when chemical transport or mechanical work is done by an organism what happens to the heat generated

Chemical Energy

Ech,j is chemical energy of the jth kind of energy carrier used in energy mix.

From: Thermo-ecology , 2019

Biological Resources for Energy

A.M. Paz , in Reference Module in Earth Systems and Environmental Sciences, 2013

Abstruse

The chemical energy stored in biological resource can be converted into useful free energy services such equally oestrus, ability, and transportation fuels. This commodity presents definitions such as energy crop, by-product and waste, and classifies biological materials according to their composition in iv groups: lignocellulosic biomass, sugar and starches, oil biomass, and high-moisture biomass. Common primary and secondary conversion technologies for those groups are as well briefly discussed. Biomass is seen as the renewable energy source with largest potential, merely environmental and socio-economic impacts of bioenergy systems should exist accurately evaluated in social club to guarantee sustainable systems.

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Wind-Based Stand up-Alone Hybrid Energy Systems

Kavadias Kosmas , Triantafyllou Panagiotis , in Reference Module in World Systems and Environmental Sciences, 2021

5.4.ii Chemical energy storage systems

Regarding chemical free energy storage, batteries are considered as the most common and representative technology. They are the most widely adopted storage technique used in many RES-based applications. Unlike battery types be; each one has its own special characteristics, over a wide range of applications. The most mature battery types are the lead-acrid (PbSO _four) and the nickel-cadmium (Ni-Cd) batteries. Atomic number 82-acid batteries are characterized past their considerable self-discharge rate, low maintenance requirements, low energy-density, limited service period, low depth of discharge and considerable environmental impacts. Nickel-cadmium batteries are characterized past their higher energy density and cocky-discharge rate, deep discharge rate, longer service period, high capital cost, low efficiency rates and quite severe environmental impacts. More advanced battery technologies includes sodium-sulfur (Na-S), metal-air and lithium-ion (Li-ion) batteries. For sodium-sulfur batteries, an operating temperature of 300   °C is required, significant that heat supply is necessary. On the other manus, sodium-sulfur batteries have no self-discharge, and efficiency and depth of discharge are quite loftier. Lithium-ion batteries have loftier energy density, a considerable number of accuse-discharge cycles, and deep discharge rates. On the other hand, the primary drawback of the technology is the high capital cost and the required protection circuits to maintain voltage and electric current within prophylactic limits. Finally, metal-air batteries are characterized past loftier energy density, low system performance, short service period, low cocky-discharge rate, and very low system cost.

Catamenia batteries store energy by means of a reversible chemical reaction. The energy is stored in ii liquid electrolyte solutions. The energy capacity and the rated ability of the system are contained of i another. Energy capacity depends on the quantity of electrolytes used. Menstruum batteries are used in a number of big-calibration and stand-solitary RES installations. Different technologies of flow batteries exist (vanadium redox, polysulfide bromine, zinc-bromine) which are characterized past the different electrolytes used. The efficiency of flow batteries ranges between sixty% and 80%, with hereafter prospects ensuring high cycling chapters and deep belch rates. Finally, the significant environmental impacts should besides exist considered as a drawback of the technology.

Product of hydrogen is i of the ideal methods for the absorption of intermittent/stochastic RES such equally wind energy. In FC-HS systems, the renewable energy is converted to fuel (hydrogen), which is stored in advisable storage tanks. The storage capacity depends only on the corporeality of the hydrogen that demand to exist stored and is theoretically independent of the fuel cell's nominal power. During the discharging process, hydrogen is released from the storage tank and is fed to the fuel cell unit, which then generates electricity. The main drawback of the FC-HS systems is the low accuse-discharge cycle efficiency estimated to exist between 30% and 40%, including the losses during both the electrolysis to produce hydrogen and the storage stage. The advantages of the engineering science, on the other paw, include the low energy cost, the high energy density, and the negligible cocky-discharge rate.

