Patent Application
20220235988
The present invention relates to the technique of refrigerant compressors, and more particularly, to refrigerant compressors using thermal energy as power source for the compression.
Heat pumps are commonly used in a variety of situations requiring the transfer of thermal energy between two paces. There are a variety of types of heat pumps including geothermal/water, geothermal/air, air/air etc. Each of these types uses different sources and sinks for the transfer of thermal energy.
Refrigerants used in heat pumps condense at various temperatures. Following condensation in a heat pump, the refrigerant often has only a slightly lower temperature than before condensation but has changed its physical state. For example, for a refrigerant having an evaporation temperature of 0° and a condensation temperature of 50°, this means the most optimal compression would result in a gas having exactly 50° and the saturation pressure corresponding to 50°. Temperatures above this correspond to unnecessary work. If one then lets the gas condense to liquid, it might have a temp of about 49°. If one assumes constant heat capacity over the range of 0 to 50, 49/50 of the work remains as heat.
By reusing this energy wisely, much can be gained. If this energy can be used to compress gas and do so with 100% efficiency, only a small amount of the original compression energy would be needed to compress new gas. If one were to use a regular heat engine, the maximum theoretical efficiency of a heat engine (which no engine ever attains) is equal to the temperature difference between the hot and cold ends divided by the temperature at the hot end, all expressed as absolute temperatures, which would approximately, using the temperatures above, render in a theoretical efficiency of about 15%.
A number of inventions cool down the refrigerant before the compressor to decrease the pressure of the refrigerant or possibly to increase the density and thus reduce the energy consumption of the compressor.
In U.S. Pat. No. 5,797,277, the refrigerant is cooled down by condensation from the evaporator in a heat exchanger that simultaneously cools the refrigerant condensed from the condenser. However, a pressure reduction of the refrigerant seems inevitable in this process. Furthermore, the gas is not superheated prior to the cooling, the cooling does not seem to be controlled as to recycle the energy whereby the compression isn't very energy efficient.
In U.S. Pat. No. 4,208,885 a transducer is used, which takes the expansion valve location, but also compresses the refrigerant out of the evaporator. The refrigerant that then flows towards the compressor can then be fed directly to the compressor or heat exchanged against refrigerant flowing from the condenser.
However, in neither of these patents it seems like the gas is consciously superheated solely for the purpose of applying pressure on cold gas and thereby compress it. None of the above patents shows a device where the refrigerant (after evaporator) is first heated, partly ejected into a compressor part, and then having non ejected gas cooled while at the same time recycling left energy. This behavior of the present invention solves the problem of getting low pressure gas entering the apparatus. Also, their only examples show cooling of evaporated gas, wherein the superheating of the gas tend to be very small, and therefore the pressure increase above saturated pressure is small.
To make the compression energy efficient it is recommended that cooling under pressure is done recycling the energy otherwise it won't render in energy efficient compression. To make the compression ratio large, a very large temperature increase is needed or several units working in series. None of the above show examples of such solutions.
One problem with the previously described solution in section is that it is difficult to inject low pressure gas into a high-pressure volume. Assume you have a sealed high pressure hot gas volume, applying pressure on a cold gas volume, compressing said cold gas volume. It can start to compress said cold gas volume, but when it loses its density it will have less pressure than the cold high-pressure destination, whereby it will not eject any gas into said flow. Neither will an evaporator add any gas into said hot high-pressure volume, since it has still quite high pressure.
Another problem with the previously described solution is that if you manage to achieve a volume of high pressure, it is difficult transfer that pressure to a different destination volume. For example, assume you have 2 containers, a source, and a destination, with the same volume, the source having a start pressure of 2 bar and the destination of 1 bar, whereby you would get something close to 1.5 bar in both containers when you connect them. Therefore, to keep the pressure high in the flow of the compressor part in previously described solution, you can only eject a small part of the superheated gas in the ejection part, to prevent it from decreasing in pressure. In theory this problem can be solved, since most of the energy is still in the non-ejected gas, which theoretically can be reused, to heat up new gas. Part of the solution is therefore an advanced heat exchanger unit for gas. In this solution, you often want to transfer energy from a refrigerant to a gas, gas to gas, and gas to refrigerant. This can be difficult, partly because hot gas has a higher pressure than cold gas and therefore cold gas will not flow towards hot gas, furthermore you might have to warm up the heat exchanger to heat the gas and this probably has greater mass than the gas.
Thus, there is a need for a system to address the problems discussed above.
The present invention is a system and method for using thermal energy to compress gas. The system of the present invention comprises a compressor chamber, a gas heating device, and a gradational heat transfer conduit. The method of the present invention comprises heating gas with the gas heating device to a high pressure, high temperature, and low density, then ejecting the heated gas into the gradational heat transfer conduit, cooling the heated gas as it passes through the gradational heat transfer conduit, and transferring the cooled gas to the compressor chamber with a low temperature, high pressure, and high density.
In some embodiments, movement of the gas through the gradational heat transfer conduit comprises a unidirectional flow. The unidirectional flow is cooled down in the flow direction by one or more heat exchangers, while hot gas at the same time applies pressure on the cold gas, whereby the density increases in the cooling direction.
In one preferred embodiment, the invention proposes an apparatus separated in two parts, a compressor part wherein hot gas applies pressure on cold gas and a second part comprising a heat exchanger unit for gas wherein gas is heated to a high pressure, whereafter it is ejected into said compressor part, whereafter thermal energy from non-ejected gas is recycled as described.
In some embodiments, the gas heating device comprises an apparatus that heats up cold gas while keeping it's density fairly stable, or in some cases increasing the density, wherein gas is heated to a high pressure, whereafter it is ejected into the gradational heat transfer conduit, whereafter thermal energy from non-ejected gas is recycled while cooling down said non ejected gas, whereby a volume cooled non ejected gas is either decreased in pressure, whereby new external gas with substantially the same temperature but with higher density can be absorbed into said volume. Or said cooled non ejected gas is decreased in volume whereby new external gas with substantially the same temperature and density can be injected in parallel to said volume. In this way hot gas can be constantly injected to the gradational heat transfer conduit.
Hence, according to the invention, the compressor chamber, gas heating device, and gradational heat transfer conduit, in combination, create a gas compressor system that receives cold gas of low pressure and eject slightly hotter gas of slightly higher pressure. The output from one gas compressor system can be injected into a second gas compressor system. The present invention can advantageously be implemented in several steps to become a gas compressor system that together can perform a large compression. Since it is suggested that thermal energy should be recycled as well as possible, both in the first and second part, recycled energy from one gas compressors system can be used as energy for another gas compressor system, and thereby you can get a large compression from a small energy.
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.
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.
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.
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.
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.
Referring to
The overall principle of the compressor system as shown in
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.
Referring to
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).
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
Referring to
Referring to
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.
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.
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.
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.
Referring to
The components of the rotating portion 400 of the gas heating device 4 are shown in
In use, the gas heating device 4 embodiment shown in
Referring to
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.
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
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.
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.
Referring to
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
Referring to
Referring to
In addition, it can be noted that in
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.
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
Note that it is advantageous to use previously described techniques, such as those shown in
Referring again to
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.
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.
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
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.
In use, Referring to
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
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.
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.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16327848 | Feb 2019 | US |
| Child | 17720026 | US |
