Source: https://patents.justia.com/patent/8474255
Timestamp: 2019-09-20 14:07:34
Document Index: 683450949

Matched Legal Cases: ['Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61']

US Patent for Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange Patent (Patent # 8,474,255 issued July 2, 2013) - Justia Patents Search
Justia Patents Fluid Mingling (e.g., Condensation)US Patent for Forming liquid sprays in compressed-gas energy storage systems for effective heat exchange Patent (Patent # 8,474,255)
May 12, 2011 - SustainX, Inc.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/334,722, filed May 14, 2010, U.S. Provisional Patent Application No. 61/349,009, filed May 27, 2010, U.S. Provisional Patent Application No. 61/363,072, filed Jul. 9, 2010, and U.S. Provisional Patent Application No. 61/393,725, filed Oct. 15, 2010, and is a continuation-in-part of U.S. patent application Ser. No. 12/639,703, filed Dec. 16, 2009, which (i) is a continuation-in-part of U.S. patent application Ser. No. 12/421,057, filed Apr. 9, 2009, which claims the benefit of and priority to U.S. Provisional Patent Application No. 61/148,691, filed Jan. 30, 2009, and U.S. Provisional Patent Application No. 61/043,630, filed Apr. 9, 2008; (ii) is a continuation-in-part of U.S. patent application Ser. No. 12/481,235, filed Jun. 9, 2009, which claims the benefit of and priority to U.S. Provisional Patent Application No. 61/059,964, filed Jun. 9, 2008; and (iii) claims the benefit of and priority to U.S. Provisional Patent Application Nos. 61/166,448, filed on Apr. 3, 2009; 61/184,166, filed on Jun. 4, 2009; 61/223,564, filed on Jul. 7, 2009; 61/227,222, filed on Jul. 21, 2009; and 61/251,965, filed on Oct. 15, 2009. The entire disclosure of each of these applications is hereby incorporated herein by reference.
The mass m of heat-exchange liquid entering the cylinder chamber in a given time interval is given by flow rate q and fluid density p. Here, m has units of kg, q has units of m3/s, and p has units of kg/m3. Thus, to add or remove more heat from the gas in the cylinder chamber for a heat-exchange liquid with near-constant density p, the flow rate q of the heat-exchange liquid is increased.
When liquid flows through a nozzle or orifice, it encounters resistance. This resistance is associated with a pressure drop Δp from the input side of the nozzle to the output side. The pressure drop across (i.e., through) the nozzle depends on the characteristics of a particular nozzle, including its shape, and on the flow rate q. In particular, to increase flow rate q, the pressure drop Δp is increased. The relationship between flow rate q and pressure drop Δp has the general form q∝pn; n is typically less than 0.50. (This may also be expressed as p∝q1/n) Moreover, the spraying power P consumed by forcing liquid at rate q through a nozzle with a constant pressure drop Δp is P=Δp q. Substituting Δp∝q1/n for Δp in P=Δp q gives P∝q q1/n=q1/n+1. If, for example, n=0.5, then P∝q1/n+1=q1/0.5+1=q3. Thus, the power required to achieve a given amount of flow through a single nozzle—and therefore through any fixed number of nozzles—increases geometrically with flow rate. As a consequence, doubling the flow rate more than doubles the required spraying power.
The rate of heat transfer between the gas in the pneumatic cylinder chamber and the heat-exchange liquid spray is proportional to the flow rate and bears a similar relation to spraying power as does the flow rate. Specifically, from Q=m c ΔT we have dQ/dt=p q c ΔT, where t is time, p is liquid density, q is liquid flow rate, ΔT is the difference between the initial temperature of the liquid and the final temperature of the liquid, and dQ/dt is rate of heat transfer. If p, c and ΔT are constant, dQ/dt∝q. In the example where n=0.5, one has P∝q3, which combined with dQ/dt∝q gives P∝(dQ/dt)3. The spraying power P is thus, for an exemplary n of 0.5, proportional to the third power of the required rate of heat transfer. This result holds for any fixed number of nozzles.
