WO2011119338A1 - Cooling systems utilizing a supersonic cooling cycle - Google Patents

Cooling systems utilizing a supersonic cooling cycle Download PDF

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Publication number
WO2011119338A1
WO2011119338A1 PCT/US2011/027845 US2011027845W WO2011119338A1 WO 2011119338 A1 WO2011119338 A1 WO 2011119338A1 US 2011027845 W US2011027845 W US 2011027845W WO 2011119338 A1 WO2011119338 A1 WO 2011119338A1
Authority
WO
WIPO (PCT)
Prior art keywords
cooling
fluid
fluid flow
psi
evaporator
Prior art date
Application number
PCT/US2011/027845
Other languages
French (fr)
Inventor
Jayden David Harman
Kristian Debus
Thomas Gielda
Don Tomasi
Original Assignee
Caitin, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US12/732,171 external-priority patent/US8333080B2/en
Priority claimed from US12/880,940 external-priority patent/US20110048062A1/en
Priority claimed from US12/902,060 external-priority patent/US20110048048A1/en
Priority claimed from US12/902,056 external-priority patent/US8505322B2/en
Application filed by Caitin, Inc. filed Critical Caitin, Inc.
Publication of WO2011119338A1 publication Critical patent/WO2011119338A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A41WEARING APPAREL
    • A41DOUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
    • A41D13/00Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches
    • A41D13/002Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches with controlled internal environment
    • A41D13/005Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches with controlled internal environment with controlled temperature
    • A41D13/0053Cooled garments
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00Compression machines, plants or systems with non-reversible cycle

Definitions

  • the present invention generally relates to cooling systems.
  • the present invention more specifically relates to utilizing a supersonic cooling system to remove heat from various heat producing sources.
  • FIGURE 1 illustrates a vapor compression system 100 as might be found in the prior art.
  • compressor 110 compresses the gas to (approximately) 238 pounds per square inch (PSI) and a temperature of 190° F.
  • Condenser 120 then liquefies the heated and compressed gas to (approximately) 220 PSI and 117° F.
  • the gas that was liquefied by the condenser 120 is then passed through the expansion valve 130 of FIGURE 1. By passing the liquefied gas through expansion valve 130, the pressure is dropped to (approximately) 20 PSI.
  • a corresponding drop in temperature accompanies the drop in pressure, which is reflected as a temperature drop to (approximately) 34 0 F in FIGURE 1.
  • the refrigerant that results from dropping the pressure and temperature at the expansion valve 130 is boiled at evaporator 140. Through boiling of the refrigerant by evaporator 140, a low temperature vapor results, which is illustrated in FIGURE 1 as having (approximately) a temperature of 39 0 F and a corresponding pressure of 20 PSI.
  • the cycle related to the system 100 of FIGURE 1 is sometimes referred to as the vapor compression cycle. Such a cycle generally results in a coefficient of performance (COP) between 2.4 and 3.5.
  • the coefficient of performance, as reflected in FIGURE 1, is the evaporator cooling power or capacity divided by compressor power. It should be noted that the temperature and pressure references that are reflected in FIGURE 1 are exemplary and illustrative.
  • FIGURE 2 illustrates the performance of a vapor compression system like that illustrated in FIGURE 1.
  • the COP illustrated in FIGURE 2 corresponds to a typical home or automotive vapor compression system— like that of FIGURE 1— operating in an ambient temperature of (approximately) 90 0 F.
  • the COP shown in FIGURE 2 further corresponds to a vapor compression system utilizing a fixed orifice tube system.
  • Such a system 100 operates at an efficiency rate (i.e., COP) that is far below that of system potential.
  • COP efficiency rate
  • To compress gas in a conventional vapor compression system 100 like that illustrated in FIGURE 1 typically takes 1.75 - 2.5 kilowatts for every 5 kilowatts of cooling power generated. This exchange rate is less than optimal and directly correlates to the rise in pressure times the volumetric flow rate. Degraded performance is similarly and ultimately related to performance (or lack thereof) by the compressor 110.
  • Haloalkane refrigerants such as tetrafluoroethane (CH2FCF3) are inert gases that are commonly used as high-temperature refrigerants in refrigerators and automobile air conditioners. Haloalkane refrigerants have also been used to cool over-clocked computers. These inert, refrigerant gases are more commonly referred to as R-134 gases. The volume of an R-134 gas can be 600-1000 times greater than the corresponding liquid.
  • a vapor compression system as known in the art generally includes a compressor, a condenser, an evaporator, and an expansion device. Apart from issues of non-optimal efficiency, simply the combined weight of these elements may be a detriment to the efficacy of the prior compression cooling cycle in non- stationary cooling systems.
  • the cooling system disclosed herein is a personal cooling unit.
  • the personal cooling unit disclosed herein includes a garment, the garment including a cooling fluid circulation path to carry cooling fluid throughout the garment.
  • the cooling fluid circulation path may include a manifold coupled to a cooling fluid supply.
  • the cooling fluid circulation path may include one or more branches coupled to the manifold.
  • the unit further includes at least one pump that maintains the flow through the cooling fluid circulation path and a fluid flow path.
  • the unit also includes an evaporator that operates in the critical flow regime of the circulatory fluid in the fluid flow path.
  • the evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow. No heat is added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator.
  • the evaporator may use one or more tubes/nozzles, and may generate approximately 300 watts of cooling power at 38° C ambient.
  • a heat exchanging mechanism may be thermally coupled to the fluid flow path.
  • the heat exchanging mechanism may utilize at least a portion of an external surface of the control pack to vent heat to the atmosphere via convection from the surface.
  • the heat exchanging mechanism may include one or more vents.
  • a plurality of fins may be employed in the vents.
  • a control pack may be mounted on the body of the user.
  • a thermostat may be included in the control pack to control the temperature of the unit.
  • the control pack may further include a battery, and a solar cell that may be used to power the unit or to recharge the battery.
  • Operating conditions within the unit may include the pump raising the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSI. In certain embodiments, the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSI.
  • a personal cooling unit as disclosed herein may include a pump that maintains a fluid flow of a fluid through the unit, and an evaporator that effects a phase change in the fluid. The unit may establish a compression wave in the fluid by passing the fluid from a high pressure region to a low pressure region, the velocity of the fluid being equal to or greater than the speed of sound in the fluid. The fluid is cooled during a phase change so that heat may be transferred from the unit by thermally coupling one or more fins between the fluid and the ambient atmosphere.
  • Operating conditions in the evaporator may include a pressure drop in the cooling liquid to approximately 5.5 PSL A corresponding phase change results in a lowered temperature of the cooling liquid.
  • the pressure change may occur within a range of approximately 20 PSI to 100 PSI, or the increased pressure may be in excess of 100 PSI, such as 300 or 500 PSI.
  • the portable cooling unit includes a pump that maintains a circulatory fluid flow through a flow path.
  • the unit also includes an evaporator that operates in the critical flow regime of the circulatory fluid.
  • the evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow. No heat is added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator.
  • the evaporator may use one or more tubes/nozzles, and may generate 20-80 watts of cooling power.
  • the unit further includes a storage compartment, the storage
  • the storage compartment may form a housing for the pump and the evaporator.
  • An external surface of the storage compartment may effectuate convection and further exchange heat introduced into the unit.
  • the unit may be powered by an adapter such as for a vehicle battery. Moreover, the unit may be powered by a self-contained battery pack. The unit may use a solar cell as a direct power source or as a means of charging a battery pack.
  • Operating conditions within the unit may include the pump raising the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSL In certain embodiments, the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSL
  • a portable cooling unit as disclosed herein may include a storage compartment that receives items to be cooled or maintained at a temperature below ambient.
  • the unit may also include a pump that maintains a fluid flow of a fluid through the unit, and an evaporator that effects a phase change in the fluid.
  • the unit may establish a compression wave in the fluid by passing the fluid from a high pressure region to a low pressure region, the velocity of the fluid being greater than or equal to the speed of sound in the fluid.
  • the fluid is cooled during a phase change so that heat may be transferred from the unit by thermally coupling one or more fins between the fluid and the ambient atmosphere.
