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Jerome, David. "Building load analysis and graphical display as a design tool." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16410.
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Cleaveland, John P. "Loadcal : a microcomputer simulation for estimating heating and cooling loads for commercial buildings." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/23099.
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Rodriguez, German Darío Rivas. "Decentralized Architecture for Load Balancing in District Heating Systems." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3329.
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Context. In forthcoming years, sustainability will lead the development of society. Implementation of innovative systems to make the world more sustainable is becoming one of the key points for science. Load balancing strategies aim to reduce economic and ecological cost of the heat production in district heating systems. Development of a decentralized solution lies in the objective of making the load balancing more accessible and attractive for the companies in charge of providing district-heating services. Objectives. This master thesis aims to find a new alternative for implementing decentralized load balancing in district heating systems. Methods. The development of this master thesis involved the review of the state-of-the-art on demand side management in district heating systems and power networks. It also implied the design of the architecture, creation of a software prototype and execution of a simulation of the system to measure the performance in terms of response time. Results. Decentralized demand side management algorithm and communication framework, software architecture description and analysis of the prototype simulation performance. Conclusions. The main conclusion is that it is possible to create a decentralized algorithm that performs load balancing without compromising the individuals’ privacy. It is possible to say that the algorithm shows good levels of performance not only from the system aggregated response time, but also from the individual performance, in terms of memory consumption and CPU consumption.(+46) 709706206
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Sultan, Sahira. "Cost Evaluation of Building Space Heating; District Heating and Heat Pumps." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-37137.
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Climate change and energy efficiency has become a matter of concern in recent times; therefore, energy efficiency of buildings has drawn major attention. According to the European Commission, EU countries must improve energy efficiency of existing buildings by retrofitting and renovating the buildings. A case study of a renovated commercial building is considered in this degree project. A model of the building is developed in the IDA Indoor Climate and Energy (IDA ICE) software. The model is then augmented to include renovations in the building. Further, the model is simulated in IDA ICE before and after renovations to investigate the impact of renovations on energy consumption of the building for one year. The simulation results indicate peak demands of district heating that occur in the coldest days of the year. The peak demands of energy are expected to increase the district heating cost because they serve as a basis for new pricing model introduced by the energy providers. Hence, it is important from the customer point of view to reduce the peak loads for cost shavings. The project work also provides an insight into the alternative source of energy such as heat pumps to reduce the peak load demands of district heating.
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Urban, Graeme John. "Probabalistic load modelling of electrical demand of residential water heating." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20071.
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Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: Energy efficiency and the move to renewable energy resources are of vital importance in growing profitable and sustainable economies. In recent years, greater emphasis has been placed on institutions, companies and individuals to reduce their electrical energy demand through energy management. In an attempt to reduce the demand, the electrical power utility in South Africa, Eskom, has introduced Demand Side Management programs and substantial increases in electricity tariffs. In addition to these, tax incentives have been offered to help off-set the capital costs associated with the investments made in replacing old electrical equipment with new electrically efficient equipment. Thus the need for accurate Measurement and Verification of electrical energy demand reduction, to substantiate fiscal claims, has become imperative. The main purpose of Measurement and Verification is to investigate the actual monetary performance of an energy savings project. Energy savings assessments, based on purely deterministic baseline demand, do not adequately represent the statistical nature of the savings impacts of many practical load systems, as disclosed in a reporting period. This thesis presents the development of a generic probabilistic methodology to determine the demand profiles of preand post-Energy Conservation Measures (ECMs) for practical load systems. The difference between the simulated demand of the pre- and post-ECMs for a particular set of variables represent the electrical demand impact. The electrical demand of the pre- and post-ECMs is defined in terms of Probability Density Functions, and derived using a multivariate kernel density estimation algorithm. The approach is tested using a simulation model of a waterheating geyser implemented in MATLAB. Three different ECMs are simulated using the geyser model and demand density estimation. The results of the demand impacts of the ECMs are presented and evaluated. With regards to possible future research this methodology could be applied to the evaluation of the demand impacts of heat pump technologies and solar water heaters.
AFRIKAANSE OPSOMMING: en die skuif na hernubare energiebronne is van deurslaggewende belang vir die ontwikkeling van winsgewende en volhoubare ekonomieë. Onlangs is meer klem geplaas op instansies, maatskappye en individue om hul aanvraag na energie te verminder met behulp van energiebestuur. In ‘n poging om die aanvraag te verlaag, het Eskom, Suid-Afrika se elektrisiteitsverskaffer, aansienlike elektrisiteitstariefverhogings ingelyf en Aanvraagbestuursprogramme van stapel gestuur. Bykomend hiertoe is belastingaansporings ook aangebied, waarteen kapitale kostes, geassosieer met die vervanging van ou elektriese toerusting met nuwe elektries doeltreffende toerusting, afgeset kan word. Derhalwe het die behoefte aan akkurate Meting en Verifikasie van elektriese energie aanvraagvermindering, om finansiële eise te staaf, noodsaaklik geword. Die hoofdoel van Meting en Verifikasie is om die werklike finansiële prestasie van energiebesparingsprojek te ondersoek soos bekend gemaak word tydens ’n verslagdoeningstydperk. Energiebesparingassesserings wat slegs gebaseer word op die suiwer deterministiese basislyn aanvraag na elektrisiteit, verteenwoordig nie die werklike statistiese aard van die besparingsimpakte van baie praktiese lasstelsels nie. Hierdie tesis stel die ontwikkeling van generiese waarskynlikheids-metodologie voor, om die voor- en na- Energiebesparings-maatreëls se aanvraagprofiele vir sulke praktiese lasstelsels, vas te stel. Die verskil tussen die gesimuleerde aanvraag van die voor- en na- Energiebesparings-maatreëls vir spesifieke stel veranderlikes verteenwoordig die elektriese aanvraag impak. Die voor- en na- Energiebesparings-maatreëls van die energieverbruik profieldata word gedefinieer in terme van Waarskynlikheidsdigtheidsfunksies en afgelei deur gebruik te maak van meerveranderlike kerndigtheidafskattingsalgoritme. Die benadering is getoets deur gebruik te maak van simuleringsmodel van warmwaterstelsel geïmplimenteer in MATLAB. Drie verskillende voor- en na- Energiebesparings-maatreëls is gesimuleer met behulp van die warmwaterstelselmodel en aanvraag digtheidafskatting. Die resultate van die elektriese aanvraag impakte van die voor- en na- Energiebesparings-maatreëls word vervolgens bespreek en geëvalueer. Met betrekking tot moontlike toekomstige navorsing kan hierdie metodologie toegepas word om die aanvraag impakte van hittepomp- en sonwaterverwarmingstegnologieë te evalueer.
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Tabarra, M. "Load factor effects on thermally stratified solar storage tanks." Thesis, De Montfort University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356458.
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Fernandez, del Castillo Lisa. "Design of a novel test bench for induction heating load characterization." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90135.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.26
"June 2014." Cataloged from PDF version of thesis.
Includes bibliographical references (pages 87-89).
Magnetic materials used in induction heating applications have nonlinear magnetic properties with respect to field strength and frequency, which can be effectively characterized using experimental techniques. To this end, we present a test bench inverter optimized for induction heating experimentation, capable of driving an inductive load across a 1-100 kHz frequency range with up to 2 kW power. Harmonic distortion of the inverter is minimized with a novel multilevel topology and modulation scheme, thus allowing near-sinusoidal excitations to be obtained at varying field strengths and frequencies. To demonstration the capabilities of the test bench, we characterize the power dissipation of a loaded induction heating coil across a range of frequencies and power levels.
by Lisa Fernandez del Castillo.
S.M.
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Provatas, Spyridon. "An Online Machine Learning Algorithm for Heat Load Forecasting in District Heating Systems." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3475.
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Context. Heat load forecasting is an important part of district heating optimization. In particular, energy companies aim at minimizing peak boiler usage, optimizing combined heat and power generation and planning base production. To achieve resource efficiency, the energy companies need to estimate how much energy is required to satisfy the market demand. Objectives. We suggest an online machine learning algorithm for heat load forecasting. Online algorithms are increasingly used due to their computational efficiency and their ability to handle changes of the predictive target variable over time. We extend the implementation of online bagging to make it compatible to regression problems and we use the Fast Incremental Model Trees with Drift Detection (FIMT-DD) as the base model. Finally, we implement and incorporate to the algorithm a mechanism that handles missing values, measurement errors and outliers. Methods. To conduct our experiments, we use two machine learning software applications, namely Waikato Environment for Knowledge Analysis (WEKA) and Massive Online Analysis (MOA). The predictive ability of the suggested algorithm is evaluated on operational data from a part of the Karlshamn District Heating network. We investigate two approaches for aggregating the data from the nodes of the network. The algorithm is evaluated on 100 runs using the repeated measures experimental design. A paired T-test is run to test the hypothesis that the the choice of approach does not have a significant effect on the predictive error of the algorithm. Results. The presented algorithm forecasts the heat load with a mean absolute percentage error of 4.77\%. This means that there is a sufficiently accurate estimation of the actual values of the heat load, which can enable heat suppliers to plan and manage more effectively the heat production. Conclusions. Experimental results show that the presented algorithm can be a viable alternative to state-of-the-art algorithms that are used for heat load forecasting. In addition to its predictive ability, it is memory-efficient and can process data in real time. Robust heat load forecasting is an important part of increased system efficiency within district heating, and the presented algorithm provides a concrete foundation for operational usage of online machine learning algorithms within the domain.
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Amrhein, Andrew Aloysius. "Induction Heating of Aluminum Cookware." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/77400.
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Induction heating has become a popular alternative to other heat sources for stovetop cooking applications due to performance, efficiency, control response, and safety. The main drawback is that extreme difficulty is encountered when trying to head low-resistivity, non-ferromagnetic metals such as aluminum and copper, which are commonly used for cookware in several societies. The lack of ferromagnetic properties, resulting in no hysteresis dissipation, and low resistivity of such metals results in an impractically low resistance reflected through the work coil. The resultant impedance complicates inverter design, as it is too low to be efficiently driven with conventional inverter topologies. The magnitudes of current involved in exciting this impedance also severely impact the efficiency of the coil and resonant components, requiring extreme care in coil design. This work explores various techniques that have been proposed and/or applied to efficiently heat low-resistivity cookware and the associated limitations. A transformer-coupled series-load-resonant topology driven by a full-bridge inverter is proposed as a means of efficiently heating aluminum cookware within practical design constraints. The experimental circuit is built and successfully tested at an output power of 1.66kW. The procedure of optimizing the work coil for improved efficiency is also presented along with the procedure of measuring coil efficiency. An improved circuit incorporating switch voltage detection to guarantee zero-voltage switching is then built in order to overcome limitations of this design.Master of Science
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Landis, Mark J. "Development of a Parametric Data-Driven Fixed Shading Device Design Workflow." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553250987067742.
