Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
  • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
  • F25B23/00—Machines, plants or systems, with a single mode of operation not covered by groups F25B1/00 - F25B21/00, e.g. using selective radiation effect

Definitions

• the present invention relates to heat pumps ⁇ devices that move heat from a heat source to a warmer heat sink - being more specifically directed to Bernoulli heat pumps and methodology.
• Heat engines move heat from a source to a sink. Heat engines can be divided into two fundamental classes distinguished by the direction in which heat moves. Heat spontaneously flows “downhill 11 , that is, to lower temperatures. As with the flow of water, "downhill” heat flow can be harnessed to produce mechanical work, as illustrated by internal-combustion engines, e.g. Devices that move heat "uphill", that is, toward higher temperatures, are called heat pumps. Heat pumps necessarily consume power. Refrigerators and air conditioners are examples of heat pumps. Most commonly used heat pumps employ a working fluid (gaseous or liquid) whose temperature is varied over a range that includes the temperatures of both the source and sink between which heat is pumped. This temperature variation is commonly accomplished by compression of the working fluid.
• working fluid gaseous or liquid
• Bernoulli heat pumps effect the required temperature variation by exploiting the well-known Bernoulli principle, according to which random molecular motion (temperature and pressure) is converted into directed motion (macroscopic fluid flow) while leaving the total kinetic energy unchanged. Bernoulli conversion occurs most commonly when the cross- sectional area of a fluid flow is reduced, as in a Venturi-shaped duct wherein the cross- sectional area of fluid flow passes through a minimum along the flow path.
• the fluid may either be a gas or a liquid. Prior examples of such are described by C. H. Barkelew in U. S. patent 3,049,891 , "Cooling by flowing gas at supersonic velocity", 10/21/60; and by
• the directed motion must increase in order to maintain a constant mass flux as the cross-sectional area decreases, as in a garden-hose nozzle.
• Such conversion occurs spontaneously, that is without additional energy, by the local reduction of the random molecular motion, which is reflected in the temperature and pressure.
• compression consumes power
• Bernoulli conversion does not.
• Bernoulli conversion itself consumes no power, the fluid nozzling usually implies strong velocity gradients within the heat-sink flow. Velocity gradients imply viscous losses.
• a challenge central to the development of Bernoulli heat pumps is the discovery and exploitation of structures and materials that facilitate heat transfer while minimizing viscous losses.
• the conventional efficiency metric for heat pumps is the "coefficient of performance” (CoP) which is the ratio of heat-transfer rate to the power consumed.
• CoP coefficient of performance
• the principal source of power consumption is viscous friction within the Venturi neck, where the flow velocity is greatest. Both the temperature difference driving the heat transfer and the viscous dissipation are proportional to the square of the flow velocity.
• Two properties of the working fluid are critical to the efficiency of a Bernoulli heat pump -- its thermal conductivity and its viscosity.
• a dimensionless property of gases, called the Prandtl number is fundamentally the ratio of these two properties.
• the CoP thus benefits directly from the use of materials characterized by small Prandtl numbers.
• a principal object of the invention accordingly, is to provide a new and improved method of operating Bernoulli heat pumps and the like, and novel resulting pump apparatus, that provide efficient heat transfer while minimizing viscous fluid flow losses.
• Another object is to provide for the novel use of rare gases in Bernoulli heat pumps and, preferably, mixtures of such and other gases that provide gas constituents (atoms, molecules) of differing masses -- relatively light and relatively heavy - that give rise to dramatically low Prandtl numbers in the fluid flow operation of the pumps.
• Still another object is to provide such a novel Bernoulli heat pump wherein the heat transfer into the Venturi neck portion exploits the unusual thermodynamic transport properties of rare gases.
• the invention embraces in a Bernoulli heat pump wherein heat is transferred into a neck portion of nozzled heat-sink fluid flow, the method of balancing heat transfer and viscous losses, that comprises, flowing one or more rare gases through the neck as said heat-sink flow while heat is being transferred thereto.
• E at least one solid duct of variable cross-section that imposes a Venturi shape on said heat-sink flow
• heat-sink fluid flow comprises, as a component, at least 1% mole- fraction rare gas.
• the working fluid may be comprised of an elemental rare gas.
• the Prandtl number is proportional to the specific heat, which is, in turn, proportional to the number of degrees of freedom available in the working fluid to absorb energy, the Prandtl number is already relatively small for gases comprised of relatively simple particles. Gases comprised of the simplest particles are the rare gases.
• the elemental rare gases have now proven to be attractive as working fluids for the Bernoulli heat pumps, and they are accordingly preferred for the purposes of the invention, taking advantage of these unusual thermodynamic transport properties of rare gases.
• the present invention thus envisages Bernoulli heat pumps in which the heat-sink fluid flow -- the "working fluid" - is indeed preferably comprised in significant part of a rare gas, or a mixture of rare gases, light and heavy; and, more generally, mixtures of relatively light and heavy gas components as later explained.
• Fig. 1 is a cross-sectional view showing fluid temperature and speed in a Venturi nozzle in which preferably rare gases are a constituent of the fluid for the purposes of the invention.
• Fig. 3 Bernoulli conversion diagram of random-to-directed motion.
• a preferred heat pump of the invention wherein heat transfer from heat-source flow to the neck of the heat-sink Venturi of Fig. 1 provides pumping useful with the preferred rare gas method flow of the invention.
• FIG. 5 closed ductless Bernoulli heat pump useful with rare gas fluids and the like.
