Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"R410a"”.
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Effect of longitudinal micro fin tube enhancement in evaporation of R410A
… an internal diameter of 6.3 mm. The study used R410A at a saturation temperature of 10 °C running at mass fluxes from 100 to 250 kg/m2-s, heat fluxes from 4 to 14 kW/m2, and qualities from 0.1 to 0.8. The testing facility had a 15 cm long test section heated by a secondary heated water loop, a …
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Comparison of refrigerants R410a and R404a for use in low temperature applications: A computer model study
… a perspective for comparison of refrigerant R410a with R404a. As R410a is now widely used commercially, further knowledge is desired on how different an R410a system is from established refrigerant systems and any possibilities for retrofitting. This thesis uses a computer model simulation to …
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Oil Retention and Pressure Drop in Horizontal and Vertical Suction Lines with R410A / POE ISO 32
… to circulate POE (polyolester) oil and R410A at a controlled mass flux, OCR (oil in circulation ratio), and apparent superheat, and to directly measure the pressure drop and mass of oil retained in horizontal and vertical suction lines. The bulk vapor velocity and overall void fraction …
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Carbon Dioxide and R410A Flow Boiling Heat Transfer, Pressure Drop, and Flow Pattern in Horizontal Tubes at Low Temperatures
… the evaporation temperature of -30°C. Also, R410A and R22 flow boiling heat transfer coefficients and pressure drop in a macro-scale (6.1 mm) tube were measured, and they are compared with CO2. This comparison presents that the CO2 flow boiling heat transfer coefficients are higher than R410A …
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Investigation of oil retention and pressure drop in suction lines using R1234yf, R134a and R410A with POE ISO 100
… of lubricant viscosity. Experimental tests in R410A using POE 32 and POE 100 served as data for further comparison. Results show that at similar operating conditions, the more viscous POE 100 yields upto 40 % more oil retention and upto 60 % more pressure drop in comparison to POE 32. It was …
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Design, Testing And Controls For Air Source Heat Pump System In Cold Climates Using Natural & Conventional Refrigerants
… natural refrigerant and conventional refrigerant R410A have been tested and analyzed comparatively to determine the feasibility of air source heat pump systems for space heating applications in northeastern U.S winter climates by replacing the natural gas based heating system as part of the global …
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Design, build-up, and commissioning of R410A chiller facility for experimental investigation into the effect of compressor capacity modulation strategies on seasonal performance
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-05-01
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Potentials for COP increase in vapor compression systems
… expansion valve system operating with R410A. The two major mechanisms of improvement of the ejector system were quantified separately: COP gains between 1.9% to 8.4% were solely due to the work recovery, while liquid-feeding the evaporator alone was responsible for 4.9% to 9.0% of COP …
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Design and Lab Implementation of an Air Source Transcritical CO2 Heat Pump
… was benchmarked using a commercially available R410A heat pump manufactured by LG.</p> <p>The climate chamber maintained steady-state outdoor conditions by combining continuous cooling from the system’s original evaporator coil with resistive heating controlled via feedback loops. Custom …
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Étude des effets d'injections sur le comportement de nouveaux mélanges de réfrigérants en écoulement diphasique
… à base de HFC. Notamment, le R404A, R407C, R410A et le R507. La méthode analysée est la méthode par injections. Plus précisément, par l'injection de liquide, de vapeur chaude et de mélange de liquide et de vapeur chaude. Le comportement en condensation ainsi que celui en ébullition y sont …
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Probabilistic Flow Regime Map Modeling of Two -Phase Flow
… for R134a at 25°C, 35°C, and 50°C, R410A at 25°C, mass fluxes from 100 to 600 kg/m2-s, qualities from 0 to 1 in 8.00 mm, 5.43 mm, 3.90 mm, and 1.74 mm I.D. horizontal, smooth, adiabatic tubes in order to extend probabilistic two-phase flow map modeling to single tubes. An …
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Theoretical and Experimental Analysis of Liquid Flooded Compression in Scroll Compressors
… oil flooding. Further testing on a refrigerant R410A vapor injected compressor with oil injection has shown that the performance with oil injection improves monotonically with the oil injection rate as long as the oil is cooled prior to injection.
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Two-Phase Pressure Drop and Flow Regime of Refrigerants and Refrigerant -Oil Mixtures in Small Channels
… pressure drop data for four refrigerants (R134a, R410A, R290 and R717) were measured in a channel with hydraulic diameter of 148 mum. These data were combined with previous two-phase data of R134a in small channels (hydraulic diameters ranging from 70 to 300 mum) to generate a separated flow model …
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Characterization of Two -Phase Flow in Microchannels
… from 0% to 100% for two-phase flow experiments. R410A, R134a, and air-water mixtures are used as primary fluids. The results from the flow visualization studies indicate that several flow configurations may exist in multi-port microchannel tubes at the same time while constant mass flux and …
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Experimental and numerical investigation of the design and control of vapor-compression systems with integration of two-phase ejectors for performance enhancement through expansion work recovery
… investigation of the two ejector cycles using R410A has been performed; two different microchannel evaporators with the same air-side geometry but different refrigerant-side cross-sectional area are used in the experimental investigation. The experimental results have shown that the more …
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Refrigerant flow distribution in vertical headers of reversible microchannel heat exchangers
… region of R245fa is larger than that of R134a, R410A, and R32, mainly due to its low vapor density and high liquid-to-vapor density ratio. For refrigerant-oil mixture, the distribution is better at high oil circulation rate (OCR) because enough amount of oil generates lots of small …
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Flow pattern mapping of horizontal evaporating refrigerant flow based on capacitive void fraction measurements
… ID smooth tube. Two datasets were gathered using R410A and R134a respectively. A detailed description of the two-phase flow phenomena was presented together wit a sensor signal charaterization using the time signals as well as PDFs and PSDs. All major two-phase flow phenomena were clearly …
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Performance measurement and visualization on the refrigerant distribution in the vertical manifold of the microchannel tube heat exchanger
… new test rig is designed and built to circulate R410A through the vertical microchannel manifold. Refrigerant is circulated into the manifold through the lower set of parallel microchannels and exits through the upper set. Three experimental circular manifolds were developed, each with the …
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Effect of micro-fin geometry on flow and heat transfer during evaporation in round tubes
… tubes and external air-side fins. Experiments of R410A flow boiling inside axial micro-finned tubes and smooth tubes with the inner diameter of 6.3 mm were conducted. The results showed that the average heat transfer enhancement factor of the axial micro-finned tube is 1.34 and the average …
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Flash gas bypass - a way to improve distribution of adiabatic two-phase refrigerant flow in headers of microchannel evaporators
… in vertical impact T-junctions using R134a and R410A as working fluids. Inlet flow rate and quality are varied in the range of 10 - 35 g/s and 10 - 25% with an intention for application in A/C systems with cooling capacities about 1.5 to 6 kW. Flow patterns in the T-junction separator are …
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