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Yadur, Balagangadhar Nakul. "Field Load Data Acquisition with regard to Vibration, Shock and Climate including Self-heating of ECUs." Master's thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-161558.
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For the reliability design of Engine Control Unit devices in motor vehicles, the knowledge of stresses occurring in the field within the product service life is
essential.
In addition to the environmental influences such as temperature, moisture and humidity, vibration and shock issues are in focus. To ensure the robustness of the products and they are still easily and inexpensively made, they must be interpreted appropriately in the development process. For this, the load spectra for the mechanical influences of road conditions and operating conditions are to be determined. Work will also include temperature and humidity values examined on typical installation locations. The essential everyday situations (commuters, taxi, farmer, ...) should be considered.
Existing measurement technology must be combined to this end a comprehensive logger system with communication to the vehicle.
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Poutiainen, Zacharias. "Short-Term Heat Load Forecasting in District Heating Systems : A Comparative Study of Various Forecasting Methods." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265670.
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Short term heat load forecasts are vital for optimal production planning and commitment of generation units. The generation utility also bares a balance responsibility toward the electricity market as a result of CHP generation. Sub-optimal load forecasts can lead to high costs relating to unit commitment, fuel usage and balancing costs. This thesis presents the empirical comparison of various models for 24h heat load forecasting. Five methods were investigated including four supervised machine learning algorithms; neural networks, support vector machines, random forests and boosted decision trees and one auto-regressive time series model; ARIMAX. The models were developed, and evaluated using cross validation with one year of hourly heat load data from a local district heating system and corresponding meteorological data from the same time period. The thesis also investigates the impact of feature selection on the predictive power and generalization ability of the models. The results indicate a significant difference in forecast accuracy between the methods with neural networks and ARIMAX showing the best and similar performance followed by the support vector machine, boosted decision trees and random forest.Korttidsprognoser för fjärrvärmelast är mycket viktiga för optimal produktionsplanering. Energibolag som använder kraftvärme bär dessutom balansansvar gentemot elmarknaden. Sub-optimala lastprognoser kan leda till höga kostnader för start och stopp, bränsleåtgång och obalanser. Detta examensarbete presenterar den empiriska jämförelsen av olika modeller avseende 24-timmars lastprognostisering. Totalt fem metoder undersöktes varav fyra maskininlärningsalgoritmer; neurala nätverk, stödvektormaskin, random forest samt boosted desicion trees och en tidsseriemodell; ARIMAX. Modellerna utvecklades, och utvärderades med hjälp av korsvalidering på ett års värden av timvis lastdata från ett lokalt fjärrvärmenät och motsvarande väderdata för samma tidsperiod. Examensarbetet undersöker även inverkan av variabelselektion på prognosernas precision och förmåga att generalisera. Resultaten tyder på en signifikant skillnad i noggrannhet mellan de olika modellerna. Bäst resultat uppnåddes av neurala nätverk och ARIMAX med en liten skillnad sinsemellan, följt av stödvektormaskin, boosted decision trees och random forest.
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Somasundaram, Meena Sivalingam. "Pulsed power and load-pull measurements for microwave transistors." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003293.
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Eriksson, Andreas. "Metoder för lastprioritering i fjärrvärmecentraler." Thesis, Uppsala universitet, Fasta tillståndets fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-139466.
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A problem in the field of district heating is the oil burners needed to provide power when a peak load occurs. One possible way of reducing the needed amount of oil is to reduce the power demand for space heating in the district-heating substations when the need for district heating water exceeds a certain limit. This can be done by use of a locally working controller function. In this Thesis the options concerning load priority are evaluated. To evaluate the potential for using controller functions concerning peak load priority an experiment was brought out in a chosen district-heating substation. The impact on the indoor thermal comfort during a heat reduction was also taken into account. With simulations and mathematical models the building and the indoor air cool down was evaluated. Also a survey was given to the residents to validate how the indoor thermal climate was affected during the experiment. Possible savings by using these kinds of functions were also accounted for. The result demonstrates that a simple controller function provides a possible way of reducing the power demand, but is not sufficiently reliable. This is mainly due to the used regulating parameter. With modifications or by adding additional regulating parameters such as water flow into the controller, the functionality can be improved. The result from the survey shows that during the experimental period the residents experienced a minor impact on the thermal comfort. Parameters, such as ventilation and heat losses also have a major impact on the building´s thermal inertia, especially at the lowest occurring outdoor temperatures. The simulations confirm the theory regarding the building heat capacity to prevent a negative impact on indoor thermal comfort. In addition, the indoor air temperature can initially decrease faster than the building framework, especially under the influence of ventilation. This must be taken into account when applying functions for load priority. Calculations indicate that the economical benefits by adapting functions for load priority are primarily for the heat-producer, due to reduced oil dependence and also other system aspects. The current ownership structure in Uppsala provides for a possible obstacle when it comes to expanded use of load priority functions. More incentives for the consumer are needed to provide for an increased usage of load priority functions in their district-heating substations.
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Barrett, Emily Lord. "The Investigation and Optimization of a Two-Heat-Pump System Incorporating Thermal Storage for Shaping Residential Heating Load." PDXScholar, 2016. http://pdxscholar.library.pdx.edu/open_access_etds/3025.
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Portland General Electric has proposed coupling one or more water tanks with two heat pumps in order to perform load-shifting in residential customer heating and cooling applications. By using the water tanks as a thermal storage unit, this project attempts to partially decouple energy consumption from generation to provide peak demand reduction and to better facilitate the integration of variable renewable energy resources. A scoping study was performed to evaluate the potential impact of this project if implemented in single family homes in Portland, Oregon. This study revealed that the system could provide meaningful savings in the cost of electricity to both the customer and utility. Additionally, an optimization algorithm was developed to dictate system operation and to maximize gains to the utility. Evolutionary algorithms were explored in an attempt to increase the effectiveness of the algorithm's search in limited computation time. Ultimately, an evolution strategy was selected as the most suitable based on tests run in winter and spring months. A genetic algorithm was then developed to handle fixed-speed heat pump operation for compatibility with an alpha-system prototype that has been developed by the research team.
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Dengiz, Thomas [Verfasser], and W. [Akademischer Betreuer] Fichtner. "Optimization approaches for exploiting the load flexibility of electric heating devices in smart grids / Thomas Dengiz ; Betreuer: W. Fichtner." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1232324027/34.
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Buddee, Ingrid. "Utveckling av lastmodell för Uppsala fjärrvärmenät." Thesis, Uppsala universitet, Avdelningen för systemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-229937.
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The aim of this study was to develop a load prognosis model for Uppsala district heating system to be used as a tool for heat production optimization. The methodwas to build three models for the different customer types; housing, industry andoffices and then scale them for the total system using data from Uppsala districtheating system. The heat load consists of two parts, one that is temperaturedependent and one that is dependent of the social behavior of the customers. Thetemperature part was modelled with an ARX model using an outdoor temperatureprognosis as input signal. The social behavior part was modelled using the mean ofthe social behavior from some days before and additionally by distinguishing betweenweekdays and weekends. The outcome was a model that would produce a prognosisfor the heat load for each customer type. The total model for the whole districtheating system was less accurate, but still usable. All models developed are howeverrelying on the quality of the available weather prognosis. The benefit of a precise loadprognosis is to facilitate production planning and optimization. Accurate predictions ofthe heat demand, especially in the case of peak load, will result in better productionplanning and thus cost efficiency.
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Su, Chang. "Electricity Projection with Peak Load Shifting Strategy in Wuxi Sino-Swedish Eco-City." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133920.
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Wuxi Sino-Swedish Eco-City, a pilot city region with an area of 2.4 km2, is a demonstration project for innovation in energy technology and integrated smart city solutions in China. After the 1st phase of the project, general outlines of the city’s energy system were drawn and applicable technologies are provided. However, no work has been performed on building electricity load projection and load analysis. This thesis will therefore firstly focus on establishing the building electricity load projection model, using simulation software STELLA. Then the model is scaled up for the whole city region. The simulation results show that there is foreseen to be electricity peak in summer and winter, due to the cooling and heating demand. Based on simulation results, an electricity DSM (demand side management) strategy should be implemented in order to balance the load. Peak load shifting strategy is thus chosen to be investigated. Two technology options (ice-storage system and thermal storage system), which could be implemented to balance the electricity peak, is analyzed by scenarios. Also, commercial feasibility of implementing such technologies is discussed.Wuxi Taihu Sino-Swedish Eco-City
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Bergentz, Tobias. "Identifying symptoms of fault in District Heating Substations : An investigation in how a predictive heat load software can help with fault detection." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-174442.
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District heating delivers more than 70% of the energy used for heating and domestichot water in Swedish buildings. To stay competitive, district heating needs toreduce its losses and increase capabilities to utilise low grade heat. Finding faultysubstations is one way to allow reductions in supply temperatures in district heatingnetworks, which in turn can help reduce the losses. In this work three suggestedsymptoms of faults: abnormal quantization, drifting and anomalous values, are investigatedwith the help of hourly meter data of: heat load, volume flow, supplyand return temperatures from district heating substations. To identify abnormalquantization, a method is proposed based on Shannon’s entropy, where lower entropysuggests higher risk of abnormal quantization. The majority of the substationsidentified as having abnormal quantization with the proposed method has a meterresolution lower than the majority of the substations in the investigated districtheating network. This lower resolution is likely responsible for identifying thesesubstation, suggesting the method is limited by the meter resolution of the availabledata. To improve result from the method higher resolution and sampling frequencyis likely needed.For identifying drift and anomalous values two methods are proposed, one for eachsymptom. Both methods utilize a software for predicting hourly heat load, volumeflow, supply and return temperatures in individual district heating substations.The method suggested for identifying drift uses the mean value of each predictedand measured quantity during the investigated period. The mean of the prediction iscompared to the mean of the measured values and a large difference would suggestrisk of drift. However this method has not been evaluated due to difficulties infinding a suitable validation method.The proposed method for detecting anomalous values is based on finding anomalousresiduals when comparing the prediction from the prediction software to themeasured values. To find the anomalous residuals the method uses an anomalydetection algorithm called IsolationForest. The method produces rankable lists inwhich substations with risk of anomalies are ranked higher in the lists. Four differentlists where evaluated by an experts. For the two best preforming lists approximatelyhalf of the top 15 substations where classified to contain anomalies by the expertgroup. The proposed method for detecting anomalous values shows promising resultespecially considering how easily the method could be added to a district heatingnetwork. Future work will focus on reducing the number of false positives. Suggestionsfor lowering the false positive rate include, alternations or checks on theprediction models used.
