English:
[0001] Over the years, efforts have been undertaken to obtain work or power through an engine that is driven by different principles of thermodynamics. For example, techniques for generating electrical power from equipment relying on the "Stirling" or "Organic Rankine" cycle (ORC) have been developed. Unfortunately, these technologies have been generally ineffective and inefficient without the requirement of highly elevated temperatures. For example, lower heat sources, say below the boiling point of water, have been largely ineffective.
[0002] By way of example, ORC engine manufacturers often provide a system that allows for operation with input heat temperatures as low as 170°F. So, for example, a refrigerant that might more easily move from a liquid to a gas state may be utilized wherein turbine or turbine-like technology converts the pneumatic forces of the gas to generate productive work. However, a dramatically reduced output is generally also attained, thereby making the undertaking significantly less economical. In part, this is due to the properties of the working fluids used by ORC and the range and efficiency capabilities of the machinery extracting work from the working fluid.
[0004] The ORC engines noted above convert a liquid with a low boiling temperature to its gas state and channels the gas or gas-and-liquid mixture through a turbine-like device to produce rotary motion. Apart from the inefficiencies noted above, such engines operate at a rotational speed of near 5,000 rpm or more. The gas mixture is then cooled back to a liquid state, changing phase again before reuse. Even setting aside inefficiencies, such speed and dramatic phase changes create significant noise, not unlike a jet engine.
[0005] Another technology that has been attempted is known as "thermal hydraulic heat engines". This technology involves the use of heat applied to a liquid that may have a relatively high coefficient of expansion. As a practical matter, however, most liquids expand very little when heated and contract very little when cooled. Thus, in actual practice, such engines fail to attain successful commercialization due primarily to the difficulty of obtaining sufficient expansion, and sufficiently rapid expansion and contraction, in liquids. This limits the economic viability of such engines. Further, even when utilized, such engines are only practical for use in a narrow set of specific circumstances. This is because of the general inflexibility in terms of available modifications for differing uses. In fact, extensive trial and error is generally required even for the circumstances in which the engines may be effectively utilized. This is due, in part, to the inherent limitation involved with placing primary reliance on the expansion and contraction of a liquid by the introduction and removal of heat.
[0007] Fig. 1 is a top view depiction of an embodiment of a high dynamic density range thermal cycle engine to provide work.
[0008] Fig. 2 A is a side view depiction of the thermal cycle engine of Fig. 1.
[0009] Fig. 2B is an opposite side view depiction of the thermal cycle engine of Figs. 1 and 2.
[0010] Fig. 3 is a schematic representation of an engine layout for the thermal cycle engine of Fig. 1.
[0011] Fig. 4A is a schematic illustration of an embodiment of an opposing piston assembly of the engine of Fig. 1.
[0012] Fig. 4B is a chart depicting an embodiment of a thermal cycle providing a work output based on an expansion and compression profile for the piston assembly of Fig. 4A.
[0013] Fig. 5A is a perspective view of a portion of an embodiment of a tubesheet heat exchanger of the engine of Fig. 1.
[0014] Fig. 5B is a front view of a hexagonal configuration of the tubesheet heat exchanger of Fig. 5 A.
[0015] Figs. 6A-6E are schematic illustrations of the opposing piston assembly of Fig. 4A with movement sequence over time during operation.
[0016] Fig. 7 is a flow-chart summarizing an embodiment of employing a thermal cycle engine utilizing closed loop dedicated heat exchangers.
[0017] In the following description, numerous details are set forth to provide an understanding of the present disclosure. However, it will be understood by those skilled in the art that the embodiments described may be practiced without these particular details. Further, numerous variations or modifications may be employed which remain contemplated by the embodiments as specifically described.
[0018] Embodiments detailed herein are directed at a unique manner of controlling the expansion and contraction of a working substance in the form of a supercritical fluid within a closed loop or container. Specifically, this expansion and contraction of the working substance is used to move a piston in order to ultimately generate productive work. When generating power with a motor attached to a generator, the engine may display a "low" rotational speed of less than about 50 rpm. Further, embodiments detailed herein may avoid changes in phase, and so are inherently more thermodynamically efficient, and with the appropriate operating fluid may operate effectively using input temperatures below 200°F. In fact, they can easily be tuned to operate with minor reductions in efficiency with input heat below 150°F. It also operates almost silently. However, in other embodiments, alternative temperature ranges and different rotational speeds may be utilized along with an allowance for some degree of phase change for the fluid. So long as both heating and cooling of a chamber containing the fluid is governed by the same heat exchanger, appreciable benefit may be realized.
[0019] Referring now to Fig. 1 with added reference to Fig. 3, a top view of an embodiment of a thermal cycle engine 100 is depicted. The engine 100 is provided on a skid frame 150 where a host of engine components are securely held in modular fashion. As alluded to above, dedicated heat exchangers 110, 120 are provided that are in hydraulic communication with only one side of a piston assembly 105 (also see the piston 205 of Fig. 2). That is, as illustrated in the schematic of Fig. 3, a closed reservoir of fluid may be circulated between a heat exchanger 110 and a chamber at one side of a piston assembly 105 over a dedicated line 309. Similarly, another closed reservoir of fluid may be circulated between the other heat exchanger 120 and a chamber at the opposite side of the piston assembly 105 over another dedicated line 308.
