Modeling of heat transfer using Dymola. In this report a evaporator, economizer and superheater where modeled. The report describes how the models where modeled and what input was most suitable for a accurate model.

The master's thesis describes the design of the steam boiler, which burns biomass with heat output of 6 MW. The required parameters of the steam are a temperature of 300 °C and a pressure of 2,5 MPa. The thesis is gradually devoted to stoichiometric calculations through heat losses and boiler efficiency, to the design of the combustion chambre, heat exchangers and pressure losses. Part of the thesis is drawing documentation of the boiler.

Subject of this thesis is design of the steam generator for modular reactor. The dissertation consist of the theoretical part, where are described heat-exchangers and steam generators used in nuclear power plants. Second part contains theoretical calculations in the first approach (thermal, hydraulic and strenght calculation). In the next part are particular variants of steam generator selected. For the final variant are necessary calculations (introduced above) and drawings of selected parts are done. In the final statement is technical solution evaluated, and the parameters of the steam generator are compared with actually used steam generators.

This diploma thesis deals with the constructional and calculation design of boiler for blast furnace and coke gas mixture combustion, including sizing of the heating surfaces. The opening section is dedicated to a brief characterization of burned fuels. The following chapter shows the parameters and composition of the resulting fuel mixture. The main part of this thesis involves; determining the stoichiometric amount air required for combustion and the resulting flue gas, determining the boiler efficiency and steam production rate, calculations regarding the combustion chamber and the detailed design of the individual heat exchangers. At the end of the thesis the heat balance of the entire boiler is verified. Drawing documentation of boiler is also part of this diploma thesis.

The thesis deals with the design of a grate steam boiler which has natural circulation and is determined for combustion of wood chips. The boiler has a capacity of 45 t/h and produces superheated steam with the output parameters of 3,5 MPa and 450 °C at the 125 °C feed water temperature. Stoichiometric calculations and the flue gases enthalpy calculations are based on the composition of the specified fuel. The efficiency and fuel consumption of the boiler is also determined. The thesis mainly focuses on the thermal calculation and geometric design of the individual heat transfer surfaces of the boiler. The drawing documentation of the steam boiler is available in the attachment of the thesis.

The residential building sector plays an important role in combating climate change in Canada. Many energy efficiency solutions along with new building energy standards have been implemented to improve building energy performance. However, their effects on energy saving and GHG emissions reduction vary due to the complexity of the building systems and the variability of their operational conditions. This work quantifies such variability in both energy efficiency devices and building energy standards implementation, respectively. The first study in this dissertation assesses the energy savings from sensible heat recovery in a residential apartment suite in various locations across Canada. A series of detailed building energy performance models are developed in TRNSYS. The HVAC system’s annual energy consumption is simulated and the results are compared with and without HRV for each climate zone. The results show the heating energy savings of employing the HRV vary from 17 to 34% depending on the winter climatic conditions; while, the building cooling energy use can be increased due to the undesired thermal recovery occurring in the HRV during the cooling season. The second study investigates the free cooling potential of outside air in various Canadian cities. A series of thermal models developed using BEopt 2.8 for a hypothetical single-family house with various window-to-wall ratios and building aspect ratios simulates hourly building cooling load profiles. The free cooling potential is analyzed by comparing the maximum available and the actual usable free cooling for various building features and different climates. The results indicate that, although free cooling is widely available in most areas of Canada during the summer and shoulder seasons, only 17-42% of such free cooling is usable without the use of thermal storage. The last study examines the effects of two building energy standards - the BC Step Code and the Passive House criteria - on reductions in residential household space heating GHG emissions under different enforcement scenarios. The space heating energy and the GHG emissions are estimated using the forecast growth of single detached households for the period from 2020 to 2032. The results show that the space heating GHG emissions can be reduced by 77% and 89%, respectively if the BC Step Code or the Passive House criteria is implemented in Canada. It is also found the impacts of energy code on GHG emission mitigation are less significant in regions where the carbon intensity of the dominant heating fuels is low. / Graduate

