BACKGROUND Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with ...

The aim of the present paper is to examine the effect of ambient temperature on the performance of a combined cycle power plant. For this work, the combined cycle plant chosen is NTPC (National Thermal Power Corporation) Dadri, India where a gas unit of 817 MW is installed. The effect of ambient temperature on combined cycle efficiency, gas turbine cycle efficiency, exergy destruction in differ...

Air pre-cooling equipment is normally being employed in air-conditioning systems for pre-cooling the ambient outdoor air to enhance the air-conditioning systems performance. In this study, the potential of a passive water-to-air heat pipe based heat exchanger (HPHEX) for air pre-cooling purpose in air-conditioning systems for the high cooling load demanding regions of Iran was investigated. To ...

Radial flow reactor was focused for large scale methanol synthesis and in which the heat transfer type was cross-flow. The effects of operating conditions including the reactor inlet air temperature, the heating pipe temperature and the air flow rate on the cross-flow heat transfer was investigated and the results showed that the temperature profile of the area in front of the heating pipe was ...

This paper presents a mixed-integer nonlinear programming (MINLP) model for the optimal design of mechanical counter-flow cooling towers, subjected to standard design constraints. The objective function consists of the minimization of the total annual cost, which includes the capital cost of the cooling tower (that depends on the filling material and the air flowrate) and the operating cost (th...

We designed a simple and efficient inlet system to act as an interface between samples at atmospheric pressure and the high vacuum inside a mass spectrometer. The newly designed stainless steel orifice leak sample inlet system is simple and rugged and fulfills all the basic requirements. With this inlet system coupled with a lithium ion attachment mass spectrometer, it is possible to detect any...

In this paper a gas turbine power plant including air preheater (recuperator), heat recovery steam generator and air cooler system was modeled. Eight parameters were selected as the design variables.  Fast and elitist non-dominated sorting genetic algorithm (NSGA-II) was applied (to maximize the exergy efficiency and to minimize the total cost rate) for the mentioned cogeneration system. Th...

Inefficient use of raw materials in most catalytic processes can be attributed mainly to the deactivation of the catalyst in chemical reactors. In order to achieve efficient use of raw materials, this paper addresses mitigation of deactivation through optimization of inlet temperature-time trajectories. The optimization of temperature profiles in reactors is one of the key problems in the synth...

Hydrogen has been known as a clean and suitable fuel to replace conventional fossil fuels. One of the common hydrogen production methods is using water electrolysis process. This method produces oxygen as well as hydrogen by ratio of 1:2. The aim of this work is to investigate the effects of inlet air enrichment by adding produced hydrogen and oxygen to an internal combustion engine. For this p...