Parasitic losses

Figure Bl.28.8. Equivalent circuit for a tliree-electrode electrochemical cell. WE, CE and RE represent the working, counter and reference electrodes is the solution resistance, the uncompensated resistance, R the charge-transfer resistance, R the resistance of the reference electrode, the double-layer capacitance and the parasitic loss to tire ground.

Fan Rating. Axial fans have the capabiUty to do work, ie, static pressure capabiUty, based on their diameter, tip speed, number of blades, and width of blades. A typical fan used in the petrochemical industry has four blades, operates neat 61 m/s tip speed, and can operate against 248.8 Pa (1 in. H2O). A typical performance curve is shown in Figure 11 where both total pressure and velocity pressure are shown, but not static pressure. However, total pressure minus velocity pressure equals static pressure. Velocity pressure is the work done just to collect the air in front of the fan inlet and propel it into the fan throat. No useflil work is done but work is expended. This is called a parasitic loss and must be accounted for when determining power requirements. Some manufacturers fan curves only show pressure capabiUty in terms of static pressure vs flow rate, ignoring the velocity pressure requirement. This can lead to grossly underestimating power requirements. 

The parasitic loss caused by the leakage inductance can be harnessed as seen later. 

Identifying and harnessing these parasitic losses into the operation of the QR power supply is an interesting challenge that should be undertaken. So, carefully analyze its operation and play with the arrangement of the tank circuits. 

When parasitic losses are measured as a fraction of the power developed in the cylinder or cylinders, that fraction can be improved in two ways. Either the parasitic losses themselves can be reduced, or the power developed in the cylinder or cyinders can be increased. Over the years, both paths have been pursued. 

These changes have raised the air capacity of the engine, resulting in increased power deliveiy for a given displacement. If the engine displacement is then decreased to hold maximum power constant, the parasitic losses are smaller for the same output power capability. This can be translated into improved vehicle fuel economy. 

The complete system with fuel cell is under development. Its projected cost will be 400—500 (U.S. dollars) for a 130 Wg output. The system efficiency is estimated to be 9%. This efficiency includes parasitic losses and an assumed fuel cell efficiency of 50%. The parasitic power requirements by the BOP components are about 70 Wg, mostly from the eight magnetic valves, which is one cause for the low system efficiency. The researchers are looking for lower-power magnetic valves and other solutions to decrease the parasitic power requirements. 

In order to better understand the above values for FCS efficiency, the main parasitic losses are shown in Fig. 6.7, where each curve is representative of the electric power absorbed by each auxiliary component of the FCS, and is reported as a function of the DC-DC converter power. The major consumption is due to the... 

The results shown in previous sections suggest the crucial role of the oxidant supply system, in particular the effect of the stoichiometric ratio (air flow rate) on FCS efficiency and dynamic performance. In order to give further information about this issue, in this paragraph different air management strategies are closely examined, with particular reference to their influence on cell voltage uniformity and air compressor parasitic losses. 

Finally, an efficiency r/par (which is less than one) due to parasitic losses composed of selfabsorption16, 17) of the fluorescence by the emitting centers, absorption and scattering by chemical and structural imperfections. As discussed below, a special case is absorption due to a quasi-stationary concentration of excited states (such as triplet states of organic dye-stuffs) maintained by the illumination. 

The thermal integration of the system has a significant impact on the fuel conversion efficiency of the hydrogen production system. An optimal process configuration that generates the process steam with minimum parasitic losses was selected, and the fuel conversion efficiency on an LHV basis was estimated to be 75.2%. Compressor calculations showed that electricity required was around 1% of the LHV of the fuel. 

In order to reduce the material costs of fuel cells to meet automotive cost targets, it is necessary to lower the total amount of precious metals in the system [3]. There are several ways to reduce the amount of platinum required to deliver a unit of net power from a fuel cell power plant (1) reducing parasitic losses at the power plant level, (2) increasing the... 

Different DMFC system may have different parasitic losses and configurations. The present results are obtained by simulations in comparison to an actual DMFC system [69] that is recognized as an optimized DMFC system. 

Fig. 11.10 - Equivalent circuit for an electrochemical cell. is the resistance of the reference electrode, and Qef represents parasitic loss to ground in the leads. Rs and are the solution and uncompensated resistances respectively, Cji the double layer capacitance of the working electrode, and / ct the charge transfer resistance.

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