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. / Environmental challenges and the increasing in electric demand show the importance of considering other form of production while maintaining the safety and reliability of the electrical system. The electrical power systems stability lays on a fundamental constraint: supply and demand must be equal at each instant, so, different solutions are already in place, these solutions include controlling generators’ production during peak periods. But, power units (mainly nuclear, thermal, hydro) capacities are not always sufficient and flexible to follow the demand variations during these periods; an alternative solution to this insufficiency is to make the demand following the electrical power generation by providing bulks of electrical power to the power system by curtailing consumer’s electric load consumption. Such a solution that represents a new organization in the power system industry can be done by Demand Side Management (DSM) actions. The aim of the thesis is to study the possibility to offer services to the electrical system by applying control actions called DR (Demand Response) on different types of electric loads. These DR actions represent partial interruptions of electrical loads’ consumption and especially thermal loads’ consumption.Our choice was based on the thermal electric loads because they store heat respectively in air and water, which can be restored during the control period or interruption. However, there is a negative effect that follows the control of these type of loads because the reduced energy during curtailment period is deferred at the time of reconnection, this deferred power takes the form of a power peak named CLPU (Cold Load Pick-Up), which appears at the time of reconnection. The CLPU is a problem that must be managed, and its magnitude depends on the type of control actions and on the electric system conditions (ie: contingency or failure of a generating unit). In the thesis, the CLPU is controlled and optimized as well as the load reduction during curtailment period. The contribution of control actions in balancing mechanisms and the effect produced on the secondary control of frequency are analyzed.

The European Union is planning to greatly decrease energy consumption during the coming decades. The ultimate goal is to create sustainable communities that are energy neutral. One way of achieving this challenging goal may be to use efficient hydronic (water-based) heating systems supported by heat pumps. The main objective of the research reported in this work was to improve the thermal performance of wall-mounted hydronic space heaters (radiators). By improving the thermal efficiency of the radiators, their operating temperatures can be lowered without decreasing their thermal outputs. This would significantly improve efficiency of the heat pumps, and thereby most probably also reduce the emissions of greenhouse gases. Thus, by improving the efficiency of radiators, energy sustainability of our society would also increase. The objective was also to investigate how much the temperature of the supply water to the radiators could be lowered without decreasing human thermal comfort. Both numerical and analytical modeling was used to map and improve the thermal efficiency of the analyzed radiator system. Analyses have shown that it is possible to cover space heat losses at low outdoor temperatures with the proposed heating-ventilation systems using low-temperature supplies. The proposed systems were able to give the same heat output as conventional radiator systems but at considerably lower supply water temperature. Accordingly, the heat pump efficiency in the proposed systems was in the same proportion higher than in conventional radiator systems. The human thermal comfort could also be maintained at acceptable level at low-temperature supplies with the proposed systems. In order to avoid possible draught discomfort in spaces served by these systems, it was suggested to direct the pre-heated ventilation air towards cold glazed areas. By doing so the draught discomfort could be efficiently neutralized.     Results presented in this work clearly highlight the advantage of forced convection and high temperature gradients inside and alongside radiators - especially for low-temperature supplies. Thus by a proper combination of incoming air supply and existing radiators a significant decrease in supply water temperature could be achieved without decreasing the thermal output from the system. This was confirmed in several studies in this work. It was also shown that existing radiator systems could successfully be combined with efficient air heaters. This also allowed a considerable reduction in supply water temperature without lowering the heat output of the systems. Thus, by employing the proposed methods, a significant improvement of thermal efficiency of existing radiator systems could be accomplished. A wider use of such combined systems in our society would reduce the distribution heat losses from district heating networks, improve heat pump efficiency and thereby most probably also lower carbon dioxide emissions. / <p>QC 20131029</p>

The subject of this diploma thesis is to design space heating system for building with five floors, where the first above ground floor is used as commercial space. Designed building have one underground floor and four above ground floors. Diploma thesis is designed as project of Building Service, specifically that of Heating. This diploma thesis contains calculations of the design heat load, design of radiators and others heating surfaces, hydraulic balancing, generation of domestic hot water, design of heat source, calculations of safety devices and pumps design. Part of this diploma thesis is also conceptual design of regulation.

