Method for operating an adsorption compressor and adsorption compressor for use in said method
10132531 ยท 2018-11-20
Assignee
Inventors
Cpc classification
Y02A30/27
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F25B2500/01
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Y02B30/00
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
F25B17/083
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B35/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F25B17/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B25/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B17/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F25B15/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
The present invention is directed to a method of operating an adsorption compressor system, which system comprises a hot source and a cold source and at least a first and a second adsorption bed, wherein the first bed has an initial temperature that is lower than the initial temperature of said second bed, in which system heat is circulated using a heat transfer fluid (HTF), the method comprising the following phases: phase A) comprising the steps of: heating the first adsorption bed by feeding HTF to it, coming from said second bed, optionally via said hot source, while maintaining a thermal wave in said first bed; and cooling the second adsorption bed by feeding HTF to it, coming from said first bed, optionally via said cold source, while maintaining a thermal wave in said second bed; wherein phase A) is maintained until the exit temperature of said first bed and said second bed are essentially the same and phase B) comprising the steps of: feeding the HTF effluent of said first bed to said hot source and from said hot source back into said first bed; and feeding the HTF effluent of said second bed to said cold source and from said cold source back into said second bed; wherein phase B) is maintained until the temperature in said first bed is essentially homogeneous and the temperature in said second bed is also essentially homogeneous and lower than the temperature of said first bed, wherein the flow rates of said HTF through said first and second bed may be higher than in phase A).
Claims
1. A method of operating an adsorption compressor system including: at least one elongate first adsorption bed, at least one elongate second adsorption bed, a refrigerant circuit including an evaporator and a condenser, wherein the first adsorption bed and the second adsorption bed are part of the refrigerant circuit, a heat transfer fluid circuit that is separate from the refrigerant circuit and that includes: a hot source, a cold source, at least an elongate first heat transfer fluid channel that extends along the first adsorption bed and is in direct heat transferring contact with the first adsorption bed, at least an elongate second heat transfer fluid channel that extends along the second adsorption bed and is in direct heat transferring contact with the second adsorption bed, and heat transfer fluid control valves for controlling the direction of a flow of heat transfer fluid through the hot source, the cold source, the first heat transfer fluid channel and the second heat transfer fluid channel of the heat transfer fluid circuit, wherein, starting from a situation in which the first adsorption bed has an initial temperature that is lower than an initial temperature of the second adsorption bed, the method comprises the following phases A, B, C and D which are subsequently executed: Phase A comprising: controlling the heat transfer control valves to direct the heat transfer fluid subsequently through the second heat transfer fluid channel, the hot source and the first heat transfer fluid channel, the cold source and back to the second heat transfer fluid channel to heat the first adsorption bed by means of a thermal wave in the first adsorption bed and to cool the second adsorption bed by means of a thermal wave in the second adsorption bed; and maintaining Phase A until an exit temperature of the heat transfer fluid effluent leaving the first heat transfer channel and an exit temperature of the heat transfer fluid effluent leaving the second heat transfer channel are essentially the same; Phase B comprising: controlling the heat transfer fluid control valves to direct a first flow of heat transfer fluid subsequently through the first heat transfer fluid channel, the hot source and back into the first heat transfer fluid channel to further heat the first adsorption bed, and to direct a second flow of heat transfer fluid subsequently through the second heat transfer fluid channel, the cold source and back into the second heat transfer fluid channel for further cooling the second adsorption bed; and maintaining Phase B until a temperature in the first adsorption bed is essentially homogeneous and a temperature in the second adsorption bed is also essentially homogeneous and lower than the temperature of the first adsorption bed, Phase C comprising: controlling the heat transfer control valves to direct the heat transfer fluid subsequently through the first heat transfer fluid channel, the hot source and the second heat transfer fluid channel, the cold source and back to the first heat transfer fluid channel to cool the first adsorption bed by means of a thermal wave in the first adsorption bed and to heat the second adsorption bed by means of a thermal wave in the second adsorption bed; and maintaining Phase C until an exit temperature of the heat transfer fluid effluent leaving the first heat transfer channel and an exit temperature of the heat transfer fluid effluent leaving the second heat transfer channel are essentially the same; and Phase D comprising: controlling the heat transfer fluid control valves to direct a first flow of heat transfer fluid subsequently through the first heat transfer fluid channel, the cold source and back into the first heat transfer fluid channel to further cool the first adsorption bed, and to direct a second flow of heat transfer fluid subsequently through the second heat transfer fluid channel, the hot source and back into the second heat transfer fluid channel to further heat the second adsorption bed; and maintaining Phase D until a temperature in the first adsorption bed is essentially homogeneous and a temperature in the second adsorption bed is also essentially homogeneous and higher than the temperature of the first adsorption bed, the method further comprising: keeping a direction of flow of the heat transfer fluid through the first heat transfer channel and the second heat transfer channel the same in phases A and C.
