• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 2
  • 2
  • Tagged with
  • 19
  • 19
  • 9
  • 6
  • 5
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Energy Management in Large scale Solar Buildings : The Closed Greenhouse Concept

Vadiee, Amir January 2013 (has links)
Sustainability has been at the centre of global attention for decades. One of the most challenging areas toward sustainability is the agricultural sector. Here, the commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times higher than for open land farming. However, this improvement comes with a higher energy demand. Therefore, the significance of energy conservation and management in the commercial greenhouse has been emphasized to enable cost efficient crop production. This Doctoral Thesis presents an assessment of energy pathways for improved greenhouse performance by reducing the direct energy inputs and by conserving energy throughout the system. A reference theoretical model for analyzing the energy performance of a greenhouse has been developed using TRNSYS. This model is verified using real data from a conventional greenhouse in Stockholm (Ulriksdal). With this, a number of energy saving opportunities (e.g. double glazing) were assessed one by one with regards to the impact on the annual heating, cooling and electricity demand. Later, a multidimensional energy saving method, the “Closed Greenhouse”, was introduced. The closed greenhouse is an innovative concept with a combination of many energy saving opportunities. In the ideal closed greenhouse configuration, there are no ventilation windows, and the excess heat, in both sensible and latent forms, needs to be stored using a seasonal thermal energy storage. A short term (daily) storage can be used to eliminate the daily mismatch in the heating and cooling demand as well as handling the hourly fluctuations in the demand. The key conclusion form this work is that the innovative concept “closed greenhouse” can be cost-effective, independent of fossil fuel and technically feasible regardless of climate condition. For the Nordic climate case of Sweden, more than 800 GWh can be saved annually, by converting all conventional greenhouses into this concept. Climate change mitigation will follow, as a key impact towards sustainability. In more detail, the results show that the annual heating demand in an ideal closed greenhouse can be reduced to 60 kWhm-2 as compared to 300 kWhm-2 in the conventional greenhouse. However, by considering semi-closed or partly closed greenhouse concepts, practical implementation appears advantageous. The required external energy input for heating purpose can still be reduced by 25% to 75% depending on the fraction of closed area. The payback period time for the investment in a closed greenhouse varies between 5 and 8 years depending on the thermal energy storage design conditions. Thus, the closed greenhouse concept has the potential to be cost effective. Following these results, energy management pathways have been examined based on the proposed thermo-economic assessment. From this, it is clear that the main differences between the suggested scenarios are the type of energy source, as well as the cooling and dehumidification strategies judged feasible, and that these are very much dependent on the climatic conditions Finally, by proposing the “solar blind” concept as an active system, the surplus solar radiation can be absorbed by PVT panels and stored in thermal energy storage for supplying a portion of the greenhouse heating demand. In this concept, the annual external energy input for heating purpose in a commercial closed greenhouse with solar blind is reduced by 80%, down to 62 kWhm-2 (per unit of greenhouse area), as compared to a conventional configuration. Also the annual total useful heat gain and electricity generation, per unit of greenhouse area, by the solar blind in this concept is around 20 kWhm-2 and 80 kWhm-2, respectively. The generated electricity can be used for supplying the greenhouse power demand for artificial lighting and other devices. Typically, the electricity demand for a commercial greenhouse is about 170 kWhm-2. Here, the effect of “shading” on the crop yield is not considered, and would have to be carefully assessed in each case. / Hållbarhet har legat i fokus under decennier. En av de mest utmanande områdena är jordbrukssektorn, där. kommersiella växthus är ett av de mest effektiva odlingsalternativen med en avkastning per odlad yta upp till 10 gånger högre än för jordbruk på friland. Dock kommer denna förbättring med ett högre energibehov. Därför är energieffektivisering i kommersiella växthus viktig för att möjliggöra kostnadseffektiv odling. Denna doktorsavhandling presenterar en utvärdering av olika energiscenarios för förbättring av växthusens prestanda genom att minska extern energitillförsel och spara energi genom i systemet som helhet. För studien har en teoretisk modell för analys av energiprestanda i ett växthus utvecklats med hjälp av TRNSYS. Denna modell har verifierats med hjälp av verkliga data från ett konventionellt växthus i Stockholm (Ulriksdal). Med denna modell har ett antal energibesparingsåtgärder (som dubbelglas) bedömts med hänsyn till de totala värme-, kyl-och elbehoven. En flerdimensionell metod för energibesparing, det s.k. "slutna växthuset", introduceras. Det slutna växthuset är ett innovativt koncept som är en kombination av flera energibesparingsmöjligheter. I den ideala slutna växthuskonfigurationen finns det inga ventilationsfönster och värmeöverskott, både sensibel och latent, lagras i ett energilager för senare användning. Daglig lagring kan användas för att eliminera den dagliga obalansen i värme-och kylbehovet. Ett säsongslager introduceras för att möjliggöra användandet av sommarvärme för uppvärmning vintertid. Den viktigaste slutsatsen från detta arbete är att ett sådant innovativt koncept, det "slutna växthuset" kan vara kostnadseffektiv, oberoende av fossila bränslen och tekniskt genomförbart oavsett klimatförhållanden. För det svenska klimatet kan mer än 800 GWh sparas årligen, genom att konvertera alla vanliga växthus till detta koncept. Det årliga värmebehovet i ett idealiskt slutet växthus kan reduceras till 60 kWhm-2 jämfört med 300 kWhm-2 i ett konventionellt växthus. Energibesparingen kommer även att minska miljöpåverkan. Även ett delvis slutet växthus, där en del av ytan är slutet, eller där viss kontrollerad ventilation medges, minskar energibehovet samtidigt som praktiska fördelar har kunnat påvisas. Ett delvis slutet växthus kan minska energibehovet för uppvärmning med mellan 25% och 75% beroende på andelen sluten yta. En framräknad återbetalningstid för investeringen i ett slutet växthus varierar mellan 5 och 8 år beroende på design av energilagringssystemet. Sålunda har det slutna växthuskonceptet potential att vara kostnadseffektiv. Mot bakgrund av dessa lovande resultat har sedan scenarios för energy management analyserats med hänsyn till termo-ekonomiska faktorer. Från detta är det tydligt att de viktigaste skillnaderna mellan de föreslagna scenarierna är den typ av energikälla, samt kyl- och avfuktningsstrategier som används, och dessa val är mycket beroende av klimatförhållandena. Slutligen, föreslås ett nytt koncept, en s.k. "solpersienn", vilket är ett aktivt system där överskottet av solstrålningen absorberas av PVT-paneler och lagras i termiskenergilager för att tillföra en del av växthuseffekten värmebehov. I detta koncept minskar den årliga externa energitillförseln för uppvärmning i ett slutet växthus med 80%, ner till 62 kWhm-2. Den totala värme- och elproduktionen, med konceptet "solpersienn" blir cirka 20 kWhm-2 respektive 80 kWhm-2. Elproduktion kan användas för artificiell belysning och annan elektrisk utrustning i växthuset. / <p>QC 20130910</p>
12

