SIC - Sistemes Intel·ligents de Control
http://hdl.handle.net/2117/22168
2019-12-15T19:25:57ZRobust fault detection of non-linear systems using set-membership state estimation based on constraint satisfaction
http://hdl.handle.net/2117/172739
Robust fault detection of non-linear systems using set-membership state estimation based on constraint satisfaction
Tornil Sin, Sebastián; Ocampo-Martínez, Carlos; Puig Cayuela, Vicenç; Escobet Canal, Teresa
In this paper, the robust fault detection problem for non-linear systems considering both bounded parametric modelling errors and measurement noises is addressed. The non-linear system is monitored by using a state estimator with bounded modelling uncertainty and bounded process and measurement noises. Additionally, time-variant and time-invariant system models are taken into account. Fault detection is formulated as a set-membership state estimation problem, which is implemented by means of constraint satisfaction techniques. Two solutions are presented: the first one solves the general case while the second solves the time-variant case, being this latter a relaxed solution of the first one. The performance of the time-variant approach is tested in two applications: the well-known quadruple-tank benchmark and the dynamic model of a representative portion of the Barcelona's sewer network. In both applications, different scenarios are presented: a faultless situation and some faulty situations. All considered scenarios are intended to show the effectiveness of the presented approach.
2019-11-20T12:01:23ZTornil Sin, SebastiánOcampo-Martínez, CarlosPuig Cayuela, VicençEscobet Canal, TeresaIn this paper, the robust fault detection problem for non-linear systems considering both bounded parametric modelling errors and measurement noises is addressed. The non-linear system is monitored by using a state estimator with bounded modelling uncertainty and bounded process and measurement noises. Additionally, time-variant and time-invariant system models are taken into account. Fault detection is formulated as a set-membership state estimation problem, which is implemented by means of constraint satisfaction techniques. Two solutions are presented: the first one solves the general case while the second solves the time-variant case, being this latter a relaxed solution of the first one. The performance of the time-variant approach is tested in two applications: the well-known quadruple-tank benchmark and the dynamic model of a representative portion of the Barcelona's sewer network. In both applications, different scenarios are presented: a faultless situation and some faulty situations. All considered scenarios are intended to show the effectiveness of the presented approach.Enhanced equal frequency partition method for the identification of a water demand system
http://hdl.handle.net/2117/172308
Enhanced equal frequency partition method for the identification of a water demand system
Escobet Canal, Antoni; Huber Garrido, Rafael M.; Nebot Castells, M. Àngela; Cellier, François E.
This paper deals with unsupervised partitioning. A first goal of this paper is to present an enhancement to the Equal Frequency Partition (EFP) method that allows to reduce, to some extent, the main drawback of this classical classification method, i.e. the data distribution dependency. A second goal of this work is to use the Enhanced Equal Frequency Partition (EEFP) method within the discretization process of the Fuzzy Inductive Reasoning (FIR) methodology for the identification of a model of a water demand system. It is shown that use of the EEFP method allows to obtain more accurate FIR models of the water demand system, reducing the prediction errors.
2019-11-13T12:47:16ZEscobet Canal, AntoniHuber Garrido, Rafael M.Nebot Castells, M. ÀngelaCellier, François E.This paper deals with unsupervised partitioning. A first goal of this paper is to present an enhancement to the Equal Frequency Partition (EFP) method that allows to reduce, to some extent, the main drawback of this classical classification method, i.e. the data distribution dependency. A second goal of this work is to use the Enhanced Equal Frequency Partition (EEFP) method within the discretization process of the Fuzzy Inductive Reasoning (FIR) methodology for the identification of a model of a water demand system. It is shown that use of the EEFP method allows to obtain more accurate FIR models of the water demand system, reducing the prediction errors.Gas film heat transfer as enhancement strategy for phase change materials
http://hdl.handle.net/2117/170818
Gas film heat transfer as enhancement strategy for phase change materials
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
In this work, consideration is given to an alternative strategy for phase change materials (PCMs) heat transfer enhancement with particular reference to horizontal plates. In contrast with current approaches in which heat transfer enhancement is pursued either by adapted geometries or acting on the thermal conductivity coefficient of a given PCM, here the problem is tackled by preventing the formation and contact of the front of solidification at the wall of the vessel by the deliberate presence of a gas film between the wall and the PCM. Because the presence of such a film, the front of solidification only can attains a certain critical thickness before gravitationally sinks by its own weight and then eliminating the continuous growth of the solid layer with the consequent reduction of conductive heat transfer and power output of the system as the solidification takes place which translates into an enhanced and steady power during the entire solidification process. It is shown that because the critical thickness of the solidified layer before sinks is a few millimeters or less and then smaller than practical gas films, therefore the heat transfer is controlled by the thickness and the thermal conductivity of the film. Additional R&D is required in order to arrive at a reliable practical and safe design