The principle may be extended to more than two cylinders to suit particular applications. For example, a narrower output force range for a given range of reservoir pressures is achieved by having a first, high-pressure cylinder operating between, for example, approximately 3,000 psig and approximately 300 psig and a second, larger-volume, lower-pressure cylinder operating between, for example, approximately 300 psig and approximately 30 psig. When two expansion cylinders are used, the range of pressure within either cylinder (and thus the range of force produced by either cylinder) is reduced as the square root relative to the range of pressure (or force) experienced with a single expansion cylinder, e.g., from approximately 100:1 to approximately 10:1 (as set forth in the '853 application). Furthermore, as set forth in the '595 application, N appropriately sized cylinders can reduce an original operating pressure range R to R1/N Any group of N cylinders staged in this manner, where N≧2, is herein termed a cylinder group.
These and other objects, along with advantages and features of the invention, will become more apparent through reference to the following description, the accompanying drawings, and the claims. Furthermore, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations. Note that as used herein, the terms “pipe,” “piping” and the like shall refer to one or more conduits that are rated to carry gas or liquid between two points. Thus, the singular term should be taken to include a plurality of parallel conduits where appropriate. Herein, the terms “liquid” and “water” interchangeably connote any mostly or substantially incompressible liquid, the terms “gas” and “air” are used interchangeably, and the term “fluid” may refer to a liquid or a gas unless otherwise indicated. As used herein unless otherwise indicated, the term “substantially” means ±10%, and, in some embodiments, ±5%. A “valve” is any mechanism or component for controlling fluid communication between fluid paths or reservoirs, or for selectively permitting control or venting. The term “cylinder” refers to a chamber, of uniform but not necessarily circular cross-section, which may contain a slidably disposed piston or other mechanism that separates the fluid on one side of the chamber from that on the other, preventing fluid movement from one side of the chamber to the other while allowing the transfer of force/pressure from one side of the chamber to the next or to a mechanism outside the chamber. In the absence of a mechanical separation mechanism, a “chamber” or “compartment” of a cylinder may correspond to substantially the entire volume of the cylinder. A “cylinder assembly” may be a simple cylinder or include multiple cylinders, and may or may not have additional associated components (such as mechanical linkages among the cylinders). The shaft of a cylinder may be coupled hydraulically or mechanically to a mechanical load (e.g., a hydraulic motor/pump or a crankshaft) that is in turn coupled to an electrical load (e.g., rotary or linear electric motor/generator attached to power electronics and/or directly to the grid or other loads), as described in the '595 and '853 applications.
The energy required to inject the liquid into the gas is the energy required to force water through the spray mechanism 134. In general, for a given liquid flow rate (e.g., gallons per minute) through each orifice, larger orifices in the spray mechanism 134 will entail a smaller liquid pressure drop (ΔP) from the interior of the spray mechanism 134 to the interior of chamber 114 and therefore less expenditure of energy (Ei) to inject a given volume (VT) of heat-transfer liquid: Ei=VT×ΔP.
Under conditions where a jet is produced at the orifice outlet, three basic types or regimes of liquid phase breakup and their relationship to liquid properties have been defined in W. Ohnesorge, “Formation of drops by nozzles and the breakup of liquid jets,” Zeitschrift für Angewandte Mathematik and Mechanik [Applied Mathematics and Mechanics], vol. 16, pp. 355-358 (1936) (the “Ohnesorge reference”), the entire disclosure of which is incorporated by reference herein. In a first regime 200 shown in FIG. 2, a liquid jet eventually breaks up into large droplets. In a second regime 210, a jet breaks up into droplets and rapidly changing vermiform bodies termed ligaments. In a third regime 220, the liquid atomizes quickly after exiting the orifice, i.e., forms a spray consisting of a large number of small droplets.
