Systems and Methods for Compressing Gas Using Heat as Energy Source

[0038]As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art that the present disclosure has broad utility and application. As should be understood, any embodiment may incorporate only one or a plurality of the above-disclosed aspects of the disclosure and may further incorporate only one or a plurality of the above-disclosed features. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the embodiments of the present disclosure. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present disclosure.

[0039]Accordingly, while embodiments are described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present disclosure and are made merely for the purposes of providing a full and enabling disclosure. The detailed disclosure herein of one or more embodiments is not intended, nor is to be construed, to limit the scope of patent protection afforded in any claim of a patent issuing here from, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection be defined by reading into any claim limitation found herein and/or issuing here from that does not explicitly appear in the claim itself.

[0040]Thus, for example, any sequence(s) and/or temporal order of steps of various processes or methods that are described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal order, the steps of any such processes or methods are not limited to being carried out in any particular sequence or order, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and orders while still falling within the scope of the present disclosure. Accordingly, it is intended that the scope of patent protection is to be defined by the issued claim(s) rather than the description set forth herein.

[0041]The present invention is a compressor using heat as energy source. The present invention comprises a compressor chamber 3, a gas heating device 4, and a gradational heat transfer conduit 5. While the apparatus may be used as a standalone system for gas compression, it may also be used in conjunction with a traditional energy source to lower the work performed by a compressor. Generally, the solution presented by the present invention uses superheated high pressure hot gas to put pressure on cold gas. This can be accomplished by having cold gas on one side and by repeatedly injecting hot gas on the other, compressing the cold gas.

[0042]In some embodiments, this is accomplished through unidirectional flow, cooled down in the flow direction. This cooling is performed by the one or more heat exchangers 51 while keeping the pressure substantially constant. while at the same time preventing mixing between hot and cold gas performing inductive heat exchange within the flow. One benefit of this solution, compared to using a double acting compressor, is the simplicity, you get a constant flow without having to empty and fill said compressor. Another benefit is the energy efficiency as much of the heat transferred in the one or more heat exchangers 51 can be recycled to heat up new gas for the system.

[0043]Referring to FIG. 1, in general, the present invention comprises a hot end 1 and a cold end 2. The gas heating device 4 is located at the hot end 1 of the system, further comprising a heater chamber 41, a heater inlet 42, a heater outlet 43, and a heating portion 44. The compressor chamber 3 is located at the cold end 2 of the system, further comprising a compressor inlet 31, and a compressor outlet 32. Between the heater chamber 41 and the compressor chamber 3 is the gradational heat transfer conduit 5. The gradational heat transfer conduit 5 further comprises a first end 52, a second end 53, and one or more heat exchangers 51 arranged in series. The gradational heat transfer conduit 5 is configured to have a substantially unidirectional temperature gradient and substantially unidirectional gas flow from the hot end 1 to the cold end 2. It should be noted that the present invention may comprise more than one gradational heat transfer conduit 5 in various embodiments and configurations. In some embodiments, the gradational heat transfer conduit 5 is a singular apparatus.

[0044]The overall principle of the compressor system as shown in FIG. 1 is as follows. The heater chamber 41 contains a hot source quantity of gas, and the compressor chamber 3 contains a cold destination quantity of gas. The hot source quantity of gas is superheated so that it has a pressure notably higher than gas with the same density and a saturated temperature. Hypothermic flow of gas occurs is a substantially unidirectional flow from the heater chamber 41 to the compressor chamber 3, through the one or more heat exchangers 51. The gas experiences a drop in temperature, but little to no drop in pressure during this flow. Much of the energy dissipated to the one or more heat exchangers 51 can be regained and recycled to be used at a later stage. In the preferred embodiment, the gradational heat transfer conduit 5 and one or more heat exchangers 51 are configured to cool the gas close to the saturation temperature of the gas when it reaches the cold end 2 of the system.