  • Operating conditions in the evaporator may include a pressure drop in the cooling liquid to approximately 5.5 PSI. A corresponding phase change results in a lowered temperature of the cooling liquid.
  • the pressure change may occur within a range of approximately 20 PSI to 100 PSI, or the increased pressure may be in excess of 100 PSI, such as 300 or 500 PSI.
  • the battery cooling unit includes a cooling fluid circulation path in thermal contact with at least one battery cell in a battery pack.
  • the cooling fluid circulation path may include a cooling jacket.
  • the cooling jacket may be thermally coupled to at least a portion of the battery pack.
  • the cooling jacket may include a plurality of receptacles, each receptacle receiving a cell of the battery pack, or the cooling jacket may surround an exterior of the battery pack.
  • a housing of the cooling jacket may be rigid or flexible, depending on the parameters of a given application.
  • the battery cooling unit further includes a pump that maintains a circulatory fluid flow through the cooling fluid circulation path and a working fluid flow path.
  • the unit also includes an evaporator that operates in the critical flow regime of the circulatory working fluid. The evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow.
  • the evaporator may use one or more tubes/nozzles.
  • Operating conditions within the unit may include the pump raising the pressure of the circulatory working fluid flow from approximately 20 PSI to approximately 100 PSI.
  • the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSI.
  • a battery cooling unit may include a cooling fluid circulation path in close proximity to at least one battery cell in a battery pack.
  • the unit may include a pump that maintains a fluid flow through a working fluid flow path, and at least one evaporator that operates in the critical flow regime of the working fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow to cool the working fluid, the evaporator being in close proximity to the at least one battery cell so that heat is removed from the battery cell via conduction.
  • Another battery cooling unit may include a series of single tube evaporators aligned in parallel, each tube being in close proximity to a battery cell. This allows the working fluid of the evaporators to remove heat from the battery cells via conduction.
  • FIGURE 1 illustrates a vapor compression system as might be found in the prior art.
  • FIGURE 2 shows the performance of a vapor compression system like that illustrated in FIGURE 1.
  • FIGURE 3 illustrates an exemplary cooling system in accordance with an embodiment of the present invention.
  • FIGURE 4 illustrates an exemplary cooling system in accordance with another embodiment of the present invention.
  • FIGURE 5 illustrates performance of a cooling system like that illustrated in FIGURES 3 and 4.
  • FIGURE 6 illustrates the operation of a single evaporator tube / nozzle cooling system.
  • FIGURE 7 illustrates a personal cooling unit mounted on the back of a user.
  • FIGURE 8 illustrates a personal cooling unit mounted on the leg of a user.
  • FIGURE 9 illustrates a personal cooling unit utilizing a tight fitting garment.
  • FIGURE 10 illustrates a portable cooling unit.
  • FIGURE 11 illustrates a battery cooling unit utilizing a cooling jacket surrounding a battery pack.
  • FIGURE 12 illustrates a battery cooling unit utilizing a cooling jacket surrounding the individual cells of a battery pack.
  • FIGURE 13 illustrates a method of operation for a cooling system utilizing a supersonic cooling cycle.
  • FIGURE 3 illustrates an exemplary cooling system 300 utilizing a supersonic cooling cycle in accordance with an embodiment of the present invention.
  • the cooling system 300 does not need to compress a gas as otherwise occurs at compressor 110 in the prior art vapor compression system 100 illustrated in FIGURE 1.
  • Cooling system 300 operates by pumping liquid. Because cooling system 300 pumps liquid, the compression cooling system 300 does not require the use of a condenser 120 as does the prior art compression system 100. Compression cooling system 300 instead utilizes a compression wave.
  • the evaporator of cooling system 300 operates in the critical flow regime where the pressure in an evaporator tube will remain almost constant and then 'jump' or 'shock up' to the ambient pressure.
  • the cooling system 300 of FIGURE 3 recognizes a heightened degree of efficiency in that the pump 320 of the system 300 is not required to draw as much power as the compressor 110 in a prior art compression system 100 like that illustrated in FIGURE 1.
  • a prior art compression system 100 as illustrated in FIGURE 1 may require 1.75-2.5 kilowatts to generate 5 kilowatts of cooling power.
  • Prior art compression system 100 therefore may operate at a coefficient of performance (COP) of less than 3.
  • a system 300 like that illustrated in FIGURE 3 may pump fluid from approximately 14.7 to approximately 120 PSI with the pump drawing power at approximately 500W (0.5 kilowatts), with the system 300 also generating 5 kilowatts of cooling power.
  • the system 300 may therefore operate with a COP of 10.
  • system 300 may utilize many working fluids, including but not limited to water.
  • the cooling system 300 of FIGURE 3 may include a housing 310.
  • the general shape of housing 310 of FIGURE 3 is akin to that of a pumpkin.
  • the particular shape or other design features of housing 310 may be a matter of aesthetics and convenience with respect to where and how the system 300 is installed.
  • the design of the housing 310 may be influenced by the facility in which the system 300 is installed, or by the equipment or machinery to which the system 300 is coupled.
  • housing 310 encloses pump 330, evaporator 350, and the attendant accessory equipment or flow paths (e.g., pump inlet 340 and evaporator tube 360).
  • Housing 310 also contains the working fluid to be used by the system 300.
  • Housing 310 in an alternative embodiment, may also encompass a secondary heat exchanger as in system 400, which is illustrated in FIGURE 4.
  • the secondary heat exchanger is not necessarily contained within the housing 310.
  • the outer surface area of the system 400— that is, the housing 310— may be utilized in a cooling process through forced convection on the external surface of the housing 310.
  • Pump 330 may be powered by a motor 320, which may be external to the system 300 and which is located outside the housing 310 in FIGURE 3. Motor 320 may alternatively be contained within the housing 310 of system 300. Motor 320 may drive the pump 330 of FIGURE 3 through a rotor drive shaft with a corresponding bearing and seal or magnetic induction, whereby penetration of the housing 310 is not required. Other motor designs may be utilized with respect to motor 320 and corresponding pump 330 including synchronous, alternating (AC), and direct current (DC) motors.
  • AC alternating
  • DC direct current
  • system 300 Other electric motors that may be used with system 300 include induction motors; brushed and brushless DC motors; stepper, linear, unipolar, and reluctance motors; and ball bearing, homopolar, piezoelectric, ultrasonic, and electrostatic motors.
  • Pump 330 establishes circulation of a compressible working fluid through the interior fluid flow paths of system 300, the flow paths being contained within the housing 310. Pump 330 may circulate the working fluid throughout system 300 through the use of vortex flow rings. Vortex rings operate as energy reservoirs whereby added energy is stored in the vortex ring. The progressive introduction of energy to a vortex ring via pump 330 causes the corresponding ring vortex to function at a level such that energy lost through dissipation corresponds to energy being input. [047] Pump 330 operates to raise the pressure of a liquid being used by system 300 from, for example, 20 PSI to 100 PSI or more. Some systems may operate at an increased pressure of approximately 300 PSI. Other systems may operate at an increased pressure of approximately 500 PSI.
  • Pump inlet 340 introduces a liquid to be used in cooling and otherwise resident in system 300 into pump 330.
  • Fluid temperature may, at this point in the system 300, be approximately 95 F.
  • the working fluid introduced to pump 330 by inlet 340 traverses a primary fluid flow path to nozzle / evaporator 350.
  • Evaporator 350 induces a pressure drop (e.g., to approximately 5.5 PSI) and phase change that results in a low temperature.
  • the working fluid further 'boils off at evaporator 350, whereby the resident liquid may be used as a coolant.
  • the liquid coolant may be water cooled to 35-45° F (approximately 37 ° F as illustrated in FIGURE 3).
  • the system 300 (specifically evaporator 350) operates in the critical flow regime, thereby generating a compression wave.
  • the working fluid exits the evaporator 350 via evaporator tube 360 where the fluid is 'shocked up' to approximately 20 PSI because the flow in the evaporator tube 360 is in the critical regime.