Optimal Operation of Climate Control Systems of Indoor Ice Rinks

Jain, Rupali January 2012 (has links)
The electric power sector is undergoing significant changes with the development of Smart Grid technologies and is rapidly influencing the way we consume energy. Demand Response (DR) is an important element in the emerging smart grid paradigm and is paving way for the more sophisticated implementation of Energy Hub Management Systems (EHMSs). Utilities are looking at Demand Side Management (DSM) and DR services that allow customers to make informed decisions regarding their energy consumption which in return, can help the energy providers to reduce their peak demand and hence enhance grid sustainability. Ice rinks are large commercial buildings which facilitate various activities such as hockey, figure skating, curling, recreational skating, public arenas, auditoriums and coliseums. These have a complex energy system; in which an enormous sheet of ice is maintained at a low temperature while at the same time the spectator stands are heated to ensure comfortable conditions for the spectators. Since indoor ice rinks account for a significant share of the commercial sector and are in operation for more than 8 months a year, their contribution in the total demand cannot be ignored. There is significant scope for energy savings in indoor ice rinks through optimal operation of their climate control systems. In this work, a mathematical model of indoor ice rinks for the implementation of EHMS is developed. The model incorporates weather forecast, electricity price information and end-user preferences as inputs and the objective is to shift the operation of climate control devices to the low electricity price periods, satisfying their operational constraints while having minimum impact on spectator comfort. The inside temperature and humidity dynamics of the spectator area are modeled to reduce total electrical energy costs while capturing the effect of climate control systems including radiant heating system, ventilation system and dehumidification system. Two different pricing schemes, Real Time Pricing (RTP) and Time-of-Use (TOU), are used to assess the model, and the resulting energy costs savings are compared. The expected energy cost savings are evaluated for a 8 month period of operation of the rink incorporating the uncertainties in electricity price, weather conditions and spectator schedules through Monte Carlo simulations. The proposed work can be implemented as a supervisory control in existing climate controllers of indoor ice rinks and would play a significant role in the enforcement of EHMS in Smart Grids.
13