2. The method according to claim 1, including: keeping the direction of flow through the first heat transfer channel and through the second heat transfer channel the same in phases A, B, C and D.
3. An adsorption compressor system comprising: at least one elongate first adsorption bed, at least one elongate second adsorption bed, a refrigerant circuit including an evaporator and a condenser, wherein the first adsorption bed and the second adsorption bed are part of the refrigerant circuit, a heat transfer fluid circuit that is separate from the refrigerant circuit and that includes: a heater forming hot source, a cooler forming cold source, at least an elongate first heat transfer fluid channel that extends along the first adsorption bed and is in direct heat transferring contact with the first adsorption bed, at least an elongate second heat transfer fluid channel that extends along the second adsorption bed and is in direct heat transferring contact with the second adsorption bed, and heat transfer fluid control valves for controlling the direction of a flow of heat transfer fluid through the hot source, the cold source, the first heat transfer fluid channel and the second heat transfer fluid channel of the heat transfer fluid circuit, and a controller for controlling the heat transfer fluid control valves and that is configured to subsequently execute phases A, B, C and D: Phase A comprising: controlling the heat transfer control valves to direct the heat transfer fluid subsequently through the second heat transfer fluid channel, the hot source and the first heat transfer fluid channel, the cold source and back to the second heat transfer fluid channel to heat the first adsorption bed by means of a thermal wave in the first adsorption bed and to cool the second adsorption bed by means of a thermal wave in the second adsorption bed, maintaining Phase A until an exit temperature of the heat transfer fluid effluent leaving the first heat transfer channel and an exit temperature of the heat transfer fluid effluent leaving the second heat transfer channel are essentially the same; Phase B comprising: controlling the heat transfer fluid control valves to direct a first flow of heat transfer fluid subsequently through the first heat transfer fluid channel, the hot source and back into the first heat transfer fluid channel to further heat the first adsorption bed, and to direct a second flow of heat transfer fluid subsequently through the second heat transfer fluid channel, the cold source and back into the second heat transfer fluid channel for further cooling the second adsorption bed; maintaining Phase B until a temperature in the first adsorption bed is essentially homogeneous and a temperature in the second adsorption bed is also essentially homogeneous and lower than the temperature of the first adsorption bed, Phase C comprising: controlling the heat transfer control valves to direct the heat transfer fluid subsequently through the first heat transfer fluid channel, the hot source and the second heat transfer fluid channel, the cold source and back to the first heat transfer fluid channel to cool the first adsorption bed by means of a thermal wave in the first adsorption bed and to heat the second adsorption bed by means of a thermal wave in the second adsorption bed, maintaining Phase C until an exit temperature of the heat transfer fluid effluent leaving the first heat transfer channel and an exit temperature of the heat transfer fluid effluent leaving the second heat transfer channel are essentially the same; and Phase D comprising: controlling the heat transfer fluid control valves to direct a first flow of heat transfer fluid subsequently through the first heat transfer fluid channel, the cold source and back into the first heat transfer fluid channel to further cool the first adsorption bed, and to direct a second flow of heat transfer fluid subsequently through the second heat transfer fluid channel, the hot source and back into the second heat transfer fluid channel to further heat the second adsorption bed; maintaining Phase D until a temperature in the d first adsorption bed is essentially homogeneous and a temperature in the second adsorption bed is also essentially homogeneous and higher than the temperature of the first adsorption bed, wherein a direction of flow of the heat transfer fluid through the first heat transfer channel and the second heat transfer channel is the same in phases A and C.
