Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids
Using pumps operating as turbines (PATs) offers the possibility of increasing the sustainability of water and energy systems by recovering the excess energy that would be otherwise lost in pressure-reducing valves or head loss chambers. Regarding on-grid applications, there have been many research w...
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| Format: | Article |
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MDPI AG
2024-03-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/17/6/1382 |
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| author | João M. R. Catelas João F. P. Fernandes Modesto Pérez-Sánchez P. Amparo López-Jiménez Helena M. Ramos P. J. Costa Branco |
| author_facet | João M. R. Catelas João F. P. Fernandes Modesto Pérez-Sánchez P. Amparo López-Jiménez Helena M. Ramos P. J. Costa Branco |
| author_sort | João M. R. Catelas |
| collection | DOAJ |
| description | Using pumps operating as turbines (PATs) offers the possibility of increasing the sustainability of water and energy systems by recovering the excess energy that would be otherwise lost in pressure-reducing valves or head loss chambers. Regarding on-grid applications, there have been many research works, and PATs have been implemented in several ways. However, more research still needs to be done on optimizing the efficiency and stability of PATs operating in off-grid systems. This work contributes to the development of stable direct current (DC) off-grid electric systems based on PATs using a self-excited induction generator (SEIG). In this context, a methodology is proposed, based on the hydraulic, mechanical, and electric subsystems, to define the PAT-SEIG operational area to maximize energy conversion and system efficiency. These limits depend highly on the capacitor value, rotational speed, and electric load. In addition, an analytical model is proposed to estimate the PAT-SEIG operation under specific conditions. With this, water managers can design and optimize an off-grid PAT-SEIG system and define the best hydraulic machines, electronic equipment, and control elements to maximize energy conversion within the target of operational limits. Two micro PAT-SEIG setups were implemented in the hydraulic laboratory of IST/CERIS under typical operating conditions to validate the proposed methodology. The system’s maximum efficiency and operational limits can be adapted using different capacitor values for the excitation of the SEIG. Considering the nominal efficiencies of the system’s components, the maximum p.u. efficiency obtained for each PAT-SEIG system was between 0.7 and 0.8 p.u. |
| first_indexed | 2024-04-24T18:21:39Z |
| format | Article |
| id | doaj.art-bb8029c41e144c789ffa515c52c44746 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-24T18:21:39Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-bb8029c41e144c789ffa515c52c447462024-03-27T13:35:36ZengMDPI AGEnergies1996-10732024-03-01176138210.3390/en17061382Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-GridsJoão M. R. Catelas0João F. P. Fernandes1Modesto Pérez-Sánchez2P. Amparo López-Jiménez3Helena M. Ramos4P. J. Costa Branco5Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalIDMEC, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalHydraulic and Environmental Engineering Department, Universitat Politècnica de València, 46022 Valencia, SpainHydraulic and Environmental Engineering Department, Universitat Politècnica de València, 46022 Valencia, SpainDepartment of Civil Engineering, Architecture and Environment, CERIS, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalIDMEC, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, PortugalUsing pumps operating as turbines (PATs) offers the possibility of increasing the sustainability of water and energy systems by recovering the excess energy that would be otherwise lost in pressure-reducing valves or head loss chambers. Regarding on-grid applications, there have been many research works, and PATs have been implemented in several ways. However, more research still needs to be done on optimizing the efficiency and stability of PATs operating in off-grid systems. This work contributes to the development of stable direct current (DC) off-grid electric systems based on PATs using a self-excited induction generator (SEIG). In this context, a methodology is proposed, based on the hydraulic, mechanical, and electric subsystems, to define the PAT-SEIG operational area to maximize energy conversion and system efficiency. These limits depend highly on the capacitor value, rotational speed, and electric load. In addition, an analytical model is proposed to estimate the PAT-SEIG operation under specific conditions. With this, water managers can design and optimize an off-grid PAT-SEIG system and define the best hydraulic machines, electronic equipment, and control elements to maximize energy conversion within the target of operational limits. Two micro PAT-SEIG setups were implemented in the hydraulic laboratory of IST/CERIS under typical operating conditions to validate the proposed methodology. The system’s maximum efficiency and operational limits can be adapted using different capacitor values for the excitation of the SEIG. Considering the nominal efficiencies of the system’s components, the maximum p.u. efficiency obtained for each PAT-SEIG system was between 0.7 and 0.8 p.u.https://www.mdpi.com/1996-1073/17/6/1382energy efficiencymicro-hydropowerpump-as-turbine (PAT)off-gridself-excited induction generator (SEIG)water–energy nexus |
| spellingShingle | João M. R. Catelas João F. P. Fernandes Modesto Pérez-Sánchez P. Amparo López-Jiménez Helena M. Ramos P. J. Costa Branco Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids Energies energy efficiency micro-hydropower pump-as-turbine (PAT) off-grid self-excited induction generator (SEIG) water–energy nexus |
| title | Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids |
| title_full | Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids |
| title_fullStr | Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids |
| title_full_unstemmed | Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids |
| title_short | Energy Efficiency and Stability of Micro-Hydropower PAT-SEIG Systems for DC Off-Grids |
| title_sort | energy efficiency and stability of micro hydropower pat seig systems for dc off grids |
| topic | energy efficiency micro-hydropower pump-as-turbine (PAT) off-grid self-excited induction generator (SEIG) water–energy nexus |
| url | https://www.mdpi.com/1996-1073/17/6/1382 |
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