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Integration of CAD, CAM and computer aided inspection for the development of complex shaped productsJiang, Zongchuan January 2001 (has links)
No description available.
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Contribution to the modelling of refrigeration systems / Contribution à la modélisation de systèmes de réfrigérationCuevas Barraza, Cristian 15 December 2006 (has links)
The main objective of this study is to propose and to validate simplified models to simulate the performance of refrigeration systems.
The proposed modelling approach of the system is modular: the compressor is modelled by a simple and physical model that takes into account the heat transfers and the un-matching of internal and external pressure ratio for the scroll compressors. The evaporator is modelled as a two zones heat exchanger on the refrigeration side (one for the two phases zone and the other one for superheated gas) and finally the condenser is assumed to be divided into three zones (de-superheating, two-phase and the sub-cooling).
The compressor model was already developed by other author; here it is only validated using three scroll compressors and two reciprocating ones. The main differences are the conditions at which these compressors are tested: 20 bar at the supply and 40 at the exhaust.
The condenser and evaporator models are the main contribution of this study. These models use the geometry and the correlation from the literature to calculate the global heat transfer coefficient on each zone. In the case of the condenser, a mean void fraction model is used to determinate the condenser subcooling as function of the refrigerant charge or vice-versa.
The refrigeration system model is validated with experimental results obtained on each component and the whole system in five different test benches. The results show a very good agreement between the measured and predicted main outputs of the system.
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Conversion of a scroll compressor to an expander for organic Rankine cycle: modeling and analysisOralli, Emre 01 December 2010 (has links)
Conversion of a scroll compressor to an expander for organic Rankine Cycle: modeling and analysis / UOIT
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Experimental Analysis of Positive Displacement Compressors for Refrigerator Freezer and Air Conditioning ApplicationCai S Rohleder (6251672) 14 May 2019 (has links)
<div>Vapor compression cycles are the most common method used to provide cooling to environments. In the residential area, refrigerator/freezers as well as air conditioners/heat pumps almost exclusively use vapor compression cycles. The driving force behind a vapor compression cycle is the compressor, where a variety of compressor types are used in the same application. While reciprocating compressors are found in the majority of refrigerator/freezers, scroll compressors are predominantly used in residential air conditioners. Yet other compressors have emerged as replacements due to increased efficiency. A R134a oil-free prototype scroll compressor and a R134a reciprocating compressor are operated in a hot-gas bypass test stand under refrigerator/freezer conditions to compare performance. Additionally, a R407C scroll compressor and a R410A rotary compressor are operated in a compressor calorimeter under air conditioning/heat pump conditions to compare performance. Experimental results show that the reciprocating compressor far outperforms the prototype scroll compressor in the refrigerator/freezer application, while the performance between the scroll and rotary compressors are almost equal in the air conditioning application.</div><div>Pressure fluctuation at compressor discharge is also measured in the compressor calorimeter to determine feasibility of applying a novel muffling design to air conditioning compressors, although it was found that traditional muffling methods currently used are effective to a degree such that this new method is unwarranted. Data from the compressor calorimeter is also used to investigate the accuracy of the AHRI 540 10-Coefficient Correlation compressor map in predicting performance both inside and outside the tested operating conditions. The AHRI 10-Coefficient Correlation achieves high accuracy inside tested operating conditions but is inept in extrapolating performance, where other map correlations are more accurate.</div>
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Experimental investigation of scroll based organic Rankine systemsTarique, Md. Ali 01 April 2011 (has links)
In this thesis, an experimental research is conducted on scroll-based Organic Rankine Cycle (ORC) focusing on the expansion process. An important feature of the ORC is the ability to utilize low or moderate temperature heat sources derived from renewable energy such as concentrated solar radiation, biomass/biofuels combustion streams, geothermal heat and waste heat recovery. The ORC is more appropriate than steam Rankine cycle to generate power from low capacity heat sources (5-500 kW thermal). For example, expansion of superheated steam from 280oC/1000 kPa to a pressure corresponding to 35oC saturation requires a volume ratio as high as 86, whereas for the same operating conditions toluene shows an expansion ratio of 6 which can be achieved in a single stage turbine or expander.