[0045]In short, gas enters the gradational heat transfer conduit 5 from the heater chamber 41 with high pressure, high temperature and low density, and exits the gradational heat transfer conduit 5 to the compressor chamber 3 with high pressure, low temperature, and high density. Thus, gas has been compressed using the pressure of input heat. A large amount of the energy used to heat the gas to its superheated state can be recycled by the energy gained in the one or more heat exchangers 51. For example, the fluid used in the one or more heat exchangers 51 may be sent to gas heating device 4 by a heat recycling line 54.

[0046]Referring to FIG. 2, the system of the present invention is illustrated with regard to the flow of heat that may occur throughout the system during operation with an expanded view of the gas heating device 4. This figure is acts to show help illustrate the movement of heat and gas throughout the system and is only a single embodiment of the invention. In use Gas enters the device via an input 1.1, from an external source 1.0. The external source may be represented by an evaporator, outdoor air, another device or any other source that can supply a substantially constant pressured gas. The gas is then moved through the heater, passing by walls of gradually increasing temperatures until it reaches its maximum at position 1.5. There in the heater chamber 41, it now has a superheated temperature, and a superheated pressure notably higher pressure, than in 1.0. The heater-chamber 41 is then connected to the input of the gradational heat transfer conduit 5, having slightly lower pressure, applying pressure on the gas within the gradational heat transfer conduit 5. The cold end of the gradational heat transfer conduit connects to a compressor chamber 3, as part applying pressure on the gas within the compressor chamber 3, thereby transferring some of the pressure from the heater-chamber 41 to the compressor chamber 3. Hot, high-pressured gas enters the gradational heat transfer conduit at the hot end 1, and cold, high-pressured gas exits the conduit at the cold end 2. By cooling the gas in the gradational heat transfer conduit preferably in a counterflow manner, and more preferably using a liquid refrigerant, cooling the gas while trying to receive as high a temperature as possible at the output of the counterflow flow, a large amount of heat can be recycled and used to heat new gas (see 1.17-1.19).

[0047]After the heater-chamber 41 has connected to the gradational heat transfer conduit 5, for applying pressure on the gas withing the conduit, due to pressure equalization. The remaining gas within in the chamber 41, will have slightly dropped in temperature and pressure, due to expansion (illustrated by shaded volumes between 1.5 and 1.9). The heater chamber is then disconnected, having lower density. However, a significant amount of heat still remains, and can be used for heating gas in the gas heating device 4. This is represented in the drawing by gas volumes, being moved towards colder positions 1.6, 1.7, 1.8, (sparser stripes in the pattern representing lower density), while transferring heat to heated volumes (see 1.2, 1.3 and 1.4). After a volume of gas has cooled down to its initial temperature (equal to the source 1.0), it will have both low density and temperature (see ex 1.8). It will now easily be filled with new gas, when connected to an external source 1.0 (see ex 1.1 and 1.0).

[0048]The substantially unidirectional temperature gradient and gas flow in the in the gradational heat transfer conduit 5 may be achieved by the continuous supply of superheated gas from the heater chamber 41 to the gradational heat transfer conduit 5, which promotes flow from the hot end 1 to the cold end 2. Referring to FIG. 3, this substantially unidirectional gradient and flow can be promoted by the introduction of a plurality of one-way valves 501 in the gradational heat transfer conduit 5. These one-way valves 501 should have a very low cracking pressure. In one embodiment, the one-way valves 501 may be tesla valves to promote the unidirectional flow through the gradational heat transfer conduit 5.

[0049]Referring to FIG. 4, in an alternative embodiment, substantially unidirectional flow is achieved through the use of a plurality of narrow conduits 502 rather than a single larger conduit. In such an embodiment, the gradational heat transfer conduit 5 comprises a plurality of narrow passages. Using narrow passages in combination with a continuous supply of gas to the plurality of narrow passages promotes unidirectional flow and limits turbulation.