[0020] Other engine components are apparent with reference to the top view of Fig. 1. For example, note a hydraulic accumulator 180 which may work in synchronization with valving at a manifold 125 to periodically provide added force to piston strokes. A hydraulic reservoir 175 is also apparent. With added reference to Fig. 3, this reservoir 175 may serve as (or supply) a hot 390 or cold 375 fluid tank. Specifically, a pump 160 may be used to circulate hot water from a tank 390 and associated heat source 350 to heat the appropriate heat exchanger (110 or 120) at the appropriate time depending on the position of the stroking piston within the piston assembly 105. As noted, in one embodiment, this water may be between about 150°F and about 200°F.
[0021] By the same token another pump (not visible in Fig. 1) may be used to circulate cold water from the cold fluid tank 375 and cooling source 325 to the appropriate heat exchanger (110 or 120) at the appropriate time. In one embodiment, the cold water is water that is kept at about room temperature, perhaps from an adjacent body of water. That is, there is not necessarily a requirement that undue energy be spent actively cooling the water. However, in other embodiments, an evaporative cooler may be utilized.
[0022] With specific reference to Fig. 3, with brief added reference to Fig. 4A, it is worth noting that the timing for heating the first heat exchanger 105 will coincide with the timing for cooling the second heat exchanger 120 and vice versa. Thus, as pressure within the piston assembly 105 is increased at a first chamber 455 it is simultaneously decreased within an opposite second chamber 457, thereby enhancing the stroking of the piston 400 (e.g. in a downward direction as depicted in Fig. 4A). Of course, at the end of the stroke, the process is reversed with the second heat exchanger 120 being heated, the first 110 being cooled, the chambers 455, 457 reversed in differential pressure with the second 457 being higher and the piston 400 stroked in the opposite direction (e.g. upward as illustrated in Fig. 4A).
[0023] Returning to Fig. 3, recall that each heat exchanger 110, 120 is equipped with its own dedicated line 307, 308 running to the piston assembly 105. Specifically, with added reference to Fig. 4A, the dedicated line 307 running from the first heat exchanger 110 is in fluid communication with the first chamber 455 of the assembly 105. Alternatively, the dedicated line 308 from the second heat exchanger 120 is in fluid communication with the second chamber 457. In this manner two separate closed loop hydraulic systems are provided with the piston 400 of Fig. 4A cyclically stroking in the direction of reduced volume and pressure and away from increased volume and pressure on a continual basis. However, these hydraulic loops, between chamber and heat exchanger (e.g. 455/110 and 457/120), remain closed. That is, the fluid circulating to the heat exchangers 110, 120 from hot 375 or cold 390 water tanks is not mixed with the noted closed loop hydraulic systems. Instead, as heated water enters a given exchanger, an appropriately selected operating fluid rapidly expands outward therefrom and as cooled water enters, the operating fluid rapidly contracts back into the exchanger. Also note that this temperature regulating fluid may be water or other fluid of a different type than that within the closed loop systems. By way of contrast, the closed loop systems may utilize supercritical carbon dioxide (C02) as the operating fluid due to unique expansive properties as detailed below.
[0024] The described thermodynamic cycling may be uniquely efficient, effectively utilizing input temperatures below 200°F. Indeed, the cycling may be tuned to operate at below 150°F without substantial reduction in efficiency. As a result, the engine 100 may flexibly take advantage of a host of available heat sources. For example, useful work may ultimately be obtained from low grade heat sources such as geothermal heat, solar heat or the waste heat from other unrelated system operations. This allows for an effective and economical utilization of a vast array of heat sources previously considered to be too cool and of no practical economic value.
[0025] As detailed further below, where the operating fluid in the closed loops is CO2, keeping it in a supercritical or superheated gas state may be less of a challenge. As a result, the application of heating increases the volume and achieves dramatic expansion in order to increase pressure and drive the piston movement as discussed above. Further, the application of cooling the operating fluid prompts it to take on a smaller volume, thus further encouraging piston movement where applied to an opposite chamber from that of the heating. As detailed further below, this thermal cycle is particularly efficient where the operating fluid is able to avoid phase change for the substantial duration of the cycle.
[0026] Referring now to Fig. 2 A, a side view depiction of the thermal cycle engine 100 of Fig. 1 is shown. In this view some additional engine components are visible. For example, the frame accommodates the initially depicted piston assembly 105 as well as another piston assembly 205 to effectively double the output as discussed further below. So, for example, a heat exchanger 110 may govern a closed loop that includes the chamber 455 of one assembly 105 as well as another chamber of another assembly 205 (again see Fig. 4A). Along these lines, a host of additional piston assemblies may be added to the engine if so desired. Regardless, in the embodiment shown, the piston assemblies 105, 205 may cycle in synchronicity, perhaps with the added aid of valving also discussed further below.