This thesis's main objective is to conduct a comparison study between measured values and simulated results of a demonstrator, of the intelligent home energy management (iHEM) project. The comparison helps to validate the simulation. TRNSYS software is used for the design. In this study, only the thermal energy side of the project is considered. In which system-level (both domestic hot water (DHW), space heating (SH)) and component level (solar collector, gas boiler) are considered as the parameters to compare. An attempt is made to optimize both system-level and component-level simulation outputs with measured values by adopting measured boundary conditions as simulation inputs.During the comparison, the DHW loop simulation design is modified. The measured data were given as input files for simulation, replacing the estimated values used before. This is done to optimize the simulation output with measured data. In the space heating loop (SH), the simulated building model’s parameters were changed to optimize the SH demand. After the system-level validation and optimization, the component level comparison is carried out. For this, the simulation output of solar thermal collectors and gas boiler are compared with measured values. The solar collector loop in the simulation is modified to optimize the simulated results. The seasonal and yearly efficiencies of the collector have been calculated. Solar supply fraction and gas boiler supply fraction is also determined. For the comparison, graphs are plotted for three different weeks, representing the spring, summer, and winter months of 2018.The final optimized simulation output of DHW demand is 7% less than the measured value. Even after optimizing the Space heating loop (SH), the simulated building demand is 17% more heat than the demonstrator building. The simulation's solar collector output is optimized close to the measured values. The simulated gas boiler produces 19% more than the demonstrator system to meet excess SH demand in the simulation (including losses). The overall yearly collector efficiency calculated for measured and simulated values are 58% and 50%, respectively. The estimated solar collector supply fraction and gas boiler supply fraction is 26%, 76% for measured, and 23%, 81% for simulation, respectively.

Rostoucí světová poptávka po méně efektivních zdrojích energie vede ke zvýšení zájmu o kogenerační technologie v sektoru domácností. Pomocí této technologie lze významně snižovat množství znečišťujících látek emitovaných při výrobě elektřiny a tepla pro domácnosti. Kogenerační systémy v sektoru domácností nabízí možnost produkce jak užitného tepla a elektřiny z jednoho zdroje paliva, např. motorové nafty či zemního plynu. Tato práce se zaměřuje na analýzu možností užití kogeneračních a tri-generačních technologií ke zlepšení efektivity využití primárního zdroje energie, zejména v zemích severní Afriky. První část práce se orientuje na obecné definice v oblasti elektroenergetiky, aktuální i budoucí výhled energetické bilance v Libyi. Následující kapitoly se věnují kogeneračním a tri-generačních systémům, jejich charakteristikám se zaměřením na technické parametry, výhodám a nevýhodám těchto systémů a jejich dalšímu rozvoji. Hlavní část práce se zabývá problematikou spotřeby typických rodinných domů ve třech nejdůležitějších městech Libye. Dále předkládá citlivostní analýzu, která je zaměřená na výpočet množství energie vyžadované k pokrytí energetických potřeb typického domu (vytápění, ohřev vody a klimatizace) a porovnání naplnění těchto potřeb při uvažování technických a ekonomických hledisek. Výsledky práce budou využity pro tvorbu pokladů pro Libyjské energetické úřady.

