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.
Results
Showing 1 to 15 of 15 for “"R1234yf"”.
-
Oil retention and pressure drop of R1234yf and R134a with POE ISO 32 in suction lines
… it has the highest potential for oil retention. R1234yf is a new alternative refrigerant of low global warming potential (GWP) which has been developed for automobile air conditioners as a drop-in replacement for R134a in order to meet European Union’s low GWP requirement. A quantitative …
-
Investigation of oil retention and pressure drop in suction lines using R1234yf, R134a and R410A with POE ISO 100
… and pressure drop in suction lines using R1234yf, the low Global Warming Potential (GWP) refrigerant which was developed as a consequence of the European Union’s Mobile Air-Conditioning Directive. Tests were conducted in 10.2 mm internal diameter horizontal and vertical suction lines that …
-
Analytical and experimental investigation of two-phase ejector cycles using low-pressure refrigerants
… 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 ejectors …
-
Distribution of refrigerant and lubricant in automotive air conditioning systems
… 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 low pressure side accumulator, the other with a …
-
Improvements on performance of a heat pump water heater system
… pattern of water in tank, drop-in refrigerant R1234yf and condenser configuration. This study examines two different models, HPWH-66 and HPWH-50. Simulation is employed and suggestions are made towards a better performance. The performance of HPWH system is found to strongly depend on the …
-
Experimentally validated models of refrigerant distribution in microchannel heat exchangers used to evaluate charge reduction of various working fluids
… different refrigerants including R290, R717, R1234yf, and R134a are used to validate the models. The experimentally validated models are used to compare the charge of various refrigerants. The procedure for charge reduction analysis described in the thesis is the reduction of the internal …
-
Evaporation of pure fluids and mixtures in a microchannel tube
… tube. Six pure fluids (R134a, R32, R1234ze(E), R1234yf, R1233zd(E), and R1336mzz(Z)) are tested, and they have significant difference in properties. The experiments are conducted in a 24-port microchannel tube with an averaged hydraulic diameter of 0.643 mm. The tested microchannel has hydraulic …
-
Potentials for COP increase in vapor compression systems
… subcooling. Numerical results suggested that R1234yf systems would benefit the most from condenser subcooling in comparison to R410A, R134a, and R717. Experimental results obtained with a vehicular air conditioning system revealed COP gains between 6% and 44% for R1234yf and 2% to 21% for …
-
Role of internal heat exchanger in air conditioning systems
… substitution of refrigerants (R134a, R744 and R1234yf among them). It provide extra heat transfer between the high temperature liquid from the condenser and the cold vapor from the evaporator, which can lower the inlet quality to the evaporator and potentially increase system capacity and COP …
-
Commercial Electric Vehicle Cabin Heating System Modelling and Optimization
… Results showed that replacing R134a with R1234yf yields comparable performance with only minor efficiency reductions, while offering substantial environmental benefits. The use of R744 demonstrated strong heating potential but would require a complete system redesign to accommodate …
-
Energy analysis of a collagen production process in Codland's Factory in Iceland
… working fluids are compared for the model and R1234yf was chosen. The maximum power output from the model was 9 kW with 9.8% thermal efficiency. The feasibility study shows that the setup of an ORC is not feasible, mainly due to the low mass flow rate of the steam. Sizing of a heat exchanger …
-
Modeling and design of a power boosted turbo-compression cooling system
… and five working fluids (R134a, R1234ze(E), R1234yf, R245fa, R515a) were evaluated over the range of case study conditions using a fixed heat exchanger effectiveness thermodynamic model. The hybrid thermally and electricity driven "power boosted" TCCS reduced electricity consumption for …
-
Intermediate vapor bypass: A novel design for mobile heat pump at low ambient temperature
… using low pressure refrigerants R134a and R1234yf. Severe heating capacity drop was noticed at extremely low ambient temperature, mainly due to low operating pressure in the outdoor evaporator. Decreasing suction density along with dropping evaporating temperature and suction pressure led …
-
Periodic reverse flow in microchannel evaporators
… are presented. Four refrigerants (R134a, R1234yf, R245fa and R32) are tested in the same system. Heat flux and superheat are maintained the same. It has been found experimentally that R245fa which has similar heat of vaporization with R134a but much larger specific volume difference …
-
Heat transfer performance and prediction of low global warming potential R134a refrigerant alternatives
… R152a, R161, R450A, R452B, R454C, R455A, R513A, R1234yf, R1234ze(E)] and a range of diameters (i.e., 0.5 – 12.7 mm), saturation temperatures (i.e., 15 – 83°C), mass fluxes (i.e., 50 – 1200 kg/m²s), qualities (i.e., 0.007 – 0.999), pressure ratios (i.e., 0.15 – 0.91), Bond numbers (i.e., 0.454 – …