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Principal Production: The Foundation of Ecosystems

Michael L. Pace , ... R. Quinn Thomas , in Fundamentals of Ecosystem Science (Second Edition), 2021

Chemosynthesis exploits chemic energy to convert inorganic carbon compounds into organic thing, in dissimilarity with photosynthesis, which exploits the energy of low-cal to produce organic matter. Prokaryotic microorganisms, principally bacteria and archaea (referred to equally "bacteria" in the following), carry out chemosynthetic reactions. Energy is produced in chemosynthetic reactions from oxidizing reduced compounds. At that place are a variety of chemosynthetic bacteria that behave out these reactions, including nitrifying bacteria (oxidizing NH ₄ or NO_two), sulfur bacteria (oxidizing H₂S, S, and other sulfur compounds), hydrogen leaner (oxidizing H_two), methane bacteria (oxidizing CH_iv), atomic number 26 and manganese leaner (oxidizing reduced iron and manganese compounds), and carbon monoxide leaner (oxidizing CO). This is not an exhaustive list, and new modes of chemosynthesis too every bit new chemosynthetic leaner are all the same being discovered.

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APPLICATIONS – STATIONARY | Residential Energy Supply: Fuel Cells

L. Jörissen , in Encyclopedia of Electrochemical Power Sources, 2009

Fuel cells convert chemical energy efficiently into electricity. Due to inevitable losses, a part of the energy is generated in the class of heat. Fuel cell systems thus can be used for the combined generation of heat and ability even on small scale in individual buildings. Combined rut and power generation (CHP) allows a more efficient utilise of fuel than the traditional way of generating, for exampe, electricity in centralized power plants or estrus in individual boilers. This commodity introduces the concepts used in fuel cell systems for CHP. Furthermore, opportunities and challenges to market introduction are presented.

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Redox Chemical science

William F. Bleam , in Soil and Environmental Chemistry, 2012

8.four.one Catabolism and Respiration

The release of chemical free energy stored in organic compounds occurs in two stages: catabolism and respiration. Reduction leading to carbon dioxide release occurs during catabolism: the electron donor is the organic compound being catabolized, while the electron acceptor is the oxidized form of nicotinamide adenine dinucleotide NAD ⁺ (CAS 53-84-nine, Structure 3) or a similar compound (eastward.g., flavin adenine dinucleotide FAD or nicotinamide adenine dinucleotide phosphate NADP ⁺).

Structure 3. NAD ⁺

Structure four. NADH

(eight.63) $NA{D}^{+}+H^{+}+\mathrm{two}\cdot {\mathrm{east}}^{-}\to NADH$

Catabolism reduces NAD⁺ to NADH (CAS 606-68-8, Structure four) in reduction half reaction (viii.63). For example, glucose catabolism involves three processes: glycolysis, pyruvate oxidation, and the tricarboxylic acid cycle. Reduction one-half reaction (8.64) represents glucose catabolism past this pathway.

(8.64) $\mathrm{half\; dozen}\cdot C{O}_2+24\cdot H^{+}+24\cdot e^{-}\to \underset{glucose}{C_6{H}_{12}{O}_6}+6\cdot H_{2}O$

Combining reduction half reactions (8.63) and (8.64) illustrates glucose dissimilation to carbon dioxide (8.65). Notice that the electron acceptor is NAD⁺ (viii.63), not O ₂: the electron ship chain, and not the catabolic pathway, defines the terminal electron acceptor.

(8.65) $\underset{glucose}{C_{\mathrm{six}}{H}_{12}{O}_6}+12\cdot \underset{\begin{array}{c}\text{nicotinamide}\\ \text{adenine}\\ \text{dinucleotide}\end{array}}{NA{D}^{+}}+6\cdot H_{2}O\to \mathrm{six}\cdot C{O}_2+12\cdot \mathrm{Due\; north}ADH+12\cdot H^{+}$

Reduced nicotinamide adenine dinucleotide NADH functions every bit a redox cofactor. Reduced NADH is an electron carrier, shuttling electrons from various catabolic pathways to the electron transport chain, and functions as the electron donor feeding electrons into the electron transport concatenation.

