Systems and methods of thermal transfer and/or storage
09671171 ยท 2017-06-06
Assignee
Inventors
Cpc classification
Y02E60/14
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F24H7/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24S10/95
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28C3/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D20/028
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F25/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D2020/0047
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F24D2220/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D20/0056
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D15/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D2020/006
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D2020/0021
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F2265/14
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F25D11/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D13/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25D17/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D17/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D20/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28D15/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
C09K5/06
CHEMISTRY; METALLURGY
F24H7/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28C3/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
Systems, methods, and computer-implemented embodiments consistent with the inventions herein are directed to storing and/or transferring heat. In one exemplary implementation, there is provided a system for transferring/storing heat comprised of a heat exchange/storage apparatus including a chamber, and a heat input device adapted to heat/provide a vapor into the chamber. Other exemplary implementations may include one or more features consistent with a heat output device through which a working medium/fluid passes, a thermal storage medium located within the chamber, and/or a heat exchange system that delivers a heat exchange medium/fluid to the thermal storage medium.
Claims
1. A system comprising: a heat exchange/storage apparatus including: a chamber; a heat input device that contains and introduces a heat transfer fluid HTF into the chamber where a surface of said input device in said chamber is in contact with a liquid-gas phase change heat exchange material disposed in a lower portion of said chamber; a thermal storage medium disposed within said chamber and having defined thermal storage surfaces where the thermal storage medium includes a solid-to-liquid phase change material (PCM) contained within a plurality of secondary containers wherein the PCM has a transition temperature within a temperature range such that the liquid-gas heat exchange material in vapor form external to said secondary containers condenses into liquid upon contact with said secondary containers to release latent heat into said solid-to-liquid phase change material; a heat output device associated with the chamber, wherein the heat output device contains a working fluid (WF) and includes heat output device surfaces within an upper portion of the chamber; a circulation plumbing system disposed to during a charging cycle, deliver a vapor form of said heat transfer fluid HTF into said input device, and transfer heat from said input device into a liquid form of said heat exchange material converting said heat exchange material from a liquid to a vapor which condenses on the plurality of secondary containers and transfers heat into said thermal storage medium and in doing so converts back into a liquid form; and during a discharging cycle, pass a liquid form of said heat exchange material from the lower portion of said chamber outside said chamber and then back into an upper portion of said chamber and via a showerhead or dripping device to deliver said liquid heat exchange material to a surface of said thermal storage medium to convert said heat exchange material to a vapor that rises in said chamber and contacts and condenses on a surface of said heat output device transferring heat to said working fluid in said heat output device, and then falling back down in said chamber to be heated again by said phase change material or cycled again outside said chamber; and a control system that controls pressure in the chamber.
2. The system of claim 1 wherein the heat input device includes heat input device surfaces that pass through and are exposed within the chamber.
3. The system of claim 1 wherein the heat input device surfaces are immersed within a liquid form of said heat exchange medium that transforms to vapor form upon receipt of the latent heat from the HIT in said heat input device.
4. The system of claim 3 wherein the heat input device surfaces comprise tubing.
5. The system of claim 1, wherein said heat output device is configured to transfer heat from a vapor form of said liquid-gas heat exchange material to said working fluid.
6. The system of claim 1, wherein heat charging and discharging of the thermal storage device from the heat input device and to the heat output device, respectively, is provided via time sequence control of condensation temperature and heat transfer rate via regulation of chamber pressure.
7. The system of claim 1, wherein said heat input device has an input entry for residual/exhaust heat vapor from a heat appliance and an outlet that returns the liquid condensate of said exhaust vapor to the heat appliance; said a heat output device is in thermal communication with a thermal environment to which heat can be transferred; and said control system controls pressure and heat transfer between the vapor, the thermal storage device and/or the heat output device.
8. The system of claim 7 wherein the system is configured to release the latent heat within the chamber at a desired temperature via pressure regulated by the control system.
9. The system of claim 1 wherein the chamber includes thermal insulation, and/or wherein the heat exchange/storage apparatus is configured to store the heat within the thermal storage material over an extended timeframe, for later use via exchange to the heat output device.
10. The system of claim 1 wherein the heat output device includes an entry and an outlet to circulate a working medium into contact with heat output device surfaces within the chamber, and wherein the heat output device is configured such that the latent heat is delivered to the working fluid via condensation of a vapor form of said heat exchange material on the heat output device surfaces.
11. The system of claim 1 wherein the heat exchange/storage apparatus is configured to transfer latent heat from a vapor form of said heat exchange medium produced by heat transfer from said storage medium to a liquid form of said heat exchange material to the working fluid by condensation of said heat exchange medium on the heat output device heat surfaces.
12. The system of claim 1 wherein the heat input device includes heat input device surfaces, tubing, or pipes that pass through and are exposed within the chamber.
13. The system of claim 12 wherein the heat input device surfaces are immersed within said heat exchange medium that transforms to vapor form upon receipt of the latent heat from said heat transfer fluid in said heat input device.
14. The system of claim 1 wherein the control system includes an evacuation system and inert gas pressure regulator coupled to the chamber to control pressure in the chamber.
15. The system of claim 1 wherein the condensation temperature of said heat exchange material is within a range of the thermal storage materials' phase transition temperature at a controlled chamber pressure.
16. The system of claim 1 wherein the control system controls heat transfer rates and/or temperatures between one or more of the heat input device, the thermal storage material, and/or the heat output device.