  • the nozzle / evaporator 350 and evaporator tube 360 may be integrated and/or collectively referred to as an evaporator.
  • the working fluid of system 300 may be cooled at a heat exchanger to assist in dissipating absorbed heat, the temperature of the fluid being approximately 90-100° F after having exited evaporator 350.
  • the housing 310 of the system 300 may be used to cool via convection.
  • FIGURE 5 illustrates an exemplary performance cycle of a cooling system utilizing a supersonic cooling cycle such as the systems illustrated in FIGURES 3 and 4. The operating steps of the method utilized in system 300 are described in further detail below with reference to FIGURE 13.
  • FIGURE 6 illustrates the operation of an exemplary cooling system 600 that utilizes a supersonic cooling cycle.
  • the system 600 utilizes a small pump 610, which may be of any type, and at least one evaporator or tube 620.
  • the tube 620 may have a converging - diverging conformation.
  • the tube 620 functions as the evaporator in the system 600.
  • FIGURE 6 illustrates a supersonic cooling system 600 in which a single evaporator tube 620 is utilized, a configuration that may typically be implemented in installations requiring a cooling power of, for example, 300 watts.
  • more than one evaporator tube 620 may be employed (as illustrated in FIGURES 3 and 4) depending on the requirements of a given application.
  • a heat exchanger 630 may be employed in a fluid flow path in the system 600 to remove heat from the system.
  • the heat exchanger 630 is utilized in the transfer of heat away from the body of the user of the system.
  • the pump 610 raises the pressure of a fluid in the system 600.
  • Various fluids including water, may be used in the system.
  • Other refrigerants such as green refrigerant R134a may also be used.
  • the pressure of the fluid may be raised from 20 PSI to in excess of 100 PSI.
  • the fluid flows through the tube 620 of the evaporator. Pressure drop and phase change that occur as the fluid is accelerated through the tube 620 result in a lowered temperature of the fluid in the tube 620 and provide the cooling power for the system 600.
  • Critical flow rate which is the maximum flow rate that can be attained by a compressible fluid as that fluid passes from a high pressure region to a low pressure region (i.e., the critical flow regime), allows for a compression wave to be established and utilized in the critical flow regime.
  • Critical flow occurs when the velocity of the fluid is equal to or greater than the speed of sound in the fluid.
  • the pressure in the channel may not be influenced by the exit pressure, and at or near the channel exit, the fluid will 'shock up' to the ambient condition. In critical flow the fluid will also stay at the low pressure and temperature corresponding to the saturation pressure.
  • cooling system 600 the cooled working fluid is passed through heat exchanger 630 to effectuate a heat transfer to the atmosphere.
  • the operating steps of the method utilized in system 600 are further described below with reference to FIGURE 13.
  • FIGURE 7 illustrates an exemplary embodiment of a cooling system 600, a personal cooling unit 700.
  • FIGURE 7 shows a full body garment 710 used in one implementation of the personal cooling unit 700.
  • the garment chosen may cover any part of the body chosen by the user.
  • Suitable garments for various configurations of the personal cooling unit 700 include, but are not limited to, full body garments such as overalls or jumpsuits, vests, shirts, pants, and hats. In short, any part of the body that the user desires to cool may be matched to a garment equipped with the personal cooling unit 700.
  • the garment 710 of the cooling unit 700 includes a cooling fluid circulation path 920 (see FIGURE 9) thermally coupled to the fluid flow path of the working fluid of the supersonic cooling cycle of the unit.
  • the cooling fluid circulation path 920 carries cooling fluid throughout the garment. As the cooling fluid flows through the cooling fluid circulation path 920, the cooling fluid is subject to warming due to ambient and body heat. In units utilizing a full body garment, warming of the fluid in the cooling fluid circulation path 920 can be a significant problem. Therefore, the cooling fluid circulation path 920 may be a manifolded capillary system to reduce the length of any given branch in the unit. Minimizing the lengths of the branches in the cooling fluid circulation path 920 reduces the possibility of the cooling fluid absorbing too much heat to properly cool the user.
  • a control pack 720 may include a thermostat to control the temperature of the unit.
  • the unit will typically be operated to maintain a temperature in the garment of between 12° C and 24° C.
  • the control pack 720 may also include an on/off switch that controls the power supply to the cooling unit 700. The user may control the temperature in the cooling unit 700 by simply turning the power on and off as necessary to maintain a comfortable temperature.
  • Heat may be vented from the cooling unit 700 via vents 730 in the surface of the control pack 720.
  • the vents 730 may be a series of fins to increase the surface area available for heat transfer.
  • the vents may also be holes, slots, or any other construction that would facilitate the transfer of heat.
  • Personal cooling unit 700 may be powered by a 12 or 24 volt power supply.
  • the personal cooling unit 700 may be powered by self-contained batteries or by a solar cell.
  • a solar cell may also be used to charge the self-contained batteries.
  • power supply configurations may be utilized in the personal cooling unit 700.
  • personal cooling unit 700 may have the control pack 720 mounted on the back of the user, akin to a backpack.
  • the position in which the control pack 720 is mounted may vary with a given application.
  • the mounting of the control pack 720 is a matter of choice of the user of the unit.
  • the unit may be mounted on the user's back as shown in FIGURE 7 or on the leg as shown in FIGURE 8.
  • the control pack 720 may be mounted at any location that is convenient for the user.
  • FIGURE 9 illustrates a personal cooling unit 900 that utilizes a tight fitting garment 910.
  • Garment 910 may be made from a stretchable fabric such as Spandex, Lycra, etc., to hold the cooling fluid in the cooling fluid circulation path 920 in close proximity to the body of the user.
  • a manifolded cooling fluid supply 930 routes cooling fluid cooled by the working fluid in the fluid flow path through the cooling fluid circulation path 920.
  • the cooling fluid circulation path 920 is thermally coupled to the fluid flow path of a supersonic cooling cycle.
  • the cooling fluid circulation path 920 may trace, as illustrated in FIGURE 9, the main arteries of the body of the user. Positioning the cooling fluid circulation path 920 so that it traces the main arteries of the user may increase the efficiency of heat dissipation from the body of the user.
  • FIGURE 10 shows an exemplary embodiment of a portable cooling unit 1000 that utilizes the supersonic cooling cycle.
  • Portable cooling unit 1000 may be powered by a 12 volt power supply, such as a car battery.
  • An adapter 1010 that plugs into a power outlet such as those commonly found in vehicles may be provided with the portable cooling unit 1000.
  • Portable cooling unit 1000 may also be powered by self-contained batteries or a solar cell. A solar cell may also be used to charge the self-contained batteries.
  • Those skilled in the art will recognize that many power supply configurations may be utilized in the portable cooling unit 1000.
  • the housing 1020 of the cooling unit 1000 may include one or more fins 1030.
  • the fins 1030 may be coupled to the working fluid in the portable cooling unit 1000, and may be open to the atmosphere.
  • the fins 1030 may therefore be used as a radiator to transfer heat from the interior of the unit 1000 to the exterior atmosphere.
  • FIGURE 11 illustrates a battery cooling system 1100 that may be utilized in conjunction with the supersonic cooling cycle as illustrated in FIGURE 4.
  • the cooling cycle shown in FIGURE 4 may be adapted to utilize the single nozzle cycle depicted in FIGURE 6.
  • a cooling fluid circulation path of the system 1100 routes the secondary cooling fluid through battery cooling system 1100.
  • the battery cooling system 1100 may be used to cool high power battery packs, including but not limited to those that may be utilized in EV (electric vehicle) or HEV (hybrid electric vehicle) applications.
  • a battery pack 1110 may be cooled by a cooling jacket 1120 in an implementation of the battery cooling system 1100 as illustrated in FIGURE 11.
  • the cooling jacket 1120 surrounds the exterior of battery pack 1110.
  • the cooling element, cooling jacket 1120 may accommodate whatever fluid is chosen to be used as the cooling fluid. Water and other fluids may be used as the cooling fluid in the system 1100.
  • Cooling jacket 1120 may include either a rigid or a flexible housing. The choice of housing depends on the requirements of a given application.