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Ji, Yiyi [Verfasser]. "Radiofrequency induced heating for controlled release of a load from thermoresponsive carriers: a 7.0 Tesla Thermal Magnetic Resonance Study / Yiyi Ji." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2020. http://d-nb.info/121807650X/34.
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Jönsson, Linnea. "Thermal energy storage systems in an energy company's district heating system : Exploring ways of handling daily and seasonal heat load variations in Höganäs." Thesis, Högskolan i Halmstad, Energivetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-29800.
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Taner, Ozun. "An Investigation Into The Age-based Thermal Energy Balance Of Occupied Classrooms In Primary Schools." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610280/index.pdf.
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The effect of indoor heat gain from occupants as a bio-thermal source was hypothetically
assessed in terms of its contribution to overall heating requirements during such occupancy
and hence to potential energy savings. The spaces considered were classrooms in a
sample of 6 public co-educational primary schools located within the city limits of
Ankara built after 1998, the date when compulsory primary education was integrated to
encompass grades 1 through 8 for ages 6 to 14, respectively. Being so, this allowed distinguishing
disparities among age groups on the basis of classroom density and body
surface area. Data for both were obtained from existing sources. As norms for the latter
essentially pertained to adult populations, pertinent corrections were made for each of the
age groups in question as well as for gender. Additional adjustments were made on the
basis of the literature in order to integrate data on local weather conditions into heat
balance equations. Energy requirements for heating were calculated according current
Turkish standards.
Results based on extensive comparisons using Student’
s t-test confirmed that there were significant differences between grades in terms of supplementary heating requirements. These differences were not, however, large enough to warrant any meaningful intervention with regard to such design aspects as window orientation, exterior wall composition and/or indoor temperature level.
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Eriksson, Stina. "Optimering av framledningstemperaturen i ett fjärrvärmenät genom lastmodellering och simulering." Thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32790.
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I Sverige är fjärrvärme den vanligaste uppvärmningsformen. Vatten värms upp i en fjärrvärmeanläggning och distribueras genom nedgrävda rör i marken, också kallat fjärrvärmenätet. En tillförlitlig energimodell anses vara ett bra och viktigt hjälpmedel för analyser av värmeförluster som uppstår i ett fjärrvärmenät vid distribueringen av det heta vattnet. Sandviken Energis styrning av framledningstemperaturen sker idag utifrån en inställd styrkurva som tar hänsyn till vad det är för utetemperatur. Det var av intresse för studien att jämföra denna styrning med en simulerad framledningstemperatur och identifiera övertemperaturer i Sandviken Energis fjärrvärmenät i Sandviken. Detta gjordes utifrån att undersöka hur olika faktorer påverkade värmebehovet. De påverkande faktorer som studerats i detta examensarbete var följande: utetemperatur, månad, tid på dygnet och vindhastighet. Mätdata gällande valda påverkande faktorer hämtades för perioderna 2015 till och med 2019, analyserades och indelades för att se deras påverkan på värmelasten. Utifrån indelningen av faktorerna utvanns ekvationer från deras effektkurvors trendlinjer. Ekvationerna användes för att skapa en simuleringsmatris för styrningen. En egenskapad masterekvation simulerade den ideala styrningen utifrån simuleringsmatrisen och de krav på påverkande faktorer som ställs av ett exempel-år. Den ideala styrningen beräknades om till en ideal framledningstemperatur och jämfördes därefter med den verkliga framledningstemperaturen. Tillsammans med en värmeförlustsimulering i NetSim, som resulterade i vad sparad energi per grad är värd, kunde besparingspotentialen beräknas. Resultatet visar på att en besparingspotential på 261 MWh är möjlig att uppnå vid en sänkning av framledningstemperaturen för att utesluta övertemperaturer i fjärrvärmenätet, vilket är en minskning med ca 1,8 % jämfört med det verkliga året. Detta skulle motsvara en besparing på ca 70 000 SEK genom en förändring av styrningen. En minskad framledningstemperatur kommer påverka resten av systemet positivt, bland annat för att returtemperaturen kommer minska, rökgaskondenseringens och pannornas effektivitet öka samt minskade utsläpp i form av bland annat CO2, för att nämna några exempel.In Sweden district heating is the most common form of heating. Water is heated in a district heating plant and distributed through buried pipelines in the ground, also called the district heating network. A reliable energy model is considered to be a good and important tool for analysis of heat losses that occur in a district heating network when the hot water is distributed. Sandviken Energi’s control of the supply temperature is based today on a set control curve that takes into account what the outdoor temperature is. It was of interest to this study to compare this control with a simulated supply temperature and identify overtemperatures in Sandviken Energi’s district heating network in Sandviken. This was done on the basis of examining how different factors affected the heat demand. The influencing factors studied in the thesis were the following: outdoor temperature, month, time of day and wind speed. Measurement data on selected influencing factors were collected for the periods 2015 through 2019, analyzed and subdivided to see their effect on the heat load. From the subdivision of the factors, equations were extracted from the trend lines of their effect curves. The equations were used to create a simulations matrix for the control. A custom master equation simulated the ideal control based on the simulation matrix and the demands on influencing factors set by an example year. The ideal control was recalculated to an ideal supply temperature and then compared with the actual supply temperature. Together with a heat loss simulation in NetSim, which resulted in what energy saved per degree is worth, the savings potential could be calculated. The result shows that a saving potential of 261 MWh is possible to achieve by lowering the supply temperature to exclude excess temperatures in the district heating network, which is a decrease of about 1.8 % compared to the real year. This would correspond to a savings of about 70 000 SEK through a change in control. A reduced supply temperature will have a positive impact on the rest of the system, including reducing the return temperature, increasing the efficiency of flue gas condensation and boilers, and reducing emissions such as CO2, to name a few examples.
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Yaser, Hussnain A. "Novel System Design For Residential Heating And Cooling Load Shift Using PCM Filled Plate Heat Exchanger And Auxiliaries For Economic Benefit And Demand Side Management." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397234246.
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Saker, Nathalie. "Contribution au pilotage de la charge pour accroître la flexibilité du système électrique." Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00812674.
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Les défis environnementaux et l'augmentation de la population viennent en preuve de l'importance de réfléchir à d'autres moyens de production tout en maintenant la sécurité et la fiabilité du système électrique. La sûreté du système électrique exige à tout moment que la production soit égale à la demande des consommateurs, pour ça, différentes solutions sont déjà mises en place, ces solutions consistent à mettre en marche des moyens de pointes couteux et polluants pendant les périodes de pointes, mais comme les moyens de production son insuffisants et vue la difficulté d'exploitation de nouveaux moyens de production, une nouvelle réflexion sur la gestion de la demande est apparue; celle-ci se base sur la possibilité à gérer la demande du consommateur final au lieu de la satisfaire.L'objectif de la thèse est d'étudier la possibilité à rendre des services au système électrique en appliquant des actions de contrôle dites de DR (Demand Response), sur différents types de charges électriques. Ces actions de DR représentent des interruptions partielles appliquées sur les charges électriques de type thermique. Notre choix s'est basé sur ces types de charges parce que celles-ci emmagasinent de la chaleur respectivement dans l'air et dans l'eau; qui peut être restituée pendant la période de contrôle ou d'interruption. Néanmoins, il existe un effet négatif qui suit le contrôle de ces charges car l'énergie effacée de ces charges est reportée à l'instant de reconnexion de celles-ci; ce report prend la forme d'un pic de consommation nommé CLPU (Cold Load Pick-Up) et qui apparait au moment de la reconnexion. Le CLPU représente un problème qui doit être géré, et sa magnitude dépend des types d'actions de contrôle qu'on veut implanter et aussi des conditions du système électrique (contingence, défaillance d'une unité de production ou besoin de réserve de puissance). Pendant la thèse, le CLPU est contrôlé et optimisé ainsi que la puissance effacée. Un cas d'étude est présenté sur la contribution des actions de gestion de la demande à l'ajustement entre la demande et la production et l'effet généré sur le réglage secondaire de fréquence.
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Bengtsson, Conny. "Ersättning av fossilt bränsle i värmeproduktion: Pulverbrännare till befintliga oljepannor." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-23452.