In view of the fact that most of the synthetic refrigerants, in case of leakage or release, are harmful to the environment by contributing in global warming or depleting stratospheric ozone layer, many research works have been done recently to find alternative refrigerants posing no or negligible threat to the environment. Among alternative refrigerants, ammonia, a natural refrigerant with zero Global Warming Potential (GWP) and Ozone Depletion Potential (ODP), can be a sensible choice.Although ammonia has been used for many years in large industrial systems, its application in small units is rare. In this project a small heat pump with about 7 kW heating capacity at -5 °C and +40 °C evaporation and condensation temperatures is designed and built to work with ammonia as refrigerant. The heat pump is expected to produce enough heat to keep a single-family house warm in Sweden and to provide tap hot water for the house. After successful completion of this project, it is planned to install the heat pump in a house to test it throughout a heating season to study its performance in real working conditions.Since ammonia is flammable and toxic in high concentrations, the refrigerant charge is tried to be kept low in the heat pump to reduce the risk of fire or poisoning in case of unwanted release of refrigerant to the surroundings. The compact design of the heat pump helps reducing the refrigerant charge. Besides, considering the limited space normally reserved for installation of a heat pump in a house, the compact design of the heat pump is necessary.

This thesis's main objective is to conduct a comparison study between measured values and simulated results of a demonstrator, of the intelligent home energy management (iHEM) project. The comparison helps to validate the simulation. TRNSYS software is used for the design. In this study, only the thermal energy side of the project is considered. In which system-level (both domestic hot water (DHW), space heating (SH)) and component level (solar collector, gas boiler) are considered as the parameters to compare. An attempt is made to optimize both system-level and component-level simulation outputs with measured values by adopting measured boundary conditions as simulation inputs.During the comparison, the DHW loop simulation design is modified. The measured data were given as input files for simulation, replacing the estimated values used before. This is done to optimize the simulation output with measured data. In the space heating loop (SH), the simulated building model’s parameters were changed to optimize the SH demand. After the system-level validation and optimization, the component level comparison is carried out. For this, the simulation output of solar thermal collectors and gas boiler are compared with measured values. The solar collector loop in the simulation is modified to optimize the simulated results. The seasonal and yearly efficiencies of the collector have been calculated. Solar supply fraction and gas boiler supply fraction is also determined. For the comparison, graphs are plotted for three different weeks, representing the spring, summer, and winter months of 2018.The final optimized simulation output of DHW demand is 7% less than the measured value. Even after optimizing the Space heating loop (SH), the simulated building demand is 17% more heat than the demonstrator building. The simulation's solar collector output is optimized close to the measured values. The simulated gas boiler produces 19% more than the demonstrator system to meet excess SH demand in the simulation (including losses). The overall yearly collector efficiency calculated for measured and simulated values are 58% and 50%, respectively. The estimated solar collector supply fraction and gas bo

Global energy demand is increasing every year dramatically, which results global warming due to increased greenhouse gas emissions. So, to be environmentally friendly and sustainable, Sweden’s energy policy targets to reach 100 % renewable energy share in 2040. Already, Sweden achieved 50 % renewable energy share in 2012 which was targeted to achieve by 2020. Integration of solar heating system in residential sector, for space heating (SH) and domestic hot water (DHW), was one of the reasons for this achievement. Considerably, several numbers of solar heating systems were installed in houses until 2011. Thus, solar heating system could be a step towards to reach 2040s target. In 2011, detached Swedish house was installed with solar combi-system (SCS) which was designed to use 53% of solar energy. The main aim of this thesis is to analyze the thermal performance of SCS and correlation with its simulated system performance which is done in five steps.First step is the collection of measured data from the system for specific period one year from April 2019 to March 2020 and determined other unknown energy values in that data. In the second step, unknown data are calculated using scientific equations with information from users and reliable assumptions. Consequently, the analysis of measured data shows huge uncertainties. It follows to the third step as sensitivity analysis to enhance the assumption values. Thus, analyzed results are tabulated with reliable parameters and solar fraction (SF) of the measured data is calculated. In the fourth step, SH of the house is considered as reference to build a system model in Polysun simulation software, and the modelled results are verified with analyzed results. In the final step, system model is simulated by changing one-year weather profile to 10 years average weather profile. Thus, analyzed results and simulated results are compared to evaluate the performance. The real system has the SF of 52 % after sensitivity analysis whereas the simulated system showed the SF with percentage difference around 15 %.