[0027] In addition to the hydraulic reservoir 175, accumulator 180 and manifold 125 as described above, a hydraulic motor 200 is also apparent in Fig. 2A. Specifically, work from the thermal cycle engine 100 is ultimately transferred through to a motor 200 where it may ultimately be employed to generate and transmit power.
[0028] Continuing with reference to Fig. 2A, various hydraulic lines are also shown for circulating hot and cold water to and from the heat exchangers 110 (and 120 of Fig. 1). More specifically, cold water supply 280 and return 220 lines are provided as well as hot water supply 260 and return 240 lines. Thus, the appropriate temperature effectuating water type may be circulated to and from the appropriate heat exchanger 110, 120 at the appropriate time as discussed above (see Fig. 1).
[0029] Referring now to Fig. 2B, the engine 100 is shown from the opposite side as compared to Fig. 2A. In this view, the same water circulation lines 220, 240, 260, 280 are apparent as well as the other heat exchanger 120. The piston assemblies 105, 205 are also apparent along with the accumulator 180. Additionally, the hot pump 160 described above that is used to circulate hot water to the appropriate heat exchanger (110 or 120) at the appropriate time is shown as well as a cold pump 260 that is used to circulate cold water to the appropriate heat exchanger (110 or 120) at the appropriate time.
[0030] Referring now to Fig. 3, a schematic representation of an engine layout for the thermal cycle engine 100 of Figs. 1, 2A and 2B is shown. As indicated above, this engine 100 ultimately facilitates work output from a motor 200 in a uniquely efficient manner. This includes utilizing a unique system of heat exchangers 110, 120 where each exchanger 110, 120 is independently dedicated to one side of the pump assembly 105. This means that each exchanger 110, 120 defines and governs a closed hydraulic loop in which both the high and low temperature cycles are managed through the same exchanger 110, 120 for the given side of the assembly 105. Thus, a heated input is applied alternatingly to each exchanger 110, 120 in sequence (e.g. from heat source 350 and hot water tank 390). At the same time, a cold input is applied alternatingly to the opposite exchanger 110, 120, and also in sequence (e.g. from the cold source 325 and cold water tank 375).
[0031] Continuing with reference to Fig. 3, the reciprocating piston 400 within the assembly 105 circulates hydraulic oil through the manifold 125 which houses a variety of check valves timed to ensure proper reciprocation and timing of the piston 400 (see Fig. 4A). Indeed, the manifold 125 is also in hydraulic communication with the indicated accumulator 180 which may periodically charge and supply a flow of working fluid to a when the piston 400 is not moving or supply added pressure back through the manifold 125 to facilitate piston reciprocation (e.g. at the end of piston strokes). Further, even the motor 200 itself may play a role in the timing of piston reciprocation. For example, the motor 200 may be configured to operate at a substantially constant fixed speed, perhaps below about 50 rpm. Apart from being efficient and near silent, this type of constant fixed displacement may be hydraulically linked back through the manifold 125 to further help regulate the rate of piston reciprocation. Ultimately, a very controlled and reliably synchronized manner of reciprocation and output may be attained.
[0032] Referring now to Fig. 4A, a schematic illustration of an embodiment of an opposing piston assembly 105 of the engine 100 of Fig. 1 is shown. The illustration reveals the piston 400 within the assembly 105 that is reciprocated between chambers 455, 457 which are themselves a part of separate closed loop systems circulating operating fluid. In the embodiment shown, the operating fluid is C02, generally in a supercritical state as discussed further below. Additionally, as the piston 400 is reciprocated, intermediate chambers 487, defined by an intermediate head 440 are used to circulate an incompressible working fluid such as hydraulic oil toward a series of valves 475 and ultimately a motor 200 as discussed above. The motor 200 may be a hydraulic motor or even a crankshaft and the valves 475 may be modularly incorporated into the manifold 125 as described above (see Fig. 3). In this way, the circulating hydraulic oil may provide work that is translatable through a motor 200. The motor may then be utilized for the production of electrical power through a generator. However, a pump, motive power or compressor may also be driven by the motor or the hydraulic power may even be used directly without any connection to a motor.
[0033] In the embodiment shown, the intermediate chambers 487 are bordered by compartments 480, 485. These may be air filled compartments 480, 485 which serve as a sealing buffer between the working fluid chambers 455, 457 and the hydraulic oil of the intermediate chambers 487. The timing of valve 475 opening and closing as well as the rpm of the motor 200 also help synchronize this circulation and the piston reciprocation. For example, valves 475 may momentarily close each time the piston nears the end of each stroke so as to drive up pressure and help initiate stroking in the opposite direction. Such timing may be regulated by an electronic controller.