Optimal Operation of Climate Control Systems of Indoor Ice Rinks

Jain, Rupali January 2012 (has links)
The electric power sector is undergoing significant changes with the development of Smart Grid technologies and is rapidly influencing the way we consume energy. Demand Response (DR) is an important element in the emerging smart grid paradigm and is paving way for the more sophisticated implementation of Energy Hub Management Systems (EHMSs). Utilities are looking at Demand Side Management (DSM) and DR services that allow customers to make informed decisions regarding their energy consumption which in return, can help the energy providers to reduce their peak demand and hence enhance grid sustainability. Ice rinks are large commercial buildings which facilitate various activities such as hockey, figure skating, curling, recreational skating, public arenas, auditoriums and coliseums. These have a complex energy system; in which an enormous sheet of ice is maintained at a low temperature while at the same time the spectator stands are heated to ensure comfortable conditions for the spectators. Since indoor ice rinks account for a significant share of the commercial sector and are in operation for more than 8 months a year, their contribution in the total demand cannot be ignored. There is significant scope for energy savings in indoor ice rinks through optimal operation of their climate control systems. In this work, a mathematical model of indoor ice rinks for the implementation of EHMS is developed. The model incorporates weather forecast, electricity price information and end-user preferences as inputs and the objective is to shift the operation of climate control devices to the low electricity price periods, satisfying their operational constraints while having minimum impact on spectator comfort. The inside temperature and humidity dynamics of the spectator area are modeled to reduce total electrical energy costs while capturing the effect of climate control systems including radiant heating system, ventilation system and dehumidification system. Two different pricing schemes, Real Time Pricing (RTP) and Time-of-Use (TOU), are used to assess the model, and the resulting energy costs savings are compared. The expected energy cost savings are evaluated for a 8 month period of operation of the rink incorporating the uncertainties in electricity price, weather conditions and spectator schedules through Monte Carlo simulations. The proposed work can be implemented as a supervisory control in existing climate controllers of indoor ice rinks and would play a significant role in the enforcement of EHMS in Smart Grids.
14

Replacing Setpoint Control with Machine Learning : Model Predictive Control Using Artificial Neural Networks

Dahlberg, Emil, Mineur, Mattias, Shoravi, Linus, Swartling, Holger January 2020 (has links)
Indoor climate control is responsible for a substantial amount of the world's total energy expenditure. In a time of climate crisis where a reduction of energy consumption is crucial to avoid climate disaster, indoor climate control is a ripe target for eliminating energy waste. The conventional method of adjusting the indoor climate with the use of setpoint curves, based solely on outdoor temperature, may lead to notable inefficiencies. This project evaluates the possibility to replace this method of regulation with a system based on model predictive control (MPC) in one of Uppsala University Hospitals office buildings. A prototype of an MPC controller using Artificial Neural Networks (ANN) as its system model was developed. The system takes several data sources into account, including indoor and outdoor temperatures, radiator flowline and return temperatures, current solar radiation as well as forecast for both solar radiation and outdoor temperature. The system was not set in production but the controller's predicted values correspond well to the buildings current thermal behaviour and weather data. These theoretical results attest to the viability of using the method to regulate the indoor climate in buildings in place of setpoint curves. / Bibehållande av inomhusklimat står för en avsevärd del av världens totala energikonsumtion. Med dagens klimatförändringar där minskad energikonsumtion är viktigt för den hållbara utvecklingen så är inomhusklimat ett lämpligt mål för att förhindra slösad energi. Konventionell styrning av inomhusklimat använder sig av börvärdeskurvor, baserade enbart på utomhustemperatur, vilket kan leda till anmärkningsvärt energispill. Detta projekt utvärderar möjligheten att ersätta denna styrmetod med ett system baserat på model predictive control (MPC) och använda detta i en av Akademiska sjukhusets lokaler i Uppsala. En MPC styrenhet som använder Artificiella Neurala Nätverk (ANN) som sin modell utvecklades. Systemet använder sig av flera datakällor däribland inomhus- och utomhustemperatur, radiatorslingornas framlednings- och returtemperatur, rådande solinstrålning såväl som prognoser för solinstrålning och utomhustemperatur. Systemet sattes inte i produktion men dess prognos stämmer väl överens med tillgänglig väderdata och husets termiska beteende. De presenterade resultaten påvisar metoden vara ett lämpligt substitut för styrning med börvärdeskurvor.
15