  • the cooling fluid circulation path routes the cooling fluid through the cooling jacket 1120.
  • the cooling fluid in the circulation path removes heat from the battery pack.
  • the cooling fluid flows into the cooling jacket 1120 through an inlet 1130, and out of the jacket 1120 through an outlet 1140.
  • Battery cooling system 1100 may be powered from the battery pack which it is cooling, or from an independent volt power supply, typically a 12 or 24 volt power supply. If an independent power supply is utilized, the power supply may be self-contained batteries or a solar cell. A solar cell may also be used to charge self- contained batteries. Those skilled in the art will recognize that many power supply configurations may be utilized in the battery cooling system 1100.
  • FIGURE 12 shows a battery cooling system 1200 with a battery pack that includes a plurality of battery cells 1210.
  • the cooling jacket 1220 includes a plurality of receptacles 1230. Each receptacle 1230 may receive a battery cell 1210.
  • the cooling fluid circulation path of cooling system 1200 flows around one or more of the battery cells 1210 contained in receptacles 1230 to remove heat from the battery pack.
  • the cooling fluid flows into the cooling jacket 1220 through an inlet 1240, and out through an outlet 1250.
  • FIGURE 13 illustrates a method of operation 1300 for the cooling cycles utilized in the systems disclosed herein.
  • a pump raises the pressure of a liquid.
  • the pressure may, for example, be raised from 20 PSl to in excess of 100 PSL As mentioned above, the increased pressure may be 300 PSl or even 500 PSL
  • Critical flow rate which is the maximum flow rate that can be attained by a compressible fluid as that fluid passes from a high pressure region to a low pressure region (i.e., the critical flow regime), allows for a compression wave to be established and utilized in the critical flow regime.
  • Critical flow occurs when the velocity of the fluid is equal to or greater than the speed of sound in the fluid.
  • the pressure in the channel will not be influenced by the exit pressure and at or near the channel exit, the fluid will "shock up" to the ambient condition. In critical flow the fluid will also stay at the low pressure and temperature
  • step 1340 upon the fluid exiting the evaporator tube, the fluid "shocks up" to 20 PSI.
  • a heat exchanger may be used in optional step 1350. Cooling may also occur via convection on the surface of the housings of the cooling systems that utilize the supersonic cooling cycle.

Abstract

A supersonic cooling system operates by pumping liquid into an evaporator situated in a working fluid flow path. Because the cooling system pumps liquid, the compression cooling cycle that generates the cooling power does not require the use of a condenser. An evaporator of the cooling system operates in the critical flow regime and forms a compression wave to facilitate a phase change in a working fluid. The pressure in the evaporator remains almost constant and then 'jumps' or 'shocks up' to an increased pressure as the working fluid exits the evaporator.

Description

COOLING SYSTEMS UTILIZING A SUPERSONIC COOLING CYCLE
BACKGROUND OF THE INVENTION
Field of the Invention
[01] The present invention generally relates to cooling systems. The present invention more specifically relates to utilizing a supersonic cooling system to remove heat from various heat producing sources.
Description of the Related Art
[02] In a prior art vapor compression system, a gas is compressed so that the temperature of that gas is increased beyond that of the ambient temperature. The compressed gas is then run through a condenser and turned into a liquid. The condensed and liquefied gas is then taken through an expansion device, which drops the pressure and the corresponding temperature. The resulting refrigerant is then boiled in an evaporator. This vapor compression cycle is generally known to those of skill in the art.
[03] FIGURE 1 illustrates a vapor compression system 100 as might be found in the prior art. In the prior art vapor compression system 100 of FIGURE 1, compressor 110 compresses the gas to (approximately) 238 pounds per square inch (PSI) and a temperature of 190° F. Condenser 120 then liquefies the heated and compressed gas to (approximately) 220 PSI and 117° F. The gas that was liquefied by the condenser 120 is then passed through the expansion valve 130 of FIGURE 1. By passing the liquefied gas through expansion valve 130, the pressure is dropped to (approximately) 20 PSI. A corresponding drop in temperature accompanies the drop in pressure, which is reflected as a temperature drop to (approximately) 340 F in FIGURE 1. The refrigerant that results from dropping the pressure and temperature at the expansion valve 130 is boiled at evaporator 140. Through boiling of the refrigerant by evaporator 140, a low temperature vapor results, which is illustrated in FIGURE 1 as having (approximately) a temperature of 390 F and a corresponding pressure of 20 PSI. [04] The cycle related to the system 100 of FIGURE 1 is sometimes referred to as the vapor compression cycle. Such a cycle generally results in a coefficient of performance (COP) between 2.4 and 3.5. The coefficient of performance, as reflected in FIGURE 1, is the evaporator cooling power or capacity divided by compressor power. It should be noted that the temperature and pressure references that are reflected in FIGURE 1 are exemplary and illustrative.
[05] FIGURE 2 illustrates the performance of a vapor compression system like that illustrated in FIGURE 1. The COP illustrated in FIGURE 2 corresponds to a typical home or automotive vapor compression system— like that of FIGURE 1— operating in an ambient temperature of (approximately) 900 F. The COP shown in FIGURE 2 further corresponds to a vapor compression system utilizing a fixed orifice tube system.
[06] Such a system 100, however, operates at an efficiency rate (i.e., COP) that is far below that of system potential. To compress gas in a conventional vapor compression system 100 like that illustrated in FIGURE 1 typically takes 1.75 - 2.5 kilowatts for every 5 kilowatts of cooling power generated. This exchange rate is less than optimal and directly correlates to the rise in pressure times the volumetric flow rate. Degraded performance is similarly and ultimately related to performance (or lack thereof) by the compressor 110.
[07] Haloalkane refrigerants such as tetrafluoroethane (CH2FCF3) are inert gases that are commonly used as high-temperature refrigerants in refrigerators and automobile air conditioners. Haloalkane refrigerants have also been used to cool over-clocked computers. These inert, refrigerant gases are more commonly referred to as R-134 gases. The volume of an R-134 gas can be 600-1000 times greater than the corresponding liquid.
[08] In light of the theoretical efficiencies of systems using haloalkanes or other fluids, there is a need in the art for an improved cooling system that more fully recognizes system potential and overcomes technical barriers related to compressor performance.
[09] Moreover, a vapor compression system as known in the art generally includes a compressor, a condenser, an evaporator, and an expansion device. Apart from issues of non-optimal efficiency, simply the combined weight of these elements may be a detriment to the efficacy of the prior compression cooling cycle in non- stationary cooling systems.
SUMMARY OF THE CLAIMED INVENTION
[010] One embodiment of the cooling system disclosed herein is a personal cooling unit. The personal cooling unit disclosed herein includes a garment, the garment including a cooling fluid circulation path to carry cooling fluid throughout the garment. The cooling fluid circulation path may include a manifold coupled to a cooling fluid supply. The cooling fluid circulation path may include one or more branches coupled to the manifold.
[Oil] The unit further includes at least one pump that maintains the flow through the cooling fluid circulation path and a fluid flow path. The unit also includes an evaporator that operates in the critical flow regime of the circulatory fluid in the fluid flow path. The evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow. No heat is added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator. The evaporator may use one or more tubes/nozzles, and may generate approximately 300 watts of cooling power at 38° C ambient.
[012] A heat exchanging mechanism may be thermally coupled to the fluid flow path. The heat exchanging mechanism may utilize at least a portion of an external surface of the control pack to vent heat to the atmosphere via convection from the surface. The heat exchanging mechanism may include one or more vents. A plurality of fins may be employed in the vents.
[013] A control pack may be mounted on the body of the user. A thermostat may be included in the control pack to control the temperature of the unit. The control pack may further include a battery, and a solar cell that may be used to power the unit or to recharge the battery.
[014] Operating conditions within the unit may include the pump raising the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSI. In certain embodiments, the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSI. [015] A personal cooling unit as disclosed herein may include a pump that maintains a fluid flow of a fluid through the unit, and an evaporator that effects a phase change in the fluid. The unit may establish a compression wave in the fluid by passing the fluid from a high pressure region to a low pressure region, the velocity of the fluid being equal to or greater than the speed of sound in the fluid. The fluid is cooled during a phase change so that heat may be transferred from the unit by thermally coupling one or more fins between the fluid and the ambient atmosphere.