FIG. 3 is a chart adapted from the Ohnesorge reference. In this chart, the three breakup regimes (labeled Droplet, Wave & Droplet, and Spray) are shown as functions of two dimensionless numbers, namely the Reynolds number (horizontal axis) and the Ohnesorge number (vertical axis). The Reynolds numbers (Re) is a function of the liquid velocity at exit from the hole (v), hole diameter (D), liquid density (ρ), and liquid dynamic viscosity (μ): Re=ρvD/μ. The Ohnesorge number (Oh) is a function of hole diameter (D), liquid density (ρ), liquid dynamic viscosity (μ), and liquid surface tension (σ): Oh=μ/(σρD)1/2. For a particular case of liquid flow from an orifice, the ratio of Re to Oh generally determines the type of breakup that will occur. For a liquid (e.g., water) having a fixed dynamic viscosity, density, and surface tension, a flow's Ohnesorge number (vertical coordinate on the chart) is determined by orifice diameter and its Reynolds number (horizontal coordinate) is determined by jet velocity. In FIG. 3, a line 300 denotes the transition from the Spray regime to the Wave & Droplet regime; another line 302 denotes the transition from the Wave & Droplet regime to the Droplet regime.
The chart shown in FIG. 3 is generally valid for liquid injection into gas at atmospheric pressure. At higher gas pressures, the aerodynamic forces acting on a jet of a given size are greater and atomization therefore occurs at lower velocities (lower Reynolds number, Re). FIG. 4 is a variation of the chart shown in FIG. 3 modified to reflect higher gas pressure. Five atomization operating points are denoted by dots 400 placed on the line 300 that in FIG. 3 corresponds to the boundary between spray (atomization) breakup and wave-and-droplet breakup at atmospheric pressure. For an air pressure of approximately 3,000 psig, atomization tends to occur at lower jet velocities than at atmospheric pressure. Since Reynolds number Re is proportional to velocity, the boundary line between wave-and-droplet breakup and spray breakup is effectively shifted to the left (i.e., to lower Reynolds numbers) by increased air pressure. This shifted boundary is indicated by a dashed line 404. In this illustrative example, raising the air pressure to approximately 3,000 psig has the effect of shifting the five operating points 400 leftward to new locations 402 on the dashed boundary line 404. That is, all other parameters being held equal, a jet will typically atomize at lower velocity in approximately-3,000-psig air. Lower jet velocity corresponds to lower pressure drop ΔP through each spray-head orifice and, therefore, to lower injection energy Ei. Dashed boundary line 404 corresponds to Weber number for air (herein denoted Weair)≧40. The Weber number of air Weair is a function of hole diameter (D), air density (ρair), liquid injection velocity (v), and liquid surface tension (σ): Weair=ρairv2D/σ.
Furthermore, having specified the hole diameter and flow velocity in the first and third columns, and having knowledge of the specific heat of water, one may use the total flow per kW of per degree Celsius (heat-transfer coefficient) and an assumed temperature change of the injected fluid (here 5° C.) to calculate the number of orifices needed: this number is provided here in the fifth column of FIG. 5.
FIG. 6 is a graph of calculated water spray heat-transfer rate limits for a range of water droplet sizes (25 μm-900 μm) for two extremes of water breakup behavior, namely solid jet and atomized spray, in air at 3,000 psig and at 300 psig. The horizontal axis is jet or droplet size. The vertical axis is kilowatts per GPM per degree C. change in the temperature of the injected water (kW/GPM/° C.). The upper curves 600, 610 denote kW/GPM/° C. for fully atomized injection (i.e., all injected water forms droplets falling at their terminal velocity) at 300 psig and 3,000 psig respectively, and correspond to highly efficient heat transfer. The lower curves 620, 630 denote kW/GPM/° C. for jet-only injection (i.e., no droplet breakup, and the jets propagating at 9.1 m/s injection velocity) at 300 psig and 3,000 psig respectively, and correspond to minimally efficient heat transfer. Due to non-idealities, real-world heat transfer will typically occur along some curve between these two sets of extremes.
From the values in the sixth column of FIG. 5, increasing orifice size tends to require less injection energy; however, from the drop-off of the upper curves 600, 610 in FIG. 6, maximal heat transfer (kW/GPM/° C.) tends to decline with increasing orifice size. Total efficiency therefore generally may not be increased simply by using very large orifice sizes. On the other hand, small orifices are more likely to be clogged by particles entrained in the liquid flow.