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Vi står inför en förändring, att minska vårt beroende av fossil energi till förmån för en ökad användning av förnybar energi. Incitament i form av ökade punktskatter på fossilt bränsle påskyndar omställningen för företag till förnybar energi och- eller energieffektivisering av sin produktion. Konsekvensen blir en successivt fördyrad kostnad för produktion av fjärrvärme med eldningsolja till tillverkningsindustrin. Punktskatt på eldningsolja stiger med 41 procent, från 2010 till 2015 för företagen. Att konvertera befintliga oljepannor med träpulverbrännare är en lösning för att hålla produktionskostnaden nere och behålla sin konkurrenskraft. I detta examensarbete utreds möjligheten att konvertera oljepannor i storleksklassen 5-10 MW. Studien tar ett helhetsgrepp om RMT´s fjärrvärmeproduktion för att söka svaret på, om det är möjligt att göra en konvertering ur ett tekniskt, hållbarhets och ekonomiskt perspektiv. Det kända behovet av spetslast från oljepannorna vid -3°C visade sig inte stämma utan brytpunkten hamnade vid -6°C. Resultatet pekar på att en 10 MW oljepanna kan konverteras till 5 MW träpulver men ändå behålla sin ursprungliga effekt genom en kombibrännare. Tidigare problem som fanns med träpulveranläggningar är åtgärdade och referensanläggningar i den aktuella storleksklassen finns i drift. Ett förfrågningsunderlag skickades ut för att få in budgetpris på konvertering av 5 och 10 MW oljepannor för utvärdering. Trots att alla leverantörer gavs samma förutsättningar så varierade budgetpriserna väldigt mycket. En stor överraskning var den korta payoff tid på konverteringar med liten värmeeffekt. Att en konvertering av en 10 MW OP har en återbetalningstid på 20 månader var rätt osannolikt innan studien utfördes. Denna studie kan även ses som en inspirationskälla till andra företag som har mindre spetslastpannor och vill fasa ut sitt fossila beroende med förnybar energi, samtidigt behålla sin konkurrenskraft. I fjärrvärmebranschen är dessa 5 och 10 MW oljepannor vanliga som spetslastpannor. Det finns ca 1000 oljepannor i storleken 5-10 MW i Sverige så det bör finnas en stor potential i att konvertera oljepannor till träpulver.We are facing a change, to reduce our dependency on fossil fuels in favor of increased use of renewable energy. Incentives in the form of increased excise taxes on fossil fuels for companies accelerate the conversion to renewable energy or energy efficiency of its production. The consequence is a progressively more expensive cost for district heating with fuel oil to manufacturing industry. Excise tax on fuel oil rises by 41 percent, from 2010 to 2015 for those companies. To convert existing oil boilers with woodpowderburner is a solution to keep production costs down and remain competitive. In this thesis studied the possibility of converting oil boilers in the size range of 5 to 10 MW. The study takes a holistic approach to RMT's district heating to search the answer, if it is possible to do a conversion from a technical, sustainability and economic perspective. The felt need for peak load from oil boilers at -3° C appeared not to sue; it ended up at -6° C. The results indicate that a 10 MW oil boiler can be converted to 5 MW wood powder and while retaining its original power through a combination burner. Previously problems with woodpowderplant are taken care of and reference facilities in the current magnitude are in operation. An inquiry was sent out to get budget prices at a conversion of 5 and 10 MW oil boilers for evaluation. Even though all the suppliers was given the same opportunities so varied budget prices very much. A big surprise was the short payoff time on conversions of small oil boilers. The conversion of a 10 MW OP has a payback period of 20 months and that was rather unlikely before the study was performed. This study can also be seen as a source of inspiration to other companies that have small peak load boilers and want to phase out their fossil fuel dependence with renewable energy, and retain their competitiveness. In the district heating sector, these 5 and 10 MW oil boilers are ordinary peak load boilers. There are about 1000 oil boilers in the size from 5 to 10 MW in Sweden so it should be a large potential in converting oil boilers to wood powder
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Elofsson, Fredrik. "Optimering av last och produktion i Gävles fjärrvärmenät : Reducering av effekttoppar via värmelagring i byggnader." Thesis, Högskolan i Gävle, Energisystem och byggnadsteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-29732.
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District heating is today the most common way of providing a building with heat and hot water in Sweden. It is an environmentally friendly product mostly used with renewable fuel. However, at power peaks most companies use production units that are more expensive and worse for the environment and should therefore be avoided as much as possible. This can be done with a method called load management. When a power peak occurs, the heat supply to buildings connected to the district heating system can be temporarily reduced. The heat energy can later be returned when the heat demand is lower. Thanks to the heat inertia of the buildings, the indoor temperature will not fall within the time frame for the load management. Historical data has been analysed to identify when and why power peaks occur in the district heating network. Power peaks throughout the district heating network have proved difficult to identify. However, for individual consumers clear patterns of power peaks have emerged. These power peaks mainly occur because of large use of hot water but also because of the shifting outdoor temperature. In order to see how the production cost would differ from the actual outcome load management was applied for Gävle's district heating 2018. The load management was calculated manually by identifying the most expensive production unit on an hourly basis. If a cheaper production unit had the potential to deliver higher power the next hour, the production was moved to the cheaper production unit. The process was repeated for each hour during 2018. After carrying out load management for Gävle's district heating network, 1 457 MWh had been shifted to a cheaper production unit. This resulted in a financial saving of 1,0 % of the total production cost. The environmental savings showed a reduction from 6.1 to 5.9 g CO2eq /kWh a total of 197 tonne CO2eq. In the exact same way, a load management was performed for a scenario where Gävle and Sandviken's district heating network were connected. The gain for a load management with Sandviken will be considerably larger, a reduced production cost of 3.6 % is possible. The environmental savings showed a reduction from 8.4 to 7.8 CO2eq /kWh a total of 575 tonne CO2eq. For future efficient load management, buildings should be divided into different classes depending on the building's time constant. User patterns for the entire district heating network have proved difficult to detect. Artificial intelligence can be an option for short-term forecasting of the power outputFjärrvärme är idag det vanligaste sättet att förse en bostad med värme och tappvarmvatten i Sverige. Fjärrvärmen är ofta en miljövänlig produkt som kan produceras av till exempel biobränsle- och avfallseldade kraftvärmeverk eller spillvärme från industrier. Vid tillfälligt högt effektbehov, effekttoppar, använder sig merparten av bolagen av dyrare produktionsenheter med större miljöpåverkan. Dyrare produktionsenheter bör undvikas i största möjliga mån och i detta syfte används metoden laststyrning. Vid en effekttopp kan värmetillförseln till byggnader sänkas temporärt för att återföras några timmar senare när effektbehovet är lägre. Tack vare värmetrögheten i byggnaderna bör inomhustemperaturen inte sjunka inom tidsramen för laststyrning. Statistik från Gävles fjärrvärmanvändning på timbasis under 2018 har analyserats för att identifiera när och varför effekttoppar sker. Effekttoppar i hela fjärrvärmenätet har visat sig svåra att identifiera. På lokal nivå har däremot tydliga mönster för effekttoppar framkommit. Dessa effekttoppar beror till största del av tappvarmvattenanvändning men även förändringar i utomhustemperaturen. För att se hur produktion och last kunde skiljt sig från det verkliga utfallet tillämpades laststyrning för Gävles fjärrvärmeproduktion 2018. Laststyrningen beräknades manuellt genom att den dyraste produktionsenheten identifierades på timbasis. Om en billigare produktionsenhet hade potential att leverera högre effekt nästkommande timmar försköts produktionen. Därefter upprepades processen för varje timme under 2018. Efter utförd laststyrning för Gävles fjärrvärmenät hade ca 1 457 MWh förskjutits till en billigare produktionsenhet. Det gav en ekonomisk besparing på 1,0 % av Gävles totala produktionskostnad. Den miljömässiga besparingen visade på en sänkning från 6,1 till 5,9 [g CO2ekv /kWh] sammanlagt 197 ton CO2ekv. På samma sätt utfördes en laststyrning för ett scenario där Gävle och Sandvikens fjärrvärmenät sammankopplats. Vinsten för en laststyrning med Sandviken blev betydligt större med en minskad produktionskostnaden på 3,6 %. Den miljömässiga påverkan sjönk från 8,4 till 7,8 g CO2ekv /kWh sammanlagt 575 ton CO2ekv. För en framtida effektiv laststyrning bör byggnader delas in i olika klasser beroende på byggnadens tidskonstant. Användarmönster för hela fjärrvärmenätet har visat sig svårt att identifiera. Artificiell intelligens kan vara ett alternativ i framtiden för att prognostisera effektuttaget
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Lundh, Magdalena. "Domestic heating with solar thermal studies of technology in a social context and social components in technical studies /." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-101325.
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Piippo, Kaj. "Assessment of Energy Recovery Technology in China : Mechanical ventilation system with energy recovery." Thesis, Eskilstuna : Mälardalen University. School of Sustainable Development of Society and Technology, 2008. http://www.diva-portal.org/smash/get/diva2:127022/FULLTEXT01.
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Strömqvist, Bodil. "Fjärrvärmedriven Absorptionskyla : En ekonomisk undersökning av olika spetslösningar." Thesis, Mittuniversitetet, Institutionen för elektronikkonstruktion, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-42412.
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This independent degree project has been implemented on behalf of FVB Sverige AB in collaboration Sundsvall Energi AB with the initial purpose of mapping manufacturers of hot water driven absorption chillers. After that, several technical solutions are examined to manage the peak load of a theoretical object which cannot produce the cooling power required with only an absorptions chiller, due to limitations in the district heating supply. The market study has shown that the supply of absorption chillers with drive temperatures of 70–90˚C is limited to a few manufacturers. World Energy offers a unit with drive temperatures of 70 ˚C and efficiency (COP) of 0,4. Due to limitations of district heating flow, a unit with drive temperature of 85 ˚C and efficiency of 0,77 is chosen. The technical solutions are dimensioned for a building with a peak power of 264 kilowatt, where the required peak load ranges from 31 to 39 kilowatt. The technical solutions examined are a solar collector system, tap water heat exchanger, and a conventional compressor driven chiller. The solar collectors are dependent on location but use no refrigerants that are affected by the F-gas regulation. The tap water solution consumes large flows of tap water, but the installation is simple. The conventional chiller is not location dependent but uses ozone degrading refrigerants and has a high cost of operation. From an economic perspective the technical solutions are equally profitable with a present net value of approximately 500 000 SEK and pay-back of 13 years. The examination has also shown that the present value is one million crowns in sales of heat and building after a ten-year period. In conclusion the conventional chiller has the biggest prerequisites to be used as a standardised solution for buildings with a bigger cooling load. Based on the technical and economical conditions.
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Nilsson, Daniel. "Fjärrvärmeanslutna passivhus : Fallstudie av värmelaster och innetemperaturer i fyra flerbostadshus." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-17750.