4. The adsorption compressor according to claim 3, further including: heat transfer fluid distribution connectors or heat transfer fluid headers provided at a first side and a second side of each of the first heat transfer fluid channel and the second heat transfer fluid channel, wherein the heat transfer fluid distribution connectors or the heat transfer fluid headers are each provided with a T-connector or two separate connectors, wherein the heat transfer fluid control valves include a first pair of three way valves and a second pair of three way valves, wherein each arm of the T-connectors or two separate connectors of the first side of each of the first heat transfer fluid channel and the second heat transfer fluid channel are in fluid connection with a switching side of a different three way valve of the first pair of three way valves, and wherein each arm of the T-connectors or the two separate connectors of the second side of each of the first heat transfer fluid channel and the second heat transfer fluid channel are in fluid connection with a switching side of a different three way valve of the second pair of three way valves.
5. The adsorption compressor according to claim 4, wherein a base side of the first three way valve of the first pair of three way valves and a base side of a first three way valve of the second pair of three way valves are in fluid connection with the heater and wherein a base side of the second three way valve of the first pair of three way valves and a base side of a second three way valve of the second pair of three way valves are in fluid connection with the cooler.
Description
(1) In order to further elucidate the invention, exemplary embodiments will be described with reference to the drawings. In the drawings:
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(49) The expression effective thermal conductivity used herein is to be understood as, though not to be considered limited to the thermal conductivity [W/mK] in the dominant heat transfer direction. E.g. for the adsorbents, this is in the coaxially arranged tube design, the conductivity in the radial direction. This thermal conductivity can be enhanced by heat conducting platelets as is proposed in
(50) In the heat transfer fluid, similar to the coaxial tube design, this is the thermal conductivity in the radial sense. When a corrugated conductive material is placed within the heat transfer fluid channel, the dominant heat transfer direction will be in a tangentially sense, i.e. substantially perpendicular to the meanders of the corrugated plate.
(51) The expression characteristic dimension used herein is to be understood as, though not to be considered limited to the relevant height, width, diameter, (equivalent) radius or thickness [m] of the adsorption material or of the fluid transfer channel taken in the direction of the dominant heat transfer. E.g. in the coaxial tube design, the characteristic dimension of the adsorption material is its (equivalent)radius, the characteristic dimension of the heat transfer channel is its width or height. In the case of a stacked plate design, wherein plates of adsorbents are sandwiched between heat transfer fluid channels, the characteristic dimension is half the height of the adsorbents material, since heat transfer occurs substantially symmetrically to both surfaces of the adsorption material layer. In that case this also applies for the heat transfer fluid channel, wherein the characteristic dimension is half the height of the heat transfer fluid channel.
(52) Yet again in the heat transfer fluid channel, in which a corrugated conductive element is applied, as is shown in
(53) The expression Specific cooling power used herein is to be understood as, though not to be considered limited to the thermal cooling power divided by the mass of the adsorption compressor [W/kg]
(54) The quantity used herein can be understood as, though is not to be considered limited to a design parameter reflecting the maximum temperature difference within the thermal wave in the direction of the dominant heat transfer over the adsorption material divided by the density of the adsorption material. The quantity is defined as presented in equation 10 herein below.
(55) The expression base side of a three way valve used herein can be understood as, though is not to be considered limited to a connection side of a three way valve, which can, by switching the valve, be connected with either a first or a second switching side of the three way valve, such that either a fluid connection is obtained between the base side and on of the two switching sides. The expression elongated used in this specification and in the claims is to be understood as, though not to be considered limited to an property of a physical entity of which one dimension, e.g. measurement or size in a first dimension is far greater than the measurement or size in the other two dimensions. In general at least one dimension departing by at least a factor 2 from the other two could for instance be recognised as being elongated.
(56) The figures represent exemplary embodiments of the invention and should not be considered limiting the invention in any way or form. Throughout the description and the figures the same or corresponding reference numbers are used for the same or corresponding elements.
(57) In
(58) In order to position the inner wall 12 precisely, the annular channel 2a can be provided with spacers. These spacers can for instance be obtained by well defined impressions in the outer tubular shell 11, forming studs that hold the inner tubular wall in position.
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(63) In
(64) In
(65) The heater or heat exchanger 32 can for instance be a gas fired heater or a heat exchanger that is fed by a normal auxiliary heat transfer fluid, originating e.g. from a solar-thermal system. In
(66) During the influx of the hot heat transfer fluid in the heat transfer channels 2A of the adsorption cell clusters 26C and 26D, due to the rather steep temperature profile, relative cold heat transfer fluid is exiting the cold sides 40C and 40D of the adsorptions cell clusters 26C and 26D. The relative cold heat transfer fluid is forced through the outlet manifold 21A, through the three way valve 29 and through the outlet conduit 38 to the cooler or heat exchanger 31.