[0034] Referring now to Fig. 4B, a chart depicting an embodiment of a thermal cycle providing a work output based on an expansion and compression profile for the piston assembly of Fig. 4A is shown. This type of chart may be referred to as a P-v diagram. Specifically, the chart reveals a chamber (e.g. 455) being pressurized by way of heating. This can be seen in the move from (1) to (2) with the pressure moving up from about 1,200 psi to perhaps over 1,500 psi as the temperature rises from about 100°F to a little over 150°F. Thus, the pressure in the chamber 455 acts upon the piston head 450 and effects a volume increase with the piston 400 moving in a downward direction. Note the move from (2) to (3) in Fig. 4B reflecting the volume increase. Notice that the temperature also begins to slightly drop at this point. However, a much more dramatic drop, from (3) to (4) is effectuated by the tailored introduction of cold through the heat exchange technique described above. Specifically, at (4) the temperature has moved from a little under 150°F at (3) to below about 100°F. Note that this is still above 88°F (which ensures that the C02remains supercritical). Thus, at this point movement of the piston toward this chamber 455 would be encouraged, particularly in light of the other chamber 457 being heated according to the techniques described above. Indeed, notice the corresponding volume reduction in this chamber 455 with the move from (4) back over to (1).
[0035] In the embodiment of Fig. 4B, with added reference to Fig. 4 A, the pressure and temperature combination within the chamber 455 are maintained at levels where the operating fluid, in this case C02is kept in a supercritical state. This is not necessarily required for effective operation. However, greater efficiencies will be attained where the operating fluid is kept in a supercritical or superheated gas state throughout the substantial duration of the thermal cycle. More specifically, avoiding undue phase change of the operating fluid into and out of a liquid or "dense" state may enhance efficiency. Further, with the techniques and equipment setup detailed here, operating substantially outside of the "phase change dome" throughout is readily attainable.
[0036] It is worth noting that for alternative operating fluids, a host of different pressures and temperature ranges may be employed to maintain the fluid in a supercritical or superheated gas state for the substantial duration of the cycle. In the embodiment shown, CO2 is utilized given that it allows for relatively low heat and manageable pressures to rapidly and readily display these characteristics. However, other fluid types may be modeled and discretized. Additionally, a variety of piston dimensions and other variables evaluated for alternative tolerances that may be utilized in running a thermal cycle according to the techniques described here.
[0037] Referring now to Fig. 5A, a perspective view of an embodiment of a tubesheet heat exchanger 110 of the engine 100 of Fig. 1 is shown. The exchanger 110 is of a robust configuration that is tailored to handle the rapid heating and rapid cooling stressors that are placed on it during thermal cycles as described above and further below. Thus, the portion of the exchanger 110 depicted may be housed in a thick or double walled shell capable of withstanding the stress of continual and rapid heating and cooling. In this regard, stainless steel or other robust material choices may be employed.
[0038] Since the heat exchanger is determinative of the amount of energy addition and rejection over the course of thermal cycling, the sizing of the entire engine 100 of Fig. 1 begins with the sizing of the exchangers 110, 120. In the embodiment of Fig. 5A, a tubesheet exchanger 110 includes a plurality of micro-tubes 500 held in position by alignment plates 525, 575. In contrast to a conventional exchanger, the depicted tubesheet exchanger 110 does not have the operating fluid pass through. Instead, the exchanger acts as a reservoir which holds the operating fluid. Thus, upon application of heat as described above, the fluid rapidly expands, largely leaving the exchanger 110, or upon application of cooling, the fluid rapidly contracts back into the smaller volume of exchanger 110 (e.g. as described above). Not only does the fluid type affect the rate of this process but so too does the tubular nature of the exchanger 110 which effectively dramatically increases the surface area of the exchanger 110 acting upon the operating fluid.
[0039] With particular reference to Fig. 5B, a front view of a hexagonal configuration of the tubesheet heat exchanger of Fig. 5 A is shown in hexagonal form. The spacing of the tubes 500 may be defined by a predetermined pitch (P) and diameter (D) that are set based on a variety of other variables such as thickness of the tube walls. So, for example, this particular value may be of significance given the durable nature of the exchanger 110 in light of the repeated and rapid temperature variations to which it may be exposed.
[0040] Referring now to Figs. 6A-6E, schematic illustrations of the opposing piston assembly 105 of Fig. 4 A are shown with a movement sequence over time during operation. Indeed, Fig. 6A resembles Fig. 4A with the operating fluid, supercritical C02, within the first chamber 455 having attained sufficient pressure to drive the piston 400 a full stroke in the direction shown (see 600). Ultimately, this means that work may be directed toward a motor 200. For the embodiments herein, added timing and guidance may be provided through valving (e.g. see valve 475).
[0041] With an initial stroke completed, the second chamber 457 may be heated at the same time that the first chamber 455 is cooled (See Fig. 6B). As a result, the piston 400 may be held in place such that it builds more pressure or allowed to reverse course, stroking in the opposite direction (see arrow 600). Eventually, the piston 400 will reach the end of this stroke as well (see Fig. 6C). Notice that throughout the described stroking, the intermediate chambers 487 continue to circulate hydraulic oil with the motor 200 to effectively allow work to be obtained from the system.