The objective of this work is to experimentally study the performance of a selected refrigeration scroll compressor operating in reverse as expander in an ORC. To this purpose, three experimental systems are designed, built and used for conducting a comprehensive experimental programme aimed at determining the features of the expansion process. In preliminary tests the working fluid utilized is dry air while the main experiments are done with the organic fluid R134a.
Experimental data of the scroll expander are collected under different operating conditions. Power generation in various conditions is analyzed in order to determine the optimum performance parameters for the scroll expander. In addition, thermodynamic analysis of the system is conducted through energy and exergy efficiencies to study the system performance.
Based on the experimental measurements, the optimum parameters for an ORC cycle operating with the Bitzer-based expander-generator unit are determined. The cycle energy and exergy efficiencies are found 5% and 30% respectively from a heat source of 120oC. / UOIT
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Experimental analysis of variable capacity heat pump system equipped with vapour injection and permanent magnet motorAwan, Umer Khalid January 2012 (has links)
This study analyzes the performance of variable capacity heat pump scroll compressor which is equipped with vapour injection and permanent magnet motor. Refrigerant used in the system is R410A. The study is divided in two phases. In first phase, tests are carried out for heat pump without vapour injection. Heat pump’s performance including COPs, heating/cooling capacities, inverter losses, heat transfer behaviour in condenser/evaporator are analyzed. Inverter losses increase but the ratio of inverter losses to the total compressor power decreases with increase in compressor speed. Electromechanical losses of compressor are much higher than the inverter losses and so make most part of the total compressor losses (summation of inverter and electromechanical losses). In second phase benefits of vapour injection are analyzed. For vapour injection, heat pump’s performance is evaluated for two different refrigerant charges: 1.15kg and 1.28kg. It is noted that heat pump performs better for refrigerant charge 1.15kg even at lower compressor speeds as compared to refrigerant charge 1.28kg. For refrigerant charge 1.15kg, heat pump COP cool with vapour injection increases by an average of 10.66%, while COP heat increases by an average of 9.4%, at each compressor speed except for 30Hz, as compared to conventional heat pump cycle with no vapour injection. Similarly refrigerant temperature at outlet of compressor also reduces with vapour injection which leads to the better performance of heat pump.
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Experimental evaluation of air-to-water propane heat pumps with 40kW heating capacityXu, Tianhao January 2015 (has links)
This thesis presents the experimental work on testing the seasonal performance of a 40 kW air-to-water propane heat pump, as a part of the research project Next Heat Pump Generation working with Natural fluids (NxtHPG) that has been carried out in ‘Applied thermodynamics and refrigeration Division’ in the department of Energy Technology, KTH. The thesis work involves three parts: preparation of the HP unit test rigs, experimental campaign and the evaluation of test results. In the first part, the set-up of the measurement device and necessary modifications to the heat pump unit as well as the test rigs have been completed to create an accurate measuring environmental for the experimental campaign. During the second stage, two series of experimental campaign have been done in the heating mode of the heat pump unit, and satisfactory results have been obtained in parts of the test conditions. Finally, the evaluation on the system performance as well as the behaviors of the components is discussed. The variation between experimental results and the simulation conducted by IMST-ART model is within reasonable range, proving that the heat pump unit has been working in good conditions. The compressor is proved to have been performing as manufacturer expected. However, some further investigations on the behaviors of the heat exchangers and expansion valve, such as superheat oscillation, are recommended be carried out in the future work. The completion of the rest of tests in which minus air temperature should be maintained and the ones with the desuperheater working should be done as well. / Next generation heat pump working with natural fluids
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Performance comparison between reciprocating and scroll compressor heat pumps with R600a refrigerantKRONSTRÖM, CHRISTOFER January 2021 (has links)
