Modeling and Optimization of Complex Building Energy Systems with Deep Neural Networks

Modern buildings encompass complex dynamics of multiple electrical, mechanical, and control systems. One of the biggest hurdles in applying conventional model-based optimization and control methods to building energy management is the huge cost and effort of capturing diverse and temporally correlated dynamics. Here we propose an alternative approach which is model-free and data-driven. By utilizing high volume of data coming from advanced sensors, we train a deep Recurrent Neural Networks (RNN) which could accurately represent the operation's temporal dynamics of building complexes. The trained network is then directly fitted into a constrained optimization problem with finite horizons. By reformulating the constrained optimization as an unconstrained optimization problem, we use iterative gradient descents method with momentum to find optimal control inputs. Simulation results demonstrate proposed method's improved performances over model-based approach on both building system modeling and control

Materials and molecules for pollution free clean energy

La combustió dels combustibles fòssils ha causat problemes mediambientals i energètics a nivell mundial, la qual cosa influeix en la salut i les activitats humanes. Amb la motivació de contribuir per resoldre aquests problemes, hem realitzat una sèrie de recerques per explorar materials i molècules per a la generació d'energia lliure de contaminació, com és l'energia solar convertida en hidrogen que proposa aquesta tesi. Hem analitzat estadísticament les partícules contaminants en l'aire, partícules de PM2.5, les quals indiquen que els agregats de sutge rics en carboni mostren una adhesividad i agregació molt altes. Més del 50% de les partícules PM2.5 interactuen fortament amb el substrat generant una capa molt prima (<10 nm) la qual és molt estable (fins i tot sota estrès mecànic) i que està composta de metalls alcalins, hidrogen i grups CH. Després de l'estudi sobre partícules contaminants en l'aire, ens hem centrat en l'estudi de dispositius de divisió d'aigua mitjançant radiació solar per explorar la generació d'hidrogen a gran escala. En aquesta tesi, ens hem centrat principalment en la recerca de materials i molècules per a divisors de molècules d'aigua fotoelectroquímics (PEC) i fotovoltaic-electrolítics (PV-EC). Els nostres resultats mostren que en els dispositius PEC, poden dipositar-se en la superfície dels foto-ànodes de silici pel·lícules primes metàl·liques de coure i níquel, podent formar CuO i NiOX respectivament. Tots dos materials actuen com a catalitzadors molt actius per a la reacció d'oxidació d'aigua i alhora com una capa protectora de la corrosió per a superfície de silici. D'altra banda, els dispositius PV-EC, pels quals hem utilitzat un ànode basat en molècules catalizadoras de Ruteni, s'ha integrat amb cèl·lules solars d'unió triple. Aquests dispositius han aconseguit una eficiència màxima de conversió energia solar-hidrogen del 21,2% a pH neutre i just per sota de la il·luminació solar sense cap polarització externa. Aquests resultats contribueixen a la generació d'hidrogen per conversió solar a gran escala.La combustión de los combustibles fósiles ha causado problemas medioambientales y energéticos a nivel mundial, lo que influye en la salud y las actividades humanas. Con la motivación de contribuir para resolver estos problemas, hemos realizado una serie de investigaciones para explorar materiales y moléculas para la generación de energía libre de contaminación, como es la energía solar convertida en hidrógeno que propone esta tesis. Hemos analizado estadísticamente las partículas contaminantes en el aire, partículas de PM2.5, las cuales indican que los agregados de hollín ricos en carbono muestran una adhesividad y agregación muy altas. Más del 50% de las partículas PM2.5 interactúan fuertemente con el sustrato a través de una capa muy delgada (<10 nm) de trazas oscura la cual es muy estable incluso bajo estrés mecánico y está compuesta de metales alcalinos, hidrógeno y grupos CH. Después del estudio sobre partículas contaminantes en el aire, nos hemos centrado en el estudio de dispositivos de división de agua mediante radiación solar para explorar la generación de hidrógeno a gran escala. En esta tesis, nos hemos centrado principalmente en la investigación de materiales y moléculas para divisores de moléculas de agua fotoelectroquímicos (PEC) y fotovoltaico-electrolíticos (PV-EC). Nuestros resultados muestran que en los dispositivos PEC, pueden depositarse en la superficie de los foto-ánodos de silicio películas delgadas metálicas de cobre y níquel, pudiendo formar CuO y NiOX respectivamente. Ambos materiales actúan como catalizadores muy activos para la reacción de oxidación de agua y a la vez como una capa protectora de la corrosión para superficie de silicio. Por otro lado, los dispositivos PV-EC, para los que se usó un ánodo basado en moléculas catalizadoras de Rutenio, se ha integrado con células solares de unión triple comerciales. Estos dispositivos han logrado una eficiencia máxima de conversión energía solar-hidrógeno del 21,2% a pH neutro y justo por debajo de la iluminación solar sin ninguna polarización externa. Estos resultados allanan el camino para la generación de hidrógeno por conversión solar a gran escala.The combustion of the fossil fuels has caused the global environment and energy problems, which influences human health and activities. With the motivation to make our contributions to solving these problems, we have performed a series of investigations to explore materials and molecules for pollution free clean energy, which is solar energy converted hydrogen in this thesis. We have statistically analyzed the airborne pollutant particles, PM2.5 particles, which indicates that the carbon-rich fluffy soot aggregates always show very high adhesiveness and aggregation. And more than 50% PM2.5 particles strongly interact with the substrate through a ultra-thin (< 10 nm) dark trace layer, which is very stable even under mechanical stress and it is consisted of alkali metals, hydrogen and CH groups. After the study about airborne pollutant particles, we have moved to the study of solar-driven water splitting devices for exploring the large-scale generation of hydrogen. In this thesis, we have mainly focused on the investigation of the materials and molecules for photoelectrochemical (PEC) and photovoltaic-electrolysis (PV-EC) water splitting devices. Our results show that in the PEC water splitting devices, copper and nickel metallic thin films can be deposited on the surface of silicon photoanodes, which can form CuO and NiOX respectively and then serve as very active catalysts for water oxidation reaction and a protecting layer for silicon surface from corrosion. And in PV-EC water splitting devices, the ruthenium molecular catalysts based anode has been used for the electrolyzer, which has been integrated with commercially available triple junction solar cells. This integrated PV-EC device achieves the highest solar-to-hydrogen efficiency of 21.2 % at neutral pH and just under solar illumination without any external bias. These results pave the way for the generation of large-scale solar converted hydrogen