[0042] As shown in Fig. 6D, with the piston 400 completing its stroke toward the first chamber 455, this chamber may once again be heated until a desired pressure is built and the piston driven back in the direction of the second chamber 457, which itself is cooled to further facilitate the process (see arrow 600). Eventually, the piston 400 will again reach the end of this stroke as shown in Fig. 6E, where it is returned to the position it occupied in Fig. 6A.
[0043] Referring now to Fig. 7, a flow-chart is shown which summarizes an embodiment of employing a thermal cycle engine utilizing closed loop dedicate heat exchangers. Namely, as indicated at 715 one heat exchanger in a closed loop with a chamber of a piston assembly is heated. Simultaneously, a second heat exchanger in a closed loop with an opposite chamber of the assembly is cooled (see 730). In this manner, a piston of the assembly is moved in a first direction as noted at 745. The process is then reversed with the first heat exchanger cooled as indicated at 760 and the second heat exchanger heated as indicated at 775. Thus, the piston is now moved in the opposite direction (see 785).
[0044] The preceding description has been presented with reference to presently preferred embodiments. Persons skilled in the art and technology to which these embodiments pertain will appreciate that alterations and changes in the described structures and methods of operation may be practiced without meaningfully departing from the principle and scope of these embodiments. Furthermore, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.

中文:
[0001]多年来,已经努力通过由不同热力学原理驱动的发动机获得了功或动力。例如,已经开发出依赖于“斯特林”或“有机朗肯”循环(ORC)的设备生成电力的技术。遗憾的是,这些技术在不要求极大升高温度的情况下通常无效以及效率低。例如,较低的热源,比如低于水的沸点的热源,基本上是无效的。
[0002]举例来说,ORC发动机制造商经常提供一种允许在输入热温低至170°F的情况下操作的系统。因此,例如,可以利用可能更容易地从液体状态变化到气体状态的制冷剂,其中涡轮机或类涡轮机技术对气体的气动力进行转换以生成生产性功。然而,通常也会获得显著降低的输出,从而使得该工作显著地降低了经济性。在某种程度上,这是由于ORC使用的工作流体的特性以及从工作流体机械获取功的范围和效率能力。
[0004]上面提到的ORC发动机将具有低沸点温度的液体转换成其气体状态,并且使气体或气体和液体混合物通过涡轮状装置以产生旋转运动。除了上述低效率之外,这种发动机以接近5,000rpm或更高的旋转速度操作。然后将气体混合物冷却回液体状态,在再次使用之前再次相变。即使不考虑低效率,这种速度和突然的相变也会产生与喷气式发动机相同的显著的噪音。
[0005]已经尝试过被称为“热液动热力发动机”的另一技术。该技术涉及使用施加至液体的热,该液体可以具有相对高的膨胀系数。然而,实际上,大多数液体在加热时膨胀很少,而且在冷却时收缩很少。因此,在实际操作中,这种发动机主要由于难以在液体中获得足够的膨胀和足够快的膨胀和收缩而未能取得成功的商业化。这限制了这种发动机的经济可行性。另外,即使在使用时,这种发动机也仅用于范围很窄的一组特定情况。这是因为对于不同用途的可行的修改而言,通常缺乏灵活性。实际上,即使在可以有效利用发动机的情况下,通常也需要大量的试验和错误。这部分地归因于与主要依赖于液体通过引入和移除热而膨胀和收缩的固有局限性。