17. The system of claim 1 wherein the control system controls the temperature in the chamber using an evacuation system and an inert gas pressure regulator in conjunction with flow rate control to maintain a chamber vapor pressure and a chamber temperature for a target liquid phase volume for constant heat exchange.
18. The system of claim 1 wherein the control system controls the pressure of the chamber to cause the exhaust vapor to condense instantly at a desired temperature range and thereby transfer its latent heat to the thermal storage material.
19. The system of claim 1 wherein the control system controls the condensation temperature of the heat exchange material to be higher than the transition temperature of the thermal storage material, causing a vapor form of the heat exchange material to condense and transfer its latent heat to the thermal storage material.
20. The system of claim 1 wherein the control system controls the condensation temperature of the heat exchange material to be lower than the transition temperature of the thermal storage material, causing the heat exchange medium vapor to condense on surfaces of the heat output device and thereby transfer latent heat from the heat storage material to the working medium.
21. The system of claim 1 further comprising a circulation pump in heat exchange fluid communication with the bottom of the chamber, configured to circulate heat exchange material condensed at the bottom of the chamber.
22. The system of claim 1 wherein the control system regulates a pressure to control a temperature and heat transfer rate between the heat input device, the thermal storage material, and the heat output device in time sequence.
23. The system of claim 1, wherein the PCM material includes a low temperature phase change material having a melting point below about 100 C.
24. The system of claim 1, wherein the PCM material comprises an organic material.
25. The system of claim 1, wherein the PCM material includes a medium temperature phase change material having a melting point between about 100 C. and about 200 C.
26. The system of claim 1, wherein the PCM material includes a high temperature phase change material having a melting point above about 200 C.
27. A method of exchanging/storing heat, comprising: obtaining a vapor form of a heat transfer fluid (HTF) from the heat output of a heat source or solar collector; introducing said HTF into the heat input device of a system according to any one of claims 1-3, 4, 5, 6-8, 9, 10, 11, 12, 13, 14-22, 23, 24, 25, and 26; and operating said system to store heat from said HTF and return a liquid form of said heat transfer fluid; and/or operating said system to return heat to said working fluid.
28. The method of claim 27 wherein the step of obtaining a vapor further comprises: receiving waste heat from a heat appliance, wherein the waste heat comprises a low temperature vapor at less than 100 C. and at less than 1 atmosphere; and transferring the waste latent heat into the latent heat of solid-liquid latent of PCM storage material.
29. The method of claim 27, wherein said method comprises: discharging latent heat from the thermal storage material by evaporating said heat exchange medium and condensing said heat exchange medium on a surface of said heat output device.
30. The method of claim 27 wherein the storing/charging of latent heat into the thermal storage material is performed sequentially into a series of heat storage chambers, each having its own respective thermal storage material.
Description
DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which constitute a part of this specification, illustrate various implementations and aspects of the present invention and, together with the description, explain the principles of the invention. In the drawings:
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DETAILED DESCRIPTION
(15) Reference will now be made in detail to the invention, examples of which are illustrated in the accompanying drawings. The implementations set forth in the following description do not represent all implementations consistent with the claimed invention. Instead, they are merely some examples consistent with certain aspects related to the invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
(16) Aspects of the innovations, such as those set forth in some of the implementations below, may relate to systems and methods of integrating an evaporation-condensation heat exchange mechanism with a phase change latent heat energy storage apparatus, using liquid-gas phase change materials as heat exchange media and solid-liquid phase change materials as thermal energy storage media. However, it should be understood that the inventions herein are not limited to any such specific illustrations, but are defined by the scope of the claims and full disclosure.
(17) According to some exemplary implementations, a PCM heat exchange and thermal storage apparatus may comprise the following components: a main container, an input heat transfer device which transports HTF and its heat into the container, an output heat transfer device which transports working medium and its thermal energy out of the container, at least one type solid-liquid PCM packaged inside secondary containers acting as thermal storage medium, a liquid-gas PCM, contained by the main container, acting as heat exchange medium between surfaces that confine the HTF, storage medium and working medium, a circulating system for liquid-gas PCM, and a pressure regulating system to control the vapor pressure of liquid-gas PCM.
(18) A working medium absorbs most energy at its evaporation temperature. This is due to large amount of heat absorbed at liquid to gas phase transition or in the case of near critical point, where all liquid turns into gas phase regardless of the pressure. As the consequence, sensible heat storage medium has to provide all needed thermal energy at this temperature. In order to do this, sensible heat storage medium needed to be charged to a much higher temperature according to the Eq. 1. Since the thermal energy required for a given mass of working medium evaporates at its phase change temperature is about a few tens to a hundred times higher than the specific heat capacity of the sensible heat storage materials, T.sub.2 has to be a few hundred degree higher than the phase transition temperature of the working medium, or the mass of sensible thermal storage materials and HTF flow rate have to be hundreds time higher than the mass and the flow rate of working medium, which will increase cost. This requirement presents many challenges to the sensible thermal storage system: (1) drastically increased heat loss in solar collecting field, including solar collector, transfer pipes and storage container due to thermal radiation and convection thermal loss at unnecessarily high temperature, and difficult to control to a tolerable level; (2) it requires the HTF work at this unnecessarily high temperature. Usually the tolerable working temperature of HTF limits the T.sub.2 and in turn limits the working temperature of the working medium. Low working temperature of the working medium will result a low efficiency of the heat engine. Latent heat storage matches the heat demand of working medium near working temperature, lowers the required working temperature of HTF and solar collectors, therefore heat loss; and improves the efficiency of the heat engine.
