Effect of standby mode operation of some household appliances on disturbance voltage and current in frequency range of 9–150 kHz produced by other equipment in low voltage network
Most household appliances commercially available today on the market are equipped with the inverter technology favoring to its smaller size, advanced performance, and energy efficient. Notwithstanding its benefits, unfortunately, this technology may introduce current disturbance according to its relevant frequency switching and eventually degrades power quality. The switching frequency of inverter for household appliances is generally in the range of 9-150 kHz causing the disturbance and may influence the working performance of other appliances. The voltage and current disturbances in the frequency range of 9-150 kHz are not completely covered and currently subject to standardization work. Some household appliances can be operated in standby mode in order to display the time and setting information or to allow them to operate quickly even though it also gives a drawback regarding to its energy consumed. This study investigates the characteristics of standby mode operation of some appliances and its effect to the voltage and current disturbance in the frequency range of 9-150 kHz. The result shows that the standby mode operation of particular household appliances can filter and significantly reduce the voltage and current disturbance in the low voltage (LV) installation network for specific frequency in the range of 9-150 kHz.
Research on energy-saving control of standby household appliances
With the increase of the types and numbers of the household appliances, electrical appliances' standby energy consumption has attracted more and more people's concern. To reduce the energy waste of the household appliances, a method for the energy-saving control of the standby household appliances is presented in this paper. The presented method divides the indoor electrical circuits into two parts, one of which is the circuit that can be powered down while the other can not be turned off. An algorithm that fuses the detected current information and the pyroelectric infrared sensor information is put forward to assure that the circuit will be cut off when the household appliances in the circuit that can be powered down are at the standby states and nobody is at home. Also, the software and hardware design schemes are given in detail, and the energy-saving control devices for the standby appliances are developed. At last, experiments are made. From the experimental results, we can observe that the developed system is reliable and has great importance on energy conservation.
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.