[016] Operating conditions in the evaporator may include a pressure drop in the cooling liquid to approximately 5.5 PSL A corresponding phase change results in a lowered temperature of the cooling liquid. The pressure change may occur within a range of approximately 20 PSI to 100 PSI, or the increased pressure may be in excess of 100 PSI, such as 300 or 500 PSI.
[017] Another embodiment of the cooling system disclosed herein is a portable cooling unit. The portable cooling unit includes a pump that maintains a circulatory fluid flow through a flow path. The unit also includes an evaporator that operates in the critical flow regime of the circulatory fluid. The evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow. No heat is added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator. The evaporator may use one or more tubes/nozzles, and may generate 20-80 watts of cooling power.
[018] The unit further includes a storage compartment, the storage
compartment receiving items to be cooled or maintained at a temperature below ambient. The storage compartment may form a housing for the pump and the evaporator. An external surface of the storage compartment may effectuate convection and further exchange heat introduced into the unit.
[019] The unit may be powered by an adapter such as for a vehicle battery. Moreover, the unit may be powered by a self-contained battery pack. The unit may use a solar cell as a direct power source or as a means of charging a battery pack.
[020] Operating conditions within the unit may include the pump raising the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSL In certain embodiments, the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSL
[021] A portable cooling unit as disclosed herein may include a storage compartment that receives items to be cooled or maintained at a temperature below ambient. The unit may also include a pump that maintains a fluid flow of a fluid through the unit, and an evaporator that effects a phase change in the fluid. The unit may establish a compression wave in the fluid by passing the fluid from a high pressure region to a low pressure region, the velocity of the fluid being greater than or equal to the speed of sound in the fluid. The fluid is cooled during a phase change so that heat may be transferred from the unit by thermally coupling one or more fins between the fluid and the ambient atmosphere.
[022] Operating conditions in the evaporator may include a pressure drop in the cooling liquid to approximately 5.5 PSI. A corresponding phase change results in a lowered temperature of the cooling liquid. The pressure change may occur within a range of approximately 20 PSI to 100 PSI, or the increased pressure may be in excess of 100 PSI, such as 300 or 500 PSI.
[023] Still another embodiment of the cooling system disclosed herein is a battery cooling unit. The battery cooling unit includes a cooling fluid circulation path in thermal contact with at least one battery cell in a battery pack. The cooling fluid circulation path may include a cooling jacket. The cooling jacket may be thermally coupled to at least a portion of the battery pack. The cooling jacket may include a plurality of receptacles, each receptacle receiving a cell of the battery pack, or the cooling jacket may surround an exterior of the battery pack. A housing of the cooling jacket may be rigid or flexible, depending on the parameters of a given application.
[024] The battery cooling unit further includes a pump that maintains a circulatory fluid flow through the cooling fluid circulation path and a working fluid flow path. The unit also includes an evaporator that operates in the critical flow regime of the circulatory working fluid. The evaporator generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow and exchanging heat introduced into the circulatory fluid flow. The evaporator may use one or more tubes/nozzles.
[025] Operating conditions within the unit may include the pump raising the pressure of the circulatory working fluid flow from approximately 20 PSI to approximately 100 PSI. In certain embodiments, the pressure may be raised to pressures in excess of 100 PSI, such as 300 or 500 PSI.
[026] A battery cooling unit according to the technology disclosed herein may include a cooling fluid circulation path in close proximity to at least one battery cell in a battery pack. The unit may include a pump that maintains a fluid flow through a working fluid flow path, and at least one evaporator that operates in the critical flow regime of the working fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow to cool the working fluid, the evaporator being in close proximity to the at least one battery cell so that heat is removed from the battery cell via conduction.
[027] Another battery cooling unit may include a series of single tube evaporators aligned in parallel, each tube being in close proximity to a battery cell. This allows the working fluid of the evaporators to remove heat from the battery cells via conduction.
BRIEF DESCRIPTION OF THE DRAWINGS
[028] FIGURE 1 illustrates a vapor compression system as might be found in the prior art.
[029] FIGURE 2 shows the performance of a vapor compression system like that illustrated in FIGURE 1.
[030] FIGURE 3 illustrates an exemplary cooling system in accordance with an embodiment of the present invention.
[031] FIGURE 4 illustrates an exemplary cooling system in accordance with another embodiment of the present invention.
[032] FIGURE 5 illustrates performance of a cooling system like that illustrated in FIGURES 3 and 4.
[033] FIGURE 6 illustrates the operation of a single evaporator tube / nozzle cooling system.
[034] FIGURE 7 illustrates a personal cooling unit mounted on the back of a user.
[035] FIGURE 8 illustrates a personal cooling unit mounted on the leg of a user.
[036] FIGURE 9 illustrates a personal cooling unit utilizing a tight fitting garment.
[037] FIGURE 10 illustrates a portable cooling unit.
[038] FIGURE 11 illustrates a battery cooling unit utilizing a cooling jacket surrounding a battery pack.
[039] FIGURE 12 illustrates a battery cooling unit utilizing a cooling jacket surrounding the individual cells of a battery pack.
[040] FIGURE 13 illustrates a method of operation for a cooling system utilizing a supersonic cooling cycle. DETAILED DESCRIPTION
[041] FIGURE 3 illustrates an exemplary cooling system 300 utilizing a supersonic cooling cycle in accordance with an embodiment of the present invention. The cooling system 300 does not need to compress a gas as otherwise occurs at compressor 110 in the prior art vapor compression system 100 illustrated in FIGURE 1. Cooling system 300 operates by pumping liquid. Because cooling system 300 pumps liquid, the compression cooling system 300 does not require the use of a condenser 120 as does the prior art compression system 100. Compression cooling system 300 instead utilizes a compression wave. The evaporator of cooling system 300 operates in the critical flow regime where the pressure in an evaporator tube will remain almost constant and then 'jump' or 'shock up' to the ambient pressure.
[042] The cooling system 300 of FIGURE 3 recognizes a heightened degree of efficiency in that the pump 320 of the system 300 is not required to draw as much power as the compressor 110 in a prior art compression system 100 like that illustrated in FIGURE 1. A compression system designed according to an
embodiment of the presently disclosed invention may recognize exponential performance efficiencies. For example, a prior art compression system 100 as illustrated in FIGURE 1 may require 1.75-2.5 kilowatts to generate 5 kilowatts of cooling power. Prior art compression system 100 therefore may operate at a coefficient of performance (COP) of less than 3. A system 300 like that illustrated in FIGURE 3 may pump fluid from approximately 14.7 to approximately 120 PSI with the pump drawing power at approximately 500W (0.5 kilowatts), with the system 300 also generating 5 kilowatts of cooling power. The system 300 may therefore operate with a COP of 10. As a result of the cycle illustrated in FIGURE 3, and the resultant increased efficiencies, system 300 may utilize many working fluids, including but not limited to water.
[043] The cooling system 300 of FIGURE 3 may include a housing 310. The general shape of housing 310 of FIGURE 3 is akin to that of a pumpkin. The particular shape or other design features of housing 310 may be a matter of aesthetics and convenience with respect to where and how the system 300 is installed. The design of the housing 310 may be influenced by the facility in which the system 300 is installed, or by the equipment or machinery to which the system 300 is coupled. Functionally, housing 310 encloses pump 330, evaporator 350, and the attendant accessory equipment or flow paths (e.g., pump inlet 340 and evaporator tube 360). Housing 310 also contains the working fluid to be used by the system 300.
[044] Housing 310, in an alternative embodiment, may also encompass a secondary heat exchanger as in system 400, which is illustrated in FIGURE 4. The secondary heat exchanger is not necessarily contained within the housing 310. In such an embodiment, the outer surface area of the system 400— that is, the housing 310— may be utilized in a cooling process through forced convection on the external surface of the housing 310.