While all organisms utilize numerous catabolic pathways, bacteria accept evolved a broader array of catabolic pathways than other organisms, making them important players in the environmental degradation of organic contaminants. Bacteria also draw upon a more flexible electron transport chain, providing them with respiratory alternatives absent in eukaryotes. Many bacteria go on to respire in the absenteeism of O _two—a process called anaerobic respiration—by utilizing a multifariousness of terminal electron acceptors every bit the need arises.

Anaerobiosis eliminates the activation barrier impeding the abiotic oxidation of nitrate and sulfate through the specialized electron transport chains of nitrate- and sulfate-reducing leaner. While platinum ORP electrodes may have express sensitivity to these redox couples, some of the reduction products (ferrous iron, thiosulfate, etc.) are sufficiently electroactive and soluble to yield measureable platinum ORP electrode voltage displacements.

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Biological free energy transformations by plants

David E. Reichle , in The Global Carbon Bicycle and Climate Change, 2020

Abstruse

The major source of chemical free energy for living systems is derived from the oxidation of organic, carbon-based compounds. The main method of product of these organic compounds is the utilization of radiant energy by chlorophyll-bearing dark-green plants to synthesize glucose from carbon dioxide and water. There are many strategies used past plants (C3, C4, and CAM) to either minimize or increment the assimilation of the incident radiation flux. Photosynthetic efficiency is typically between i% and 2%. Free energy-rich molecules are formed past the oxidation of photosynthetic substrates which are liberated from these molecules by hydrolysis. Thus, radiant energy is converted to chemical energy through metabolic processes to perform work past the organism.

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Distributed Energy, Overview

Neil Strachan , in Encyclopedia of Free energy, 2004

5.4 Fuel Cells

Fuel cells catechumen chemic energy directly into electrochemical work without going through an intermediate thermal conversion. Thus, the second law of thermodynamics does not apply, they are non limited by Carnot's theorem, and, therefore, they offer the potential of very high electrical efficiencies. In a fuel cell, the fuel (H _two) and the oxidizer (O₂) are supplied continuously (unlike in a battery). A dynamic equilibrium is maintained, with the hydrogen being oxidized to water with electrons going around an external wire to provide useful electric work. A major limitation of fuel cells is that direct efficient oxidation of natural gas (CH₄) is not still possible. Therefore, a reformer is used to catechumen CH₄ to H₂, with resulting losses in overall efficiency and creation of CO₂ as a by-product.

There are four principal types of fuel cells in development. Fuel cells can either use additional heat for the reformer or their own waste matter heat. They are compared in Table III.

Table III. Categorization of Major Fuel Prison cell Types

Type	Operating temperature	Reforming	Efficiency (HHV)	Comments
Phosphoric acid (PAFC)	200°C	External heat required	33–40%	Commercialized
Proton-commutation membrane (PEMFC)	80–100°C	External oestrus required	33–forty%	Poisoned by traces of CO
Molten carbonate (MCFC)	600–650°C	Internal heat	48–55%	Internal reforming can crusade variable H2
Solid oxide (SOFC)	900–yard°C	Internal heat	42–58%	Current R&D favorite

Fuel cells accept many admirable qualities for ability production including a high potential efficiency, no loss in functioning when operating at partial load, ultralow emissions, and tranquility operation. Their high uppercase costs are a major barrier to development.

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Examples of awarding of TEC

Wojciech Stanek , ... Tomasz Simla , in Thermo-ecology, 2019

Combined heat-and-power plant

Total consumption of chemical energy of fuel in a CHP constitute:

(iii.9) ${\dot{E}}_{F,CHP}=\frac{{\dot{Q}}_{CHP}+N_{CHP}}{{\eta }_{E,CHP}}$

where ${\dot{Q}}_{CHP}$ is rut produced in CHP, kW; ${\mathrm{North}}_{CHP}$ is electric power of CHP, kW; ${\eta }_{E,CHP}$ is energetic efficiency of CHP.

