, 247, Article 114705. https://doi.org/10.1016/j.enconman.2021.114705
- Alvi, J.Z., Imran, M., Pei, G., Li, J., Gao, G. and Alvi, J. (2017) Thermodynamic Comparison and Dynamic Simulation of Direct and Indirect Solar Organic Rankine Cycle Systems with PCM Storage. Energy Procedia, 129, 716-723. https://doi.org/10.1016/j.egypro.2017.09.103
- Li, J., Pei, G., Li, Y. and Ji, J. (2011) Evaluation of External Heat Loss from a Small-Scale Expander Used in Organic Rankine Cycle. Applied Thermal Engineering, 31, 2694-2701. https://doi.org/10.1016/j.applthermaleng.2011.04.039
- Dumont, O., Talluri, L., Fiaschi, D., Manfrida, G. and Lemort, V. (2019) Comparison of a Scroll, A Screw, A Roots, A Piston Expander and a Tesla Turbine for Small-Scale Organic Rankine Cycle. 5th International Seminar on ORC Power Systems, Athens, 9-11 September 2019.
- Thurairaja, K., Wijewardane, A., Jayasekara, S. and Ranasinghe, C. (2019) Working Fluid Selection and Performance Evaluation of ORC. Energy Procedia, 156, 244-248. https://doi.org/10.1016/j.egypro.2018.11.136
- Eyerer, S., Dawo, F., Kaindl, J., Wieland, C. and Spliethoff, H. (2019) Experimental Investigation of Modern ORC Working Fluids R1224yd(Z) and R1233zd(E) as Replacements for R245fa. Applied Energy, 240, 946-963. https://doi.org/10.1016/j.apenergy.2019.02.086
- Imran, M., Usman, M., Park, B.-S., Kim, H.-J. and Lee, D.-H. (2015) Multi-Objective Optimization of Evaporator of Organic Rankine Cycle (ORC) for Low Temperature Geothermal Heat Source. Applied Thermal Engineering, 80, 1-9. https://doi.org/10.1016/j.applthermaleng.2015.01.034
- Zhang, X., Wang, L., Wang, Z., Wang, L. and Zhang, Z. (2022) Non-Steady Thermodynamic Characteristics of a Pilot-Scale Organic Rankine Cycle System with a Thermally-Driven Pump. Energy, 252, Article 123993. https://doi.org/10.1016/j.energy.2022.123993