BARTH, Ulrich (Haldenstrasse 67, 8708 Männedorf, DE)
TEUSSER, Alexander (Dreizlerstrasse 64, Stuttgart, 70619, DE)
BARTH, Ulrich (Haldenstrasse 67, 8708 Männedorf, DE)
| Claims: 1. A generator (1100) of a cooling machine which is a tube-in-tube heat exchanger housing a plurality of ascending tubes (1160) surrounded by a generator jacket tube (1105) forming a jacket cavity (1199), wherein said plurality of ascending tubes (1160) is operative to receive a refrigerant-rich solution via a solution intake (1110) of said generator jacket tube (1105); wherein said jacket cavity (1199) is operative to receive a heating medium via a heating intake (1140) of said generator jacket tube (1105), and wherein said plurality of ascending tubes (1160) is held in a fixed position within said generator jacket tube (1105) by a lower end plate (1151 ) and/or an upper end plate (1152); characterized in that said ascending tubes (1160) is constructively arranged with said heating intake (1140) and said generator jacket tube (1105) such that at least some lower portion (1161 ) of said ascending tubes (1160) remain substantially unheated. 2. The generator (1100) of a cooling machine according to claim 1 , comprising an insulating configuration that provides insulation between said heating intake (1140) and a lower portion (1161 ) of said plurality of ascending tubes (1160). 3. The generator (1100) according to claim 2 or 3, wherein said heating intake (1140) is located at a distance above said solution intake (1110) such that heating of said refrigerant-solvent solution takes place at said distance above said solution intake (1110) to minimize the quantity of bubbles in said refrigerant- solvent solution leaving said plurality of ascending tubes (1160) through their lower opening (1550). 4. The generator (1100) according to any of the preceding claims, wherein said plurality of ascending tubes (1160) extends downwardly from a lower end plate (1151 ) towards said solution intake (1110) thus forming a lower generator tube protrusion (1130), wherein said lower generator tube protrusion (1130) to minimize the probability that bubbles that are possibly generated in said solution move downward towards into lower collecting chamber (1120) of said generator (1100). 5. The generator (1100) according to any of the preceding claims comprising a blank plate (1175) between said heating intake (1140) and said solution intake (1110) covering the cross-sectional area of the jacket cavity (1199) formed by said generator jacket tube (1105) to divide said jacket cavity (1199) into an upper cavity (1122) and a lower cavity (1121 ), and wherein said blank plate (1175) has an insulating effect which minimizes the amount of energy transferred to said lower portion (1161 ) of said at least one ascending tubes (1160). 6. The generator (1100) of claim 4 or 5, wherein said plurality ascending tubes (1160) are coupled in a gastight and pressure tight manner with said lower end plate (1151 ), wherein said lower end plate (1151 ) covers a cross-sectional area of said jacket cavity (1199), said lower end plate (1151 ) thus preventing escape of said bubbles out of the bottom of said plurality ascending tubes (1160) into said jacket cavity (1199). 7. The generator (1100) of claim 4 or 5, wherein said blank plate (1175) is located closer to said heating intake (1140) than to said solution intake (1110). 8. The generator (1100) according to any of the preceding claims comprising deflection panels (1170) which protrude in a horizontally staggering and vertically spaced manner with respect to one another upward starting from said heating intake (1140) into said generator jacket cavity (1199), wherein said deflection panels (1170) have a vertical distance between one another and which cover partially said cross-sectional area. 9. The generator (1100) according to any of the preceding claims, comprising a plurality of upper generator tube protrusions (1165) extending beyond an upper end plate (1152), which is located between said heating intake (1140) and a solvent outlet (1190) being above said upper end plate (1152). 10. The generator (1100) according to claim 9, wherein the upper surface of said upper end plate (1152) together with said generator jacket tube (1105) constitute a solvent reservoir or upper collecting chamber operative to receive solvent leaving said plurality of ascending tubes (1160), and wherein said upper generator tube protrusions (1165) prevent backflow of said solvent leaving a first ascending tube into a second ascending tube. 11. The generator (1100) according to claim 9 or 10, wherein said upper end plate (1152) comprises a collecting plate (1153) to which said plurality of upper generator tube protrusions (1165) are mechanically coupled. 12. The generator (1100) according preceding claims, wherein a pipe (1197) communicates with a refrigerant (vapor) outlet (1180) of said generator (1100), wherein said pipe (1197) is shaped such to prevent backflow of condensed refrigerant vapor back into said generator (1100). 13. The generator (1100) according to claim 12, wherein said pipe (1197) extends downwardly from said refrigerant outlet (1180). 14. The generator (1100) according to claim 13, wherein said pipe (1197) has a projection in height (1194) leading to another connection (1600), wherein said projection is implemented by incorporating a kink (1198) in pipe (1197). |
