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Encontech has developed, constructed and tested a heat-driven refrigeration set-up based on isobaric expansion (IE) engine-compressor.
The IE engine-compressor uses hot water with temperature of 50-60C as a heat source and cooled by tap water with temperature of about 20C.
The set-up generates cold with temperature up to -10C using refrigerant R134a as working fluid.
Basic scheme of the experimental set-up is shown in the figure.
It consists of a driving and refrigeration circuits as well as IE engine-compressor.
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The driving circuit includes a working fluid feed pump P, heater H, regenerator R and cooler C. The refrigeration circuit includes a condenser R1, expansion valve EV and evaporator E. The IE engine-compressor consists of a driver D and compressor C-R parts moving as a unit.
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Isobaric expansion machines as heat driven pumps, compressors and heat-to-electricity converters
The isobaric expansion (IE) engine is a novel, simple, cost-effective and efficient machine for the conversion of low- and medium-grade heat (60C and higher) to mechanical energy or electricity. Generally, the engine is a direct heat-driven pump producing a pressurized flow of liquid i.e. hydraulic power output. In this form, it can be used as an alternative to today’s electricity-driven pumps.
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The hydraulic output can also be converted to shaft power and electricity, turning the machine into a power generator with power up to several MW.
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Liquid compression reactors are novel types of multifunctional chemical reactors in which high pressures and temperatures are generated during a transient compression of a feed by a liquid directly in the reactor. During the following expansion the most energy spent on the compression is recovered whereas the dissipated energy remains in the process inside the liquid. Depending on rate of the compression-expansion cycle the process can be almost isothermal or adiabatic.
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The liquid compression reactors can be used for high pressure processes - polymerization, hydrogenation, hydroformylation etc. They can also process “difficult” feeds such as coal powder and slurries, oil residues, shales or sands, biomass and biomass derived liquids and industrial wastes.
Fisher-Tropsch (FT) or methanol/DME synthesis might be promising applications of the reactors. For these processes the reactors permit to use a low pressure, low quality synthesis gas produced for instance by air-blown gasification of all solid feedstocks from coal to wastes, or by air-blown reforming of natural gas. Moreover it is expected that the compression-expansion reactor cycle can reduce a proportion of heavy hydrocarbons in the FT products or eliminate them completely. All this can make economical small- and medium-size production of synthetic fuels.
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