(19) To match the large thermal energy demand near the working (i.e, phase transition) temperature of the working medium, it is desirable to have a phase change material with transition temperature at or slightly above the working temperature as the thermal storage medium, which has a large latent heat absorbed or released at the phase transition to match demand. Furthermore, to provide storage medium of such large amount of heat, it is also desirable to have the HTF be a phase change materials (i.e. vapor-liquid phase change material, and transfer between heat source and heat storage/exchange apparatus as a vapor form carrying large latent heat and delivering upon condensation), as explained below, otherwise the HTF must have a very large flow rate (much larger than the flow rate of working medium) or a very high working temperature.
(20) Liquids with large temperature span, such as water, synthetic oils, ionic fluids, etc., may be used as the HTF for thermal energy input. Working fluids (WFs), which may be water, though can also be ammonia, organic solutions, and many other choices of liquid with desired properties, are typically used for thermal energy output. Examples of such fluid are set forth in Table 1. Further, Solid-liquid phase PCM storage materials can be many choices of inorganic and organic PCM materials with desired transition temperature and effective heat capacity. Examples of such PCMs are set forth in Table 2 for low phase transition temperatures and Table 3 for high phase transition temperatures. Solid-liquid PCMs are usually packaged in secondary containers, in desired shapes and sizes, and positioned on layered shelves in the main container. Liquid-gas PCM heat exchange media can be many choices of liquids with desired liquid-gas phase transition and vapor pressure at the working temperature, and they may be the same materials as the HTFs or WFs, as set forth in Table 1.
(21) Two main methods can be used to effectively transfer the thermal energy into the container, between the HTF, the storage medium and the WF, and out of the container.
(22) According to exemplary implementations of a first method, a small amount liquid-gas PCM is positioned at the container bottom, in physical contact with input heat transfer device in pool boiling condition. Application of heat in the HTF via the input heat transfer device then quickly brings the liquid-gas PCM to evaporation state, transferring its latent heat energy into latent heat of a gas state of the liquid-gas PCM. In this case, the amount of liquid-gas PCM in the container is small so that it is easily to be heated up to desirable temperature, hence most of PCM is evaporated. The working temperature of the heat exchange container is determined by boiling point of liquid-gas PCM at a given pressure in the container. For example, using VP-1 synthetic oil as HTF, its boiling temperature at 0.1 MPa (or about one atmosphere pressure) is 257 C. If temperature increases to 320 C., its corresponding saturated vapor pressure is 0.36 MPa.
(23) As soon as liquid-gas PCM vapor in contact with the surfaces of secondary containers of solid-liquid PCM storage medium and/or the output heat transfer device (with, e.g., a WF flowing inside), vapor phase of PCM condenses into liquid phase, transferring its latent heat at an extremely high rate (supper-exchange) to the storage medium and/or WF that brings the thermal energy out of heat exchanger. Almost all of the condensation latent heat energy is instantly transferred from hot surfaces to the cold surfaces, making a very effective heat exchange system. In the process of transfer latent heat into the solid state thermal storage materials or WF, the condensation liquid droplets falls back to the bottom of the container by gravity force to re-start the heat transfer cycle, so that the entire system becomes an extremely efficient heat exchanger and thermal storage system. Note, the storage materials here are not in direct contact with the heat input and output piping surface, as with existing systems and methods.
(24) In a second exemplary method, the HTF and heat exchange media are the same liquid-gas PCM, in vapor form, which undergoes a slight reduction in pressure by passing through a throttling valve or other throttling device before entering the main container. When this vapor carrying the latent heat in physical contact with the surfaces of solid state and/or containers of solid-liquid phase change thermal storage materials, and WF via output heat transfer devices, the condensation process of the vapor transfers the latent heat of liquid-gas PCM vapor to thermal storage materials and/or WF.
(25) In an exemplary implementation, a 400 C. VP-1 pressurized vapor may be introduced into chamber, with the vapor transferring its latent heat either to the working fluid via the heat transfer output device or to a solid-liquid PCM material via a condensation process, at e.g. 380 C.; further, condensed VP-1 can enter into a second container at 380 C. and flash evaporate at a lower temperature, for example flash into 280 C., with 30% becoming vapor state.
(26) Turning back to the general system, in both cases, a circulating system may continuously supply a liquid PCM to the surface of secondary containers of the storage PCM, and transfer heat from the thermal storage material to the working fluid even if there is no input HTF flow.
(27) To control temperature in the container for a given container size, implementations herein may control the pressure by changing the ratio of vapor to liquid volumes using inert gas and liquid PCM reservoir control systems. For any given liquid-gas PCM, its vapor pressure and temperature have one to one relationship in a closed container. For example, if one fills a quantity of water equal to 5/1600 of the total void volume, the ultimate pressure in the heat exchange/thermal storage container will be five atmospheres, or 0.5 MPa. The corresponding ultimate temperature (liquid-gas phase change transition temperature at 5 atmospheres) will be 150 degree Celsius. A inert gas/liquid-gas PCM reservoir and circulating pump system are used to assure right ratio and pressure for constant heat exchange.