[0007]图1是用于提供功的高动态密度范围的热循环发动机的实施方式的俯视图。
[0008]图2A是图1的热循环发动机的侧视图。
[0009]图2B是图1和图2的热循环发动机的相对侧的侧视图。
[0010]图3是图1的热循环发动机的发动机布局的示意图。
[0011]图4A是图1的发动机的相对的活塞组件的实施方式的示意图。
[0012]图4B是描绘提供基于图4A的活塞组件的膨胀和压缩轮廓的功输出的热循环的实施方式的曲线图。
[0013]图5A是图1的发动机的管板式热交换器的实施方式的一部分的透视图。
[0014]图5B是图5A的管板式热交换器的六边形构造的主视图。
[0015]图6A-6E是图4A的相对的活塞组件在操作期间随时间变化的移动顺序的示意图。
[0016]图7是概述采用利用封闭环路专用热交换器的热循环发动机的实施方式的流程图。
[0017]在以下描述中,阐述了许多细节以提供对本公开的理解。然而,本领域技术人员将理解,可以在没有这些特定细节的情况下实践所描述的实施方式。另外,可以采用许多变化或修改,这些变化或修改仍然如具体描述的实施方式所预期的那样。
[0018]本文详述的实施方式涉及一种控制封闭环路或容器内超临界流体形式的工作物质的膨胀和收缩的独特方式。具体地,工作物质的这种膨胀和收缩用于移动活塞以最终生成生产性功。当生成动力且马达附接至发电机时,发动机可以显示小于约50rpm的“低”转速。另外,本文详述的实施方式可以避免相变,并且因此本身具有更高的热力学效率,并且可以使用低于200°F的输入温度来有效地操作适当的操作流体。实际上,它们可以很容易地调整成在低于150°F的输入热量的情况下以较小的效率降低来操作。它还几乎无声地操作。然而,在其他实施方式中,可以使用替代的温度范围和不同的旋转速度,以及允许一定程度的流体相变。只要包含流体的室的加热和冷却由相同的热交换器控制,就可以实现明显的益处。
[0019]现在参考图1并额外参考图3,描绘了热循环发动机100的实施方式的俯视图。发动机100设置在滑道框架150上,其中发动机部件的主体以模块化方式牢固地保持。如上所述,提供仅与活塞组件105的一侧液压连通(也参见图2的活塞205)的专用热交换器110、120。也就是说,如图3的示意图所示,流体的封闭式储液器可以在热交换器110与活塞组件105的一侧处的室之间在专用线路309上循环。类似地,流体的另一封闭式储液器可以在其他热交换器120与活塞组件105的相对侧处的室之间在另一专用线路308上循环。
[0020]参考图1的俯视图,其他发动机部件是很明显的。例如,注意液压蓄能器180,该液压蓄能器180可以通过在岐管125处装设阀门而同步地工作,以周期性地向活塞冲程提供附加的力。液压储液器175也很明显。参考图3,该储液器175可以用作(或供应)热流体罐390或冷流体罐375。具体地,泵160可以用于使来自罐390和关联热源350的热水循环,以根据活塞组件105内的冲程运动的活塞的位置而在适当的时间加热适当的热交换器(110或120)。如上所述,在一种实施方式中,该水可以介于约150°F至约200°F之间。
[0021]出于同样的原因,可以使用另一泵(图1中不可见)在适当的时间将冷水从冷流体罐375和冷却源325循环到适当的热交换器(110或120)。在一种实施方式中,冷水是保持为约室温的水,可能来自邻近的水体。也就是说,不一定要求花费过度的能量来主动冷却该水。然而,在其他实施方式中,可以使用蒸发冷却器。
[0022]具体参考图3,并简要地附加参考图4A,值得注意的是,加热第一热交换器105的正时将与冷却第二热交换器120的正时一致,并且冷却第一热交换器105的正时将与加热第二热交换器120的正时一致。因此,当活塞组件105内的压力在第一室455处增加时,它在相对的第二室457内同时减小,从而增强活塞400的冲程运动(例如,如图4A所示的向下方向)。当然,在冲程的末端处,该过程随着第二热交换器120被加热、第一热交换器110被冷却、室455、457随着第二室457压力更高而在压差反转、以及活塞400沿相反方向行程(例如,如图4A所示向上)而被逆转。
[0023]回到图3,回想每个热交换器110、120配备有其自己的延伸至活塞组件105的专用线路307、308。具体地,参考图4A,从第一热交换器110延伸的专用线路307与组件105的第一室455流体连通。可替代地,来自第二热交换器120的专用线路308与第二室457流体连通。以这种方式,提供了两个单独的封闭环路液压系统,其中图4A的活塞400在连续的基础上在减小的容积和压力并且背离增大的容积和压力的方向上循环地冲程运动。然而,室与热交换器(例如455/110和457/120)之间的这些液压环路保持关闭。也就是说,从热水罐375或冷水罐390循环至热交换器110、120的流体不与所指出的封闭环路液压系统混合。作为代替,当经加热的水进入给定的交换器中时,适当选择的操作流体迅速从该交换器向外膨胀并且当经冷却的水进入时,操作流体迅速收缩回到该交换器中。还要注意,这种温度调节流体可以是水或在封闭环路系统内的不同类型的其他流体。相比之下,由于如下详述的独特膨胀特性,封闭环路系统可以利用超临界二氧化碳(CO2)作为操作流体。