[0050]Referring to FIG. 5, in another alternative embodiment, the gradational heat transfer conduit 5 comprises a plurality of openable walls 503. In this embodiment, the plurality of openable walls 503 is arranged in series throughout the gradational heat transfer conduit 5. Each of the plurality of openable walls 503 may be opened individually to allow the gas on either side of the wall to mix. In use, each of the plurality of openable walls 503 is opened consecutively, starting with the one closest to the output and ending with the one closest to the input. Since the cold end 2 has slightly lower pressure than the hot end 1, the gas closest to the output will expand, thereby slightly losing pressure, so when the next openable wall opens it will also open towards a section that has had a chance of expanding. Due to this the gas will tend to expand towards the output.

[0051]Another way to achieve substantially unidirectional flow in the gradational heat transfer conduit 5 is to repetitively connect the first end 52 to heater chambers 41 with new and high pressure and repetitively connect the second end 53 to the compressor chamber. Doing so will ensure that the output has lower pressure than the input and will therefore promote unidirectional flow.

[0052]Each of the above referenced embodiments for achieving substantially unidirectional flow in the gradational heat transfer conduit 5 may be used individually or in combination with another embodiment. For example, the one-way valves 501 may be used within the plurality of narrow passages. Additionally, while referred to here in connection with the gradational heat transfer conduit 5, the above-referenced embodiments for achieving substantially unidirectional flow may be implemented in other pipe, conduits, chambers, etc., such as within the one or more heat exchangers 51.

[0053]The gas heating device 4 comprises a heater chamber 41, a heater inlet 42, a heater outlet 43, and a heating portion 44. Input gas enters the gas heating device to be heated by the heating portion 44 and ejected out the heater outlet 43. The heater outlet 43 is connected to the hot end 1 of the gradational heat transfer conduit 5, allowing for ejection of heated gas directly from the heater chamber 41 to the gradational heat transfer conduit 5. During ejection, a first volume of the heated gas is ejected to the gradational heat transfer conduit 5, while a second volume of the heated gas remains in the heater chamber 41. The heating portion 44 is configured to heat up the gas until it gets to a notably higher pressure than the input gas while maintaining as high a density as possible. The gas heating device 4 may further comprise a cooling portion 45 configured to cool the second volume of the heated gas after ejection to allow for addition of new, low-pressure gas to the gas heating device 4.

[0054]In one embodiment of the gas heating device 4, it is preferred that the heating portion 44 heats up the gas, using other warm refrigerant, bringing the gas as close to the maximum temperature of the warm refrigerant as possible, while stealing as little energy as possible from the other warm refrigerant, also while keeping the density of the heated gas as high as possible. In such an embodiment, the cooling portion 45 may cool down subparts of the heated gas within the gas heating device 4, after other subparts of the heated gas have been ejected into the gradational heat transfer conduit 5, using cold refrigerant, bringing the cold refrigerant temperature as close to the warm gas maximum temperature as possible, while stealing as little energy as possible from the warm gas, getting as low output pressure of the cooled gas as possible.

[0055]Referring to FIG. 6, in one embodiment, the gas heating device 4 may comprise a plurality of heater inlets 401, a plurality of heater outlets 402, and a plurality of heater chambers 403 in addition to the heating portion 44 and the cooling portion 45. The plurality of heater chambers 403 may be arranged radially in a rotating portion and configured to move around a central axis 404 while the plurality of heater inlets 401 and plurality of heater outlets 402 remain stationary, configured to connect to each of the plurality of heater chambers 403 sequentially as they move. In such an embodiment, new external gas enters the plurality of heater chambers 403 through the plurality of heater inlets 401, the gas is heated by the heating portion 44 as the plurality of heater chambers 403 move toward the plurality of heater outlets 402. Once each of the plurality of heater chambers 403 reaches one of the plurality of heater outlets 402, the first volume of gas is ejected from the heater chamber 41 out the heater outlet 43, while the second volume of gas remains in the heater chamber 41. This applies for each of the plurality of heater chambers 403 passing by each of the plurality of heater outlets 402, meaning that each of the plurality of heater chambers 403 ejects lesser and lesser pressure for each of the plurality of heater outlets 402 it passes. The second volume of gas in each of the plurality of heater chambers 403 is cooled by the cooling portion 45 as it moves back toward the plurality of heater inlets 401. Once each of the plurality of heater chambers 403 reaches the plurality of heater inlets 401, the cycle begins again with introduction of new external gas.