A performance comparison of heat pumps using a scroll (Sanden) and a reciprocating (Bitzer) compressor was conducted experimentally. The refrigerant used was R600a (isobutane). The heat pump components were evaluated performance-wise through: volumetric and isentropic efficiency of the compressors; the UA-value of the condensers and evaporators; sensible enthalpy differences between the liquid and the suction line in the internal heat exchanger; and overall heat pump system comparison as the coefficient of performance. The Bitzer heat pump had existing measuring devices and equipment installed, and it was already filled with refrigerant. The Sanden heat pump required installation of equipment and measuring devices and a refrigerant refill. The refrigerant charge was decided according to the criteria of the lowest compressor speed, which had an effect of overcharge for higher speeds. The measurements included the temperature of water and refrigerant, pressure of the refrigerant, water volume flow, and compressor power. The heat pumps performances were then evaluated based on these parameters. The Sanden compressor showed higher volumetric efficiency than the Bitzer compressor, for the two lower (out of three) speeds of the compressor. The isentropic efficiency of the Bitzer compressor proved to be higher for all pressure ratios out of the three speeds respectively. The condenser in the Bitzer heat pump showed proper UA-values based on the temperature differences between refrigerant and heat sink. The UA-values of the Sanden heat pump condenser did not increase with compressor speed which then gave a larger temperature difference between refrigerant and heat sink, for the two higher compressor speeds. The evaporators had a similar issue with the temperature difference between refrigerant and heat source, which also showed on the UA-values. The internal heat exchanger in the Bitzer heat pump had a larger sensible enthalpy difference on the suction side compared to the liquid side, when condenser subcooling was low, indicating that some fraction of refrigerant was being condensed instead. The Sanden heat pump instead had higher condenser subcooling and the sensible enthalpy difference showed to be very low in the internal heat exchanger. Finally, the coefficient of performance showed to be slightly higher in the Bitzer heat pump for almost all evaluated condensation and evaporation temperatures. / En jämförelse av prestandan för två värmepumpar, en med scroll- (Sanden) och en med kolvkompressor (Bitzer) har gjorts. Köldmedlet som användes var R600a (isobutan). Komponenterna och hur deras prestanda blev utvärderad följer här: kompressorernas volymetriska och isentropisk verkningsgrad; kondensorns och förångarens UA-värden; den sensibla entalpiskillnaden mellan gas- och vätskeledning i den interna värmeväxlaren; en övergripande jämförelse av värmepumparna i form av deras värmefaktor. Värmepumpen med Bitzerkompressor utvärderades med befintliga komponenter och mätutrustning, och en redan fylld mängd köldmedium. Värmepumpen med Sandenkompressor installerades med mätutrustning och komponenter, och fylldes med köldmedium. Mängden köldmedium bestämdes utifrån kriterier för det lägsta varvtalet på kompressorn, vilket visade sig ge en för stor mängd köldmedium vid de högre varvtalen. Mätningarna inkluderade temperatur på vatten och köldmedium, köldmediets tryck, vattnets volymflöde samt kompressorns effektbehov. Prestandan för värmepumparna är sedan utvärderad utifrån dessa data. Sandenkompressorn visade en högre volymetrisk verkningsgrad för de två lägre (av tre) hastigheterna utvärderade i experimenten, jämfört med Bitzer. Den isentropiska verkningsgraden var högre i Bitzerkompressorn för samtliga tryckförhållanden för de tre respektive hastigheterna. Kondensorn i Bitzervärmepumpen uppvisade goda UA-värden, baserat på temperaturskillnaderna mellan köldmedium och värmesänka. Kondensorn i Sandenvärmepumpen visade ingen förbättring av UA-värden när kompressorns hastighet ökade, vilket i sin tur gav upphov till stora temperaturskillnader mellan köldmediet och värmesänkan. Förångarna i båda värmepumparna uppvisade liknande problem med höga temperaturskillnader mellan värmekälla och köldmedium, vilket även deras UA-värden visade. Den interna värmeväxlaren i Bitzervärmepumpen visade större skillnad i den sensibla entalpin på sug- jämfört med vätskesidan, när underkylningen i kondensorn var låg, vilket indikerade på att en del av köldmediet istället kondenserade. I Sandenvärmepumpen var kondensorns underkylning högre vilket då uppvisade en liten skillnad i den sensibla entalpin mellan de båda sidorna. Slutligen så visade Bitzervärmepumpen en något högre värmefaktor än Sandenvärmepumpen för nästan alla utvärderade kondenserings- och förångningstemperaturer.
