Electrical energy production calculation

Production of electrical energy and remaining electrical energy are calculated by equations (V.69) and (V.70), respectively. 

Variable costs raw material and utilities (electrical energy, steam, cooling water, etc.), overhead (if calculated related to product volume, which is assumed in the example). 

Batteries are everywhere in modern societies. They provide the electric current to start our automobiles and to power a host of products such as pocket calculators, digital watches, heart pacemakers, radios, and tape recorders. A battery is an electrochemical cell, a device for interconverting chemical and electrical energy. A battery takes the energy released by a spontaneous chemical reaction and uses it to produce electricity. 

The magnitude of the energy conversion can be calculated as follows. The amount of electrical energy converted to heat per unit time is given by the product of voltage V and current i. This heat production is spread over the volume of the conducting medium LA, where L is length and A the cross-sectional area of the medium. Thus the rate of heat input H per unit volume is... 

The particular convenience of the path described is that the heat q for step I is zero, while the heat gfor step II can be either measured or calculated. It can be measured directly by carrying out step II (or its inverse) through the addition to the system of a measurable quantity of heat or electrical energy, or it can be calculated from the temperature change (Zj — Zg) resulting from adiabatic step I if the heat capacity of the product system is known. For step I,... 

The direct conversion of sunlight into electrical energy is a viable power source for low-power consumption devices such as this calculator. The cost of photoelectric cells makes them impractical for large-scale power production. 

Activity change indexes were calculated separately for each sector (Table 12.5). Due to the fact that energy production trends are more stable in time and depend on the development of the whole economy, the model set described in Figure 12.1 was used for the electricity and heat production sectors. 

Electrochemical technologists routinely perform energy consumption calculations to understand and improve the economics of electrochemical operations and to compare alternative routes to products of interest. It is usually expressed in AC or DC kilowatt hours (kW hr) per unit weight of the substance produced electrochemically. Note that the electric utility companies charge the customers for the AC kWhr consumed in then-operations. 

Figure 2.11 Comparison of the primary energy usage for ethanol/water separation using traditionai distillation/adsorption process (Fig. 2.9) and hybrid membrane-assisted vapor stripping (MAVS Fig. 2.10) process. Minimum energy (from minimum work calculation) shown as reference. Assumptions 37% and 85% efficient conversion of primary energy to electrical energy and thermal energy, respectively, 0.02 wt% ethanol in stripping column bottoms, and 99.5 wt% ethanol product (0.5 wt% water).

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