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Showing 1 to 20 of 62 for “"R134a"”.
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Flow boiling of R134a in vertical mini-diameter tubes
… pressure drop and flow visualization of R134a in small to mini/micro-diameter tubes. The experimental facility was first designed and constructed by X. Huo (2005) with the contribution of L. Chen (2006). In the present study, the experimental facility was upgraded by changing the heating …
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An experimental facility for microchannel research and evaporating R134a in microchannel tube
… testing results of the facility with evaporating R134a are given. Both heat transfer coefficient and pressure drop are measured and reported in this thesis. The conclusion gives a brief summary of this thesis. The appendix has included calibration data from section 2 and raw data from section 4.
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Heat transfer performance and prediction of low global warming potential R134a refrigerant alternatives
… warming potential (GWP) refrigerants such as R134a. Since many potential alternative refrigerants have flammability and cost concerns, minimizing system charge is critical. The condenser is typically responsible for 50% of the charge of a system; it is vital to have a fundamental understanding …
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Investigation of oil retention and pressure drop in suction lines using R134a with AB ISO 32
… pressure drop in suction lines for a mixture of R134a as refrigerant and AB ISO 32 as the lubricating oil. The oil retention and pressure drop were evaluated in horizontal and vertical suction lines with an internal diameter of 10.2 mm and length approximately 2 m. The system operating conditions …
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Oil retention and pressure drop of R1234yf and R134a with POE ISO 32 in suction lines
… air conditioners as a drop-in replacement for R134a in order to meet European Union’s low GWP requirement. A quantitative comparison of oil retention and pressure drop characteristics of R1234yf and R134a with POE32 oil in 10.2 mm inside diameter horizontal and vertical suction lines at …
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Modeling heat rejection in horizontal smooth round tubes and experimental validation for R1234ze(E), R134a and R32
… and compared to experimental data for R134a, R1234ze(E) and R32 for mass fluxes of 100-300 kgm-2s-1, saturation temperatures of 30 0C - 50 0C and from sub-cooling of 20 0C to superheat of 50 0C in a horizontal smooth tube with 6.1 mm inner diameter. Cavallini et al. (2006) and …
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Investigation of oil retention and pressure drop in suction lines using R1234yf, R134a and R410A with POE ISO 100
… 1-6 m/s. Experiments were also performed in R134a in order to study if R1234yf is a suitable drop-in replacement for R134a. Also, comparisons were made with data obtained using POE ISO 32 to study the effect of lubricant viscosity. Experimental tests in R410A using POE 32 and POE 100 served …
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Experimental and theoretical investigation of novel phase change materials for thermal applications
… properties, behaviour and characteristics of R134a clathrates with additives, as phase change materials (PCMs). PCMs’ charging characteristics are analysed and evaluated for cooling applications. The formation of refrigerant clathrates is investigated due to their potential use in active as …
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Sustainable design of hydrocarbon refrigerants applied to the hermetic compressor
… replaced with hydrofluorocarbons (HFCs) such as R134a which has a zero ozone depletion potential (ODP). The use of HFCs has also come under scrutiny as they have high global warming potential (GWP) and inferior thermodynamic and lubricating properties and have been replaced by hydrocarbon (HC) …
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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 …
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Comparative Life Cycle Assessment of CFC-replacement Compounds in Different Technical Applications
… the presently used 1,1,1,2-tetrafluoroethane (R134a). Additional refrigerants included in this study comprise dichloromethane (R30), propane (R290), isobutane (R600a), carbon dioxide (R744), pentafluorodimethyl ether (E125), 1,1,1’,1’-tetrafluorodimethyl ether (E134), hepta-fluoropropyl methyl …
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Analytical and experimental investigation of two-phase ejector cycles using low-pressure refrigerants
… when compared to expansion valve cycles. R134a and R1234yf were used as the working fluids in the experimental tests. These lowpressure working fluids offer less improvement potential with ejector cycles because of their lower throttling loss, compared to CO2. It was found that two-phase …
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An experimental study of the flow boiling of refrigerant-based nanofluids
… in flow boiling applications, with CO2 and R134a used as the base refrigerants. CuO nanoparticles 40nm in size, and TiO2 nanoparticles 200nm in size are used to create partially stable CO2-based nanofluids. Stable nanofluids are created in R134a by mixing it with dispersions of …
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Cop and capacity improvement through work and heat recovery by using vortex tube
… for different working fluids, including air and R134a. Suitable vortex tube operating conditions have been identified and efficiencies have been calculated from experimental results for both air and R134a. Experimental investigations show that the vortex tube using high pressure saturated R134a …
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Heat transfer and flow characteristics of condensing refrigerants in small-channel cross-flow heat exchangers
… experimentally validate refrigerant inventory of R134a in small-channel cross-flow condensers$\sp\dagger.$ This heat exchanger is used in automotive applications and uses smaller internal volumes than conventional heat exchangers to perform the same task. Since the cost of refrigerants continues …
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Probabilistic Flow Regime Map Modeling of Two -Phase Flow
… flow maps are experimentally developed 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 …
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Distribution of refrigerant and lubricant in automotive air conditioning systems
… is determined with 5% uncertainty in average. R134a and its new environmental friendly alternative R1234yf are used with PAG 46 oil as working fluid at different Oil Circulation Ratio (OCR), ranging from 2% to 4%. Experiments are conducted in two system, one with a fixed Orifice Tube (OT) and …
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Adiabatic Developing Two-Phase Refrigerant Flow in Manifolds of Heat Exchangers
Experiments were performed using R134a in a facility designed for visualization (PDPA, photo) and two-phase flow distribution measurements for various inlet tube and flow characteristics. For most experiments, a transparent manifold in simplified geometry was used. Further experimental analysis is …
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Flow patterns in upward two-phase flow in small diameter tubes
… parameters on flow patterns in small tubes using R134a as the working fluid. The tested tube diameters were 1.10, 2.01, 2.88 and 4.26 mm; the fluid pressures were 6, 10 and 14 bar; the liquid and gas superficial velocities covered a range of 0.04-5.0 m/s and 0.01-10.0 m/s respectively. The …
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Periodic reverse flow in microchannel evaporators
… with different geometries are tested using R134a as the refrigerant. In each evaporator, the reversed vapor flow is vented out of the inlet header and the flow rate is measured. It has been found experimentally that under the same heat flux, superheat and channel length, the microchannel …
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