Model Predictive Climate Control for Electric Vehicles

Norstedt, Erik, Bräne, Olof January 2021 (has links)
This thesis explores the possibility of using an optimal control scheme called Model Predictive Control (MPC), to control climatization systems for electric vehicles. Some components of electric vehicles, for example the batteries and power electronics, are sensitive to temperature and for this reason it is important that their temperature is well regulated. Furthermore, like all vehicles, the cab also needs to be heated and cooled. One of the weaknesses of electric vehicles is their range, for this reason it is important that the temperature control is energy efficient. Once the range of electric vehicles is increased the down sides compared to traditional combustion engine vehicles decrease, which could lead to an increase in the usage of electric vehicles. This could in turn lead to a decrease of greenhouse gas emission in the transportation sector. With the help of MPC it is possible for the controller to take more factors into consideration when controlling the system than just temperature and in this thesis the power consumption and noise are also taken into consideration. A simple model where parts of the climate system’s circuits were seen as point masses was developed, with nonlinear heat transfers occurring between them, which in turn were controlled by actuators such as fans, pumps and valves. The model was created using Simulink and MATLAB, and the MPC toolbox was used to develop nonlinear MPC controllers to control the climate system. A standard nonlinear MPC, a nonlinear MPC with custom cost functions and a PI controller where all developed and compared in simulations of a cooling scenario. The controllers were designed to control the temperatures of the battery, power electronics and the cab of an electric vehicle. The results of the thesis indicate that MPC could reduce power consumption for the climate control system, it was however not possible to draw any final conclusions as the PI controller that the MPC controllers were compared to was not well optimized for the system. The MPC controllers could benefit from further work, most importantly by applying a more sophisticated tuning method to the controller weights. What was certain was that it is possible to apply this type of centralized controller to very complex systems and achieve robustness without external logic. Even with the controller keeping track of six different temperatures and controlling 15 actuators, the control loop runs much faster than real time on a modern computer which shows promise with regard to implementing it on an embedded system.
16