Tesis por compendio / [ES] Esta tesis doctoral presenta un estudio de compresores scroll con inyección de vapor (SCVI) para bombas de calor que operan en climas fríos o para aplicaciones de calentamiento de agua a alta temperatura. Para ello, se comparó experimentalmente un SCVI con un compresor de dos etapas de pistones (TSRC) trabajando con R-407C en condiciones extremas. La comparación se realizó en términos de eficiencias del compresor, capacidad, COP y rendimientos estacionales tanto para el modo calefacción como para el modo refrigeración. Los resultados proporcionan una idea general sobre el rango de aplicación de los compresores estudiados y sobre las diferencias en los rendimientos de los compresores. Sin embargo, se identificaron varias limitaciones en la caracterización de los compresores y en el análisis del ciclo. Esto motivó a profundizar en el estudio del ciclo de compresión de dos etapas y sus componentes. El siguiente paso fue realizar un análisis teórico de los ciclos de compresión de dos etapas para aplicaciones de calefacción, en donde se identificó a la presión intermedia y a la relación de inyección como los parámetros del sistema más influyentes sobre el COP. La presión intermedia se optimizó para dos configuraciones de inyección (tanque de separación y economizador) utilizando varios refrigerantes. Basándose en los resultados de la optimización, se propuso una correlación que permite obtener la presión intermedia óptima del ciclo, considerando la influencia del subenfriamiento a la salida del condensador. Además, se analizó la influencia del diseño de los componentes del sistema sobre el COP del ciclo. Posteriormente, el estudio se profundizó a nivel de componentes. El factor más crítico en el sistema es el rendimiento del compresor. Por lo tanto, el siguiente paso fue evaluar la influencia de varios sistemas de compresión con inyección de vapor sobre el COP. Se tomaron en cuenta tres tecnologías de compresores, un SCVI, un TSRC y un compresor scroll de dos etapas (TSSC). Estas tecnologías de compresores fueron caracterizadas y modeladas para estudiar su rendimiento. Para ello, se propuso una nueva metodología para caracterizar compresores scroll con inyección de vapor. Esta metodología permite evaluar el rendimiento del compresor independientemente del mecanismo de inyección que se utiliza en el ciclo. Se identificó una correlación lineal entre la relación de inyección de refrigerante y la relación de compresión intermedia. Esta correlación se utiliza para determinar el flujo másico de inyección en función de la presión intermedia. Posteriormente, se propuso un modelo semi-empírico de compresores scroll y una metodología para extender dicho modelo para compresores scroll con inyección de vapor. Los modelos fueron ajustados y validados usando datos experimentales de cuatro compresores scroll trabajando con R-290 y un SCVI trabajando con R-407C. Finalmente, se comparó un SCVI con dos compresores de dos etapas, un TSSC y un TSRC, trabajando en condiciones extremas. Se optimizó la relación de volúmenes de los compresores de dos etapas. Los resultados muestran que, en las condiciones nominales de funcionamiento (Te=-15 °C, Tc=50 °C), la relación de volúmenes óptima del TSSC es 0.58, y del TSRC es 0.57. El TSSC consigue un COP 6% mayor que el SCVI y un COP 11.7% mayor que el TSRC. Bajo un amplio rango de condiciones de operación, el SCVI presenta una mejor eficiencia y COP para relaciones de presión inferiores a 5. Para relaciones de presión más altas, el TSSC presenta mejor rendimiento y consigue una temperatura de descarga más baja. Se concluye que el SCVI es una solución fácil de implementar, desde el punto de vista del mecanizado, y que permite extender el mapa de trabajo de los compresores de una etapa. Sin embargo, los resultados muestran que la compresión en dos etapas consigue mejorar en mayor medida el COP del ciclo y la capacidad, con una mayor redu / [CA] Aquesta tesi doctoral presenta un estudi de compressors scroll amb injecció de vapor (SCVI) per a bombes de calor que operen en climes freds o per a aplicacions d'escalfament d'aigua a alta temperatura. Per a això, es va comparar experimentalment un SCVI amb un compressor de dues etapes de pistons (TSRC) treballant amb R-407C en condicions extremes. La comparació es va realitzar en termes d'eficiències del compressor, capacitat, COP i rendiments estacionals tant per al mode calefacció com per al mode refrigeració. Els resultats proporcionen una idea general sobre el rang d'aplicació dels compressors estudiats i sobre les diferències en els rendiments dels compressors. No obstant això, es van identificar diverses limitacions en la caracterització dels compressors i en l'anàlisi del cicle. Això va motivar a aprofundir en l'estudi del cicle de compressió de dues etapes i els seus components. El següent pas va ser realitzar una anàlisi teòrica dels cicles de compressió de dues etapes per a aplicacions de calefacció, on es va identificar la pressió intermèdia i la relació d'injecció com els paràmetres del sistema més influents sobre el COP. La pressió intermèdia es va optimitzar per a dues configuracions d'injecció (tanc de separació i economitzador) utilitzant diversos refrigerants. Basant-se en els resultats de l'optimització, es va proposar una correlació que permet obtindre la pressió intermèdia òptima del cicle, considerant la influència del subrefredament a l'eixida del condensador. A més, es va analitzar la influència del disseny dels components del sistema sobre el COP del cicle. Posteriorment, l'estudi es va aprofundir a nivell de components. El factor més crític en el sistema és el rendiment del compressor. Per tant, el següent pas va ser avaluar la influència de diversos sistemes de compressió amb injecció de vapor sobre el COP. Es van prendre en compte tres tecnologies de compressors, un SCVI, un TSRC i un compressor scroll de dues etapes (TSSC). Aquestes tecnologies de compressors van ser caracteritzades i modelades per a estudiar el seu rendiment. Per a això, es va proposar