[0056]The components of the rotating portion 400 of the gas heating device 4 are shown in FIG. 6. The rotating portion comprises a base 405, a plurality of walls 406, and a lid 407. The plurality of walls 406 fits within the base 405 and is sealingly covered by the lid 407, creating the plurality of heater chambers 403 within the rotating portion 400. The plurality of walls 406 is ideally made of a light and highly insulating material to prevent heat transfer between the plurality of heater chambers 403. Referring to FIG. 6, the heating portion 44 and the cooling portion 45 may be operated by the transfer of hot and cold refrigerants from one or more refrigerant reservoirs 408, through a plurality of refrigerant lines 409. The refrigerant lines 409 are arranged against the rotating portion of the gas heating device 4 and configured to provide and remove heat from specific areas of the rotating portion. The refrigerant lines 409 are shown in FIG. 7 to run behind the rotating portion in contact with the base 405 of the rotating portion, however, the plurality of refrigerant lines 409 may also run along the lid 407 of the rotating portion.

[0057]In use, the gas heating device 4 embodiment shown in FIG. 6 operates as follows. Input gas enters the gas heating device 4 through the plurality of heater inlets 401. Each of the plurality of heater inlets 401 may be associated with a different pressure. In FIG. 7, the first input (i1) contains the highest pressure with the pressure decreasing sequentially, i.e. (i8) has the lowest pressure, and in between there will be different pressures, varying between the lowest and the highest. The rotating portion 400 moves clockwise one step at a time, allowing each of the plurality of heater chambers 403 to pass from position A to position H, taking in incrementally higher-pressure gas from a different heater inlet 42 at each position. The plurality of heater chambers 403 is then heated while moving from position Ito P, the gas incrementally increasing in temperature and/or pressure. The plurality of refrigerant lines 409 running along this area of the rotating portion transfer heat to the rotating portion. The refrigerant temperature and specific arrangement of refrigerant lines 409 may be adjusted to achieve preferred heating within this section of the rotating portion. After heating, the gas is ejected through the plurality of heater outlets 402. Each of the heater outlets 402 may be associated with a different pressure. In FIG. 7, the first output (o1) receives the highest pressure with the pressure decreasing further to the right. Thus, as the plurality of heater chambers 403 advance from position Q to X, a portion of the gas is ejected through each of the plurality of heater outlets 402, with the remaining gas in the heater chamber 41 reducing in pressure with each ejection. Finally, the plurality of heater chambers 403 is then cooled while moving from position Y to FF, the gas incrementally decreasing in temperature and/or pressure. The plurality of refrigerant lines 409 running along this area of the rotating portion remove heat from the rotating portion. The refrigerant temperature and specific arrangement of refrigerant lines 409 may be adjusted to achieve preferred cooling within this section of the rotating portion. This cooling allows the remaining non-ejected gas to be compatible in pressure with the gas entering the plurality of heater chambers 403 through the plurality of heater inlets 401 at positions A through H.

[0058]Referring to FIG. 9, multiple gas heating devices 4 may be connected in series. Through the use of multiple gas heating devices 4 and multiple gradational heat transfer conduits 5, the compression ratio of the compressor may be the product of the compression ratios from each gas heating device 4. Additionally, refrigerant can be recycled between gas heating devices 4, making for a more efficient overall use of thermal energy.

[0059]Note, however, that the chambers in the following gas heating device 4 should be smaller than those in the previous one so that the compression achieved is not wasted. Furthermore, it can be seen at the inflow of the subsequent gas heating device 4 that, each cooled heater chamber will be sequentially connected to outflows, from the prior gas heating device, of different pressures, and does so in order of incrementally increasing pressure.