2019-10-24T14:24:34ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasIn this work, consideration is given to an alternative strategy for phase change materials (PCMs) heat transfer enhancement with particular reference to horizontal plates. In contrast with current approaches in which heat transfer enhancement is pursued either by adapted geometries or acting on the thermal conductivity coefficient of a given PCM, here the problem is tackled by preventing the formation and contact of the front of solidification at the wall of the vessel by the deliberate presence of a gas film between the wall and the PCM. Because the presence of such a film, the front of solidification only can attains a certain critical thickness before gravitationally sinks by its own weight and then eliminating the continuous growth of the solid layer with the consequent reduction of conductive heat transfer and power output of the system as the solidification takes place which translates into an enhanced and steady power during the entire solidification process. It is shown that because the critical thickness of the solidified layer before sinks is a few millimeters or less and then smaller than practical gas films, therefore the heat transfer is controlled by the thickness and the thermal conductivity of the film. Additional R&D is required in order to arrive at a reliable practical and safe designOn the feasibility of ocean brine pool power stations
http://hdl.handle.net/2117/170786
On the feasibility of ocean brine pool power stations
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
The demonstrated existence of vast brine pools in a number of places in the ocean basin around the world offers an interesting opportunity to the production of power from ocean, which has not been yet considered. The attractiveness of these vast deposits of brine lie in the fact that can be readily dissolved with the surrounding top waters extracting the spontaneous osmotic mixing energy released. In addition, osmotic engines can pumped out the brackish streams by buoyancy without the add of pressure exchangers (PEXs) as is required in current pressure retarded osmosis (PRO) technology and then simplifying significatively the overall process. Utilizing a simplified physical model, a first estimation for the density of power per unit of membrane area was calculated
2019-10-24T11:55:47ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasThe demonstrated existence of vast brine pools in a number of places in the ocean basin around the world offers an interesting opportunity to the production of power from ocean, which has not been yet considered. The attractiveness of these vast deposits of brine lie in the fact that can be readily dissolved with the surrounding top waters extracting the spontaneous osmotic mixing energy released. In addition, osmotic engines can pumped out the brackish streams by buoyancy without the add of pressure exchangers (PEXs) as is required in current pressure retarded osmosis (PRO) technology and then simplifying significatively the overall process. Utilizing a simplified physical model, a first estimation for the density of power per unit of membrane area was calculatedAn estimate for thermal osmotic heat storage using precipitation of common salts
http://hdl.handle.net/2117/169539
An estimate for thermal osmotic heat storage using precipitation of common salts
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
In this brief note, a first assessment on the possibilities for thermal osmotic storage by harnessing the thermal dependence of the solubility of common salts as an alternative method to sensible heat storage is discussed. In a recent study it was found that such a dependence could be used to run a heat powered cycle (osmotic heat engine). The question raised then is whether that approach could be suitable for thermal energy storage as well. The attractiveness of such a possibility lies in the capability to store energy for an indefinite period of time without using expensive isolation systems if one considers that osmotic energy only is released when both streams with different salinities are brought together. Utilizing a simplified model, a comparative study with sensible heat storage was performed. It is shown that thermal osmotic storage via thermal precipitation of common salts could be an attractive option when long thermal storage (days) and compactness is desired
2019-10-09T13:14:40ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasIn this brief note, a first assessment on the possibilities for thermal osmotic storage by harnessing the thermal dependence of the solubility of common salts as an alternative method to sensible heat storage is discussed. In a recent study it was found that such a dependence could be used to run a heat powered cycle (osmotic heat engine). The question raised then is whether that approach could be suitable for thermal energy storage as well. The attractiveness of such a possibility lies in the capability to store energy for an indefinite period of time without using expensive isolation systems if one considers that osmotic energy only is released when both streams with different salinities are brought together. Utilizing a simplified model, a comparative study with sensible heat storage was performed. It is shown that thermal osmotic storage via thermal precipitation of common salts could be an attractive option when long thermal storage (days) and compactness is desiredThe use of compliant surfaces for harvesting energy from water streams
