Load utilization factor

Load utilization factor Ratio of the effective load in a given space to the load supplied. 

The highest electronic resistances were observed at low Nafion loadings, indicating that the ionomer played a significant role as a binder [211], Meanwhile, kinetic losses pass throngh a minimnm correlated with the electrochemically active snrface area of the catalyst estimated from cyclic voltammograms [209] The higher the electrochemically active surface area, the lower the kinetic losses. This volcano type of cnrve reflects the optimnm in the metal utilization factor u. Below, we try to nnderstand how carbon properties may influence these characteristics. 

Utilities usually pass on to customers the costs of operating low-PF loads. Power factor maybe billed as one, or a combination, of the following ... 

The catalyst layers evaluated in this model-based analysis are not intended to represent the best-in-class in terms of performance. Instead, the experimental studies were picked out from the literature because they provided porosimetry as well as performance data. Nevertheless, the low value of the CL effectiveness factor is a striking result of this analysis. The value of Fcl decreases from 4 % at jo < 0.4 A cm to 1 % aty o 1 A cm . This parameter incorporates statistical effects and transport phenomena across all scales in the CCL. The values found are consistent with an experimental evaluation of effectiveness factors by Lee et al. (2010) if the values found in that study are corrected with the atom utilization factor F p, the agreement is very good. The low value of Fcl suggests that tremendous improvements in fuel cell performance and Pt loading reduction could be achievable through advanced structural design of catalyst layers. 

In order to correlate the electrical dependence with gas flows, the fuel utilization factor is used. This parameter defines the ratio of fuel, which is used in the electrochemical reaction producing electrical current, in relation to the total fuel flow delivered to the cell. It is sufficient to assume that the fuel utilization factor is zero when the fuel eell does not provide power to an external load. Nevertheless, because of the presence of the resistance R2 it is impossible to obtain a zero fuel utilization factor even with completely disconnected from the external circuit (1 3 = 00). To make the model more reliable, the fuel utilization factor is correlated with the current drawn from the ceU by the following equation ... 

The fuel utilization factor of fuel for each stack depends on the load and the number of cells in the stack. In general, in a series connection of stack cells, the current flowing through each cell has the same value. The relationship for computing the fuel utilization of the stack is given by the following equation ... 

The map of performance for the fuel utilization factor is presented in Fig. 5.63. In general, the lower the SOFC-GT load forces, the lower the fuel utilization factor. The highest fuel utilization factor is 0.9 whereas the lowest value is 0.8. This means there is little distance between the maximum and minimum values. 

Engineering factors include (a) contaminant characteristics such as physical and chemical properties - concentration, particulate shape, size distribution, chemical reactivity, corrosivity, abrasiveness, and toxicity (b) gas stream characteristics such as volume flow rate, dust loading, temperature, pressure, humidity, composition, viscosity, density, reactivity, combustibility, corrosivity, and toxicity and (c) design and performance characteristics of the control system such as pressure drop, reliability, dependability, compliance with utility and maintenance requirements, and temperature limitations, as well as size, weight, and fractional efficiency curves for particulates and mass transfer or contaminant destruction capability for gases or vapors. 

The siting of substations, electrical, geographic, economic, political, and aesthetic factors must be considered. The high voltages of the transmission system are utilized because the reduced currents result in more efficient power transmission. Therefore, substations are placed as close to the system loads as possible to minimize losses. This is con-... 

Drilling Applications. Drilling equipment utilizes chain drives in various applications on the drilling rig itself and its auxiliary equipment. The drives for this type of equipment are called compound drives. Such drive equipment are subject to vary severe operational loads. Table 3-24 gives the typical service factors for these chain drives [16]. 

The connection of AA-size cells in parallel can replace larger cells (e.g., D-size cells). Four AA cells fit into a D-size can, and six AA-cells are in equivalent weight to a D-cell [27]. The utilization of the Mn02 cathode is considerably improved because the cathode thickness is only 2 mm in a AA cell, but 5 mm in a D-cell. The internal resistance is also lower by a factor of 4 to 6. Figure 11 depicts a 5 PxlO S bundle battery five AA cells in parallel = 1 bundle, 10 bundles in series make a (nominal) 12 V battery. It is used as the power source for a transmitter/receiver service. A typical load profile is 2 A for 1 min, 0.33 A for 9 min average load, 0.5 A per bundle or 0.1 A per cell service, about 15 h. Smaller bundle batteries (with 2x9 cells) are very suitable for notebook-computers 18 AA cells weight 0.36 kg, and the total initial capacity is 32 Wh. 

Factors affecting the selection of operating conditions are stack size, heat transfer rate, voltage level, load requirement, and cost. The performance curve is defined by cell pressure, temperature, gas composition, and utilization. Typical MCFCs will generally operate in the range of 100 to... 

Connection to the utility grid provides many advantages to on-site power producers such as reliability improvement and increase of load factor, as well as giving the electric utilities a chance to improve the supply capability. When a fuel cell power plant is used for electric utility applications, the inverter is the interface equipment between the fuel cell and the electrical network. The inverter acts as the voltage and frequency adjuster to the final load. The interface conditions require the following characteristics for the inverter ... 

Using a carbon-supported Pt catalyst to replace Pt black can reduce the platinum loading by a factor of 10—from 4 to 0.4 mg/cm [74]. However, the platinum utilization in this PTFE-bound catalyst layer still remains low in the vicinity of 20% [75,76]. 

A factor closely related to the catalyst loading is the efficiency or utilization of the electrode. This tells how much of the electrode is actually being used for electrochemical reaction and can also be seen as a kind of penetration depth. To examine ohmic and mass-transfer effects, sometimes an effectiveness factor, E, is used. This is defined as the actual rate of reaction divided by the rate of reaction without any transport (ionic or reactant) losses. With this introduction of the parameters and equations, the various modeling approaches can be discussed. 

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