[0060]In the above manner incremental compression is achieved, i.e., a gas volume starting with a low pressure isn't compressed with gas of maximum pressure directly, instead said low pressure gas volume is compressed, in sequence, by gas volumes with incrementally higher pressure, preferably only slightly higher than the low-pressure gas volumes momentary pressure. This means less work is done by the volumes of higher pressure, meaning the work resembles the graph in FIG. 8c, instead of the graph in FIG. 8b. The more increments used, and the closer they are in pressure, compared to the destination, the closer the work gets to the graph of the optimal work described in FIG. 8a.

[0061]The above device/method for transferring more gas to higher pressure, from a source-gas chamber to a destination-gas chamber, is here called pressure-transfer-device/pressure-transfer-method.

[0062]The system of the present invention may further comprise a pressure transfer device 6 between the gas heating device 4 and the compressor chamber 3 or between one gas heating device 4 and a second gas heating device 4. The pressure transfer device 6 may be fully contained within the gradational heat transfer conduit 5 or may otherwise connected in series with the gradational heat transfer conduit 5. The pressure transfer device 6 more efficiently equalizes the pressure difference between the gas ejected from the gas heating device 4 and the gas already present in the gradational heat transfer conduit 5 or compressor chamber 3, allowing more superheated gas from the gas heating device 4 to be ejected in each transfer, thereby increasing the volume of the first volume of gas in the heater chamber 41 to be ejected and reducing the volume of the second volume of gas in the heater chamber 41 to be cooled and reused. In sum, improved pressure transfer can be achieved by connecting two chambers of different pressures by way of a parallel array of intermediate chambers of decreasing pressure rather than a single chamber.

[0063]Referring to FIG. 10, the pressure transfer device 6 comprises an input coupling device 61, an output coupling device 62, and a plurality of pressure chambers 63. Each of the plurality of pressure chambers 63 has a high-pressure end 64 and a low-pressure end 65. The plurality of pressure chambers acts as chambers of varying intermediate pressures. The input coupling device 61 connects the heater outlet 43 of the gas heating device 4 to the plurality of pressure chambers 63 of the pressure transfer device 6. The input coupling device 61 is selectably fluidly coupled with the high-pressure end 64 of each of the plurality of pressure chambers 63. The output coupling device 62 selectably fluidly couples the low-pressure end 65 of each of the plurality of pressure chambers 63 to the gradational heat transfer conduit 5 or directly to the compressor inlet 31. In use, the high-pressure gas from the gas heating device 4 enters the input coupling device 61 and is distributed to each of the plurality of pressure chambers 63 one at a time, resulting in each pressure chamber having a volume of gas with a pressure less than that of the preceding pressure chamber. Once the gas is distributed among the plurality of pressure chambers 63, each of the pressure chambers 63 is connected to the output coupling device 62, one at a time, in the opposite order that they were filled by the input coupling device 61. For example, in an embodiment of the pressure transfer device 6 with three pressure chambers 63, the input coupling device 61 couples with a first pressure chamber, filling it with a first volume of gas with a high pressure, then couples with a second pressure chamber, filling it with a second volume of gas with a medium pressure, then couples with a third pressure chamber, filling it with a third volume of gas with a low pressure. The output coupling device 62 then couples with the third pressure chamber, removing the third volume of gas, then couples with the second pressure chamber, removing the second volume of gas, then couples with the first cooling compressor, removing the first volume of gas. It should be noted that even the “low-pressure” third volume of gas in this example has a higher pressure than the gas present in the gradational heat transfer conduit 5 prior to pressure transfer. This process is additionally illustrated in FIGS. 11 and 12.

[0064]A benefit of using the pressure transfer device 6, is that compressing a destination volume with incrementally increasing pressure is more energy efficient. If, for example, a large volume of high-pressure gas (Ex. 2 Bar) is to be discharged into a small volume of low-pressure gas (Ex. 1 Bar), the work performed could be represented by the graph in FIG. 8b, while total needed work is represented by FIG. 8a only. By compressing the destination volume in 4 steps, the work is represented by FIG. 8c, which is an improvement compared to FIG. 7b.