[045] Pump 330 may be powered by a motor 320, which may be external to the system 300 and which is located outside the housing 310 in FIGURE 3. Motor 320 may alternatively be contained within the housing 310 of system 300. Motor 320 may drive the pump 330 of FIGURE 3 through a rotor drive shaft with a corresponding bearing and seal or magnetic induction, whereby penetration of the housing 310 is not required. Other motor designs may be utilized with respect to motor 320 and corresponding pump 330 including synchronous, alternating (AC), and direct current (DC) motors. Other electric motors that may be used with system 300 include induction motors; brushed and brushless DC motors; stepper, linear, unipolar, and reluctance motors; and ball bearing, homopolar, piezoelectric, ultrasonic, and electrostatic motors.
[046] Pump 330 establishes circulation of a compressible working fluid through the interior fluid flow paths of system 300, the flow paths being contained within the housing 310. Pump 330 may circulate the working fluid throughout system 300 through the use of vortex flow rings. Vortex rings operate as energy reservoirs whereby added energy is stored in the vortex ring. The progressive introduction of energy to a vortex ring via pump 330 causes the corresponding ring vortex to function at a level such that energy lost through dissipation corresponds to energy being input. [047] Pump 330 operates to raise the pressure of a liquid being used by system 300 from, for example, 20 PSI to 100 PSI or more. Some systems may operate at an increased pressure of approximately 300 PSI. Other systems may operate at an increased pressure of approximately 500 PSI.
[048] Pump inlet 340 introduces a liquid to be used in cooling and otherwise resident in system 300 into pump 330. Fluid temperature may, at this point in the system 300, be approximately 95 F.
[049] The working fluid introduced to pump 330 by inlet 340 traverses a primary fluid flow path to nozzle / evaporator 350. Evaporator 350 induces a pressure drop (e.g., to approximately 5.5 PSI) and phase change that results in a low temperature. The working fluid further 'boils off at evaporator 350, whereby the resident liquid may be used as a coolant. For example, the liquid coolant may be water cooled to 35-45° F (approximately 37 ° F as illustrated in FIGURE 3).
[050] As noted above, the system 300 (specifically evaporator 350) operates in the critical flow regime, thereby generating a compression wave. The working fluid exits the evaporator 350 via evaporator tube 360 where the fluid is 'shocked up' to approximately 20 PSI because the flow in the evaporator tube 360 is in the critical regime. In some embodiments of system 300, the nozzle / evaporator 350 and evaporator tube 360 may be integrated and/or collectively referred to as an evaporator.
[051] The working fluid of system 300 (having now absorbed heat for dissipation) may be cooled at a heat exchanger to assist in dissipating absorbed heat, the temperature of the fluid being approximately 90-100° F after having exited evaporator 350. Instead of a heat exchanger, however, the housing 310 of the system 300 (as was noted above) may be used to cool via convection. FIGURE 5 illustrates an exemplary performance cycle of a cooling system utilizing a supersonic cooling cycle such as the systems illustrated in FIGURES 3 and 4. The operating steps of the method utilized in system 300 are described in further detail below with reference to FIGURE 13.
[052] FIGURE 6 illustrates the operation of an exemplary cooling system 600 that utilizes a supersonic cooling cycle. The system 600 utilizes a small pump 610, which may be of any type, and at least one evaporator or tube 620. The tube 620 may have a converging - diverging conformation. The tube 620 functions as the evaporator in the system 600. FIGURE 6 illustrates a supersonic cooling system 600 in which a single evaporator tube 620 is utilized, a configuration that may typically be implemented in installations requiring a cooling power of, for example, 300 watts. In various configurations of the system 600, more than one evaporator tube 620 may be employed (as illustrated in FIGURES 3 and 4) depending on the requirements of a given application.
[053] A heat exchanger 630 may be employed in a fluid flow path in the system 600 to remove heat from the system. When the cooling system 600 is employed as a personal cooling system, the heat exchanger 630 is utilized in the transfer of heat away from the body of the user of the system.
[054] The pump 610 raises the pressure of a fluid in the system 600. Various fluids, including water, may be used in the system. Other refrigerants such as green refrigerant R134a may also be used. The pressure of the fluid may be raised from 20 PSI to in excess of 100 PSI. The fluid flows through the tube 620 of the evaporator. Pressure drop and phase change that occur as the fluid is accelerated through the tube 620 result in a lowered temperature of the fluid in the tube 620 and provide the cooling power for the system 600.
[055] Critical flow rate, which is the maximum flow rate that can be attained by a compressible fluid as that fluid passes from a high pressure region to a low pressure region (i.e., the critical flow regime), allows for a compression wave to be established and utilized in the critical flow regime. Critical flow occurs when the velocity of the fluid is equal to or greater than the speed of sound in the fluid.
[056] In critical flow, the pressure in the channel may not be influenced by the exit pressure, and at or near the channel exit, the fluid will 'shock up' to the ambient condition. In critical flow the fluid will also stay at the low pressure and temperature corresponding to the saturation pressure.
[057] In cooling system 600, the cooled working fluid is passed through heat exchanger 630 to effectuate a heat transfer to the atmosphere. The operating steps of the method utilized in system 600 are further described below with reference to FIGURE 13.
[058] FIGURE 7 illustrates an exemplary embodiment of a cooling system 600, a personal cooling unit 700. FIGURE 7 shows a full body garment 710 used in one implementation of the personal cooling unit 700. It will be recognized by those skilled in the art that the garment chosen may cover any part of the body chosen by the user. Suitable garments for various configurations of the personal cooling unit 700 include, but are not limited to, full body garments such as overalls or jumpsuits, vests, shirts, pants, and hats. In short, any part of the body that the user desires to cool may be matched to a garment equipped with the personal cooling unit 700.
[059] The garment 710 of the cooling unit 700 includes a cooling fluid circulation path 920 (see FIGURE 9) thermally coupled to the fluid flow path of the working fluid of the supersonic cooling cycle of the unit. The cooling fluid circulation path 920 carries cooling fluid throughout the garment. As the cooling fluid flows through the cooling fluid circulation path 920, the cooling fluid is subject to warming due to ambient and body heat. In units utilizing a full body garment, warming of the fluid in the cooling fluid circulation path 920 can be a significant problem. Therefore, the cooling fluid circulation path 920 may be a manifolded capillary system to reduce the length of any given branch in the unit. Minimizing the lengths of the branches in the cooling fluid circulation path 920 reduces the possibility of the cooling fluid absorbing too much heat to properly cool the user.
[060] A control pack 720 may include a thermostat to control the temperature of the unit. The unit will typically be operated to maintain a temperature in the garment of between 12° C and 24° C. The thermostat controlled operating
temperature of the cooling unit 700 ensures a comfortable and uniform temperature throughout the unit 700. The control pack 720 may also include an on/off switch that controls the power supply to the cooling unit 700. The user may control the temperature in the cooling unit 700 by simply turning the power on and off as necessary to maintain a comfortable temperature.
[061] Heat may be vented from the cooling unit 700 via vents 730 in the surface of the control pack 720. The vents 730 may be a series of fins to increase the surface area available for heat transfer. The vents may also be holes, slots, or any other construction that would facilitate the transfer of heat.
[062] Personal cooling unit 700 may be powered by a 12 or 24 volt power supply. The personal cooling unit 700 may be powered by self-contained batteries or by a solar cell. A solar cell may also be used to charge the self-contained batteries. Those skilled in the art will recognize that many power supply configurations may be utilized in the personal cooling unit 700.
[063] As depicted in FIGURE 7 personal cooling unit 700 may have the control pack 720 mounted on the back of the user, akin to a backpack. However, the position in which the control pack 720 is mounted may vary with a given application. The mounting of the control pack 720 is a matter of choice of the user of the unit. The unit may be mounted on the user's back as shown in FIGURE 7 or on the leg as shown in FIGURE 8. The control pack 720 may be mounted at any location that is convenient for the user.
[064] FIGURE 9 illustrates a personal cooling unit 900 that utilizes a tight fitting garment 910. Garment 910 may be made from a stretchable fabric such as Spandex, Lycra, etc., to hold the cooling fluid in the cooling fluid circulation path 920 in close proximity to the body of the user.