(28) The general principle of using gravity to circulate the evaporation and condensation process is commonly classified as two phase thermosiphons dates back to the steam age; this principle is widely used in one-dimensional thermosyphon device or heat pipe. The number of molecules (N in mole) that collide with unit surface area on condensing surface within unit time: N=Z.sub.m/N.sub.a=P/(square root[2RMT]), Where Z.sub.m is collision rate, N.sub.a is Avogadro's number, P is PCM pressure, T is PCM temperature in Kelvin, R is atmospheric constant, M is mole weight in kg. For example, at 100 C (373K) and 1 atmosphere (10.sup.5 pa) for water vapor molecules, N=5400 mole/sec m.sup.2=0.54 mole/sec cm.sup.2. If every water vapor molecule that collide with heat transfer surface condenses into liquid phase, latent heat released per second on each square centimeter is the Heat transfer rate=22 kJ/sec cm.sup.2=22 kW/cm.sup.2=220 MW/m.sup.2. At 180 C. (453K) and 10 atmosphere (1 MPa), N=48452 mole/sec m.sup.2=4.85 mole/sec cm.sup.2, heat transfer rate=180 kW/cm.sup.2=1800 MW/m.sup.2. In fact, there is only a fraction of molecules that hit heat transfer surface is condensed into liquid phase, the above estimated heat transfer rate is an upper limit for the practical value.
(29) The highest (World record) heat transfer rate for a heat pipe (which has the same working principle as a Thermosiphon) is 230 MW/m.sup.2, a value that is on the same order as the innovations herein. With the second example, every 8 water molecules that hit the surface is condensed into liquid phase while transfer the latent heat into condensed surfaces. It should be noted that this heat transfer rate value is 4 times the heat flux of the radiation from the Sun at its surface.
(30) Aspects of the present heat exchange innovations may have consistencies with a three-dimensional thermosiphon device, where evaporation-condensation latent heat exchange process simultaneously occurring between more than one surfaces of secondary containers or piping of different media within a 3-dimensional container. Effectively, inside heat exchange apparatus, the heat resistance is extremely small. Basically, heat conducting, rate between relatively lower and higher temperature surfaces of input and output heat transfer devices and storage materials is extremely high, reaching above the 100 MW/m.sup.2 level, as illustrated previously. Therefore, this heat transfer process is also called a thermal superconducting process. Further, consistent with aspects of the innovations herein, additional liquid circulating system may be added to assist heat transfer between storage PCM and WF, e.g., when there is no heat input by HTF from the heat input device.
(31) HTF temperature T.sub.1, heat exchange medium temperature T.sub.2, storage medium temperature T.sub.3 and WF temperature T.sub.4 have following relationship: T.sub.1>T.sub.2>T.sub.3>T.sub.4, T.sub.12=T.sub.1T.sub.2, T.sub.23=T.sub.2T.sub.3, T.sub.24=T.sub.2T.sub.4; T.sub.12 and T.sub.24 depend on flow rates of HTF and WF, physical structure of input and output heat transfer devices (mainly the heat transfer areas), thermal property of HTF and WF, and working pressure in the heat transfer container, which depends on the ratio of liquid to vapor volumes of liquid-gas PCM material in the heat exchange container. T.sub.23 depends on the states of storage PCM materials within their secondary containers.
(32) Phase change temperatures of the liquid-gas PCMs can be tuned by controlling the liquid-gas PCM vapor pressure in the heat exchange/thermal storage container. The main function of the PCM liquid is to keep the temperatures of all the solid state thermal storage material surfaces the same as WF heat transfer device surfaces via super heat conducting mechanism, i.e., evaporation-condensation process. Although the liquid-gas PCM also stores the energy, it is miner comparing with those of solid state thermal storage materials due to limited amount of liquid-gas PCM in the thermal storage container.
(33) A series of this type of heat exchange/storage containers with different vaporization or heat exchange temperatures can then be stacked together with HTF and WF connecting pipes in weak thermal link between them.
(34) Following is a relationship between the ratio of pressurized container material price versus PCM price: =Pg/Pp=(4/R+4/L).Math.d.Math.K (Eq. 3), where is the ratio, Pg is the container material (most of time, boiler steel) price, Pp is the PCM price, with Pg and Pp being price in weight; R is the radius of the cylindrical container, L is the length of the cylindrical container, d is the thickness of the cylindrical container wall, K is a special ratio that represent the unit price ratio of the container material versus PCM, it is in the range of 15 to 20 for many PCMs; This equation assumes that the thermal storage material's volume in the thermal storage container is about 50% of the total container volume. The wall thickness of the container should not exceed 3 cm in most cases. Therefore, we have the following simplified relationship: =Pg/Pp=0.15319+2.16/R, (Eq. 4).
(35) According to the heat transfer simulation based on the nature of PCM, such as the one we mentioned above, NaOH (73.2%)+NaCl (26.8%) mixture with latent heat of 370 kJ/kg, if this PCM mixture is packaged into a 5 cm diameter pipe (secondary container), within 5 hours, more than 80% PCM in the pipe will be melted when VP-1 vapor temperature is 10 degree higher than its melting point, 369 C. Therefore, an array of modular containers with secondary PCM cylindrical container size of 5 cm inside can be connected in parallel to form large enough capacity to supply sufficient thermal energy to meet power plant's need, since charging and discharging time scales are usually more than 5 hours.