Perturbed Optimal Control for Connected and Automated Vehicles

Gupta, Shobhit January 2022 (has links)
No description available.
17

Inneklimatet på Skoklosters slott : en studie av ett klimatexperiments första år

Justin Moll, Adam January 2014 (has links)
Inneklimatet på Skoklosters slott är på vissa håll problematiskt. Mögelangrepp förekommer i somliga rum, främst sådana som är belägna i norrläge och därmed lite kallare än övriga rum. För att finna en lösning på mögelproblemen inleddes våren 2013 ett treårigt experiment vars syfte var att utröna om mögelproblemen skulle kunna undvikas med aktiv klimatstyrning, vilket inte funnits innan experimentet. Tre olika klimatstyrningsanläggningar installerades i tre rum på slottet, samtidigt som mätningar gjordes i referensrum utan aktiva åtgärder. De tre klimatstyrningsanläggningarna som valdes ut var avfuktning, skyddsvärme och fuktstyrd ventilation. I mars 2014 avslutades första året av experimentet.Ur mögelrisksynpunkt har inneklimatet i nästan alla rum, både försöks- och referensrum, varit relativt godartat. Sämst inneklimat uppmättes i skyddsvärmerummet, vilket förmodligen beror på rummets egna förutsättningar snarare än skyddsvärmen. Bäst inneklimat hade rummet med den fuktstyrda ventilationen, som gav ett oväntat bra resultat och dessutom var den av klimatstyrningsanläggningarna som var mest i bruk. Det är emellertid för tidigt att med säkerhet säga vilken av anläggningarna som vore bäst för slottet.Vid en diskussion om de antikvariska konsekvenserna av en genomgripande installation av en klimatstyrninganläggning blev slutsatsen att det för slottets kulturhistoriska värde vore gynnsamt att göra en genomgripande installation ifall detta skulle innebära att slottets samlingar kunde behållas på plats. Rummens olika fysiska och kulturhistoriska förutsättningar kräver dock att individuella utformningar undersöks, vilket innebär att det kan bli aktuellt med en kombination av olika klimatstyrningsanläggningar. / The indoor climate of Skokloster palace is not without problems. There have been mould growth in some rooms, mainly those who are facing north and therefore are colder than other rooms. To find a solution for the problems with mould growth, a three-year long experiment was initiated in the spring of 2013. Its purpose was to examine if mould growth could be avoided with active climate control, which had not been tested previously in the palace. Three different climate control systems were installed in three rooms, and meanwhile the indoor climate of three rooms without active climate control was logged. The three climate control systems chosen were dehumidification, conservation heating, and humidity controlled ventilation. The first year of the experiment ended in March 2014.The climate in nearly all rooms was acceptable in a mould risk perspective. The room with conservation heating had the least suitable climate, which probably is explained by the condition of the room itself rather than the effects of the conservation heating. The room with humidity controlled ventilation hade the best climate during the year, and the ventilation system had the most uptime of the climate control systems. It is however too early to tell which system might be the best after only one year.When discussing what consequences a thorough installation of a climate control system might have on the cultural heritage values of Skokloster palace, the conclusion was that it would be favourable to install active climate control – if that allowed the collections of Skokloster to remain in the building. Due to the different physical and cultural conditions of the palace’s rooms, it will be necessary to find tailored solutions for climate control systems. In order to do that, a combination of different climate control systems might be worth looking into. / Spara och bevara - Energimyndighetens forskningsprogram för energieffektivisering i kulturhistoriskt värdefulla byggnader
18

Artificial Intelligence for Data Center Power Consumption Optimisation / Artificiell Intelligens för Energikonsumtionsoptimering i Datacenter

Lundin, Lowe January 2021 (has links)
The aim of the project was to implement a machine learning model to optimise the power consumption of Ericsson’s Kista data center. The approach taken was to use a Reinforcement Learning agent trained in a simulation environment based on data specific to the data center. In this manner, the machine learning model could find interactions between parameters, both general and site specific in ways that a sophisticated algorithm designed by a human never could. In this work it was found that a neural network can effectively mimic a real data center and that the Reinforcement Learning policy "TD3" could, within the simulated environment, consistently and convincingly outperform the control policy currently in use at Ericsson’s Kista data center.
19

Improving Climate Control and Energy Performance in Greenhouses and Livestock Houses: Modelling Advances and Experimental Results