[065] A manifolded cooling fluid supply 930 routes cooling fluid cooled by the working fluid in the fluid flow path through the cooling fluid circulation path 920. The cooling fluid circulation path 920 is thermally coupled to the fluid flow path of a supersonic cooling cycle. The cooling fluid circulation path 920 may trace, as illustrated in FIGURE 9, the main arteries of the body of the user. Positioning the cooling fluid circulation path 920 so that it traces the main arteries of the user may increase the efficiency of heat dissipation from the body of the user.
[066] Personal cooling unit 900 combines the tight fitting garment 910 with a cooling fluid circulation path 920 that traces the main arteries of the user. Users of the personal cooling unit 900 may therefore experience improved efficiency of heat removal due to the cooling unit 900 maintaining close proximity between the cooling fluid in the circulation path 920 and areas of significant heat accumulation from the body of the user, i.e. the main arteries. [067] FIGURE 10 shows an exemplary embodiment of a portable cooling unit 1000 that utilizes the supersonic cooling cycle. Portable cooling unit 1000 may be powered by a 12 volt power supply, such as a car battery. An adapter 1010 that plugs into a power outlet such as those commonly found in vehicles may be provided with the portable cooling unit 1000. Portable cooling unit 1000 may also be powered by self-contained batteries or a solar cell. A solar cell may also be used to charge the self-contained batteries. Those skilled in the art will recognize that many power supply configurations may be utilized in the portable cooling unit 1000.
[068] The housing 1020 of the cooling unit 1000 may include one or more fins 1030. The fins 1030 may be coupled to the working fluid in the portable cooling unit 1000, and may be open to the atmosphere. The fins 1030 may therefore be used as a radiator to transfer heat from the interior of the unit 1000 to the exterior atmosphere.
[069] FIGURE 11 illustrates a battery cooling system 1100 that may be utilized in conjunction with the supersonic cooling cycle as illustrated in FIGURE 4. The cooling cycle shown in FIGURE 4 may be adapted to utilize the single nozzle cycle depicted in FIGURE 6. A cooling fluid circulation path of the system 1100 routes the secondary cooling fluid through battery cooling system 1100. The battery cooling system 1100 may be used to cool high power battery packs, including but not limited to those that may be utilized in EV (electric vehicle) or HEV (hybrid electric vehicle) applications.
[070] A battery pack 1110 may be cooled by a cooling jacket 1120 in an implementation of the battery cooling system 1100 as illustrated in FIGURE 11. In this configuration, the cooling jacket 1120 surrounds the exterior of battery pack 1110. It should be noted that the cooling element, cooling jacket 1120, may accommodate whatever fluid is chosen to be used as the cooling fluid. Water and other fluids may be used as the cooling fluid in the system 1100.
[071] Cooling jacket 1120 may include either a rigid or a flexible housing. The choice of housing depends on the requirements of a given application. The cooling fluid circulation path routes the cooling fluid through the cooling jacket 1120. The cooling fluid in the circulation path removes heat from the battery pack. The cooling fluid flows into the cooling jacket 1120 through an inlet 1130, and out of the jacket 1120 through an outlet 1140.
[072] Battery cooling system 1100 may be powered from the battery pack which it is cooling, or from an independent volt power supply, typically a 12 or 24 volt power supply. If an independent power supply is utilized, the power supply may be self-contained batteries or a solar cell. A solar cell may also be used to charge self- contained batteries. Those skilled in the art will recognize that many power supply configurations may be utilized in the battery cooling system 1100.
[073] FIGURE 12 shows a battery cooling system 1200 with a battery pack that includes a plurality of battery cells 1210. In battery cooling system 1200, the cooling jacket 1220 includes a plurality of receptacles 1230. Each receptacle 1230 may receive a battery cell 1210. The cooling fluid circulation path of cooling system 1200 flows around one or more of the battery cells 1210 contained in receptacles 1230 to remove heat from the battery pack. The cooling fluid flows into the cooling jacket 1220 through an inlet 1240, and out through an outlet 1250.
[074] FIGURE 13 illustrates a method of operation 1300 for the cooling cycles utilized in the systems disclosed herein. In step 1310, a pump raises the pressure of a liquid. The pressure may, for example, be raised from 20 PSl to in excess of 100 PSL As mentioned above, the increased pressure may be 300 PSl or even 500 PSL In step 1320, fluid flows through the nozzle / evaporator tube(s). Pressure drop and phase change as the fluid accelerates through the evaporator result in a lower temperature as fluid is boiled off in step 1330.
[075] Critical flow rate, which is the maximum flow rate that can be attained by a compressible fluid as that fluid passes from a high pressure region to a low pressure region (i.e., the critical flow regime), allows for a compression wave to be established and utilized in the critical flow regime. Critical flow occurs when the velocity of the fluid is equal to or greater than the speed of sound in the fluid. In critical flow, the pressure in the channel will not be influenced by the exit pressure and at or near the channel exit, the fluid will "shock up" to the ambient condition. In critical flow the fluid will also stay at the low pressure and temperature
corresponding to the saturation pressures. In step 1340, upon the fluid exiting the evaporator tube, the fluid "shocks up" to 20 PSI. A heat exchanger may be used in optional step 1350. Cooling may also occur via convection on the surface of the housings of the cooling systems that utilize the supersonic cooling cycle.
[076] While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. The descriptions are not intended to limit the scope of the invention to the particular forms set forth herein. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments. It should be understood that the above description is illustrative and not restrictive. To the contrary, the present descriptions are intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims and otherwise appreciated by one of ordinary skill in the art. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

Claims

CLAIMS WHAT IS CLAIMED IS:
1. A personal cooling system comprising:
a garment including a cooling fluid circulation path to carry a cooling fluid throughout the garment, the circulation path being thermally coupled to a fluid flow path;
a pump that maintains a fluid flow of a working fluid through the fluid flow path, the pump also maintaining flow of the cooling fluid through the cooling fluid circulation path ;
an evaporator that operates in the critical flow regime of the working fluid and generates a compression wave that shocks the maintained fluid flow in the fluid flow path, thereby changing the pressure of the maintained fluid flow to cool the fluid;
a heat exchanging mechanism to transfer heat from the system.
2. The personal cooling system of claim 1, further comprising a control pack, the control pack including a battery to power the system.
3. The personal cooling system of claim 1, further comprising a control pack, the control pack including a thermostat to control the temperature of the system.
4. The personal cooling system of claim 1, further comprising a control pack, the control pack including a solar cell to charge the battery.
5. The personal cooling system of claim 1, further comprising a control pack, an external surface of the control pack including at least one vent.
6. The personal cooling system of claim 5, wherein the heat exchanging mechanism comprises a plurality of fins to increase the surface area of the heat exchanging mechanism.
7. The personal cooling system of claim 1, wherein a single tube is utilized in the evaporator.
8. The personal cooling system of claim 1, wherein the evaporator generates approximately 300 watts of cooling power.
9. The personal cooling system of claim 1, further comprising a manifold coupling a cooling fluid supply to the cooling fluid circulation path, the cooling fluid circulation path including one or more branches coupled to the manifold.
10. The personal cooling system of claim 1, wherein the garment is made from a stretchable fabric fitted to hold the cooling fluid circulation path in close proximity to the body of a user.
11. The personal cooling system of claim 1, wherein the cooling fluid circulation path traces major arteries of the body of a user.
12. A personal cooling system comprising:
a garment including a cooling fluid circulation path thermally coupled to a fluid flow path;
a pump that maintains a fluid flow of a working fluid through a fluid flow path and through the cooling fluid circulation path; and
an evaporator that effects a phase change in the working fluid, wherein the evaporator establishes a compression wave in the working fluid by passing the working fluid from a high pressure region to a low pressure region, the velocity of the fluid being greater than or equal to the speed of sound in the working fluid, the working fluid being cooled during a phase change, the cooled working fluid cooling the cooling fluid in the cooling fluid circulation path, thereby cooling the user of the personal cooling system.