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Intresset kring lågenergibyggnader blir allt större och så kallade passivhus, med god isolering, hög lufttäthet och värmeåtervinning, byggs i allt större utsträckning i Sverige och andra europeiska länder. Vissa frågetecken har dock uppkommit kring inomhusklimatet i husen och risken för både under- och övertemperaturer. En annan viktig aspekt är hur husens egenskaper påverkar värmelasterna och hur detta i sin tur påverkar energiförsörjningssystemet. I detta examensarbete undersöks dessa båda aspekter – värmelastegenskaper och innetemperaturer – i fyra likadana nybyggda flerbostadshus i Falkenberg. Mätvärden från husens tekniska system, inklusive lufttemperaturmätningar i samtliga lägenheter, analyseras. Husen består av totalt 108 lägenheter, värms med fjärrvärme och använder ca 50 kWh/m2 Atemp årligen. Värmelastegenskaperna kännetecknas framförallt av låga effektbehov för både uppvärmning och varmvatten samt relativt stora svängningar över dygnet. Husen tycks vara känsligare för variationer i interntillskott än konventionella hus, vilket leder till regelbundna svängningar i effektbehovet för uppvärmning, med en topp under natten och morgonen. Detta leder till förstärkta svängningar i fjärrvärmenätet, vilket skulle kunna undvikas med hjälp av effektstyrning. Passivhusens stora termiska tröghet talar för en sådan möjlighet. Även innetemperaturen uppvisar regelbundna dygnsvariationer, som kan vara något större än i vanliga hus. Låga temperaturer förekommer tidvis under vintern, men resultaten pekar inte på några brister i de tekniska systemen. Temperaturen på sommaren är inte högre än i andra hus, och övertemperaturer tycks inte vara något stort problem i dessa hus. Det kan dock finnas en möjlighet att minska risken för övertemperaturer ytterligare genom användning av nattkyla under varma perioder. Denna möjlighet kan vara ett sätt att utnyttja passivhusens speciella egenskaper för att ytterligare förbättra konceptet.There is today an increasing interest in low-energy buildings, and the so-called “passive houses” are becoming increasingly popular in Sweden and other European countries. There are however some concerns regarding the indoor climate in these houses, notably the risk of too low indoor temperatures in the winter and too high temperatures in the summer. Another issue is the heat load characteristics of this type of buildings, and how these affect the energy systems. In this thesis, these two aspects – heat load characteristics and indoor temperatures – are analysed in four identical multi-family buildings in Falkenberg, Sweden, using measured values from the buildings’ technical systems and measured indoor air temperatures in all dwellings. The buildings are heated with district heating, comprise 108 dwellings in total and use approximately 50 kWh/m2 annually (space heating, hot water and electricity for building services). The heat loads are mainly characterised by low but varying heat demands for space heating and hot water. The buildings appear to have a higher than usual sensitivity for variations in heat from internal sources and solar gains, leading to regular variations in the heat demand for space heating and fluctuations in the total heat demand. These fluctuations, which may negatively affect the energy system, could be avoided by actively controlling the heat demand for space heating. There are also daily fluctuations in the indoor temperatures, but the buildings perform well in this aspect, with temperatures that stay within the acceptable range most of the time. The summer indoor temperatures do not get higher than in other buildings. A possibility for further improvement within this area could be the use of forced ventilation during the night in hot periods, and hence utilising the buildings’ well insulated and airtight building envelope to keep heat out during the day. This possibility might further improve the passive house concept.
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Lambert, Quentin. "Business Models for an Aggregator : Is an Aggregator economically sustainable on Gotland?" Thesis, KTH, Industriella informations- och styrsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98482.
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Under the determined impulse of the European Union to limit the environmental impact of energy-related services, the electricity sector will face several challenges in coming years. Integrating renewable energy sources in the distribution networks is certainly one of the most urging issues to be tackled with. The current grid and production structure cannot absorb the high penetration shares anticipated for 2020 without putting at risk the entire system. The innovative concept of smart grid offers promising solutions and interesting implementation possibilities. The objective of the thesis is to specifically study the technical and economic benefits that the creation of an aggregator on the Swedish island of Gotland would imply. Comparing Gotland's power system characteristics to the broad variety of solutions offered by demand side management, wind power integration enhancement by demand response appeared particularly suited. A business case, specifically oriented towards the minimisation of transmission losses by adapting the electric heat load of private households to the local wind production was designed. Numerical simulations have been conducted, evaluating the technical and economic outcomes, along with the environmental benets, under the current conditions on Gotland. Sensitivity analyses were also performed to determine the key parameters for a successful implementation. A prospective scenario for 2020, with the addition of electric vehicles, has finally been simulated to estimate the long term profitability of an aggregator on the island. The simulation results indicate that despite patent technical benefits for the distribution network, the studied service would not be profitable in the current situation on Gotland. This, because the transmission losses through the HVDC-cable concern limited amounts of power that are purchased on a market characterized by relatively cheap prices and low volatility. Besides, the high fixed costs the aggregator has to face to install technical equipment in every household constitutes another barrier to its setting up.
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Berthou, Thomas. "Développement de modèles de bâtiment pour la prévision de charge de climatisation et l’élaboration de stratégies d’optimisation énergétique et d’effacement." Thesis, Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0030/document.
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Pour atteindre les objectifs de réduction de consommation et augmenter la flexibilité de la demande des bâtiments, il est nécessaire de disposer de modèles de prévision de charge de climatisation facilement diffusables sur site et performants qui permettent la mise en place de stratégies d’optimisation énergétique et d’effacement. Cette thèse compare plusieurs architectures de modèles inverses (« boite noire », « boite grise »). Un modèle semi-physique d’ordre 2 (R6C2) a été retenu pour prévoir la puissance de climatisation et la température intérieure moyenne en chauffage et en refroidissement. Il permet aussi d’interpréter des situations inédites (effacement), absentes de la phase d’apprentissage. Trois stratégies d’optimisation énergétique et d’effacement adaptées aux contraintes d’exploitation sont étudiées. La première permet d’optimiser la relance en chauffage afin de réduire la consommation et d’atteindre effectivement la température de confort le matin. La seconde stratégie optimise les températures de consigne sur une journée dans un contexte de prix variable de l’énergie, ceci afin de réduire la facture énergétique. Enfin, la troisième stratégie permet au bâtiment de s’effacer en limitant la charge tout en respectant des critères de confort spécifiés. Le modèle R6C2 et les stratégies ont été confrontés à un bâtiment réel (une école élémentaire). L’étude montre qu’il est possible de prévoir la puissance électrique et la température moyenne d’un bâtiment complexe avec un modèle mono-zone ; elle permet d’évaluer les stratégies développées et d’identifier les limites du modèleTo reach the objectives of reducing the energy consumption and increasing the flexibility of buildings energy demand, it is necessary to have load forecast models easy to adapt on site and efficient for the implementation of energy optimization and load shedding strategies. This thesis compares several inverse model architectures ("black box", "grey box"). A 2nd order semi-physical model (R6C2) has been selected to forecast load curves and the average indoor temperature for heating and cooling. It is also able to simulate unknown situations (load shedding), absent from the learning phase. Three energy optimization and load shedding strategies adapted to operational constraints are studied. The first one optimizes the night set-back to reduce consumption and to reach the comfort temperature in the morning. The second strategy optimizes the set-point temperatures during a day in the context of variable energy prices, thus reducing the energy bill. The third strategy allows load curtailment in buildings by limiting load while meeting specified comfort criteria. The R6C2 model and strategies have been faced with a real building (elementary school). The study shows that it is possible to forecast the electrical power and the average temperature of a complex building with a single-zone model; the developed strategies are assessed and the limitations of the model are identified
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Rajdlík, Lukáš. "Návrh vytápění rekreačního domku." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399563.
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This master’s thesis deals with design of different variants of heating and warming of hot service water for holiday building (year-round weekend house, made of bricks). After calculations of the design heat load and heat requirement for heating and warming of hot service water for different types of operations the suitable heat sources are chosen. For heat sources the general design of heating is made. In the end the thesis includes economical analysis for each variant in view of investment and operating costs. The most suitable heat source is chosen from the results of analysis.
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Bouraleh, Maryan. "Techno-economic Potential of Customer Flexibility : A Case Study." Thesis, KTH, Energiteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278079.
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District heating plays a major role in the Swedish energy system. It is deemed a renewable energy source and is the main provider for multi-family dwellings with 90 %. Although the district heating fuel mix consists of majority renewables, a share of 5 % is provided from fossil fuels. To reduce fossil fuel usage and eradicate CO2-emissions from the district heating system new solutions are sought after. In this project, the potential for shortterm thermal energy storage in buildings is investigated. This concept is referred to as customer flexibility. Demand flexibility is created in the district heating system (DHS) by varying the indoor temperature in 50 multi-family dwellings with maximum 1◦C, without jeopardizing the thermal comfort for the tenants. The flexible load makes it possible to store energy shortterm in the building’ envelope. Consequently, heat load curves are evened in production. This leads to a reduction of the peak load in the DHS. Peaks are associated with high costs and environmental impact. Therefore, the potential benefits of customer flexibility are reduced peak production, fuel costs, and CO2-emissions, depending on the fuel mix in the DHS. The project objective is to examine the techno-economic potential of customer flexibility in a specific DHS. The case study is made in a DHS owned by the company Vattenfall, located in the Stockholm area. To evaluate the potential benefits of implementing the concept, seven key performance indicators are chosen. They are peak power, peak fuel usage, produced volume, total fuel cost, fuel cost per produced MWh, climate footprint, and primary energy. Moreover, an in-house optimization model is used to simulate multiple scenarios of the district heating DHS. Different sets of assumptions about the available flexibility in the DHS and the thermal characteristics of the buildings are made. Customer flexibility is modeled as virtual heat storage that can be charged up or down depending on the speed and size of the available storage at a specific outdoor temperature. Simulation results give a maximum peak power reduction of 10.9 % and annual fuel cost reduction between 0.9-3.6 % depending on the scenario. The results found are comparable to values found in similar studies. However, the environmental key performance indicators generated an increase in CO2-emissions and primary energy compared to the baseline scenarios. The result would have looked different if fossil fuels were used in peak production instead of biofuels. The master thesis also aimed to validate assumptions and parameters made in the input data to the optimization model. This was achieved by using results attained from a pilot in the specific DHS. Therefore results generated from the simulations are deemed accurate and confirm that customer flexibility leads to reduced peak production and DHS optimization.Se filen
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Berner, Wik Petter. "Värmereglering utifrån byggnadens tidskonstant i en värmetrög fastighet : Prognostiseringar utav värmeenergianvändningen och dess ekonomiska kostnader." Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-28349.