Costantino, Andrea 16 December 2021 (has links)
[IT] Importanti cambiamenti sociodemografici, come la crescita della popolazione mondiale e l’urbanizzazione, stanno incrementando il fabbisogno di alimenti a livello mondiale. In contemporanea si sta assistendo ad una profonda trasformazione della dieta umana che tende sempre più a prediligere prodotti di origine animale, frutta e verdura al posto dei cereali. In quest’ottica, serre e stalle per l’allevamento intensivo possono ricoprire un ruolo di spicco, in quanto in grado di produrre tali alimenti con dei rendimenti decisamente maggiori rispetto a quelli che caratterizzano la produzione di vegetali in campo aperto e l’allevamento estensivo. Tra i vari fattori che contribuiscono ad incrementare la produttività di questi edifici agricoli vi è il controllo delle condizioni climatiche interne. Tale controllo del clima interno avviene, in molti casi, attraverso sistemi meccanici il cui utilizzo causa un considerevole consumo energetico che costituisce una minaccia per la transizione verso un’agricoltura più sostenibile. L’obiettivo generale di questa tesi è, quindi, di contribuire alla transizione verso un’agricoltura più sostenibile attraverso il miglioramento della prestazione energetica per il controllo climatico di serre e stalle per l’allevamento intensivo. Per raggiungere tale obiettivo, è stato adottato un triplice approccio basato su un’analisi di letteratura, campagne sperimentali di monitoraggio ed attività di modellazione energetica. L’analisi di letteratura è stata svolta con il fine di districare la complessa rete di relazioni esistente tra controllo climatico e altri domini di interesse della produzione agricola. Il nesso tra prestazione energetica e controllo climatico è stato approfondito analizzando dei set di dati reali acquisiti in una serra e due porcilaie attraverso campagne di monitoraggio. Questo nesso è stato ulteriormente approfondito adottando un approccio numerico che ha portato allo sviluppo e validazione di tre modelli di simulazione energetica per serre, per stalle da polli da carne e per stalle da suini da ingrasso. Ciascun modello di simulazione integra le principali caratteristiche tipiche di tali edifici per stimare con accuratezza i profili temporali delle condizioni ambientali interne e del consumo di energia termica ed elettrica. Le potenzialità di questi modelli nel migliorare la prestazione energetica e le condizioni climatiche di serre e stalle sono state esplorate analizzando specifiche problematiche relazionate al consumo energetico. Il modello energetico per le stalle per polli da carne, infatti, è stato adottato per valutare le potenzialità di un nuovo approccio per la progettazione energeticamente efficiente dell’involucro basato sull’energia primaria. Lo stesso modello è stato usato per valutare la variazione del consumo energetico causata dall’adozione di una strategia di ventilazione mirata al miglioramento del benessere dei polli allevati attraverso la riduzione della concentrazione interna di gas nocivi. Questa tesi contribuisce alla transizione verso una agricoltura più sostenibile fornendo nuove conoscenze e strumenti necessari al miglioramento della prestazione energetica per controllo climatico di serre e stalle per l’allevamento intensivo. Le analisi svolte, infatti, quantificano potenziali riduzioni del consumo energetico ottenibili attraverso l’implementazione di misure di efficientamento energetico, sia a livello di involucro (isolamento termico) che a livello di sistema di controllo climatico (ventilatori a portata variabile). Ulteriori misure per l’efficientamento energetico potrebbero essere valutate attraverso tali modelli che rappresentano importanti risultati di questa ricerca. Essi, infatti, potrebbero avere ricadute positive a livello locale in quanto vari portatori d’interesse (agricoltori, ingegneri e fabbricanti) potrebbero adottarli come strumenti di supporto alle decisioni per valutare nuove tecnologie, strategie e soluzioni mirate alla diminuzione del consumo energetico di serre e stalle. Questi nuovi modelli rappresentano anche un solido punto di partenza per future ricerche in questo campo. Futuri sviluppi potrebbero portare alla creazione di ulteriori moduli di calcolo per valutare altri aspetti, come la variazione della produttività, l’emissione di contaminanti e il benessere animale. Le nuove conoscenze generate in questa tesi potrebbero avere ricadute positive anche a livello globale, in quanto potrebbero rappresentare i fondamenti tecnici per nuovi quadri normativi e schemi di incentivi mirati al miglioramento della performance energetica di edifici agricoli controllati climaticamente attraverso una strategia di tipo top-down. / [ES] Importantes cambios sociodemográficos están conduciendo hacia un considerable crecimiento de la demanda de alimentos a nivel mundial. Al mismo tiempo se está observando una profunda transformación de la dieta humana, que tiende a incluir más productos de origen animal, fruta y verdura. Invernaderos y granjas de ganadería intensiva pueden desempeñar un papel principal, debido a que proporcionan los productos agrícolas necesarios con rendimientos notablemente mayores que los de la producción en campo abierto y de la ganadería extensiva. Entre los factores que contribuyen a incrementar la productividad de estos edificios agrícolas se sitúa el control de las condiciones climáticas internas. Dicho control se realiza a través de sistemas mecánicos cuyo uso causa un considerable consumo energético que representa una amenaza para la transición hacia una agricultura sostenible. El objetivo de esta tesis es contribuir