In the state of operation shown in FIG. 22A, chamber 2215 contains a quantity of gas undergoing compression. Valve 2265 is closed and valve 2260 is open. Heat-exchange liquid flows through pipe 2240, into manifold 2245, and then into the four spray nozzles 2230 of Nozzle Set 1. The heat-exchange liquid issues from Nozzle Set 1as a spray 2270 that thermally conditions (i.e., exchanges heat with) the gas in chamber 2215. Little or no spray issues from the four spray nozzles 2235 of Nozzle Set 2. Thus, Nozzle Set 1 is “active” and Nozzle Set 2 is not.
The system 2300 in FIG. 23 generally resembles the system 100 in FIG. 1 except for the means by which heat-exchange spray 2305 (136 in FIG. 1) is produced in an upper chamber 2310 of a cylinder 2315. System 2300 operates in accordance with embodiments of the invention described above with relation to FIGS. 22A and 22B. The operation of the cylinder 2315 in FIG. 23 may be identical to that of cylinder 2205 depicted in FIGS. 22A and 22B. In FIG. 23, valve 2320 is open and valve 2325 is closed. Valves 2320, 2325 enable heat-exchange liquid to pass through pipes 2330 and/or 2335 into at least one of the two sets of spray nozzles incorporated into spray head 2340 (which may also share any number of features with spray heads 900 and/or 1600 described above). In other embodiments, a spray rod or other contrivance for mounting the spray nozzles is employed. Heat-exchange liquid 2345 issues from Nozzle Set 1 in spray head 2340 as spray 2305 that may accumulate on the upper surface of a piston 2350. A center-drilled channel 2355 in a rod 2360 enables the heat-exchange liquid 2345 to be withdrawn through a flexible hose 2365 and through a pipe 2370 to 2a pump 2375 (which may be similar or identical to pump 124 described above with reference to FIG. 1). In other embodiments, alternate techniques of conducting the heat-exchange liquid 2345 to pump 2370 are employed, such as internal piping as described in U.S. Provisional Patent Application No. 61/384,814, filed Sep. 21, 2010, the entire disclosure of which is incorporated by reference herein. Exiting the pump 2375, the heat-exchange liquid is preferably conveyed by a pipe 2380 to a heat exchanger 2385 where its temperature may be altered (e.g., to maintain the heat-exchange liquid at a substantially constant desired temperature as it enters cylinder 2315). Exiting the heat exchanger 2385, the heat-exchange liquid enters pipes 2330 and 2335. In the state of operation depicted in FIG. 23, liquid is prevented from flowing through pipe 2335 because valve 2325 is closed. In another state of operation (not shown), valves 2320 and 2325 are both open and spray head 2340 produces spray from multiple sets of nozzles, e.g., in the manner depicted for spray head 2225 in FIG. 22B. It will be clear to any person familiar with the art of pneumatic and hydraulic cylinders that system 2300 may be operated in reverse, that is, to expand gas rather than compress it.
a cylinder assembly comprising a first pneumatic chamber for compressing gas to store energy and expanding gas to recover energy and a second pneumatic chamber, separated from the first pneumatic chamber;
selectively fluidly connected to the first chamber, (i) a compressed-gas reservoir for storage of gas after compression and supply of compressed gas for expansion thereof, and (ii) a vent for exhausting expanded gas to atmosphere and supply of gas for compression thereof;
a spray mechanism for introducing heat-transfer fluid within the first chamber of the cylinder assembly to exchange heat with gas therein, thereby increasing efficiency of the energy storage and recovery, the spray mechanism comprising a plurality of nozzles for collectively producing an aggregate spray filling substantially an entire volume of the first chamber; and
a circulation apparatus for circulating the heat-transfer fluid to the spray mechanism,
wherein the aggregate spray comprises a plurality of overlapping individual sprays each produced by one of the plurality of nozzles.
2. The system of claim 1, wherein each individual spray is an atomized spray of individual droplets.
3. The system of claim 2, wherein the individual droplets have an average diameter ranging from approximately 0.2 mm to approximately 1 mm.
4. The system of claim 1, wherein the plurality of nozzles maintains a Weber value of gas within the chamber of at least 40.
5. The system of claim 1, wherein each nozzle maintains a pressure drop thereacross of less than approximately 50 psi.
6. The system of claim 1, wherein at least one nozzle has a divergent cross-sectional profile.
7. The system of claim 1, wherein at least one nozzle comprises a mechanism for breaking up a flow of heat-transfer fluid therethrough.