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Improving the acoustics comfort of the 6-metre-long BLUEBUS electric bus / Förbättrad akustisk komfort i den 6 meter långa elbussen BLUEBUSFlochlay, Corentin January 2024 (has links)
With the electrification of the automotive industry, vehicles tend to be quieter than their internal combustion engine counterparts. Because of this phenomenon, noises and vibrations that were initially imperceptible appear and affect the overall comfort level of the driver and the passengers. It can also lead to structural fatigue witch results in an increase of maintenance and repair costs. In the case of the BlueBus 6m IT3, a disturbance is encountered with the Scroll compressor, placed atop of the driver’s cabin, which supplies the braking system and the suspensions. When running at low speed, it vibrates and enters in resonance with the bus structure. This thesis aims to reduce the resonance between the bus frame and the compressor by focusing on the characteristics frequencies of both systems. The vibrations of the compressor and the bus roof were measured for distinct stiffnesses and positions of the anti-vibration mounts and at the two compressor running speeds: 2000 rpm and 2900 rpm. The Sound Pressure Level (SPL) inside the driver’s cabin and close to the compressor was also acquired to evaluate and compare the different configurations. A reduction of 2 dBA was achieved by increasing the stability of the motor-compressor assembly with a new support made up of wider mounts. The anti-vibration mounts of a shore hardness of 40 Sh were the more efficient with another 2 dBA decrease and a vibration of the roof quartered. A modal analysis confirmed the presence of a coupling between the compressor and the first cavity mode of the bus structure at low speed leading to amplified noise in the bus. Another analysis was performed on a modified compressor structure including the evolutions resulting from the tests. It results in a decoupling between the compressor and the bus frame and reduced bracket vibrations under loads at low speed. / Med elektrifieringen av fordonsindustrin tenderar fordonen att bli tystare än sina motsvarigheter med förbränningsmotorer. På grund av detta fenomen uppstår ljud och vibrationer som från början var omöjliga att uppfatta, vilket påverkar den allmänna komfortnivån för föraren och passagerarna. Det kan också leda till strukturell utmattning, vilket i sin tur leder till ökade underhålls- och reparationskostnader. I fallet med BlueBus 6m IT3 har en störning uppstått i scroll-kompressorn, som är placerad ovanför förarhytten och försörjer bromssystemet och fjädringarna. När den körs med låg hastighet vibrerar den och går i resonans med bussens struktur. Denna avhandling syftar till att minska resonansen mellan bussramen och kompressorn genom att fokusera på de karakteristiska frekvenserna för båda systemen. Vibrationerna från kompressorn och bussens tak mättes för olika styvheter och positioner för antivibrationsfästena och vid de två kompressorhastigheterna: 2000 rpm och 2900 rpm. Ljudtrycksnivån i förarhytten och i närheten av kompressorn mättes också för att utvärdera och jämföra de olika konfigurationerna. En minskning med 2 dBA uppnåddes genom att öka stabiliteten hos motorkompressorenheten med ett nytt stöd som bestod av bredare fasten. De vibrationsdämpande fästena med en shore-hårdhet på 40 Sh var mest effektiva med ytterligare en minskning på 2 dBA och en vibration av taket på en fjärdedel. En modalanalys bekräftade förekomsten av en koppling mellan kompressorn och den första kavitetsmodusen i bussstrukturen vid låga varvtal, vilket ledde till förstärkt buller i bussen. En annan analys utfördes på en modifierad kompressorstruktur som inkluderade de utvecklingar som framkom vid testerna. Det resulterade i en frikoppling mellan kompressorn och bussramen och minskade vibrationer i konsolen under belastning vid låga hastigheter.
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Study of scroll compressors with vapor-injection for heat pumps operating in cold climates or in high-temperature water heating applicationsTello Oquendo, Fernando Mauricio 05 April 2021 (has links)
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 / TESIS / Compendio
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