the pressure drop of refrigerant r-134a flow boiling inside a horizontal tube has been investigated experimentally. the test set-up which was used in this investigation is a well instrumented vapor compression refrigeration system. these instruments are thermocouples, flow meter, pressure gauges and the pressure drop measuring apparatus. this system consisted of three electrically heated evapor...

Flow boiling heat transfer with the refrigerants R-134a and R-245fa in copper microchannel cold plate evaporators is investigated. Arrays of microchannels of hydraulic diameter 1.09 mm and 0.54 mm are considered. The aspect ratio of the rectangular cross section of the channels in both test sections is 2.5. The heat transfer coefficient is measured as a function of local thermodynamic vapor qua...

Measurements of two-phase flow pressure drop have been made during a phase-change heat transfer process with refrigerant (R-134a) as a working fluid for a wide range of pressures right up to the critical pressure. The experiments were conducted in a uniformly heated vertical tube of 12.7 mm internal diameter and 3 m length over a heat flux range of 35–80 kW/m, mass flux range of 1200–2000 kg/m ...

Solubility data of refrigerant/lubricant mixtures have been modeled with a cubic equation of state. The systems studied are binary mixtures of hydrofluorocarbons (R-32, R-125, R-134a and R-143a) and alkylbenzene oils (viscosity grades 15 and 32). These partially miscible mixtures are well correlated with the present model, which can be used for calculating the pressure-temperature-composition r...

The phase out of anthropogenic ozone-depleting substances such as chlorofluorocarbons under the terms Montreal Protocol led to development and worldwide use hydrofluorocarbons (HFCs) in refrigeration, air conditioning, blowing agents propellants. Consequently, over recent years, atmospheric abundances HFCs have dramatically increased. are powerful greenhouse gases now controlled 2016 Kigali Ame...

Because of high growth in economy and rapid increase in energy consumption , the government has made efforts to resolve the difficulties of the shortage of energy by restricting the amount of electrical energy consumption for home electrical products and several products consuming energy. Especially, the rules specified how the amount of electrical energy consumption was tested is expected to r...

The objective of this work was to estimate allelic frequencies of the polymorphisms IGF2/MboII (G > T) of the insulin‐like growth factor 2 (IGF2) gene, DQ499531.1:g.134A > T of the pro‐melanin‐concentrating hormone (PMCH) gene, and DQ667048.1:g.3290G > T of the RAR‐related orphan receptor C (RORC) gene in beef cattle of different genetic groups, and to evaluate the associations between these po...