(67) Although the heat transfer fluid originating from the adsorption cell clusters 26C and 26D is relatively cold, it needs to be further cooled in order to re-cool the adsorption cell clusters 26A and 26C.
(68) By the application of the heat transfer fluid T-connectors 16 in combination with the three way valves 27-30, only very limited amounts of heat is lost by mixing up cold and warm portions of heat transfer fluid. Each time, one arm of the T-connectors 16 and the thereto connected manifolds are switched in function, while the other arm and the thereto connected relevant manifolds are connected to a dead end conduit and thus idle. Thus in mode 1, according to
(69) When the temperature profile or front reaches the cold sides 40C and 40D, a heat detector (not shown) will provide a signal to a controller (not shown), which can turn the four three way valves 27,28,29 and 30 to switch. By switching the three way valves 27-30, the system instantaneously switches in the second mode.
(70) In the second mode, as shown in
(71) During the influx of the hot heat transfer fluid in the heat transfer channels 12A of the adsorption cell clusters 26A and 26B, due to the rather steep temperature profile, relative cold heat transfer fluid is exiting the cold sides 40A and 40B of the adsorptions cell clusters 26A and 26B. When the temperature profile or front reaches the cold sides 40A and 40B, a heat detector (not shown) can provide a signal to a controller (not shown), which can turn the four three way valves 27,28,29 and 30 to switch. By switching the three way valves 27-30, the system instantaneously switches back in the first mode, such that the cycle can start anew.
(72) The heat exchanger or cooler 31 cools down the portion of the heat transfer fluid used for cooling the adsorption beds. The hot heat transfer fluid in the inlet of the adsorption cell clusters 26c and 26d will be guided through the annular walls of the individual adsorption cells within the clusters 26c and 26d and will gradually heat up the adsorption material inside the inner walls 11 of the individual adsorption cells. Each of the arms of the T-connectors of the hot sides of the clusters are in fluid connection with a switching side of a first pair of three way valves, in such a way that the different arms of each individual T-connector is in fluid connection with the switching side of a different three way valve.
(73) By heating up the adsorption material, the adsorbed vapor will be gradually released from the adsorption material. In the length wise direction of the individual adsorption cells a front of hot heat transfer fluid will slowly expel the cold heat exchanger fluid through the annular heat transfer channels within the individual cells towards the outlet manifold 21a. This outlet manifold is connected to the heat transfer fluid three-way connection valve 29 towards the cooler/heat exchanger 31.
(74) In
(75) During heating of the clusters of adsorption cells 26A and 26B, the refrigerant gas is at relative high pressure forced out of the adsorption material and will be guided by check valve 41A and 41B towards condenser 46. In condenser 46, heat is removed from the high pressure gas such that is condenses to a liquid. After exiting the condenser, the liquefied gas is chocked over expansion valve 46, where the temperature and pressure of the gas drops considerably. At low pressure, the condensed gas will start to boil in the evaporator 49, collecting heat from its surroundings in order to re-evaporate the gas. The low pressure refrigerant gas exiting the evaporator 49 will be guided through check valves 42A and 42B to that adsorber that is in its cooling mode, collecting and adsorbing the gas.
(76) Although not shown, in order to further enhance the efficiency of the system, a counter flow heat exchanger may be integrated in the conduits 45 and 50. Thus the relative warm coolant in conduit 45 can be cooled by the relative cold refrigerant from conduit 50 before it is condensed in condenser 46.
(77) The flow diagrams of
(78) In an alternative embodiment, when the temperature profile seen along the length of the clusters 26A-D or cells 1 is relative flattened (as a result of axial dispersion), the trigger to switch flow, either switching to cooling down or switching to heating up may happen too soon for an efficient operation of the adsorber cells. Thus the Coefficient of Performance may be too low for economical service. In order to maximize the use of the heat of the heat transfer fluid, shortcuts may be integrated in both the hot and cold portions of the cycles. The clusters 26A, 26B or 26C and 26D to be cooled can be connected to the cooler 31 and the clusters 26C and 26D or 26A and 26B to be heated can be connected to the heat exchanger or heater 32. Thus substantially four modes of operation are possible. This can be performed in two ways, firstly by maintaining the flow directions in the shell sides of the clusters 26A-D or the cells 1 and secondly by switching the direction of flow when switching from cooling to heating and vice versa.