una nova metodologia per a caracteritzar compressors scroll amb injecció de vapor. Aquesta metodologia permet avaluar el rendiment del compressor independentment del mecanisme d'injecció que s'utilitza en el cicle. Es va identificar una correlació lineal entre la relació d'injecció de refrigerant i la relació de compressió intermèdia. Aquesta correlació s'utilitza per a determinar el flux màssic d'injecció en funció de la pressió intermèdia. Posteriorment, es va proposar un model semi-empíric de compressors scroll i una metodologia per a estendre aquest model per a compressors scroll amb injecció de vapor. Els models van ser ajustats i validats utilitzant dades experimentals de quatre compressors scroll treballant amb R-290 i un SCVI treballant amb R-407C. Finalment, es va comparar un SCVI amb dos compressors de dues etapes, un TSSC i un TSRC, treballant en condicions extremes. Es va optimitzar la relació de volums dels compressors de dues etapes. Els resultats mostren que, en les condicions nominals de funcionament (Te=-15 °C, Tc=50 °C), la relació de volums òptima del TSSC és 0.58, i del TSRC és 0.57. El TSSC aconsegueix un COP 6% major que el SCVI i un COP 11.7% major que el TSRC. Sota un ampli rang de condicions d'operació, el SCVI presenta una millor eficiència i COP per a relacions de pressió inferiors a 5. Per a relacions de pressió més altes, el TSSC presenta millor rendiment i aconsegueix una temperatura de descàrrega més baixa. Es conclou que el SCVI és una solució fàcil d'implementar, des del punt de vista del mecanitzat, i que permet estendre el mapa de treball dels compressors d'una etapa. No obstant això, els resultats mostren que la compressió en dues etapes aconsegueix millorar en major mesura el COP del cicle i la capacitat, amb una major reducció de la / [EN] This Ph.D. thesis presents a study of scroll compressors with vapor-injection (SCVI) for heat pumps operating in cold climates or in high-temperature water heating applications. To do so, firstly, an SCVI was experimentally compared with a two-stage reciprocating compressor (TSRC) working with R-407C under extreme conditions. The comparison was made in terms of compressor efficiencies, capacity, COP, and seasonal COP, both for heating and cooling modes. The results give a general idea about the application range of the studied compressors and the differences in the compressors' performance. Nevertheless, several restrictions in the compressors' characterization and the cycle analysis were identified. This motivated us to deepen in the study of the two-stage compression cycle and its components. The next step was performing a theoretical analysis of two-stage compression cycles for heating applications, where the intermediate pressure and the injection ratio were identified as the most influential system parameters on the COP. The intermediate pressure was optimized for two vapor-injection configurations (flash tank and economizer) using several refrigerants. Based on the optimization results, a correlation was proposed that allows obtaining the optimal intermediate pressure of the cycle, considering the influence of the subcooling at the condenser outlet. In addition, a theoretical analysis of the influence of the design of the system components on the COP of the cycle was performed. Once the thermodynamic analysis of the two-stage cycle was carried out, the study was deepened at the component level. The most critical factor in the system is the compressor performance. Hence, the next step was evaluating the influence of several compression systems with vapor-injection on the COP. Three compressor technologies were taken into account, an SCVI, a TSRC and a two-stage scroll compressor (TSSC). These compressor technologies were characterized and modeled in order to study their performance. To do so, a new methodology to characterize SCVI was proposed. This methodology allows evaluating the compressor performance independently of the injection mechanism used in the cycle. A linear correlation was identified between the refrigerant injection ratio and the intermediate compression ratio. This correlation is used to determine the injection mass flow as a function of the intermediate pressure. Then, a semi-empirical model of scroll compressors and a methodology to extend the model for scroll compressors with vapor-injection was proposed. The models were adjusted and validated using experimental data from four scroll compressors working with R-290 and an SCVI compressor working with R-407C. Finally, an SCVI was compared with two two-stage compressors, a TSSC, and a TSRC, working in extreme conditions. The displacement ratio of the two-stage compressors was optimized. Results show that, at the nominal operating conditions (Te=-15 °C, Tc=50 °C), the optimal displacement ratio of the TSSC is 0.58, and of the TSRC is 0.57. The TSSC achieves 6% larger COP than the SCVI and 11.7% larger COP than the TSRC. Under a wide range of operating conditions, the SCVI presents a better efficiency and COP for pressure ratios below 5. For higher-pressure ratios, the TSSC presents better performance and achieves lower discharge temperature. It is concluded that the SCVI is an easy solution to implement from the point of view of machining, which allows extending the working map of the single-stage compressors. However, the results show that the two-stage compression technology gets further improve the COP of the cycle and the capacity, with a greater reduction of the discharge temperature operating under extreme conditions. / I thank the financial support provided by the Secretaría de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT) of Ecuador, through the international scholarship program for postgraduate studies “Convocatoria Abierta 2013 Segunda Fase, Grant No 2015-AR37665”. / Tello Oquendo, FM. (2019). Study of scroll compressors with vapor-injection for heat pumps operating in cold climates or in high-temperature water heating applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/120473 / Compendio