(36) In a different application, thermal exchange/storage method described above can be used to eliminate the need for cooling water in the Rankine cycle and other processes, such as refrigeration and desalination. If the residual heat at the outlet of a heat engine, or appliances, such as Rankine cycle, heat pumps, desalination and refrigeration apparatus, can be stored during operation hour, then dissipated or used latter time, great amount of energy and water resources will be saved. For example, in a Rankine cycle involves a steam turbine generator, low temperature steam, e.g. at 60 C. is coming out from the outlet of the turbine. For 1 ton of steam, there are about 650 kWh of latent heat needed to dissipate by cooling water. Instead of dissipation by cooling water, we can use low temperature PCM listed in Table 3 to store the latent heat using the method and system described above and below in this disclosure. First, the exhaust steam vapor as HTF enters the storage/heat exchange container, it will contact with solid-liquid PCM with proper transition temperature, in this case 30-50 C., the vapor will condense into water at the surface of PCM secondary container; as the PCM is charged up, the shutoff valve of this container will be closed, and vapor will be feed into other parallel connected similar containers. To use the heat stored in this container, water/vapor will then be evacuated before a different liquid-gas PCM heat exchange medium with low boiling temperature will be introduced into the container through showering/dripping system onto the surface of storage secondary containers, and to be evaporated into vapor. The vapor then will deliver its latent heat to heat output device and working medium to heat appliances or to container surface to be dissipated into environment. If a modular storage container only stores the thermal energy from turbine outlet for a fraction of operating time, and then re-use or dissipate it for a much longer time frame at rest of the day, deployment of an array of this type of storage apparatus will eliminate the need for cooling water. Since PCM effective heat capacity can be 100 times larger than water, a much small volume of storage containers are needed in this application. To condense 1 ton of steam vapor in 1 hour, one only needs 9.3 ton of Na2SO4*10H2O PCM storage materials, if storage filling ratio is 0.5, the storage chamber only needs 12 m.sup.3 volume.
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(38) Using a circulation pump to pump in or out PCM liquid 118 from a small reservoir 130 and pressure control system 141 including inert pressurized gas (not shown in Figure) also controls the ratio of vapor 120 volume versus liquid 118 volume of PCM so that ultimate pressure, monitored by pressure gauge in 141 and data acquisition/control unit 144 and computer 145, thus the working temperature in thermal storage container is easily controlled. In addition, this working temperature is readily tuned continuously, to desired levels.
(39) The heat output device is part of a heat output system, which may also include the output tubing surfaces 222, the working medium/fluid itself 147, exit tubing 151 for the hot working medium/fluid, appliance 142, such as steam turbine, and return tubing 150 for the cooled working fluid circulating back into the chamber 114.
(40) As indicated above, the heat exchange system 130/132/134 delivers a heat exchange medium/fluid to the thermal storage material 126 surfaces. According to implementations herein, the heat exchange medium/fluid may be one or more media/fluids selected from the list of materials set forth in Table 1. The heat exchange system may also include one or more storage tanks 130 as well as various pumps, valves and other flow control elements 132.
(41) As set forth in more detail in association with
(42) The system of
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(44) The thermal storage medium 226 is located within the chamber 214 and has defined thermal storage surfaces. In the exemplary implementation of
(45) The heat output device is part of a heat output system, which may also include the output tubing surfaces 222, the working medium/fluid itself 247, exit tubing 251 for the hot working medium/fluid, a storage tank 242, and return tubing 250 for the cooled working fluid circulating back into the chamber 214.
(46) As indicated above, the heat exchange system 230/232/234 delivers a heat exchange medium/fluid to the thermal storage material 226 surfaces. According to implementations herein, the heat exchange medium/fluid may be one or more media/fluids selected from the list of materials set forth in Table 1. The heat exchange system may also include one or more storage tanks 230 as well as various pumps, valves and other flow control elements 232.
(47) As set forth in more detail in association with
(48) The system of
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(50) Using a circulation pump to pump PCM liquid 318 in or out from a small reservoir 330 and pressure control system 341/344 may be used to control the ratio of vapor 320 volume versus liquid 318 volume of PCM so that both ultimate pressure, monitored by pressure gauge in 341 and data acquisition/control unit 344 and computer 345, and working temperature in the thermal storage container may be easily controlled in time sequence. In addition, the system may be configured such that this working temperature may be tuned continuously to a desired temperature or range. Again, as the storage materials 326 is charged full, the input entry for the exhaust vapor may be closed, and the circulating pump 332, small reservoir of 330 and showerhead device 334 may be used to release the stored thermal energy in the thermal storage materials within the secondary storage materials containers so that the stored thermal energy can be dissipated through the container 314 surfaces via thermal communication with the environment. During this time, the exhaust vapor can be channeled to one or more different storage systems 343. In this configuration, the system serves as an exhaust vapor condensation system, eliminating the need for water/air circulation cooling system.
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(52) The thermal storage medium 426 is located within the chamber 414 and has defined thermal storage surfaces, such as is explained in more detail in connection with
(53) The heat output device is part of a heat output system, which may also include the output surfaces 422, the working medium/fluid itself 447, exit tubing 451 for the hot working medium/fluid, a heat appliance (such as turbine) 442, and return tubing 450 for the cooled working fluid circulating back into the chamber 414.
(54) As indicated above, the heat exchange system 456/455/434 delivers a heat exchange medium/fluid to the thermal storage material 426 surfaces. According to implementations herein, the heat exchange medium/fluid may be one or more media/fluids selected from the list of materials set forth in Table 1. The heat exchange system may also include one or more storage tanks 456, 430 as well as various valves 455 and other flow control elements 432. In some implementations, e.g., to use the heat stored in the chamber 414, the HTF vapor may be evacuated prior to a different liquid-gas PCM heat exchange medium associated with a second storage tank 430 being introduced into the container through the showerhead 434 onto the surface of storage secondary containers 426, and to be evaporated into vapor. This vapor then will deliver its latent heat to heat output device and working medium.