(79) In
(80) Thus cluster 26A is being heated, wherein a hot thermal wave front is moving upwards, and cluster 26C is cooled down, wherein a cold thermal wave front is moving downwards.
(81) When a relative flattened (dispersed) thermal wave breaks through, at a certain moment the cycle is switched to the first shortcut mode, which is represented by
(82) At a moment the thermal wave is fully broken through and further heating of cluster 26A as well as further cooling of cluster 26C is impossible.
(83) At that moment the cycle will be reversed, such that the cooled cluster 26C must be re-heated, the heated cluster 26A must be re-cooled. This can be performed by switching to the third mode of operation, as is represented in
(84) In this figure, the cluster 26A is now cooled down, and the cluster 26C is now heated up. Once the relative flattened (dispersed) thermal waves in cluster 26A and 26C break through, the cycle is switched to a second shortcut mode, as represented in
(85) In the
(86) Indeed it is possible also to send the thermal waves back and forth within the clusters, while still recovering losses in efficiency due to flattened (dispersed) thermal waves. In
(87) In the first mode, as represented by
(88) When the thermal heat wave tails break through, the direction of flow in both clusters 26E and 26F is reverted. In this mode, which is represented by
(89) When the tails of the heat waves break through, the system is switched back to its first operating mode.
(90) The arrangement of valves and manifolds is designed to only have a small portion of conduits, wherein hot and cold heat transfer fluid needs to pass. Thus within the embodiments of the systems according to the invention, no single valve is faced with hot and cold het transfer fluid streams. Thus efficiency losses can be minimized.
(91) The determination of the right moment to switch from the first mode to the second shortcut mode of the cycle depends on maximizing the overall efficiency or the COP of the system.
(92) It appears from validated modeling that indeed the thermal waves are rather flattened (dispersed), as is represented in
(93) The solid line in
(94) At 550 s, the temperature of the heat transfer fluid flowing out of cluster 26C becomes higher than that of the heat transfer fluid flowing out of cluster 26A. At that point, the system should switch from the first mode into the second shortcut mode, as represented in
(95) At this very moment, it is less efficient to heat up the heat transfer fluid exiting cluster 26A and to use it to further heat up cluster 26C. More efficient is to cool down this heat transfer fluid and to reuse it in the very same cluster 26A to further cool this cluster 26A.
(96) In all the operations of switching mode, as represented by
(97) From validated numerical simulations in coaxial shell and tube design, as depicted in the
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(99) Wherein ads is the thermal conductivity of the adsorbing material and r is the (equivalent) radius of the adsorbing material in an elongated tube. From this figure it can be deduced that at a high value of , the COP tends to a value of 0.4, which represents a compressor with batch heating and cooling, where no thermal wave is present. It can further be deduced that with a small (equivalent) radius a relative high COP can be reached, although the SCP may suffer.
(100) The COP and the SCP are generally desired quantities, dictated by technical specifications and commercial reasons. Once these are given and the specific adsorption material is chosen, from this plot, the (equivalent) radius of the adsorption material can be deduced.
(101) The results of this plot imply: The decrement in COP with increasing is caused by the occurrence of enlarged radial gradients at the position of the thermal wave where heat flows in or out of the adsorption material. These radial gradients are believed to reduce the steepness of the thermal wave, in effect the thermal wave becomes sort of smeared out in the elongated direction of the adsorption cell 1, causing the exit temperature to decrease earlier in a hot cell and to increase earlier in a cold cell. Enlarged radial gradients can be influenced by the three parameters: SCP, r and within the combined parameter in the following way: Proportionally by the SCP since the SCP is directly related to the power input of the cell, and logically radial gradients are directly related to the power input. Proportionally to the square of the (equivalent) radius of the adsorption material, the input power has to increase with the mass of the adsorption material within the cell in order to maintain the SCP constant, and the mass of the cell is proportional to the square of r. Proportionally to the inverted radial thermal conductivity of the adsorption material. A higher conductive heat transport lowers the thermal gradients.