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<p>With rising temperatures, urbanization, population growth, improving economic wellbeing, decarbonization and electrification efforts, the demand for space cooling and heating equipment is continuously increasing around the world. To counteract the effect of rising demand for air conditioners and heat pumps on total energy consumption, peak electricity demand, and emissions, it is crucial to promote the development and market penetration of energy-efficient systems. Establishing minimum energy performance standards (MEPS), energy labeling and utility programs are some of the effective and tested methods for achieving this goal. The technical basis for these energy efficiency standards is a testing and rating procedure for estimating equipment seasonal performance from laboratory tests. Although the current rating procedures provide standardized metrics to compare different equipment performances, they fail to appropriately characterize the field representative performance of systems by not considering the effects of: 1) test unit embedded controls, thermostat, and realistic interactions with the building load and dynamics; 2) different climate zones and building types; and 3) and other integrated accessories for improving energy efficiency such as economizer for rooftop units (RTUs). Therefore, current approaches for performance ratings neither incentives the development and implementation of improved system and control designs nor consumers with a metric that represents the advanced systems' actual energy savings. To address this, a load-based testing methodology that enables dynamic performance evaluation of equipment with its integrated controls, thermostat, and other accessories was recently proposed. The test methodology is based on the concept of emulating the response of a representative building conditioned by the test unit in a test lab using a virtual building model. </p> <p>In this work, the proposed load-based testing methodology was further extended, evaluated, and validated for residential heat pumps to integrate it into next-generation energy efficiency testing and rating procedures and to serve as a tool for engineers to develop and validate improved control algorithms in a laboratory setting. Further, a load-based testing method for evaluating the dynamic performance of RTUs with integrated economizers was also developed and demonstrated.</p> <p>A load-based testing approach previously developed for residential cooling equipment is extended for heat pump heating-mode and demonstrated for a variable-speed system. The heat pump's typical dynamic behaviors are captured along with controller imperfections that aren't reflected in current testing approaches. Further, a comprehensive comparison was performed between the proposed load-based testing approach to the current steady-state testing approach in the U.S., AHRI 210/240, based on performance evaluation of three residential variable-speed heat pumps to understand the differences and their significance for the next-generation rating procedure. For cooling mode, steady-state testing estimates higher seasonal performance, but for heating mode, the steady-state testing approach estimates higher seasonal performance for warmer climates and is comparable for colder climates. The load-based testing methodology was validated by comparing the laboratory performance of a heat pump to that of a residential building in a controlled environment. The virtual building modeling approach for building loads and thermal dynamics effectively captured these characteristics of the house. The heat pump's cycling rate response with run-time fraction, which represents the unit's overall dynamic response, matched well between lab load-based tests and house tests. The test unit's COP difference for cooling and heating tests was within 3% between the two facilities, except for 9% in 95°F and 6% in 104°F cooling dry-coil test intervals. To evaluate the applicability of the developed load-based testing methodology as next-generation rating standards, its repeatability and reproducibility were assessed based on multiple heat pump round-robin tests conducted in two labs. Overall, reasonable to good repeatability was observed in load-based test results in both labs, however, poor reproducibility was observed except for one heat pump heating mode results. A root cause analysis of the observed differences along with recommendations for a next-generation rating approach are presented. This work aided in the development of a CSA (Canadian Standards Association) standard EXP07:19 and its subsequent revision for equipment rating based on load-based testing.</p> <p>The application of the load-based testing methodology as a tool for the development and evaluation of a residential heat pump controller design was demonstrated. Further, a load-based testing methodology was developed and demonstrated for the dynamic performance evaluation of RTUs with integrated economizers in a test laboratory setting. Recommendations for future work to further develop and improve the repeatability, reproducibility, and representativeness of the load-based testing and rating approach for residential and commercial air conditioners and heat pumps are summarized at the end of the dissertation. </p>