Abstract: The performances of thermodynamics cycles are dependent on the properties of refrigerants. The performances of Vuilleumier (VM) cycle heat pump adopting mixture refrigerants are analyzed by MATLAB software using REFPROP programming. At given operating parameters and configuration, performances of the VM cycle adopting pure refrigerant, H2, He or N2 are compared. Thermodynamic properti...

introduction pulmonary vein (pv) isolation is considered as a key to atrial fibrillation (af) treatment. cryoballoon ablation is an effective therapy for pv isolation for af with minimal side effects and was approved by the us food and drug administration (fda) several years ago. successful isolation of pvs during cryoablation depends on the balloon temperature and helps in early identification...

Air-to-refrigerant heat exchangers are a key component in all air-conditioning, heat pump and refrigeration systems. The most common of types of air-to-refrigerant heat exchangers are tube-fin and microchannel heat exchangers. There has always been a great emphasis on understating the underlying physics and improving the performance of these heat exchangers. More recently, researchers have been...

Tests were run with both R-12 and R-l34a in a water calorimeter. Refrigerant 12 was run with mineral oil as the lubricant. Evaporating and condensing heat transfer coefficients were calculated over a range of temperatures. To evaluate the impact of the lubricant on the heat transfer coefficients, a oil separator was added. Tests were then run with the oil separator over the same temperature ran...

The world-wide agreement to restrict the use of chlorofluorocarbons (CFCs) and hydrofluorocarbons has prompted recent research exploring the possibilities of replacement refrigerants, particularly those occurring naturally in the environment. One such natural refrigerant, carbon dioxide, has been shown for particular applications to have a COP which is competitive with current refrigerants. How...

Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling fault detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study e...

Having designed the control system, the next stage was to test whether these motion camouflage controllers would be able to fool humans! We did this by performing a novel psychophysical experiment that masqueraded as a computer game competition. The competition was based on a 3D computer game (Missile Defence) of the popular first-person shoot-em-up genre: purpose-written to allow comparison of...

This paper presents environment friendly refrigerant R290 as a solution to the environmental concerns like depletion of ozone layer and rise in global warming because of wide use of synthetic refrigerants R22 and R134a. The water cooler is the widely used refrigeration application in warm climatic countries. Refrigerant R22 and R134a are predominantly used refrigerants in water cooler refrigera...

This project aims to find correlations between various flow parameters and liquid refrigerant flow distribution within a horizontal manifold supplying two-phase R134a downward into fifteen aluminum microchannels. Liquid flow rates, system pressures, and refrigerant temperatures are recorded. Prior to this project, similar experiments were conducted using an identical manifold setup with water/a...