(102) The COP is substantially not related to the length of the cell, as long as the cells remain elongated, wherein a length over diameter of at least 10 seems reasonable. Practically spoken, no difference in COP is obtained by either taking 20 cells of 1 m or 40 cells of 0.5 m. In both situations the SCP remains constant. However, the length of the cells does have a substantial effect on the power losses due to viscous pressure drop in the heat transfer fluid channel, as can be deduced from equation 9.
(103) Accordingly a maximum COP is achieved at a minimal SCP, which is a known trade off. More interesting is that the thermal conductivity of the adsorption material should be high, less known is that it is far more important to reduce the (equivalent) radius of adsorption material. In this equation 10 minimising the (equivalent) radius of the adsorption material appears to have the highest impact on .
(104) However a smaller (equivalent) radius of the adsorption material results in a larger number of cells. The number of cells can be calculated with:
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(106) With this (equivalent) radius, and equation 4 a maximum diameter of the heat transfer fluid channel can be determined. In addition thereto, from the equation 9, a maximum pressure drop can be deduced. The pressure drop and the Biot number can now be plotted against the thickness of the heat transfer fluid channel, as is represented in
(107) In this figure the pressure drop is scaled at the right ordinate, the Biot number is scaled at the left ordinate, the diameter of the annular heat transfer fluid channel is scaled at the abscises. Line L1 represents the calculated pressure drop, line L2 represents the calculated Biot number. From this plot, it can be deduced weather a diameter is given for which on the one end the power losses due to hydrodynamic pressure drop is not too high and on the other hand the Biot number is not too low.
(108) This plot depicts that for the combination of amorphous carbon as adsorbents, NH.sub.3 as refrigerant or adsorbing gas and water as a heat transfer fluid, in a concentric tube design, a working window is provided. This window allows the diameter of the heat transfer fluid channel to be between approximately 0.1 and 0.4 mm.
(109) In case thermal oils are used as heat transfer fluid, due to the relative low thermal conductivities, Biot requires an extremely narrow heat transfer fluid channel, leading to unacceptable pressure drop. In order to still provide a working range, radial heat conductors can be inserted within the heat transfer channel.
(110) The thermal conductivity of the heat transfer fluid can be chosen between approximately 0.1 and 10 W/mK, wherein for possible fluids, like mercury, the thermal conductivity is approximately 7-10 W/Km, and of water is approximately 0.3-1.0 W/Km. Thermal oils can have thermal conductivity of 0.1-0.6 W/Km. Accordingly workable ranges may be between 0.1 and 10 W/Km, however predominantly may lie between 0.1 and 1 W/km.
(111) For the cycle time the following equation is given:
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(113) Wherein t.sub.cycle is the total cycle time of a sorption cell or cluster i.e. the total cycle time for the ad- and desorption mode, h is the enthalpy change [J/g] of the refrigerant gas that is providing the cooling power (typically 1.2 MJ/kg for ammonia) and x.sub.net is the net amount of gas that is ad- and desorbed from the carbon in one ad- and desorption cycle, expressed in gram gas per gram adsorption material (typically 0.15 gram ammonia per gram carbon).
(114) In
(115) In
(116) Alternatively, as is depicted in
(117) In order to improve the radial conductivity of the adsorption material, e.g. radial conductors can be inserted in the adsorption material. For instance heat conductive lamellae 62A might be arranged within the adsorption material 10, in between individual adsorption units 68B, which are typically cylindrical in shape, for instance in the form of pills, as is depicted in
(118) In another embodiment, the adsorption cell or cluster thereof of the invention comprises units (68B) and conductive lamellae (62A) that are formed by a pill that is at least partly surrounded by a cup from a heat conductive material, wherein the cup contains the pill. The closely fitting cups are preferably made of the same material as the cell wall, typically stainless steel, to minimize the effects of thermal expansion mismatch between the cell and the cups. A separate thin sheet of high-conductive material (such as aluminum or graphite) can be added on one or both sides of the bottom of the cup to ensure a good heat transfer from the cell wall into the adsorption pills. This embodiment is schematically illustrated in
(119) It is also possible to provide the cup (111) entirely of the conductive material, such as aluminum.
(120) The cup may contain one or more openings (70) that serve as a channel for the refrigerant.