(55) As set forth in more detail in association with
(56) The system 400 may also include a variety of other valves and interconnections as set forth throughout this disclosure, including a valve 440 that serves to couple the heat transfer fluid system to adjacent/associated heat transfer systems, such as to a heat storage tank 443 in another such system.
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(58) The thermal storage medium 526 is located within the chamber 514 and has defined thermal storage surfaces. In the exemplary implementation of
(59) The heat output device is part of a heat output system, which may also include the output surfaces 522, the working medium/fluid itself 547, exit tubing 551 for the hot working medium/fluid, a heat appliance (such as a turbine) 542, and return tubing 550 for the cooled working fluid circulating back into the chamber 514.
(60) As indicated above, the heat exchange system 556/555/534 delivers a heat exchange medium/fluid to the thermal storage material 526 surfaces. According to implementations herein, the heat exchange medium/fluid may be one or more media/fluids selected from the list of materials set forth in Table 1. The heat exchange system may also include one or more storage tanks 556, 530 as well as various valves 555 and other flow control elements 532. In some implementations, e.g., to use the heat stored in the chamber 514, the HTF vapor may be evacuated prior to a different liquid-gas PCM heat exchange medium associated with a second storage tank 530 being introduced into the container through the showerhead 534 onto the surface of storage secondary containers 526, and to be evaporated into vapor. This vapor then will deliver its latent heat to heat output device and working medium and/or to chamber 514 surfaces to be dissipated to the environment.
(61) As set forth in more detail in association with
(62) The system of
(63)
(64) Referring to
(65) The volume of liquid state of PCM 618 is much smaller than the vapor form 620 which fills empty space volume in container 614, including void volume of solid materials 626 with a certain ratio. In operation, the vapor form 620 fills the entire container 614 upon contact with the lower-temperature surfaces of solid thermal storage material 626 and the non-insulated container 614 surfaces, the vapor 620 condenses instantly into liquid while transferring latent heat to storage materials 626, or dissipated into environment via thermal communication between the surfaces of chamber 614 and the environment. Condensed PCM liquid droplets 619 then drip down to the bottom of storage container 614 to be transferred out of chamber via tubing 652 back to the heat appliance until all thermal storage materials 626 surface reach thermal equilibrium with input vapor 620. The heat exchange medium condensation temperature controlled by pressure control system 641/644/645.
(66) The system may be configured such that the working temperature may be tuned continuously to a desired temperature or range. Again, as the thermal storage materials 626 is charged in full, the input entry for the exhaust vapor may be closed, and the circulating pump 632, small reservoir of 656 and showerhead device 634 may be used to release the stored thermal energy in the thermal storage materials within the secondary storage material containers so that the stored thermal energy can be dissipated through the container 614 surfaces via thermal communication with the environment. During this time, the exhaust vapor can be channeled to one or more different storage system 644. In this configuration, the system serves as an exhaust vapor condensation system, eliminating the need for water/air circulation cooling system.
(67) The implementations herein may also easily cascade into several subsystems connected together in series, as illustrated in
(68) Accordingly, as a result of the innovations herein, one or more of the following features may be achieved: 1) innovations that greatly improve heat exchanger design configurations; 2) easy transfer of thermal energy to and from thermal storage containers/solid thermal storage materials, enabling innovative and efficient utilization of solid thermal storage materials, achieving reduced cost of thermal storage; 3) greatly improvements in heat exchange efficiencies of thermal storage containers; 4) improved features of utilizing the solid to liquid phase change latent heat via packaging of PCMs; and/or 5) vapor input process methods that carries latent heat thermal energy, which also enables control of the working pressure and temperature in the thermal storage container.
(69)
(70) This property is especially important for concentration solar thermal applications. For any given concentration solar thermal collecting field, there is an upper limit for the highest temperature this solar field can achieve. For example, for a synthetic oil based trough system, due to upper temperature limit of the synthetic oil, the highest temperature this solar field can reach is 400 C. For a thermal storage system with highest stored temperature at 400 C., the higher the temperature and pressure steam it generated, the higher thermal to electricity conversion efficiency it can achieve, the cost of the electricity can be lowered. For example, with current thermal storage design, a solid-liquid PCM, such as a crystal mixture of Sodium Chloride and Sodium Hydroxide salts with phase change temperature at 385 C. and thermal storage density at 370 kJ/kg, can be used to store the thermal energy at 385 C. during the day and release the thermal energy during the evening. This stored thermal energy is able to generate water steam at 360 C. with pressure of 18.5 MPa pressure. If one wants to use two container molten salt thermal storage system to achieve the same effect, the amount of thermal storage material used has to be 15 to 20 time more than the solid-liquid PCM thermal storage material. The closer the generated steam's temperature to the upper temperature limit (400 C., in this case), the more advantage of PCM against the sensible-heat thermal storage solution.
(71)
(72)
(73)
(74)
(75) With regard to computing components and software embodying the inventions herein, such as the heat transfer and/or storage methods, the innovations herein may be implemented/operated consistent with numerous general purpose or special purpose computing system environments or configurations. Various exemplary computing systems, environments, and/or configurations that may be suitable for use with the innovations herein may include, but are not limited to, personal computers, servers or server computing devices such as routing/connectivity components, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, smart phones, consumer electronic devices, network PCs, other existing computer platforms, distributed computing environments that include one or more of the above systems or devices, etc.