http://hdl.handle.net/2117/168440
The use of compliant surfaces for harvesting energy from water streams
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
The possibility for hydrokinetic energy harvesting from small water streams by using compliant surfaces is considered. The basis of the proposed idea is the deliberate bifurcation of a water stream into two streams separated by a compliant or membrane surface keeping an equalized static pressure in both sides but, however, with a relative velocity between both channels. Then, owing to this relative velocity of the water stream Taylor instabilities appear which set in oscillatory motion the membrane. This motion can be converted into a small electrical output power. Utilizing a linearized flow theory an analytical expression for the attainable power as function of several parameters was derived. Actual experimental investigations were undertaken which show a good agreement with the theoretical predictions. It was found that for a water stream with velocity around 2¿m/s an output power around 30 mW/cm 2 of area of the membrane is attainable. Because large areas can be covered inexpensively by the use of membranes, the concept is worthy to be considered for hydropower harvesting in water flows which are not suitable to be turbined either because a reduced pressure or little depth which prevents the use of turbines. Additional R&D is required in order to arrive at a reliable practical and commercial design
2019-09-19T12:50:18ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasThe possibility for hydrokinetic energy harvesting from small water streams by using compliant surfaces is considered. The basis of the proposed idea is the deliberate bifurcation of a water stream into two streams separated by a compliant or membrane surface keeping an equalized static pressure in both sides but, however, with a relative velocity between both channels. Then, owing to this relative velocity of the water stream Taylor instabilities appear which set in oscillatory motion the membrane. This motion can be converted into a small electrical output power. Utilizing a linearized flow theory an analytical expression for the attainable power as function of several parameters was derived. Actual experimental investigations were undertaken which show a good agreement with the theoretical predictions. It was found that for a water stream with velocity around 2¿m/s an output power around 30 mW/cm 2 of area of the membrane is attainable. Because large areas can be covered inexpensively by the use of membranes, the concept is worthy to be considered for hydropower harvesting in water flows which are not suitable to be turbined either because a reduced pressure or little depth which prevents the use of turbines. Additional R&D is required in order to arrive at a reliable practical and commercial designA first estimate for thermal osmotic long storage
http://hdl.handle.net/2117/168360
A first estimate for thermal osmotic long storage
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
In this brief note, a first assessment on the possibilities for thermal osmotic storage using the thermal precipitation of aqueous solutions as alternative to sensible heat storage is performed. In a recent study it was found that the thermal dependence of the solubility of many common aqueous solutions could be harnessed to transform thermal energy into osmotic energy and then to run a heat powered cycle. Here, a scoping study is performed on the possibility to use such a property to storage thermal energy. Utilizing a transient model it was found that despite the fact that traditional sensible heat can stores much more thermal energy than osmotic does, however, for large Biot and Fourier numbers -which means compactness and long thermal storage, the osmotic storage becomes an attractive option. Additional R&D is required in order to arrive at a reliable practical and commercial design
2019-09-18T11:00:38ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasIn this brief note, a first assessment on the possibilities for thermal osmotic storage using the thermal precipitation of aqueous solutions as alternative to sensible heat storage is performed. In a recent study it was found that the thermal dependence of the solubility of many common aqueous solutions could be harnessed to transform thermal energy into osmotic energy and then to run a heat powered cycle. Here, a scoping study is performed on the possibility to use such a property to storage thermal energy. Utilizing a transient model it was found that despite the fact that traditional sensible heat can stores much more thermal energy than osmotic does, however, for large Biot and Fourier numbers -which means compactness and long thermal storage, the osmotic storage becomes an attractive option. Additional R&D is required in order to arrive at a reliable practical and commercial designPumps condition assessment in water distribution networks
http://hdl.handle.net/2117/166232
Pumps condition assessment in water distribution networks
Soldevila, Adrià; Blesa Izquierdo, Joaquim; Fernández Canti, Rosa M.; Tornil Sin, Sebastián; Meseguer Amela, Jordi; Puig Cayuela, Vicenç
2019-07-15T12:00:13ZSoldevila, AdriàBlesa Izquierdo, JoaquimFernández Canti, Rosa M.Tornil Sin, SebastiánMeseguer Amela, JordiPuig Cayuela, VicençSlingshot resonance for ocean wave energy conversion
http://hdl.handle.net/2117/135390