(121) Alternative adsorbent materials that may be applied within the scope of the invention are activated carbons, zeolites, silica gels and metal organic frameworks. The refrigerants that alternatively may be applied are carbon dioxide, hydroflorocarbons, (HFC's such as R-134a refrigerant), hydrochlorofluorocarbons (HCFC's such as R-123 refrigerant), water, methanol, ethanol, ethane, propane, isobutene, isopentane, propylene, formaldehyde and vinyl fluoride. Other suitable refrigerants may also be applied within the scope of the invention.
(122) In
(123) During manufacture of the adsorption pills 68B, the shape of the radial micro channels 69 may already be present in the adsorption pill press mould, such that no machining of the adsorption pills need to be performed afterwards. Alternatively, these micro channels 69 may be machined or etched into the adsorption material. These micro channels 69 may be applied at one or at both facing ends of the individual pills 68B.
(124) In
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(126) The first plate, the refrigerant conduit plate 75 comprises a refrigerant gas opening 73 for connecting a refrigerant manifold 78 to a refrigerant conduit 22, 25 leading to the refrigerant loop as represented e.g. in
(127) The manifold 78 and the sub manifolds 79 are closed of by a lower side of the heat transfer conduit plate 76. The top side of the heat transfer conduit plate 76 comprises a heat transfer fluid manifold 82, which can be connected via heat transfer fluid opening 74 to a heat transfer fluid T-connector 16. The manifold 82 is in fluid connection with ten heat transfer fluid sub connectors 83. These sub manifolds 83 are in fluid connection with the annular heat transfer fluid channels 2A of the individual adsorption cells 1.
(128) The manifold 82 and the sub manifolds 83 are closed by closing plate 77. The closing plate 77 comprises openings for connecting the outer cylindrical wall 11 to the closing plate 77.
(129) The plates 75, 76 and 77 can be interconnected by means of gluing, soldering of welding. The outer 11 and inner 12 cylindrical walls of the individual adsorption cells can similarly be welded, glues and/or soldered to the plates 77 and 76 respectively.
(130) In the schematic cut out view of
(131) The ends of the inner cylindrical wall 12 of the individual adsorption cells are connected with the heat transfer conduit plate 76. The ends of the inner cylindrical walls 12 are substantially flush with the upper face of the heat transfer fluid conduit plate. Thus a fluid connection can be obtained between the refrigerant sub manifolds 79 and the adsorption material 10.
(132) In
(133) The twin conduit plate 93 is at its upper side provided with a refrigerant manifold 100 and at it lower side with a heat transfer fluid manifold 106. These manifolds 100 and 106 can be machined out of the material of the twin conduits plate 93 or may alternatively be etched in the material. In the refrigerant manifold 100 considerable pressure might be present, up to approximately 20 bar. In order to contain the refrigerant inside the manifold and the system, a gasket can be placed between the twin conduits plate 93 and the closing plate 91.
(134) Although in the embodiment shown in
(135) Alternatively a second gasket may be applied in between the twin conduits manifold and the closing plate 94, in order to contain the heat transfer fluid.
(136) In
(137) The refrigerant header 100 is connected to the refrigerant conduit 86 which can be in fluid connection with the refrigerant loop as represented in
(138) Thus these clusters 26 can be integrated in the schematic flow diagrams as depicted in
(139) The cluster 26 can similarly be integrated in the process flow diagram according to
(140) The refrigerant connections of the clusters can be at one or at two sides as is explained hereinabove.
(141) The T-connectors in the heat transfer fluid conduits may be replaced by two heat transfer exits of manifolds 82, 106 at each end of the cluster.
(142) The plates 75-77, 91-95 can be glued together, welded, soldered and/or a combination thereof. The cylindrical walls can be glued, shrink fitted, welded, soldered or screwed in or onto the plates.
(143) Although the matrix of adsorption cells 1 is presented as a squared matrix, alternative arrangements are similarly possible, such as a honeycomb type of arrangement.
(144) The present invention can be applied in a large variety of fields, in particular when waste heat is available, ranging from air conditioners, such as in automotive applications, in particular trucks; to refrigerators and other applications.