[0024]所描述的热力循环可能是唯一有效的、高效地利用低于200°F的输入温度。实际上,可以调节循环以在低于150°F下操作而不会显著降低效率。因此,发动机100可以灵活利用许多可用的热源。例如,最终可以从低等级热源获得有用功,该热源诸如地热、太阳能热或来自其他不相关系统操作的废热。这允许有效且经济地利用先前被认为太冷并且没有实际经济价值的大量热源。
[0025]如下面详细描述的那样,在封闭环路中操作流体是CO2的情况下,将其保持在超临界或过热气体状态可能并不困难。因此,加热的应用增大了容积并实现了显著的膨胀,以便如上所述的那样增加压力并驱动活塞运动。另外,冷却该操作流体的应用促使其采用较小的容积,因此还促进了施加于与加热的室相对的室的活塞运动。如下面详细描述的,在操作流体能够在循环的基本持续时间内避免相变的情况下,该热循环特别有效。
[0026]现在参考图2A,示出了图1的热循环发动机100的侧视图。在该视图中,一些附加发动机部件是可见的。例如,框架容纳最初描绘的活塞组件105以及另一活塞组件205,以如下面所述的那样有效地使输出加倍。因此,例如,热交换器110可以控制包括有一个组件105的室455以及另一组件205的另一室的封闭环路(再次参见图4A)。沿着这些线路,如果需要,可以将许多附加活塞组件添加至发动机。无论如何,也如下面所讨论的,在所示的实施方式中,活塞组件105、205可以(可能在装设阀门的额外辅助下)同步循环。
[0027]除了如上文描述的液压储液器175、蓄能器180和岐管125,液压马达200在图2A中也是很明显的。具体地,来自热循环发动机100的功最终传递至马达200,在该马达200处该功最终可以用于生成和传输动力。
[0028]继续参考图2A,还示出了用于使热水和冷水循环进出热交换器110(和图1中的120)的各种液压力线路。更具体地,提供冷水供应线路280和回流线路220以及热水供应线路260和回流线路240。因此,实现适当的温度的水类型可以如上所述的在适当的时间循环到适当的热交换器110和120或从适当的热交换器110和120循环(参见图1)。
[0029]现在参考图2B,与图2A相比,从相反侧示出了发动机100。在该视图中,相同的水循环线220、240、260、280以及另一个热交换器120是很明显的。活塞组件105、205与蓄能器180也很明显。另外,示出了如上所述的用于使热水在适当的时间循环至适当的热交换器(110或120)的热泵160,以及用于使冷水在适当的时间循环至适当的热交换器(110或120)的冷泵260。
[0030]现在参考图3,示出了图1、图2A和图2B的热循环发动机100的发动机布局的示意图。如上所述,该发动机100最终以独特有效的方式促进来自马达200的功输出。这包括利用热交换器110、120的独特系统,其中每个交换器110、120独立地专用于泵组件105的一侧。这意味着每个交换器110、120限定并控制封闭液压环路,其中高温循环和低温循环都通过用于组件105的给定侧的相同的交换器110、120来管理。因此,经加热的输入(例如,从热源350和热水罐390)依次交替地施加至每个交换器110、120。同时,冷输入也(例如,从冷源325和冷水罐375)依次交替地施加至相对的交换器110、120。
[0031]继续参考图3,组件105内的往复活塞400使液压油循环通过岐管125,岐管125容纳定时地确保活塞400适当往复运动和正时的各种止回阀(见图4A)。实际上,岐管125也与指示的蓄能器180液压连通,该蓄能器180可以通过歧管125在活塞400不移动时周期性地充入或供应工作流体流或供应额外的压力返回,以促进活塞往复运动(例如,在活塞冲程的末端处)。另外,即使马达200本身也可能在活塞往复运动的正时中发挥作用。例如,马达200可以构造成以基本恒定的固定速度(可能低于约50rpm)来操作。除了有效且接近静音之外,这种类型的恒定固定移位可以通过岐管125液压连结返回,以进一步有助于调节活塞往复运动的速率。最终,可以实现非常受控且可靠同步的往复运动和输出的方式。
[0032]现在参考图4A,示出了图1的发动机100的相对的活塞组件105的实施方式的示意图。该图示揭示了组件105内的活塞400,该活塞400在室455、457之间往复运动,该室455、457本身是循环操作流体的独立封闭环路系统的一部分。在所示的实施方式中,操作流体是通常处于超临界状态的CO2,如下文所述。另外,当活塞400往复运动时,由中间封头440限定的中间室487用于使不可压缩的工作流体(诸如液压油)朝向一系列阀475并最终朝向如上所述的马达200循环。马达200可以是液压马达或甚至是曲轴,并且阀475可以模块化地并入岐管125中,如上文所描述的(参见图3)。以这种方式,循环的液压油可以提供可转移通过马达200的功。然后马达可以用于通过发电机产生电力。然而,泵、动力装置或压缩机也可以由马达驱动,或者液压动力甚至可以直接使用而不需要与马达进行任何连接。
[0033]在所示的实施方式中,中间室487由隔室480、485界定。这些隔室可以是充气隔室480、485,这些充气隔室用作工作流体室455、457与中间室487的液压油之间的密封缓冲区。阀475打开和关闭的时刻以及马达200的转速也有助于使该循环和活塞往复运动同步。例如,阀475可以在每次活塞接近每个冲程的末端时暂时关闭,以便驱使压力上升并帮助启动在相反方向上的冲程运动。这种正时可以由电子控制器调节。