Slingshot resonance for ocean wave energy conversion
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
The slingshot effect and its application to converting ocean wave energy are discussed. It is shown that, owing to the large inertia transported by ocean waves and their periodicity, the slingshot effect can result in the transmission of significant kinetic energy to a puck colliding elastically with a pusher plate driven by ocean wave motion. A simplified geometrical model is used to demonstrate that, despite the stochastic nature of the collisions (whereby collisions occur at random times in the wave cycle), head-on collisions occur more frequently, yielding a net average gain of energy. However, the most promising configuration for applying the slingshot effect to ocean wave energy conversion is that which matches, through appropriate design, the travel time of the puck between collisions with the wave period. Then, only head-on collisions occur, resulting in a significant magnification of the puck kinetic energy. Further research will be required before this slingshot effect can be practically implemented for ocean wave energy conversion
2019-06-26T09:44:08ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasThe slingshot effect and its application to converting ocean wave energy are discussed. It is shown that, owing to the large inertia transported by ocean waves and their periodicity, the slingshot effect can result in the transmission of significant kinetic energy to a puck colliding elastically with a pusher plate driven by ocean wave motion. A simplified geometrical model is used to demonstrate that, despite the stochastic nature of the collisions (whereby collisions occur at random times in the wave cycle), head-on collisions occur more frequently, yielding a net average gain of energy. However, the most promising configuration for applying the slingshot effect to ocean wave energy conversion is that which matches, through appropriate design, the travel time of the puck between collisions with the wave period. Then, only head-on collisions occur, resulting in a significant magnification of the puck kinetic energy. Further research will be required before this slingshot effect can be practically implemented for ocean wave energy conversionHydrokinetic energy conversion using compliant surfaces
http://hdl.handle.net/2117/135356
Hydrokinetic energy conversion using compliant surfaces
Arias Montenegro, Francisco Javier; Heras Jiménez, Salvador Augusto de las
In this work, consideration is given for a novel technology based on the use of compliant surfaces (membranes) for hydrokinetic energy conversion (HEC) from residual waters where the use of traditional turbines is either not possible or strongly limited. Here, residual waters are understood as waters with a small total pressure difference relative to the surrounding environment that are not suitable to be turbined. Such waters encompass not only domestic or industrial waste water before being discharged into the sewer but also typical flows found in river waterways of small depth or even postturbined water. In summary, the proposed technology is based on the deliberated bifurcation of residual water into two streams separated by a compliant surface or membrane that equalizes the static pressure in both streams and also generates a relative velocity between them. As a result, Taylor instabilities translate into the oscillatory motion of the membrane, which can be transformed into output power. Utilizing linearized flow theory, an analytical expression for the extractable density power is derived. Experiments are carried out for a rectangular membrane, and the data obtained are quantitatively and qualitatively in good agreement with the theoretical model, where it is found that for typical residual water with a velocity of approximately 1.7 m/s, the output power density is on the order of 30 mW/cm2 based on the area of the membrane. Additional research and development is required to arrive at a reliable practical and commercial design
2019-06-25T12:55:25ZArias Montenegro, Francisco JavierHeras Jiménez, Salvador Augusto de lasIn this work, consideration is given for a novel technology based on the use of compliant surfaces (membranes) for hydrokinetic energy conversion (HEC) from residual waters where the use of traditional turbines is either not possible or strongly limited. Here, residual waters are understood as waters with a small total pressure difference relative to the surrounding environment that are not suitable to be turbined. Such waters encompass not only domestic or industrial waste water before being discharged into the sewer but also typical flows found in river waterways of small depth or even postturbined water. In summary, the proposed technology is based on the deliberated bifurcation of residual water into two streams separated by a compliant surface or membrane that equalizes the static pressure in both streams and also generates a relative velocity between them. As a result, Taylor instabilities translate into the oscillatory motion of the membrane, which can be transformed into output power. Utilizing linearized flow theory, an analytical expression for the extractable density power is derived. Experiments are carried out for a rectangular membrane, and the data obtained are quantitatively and qualitatively in good agreement with the theoretical model, where it is found that for typical residual water with a velocity of approximately 1.7 m/s, the output power density is on the order of 30 mW/cm2 based on the area of the membrane. Additional research and development is required to arrive at a reliable practical and commercial design