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För att pådriva utvecklingen mot ett mer hållbart Gävle kommer Gävle Energi AB implementera en ny säsongsbaserad kapacitetsmodell ifrån årsskiftet 2019. Som ska skapa ekonomiska incitament för energieffektivisering i fastigheter inom Gävles fjärrvärmenät. Denna studie kartlägger värmeenergianvändningen i en fastighet som riskerar en förhöjd totalkostnad för fjärrvärmen till följd av den nya prismodellen. Målet med studien är att reducera värmeenergianvändningen utan att investera i fastigheten, vilket möjliggörs genom att värmeenergitillförseln till fastigheten regleras. Genom att programmera ett års historisk data av temperaturer, solinstrålning, el- och värmeeffekter så prognostiseras värmetillförseln på samma sätt som fastighetens styrsystem Kabona Eco-pilot. Styrsystemet tillämpar en flytande inomhustemperatur vilket bidrar till att fastighetens värmetröghet inkluderas i värmeregleringen. Studien inkluderar två prognoser som jämförs med den verkliga värmeenergianvändningen och den nya kapacitetsprismodellen. Prognos 1 är baserad på en årscykel och prognos 2 baseras på intervallet november 2017 till mars 2018. Syftet med prognos 2 är att tillämpa en strategisk värmelaststyrning för att sänka värmekapacitetsbehovet vid -10˚C. Prognos 1 indikerar att en värmeenergibesparing på 26% kan uppnås. Prognosen tar hänsyn till solinstrålning och vissa delar utav den interna värmegenereringen. Utan att Diös fastigheter AB investerat i några energibesparingsåtgärder prognostiseras en besparing på 44 700SEK under ett års drift. Fastigheten har idag energiprestanda energiklass D och kommer efter besparingen att kunna uppnå energiklass C. Prognos 2 indikerar att en kapacitetsreducering kan uppnås motsvarande 46,1% samtidigt som den rörliga värmeenergianvändningen minskar. Totalt sett finns en besparingspotential på 47,8% och 216 700 SEK under perioden 2017-11-01 till 2018-03-31, dock med följd att inomhustemperaturen sjunker.In order to continue the development towards a more sustainable city of Gävle, Gävle Energi AB will implement a new season-based capacity model by the year 2019. It creates economic incentives for energy efficiency in real estate’s within Gävle's district heating network. This report investigates how the heat energy is used for a building that risks an increased heat energy cost, due to the new pricing model. The aim of the study is to reduce the heat energy usage without investing in the building, which is made possible by regulating the thermal energy supply to the building. By programming one year of historical data of temperatures, solar radiation, power- and heat effects the heat supply is forecasted the same way as the building's control system Kabona Eco-pilot is working. The control system applies a floating indoor temperature, which contribute that the thermal inertia of the building is included in the heat load control. The study includes two forecasts that are compared to the actual heat energy use and the new capacity price model. Forecast 1 is based on an annual cycle and forecast 2 is based on the range of November 2017 to Mars 2018. The aim of forecast 2 is to apply a strategic heat load control to reduce the heat capacity needed at -10˚C. Forecast 1 indicates a potential heat energy saving of 26% even though Diös Fastigheter AB does not invest in any energy saving technology. A saving of approximately 44 700 SEK is forecasted for the annual cycle. The building has an energy class D and has the potential to achieve energy class C after the change of control system parameters. Forecast 2 indicates a potential capacity reduction corresponding to 46,1% while the variable heat energy consumption decreases. Overall, there is an approximated heat energy saving potential of 47,8%, which corresponds to 216 700 SEK, during the range of 2017-11-01 to 2018-03-31. Due to the consequence of a lower indoor temperature.
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Lorenz, Manuel [Verfasser]. "Reduction of Heating Loads and Interior Window Fogging in Vehicles / Manuel Lorenz." München : Verlag Dr. Hut, 2015. http://d-nb.info/108075444X/34.
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Kilpatrick, Yvonne Younis. "Daylighting and high efficiency lighting : the effects on heating and cooling loads." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/21810.
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Shi, Hongsen. "Building Energy Efficiency Improvement and Thermal Comfort Diagnosis." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555110595177379.
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Ibrahim, Sherine Taher Mahmoud. "Simulation of air-conditioning loads in electrical power systems." Thesis, University of Bath, 1997. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362265.
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Ruokamo, E. (Enni). "Household preferences for energy goods and services:a choice experiment application." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526221885.
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Abstract This thesis includes three studies on household preferences for energy goods and services. The first study examines determinants of households’ heating system choices using a choice experiment. The choice sets include six main heating alternatives (district heating, ground heat pump, exhaust air heat pump, solid wood boiler, wood pellet boiler, and electric storage heating) that are described by five attributes (supplementary heating systems, investment costs, operating costs, comfort of use and environmental friendliness). The results imply that hybrid heating appears to be accepted among households. The results also reveal differing preferences for the main heating alternatives and show that they are affected by demographic characteristics. The studied attributes also play a significant role when heating systems are being chosen. The second study is a methodological one that extends the analysis of the first study. The second study explores the effect of perceived choice complexity on the randomness of choices in choice experiments. The study investigates how different self-evaluated factors of choice complexity affect mean scale and scale variance. The findings suggest that perceived choice complexity has a systematic impact on the parameters of econometric models of choice. However, differences exist between alternative self-evaluated complexity-related covariates. The results indicate that individuals who report that answering the choice tasks is more difficult have less deterministic choices. Perceptions of the realism of home heating choice options also affect scale and scale variance. The third study utilizes the choice experiment to analyze households’ willingness to participate in demand side flexibility. The study examines whether individuals are willing to time their electricity usage and heating; whether they are interested in dynamic pricing contracts such as real-time pricing, two-rate tariffs, or power-based tariffs; and how emissions reductions affect their choices. The results indicate that households’ sensitivity to restrictions in electricity usage is much stronger than their sensitivity to restrictions in heating. Households also require compensation to choose real-time pricing over fixed fees. The findings suggest that room may exist for new dynamic electricity distribution contracts, such as power-based tariffs, in the market. Other value-creating elements besides monetary compensation also exist that could incentivize households to offer demand side flexibility because households value power system level reductions in CO2 emissionsTiivistelmä Tämä väitöskirja koostuu kolmesta tutkimuksesta, joissa tarkastellaan kotitalouksien preferenssejä energiahyödykkeitä ja -palveluita kohtaan. Ensimmäinen tutkimus keskittyy kotitalouksien lämmitysjärjestelmävalintoihin ja niitä määrittäviin tekijöihin. Tämä tutkimus on tehty valintakoemenetelmällä, jonka valintatilanteet sisältävät kuusi eri päälämmitysjärjestelmävaihtoehtoa (kaukolämpö, maalämpöpumppu, puulämmitys, pellettilämmitys, varaava sähkölämmitys ja poistoilmalämpöpumppu). Päälämmitysjärjestelmiä kuvataan viiden ominaisuuden avulla, jotka ovat tukilämmitysjärjestelmä, investointikustannukset, käyttökustannukset, käyttömukavuus ja ympäristöystävällisyys. Tulosten mukaan kotitalouksien preferenssit päälämmitysjärjestelmävaihtoehtoja kohtaan ovat vaihtelevia. Valintaan vaikuttavat sekä tarkastellut ominaisuudet että kotitalouden demografiset tekijät. Tulokset myös paljastavat, että kotitaloudet suhtautuvat myönteisesti hybridilämmitykseen. Toinen tutkimus on menetelmällinen, missä hyödynnetään ensimmäisen tutkimuksen aineistoa. Tämä tutkimus keskittyy yksilöiden kokeman vastaamisen vaikeuden vaikutuksiin valintakoemenetelmässä. Vastaamisen epätarkkuus tunnistetaan valintakoemenetelmässä skaalan ja skaalavarianssin avulla. Tutkimus tarkastelee, kuinka itsearvioidut vastaamisen vaikeutta mittaavat tekijät vaikuttavat keskimääräiseen skaalaan ja skaalavarianssiin valintojen ekonometrisissa malleissa. Tulosten mukaan koettu vastaamisen vaikeus vaikuttaa systemaattisesti ekonometrisen valintamallin parametreihin. Vastaamisen vaikeutta mittaavien tekijöiden välillä on kuitenkin eroja. Tuloksien perusteella vastaajat, jotka kokevat valintatilanteisiin vastaamisen keskimääräistä vaikeampana, tekevät satunnaisempia valintoja. Myös valintatilanteiden koettu realistisuus vaikuttaa skaalaan ja skaalavarianssiin. Kolmannessa tutkimuksessa arvioidaan kotitalouksien halukkuutta osallistua energian kysyntäjoustoon valintakoemenetelmällä. Tämä tutkimus selvittää ovatko kotitaloudet halukkaitta siirtämään sähkönkulutusta ja lämmitystä, ja kuinka kiinnostuneita he ovat dynaamisista sähkön hinnoittelusopimuksista kuten pörssisähkösopimuksesta, yösähkösopimuksesta tai tehoperusteisesta sopimuksesta. Lisäksi tutkitaan vaikuttavatko järjestelmätason päästövähennykset kotitalouksien valintoihin. Tulosten perusteella kotitaloudet suhtautuvat sähkönkulutuksen rajoituksiin selvästi negatiivisemmin kuin lämmityksen rajoituksiin. Kotitaloudet myös vaativat rahallista korvausta valitakseen pörssisähkösopimuksen kiinteähintaisen sopimuksen sijaan. Tulosten mukaan markkinoilla voisi olla tilaa uudenlaisille sopimustyypeille, kuten tehoperusteiselle vaihtoehdolle. Tulokset osoittavat, että kotitaloudet arvostavat järjestelmätason hiilidioksidipäästövähennyksiä. Täten rahallisen korvauksen lisäksi on olemassa myös muita arvoa luovia tekijöitä lisätä kotitalouksien osallistumista kysyntäjoustoon
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Korolija, Ivan. "Heating, ventilating and air-conditioning system energy demand coupling with building loads for office buildings." Thesis, De Montfort University, 2011. http://hdl.handle.net/2086/5501.
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The UK building stock accounts for about half of all energy consumed in the UK. A large portion of the energy is consumed by nondomestic buildings. Offices and retail are the most energy intensive typologies within the nondomestic building sector, typically accounting for over 50% of the nondomestic buildings’ total energy consumption. Heating, ventilating and air conditioning (HVAC) systems are the largest energy end use in the nondomestic sector, with energy consumption close to 50% of total energy consumption. Different HVAC systems have different energy requirements when responding to the same building heating and cooling demands. On the other hand, building heating and cooling demands depend on various parameters such as building fabrics, glazing ratio, building form, occupancy pattern, and many others. HVAC system energy requirements and building energy demands can be determined by mathematical modelling. A widely accepted approach among building professionals is to use building energy simulation tools such as EnergyPlus, IES, DOE2, etc. which can analyse in detail building energy consumption. However, preparing and running simulations in such tools is usually very complicated, time consuming and costly. Their complexity has been identified as the biggest obstacle. Adequate alternatives to complex building energy simulation tools are regression models which can provide results in an easier and faster way. This research deals with the development of regression models that enable the selection of HVAC systems for office buildings. In addition, the models are able to predict annual heating, cooling and auxiliary energy requirements of different HVAC systems as a function of office building heating and cooling demands. For the first part of the data set development used for the regression analysis, a data set of office building simulation archetypes was developed. The four most typical built forms (open plan sidelit, cellular sidelit, artificially lit open plan and composite sidelit cellular around artificially lit open plan built form) were coupled with five types of building fabric and three levels of glazing ratio. Furthermore, two measures of reducing solar heat gains were considered as well as implementation of daylight control. Also, building orientation was included in the analysis. In total 3840 different office buildings were then further coupled with five different HVAC systems: variable air volume system; constant air volume system; fan coil system with dedicated air; chilled ceiling system with embedded pipes, dedicated air and radiator heating; and chilled ceiling system with exposed aluminium panels, dedicated air and radiator heating. The total number of models simulated in EnergyPlus, in order to develop the input database for regression analysis, was 23,040. The results clearly indicate that it is possible to form a reliable judgement about each different HVAC system’s heating, cooling and auxiliary energy requirements based only on office building heating and cooling demands. High coefficients of determination of the proposed regression models show that HVAC system requirements can be predicted with high accuracy. The lowest coefficient of determination among cooling regression models was 0.94 in the case of the CAV system. HVAC system heating energy requirement regression models had a coefficient of determination above 0.96. The auxiliary energy requirement models had a coefficient of determination above 0.95, except in the case of chilled ceiling systems where the coefficient of determination was around 0.87. This research demonstrates that simplified regression models can be used to provide design decisions for the office building HVAC systems studied. Such models allow more rapid determination of HVAC systems energy requirements without the need for time-consuming (hence expensive) reconfigurations and runs of the simulation program.