Crossed Beam Imaging Of The Reaction Dynamics Of Halogen Atoms With Selected Hydrocarbons

This dissertation presents results of applying dc slice imaging in crossed molecular beams to probe the dynamics of the reactions of halogen atoms (chlorine and fluorine) with polyatomic hydrocarbons and alcohols such as deuterated propanes, butane isomers, pentane, alkenes and propanol. The full velocity-flux contour maps of the radical products were measured with 157nm single photon ionization at various collision eneriges. Secondary and tertiary abstractions were found in Cl with normal and deuterated propanes and butane isomers and show distinct differences. The differences were explained in terms of the nature of abstraction sites, energy disposal of the radical product, and kinetic isotope effects. For Cl reaction with butene isomers, the coupling of translational energy and center of mass angular distributions reflect the energetics of competition between direct abstraction and addition/elimination pathways in accordance with ab initio thermochemical data. A possible Cl atom roaming mediating the indirect mechanism is suggested and further addressed with investigations of Cl + isobutene reactions at various collision energies. For reaction of chlorine atoms with butenes, the combined experimental theoretical calculations result shows that Cl addition-HCl elimination occurs from an abstraction-like Cl-H-C geometry, rather than a conventional three-center or four-center transition state. This geometry is accessed exclusively by Cl atom roaming from the initial adduct. For fluorine atom reaction with linear alkanes, i.e. propane, n-butane and n-pentane, little effect of reaction exoergicity appears in the reduced translational energy distributions. The fraction of available energy in translation for pentane is smaller than the other two. Sharp forward scattering were found in the center of mass angular distributions of all targets and the backscattering decreases in with the size of the molecule increasing. The analyzed data were compared with corresponding theoretical studies. For fluorine atom reaction with 1-propanol, the translational energy distribution and center of mass angular distributions is quite similar to the results of F + n-butane; it is possible that the greater fraction of collision energy in translation comes from the existence of O-H group. The product scattering distributions of fluorine reaction with 1-butene and 1-hexene provide evidence of a long-lived complex mediated mechanism

Using Battery Storage for Peak Shaving and Frequency Regulation: Joint Optimization for Superlinear Gains

We consider using a battery storage system simultaneously for peak shaving and frequency regulation through a joint optimization framework which captures battery degradation, operational constraints and uncertainties in customer load and regulation signals. Under this framework, using real data we show the electricity bill of users can be reduced by up to 15\%. Furthermore, we demonstrate that the saving from joint optimization is often larger than the sum of the optimal savings when the battery is used for the two individual applications. A simple threshold real-time algorithm is proposed and achieves this super-linear gain. Compared to prior works that focused on using battery storage systems for single applications, our results suggest that batteries can achieve much larger economic benefits than previously thought if they jointly provide multiple services.Comment: To Appear in IEEE Transaction on Power System

Optimal Regulation Response of Batteries Under Cycle Aging Mechanisms

When providing frequency regulation in a pay-for-performance market, batteries need to carefully balance the trade-off between following regulation signals and their degradation costs in real-time. Existing battery control strategies either do not consider mismatch penalties in pay-for-performance markets, or cannot accurately account for battery cycle aging mechanism during operation. This paper derives an online control policy that minimizes a battery owner's operating cost for providing frequency regulation in a pay-for-performance market. The proposed policy considers an accurate electrochemical battery cycle aging model, and is applicable to most types of battery cells. It has a threshold structure, and achieves near-optimal performance with respect to an offline controller that has complete future information. We explicitly characterize this gap and show it is independent of the duration of operation. Simulation results with both synthetic and real regulation traces are conducted to illustrate the theoretical results