[0065]Referring to FIG. 9, in one embodiment of the present invention, the pressure transfer device 6 is integrated between a first gas heating device 411 and a second gas heating device 412. In such an embodiment, the plurality of heater outlets 402 of the first gas heating device 411 connect to the plurality of heater inlets 402 of the second heating device 412 by way of the pressure transfer device 6.

[0066]Referring to FIG. 13-14, in one embodiment of the present invention, the cold end 2 of the compressor system further comprises a cold pump 701 and a cold piston 702, and the hot end 1 of the compressor system further comprising a hot pump 703 and a hot piston 704, wherein the cold piston 702 and the hot piston 704 are interconnected and move synchronously. In this embodiment, the cold end 2 and the hot end 1 are connected by the one or more heat exchangers 51. The gradational heat transfer conduit 5 in this embodiment is combined with the pressure transfer device 6, in that the plurality of parallel heat transfer conduits 5 act as the pressure chambers for the pressure transfer device 6, allowing for the superheated gas to be cooled by the one or more heat exchangers 51 while traversing the pressure chambers 63 of the pressure transfer device 6. The hot pump 703 and the hot piston 704 are contained within the gas heating device 4 of the present invention.

[0067]In addition, it can be noted that in FIG. 1, the heating portion 44 of the gas heating device 4, responsible for heating the gas on its way to the heater-chamber, is integrated with the cooling of the gradational heat transfer conduit 5. This is not necessary but provides the possibility to directly use recycled heat from the cooling for heating new gas.

[0068]In use, input gas enters the system at the cold end 2. The first and second side of both the hot pump 703 and the cold pump 701 may then be connected, pumping a first volume of gas from a first side of the cold piston 702 to a second side of the cold piston 702 and simultaneously pumping a second volume of gas from the first side of the hot piston 704 to the second side of the hot piston 704. The first side and the second side of both the hot pump 703 and the cold pump 701 are then disconnected. The second side of the hot piston 704 then connected to the pressure transfer device 6 at the heater outlet 43. Decreased pressure from gas flow into the pressure transfer device 6 enforces compression of the gas on the second side of the cold piston 702.

[0069]The hot pump 703 and cold pump 701 stabilized at a position where the pressure difference between first side and second side of the cold pump 701 equals the pressure difference between the first side and second side of the hot pump 703. When the passages are open between the second side of cold piston 702 and the first side of the hot piston 704 with equal pressure within this domain, movement of gas from the cold end 2 into the one of more heat exchangers 51, and movement of gas from the one or more heat exchangers 51 into the hot end 1 can occur without added work. Referring to FIG. 14, note that the compressor chamber 3 is being compressed by gas of increasing pressure, since the output of the pressure transfer device connects the compressor chamber 3 to gradational heat transfer conduits 5 of increasing pressures. To reinforce this movement of gas through the one or more heat exchangers 51, a physical rectifier may be implemented on the cold piston 702 and/or the hot piston 704, prohibiting movement in the backward direction. The rectifier may be further configured to be deactivated or to switch from one side of a piston to the other in order for the pistons to move in the opposite direction.

[0070]Note that it is advantageous to use previously described techniques, such as those shown in FIG. 3-5, to achieve unidirectional flow even when heating. As with cooling, they can be used separately or in combination in order to achieve the preferred results. In particular, the technique of FIG. 5, wherein a plurality of walls 503 separate warmer and colder parts of a conduit in the heat exchanger, whereafter they open step by step, in order by their distance from the outlet. Starting closest to the outlet (in this case in the hottest part) and ending closest to the entrance (in this case in the coldest part). Thereafter they are closed step by step in the opposite order, i.e., starting closest to the heat exchanger input (in this case in the coldest part) and ending closest to the outlet (in this case in the hottest part). Advantages of this technique are that it does not have cracking pressure, and can handle large pressure differences.