EXAMPLE
(145) An experimental set-up was built to verify the performance improvements resulting from the present invention method of operation of the thermal wave, in combination with the described adsorption compressor bed suitable for thermal wave operation. The set-up consists of the following system components:
(146) Two adsorption compressor beds, each made up of two clusters of eight adsorption cells as depicted in
(147) A HTF system with heater, cooler and four three-way valves, connected as depicted in
(148) A refrigerant loop incorporating check valves, condenser, evaporator and flow restriction as depicted in
(149) A control system suitable to adjust the three-way valves, and to measure the relevant temperatures, pressures, flows and powers.
(150) With this experimental set-up the claimed method of operation of the thermal wave was clearly demonstrated, and the expected heat pump operation was verified, resulting in an improved COP in combination with a high SCP.
(151) The invention is to be understood not to be limited to the exemplary embodiments shown in the figures and described in the specification. Various modifications are considered to be variations that are part of the framework, the spirit and the scope of the invention outlined in the claims.
(152) TABLE-US-00001 Reference sign list 1 Adsorption cell 2A Annular heat transfer fluid channel 2 Heat transfer fluid connector 3 Heat transfer fluid connector 4 Vapor connector 5 Cap 6 Conduit connector 7 Skirt 8 Inner cap 9 Inner cap connecting portion 10 Adsorption material 11 Outer cylindrical wall 12 Inner cylindrical wall 13 Distribution connector 14 Connecting opening 15 Header connector 16 Heat transfer fluid T-connector 17 Vapor conduit connector 18 Vapor header manifold 19 Vapor header connector 20 Heat transfer fluid inlet header 20a-d Heat transfer fluid inlet manifolds 21a-d Heat transfer fluid outlet manifolds 21 Heat transfer fluid outlet header 22 Vapor conduit 23 Vapor conduit 24 Vapor manifold T-connector 25 Vapor manifold 26a-d Adsorption cell cluster 27 Hot heat transfer fluid three-way inlet valve 28 Hot heat transfer fluid three-way outlet valve 29 Cold heat transfer fluid three-way outlet 30 Cold heat transfer fluid three-way inlet valve 31 Cooler/Heat exchanger 32 Heater/Heat exchanger 33 Cold heat transfer fluid inlet conduit 34 Hot heat transfer fluid outlet conduit 35 Cold heat transfer fluid outlet conduit 36 Hot heat transfer fluid inlet conduit 37 Pump 38 Pump 39A-F Hot sides 40A-F Cold sides 41A-B Check valves 42A-B Check valves 43 High pressure gas conduit 44 High pressure gas conduit 45 High pressure gas manifold 46 Condenser 47 Expansion conduit 48 Expansion valve 49 Evaporator 50 Low pressure gas manifold 51 Low pressure gas conduit 52 Low pressure gas conduit 53 Three way valve 54 Three way valve 55 Three way valve 56 Three way valve 57 Three way valve 58 Three way valve 59 Manifold 60 Manifold 61 Corrugated sheet 62A Lamellae 62B Equalising conduit 63A Buffer container 63B Equalising valve 64 Heater 65 Temperature controller 66 Buffer conduit 67 Valve 68A Control valve 68B Adsorption pill 69 Radial micro channel 70 refrigerant gas channel 71 Distribution element 72 Distribution element 73 Refrigerant gas opening 74 Heat transfer fluid opening 75 Refrigerant conduit plate 76 Heat transfer conduit plate 77 Closing plate 78 Refrigerant manifold 79 Refrigerant sub manifold 80 Adsorption material retainer stub 81 Separation rib 82 Heat transfer fluid manifold 83 Heat transfer fluid sub manifold 84 Separation rib 85A Inner tube connecting opening 85B Distribution element 86 refrigerant conduit 87 Heat transfer fluid conduit 88 T-connector 89 Reinforcement rib 90 Bolt 91 Closing plate 92 Gasket 93 Twin conduits plate 94 Closing plate 95 Reinforcement ring 96 Bolt bore 97 Bolt bore 98 Rib 99 Edge 100 Refrigerant manifold 101 Spacer ring 102 Inner tube connecting opening 103 Bolt bore 104 Bolt bore 105 Outer tube connecting opening 106 Heat transfer fluid manifold L1 Line, representing Biot number L2 Line, representing pressure drop P1-P4 Pumps 107A-H Two-way valve 108A-B Four-way valve 109 Heat transfer fluid channel 110A-B Corrugated plate 111 Cup 112 Bed 1 inlet temperature 113 Bed 1 outlet temperature 114 Bed 2 inlet temperature 115 Bed 2 outlet temperature