a la transición hacia una agricultura más sostenible a través de la mejora de la prestación energética por control climático de invernaderos y granjas de ganadería intensiva. Para alcanzar dicho objetivo, se ha adoptado un enfoque triple basado en un análisis de literatura, campañas experimentales de monitorización y actividades de modelización energética. El análisis de literatura se ha llevado a cabo con el fin de desentrañar la red de relaciones existentes entre el control climático y otros dominios de interés de la producción agrícola. El nexo entre prestación energética y control climático se ha acometido analizando conjuntos de datos reales, adquiridos en un invernadero y dos granjas de cerdos. El análisis de dicho nexo se ha profundizado adoptando un enfoque numérico que ha llevado al desarrollo y validación de tres modelos de simulación energética para invernaderos y para granjas de pollos y cerdos. Las potencialidades de estos modelos para la mejora de las prestaciones energéticas y las condiciones climáticas se han explorado analizando problemáticas específicas. El modelo energético para granjas de pollos se ha adoptado para el diseño energéticamente eficiente de la envolvente de este tipo de edificio. El mismo modelo se ha usado para evaluar las variaciones de consumo energético causadas por la adopción de una estrategia de ventilación orientada a la mejora del bienestar de los pollos. Esta tesis contribuye a la transición hacia una agricultura más sostenible proporcionando nuevos conocimientos e instrumentos para la mejora de la prestación energética para el control climático de invernaderos y granjas. Los análisis realizados cuantifican potenciales disminuciones del consumo energético alcanzables a través de la implementación de medidas para la eficiencia energética a nivel de envolvente (aislamiento térmico) y a nivel de sistema de control climático (ventiladores con caudal variable). Ulteriores medidas para la eficiencia energética podrían evaluarse a través de dichos modelos que representan importantes resultados de esta investigación. Estos modelos podrían tener repercusiones positivas a nivel local, ya que muchas partes interesadas (agricultores, ingenieros y fabricantes) podrían adoptarlos como instrumentos de apoyo a la toma de decisiones para evaluar nuevas tecnologías y estrategias orientadas a la disminución del consumo energético. Estos nuevos modelos representan también un sólido punto de partida para futuras investigaciones en este campo. Futuros desarrollos podrían implementar nuevos módulos de cálculos para evaluar otros aspectos, como la variación de la productividad, la emisión de contaminantes y el bienestar animal. Los nuevos conocimientos generados en esta tesis podrían tener repercusiones positivas incluso a nivel global, puesto que podrían representar los fundamentos técnicos para nuevos marcos normativos y sistemas de incentivos orientados a la mejora de la prestación energética de edificios agrícolas controlados climáticamente a través de una estrategia de tipo top-down. / [CA] Importants canvis sociodemogràfics estan conduint cap a un considerable creixement de la demanda d'aliments a nivell mundial. Al mateix temps s'està observant una profunda transformació de la dieta humana, que tendeix a incloure més productes d'origen animal, fruita i verdura. Hivernacles i granges de ramaderia intensiva poden exercir un paper principal, pel fet que proporcionen els productes agrícoles necessaris amb rendiments notablement majors que els de la producció en camp obert i de la ramaderia extensiva. Entre els factors que contribueixen a incrementar la productivitat d'aquests edificis agrícoles se situa el control de les condicions climàtiques internes. Aquest control del clima intern es realitza a través de sistemes mecànics, l'ús dels quals causa un considerable consum energètic que representa una amenaça per a la transició cap a una agricultura sostenible. L'objectiu general d'aquesta tesi és contribuir a la transició cap a una agricultura més sostenible a través de la millora de la prestació energètica per al control climàtic d'hivernacles i granges de ramaderia intensiva. Per a aconseguir aquest objectiu, s'ha adoptat un enfocament triple basat en una anàlisi de literatura, campanyes experimentals de monitoratge i activitats de modelització energètica. L'anàlisi de literatura s'ha dut a terme amb la finalitat de desentranyar la complexa xarxa de relacions existents entre el control climàtic i altres dominis d'interés de la producció agrícola. El nexe entre prestació energètica i control climàtic s'ha analitzat amb conjunts de dades reals, adquirides en un hivernacle i dues granges de porcs. L'anàlisi d'aquest nexe s'ha aprofundit encara més adoptant un enfocament numèric que ha portat al desenvolupament i validació de tres models de simulació energètica per a hivernacles i per a granges de pollastres i porcs d'engreixament. Les potencialitats d'aquests models per a la millora de les prestacions energètiques i les condicions climàtiques s'han explorat analitzant problemàtiques específiques. El model energètic per a granges de pollastres s'ha adoptat per al disseny energèticament eficient de l'envolupant d'aquesta mena d'edifici. El mateix model s'ha usat per a avaluar les variacions de consum energètic causades per l'adopció d'una estratègia de ventilació orientada a la millora del benestar dels pollastres. Aquesta tesi contribueix a la transició cap a una agricultura més sostenible proporcionant nous coneixements i instruments per a la millora de la prestació energètica per al control climàtic d'hivernacles i granges. Les