[0071]Referring again to FIG. 5, in such an alternative embodiment, the gradational heat transfer conduit 5 includes a plurality of openable walls 503. In such an embodiment, the plurality of openable walls 503 are arranged in series throughout the channels of the gradual heating member. Each of the plurality of openable walls 503 can be opened individually to allow the gas on each side of the wall to mix. In use, each of the plurality of openable walls 503 is opened in succession, beginning with the nearest exit, and ending with the nearest entrance. Since the hot end 1 closest to the outlet opens first, the gas there can expand and thereby drop the pressure slightly, so when the next openable wall opens towards a warmer section which has had a chance to expand, it is more likely that it initially has a greater pressure. Due to this, the gas will tend to expand towards the outlet.

[0072]As the second volume of gas passes through the pressure transfer device 6 and the gradational heat transfer conduit 5, it is cooled by a counterflow of the first volume of gas through the heat exchanger from the cold end 2 to the hot end 1. The second volume of gas reaches the compressor chamber 3 through the compressor inlet 31 after passing through the pressure transfer device 6 and gradational heat transfer conduit 5. At this point, the first volume of gas becomes the second volume of gas for the next cycle as a new first volume of gas enters the system at the cold end 2.

[0073]In the one or more heat exchangers 51 of this embodiment, it is advantageous if the heated gas to be substantially moving unidirectionally towards the hot end 1. To enforce this, the same techniques can be used here, as in gradational heat transfer conduit 5. For example, openable walls 503, opening in sequential order, may be used within the one or more heat exchangers 51. In the embodiment using openable walls 503, the openable walls 503 in the one or more heat exchangers 51 may be the same openable walls 503 used in the gradational heat transfer conduit 5 or otherwise connected to the openable walls used in the gradational heat transfer conduit 5 where the openable walls 503 in the one or more heat exchangers 51 open in the opposite order as those in the gradational heat transfer conduit 5 starting with the one closest to the input and ending with the one closest to the output. Through this embodiment, the same set of openable walls 503 can promote substantially unidirectional flow in opposite directions in the one or more heat exchangers 51 and the gradational heat transfer conduit 5 respectively.

[0074]In the embodiment described in the preceding paragraphs, the hot pump 703 may comprise a plurality of hot subpumps 801 with a combined volume equal to that of the cold pump. This embodiment may additionally comprise a plurality of hot pistons 802 associated with the plurality of hot subpumps, as well as a plurality of pressure transfer devices 803. Such an embodiment is shown in FIG. 15. Increased efficiency in heating can be achieved by incremental gas transfer in this manner.

[0075]Each of the plurality of hot subpumps 801 can also use the one single pressure transfer device 6, wherein each of the plurality of hot subpumps 801 connects its output to the pressure transfer device 6 that then runs through the same process for each subpump. It should however be noted, that in this case, when a subpump has been connected to a conduit with minimum pressure, it should be connect to that conduit, via some other connection than the input coupling device, otherwise the following subpump will be directly connect to the final conduit, which is not intended.