(76) The invention may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer, computing component, etc. In general, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
(77) Computing component/environment 180 may also include one or more type of computer readable media. Computer readable media can be any available media that is resident on, associable with, or can be accessed by computing component/environment 180. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and can accessed by computing components. Communication media may comprise computer readable instructions, data structures, program modules or other data embodying the functionality herein. Further, communication media may include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of the any of the above are also included within the scope of computer readable media.
(78) In the present description, the terms component, module, device, etc. may refer to any type of logical or functional process or blocks that may be implemented in a variety of ways. For example, the functions of various blocks can be combined with one another into any other number of modules. Each module can be implemented as a software program stored on a tangible memory (e.g., random access memory, read only memory, CD-ROM memory, hard disk drive) to be read by a central processing unit to implement the functions of the innovations herein. Or, the modules can comprise programming instructions transmitted to a general purpose computer or to processing/graphics hardware via a transmission carrier wave. Also, the modules can be implemented as hardware logic circuitry implementing the functions encompassed by the innovations herein. Finally, the modules can be implemented using special purpose instructions (SIMD instructions), field programmable logic arrays or any mix thereof which provides the desired level performance and cost.
(79) As disclosed herein, implementations and features of the invention may be implemented through computer-hardware, software and/or firmware. For example, the systems and methods disclosed herein may be embodied in various forms including, for example, a data processor, such as a computer that also includes a database, digital electronic circuitry, firmware, software, or in combinations of them. Further, while some of the disclosed implementations describe components such as software, systems and methods consistent with the innovations herein may be implemented with any combination of hardware, software and/or firmware. Moreover, the above-noted features and other aspects and principles of the innovations herein may be implemented in various environments. Such environments and related applications may be specially constructed for performing the various processes and operations according to the invention or they may include a general-purpose computer or computing platform selectively activated or reconfigured by code to provide the necessary functionality. The processes disclosed herein are not inherently related to any particular computer, network, architecture, environment, or other apparatus, and may be implemented by a suitable combination of hardware, software, and/or firmware. For example, various general-purpose machines may be used with programs written in accordance with teachings of the invention, or it may be more convenient to construct a specialized apparatus or system to perform the required methods and techniques.
(80) Aspects of the method and system described herein, such as the logic, may be implemented as functionality programmed into any of a variety of circuitry, including programmable logic devices (PLDs), such as field programmable gate arrays (FPGAs), programmable array logic (PAL) devices, electrically programmable logic and memory devices and standard cell-based devices, as well as application specific integrated circuits. Some other possibilities for implementing aspects include: memory devices, microcontrollers with memory (such as EEPROM), embedded microprocessors, firmware, software, etc. Furthermore, aspects may be embodied in microprocessors having software-based circuit emulation, discrete logic (sequential and combinatorial), custom devices, fuzzy (neural) logic, quantum devices, and hybrids of any of the above device types. The underlying device technologies may be provided in a variety of component types, e.g., metal-oxide semiconductor field-effect transistor (MOSFET) technologies like complementary metal-oxide semiconductor (CMOS), bipolar technologies like emitter-coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, and so on.
(81) It should also be noted that the various logic and/or functions disclosed herein may be enabled using any number of combinations of hardware, firmware, and/or as data and/or instructions embodied in various machine-readable or computer-readable media, in terms of their behavioral, register transfer, logic component, and/or other characteristics. Computer-readable media in which such formatted data and/or instructions may be embodied include, but are not limited to, non-volatile storage media in various forms (e.g., optical, magnetic or semiconductor storage media) and carrier waves that may be used to transfer such formatted data and/or instructions through wireless, optical, or wired signaling media or any combination thereof. Examples of transfers of such formatted data and/or instructions by carrier waves include, but are not limited to, transfers (uploads, downloads, e-mail, etc.) over the Internet and/or other computer networks via one or more data transfer protocols (e.g., HTTP, FTP, SMTP, and so on).
(82)
(83) Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in a sense of including, but not limited to. Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words herein, hereunder, above, below, and words of similar import refer to this application as a whole and not to any particular portions of this application. When the word or is used in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list.
(84) Although certain exemplary implementations of the present innovations have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various implementations shown and described herein may be made without departing from the spirit and scope of innovations consistent with this disclosure. Accordingly, it is intended that the innovations be limited only to the extent required by the appended claims and the applicable rules of law.