• Fig. 6 annular turbine type pump appearing in Figs. 2 and 5.
• Fig. 6a top view of disk containing annular turbine
• Fig. 7 closed duct-based Bernoulli heat pump for use with a rare gas fluid flow of the invention.
• a fluid flow is caused to adopt a Venturi shape, the generic form of which is shown in the varying cross-section solid duct of Fig. 1 , comprising an entrance nozzle portion 1 of the Venturi duct into which a relatively slow hot fluid flow 4 is pressure-driven, converging into an intermediate neck portion 2 of reduced or decreased cross-section, with the flow 5 exiting through a diverging nozzle portion 3 as a relatively fast and cool fluid flow and wherein, in the diverging-nozzle or diffuser portion 3, Bernoulli conversion reverses, producing a slow flow 6 similar to that as the entrance 1 , but heated by the heat transferred to the flow in the neck of the Venturi .
• Blowing mechanisms as in Fig.
• the nozzling can be a self-organized (duct-free) response of the fluid to a low-pressure region maintained by a pump.
• Fig. 2 illustrates such a self-forming Venturi wherein the flow is directed along an entering conversion "nozzle" portion 1 of a Venturi flow into a neck portion 2 and thence through a diverging "nozzle” portion 3.
• an annular turbine 9 sustains flow through circumferential apertures in a disc 7 rotating about the vertical axis 8, and shown more particularly in Figs. 6a and b, wherein the dashed line 15 represents the plane of a side view. Blades of the annular turbine 9 are shown at 14 in Fig. 6b.
• a stator 11 isolates the heat-sink flow and provides a stator heat exchanger 12 that removes heat from the heat-sink flow.
• the heat-source flow is indicated at 10, parallel to the rotation axis 8 of the rotating disc 7 as the annular turbine 9 sustains flow through the disc apparatus in this closed ductless Bernoulli-operating heat pump configuration.
• the Venturi can be fundamentally either one or two dimensional.
• the flow through a garden-hose nozzle can be characterized as fundamentally one dimensional with a line of flow.
• the configuration schematized in Fig.1 can extend into the third dimension perpendicular to the plane of Fig.1. to create a two-dimensional Venturi, nozzle and sheet of flow.
• the required nozzling can be achieved by using a pressure difference to drive the fluid through the duct of varying cross-section.
• a nozzle becomes a heat pump when we allow a second fluid flow, the heat-source flow, to transfer heat into the Bernoulli-cooled necks of the nozzled heat-sink flow 5.
• One such configuration is shown in Fig. 4 wherein the heat-source flow is directed perpendicular to the plane of the diagram.
• a fundamental challenge presented by the Bernoulli heat pump concerns the transfer of heat into the neck of the nozzled heat-sink flow. This is a challenge because thermal equilibration eliminates the relative motion of the heat-sink flow and the solid in the immediate vicinity of the fluid-solid interface. This is the so-called "no-slip boundary condition". While the solid can conduct heat from the source flow to the interface with the sink flow, in order to be convected away by the heat-sink flow, the heat must traverse the boundary layer that separates the solid and cold core of the sink flow. Although the boundary layer is very thin, the fluid constituting the layer is neither rapidly moving nor necessarily cold.
• boundary layer To traverse the boundary layer, heat must be conducted (that is, diffuse) through the boundary layer.
• the thickness of the boundary layer is governed by the viscosity of the sink-flow fluid, and the effectiveness of the thermal conduction is governed by its thermal conductivity. It is therefore not surprising that the dimensionless ratio of the working fluid viscosity to its thermal conductivity is an important design parameter.
• Thermal conductivity is the diffusion of temperature (random motion), while viscosity is the diffusion of flow velocity (directed motion). Thermal conductivity controls the benefit (heat transfer), while viscosity controls the cost of the consumed heat (viscous losses).
• the ratio of the benefit to the cost is called the “coefficient of performance” (CoP) and is fundamentally proportional to the ratio of thermal conductivity to viscosity, which is the inverse of the earlier-discussed dimensionless gas property called the "Prandtl number”.
• the heat-sink fluid flow preferably comprises as a component, at least 1% mole-fraction rare gas - a single rare gas element, or a combination of two or more rare gases such as the before-mentioned heavier xenon and lighter helium, or a mixture of helium and one or more heavier rare-gas elements, and the like.
• Rare gases are also attractive as the working fluid for use in Bernoulli heat pumps in accordance with the methodology of the present invention simply also because they are inert. Thus, their release into the atmosphere has none of the negative implications of conventional coolants.
• Rare gases are also attractive as the working fluid for Bernoulli heat pumps of the invention because the individual atoms comprising the gas possess no internal structure capable of absorbing energy in the temperature range of interest.
• the number of such degrees of freedom enters directly into the specific heat which, in turn, enters both the Prandtl number and the temperature decrease associated with a given flow speed.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Jet Pumps And Other Pumps (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

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• 2006
  • 2006-08-09 WO PCT/IB2006/002176 patent/WO2007017741A2/fr active Application Filing
  • 2006-08-09 BR BRPI0614540-0A patent/BRPI0614540A2/pt not_active Application Discontinuation
  • 2006-08-09 AT AT06795223T patent/ATE548613T1/de active
  • 2006-08-09 JP JP2008525656A patent/JP2010500524A/ja active Pending
  • 2006-08-09 CA CA002618728A patent/CA2618728A1/fr not_active Abandoned
  • 2006-08-09 KR KR1020087005468A patent/KR20080059552A/ko not_active Application Discontinuation
  • 2006-08-09 CN CNA2006800332960A patent/CN101317047A/zh active Pending
  • 2006-08-09 AU AU2006277743A patent/AU2006277743A1/en not_active Abandoned
  • 2006-08-09 EP EP06795223A patent/EP1963756B1/fr not_active Not-in-force
• 2008
  • 2008-02-11 IL IL189426A patent/IL189426A0/en unknown

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