13. The system of claim 12, wherein the garment is made from a stretchable fabric fitted to hold the cooling fluid circulation path in close proximity to the body of a user.
14. The system of claim 12, wherein the working fluid is water.
15. The system of claim 12, wherein the evaporator induces a pressure drop in the working fluid to approximately 5.5 PSI, a corresponding phase change resulting in a lowered temperature of the working fluid.
16. The system of claim 12, wherein a pressure change within the fluid flow of the working fluid occurs within a range of approximately 20 PSI to 100 PSI.
17. The system of claim 12, wherein a pressure change within the fluid flow of the working fluid involves a change to an excess of 100 PSI.
18. The system of claim 12, wherein the cooling fluid circulation path traces major arteries of the body of a user.
19. The system of claim 12, wherein the pump raises the pressure of the fluid flow from approximately 20 PSI to approximately 100 PSI.
20. The system of claim 12, wherein the pump raises the pressure of the fluid flow to more than 100 PSI.
21. A portable cooling unit comprising:
a pump that maintains a circulatory fluid flow through a flow path;
an evaporator that operates in the critical flow regime of a circulatory fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow with no heat being added to the circulatory fluid flow before the circulatory fluid flow passes through the evaporator; a heat exchanging mechanism thermally coupled to the circulatory fluid flow; and
a storage compartment, the storage compartment receiving items to be cooled or maintained at a temperature below ambient, wherein the cooling unit is readily transportable.
22. The portable cooling unit of claim 21, wherein the storage compartment forms a housing for the pump and the evaporator.
23. The portable cooling unit of claim 22, wherein at least a portion of an external surface of the storage compartment serves as the heat exchanging mechanism by effectuating convection from the interior of the unit to the atmosphere.
24. The portable cooling unit of claim 21, wherein the heat exchanging mechanism is a radiator.
25. The portable cooling unit of claim 21, wherein a single tube is utilized in the evaporator.
26. The portable cooling unit of claim 25, wherein the cooling unit generates approximately 80 watts of cooling power.
27. The portable cooling unit of claim 21, wherein the unit is battery powered.
28. The portable cooling unit of claim 27, wherein the battery is charged by a solar cell.
29. The portable cooling unit of claim 21, wherein the unit is powered by a solar cell.
30. The portable cooling unit of claim 21, wherein the pump raises the pressure of the circulatory fluid flow from approximately 20 PSl to approximately 100 PSL
31. The portable cooling unit of claim 21, wherein the pump raises the pressure of the circulatory fluid flow to more than 100 PSL
32. A portable cooling system comprising:
a storage compartment, the storage compartment receiving items to be cooled or maintained at a temperature below ambient;
a pump that maintains a fluid flow of a fluid through the system; and an evaporator that effects a phase change in the fluid, wherein the system establishes a compression wave in the fluid by passing the fluid from a high pressure region to a low pressure region, the velocity of the fluid being greater than or equal to the speed of sound in the fluid, the fluid being cooled during a phase change so that heat is transferred from the system by thermally coupling one or more fins between the fluid and the ambient atmosphere, and wherein the cooling unit is readily transportable.
33. The system of claim 32, further comprising a pump inlet that introduces a cooling liquid maintained within the housing to the pump, and wherein the cooling liquid is a part of the circulatory fluid flow.
34. The system of claim 32, wherein the evaporator induces a pressure drop in the cooling liquid to approximately 5.5 PSI, a corresponding phase change resulting in a lowered temperature of the cooling liquid.
35. The system of claim 33, wherein the cooling liquid is water.
36. The system of claim 32, wherein a pressure change within a fluid flow of the fluid occurs within a range of approximately 20 PSI to 100 PSI.
37. The system of claim 32, wherein a pressure change within a fluid flow of the fluid involves a change to an excess of 100 PSI.
38. The system of claim 32, wherein a pressure change within a fluid flow of the fluid involves a change to less than 20 PSI.
39. The system of claim 32, wherein the pump raises the pressure of the circulatory fluid flow from approximately 20 PSI to approximately 100 PSI.
40. The system of claim 32, wherein the pump raises the pressure of the circulatory fluid flow to more than 100 PSI.
41. A battery cooling system comprising:
a cooling fluid circulation path thermally coupled to a working fluid flow path and to at least one battery cell in a battery pack;
a pump that maintains a fluid flow through the working fluid flow path; an evaporator that operates in the critical flow regime of the working fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow to cool the fluid; and
a heat exchanging mechanism thermally coupled to the fluid flow path, the heat exchanging mechanism removing heat from the battery pack.
42. The battery cooling system of claim 41, further comprising a cooling jacket, the cooling jacket being thermally coupled the working fluid flow path and to at least a portion of the battery pack.
43. The battery cooling system of claim 42, wherein the cooling jacket includes a plurality of receptacles, each receptacle receiving a cell of the battery pack.
44. The battery cooling system of claim 42, wherein the cooling jacket surrounds the battery pack.
45. The battery cooling system of claim 42, wherein the cooling jacket comprises a rigid housing.
46. The battery cooling system of claim 42, wherein the cooling jacket comprises a flexible housing.
47. The battery cooling system of claim 41, wherein the heat exchanging mechanism comprises a plurality of fins to increase the surface area of the heat exchanging mechanism.
48. The battery cooling system of claim 41, wherein a single tube is utilized in the evaporator.
49. The battery cooling system of claim 41, wherein the pump raises the pressure of the fluid flow from approximately 20 PSI to approximately 100 PSI.
50. The battery cooling system of claim 41, wherein the pump raises the pressure of the fluid flow to more than 100 PSI.
51. A battery cooling system comprising:
a fluid flow path that passes in close proximity to at least one battery cell in a battery pack;
a pump that maintains a fluid flow through the fluid flow path;
at least one evaporator that operates in the critical flow regime of the fluid and generates a compression wave that shocks the maintained fluid flow, thereby changing the pressure of the maintained fluid flow to cool the fluid, the cooled fluid removing heat from the battery cell via conduction.
52. The system of claim 51, wherein the at least one evaporator comprises a series of single tube evaporators aligned in parallel with a plurality of battery cells, each single tube evaporator removing heat from the aligned battery cell.
53. The system of claim 51, further comprising a pump inlet that introduces a cooling liquid to the pump, and wherein the cooling liquid is a part of the fluid flow.
54. The system of claim 53, wherein the cooling liquid is water.
55. The system of claim 53, wherein the evaporator induces a pressure drop in the cooling liquid to approximately 5.5 PSI, a corresponding phase change resulting in a lowered temperature of the cooling liquid.
56. The system of claim 53, wherein a pressure change within the fluid flow of the fluid occurs within a range of approximately 20 PSI to 100 PSI.
57. The system of claim 53, wherein a pressure change within the fluid flow of the fluid involves a change to an excess of 100 PSI.
58. The system of claim 53, wherein a pressure change within the fluid flow of the fluid involves a change to less than 20 PSI.
59. The system of claim 53, wherein the pump raises the pressure of the fluid flow from approximately 20 PSI to approximately 100 PSI.
60. The system of claim 53, wherein the pump raises the pressure of the fluid flow to more than 100 PSI.
PCT/US2011/027845 2010-03-25 2011-03-10 Cooling systems utilizing a supersonic cooling cycle WO2011119338A1 (en)

Applications Claiming Priority (12)

Application Number Priority Date Filing Date Title
US12/732,171 US8333080B2 (en) 2009-03-25 2010-03-25 Supersonic cooling system
US12/732,171 2010-03-25
US12/880,940 US20110048062A1 (en) 2009-03-25 2010-09-13 Portable Cooling Unit
US12/880,940 2010-09-13
US38464910P 2010-09-20 2010-09-20
US38465310P 2010-09-20 2010-09-20
US61/384,653 2010-09-20
US61/384,649 2010-09-20
US12/902,060 US20110048048A1 (en) 2009-03-25 2010-10-11 Personal Cooling System
US12/902,056 US8505322B2 (en) 2009-03-25 2010-10-11 Battery cooling
US12/902,056 2010-10-11
US12/902,060 2010-10-11

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