Exergy cost burdening the exergy of products generated in the CHP plant:

(3.x) $k^{\ast }=\frac{\alpha {\dot{\mathrm{Due\; east}}}_{F,CHP}}{{\dot{Q}}_{CHP}\frac{T_{\mathrm{yard}}-T_0}{T_{\mathrm{one\; thousand}}}+N_{CHP}}$

where α is ratio of chemic exergy of fuel per unit of lower heating value (b _ch,F /LHV).

The expression in the numerator of Eq. (3.10) denotes the total exergy of fuel feeding the CHP organisation, whereas the expression in the denominator denotes the total exergy of useful products of the CHP system. Two useful products are generated in CHP; for this reason the distribution of the environmental burden on heat and electricity is determined by identifying the primary product showtime, and then the rest of the ecology burden is designated to the by-product.

Consumption of chemic free energy of fuel burdening the fabrication of useful rut in the CHP:

(3.xi) ${\dot{E}}_{F,Q}={\dot{Q}}_{CHP}\frac{T_{\mathrm{one\; thousand}}-T_0}{T_m}\frac{{\mathrm{thousand}}^{\ast }}{\alpha }$

TEC burdening heat produced in the CHP:

(three.12) ${\rho }_Q=\frac{E_{F,Q}}{LH\mathrm{Five}}\left({\rho }_{hc}+{\rho }_e\right)$

TEC burdening electricity produced in the CHP:

(3.thirteen) ${\rho }_{el}=\frac{E_{F,CHP}-{\mathrm{East}}_{F,Q}}{LHV}\left({\rho }_{hc}+{\rho }_{\mathrm{due\; east}}\right)$

Within TEC methodology, CHP is more complicated to evaluate than PP or HP, since two products are fabricated using 1 technology.

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SECONDARY BATTERIES – LITHIUM RECHARGEABLE SYSTEMS – LITHIUM-ION | Positive Electrode: Layered Metal Oxides

J.B. Goodenough , in Encyclopedia of Electrochemical Power Sources, 2009

Secondary Batteries

A battery stores chemical energy in the electrode of an electrochemical cell or an assembly of such cells and delivers, on discharge, electric ability to an electric or electronic device. The chemical reaction in a battery involves both electron and ionic flow from one electrode to the other of an electrochemical cell; the cell directs the electron flow through an external circuit and sustains the ionic flow inside the battery. The cells of a battery associates are continued to one another so equally to evangelize an electronic current I at a voltage V to give a specified ability P=IV in the external circuit; the electronic current I is matched past the ionic current I _i flowing inside the battery to complete the chemic reaction between the electrodes. Because the electronic electrical conductivity is much greater than the ionic conductivity, matching the currents I and I _i requires electrodes of a big surface area that are separated by a sparse electrolyte. The mobile ion inside the battery is called the working ion. A secondary battery is reversible; information technology transforms electric free energy back into chemic energy stored in the electrodes of the cells on charging the battery. The primal component of a battery is the electrochemical jail cell.

Every bit illustrated schematically in Figure 1, an electrochemical cell consists of a positive and a negative electrode separated by an electrolyte that conducts the working ion but is an electronic insulator. Each electrode is connected to a electric current collector that concentrates the electron catamenia into a positive and a negative post for contact to the external excursion. If the electrolyte is a liquid, a separator must be added to keep the electrodes apart; the separator is an inert material permeable to the liquid electrolyte. If the electrolyte is a solid, it also acts equally the separator.

Figure ane. Schematic of components of a jail cell with current flows during discharge.