[0076]In use, Referring to FIG. 15, input gas enters the system at the cold end 2. The hot pump 703 and the cold pump 701 may then be activated, pumping a first volume of gas from a first side of the cold piston 702 to a second side of the cold piston 702 and simultaneously pumping a second volume of gas from the first side of the plurality of hot pistons 802 to the second side of the hot piston 804. The second side of the first hot piston 8041 then connected to the pressure transfer device 6 at a first heater outlet 431, while the two sides of the remaining hot subpumps 801 remain connected. Decreased pressure from gas flow into the pressure transfer device 6 enforces compression of the gas on the second side of the cold piston 702. In order, one by one, the two sides of remaining hot subpumps 801 will be disconnected from each other and connected to pressure transfer device, each time further enforcing compression of the gas on the second side of the cold piston 702. Once all right sides of the hot subpumps 801 are connected to the gradational heat transfer conduit 5, with a pressure equal to the input of the cold pump the cold piston 701 stabilizes at the same position as the previous embodiment. However, smaller total volumes have been connected to pressure transfer device 6, ending up with same final low pressure, thus, initially, less gas is entering the cold pump than existing the hot subpumps 801. In running through several cycles, an increased density at the output of the heating device is generated. The increased density will further increase the pressure of the input of the hot subpumps 801, further enforcing compression of the gas on the second side of the cold piston 702. Over the course of several cycles, the average amount of gas entering the system must equal the amount exiting. As for previous embodiment, when the second volume of gas, in this case for each hot subpumps 801, passes through the pressure transfer device 6 and the gradational heat transfer conduit 5, it is cooled by a counterflow of the first volume of gas through the one or more heat exchangers 51 from the cold end 2 to the hot end 1. The second volume of gas reaches the compressor chamber 3 through the compressor inlet 31 after passing through the pressure transfer device 6 and gradational heat transfer conduit 5. At this point, the first volume of gas becomes the second volume of gas for the next cycle as a new first volume of gas enters the system at the cold end 2.

[0077]Each of the embodiments discussed above may further comprise additional heating elements for heating gas before it enters the gas heating device 4, while in the gas heating device 4, or before entering the gas heating device 4 from the recycling line 54. For example, the embodiment shown in FIG. 12 may further include a heating element beyond the gas heating device 4 to heat gas on the hot end 1 of the system.

[0078]It should also be noted that the embodiments above utilizing pumps can be coupled in series of several compressor device according to the embodiments, such that compressed gas from one compressor device can enter a subsequent compressor device to further compress the gas. One benefit of compressing by heating followed by cooling, is that recycled heat can be used again for the same gas, so long as the recycled heat has significantly higher temperature than the compressed gas. If heat is recycled efficiently, external heat only needs to be added to account for the amount not being recycled.

[0079]FIG. 16 is a flowchart of a method 1000 of compressing gas. Accordingly, at 1002, 1000 may include heating, using a gas heating device, a gas to an increased temperature and pressure. Further, at 1004, the method 1000 may include ejecting, using a heater outlet, the gas from the gas heating device to a first end of a gradational heat transfer conduit. Further, at 1006, 1000 may include cooling, using one or more heat exchangers, the gas to a cooled temperature. Further, at 1008, 1000 may include transferring, using a compressor inlet, the gas to a compressor chamber.

[0080]FIG. 17 is a flowchart of a method 2000 of managing gas flow as part of the method of compressing gas. Accordingly, at 2002, 2000 may include promoting, using the gradational heat transfer conduit, unidirectional gas flow from the first end of the gradational heat transfer conduit to a second end of the gradational heat transfer conduit. Further, at 2004, the method 2000 may include transferring, using a recycling line, heat from the one or more heat exchangers to the gas heating device.

[0081]FIG. 18 is a flowchart of a method 3000 of directing gas through the pressure transfer device as part of the method of compressing gas. Accordingly, at 3002, 3000 may include sequentially directing, using the input coupling device, incrementally lower-pressure gas into the plurality of pressure chambers. Further, at 3004, the method 3000 may include sequentially expelling, using the output coupling device, incrementally higher-pressure gas from the plurality of pressure chambers.

[0082]FIG. 19 is a flowchart of a method 4000 of heating and cooling gas as part of the method of compressing gas. Accordingly, at 4002, 4000 may include providing, using one or more refrigerant reservoirs, refrigerant to the heating portion and the cooling portion. Further, at 4004, the method 4000 may include providing heat, using the heating portion, to the gas. Further, at 4006, 4000 may include removing heat, using the cooling portion, from the gas.

[0083]FIG. 20 is a flowchart of a method 5000 of operating pumps as part of the method of compressing gas. Accordingly, at 5002, 5000 may include pumping, using a hot pump, gas across a hot piston. Further, at 5004, the method 5000 may include pumping, using a cold pump, gas across a cold piston.

[0084]Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.