In Japan, the refrigerant used in room air-conditioners has been changed from HCFC-22 (R-22) to R-410A, a blend of HFC-32 and HFC-125 (50/50 vt%), in order to protect the ozone layer. Generally, the miscibility between the refrigerant and refrigeration oil must be assured, because the oil needs to return to the compressor from the refrigeration cycle and lubricate the sliding parts. Alternative...

The HAMP domain is a linker region in prokaryotic sensor proteins and relays input signals to the transmitter domain and vice versa. Functional as a dimer, the structure of HAMP shows a parallel coiled-coil motif comprising four helices. To date, it is unclear how HAMP can relay signals from one domain to another, although several models exist. In this work, we use molecular simulation to test ...

The VIPTM compressor is a new, high-quality product line from the Dresser-Rand company. It incorporates a valve-in-piston cylinder. This is a unique design which results in higher efficiency and fewer parts. The VIP cylinder design is drastically different from the conventional reciprocating compressor cylinders in that the valve are an integral part of the piston assembly. Finite element analy...

Energy savings by reducing the thermal and mechanical losses in machines is of major concern due to continuous depletion of energy resources. Frictional losses of engine components cause energy losses leading to high fuel consumption. In piston assembly, piston skirt and liner interaction contribute as much as a frictional loss as the piston rings but more studies have been focused on piston ri...

We used a capacitive technique to determine the radial clearance between the piston and cylinder of a gas piston gauge. This method determines the effective area of a piston gauge pressure standard, independent of calibration against another piston gauge or manometer, as long as the diameter of the piston is dimensionally measured. It also allows an independent determination of piston gauge dis...

A liquid piston concept is proposed to improve the efficiency of gas compression and expansion. Because a liquid can conform to an irregular chamber volume, the surface area to volume ratio in the gas chamber can be maximized using a liquid piston. This creates near-isothermal operation, which minimizes energy lost to heat generation. A liquid piston eliminates gas leakage and replaces sliding ...

We present a novel design of a single-cylinder free piston engine linear generator (FPELG) incorporating a linear motor as a rebound device. A systematic simulation model of this FPELG system was built containing a kinematic and dynamic model of the piston and mover, a magneto-electric model of the linear generator, a thermodynamic model of the single-cylinder engine, and a friction model betwe...

We consider a heavy piston in an infinite cylinder surrounded by ideal gases on both sides. The piston moves under elastic collisions with gas atoms. We assume here that the gases always exert equal pressures on the piston, hence the piston remains at the so called mechanical equilibrium. However, the temperatures and densities of the gases may differ across the piston. In that case some earlie...