[0034]现在参照图4B,示出了描绘提供功输出的热循环的实施方式的曲线图,该功输出基于图4A的活塞组件的膨胀和压缩轮廓。这种类型的曲线图可以称为P-v图。具体地,该曲线图显示了通过加热而增压的室(例如455)。这可以从(1)到(2)的移动看出,随着温度从大约100°F升高至略高于150°F,压力从约1,200psi上升至可能1,500psi以上。因此,室455中的压力作用于活塞头450并且随着活塞400沿向下方向移动而实现容积增大。注意到图4B中从(2)到(3)的移动反映了容积增大。注意到此时温度也开始略微下降。然而,从(3)到(4)的显著得多的下降是通过热交换技术由定制的引入冷却来实现的。具体地,在(4)处,温度已经从(3)处的略低于150°F变为低于约100°F。注意,这仍然高于88°F(该温度确保了CO2保持超临界状态)。因此,此时将促进活塞朝向该室455的移动,特别是按照依据上述描述的技术加热的另一室457的情况下。实际上,注意到随着从(4)回到(1)的移动,这个室455中的相应的容积减少。
[0035]在图4B的实施方式中,参考图4A,室455内的压力和温度组合维持在操作流体——在本示例中是CO2——保持在超临界状态的水平。这对于有效的操作不是必需的。然而,在热循环的基本持续时间内操作流体保持在超临界或过热气体状态的情况下,将获得更高的效率。更具体地,避免操作流体进入和离开液体或“致密”状态的过度相变可以提高效率。另外,利用这里详述的技术和设备设置,可以容易地基本在整个“相变圆顶”之外操作。
[0036]值得注意的是,对于替代的操作流体,可以采用许多不同的压力和温度范围来将流体维持在超临界或过热气体状态下达到该循环的基本持续时间。在所示的实施方式中,考虑到CO2允许相对低的热量和可控制的压力从而快速且容易地显示这些特性而使用CO2。但是,可以对其他流体类型进行建模和离散化。另外,根据本文描述的技术,可以在运行热循环中使用各种活塞尺寸和用于评估替代公差的其他变量。
[0037]现在参考图5A,示出了图1的发动机100的管板式热交换器110的实施方式的透视图。交换器110具有稳健的构造,该构造被定制成控制在如上文所述并如下文进一步描述的热循环期间放置在交换器上的快速加热应力源和快速冷却应力源。因此,所示的交换器110的部分可以容纳在厚壳体或双壁壳体中,该壳体能够承受连续且快速的加热和冷却的应力。在这方面,可以采用选择不锈钢或其他稳健的材料。
[0038]由于热交换器决定了热循环过程中能量增加和减少的量,所以图1的整个发动机100的尺寸设定首先从交换器110、120的尺寸设定开始。在图5A的实施方式中,管板式交换器110包括由对齐板525、575保持就位的多个微管500。与常规的交换器相反,所描绘的管板式交换器110没有操作流体通过。相反,交换器用作保持操作流体的储液器。因此,在施加如上所述的热时,流体快速膨胀,大部分离开交换器110,或者在施加冷却时,流体迅速收缩进入交换器110的较小容积(例如,如上文描述的)。流体类型不仅影响该过程的速率,而且交换器110的管状的性质也有效地显著增加了作用于操作流体的交换器110的表面区域。
[0039]特别参考图5B,图5A的管板式热交换器的六边形构造的主视图以六边形形式示出。管500的间隔可以由基于诸如管壁厚度之类的各种其他变量设定的预定间距(P)和直径(D)来限定。因此,例如,考虑到鉴于该热交换器110可能暴露于重复和快速温度变化中的持续性质,该特定值可能是重要的。
[0040]现在参考图6A-6E,示出了图4A的相对的活塞组件105在操作期间随时间变化的移动顺序的示意图。实际上,图6A类似于具有操作流体,即超临界CO2的图4A,在第一室455内已经获得足够的压力从而沿所示方向(见600)驱动活塞400进行一完整冲程。最终,这意味着功可以指向马达200。对于本文的实施方式,可以通过装设阀门(例如参见阀475)来提供额外的正时和引导。
[0041]在完成初始冲程的情况下,第二室457可以在第一室455被冷却的同时而被加热(参见图6B)。因此,活塞400可以保持就位,从而使其产生更大的压力或允许反向过程,沿相反方向(参见箭头600)进行冲程运动。最终,活塞400也将到达该冲程的末端(参见图6C)。注意,在所述冲程运动中,中间室487继续使用马达200对液压油进行循环,以有效地允许从系统获得功。
[0042]如图6D所示,在活塞400朝向第一室455完成其冲程的情况下,该室可以再次被加热,直到建立所需压力并且活塞沿第二室457的方向(见箭头600)驱动返回,该第二室457本身被冷却,以进一步促进该过程。最终,活塞400将再次到达该冲程的末端,如图6E所示,其中该活塞400返回到其在图6A中占据的位置。
[0043]现在参照图7,示出了一流程图,该流程图总结了采用利用封闭环路专用热交换器的热循环发动机的实施方式。即,如715处所示,加热带有活塞组件的室的封闭环路中的一个热交换器。同时,冷却带有组件的相对室的封闭环路中的第二热交换器(参见730)。以这种方式,组件的活塞沿第一方向移动,如745处所示。通过如760处所示的那样冷却该第一热交换器并且如第775所示的那样加热该第二热交换器,使该过程然后反向。因此,活塞现在沿相反方向移动(见785)。
[0044]已经参考目前的优选实施方式提出了前面的描述。这些实施方式所属领域的技术人员将理解,在不有意地脱离这些实施方式的原理和范围的情况下,可以实施所述结构和操作方法的改变和变化。此外,前面的描述不应该被理解为仅涉及随附附图中描述和示出的精确结构,而是应该被理解为与所附权利要求一致并且由所附权利要求支持,这些权利要求将具有其最充分的和最公平的范围。