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Chung, Tse-Ming. "Prediction of zone temperatures, cooling loads and illuminances from numerical simulation of the interaction between fluorescent lighting and HVAC systems." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/33238.
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A numerical model has been developed for the dynamic simulation of heat and radiation transfer from lamps and ballasts in an enclosure. The model, named LITEAC1, calculates temperatures, cooling loads and illuminances at each simulation time step. LITEAC1 is an improvement upon existing models in the literature in the following aspects: it performs dynamic simulation for all nodes without assuming that some nodes are massless; it calculates illuminances on room surfaces; and it runs faster on a desktop computer. In order to refine the simulation of the two-way interaction between lighting and HVAC systems, a fluorescent lamp positive column discharge model, named LAMPPC, has been incorporated into LITEAC1 to improve calculation of the conversion of input electrical energy into light, thermal radiation and heat. LAMPPC employs established principles in plasma physics to quantify the energy conversion processes.
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Graux, Nicolas. "Caractérisation et modélisation des propriétés à la fatigue à grand nombre de cycles des aciers cémentés à partir d'essais d'auto-échauffement sous sollicitations cycliques." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0104.
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Le dimensionnement en fatigue à grand nombre de cycles d'un contact roulant entre des éléments ayant subi un traitement thermochimique de cémentation s'avère rapidement complexe.D'une part le traitement de cémentation apporte une hétérogénéité de propriété dans les couches supérieures de la pièce qui dépend du protocole utilisé. D'autre part le chargement de contact roulant est un chargement complexe dont le mode de défaillance en fatigue s'initie en sous-couche.Afin de limiter le temps de la caractérisation des champs de propriétés en fatigue, l'utilisation des mesures d'auto-échauffement sous sollicitation cyclique ainsi que leur interprétation par un modèle probabiliste à deux échelles est proposé. Néanmoins de par l'hétérogénéité du matériau et de par la particularité du chargement il peut s'avérer délicat d'appliquer une telle méthode d'évaluation. ll est alors proposé d'explorer ces deux difficultés de manière séparé.Pour prendre en compte l'hétérogénéité matériaux, un protocole d'analyse de courbe d'auto-échauffement basé sur une variante d'un modèle probabiliste à deux échelles et sur les mesures de taux de carbone a été proposé. Les paramètres du modèle ont été identifiés sur une classe d'acier via des mesures d'auto-échauffement réalisées sur des éprouvettes représentatives de l'hétérogénéité du au traitement de cémentation. Enfin le modèle a été validé par comparaison avec des points de fatigue expérimentaux.En ce qui concerne le chargement de contact roulant, les difficultés pour réaliser une mesure d'auto-échauffement ont mené à effectuer une première campagne de mesure sur le cas intermédiaire du contact répété. A l'aide d'un modèle analytique simple, l'évolution du champ de température a pu être reliée à un terme source de chaleur moyen dont le lien avec les mécanismes de fatigue reste à démontrer. Finalement, des prototypes de machine de contact roulant dédiés aux mesures d'auto-échauffement ont été proposés. Les mesures réalisées sur ces dernières et leur interprétation laissent à penser qu'il sera possible d'identifier des propriétés de fatigue à partir de mesure d'auto-échauffementThe rolling contact fatigue prediction between two carburizing part quickly becomes complex.On one hand, the carburizing treatment give heterogeneous properties in surface layer depending on the treatment protocol. On the other hand, the rolling contact load is a complex load with a fatigue initiation in the sub-layer. To limit the duration of the field fatigue properties characterization, self-heating measurements under cycle load are used and their interpretation by a probabilistic two scales model is proposed. Nevertheless applying this fatigue evaluation method on heterogeneous material and for rolling contact load can be difficult. ln first approach those difficulties are split.To take into account the material heterogeneity, an analysis based on a variation of one probabilistic two scales model and on carbon rate measurement is proposed. Model parameters are identified on one steel class with self-heating measurement made on specimens representative of carburizing material heterogeneity. Finally the model is validated by comparison with experimental fatigue point.Making self-heating measurement for rolling contact load is complex. Consequently a first self-heating measurement campaign is made on the intermediary case of repeated contact. With a simple analytic model, the temperature field evolution can be linked to a mean heat source whose link with fatigue mechanism must be proven. Finally, rolling contact machine prototypes are proposed. Self-heating measurement made on those prototypes and their interpretation suggest that it will be possible to identify fatigue properties with self-heating measurement
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Hallqvist, Karl. "Högtempererat borrhålslager för fjärrvärme." Thesis, Uppsala universitet, Naturresurser och hållbar utveckling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231586.
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The district heating load is seasonally dependent, with a low load during periods of high ambient temperature. Thermal energy storage (TES) has the potential to shift heating loads from winter to summer, thus reducing cost and environmental impact of District Heat production. In this study, a concept of high temperature borehole thermal energy storage (HT-BTES) together with a pellet heating plant for temperature boost, is presented and evaluated by its technical limitations, its ability to supply heat, its function within the district heating system, as well as its environmental impact and economic viability in Gothenburg, Sweden, a city with access to high quantities of waste heat. The concept has proven potentially environmentally friendly and potentially profitable if its design is balanced to achieve a good enough supply temperature from the HT-BTES. The size of the heat storage, the distance between boreholes and low borehole thermal resistance are key parameters to achieve high temperature. Profitability increases if a location with lower temperature demand, as well as risk of future shortage of supply, can be met. Feasibility also increases if existing pellet heating plant and district heating connection can be used and if lower rate of return on investment can be accepted. Access to HT-BTES in the district heating network enables greater flexibility and availability of production of District Heating, thereby facilitating readjustments to different strategies and policies. However, concerns for the durability of feasible borehole heat exchangers (BHE) exist in high temperature application.Värmebehovet är starkt säsongsberoende, med låg last under perioder av högre omgivningstemperatur och hög last under perioder av lägre omgivningstemperaturer. I Göteborg finns en stor mängd spillvärme tillgängligt för fjärrvärmeproduktion sommartid när behovet av värme är lågt. Tillgång till säsongsvärmelager möjliggör att fjärrvärmeproduktion flyttas från vinterhalvår till sommarhalvår, vilket kan ge såväl lönsamhet som miljönytta. Borrhålsvärmelager är ett förhållandevis billigt sätt att lagra värme, och innebär att berggrunden värms upp under sommaren genom att varmt vatten flödar i borrhål, för att under vinterhalvåret användas genom att låta kallt vatten flöda i borrhålen och värmas upp. I traditionella borrhålsvärmelager används ofta värmepump för att höja värmelagrets urladdade temperatur, men på grund av höga temperaturkrav för fjärrvärme kan kostnaden för värmepump bli hög. I denna rapport föreslås ett system för att klara av att nå höga temperaturer till en lägre kostnad. Systemet består av ett borrhålsvärmelager anpassat för högre temperaturer (HT-BTES) samt pelletspannor för att spetsa lagrets utgående fluid för att nå hög temperatur. Syftet med rapporten är att undersöka potentialen för detta HT-BTES-system med avseende på dess tekniska begränsningar, förmåga till fjärrvärmeleverans, konsekvenser för fjärrvärmesystemet, samt lönsamhet och miljöpåverkan. För att garantera att inlagringen av värme inte är så stor att priset för inlagrad värme ökar väsentligt, utgår inlagringen från hur mycket värme som kyls bort i fjärrvärmenätet sommartid. I verkligheten finns betydligt mer värme tillgänglig till låg kostnad. När HT-BTES-systemet producerar fjärrvärme, ersätts fjärrvärmeproduktion från andra produktionsenheter, förutsatt att HT-BTES-systemets rörliga kostnader är lägre. I Göteborg ersätts främst naturgas från kraftvärme, men också en del flis. Kostnadsbesparingen beror på differensen för total fjärrvärmeproduktionskostnad med och utan HT-BTES-systemet. Undersökningen visar att besparingen är större om HT-BTES-systemet placeras i ett område där det är möjligt att mata ut fjärrvärme med lägre temperatur. Om urladdning från HT-BTES kan ske med hög temperatur ökar också besparingen. Detta sker om lagrets volym ökar, om avståndet mellan borrhål minskar eller om värmeöverföringen mellan det flödande vattnet i borrhålen och berggrunden ökar. Dessa egenskaper för lagret leder också till minskade koldioxidutsläpp. Storleken på besparingen beror dock i hög grad på hur bränslepriser utvecklas i framtiden. Strategiska fördelar med HT-BTES-systemet inkluderar; minskad miljöpåverkan, robust system med lång teknisk livslängd (för delar av HT-BTES-systemet), samt att inlagring av värme kan ske från många olika produktionsenheter. Dessutom kan positiva bieffekter identifieras. Undersökningen visar att HT-BTES-systemet har god potential att ge lönsamhet och minskad miljöpåverkan, och att anläggning och drift av lagret kan ske utan omfattande lokal miljöpåverkan. Det har också visats att de geologiska förutsättningarna för HT-BTES är goda på många platser i Göteborg, även om lokala förhållanden kan skilja sig åt. För att nå lönsamhet för HT-BTES-systemet krävs en avvägning på utformning av lagret för att nå hög urladdad temperatur utan att investeringskostnaden blir för stor. Undersökningen visar att om anslutning av HT-BTES-systemet kan ske mot befintlig anslutningspunkt eller till befintlig värmepanna kan investeringskostnaden minska och därmed lönsamheten öka. Placering av HT-BTES-systemet i områden med risk för överföringsbegränsningar kan också minska behovet av att förstärka fjärrvärmenätet, och således bidra till att minska de kostnader som förstärkning av nätet innebär. Betydelsefulla parametrar för att nå lönsamhet för HT-BTES-system inkluderar dessutom kostnaden för inlagrad värme liksom vilket vinstkrav som kan accepteras. Tillgång till HT-BTES möjliggör ökad nyttjandegrad och flexibilitet för fjärrvärmeproduktionsenheter, och därmed ökad anpassningsmöjlighet till förändrade förutsättningar på värmemarknaden. Dock återstår att visa att komponenter som klarar de höga temperaturkraven kan tillverkas till acceptabel kostnad.
