Energy conservation: heat pumps

FIGURE 19-30 Heat generation by uncoupled mitochondria. The uncoupling protein (thermogenin) of brown fat mitochondria, by providing an alternative route for protons to reenter the mitochondrial matrix, causes the energy conserved by proton pumping to be dissipated as heat. 

Heat pump - [HEAT-EXCHANGE TECHNOLOGY - NETWORK SYNTHESIS] (Vol 12) -role m process energy conservation [PROCESS ENERGY CONSERVATION] (Vol 20)... 

When we consider that we lose work potential in chemical reactors, in heat exchangers, and in mixing operations and combine this with the need for work in separation processes, pumping, and compression, it becomes dear that chemical processes are usually very inefficient from an energy standpoint. Of course, energy conservation is usually of secondary importance in chemical processing safety, quality, and productivity are more important, Nevertheless, it is economically sound... 

Geeraert B. Air drying by heat pumps with special reference to timber drying Heat Pumps and Their Contribution to Energy Conservation. NATO Advanced Study Institute, Series E Applied Sciences 15 219-246, 1975. 

In recent years considerable emphasis has been placed on energy conservation and environmental pollution control. As discussed earlier, the former problem is likely to be solved, at least in part, by the introduction or wider use of more efficient fuels such as biomass or nuclear fuel, coupled with more controlled application of what is at present waste heat from chemical reactions. This is now more than ever possible because of the improved and improving design of heat pumps, boilers, heat exchangers, etc., the use of which is more nearly optimized by computer control. Emissions of gaseous pollutants have been decreasing in recent years by improved methods of condensation, adsorption. 

Of a more complete approach are the zone models [3], which consider two (or more) distinct horizontal layers filling the compartment, each of which is assumed to be spatially uniform in temperature, pressure, and species concentrations, as determined by simplified transient conservation equations for mass, species, and energy. The hot gases tend to form an upper layer and the ambient air stays in the lower layers. A fire in the enclosure is treated as a pump of mass and energy from the lower layer to the upper layer. As energy and mass are pumped into the upper layer, its volume increases, causing the interface between the layers to move toward the floor. Mass transfer between the compartments can also occur by means of vents such as doorways and windows. Heat transfer in the model occurs due to conduction to the various surfaces in the room. In addition, heat transfer can be included by radiative exchange between the upper and lower layers, and between the layers and the surfaces of the room. 

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