(85) TABLE-US-00001 TABLE 1 Heat transfer, working fluid, and heat exchange media BOILING HEAT VAPOR MOLE POINT NORMAL BP ITEM COMPONENT WT K (TB) CAL/G-MOLE THE LOW-BOILING CHLOROFORM 119.378 334.3 7100 SUBSTANCES METHANOL 32.042 337.8 8426 ACETYL CHLORIDE 78.498 323.9 6850 CYCLOPENTANE 70.080 322.3 6536 PROPIONALDEHYDE 58.080 321.0 6760 N-PROPYLAMINE 59.112 321.8 7100 2,3-DIMETHYL-1-BUTENE 84.162 328.8 6550 THE MID-BOILING O-ETHYLPHENOL 122.167 477.7 11490 SUBSTANCES ETHYL BENZOATE 150.178 485.9 10700 1,2,3,4-TETRAHYDRONAPHTHALENE 132.206 480.7 9490 N-HEXYLCYCLOPENTANE 154.297 476.3 9840 1-DODECENE 168.324 486.5 10270 VP-1 HEAT TRANSFER OIL 166.000 530.0 11171 THE HIGH-BOILING N-OCTADECANE 254.502 589.5 13020 SUBSTANCES N-PENTADECYLCYCLOPENTANE 280.540 625.0 13780 1-EICOSANOL 298.555 629.0 15600
(86) TABLE-US-00002 TABLE 2 Low Temperature PCMs Thermal conductivity Compound T.sub.m, C. H.sub.f, KJ/Kg Density, (Kg/m.sup.3) (W/(mK)) abio-hydrous LiNO3*3H2O 30 296 salt Na2SO4*10H2O 32.4 254 1485 0.544 Na2CO3*10H2O 33 247 1349 (liguid, 84 C.) 1447 (solid, 24 C.) Na2HPO4*10H2O 36 281 1522 Na2S2O3*5H2O 48 209.3 1600 Na(CH3COO)*3H2O 58 226 1450 Na2P2O4*10H2O 70 184 50%Na(CH3COO)*3H2O + 40.5 255 50%HCO NH2 Ba(OH)2i*8H2O 78 280 1937 (liquid, 84 C.) 0.678 (98.2 C.) 2070 (solid, 24 C.) 1.225 (23 C.) paraffin C16~C28 42~44 189 765 (liquid, 70 C.) 0.21 910 (solid, 20 C.) C20~C33 48~50 189 769 (liquid, 70 C.) 0.21 912 (solid, 20 C.) C20~C45 58~60 189 795 (liquid, 70 C.) 0.21 920 (solid, 20 C.) C21~C50 66~68 189 830 (liquid, 70 C.) 930 (solid, 20 C.) sliceable paraffin 64 173.6/266 790 (liquid, 65 C.) 0.167 (63.5 C.) 916 (solid, 24 C.) 0.346 (33.6 C.) fatty acid lauric acid 42~44 177.4/178 862 (liquid, 60 C.) 0.147 1007 (solid, 24 C.) tetradecanoic acid 49~51 187 861 (liquid, 55 C.) 990 (solid, 24 C.) cetylic acid 63 187 850 (liquid, 65 C.) 0.162 989 (solid, 24 C.) stearic acid 70 203 848 (liquid, 70 C.) 965 (solid, 24 C.) products in ClimSel C32 (hydrous salt) 32 212 1450 used RT40 (paraffin state) 43 181 STL47 (hydrous salt) 47 221 1340 ClimSel C48 (hydrous salt) 48 227 1360 STL52 (hydrous salt) 52 201 1300 RT50 (paraffin state) 54 195 1290 STL55 (hydrous salt) 55 242 TH58 (hydrous salt) 58 226 ClimSel C48 (hydrous salt) 58 259 1460 RT65 (paraffin state) 64 207
(87) TABLE-US-00003 TABLE 3 High Temperature PCMs melting substance 1 (mol %) substance 2 (mol %) substance 3 (mol %) point C. H.sub.i, kwh/t MnCl2 37.3 NaCl 25 KCl 37.7 400 65.3 LiCO3 32 K2CO3 35 NaCO3 33 397 76.7 MgCl2 50 KCl 20 NaCl 30 396 80.8 MgCl2 51 KCl 22 NaCl 27 396 80.6 KCl 45.5 MnCl2 34.5 NaCl 20 390 63.9 MgCl2 63.7 NaCl 22.3 KCl 14 385 128.1 KOH 380 41.6 NaOH 73.2 NaCl 26.8 369 102.5 KCl 28.7 MnCl2 45 NaCl 26.3 350 59.7 KCl 0.61 FeCl2 0.39 345 KNO3 335 24.44 NaOH 77.2 NaCl 16.2 Na2CO3 6.6 318 80.6 NaOH 318 44.17 KNO3 0.905 KCl 0.095 308 47.2 NaNO3 0.98 Na2CO3 0.02 307 NaNO3 307 49.17 NaNO3 0.965 NaF 0.035 303 NaCl 0.066 NaNO3 0.934 298 58.9 NaOH 85.8 NaCl 7.8 Na2CO3 6.4 298 79.4 NaCl 0.066 NaNO3 0.934 298 NaNO3 0.95 Na2SO4 0.05 296 NaNO3 0.95 Na2SO4 0.05 296 NaOH 0.94 Na2SO4 0.06 294 NaOH 87.3 NaCl 6.1 Na2CO3 6.6 291 78.6 NaCl 8 NaF 5 NaNO3 87 288 62.2 NaNO3 86.3 NaCl 8.4 Na2SO4 5.3 287 49.17 Na2CO3 0.08 NaOH 0.92 286 94.4 NaOH 88.3 NaCl 5.3 Na2CO3 6.4 282 77.5 NaNO3 0.41 NaOH 0.59 266 77.2 KCl 0.28 ZnCl2 0.72 264 NaNO3 0.194 NaOH 0.806 258 69.7~81.1 NaNO3 0.615 NaOH 0.285 250 43.89 NaNO3 0.615 NaOH 0.285 250 158 NaOH 55.6 NaCl 4.2 NaNO3 40.2 247 59.2 NaNO3 18.3 NaCl 3.6 NaOH 78.1 242 67.2 NaOH 30 NaNO3 70 247 43.9 NaOH 28 NaNO3 72 246~247 50.6~71.4