8. The system of claim 7, wherein the mechanism comprises at least one of a plurality of vanes or a corkscrew.
9. The system of claim 1, wherein the spray mechanism comprises an interior channel for transmitting heat-transfer fluid from a source external to the cylinder assembly to the plurality of nozzles.
10. The system of claim 1, further comprising, connected to the cylinder assembly, an intermittent renewable energy source of wind or solar energy, wherein (i) energy stored during compression of gas originates from the intermittent renewable energy source, and (ii) energy is recovered via expansion of gas when the intermittent renewable energy source is nonfunctional.
11. The system of claim 1, wherein the spray mechanism comprises at least one of a spray head or a spray rod.
12. The system of claim 1, further comprising a heat exchanger for maintaining the heat-transfer fluid at a substantially constant temperature, wherein the circulation apparatus circulates heat-transfer fluid from the cylinder assembly through the heat exchanger and back to the cylinder assembly.
13. A compressed-gas energy storage and recovery system comprising:
a cylinder assembly comprising a chamber for compressing gas to store energy and expanding gas to recover energy;
selectively fluidly connected to the chamber, (i) a compressed-gas reservoir for storage of gas after compression and supply of compressed gas for expansion thereof, and (ii) a vent for exhausting expanded gas to atmosphere and supply of gas for compression thereof;
a spray mechanism for introducing heat-transfer fluid within the chamber of the cylinder assembly to exchange heat with gas therein, thereby increasing efficiency of the energy storage and recovery, the spray mechanism comprising a plurality of nozzles for collectively producing an aggregate spray filling substantially an entire volume of the chamber;
a control system for controlling the introduction of heat-transfer fluid into the chamber such that the compression and expansion of gas is substantially isothermal; and
14. The system of claim 1, wherein the plurality of nozzles is organized into at least two nozzle groups, at least one nozzle group not being active during a portion of a single cycle of compression or expansion.
a movable piston separating the first chamber from the second chamber within the cylinder assembly; and
a piston rod connected to the movable piston,
wherein the piston and piston rod define a fluid passageway selectively fluidly connected to the circulation apparatus.
16. The system of claim 1, further comprising a reservoir of heat-transfer fluid fluidly connected to the circulation apparatus, the reservoir of heat-transfer fluid containing an additive reducing surface tension of the heat-transfer fluid.
17. The system of claim 1, further comprising a control system for controlling the introduction of heat-transfer fluid into the first chamber such that the compression and expansion of gas is substantially isothermal.
18. The system of claim 13, wherein the chamber is a pneumatic chamber separated from a hydraulic chamber in the cylinder assembly.
19. The system of claim 1, wherein the spray mechanism occupies approximately an entire top surface of the first chamber.
20. A compressed-gas energy storage and recovery system comprising:
a cylinder assembly comprising a first chamber for compressing gas to store energy and expanding gas to recover energy and a second chamber;
a spray mechanism for introducing heat-transfer fluid within the first chamber and second chamber of the cylinder assembly to exchange heat with gas therein, thereby increasing efficiency of the energy storage and recovery, the spray mechanism comprising a plurality of nozzles disposed in the first chamber and second chamber for collectively producing an aggregate spray filling substantially an entire volume of the chambers; and
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Patent Publication Number: 20110314803
Inventors: Troy O. McBride (Norwich, VT), Alexander Bell (Hanover, NH), Benjamin R. Bollinger (Windsor, VT), Andrew Shang (Lebanon, NH), David Chmiel (West Lebanon, NH), Horst Richter (Norwich, VT), Patrick Magari (Plainfield, NH), Benjamin Cameron (Hanover, NH)
Application Number: 13/105,986
Current U.S. Class: Fluid Mingling (e.g., Condensation) (60/511); Having Means Within The Working Chamber To Effect The Pressure Of Fluid Therein (60/512); Convertible Motor-pump Device Selectively Charges And Is Driven By Gas From Storage Vessel (60/408); Stroke Device Driven By Successively Operated Energy Input Structure And Stored Energy Structure (60/417)
International Classification: F01K 21/04 (20060101); F01B 29/00 (20060101); F16D 31/02 (20060101);