Conventional secondary (rechargeable) batteries apply either a strongly acidic or a strongly alkaline aqueous electrolyte in which the hydrogen ion (H⁺) is the working ion. In the lead–acrid bombardment PbO_ii/H_iiSO₄/Atomic number 82, for example, lead oxide (PbO₂) is the positive electrode (the cathode), elemental lead is the negative electrode (the anode), and the electrolyte is sulfuric acid as described in SECONDARY BATTERIES – LEAD–Acrid SYSTEMS: Overview. On the reverse, both the nickel–cadmium NiOOH/KOH/Cd and nickel–metal hydride NiOOH/KOH/MH _y element of group i batteries use nickel oxyhydroxide as the cathode and potassium hydroxide as the electrolyte. The cadmium anode reacts with the water of the electrolyte to grade a cadmium hydroxide gel at the anode, which displaces mobile H⁺ ions to the cathode:

[I] ${\text{Cd}+2\text{H}}_2\text{O}\rightleftarrows {\text{Cd}(\text{OH})}_2+2{\text{H}}^{+}+\mathrm{ii}{\text{due east}}^{-}$

A metal hydride, MH _y , anode releases H⁺ ions direct from the hydride in the reaction

[2] ${\text{MH}}_y\rightleftarrows {\text{MH}}_{y-\mathrm{ten}}+\mathrm{ten}{\text{H}}^{+}+x{\text{e}}^{-}$

At the cathode, the H⁺ ions are inserted into the nickel oxyhydroxide (NiOOH) in the reaction

[III] $\mathrm{ten}{\text{H}}^{+}+\mathrm{10}{\text{e}}^{-}+\text{NiOOH}\rightleftarrows {\text{NiO}}_{\mathrm{one}-x}{(\text{OH})}_{\mathrm{one}+x}$

All these reactions are reversible in these secondary batteries.

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Fossil Fuel Power Stations—Coal Utilization

L.Douglas Smoot , Larry 50. Baxter , in Encyclopedia of Concrete Science and Technology (3rd Edition), 2003

II.C Fuel Considerations

A boiler converts chemic energy stored in fuels into steam that is used to produce electricity or for process use. The theoretical and practical limitations of this procedure determine the ultimate engineering science and systems making up the overall power plant. Carbon, hydrogen and oxygen are responsible for the majority of the calorific value of the fuel.

A convenient analogy of the relationships between many fuels is based on the carbon, hydrogen, and oxygen content and is referred to equally a coalification diagram when restricted to coal (Fig. 3). Natural gas has a hydrogen-to-carbon ratio of about 3.6 and an oxygen-to-carbon ratio of near 0, but is not conveniently illustrated at the scale of this diagram. As is seen, major solid fuels fall into consistent regions of the diagram.

Effigy iii. Coalification diagram indicating the relationships among a variety of solid fuels in terms of their chemical composition.

The remaining fuel components are typically nitrogen, sulfur, and inorganic impurities. It is ultimately the impurities in the fuel and process materials that drive engineering decisions regarding ability station technologies and operating weather condition. The contributions most directly associated with carbon, hydrogen, and oxygen such as acme flame temperature have less influence on performance than idealized theoretical analyses might advise. Fuel impurities and limitations of electric current materials place the greatest restrictions on banality pattern and operation. With low-class fuels these restrictions tin be substantial.

Coal is commonly classified by rank, with the major classifications beingness, in order of decreasing rank, anthracite, bituminous coal, subbituminous coal, and lignite. The information inFig. three illustrate how fuel backdrop vary with rank and how they chronicle to each other. Coals nigh commonly used for steam generation have molecular hydrogen-to-carbon ratios ranging from 0.7 to 0.ix and molecular oxygen-to-carbon ratios ranging from virtually 0 to almost 0.2.

While coal rank correlates with oxygen and hydrogen content, coal rank is determined principally past heating value except for the highest rank dress-down and anthracites, which are distinguished on the basis of stock-still carbon contents (according to ASTM standards). Heating value is the amount of energy released from a fuel during combustion and is discussed later in this commodity.

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