Global energy demand is increasing every year dramatically, which results global warming due to increased greenhouse gas emissions. So, to be environmentally friendly and sustainable, Sweden’s energy policy targets to reach 100 % renewable energy share in 2040. Already, Sweden achieved 50 % renewable energy share in 2012 which was targeted to achieve by 2020. Integration of solar heating system in residential sector, for space heating (SH) and domestic hot water (DHW), was one of the reasons for this achievement. Considerably, several numbers of solar heating systems were installed in houses until 2011. Thus, solar heating system could be a step towards to reach 2040s target. In 2011, detached Swedish house was installed with solar combi-system (SCS) which was designed to use 53% of solar energy. The main aim of this thesis is to analyze the thermal performance of SCS and correlation with its simulated system performance which is done in five steps.First step is the collection of measured data from the system for specific period one year from April 2019 to March 2020 and determined other unknown energy values in that data. In the second step, unknown data are calculated using scientific equations with information from users and reliable assumptions. Consequently, the analysis of measured data shows huge uncertainties. It follows to the third step as sensitivity analysis to enhance the assumption values. Thus, analyzed results are tabulated with reliable parameters and solar fraction (SF) of the measured data is calculated. In the fourth step, SH of the house is considered as reference to build a system model in Polysun simulation software, and the modelled results are verified with analyzed results. In the final step, system model is simulated by changing one-year weather profile to 10 years average weather profile. Thus, analyzed results and simulated results are compared to evaluate the performance. The real system has the SF of 52 % after sensitivity analysis whereas the simulated system showed the SF with percentage difference around 15 %.

Over the last two centuries, there has been a continual evolution of how occupied rooms are heated, with inventors competing to design new heating devices. In particular, there is a wide range of convector types, which vary in shape, size, design, material, operating medium and application. With approximately 190 million convectors installed in the UK alone, the question arises regarding the dependencies on the efficiency of heat distribution through convector-induced filling flows. A standard approach to evaluate convector performance is based on the convector strength only, the implication being the stronger the convector the better the performance. This work has gone beyond the limits of a stereotypical assessment in pursuit of answers regarding the physics of convector-induced filling and a new objective method to evaluate the efficiency of this transient process. The ultimate goal has been to provide a deep understanding of filling and stratification induced by a convector, in order to heat rooms rapidly and effectively. An experimental facility has been designed that approximates dynamic similarity between the experimental set-up and a real-life room with a convector. In the experiments, a rectangular sectioned water tank represents a room and a saline source rectangular sectioned panel with sintered side walls provides a convector representation. Experiments have been performed in water with a saline solution to ensure high Rayleigh numbers. Diagnostic techniques involve a combination of a shadowgraph method, a dye-attenuation method, direct salinity measurements and a new application of Particle Image Velocimetry (PIV). Interesting insight into convector-induced buoyancy-driven flows has been gained. As a result, new guidelines aimed at heating rooms more rapidly and effectively have been proposed. The key outcome that can be immediately applied is that, for a given convector strength, heat distribution with height can be improved by adjusting the convector position. For instance, faster filling leading to more uniform heat distribution occurs in rooms with convectors detached from side walls, due to large-scale mixing flows in the early period of filling. Also shorter convectors relative to the room height, positioned close to the floor level, promote faster and more uniform filling. An attempt to describe the transient filling has been made and to do so statistical methods, application specific, have been developed. As a result, the empirical equations describing both the filling rates in different stages of filling and the development of stratification have been derived, which rank the governing parameters, based on their importance, as either dominant or subordinate. Two dominant parameters governing filling flows are the non-dimensional accumulation parameter B and the Rayleigh number ΔRa, which are related to the convector strength. The impact of these two parameters is constant throughout the process. The parameters accounting for the system geometry and filling time (T) are subordinate parameters. Their impact, visible in the early period, decreases as filling continues.