anàlisis realitzades quantifiquen potencials disminucions del consum energètic assolibles a través de la implementació de mesures per a l'eficiència energètica tant a nivell d'envolupant (aïllament tèrmic) com a nivell de sistema de control climàtic (ventiladors amb cabal variable). Ulteriors mesures per a l'eficiència energètica podrien avaluar-se a través d'aquests models que representen importants resultats d'aquesta investigació. Aquests models podrien tindre repercussions positives a nivell local, ja que moltes parts interessades (agricultors, enginyers i fabricants) podrien adoptar-los com a instruments de suport a la presa de decisions per a avaluar noves tecnologies i estratègies orientades a la disminució del consum energètic d'hivernacles i granges. Aquests nous models representen també un sòlid punt de partida per a futures investigacions en aquest camp. Futurs desenvolupaments podrien implementar nous mòduls de càlculs per a avaluar altres aspectes, com la variació de la productivitat, l'emissió de contaminants i el benestar animal. Els nous coneixements generats en aquesta tesi podrien tindre repercussions positives fins i tot a nivell global, ja que podrien representar els fonaments tècnics per a nous marcs normatius i sistemes d'incentius orientats a la millora de la prestació energètica d'edificis agrícoles controlats climàticament a través d'una estratègia de tipus top-down. / [EN] Socio-demographic trends, such as population growth and urbanization, are leading to a significant increase of the world food demand. At the same time, there is a shift of the human diet toward livestock products, vegetables, and fruit rather than cereals. Greenhouses and livestock houses can play a primary role since they can supply the necessary agricultural products with higher yields than on-field crop production and extensive animal farming. One way in which productivity is enhanced in these agricultural buildings is by a fine-tuned control of the indoor climate conditions. For this purpose, mechanical climate control systems are often adopted, but they entail a considerable energy consumption whose estimated increase may jeopardize the transition toward a sustainable agriculture. The overall objective of this thesis, hence, is to contribute to the transition toward a sustainable agriculture by improving the energy performance for climate control of greenhouses and livestock houses. To achieve this objective, a three-pronged approach was taken involving a literature review, experimental monitoring campaigns, and energy modelling activities. The literature review was performed to unpick the tangle of mutual relations between climate control and other domains of agricultural production. The nexus between energy performance and climate control was investigated analyzing real datasets acquired through monitoring campaigns performed in a greenhouse and two pig houses. This nexus was further studied adopting a numerical approach which led to the development and validation of three energy simulation models for greenhouses, broiler houses and pig houses. Each simulation model integrates the main features typical of greenhouses and livestock houses to estimate the time profiles of lumped indoor climate conditions and thermal and electrical energy consumption. The opportunities in improving the energy performance and the indoor climate conditions provided by the developed energy models were explored by analyzing specific energy-related problems. The broiler house energy model was adopted to evaluate the potentialities of a new primary energy approach for the energy-efficient envelope design of broiler houses. The same model was applied to evaluate the variation of energy consumption achieved by an improved ventilation strategy aimed at enhancing broiler welfare by reducing indoor noxious gas concentrations. This thesis contributes to the transition toward a more sustainable agriculture providing new knowledge and tools necessary for improving the energy performance for climate control of greenhouses and livestock houses. The performed analyses, in fact, quantify potential decrease of energy consumption achievable through the implementation of energy-efficient measures at both envelope -thermal insulation- and climate control system -variable angular speed fans- level. Further energy-efficient measures could be evaluated adopting the developed energy simulation models that are valuable outputs of this investigation. These models could have a positive impact at local level since stakeholders -farmers, engineers, and manufacturers- could adopt them as decision support tools for the evaluation of new technologies, strategies and solutions aimed at decreasing the overall energy consumption of greenhouses and livestock houses. These novel models represent also a robust starting point for future research in this field. Future advances may lead to the development of further calculation modules to evaluate other aspects of greenhouses and livestock houses, such as productivity variations, contaminant emissions and animal welfare. The new knowledge generated in this thesis could have positive impacts also at global level since it may represent the technical basis for new normative frameworks and incentive schemes aimed at improving the energy performance of climate-controlled agricultural buildings through a top-down approach. / Costantino, A. (2021). Improving Climate Control and Energy Performance in Greenhouses and Livestock Houses: Modelling Advances and Experimental Results [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/178457 / TESIS

Page generated in 0.139 seconds