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Lorenz, Manuel [Verfasser], Thomas [Akademischer Betreuer] Sattelmayer, and Klaus [Akademischer Betreuer] Bengler. "Reduction of Heating Loads and Interior Window Fogging in Vehicles / Manuel Lorenz. Betreuer: Thomas Sattelmayer. Gutachter: Thomas Sattelmayer ; Klaus Bengler." München : Universitätsbibliothek der TU München, 2015. http://d-nb.info/1080592253/34.
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Kotík, Libor. "Konstrukce sila na cukr." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227611.
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The matter of this thesis is static design and examination of prestressed storage tank to 50000 tons of sugar. Computational model of the steel roof structure is processed and its effect on the silos. Loads is provided of sugar. Optimal design is performed and assessment ultimate and serviceability limit state reinforced concrete and prestressing horizontal silo wall including local load. Next, it is performed the design of a reinforced concrete of the plane bed and column and assessment at the ultimate limit state. The thesis is also drawing documentation, technical report and visualization of construction process. The aim of this work is to the design of the main components based on the required storage capacity tank, mechanical properties of the stored material and technical amenities.
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Yusupov, Timor. "The effect of occupant comfort preferences and use patterns on the space heating loads in the context of the next home unit." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43916.
Full textAbstract:
The occupant plays an important role in residential energy consumption, and likewise, a critical part in energy conservation. Studies have shown that energy consumption in similar houses can vary significantly due to the occupant’s behaviour and household characteristics. Nevertheless, very few studies have focused on identifying the occupant driven parameters responsible for energy variations or on quantifying their impact.
This study analyzes the impact of the occupant’s preferences of temperature settings, the number of thermostats used, the door operations, the use of window curtains, and the fenestration’s effect on the heating loads of a residential unit. This analysis quantifies the impact of each occupant related parameter as a function of various factors, including occupancy patterns, interior layouts, orientation, and volumetric occupation.
The research answers the following questions: How significant is the influence of occupant behaviour on space heating loads? How does this vary with changes in occupancy patterns and spatial configurations? How significant is the influence of changes in fenestration on space heating loads relative to occupant behaviour?
Seventeen design scenarios are generated, through which the impact of the occupant behaviour and her/his design preferences is evaluated. The results, which are generated using IES VE software, identify the impact of each occupant related parameter on the heating loads using the Next Home Unit as a model house, located in a Toronto climate.
In general, the results show that the occupancy patterns, interior layout, and volumetric occupation can significantly change the impact of each occupant related parameter on a unit’s heating loads. On average, reducing a unit’s
temperature from 23℃ to 18℃ or installing low e double glazed windows, most significantly reduces the heating loads. The lowest impact on the heating loads is found when changing the fenestration area and leaving the doors open.
The study shows that an occupant’s actions -- such as keeping doors close, heating the room only when occupied, reducing the unit’s temperature, and installing low e glazing -- can reduce the energy required for heating. However, as the research shows, the effect of the above actions can significantly vary due to occupancy patterns, interior layout, and volumetric occupation.
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Arzamendia, Lopez Juan Pablo. "Métholodogie de conception des matériaux architecturés pour le stockage latent dans le domaine du bâtiment." Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0060/document.
Full textAbstract:
L'utilisation de systèmes de stockage par chaleur latente constitue une solution permettant l'effacement du chauffage d'un bâtiment résidentiel pendant les périodes de forte demande. Une telle stratégie peut avoir pour objectif le lissage des pics d'appel en puissance du réseau électrique. Cependant, la faible conductivité des matériaux à changement de phase (MCP) qui constituent ces systèmes et le besoin d'une puissance de décharge importante imposent l'utilisation de matériaux dits "architecturés" afin d'optimiser la conductivité équivalente des matériaux stockeurs. Nos travaux s'intéressent plus particulièrement à la méthodologie pour la conception de matériaux pour ces systèmes afin de satisfaire aux exigences de stockage d'énergie et de puissance de restitution. La méthodologie proposée dans ces travaux de thèse est dénommé « Top-down methodology ». Cette méthodologie comporte trois échelles : l'échelle bâtiment (top), l'échelle système et l'échelle matériau (down). L'échelle bâtiment a comme objectif de spécifier le cahier des charges. A l'échelle système, des indicateurs de performance sont définis. Enfin, à l'échelle matériau, l'architecture du matériau solution est proposée. Un outil numérique modélisant le système de stockage par chaleur latente de type échangeur de chaleur air/MCP à été développé pour évaluer les indicateurs de performance. Ce modèle numérique est vérifié avec un cas analytique et validé par comparaison avec des données expérimentales. La méthodologie développée est mise en œuvre dans un deuxième cas d'étude pour le même type de système de stockage. L'analyse du système via les nombres adimensionnels permet d'obtenir des indicateurs de performance du système. A l'issue de cette étape, les propriétés matériaux et fonctionnelles optimales du système sont donc connues. Enfin, un matériau architecturé est alors proposé afin de satisfaire les exigences du système de stockage. Nous montrons alors que par l'intermédiaire d'une plaque sandwich contenant des clous et du MCP les propriétés matériaux nécessaires sont obtenues. De plus, afin de satisfaire aux exigences en termes de propriétés fonctionnelles, le design du système est modifié en ajoutant des ailettes sur les surfaces d'échange. Nous montrons que avec 20 ailettes de 3mm d'épaisseur sur la surface d'échange de la planche à clous, le chauffage est effacé pendant 2h lors de la période de forte demande journalière pendant l'hiverThe use of energy storage systems that exploit latent heat represents a promising solution to erase the heating demand of residential buildings during periods of peak demand. Equipping a building with such components can contribute to the goal of peak shaving in terms of public electricity grid supply. Significant drawbacks, however, are the low thermal conductivity of Phase Change Materials (PCM) that typically constitute such systems,and the requirement for a high rate of discharge. Consequently, the use of so-called architectured materials has been put forward as a means to optimize the effective conductivity of storage materials. Our work is focused upon the development of a methodology to design optimal materials for such systems that meet the criteria of energy storage and energy output. A so-called “top-down metholodogy” was implemented for the present work. This approach includes three scales of interest: building (top), system and material (down). The aim of the building scale analysis is to formulate a set of general design requirements. These are complemented by performance indicators, which are defined at the scale of the system. Finally, at the scale of the material, the architecture of the identified material is elaborated. A numerical simulation tool was developed to determine performance indicators for a latent heat energy storage system comprising of an air/PCM heat exchanger. This model was tested against a benchmark analytical solution and validated though comparison to experimental data. The developed methodology is applied to the specific case of an air/PCM exchanger latent-heat energy storage system. The system is analysed through the study of dimensionless numbers, which provide a set of design indicators for the system. As a result of this stage, the optimal material and functional properties are thus identified. Finally, an architectured material is proposed that would satisfy the design requirements of the storage system. We demonstrate that an arrangement composed of a sandwich of planar layers with nails and PCM can offer the required material properties. Furthermore, in order to meet the desired functional properties, the system design is modified by the addition of fins at the exchange surfaces. With the addition of 20 fins of 3mm thickness attached to the exchange surface of the sandwich panel, the storage system eliminated the heating demand for 2 hours during the period of high daily demand in winter
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Du, Hu. "Modelling of building performance under the UK climate change projections and the prediction of future heating and cooling design loads in building spaces." Thesis, Northumbria University, 2012. http://nrl.northumbria.ac.uk/5837/.
Full textAbstract:
New climate change projections for the UK were published by the United Kingdom Climate Impacts Programme in 2009. They form the 5th and most comprehensive set of predictions of climate change developed for the UK to date. As one of main products of UK Climate Projections 2009 (UKCP09), the Weather Generator, can generate a set of daily and hourly future weather variables at different time periods (2020s to 2080s) and carbon emission scenarios (low, medium and high) on a 5 km grid scale. In a radical departure from previous methods, the 2009 Projections are statistical-probabilistic in nature. A tool has been developed in Matlab to generate future Test Reference Year (TRY) and Design Reference Years (DRY) weather files from these Projections and the results were verified against results from alternative tools produced by Manchester University and Exeter University as well as with CIBSE’s Future Weather Years (FWYs) which are based on earlier (4th generation) climate change scenarios and are currently used by practitioners. The Northumbria tool is computationally efficient and can extract a single Test Reference Year and 2 Design Reference Years from 3000 years of raw data in less than 6 minutes on a typical modern PC. It uses an established ISO method for generating Test Reference Year data and an alternative method of constructing future Design Reference Years data is proposed. Fifteen different buildings have been identified according to alternative usage, thermal insulation, user activity and construction details. Besides these variants, the buildings were chosen specifically because they either exist, or have received planning consent and so represent ‘real’ UK building examples. Two investigations were then carried out based on the 15 case study buildings. The first involved applying TRYs generated for London, Manchester and Edinburgh for a variety of carbon emission scenarios at time horizons of 2030, 2050 and 2080. The TRYs were developed into a weather data format readable by the EnergyPlus energy simulation program to simulate summertime internal comfort (operative) temperatures, cooling demands and winter heating demands. All results were compared with a control data set of nominally current weather data, together with the same results produced using the alternative weather data generators of Manchester University, Exeter University and the CIBSE FWYs. Results revealed a good agreement between the various methods and show that significant increases in internal summer operative temperatures in non-air-conditioned buildings can be expected as time advances through this century, as well as increased air conditioning cooling energy demands and small reductions in winter heating energy demand. The second investigation involved generating time series of design internal peak summertime operative temperatures, design cooling demands and design winter heating demands for the same conditions as the first investigation. The results were then used to develop a simplified estimation method to predict future design cooling loads using multiple regressions fitting to selected data from the DRY simulation inputs and outputs. The simplified estimation method forms a useful tool for estimating how future cooling design loads in buildings are likely to evolve over time. It also provides a basis for designers and practitioners to determine how buildings constructed today will need to be adapted through life to cope with climate change.