Electrical-watt density

When specified, a removable steam heating element external to the oil reservoir or a thermostatically controlled electric immersion heater with a sheath of austenitic stainless steel shall be provided for heating the charge capacity of oil before start-up in cold weather. The heating device shall have sufficient capacity to heat the oil in the reservoir from the specified minimum site ambient temperature to the manufacturer s required start-up temperature within 12 hours. If an electric immersion heater is used, the watt density shall not exceed 2.33 watts per sq. cm (15 watts per sq. in.). 

The luminous efficiency is the simplest to calculate. It is the ratio of the luminance (cd/m2) to the current density (A/m2), and has units of cd/A. Finally, the power efficiency is the ratio of the light output in lumens divided by the electrical input in watts. For reference, a typical incandescent light bulb is 151m/W, while a fluorescent light bulb is 601m/W. 

He/Ne laser focussed into a small tapered hole in a pellet of the plastic. The flux density achieved at the focus was about 1000 Watts/cma. The scattered radiation was examined using a double spectrometer and photon-counting detection. A very fine spectrum, superior even to that of Maklakov and Nikitin (see Table 1), was recorded photo-electrically. Schaufele pointed out that a band atAv= 109cm-1 forecast previously by Tadokoro et aL (15) was not observed at first but in a note added in proof he mentions that a feature may be genuine at 98 2 cm-1. A band had already been observed at Av= 110cm-1 by instrument developers at the Cary Instrument Co. since Szymanski (16) shows a spectrum of isotactic polypropylene, recorded at Monrovia, Calif., on a laser sourced Cary 81 spectrometer, as an example of recent advances in Raman spectroscopy. 

The capacity of a collector is expressed in terms of its peak power production (Wp). This is the amount of electric power that a PV module is able to generate when it receives 1,000 watts per square meter of vertical solar irradiation at 25°C cell temperature. This is also called one sun. If this level of insolation existed for 24 h every day of the year, each m2 of collector area would receive 8,760 kWh/yr. The actual rate of power generation is naturally less. The value of Wp/ m2 of a module is also called its power density or efficiency. Therefore a 10% efficient module when receiving one sun will generate 0.1 kWp/m2 and a 15% will generate 0.15 kWp/m2. 

The Helmholtz capacity always depends strongly on the charge density au, different metals may have quite different capacities, but typically there is a maximum, also known as the hump, near the pzc (see Fig. 2). Since the strength of the electric field increases on both sides of the pzc, the occurrence of the hump can he explained by dielectric saturation. Watts-Tobin [6] elaborated this idea into... 

Based on the above minimum active fluid volume, it is also possible to estimate the electric power required to power the electromagnet. For MR fluid that is operating near its maximum yield strength, the magnetic held energy density that needs to be established in the fluid is approximately 0.1 J/cm . Thus, in order to establish the required magnetic field H within a desired time interval At, the power source must be capable of supplying a minimum electric power Pei (in watts) that equals 0.1 J/cm times the fluid volume fmin (in cm ) divided by the time interval At (in seconds) ... 

The wattage of an appliance indicafes the average power consumption in watts (W), where IW = IJ/s. What is the difference in the number of kJ of energy consumed per month between a refrigeration unit that consumes 625 W and one that consumes 855 W If electricity costs 0.15 per kWh, what is tire monthly cost difference to operate the two refrigerators (Assume 30.0 days in one month and 24.0 hours per day.) 108. A portable electric water heater transfers 255 watts (W) of power to 5.5 L of water, where IW = IJ/s. How much time (in minutes) will it take for the water heater to heat the 5.5 L of water from 25 °C to 42 °C (Assume that the water has a density of 1.0 g/mL.)... 

From Fig. 20.2 it can be seen that there is a linear increase of the produced electric power with increasing active cell area under the assumption that scaling up of the active area does not influence the cell behavior. For a current density of 450 mA cm at reformate operation the produced electric power increases from 2.35 W at 10 cm active cell area to 235 W at 1000 cm. For the designated applications in the power range of some hiuidred watts or even... 

Energy density. The amount of the electrical energy a battery stores per unit volume at a specific discharge rate. This is also known as volumetric energy density and is expressed in watt-hour per liter. 

Power density. The amount of power a battery can deliver per unit volume at a specified state of charge, which is typically is 20%. This quantity is also known as volumetric power density and is expressed in watts per liter. Specific energy. The amount of electrical energy a battery is able to store per unit mass at a specified state of charge. This is also known as the gravimetric energy density and is expressed in watt-hour per kilogram. 

The polarization curve represents the fuel cell output voltage as a function of the current density in steady state. Electrical power, in watts, supplied by the fuel cell to the load, can be determined using the following equation ... 

Besides being environmentally friendher than Nicad batteries, nickel-metal hydride batteries have a higher energy content per unit mass. This is called the battery s energy density with units expressed in watt-hour/kg. These batteries are commonly used in hybrid electric cars and buses. 

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