Stored Chemical Energy

Inherently safer facilities with respect to chemical reactivity hazards must locus on the magnitude of stored chemical energy, the kinetics of how fast the energy could be released, and the possible reaction products that may themselves have hazardous properties such as toxicity or flammability. 

The thermal efficiency of an energy conversion device is defined as the amount of useful energy produced relative to the change in stored chemical energy (commonly referred to as thermal energy) that is released when a fuel is reacted with an oxidant. 

The electrodes store chemical energy. The amount depends on the thermodynamic quantity of the Gibbs energy of reaction or differences of... 

Respiration refers to those biochemical processes in which organisms oxidize organic matter and extract the stored chemical energy needed for growth and repro-... 

The cell stores chemical energy in the form of energy-rich metabolites. The most important metabolite of this type is adenosine triphosphate (ATP), which drives a large number of energy-dependent reactions via energetic coupling (see p. 16). 

The chemical energy generated by the combustion of energetic materials is converted to thermodynamic energy used for propulsion and explosion. As described in the preceding sections of this chapter, the amount of stored chemical energy is... 

Curve P is quite general and rip represents a realistic maximum conversion efficiency for any device seeking to convert solar energy directly to electricity or stored chemical energy. Boss and Hsiao (3 ) have calculated curves E, Y and P for AM 0 solar radiation. 

A Kinetic Limitation on the Conversion of Light to Stored Chemical Energy... 

Curve P in Fig. 2 represents the ideal thermodynamic limit for conversion efficiency and cuarve C sets an approximate limit for the efficiency of conversion to stored chemical energy. There are, however, other loss factors to be considered which vaary according to the device. These loss factors have been considered in considerable detail for photovoltaic devices (15, 19) and estimates for the ultimate achievable conversion efficiency to electricity vaary from 25 - 2 8% however, only recently have efficiencies been considered for conversion to stored chemical energy (5). In this case... 

The chemical efficiency, Sc, is the fraction of excited state energy converted to stored chemical energy and given by ... 

A battery is an electrochemical cell that stores chemical energy for later use. 

Lipids are primarily hydrocarbon structures (fig. 1.3). They tend to be poorly soluble in water and are therefore particularly well suited to serve as a major component of the various membrane structures found in cells. Lipids also serve as a compact means of storing chemical energy to drive the metabolism of the cell. 

An important parameter to evaluate solarthermal cycles is the solar-to-fuel energy efficiency q, which is defined as the ratio of stored chemical energy and the applied energy according to Equation (7), with CO being the produced fuel [2] ... 

The bacterial photosystem functions without dioxygen production which simplifies the task at hand. Namely, electrons are obtained from more easily oxidized terminal electron donors such as H2S instead of water. Nonetheless, the basic design needed to transform solar energy into stored chemical energy is present. The protein subunits and cofactors that comprise the photosystem in purple bacteria, such as Rhodobacter (Rb.) sphaeroides and Rhodopseudomonas (Rps.) viridis,33 are shown schematically in Fig. 1 which is based on a crystal structure of this assembly.34... 

A fuel cell can be thought of as a cold-combustion power source that generates electrical energy directly from (stored) chemical energy. Due to minimal heat transfers, it is unfettered by conversion-efficiency hmitations characteristic of hot-combustion devices. Unlike batteries, but similar to internal combustion engines, a fuel cell is a continuous-flow system in which fuel and oxidant are externally supplied for operation. In a functional hydrogen-fuel cell, H2 gas is introduced through feed plates to the anode compartment. At the same time, but to the cathode in a separate chamber, O2 gas delivered. At the anode, H2 is oxidized to H ... 

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