FIELD OF THE INVENTION
[0001] The present invention relates to the field of cooling machines and more particularly to the field of Diffusion-Absorption Cooling Machines.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a refrigerating unit, which can be operated by means of a thermal solar system as energy source, according to the preamble of claim 1. [0003] In the prior art, the general concept of a refrigeration-unit that is based on the concept of a diffusion-absorption mechanism, has been disclosed in US patent 7201017 to Barth et al, which teaches a refrigerating unit having an expeller, a triple heat exchanger, a condenser, an evaporator, a gas heat exchanger, an absorber, and a fuel reservoir which are actively connected to form a closed fuel circuit with one another. Such a diffusion-absorption refrigerating unit is suitable to be operated by means of various energy sources. Among these, a thermal solar system as well as another heat transfer medium circuit, e.g. from a heat recovery process, can be used for the alternative or enhancing energizing of the refrigerating unit. A diffusion-absorption refrigerating unit is thus advantageously suitable, in a manner which is flexible and favorable for operation, to be energized with thermal energy by means of a thermal solar system as well as, if needed or desired, by additional or alternative energy sources.
[0004] Generally, the refrigerating unit is characterized by comprising solely non-moving parts (i.e., for example, no pumps and/or compressors). As a consequence, the refrigeration unit is maintenance-friendly, relatively favorable from the standpoint of cost and can be operated, at least nearly without noise. Furthermore, it is possible to develop the refrigerating unit so that the mounting of several refrigerating units in parallel can be realized in a relatively simple manner.
[0005] The unit can be actively connected to an expeller formed as a gas bubble pump for the desorption and vaporization of a fuel contained in a solution. A gas bubble pump is particularly suitable for desorbing and vaporizing, in a manner which is effective and favorable for operation, a fuel contained in a solution such as, for example, ammonia (NH3) in an ammonia-rich solution. Furthermore, a gas bubble pump permits an efficient heat transfer accomplished by means of a thermal energy source, which is a prerequisite for reliable and effective desorption and vaporization of the fuel (ammonia). [0006] Nevertheless, the performance of the generator of the unit disclosed in US patent 7201017 has to be further improved in terms of efficiency. It is thus an object of the invention to provide a refrigeration unit having improved performance over the refrigeration unit disclosed in the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The invention will be further understood and appreciated from the following detailed description taken in conjunction with the drawings in which: [0008] Figure 1 is a schematic cross-sectional side view illustration of a lower part of a generator, according to an embodiment of the invention;
[0009] Figure 2 is a schematic cross-sectional side-view illustration a lower part of a generator, according to an alternative embodiment of the invention; [0010] Figure 3 is a schematic cross-sectional side-view illustration of an upper part of a generator, according to an embodiment of the invention;
[0011] Figure 4 is a schematic cross-sectional side-view illustration of an upper part of a generator, according to an alternative embodiment of the invention; [0012] Figure 5 is a schematic cross-sectional side-view illustration of an upper part of a generator, according to a yet alternative embodiment of the invention; [0013] Figure 6 is a schematic cross-sectional side-view illustration of an pipe communicating with a refrigerant (vapor) outlet of an upper part of a generator according to an embodiment of the invention;
[0014] Figure 7 is a schematic cross-sectional side view illustration of a unitary component assembly evaporator - gas heat exchanger - absorber, according to an embodiment of the invention;
[0015] Figure 8 is a schematic cross-sectional side view illustration of an impelling unit, according to an embodiment of the invention; and
[0016] Figure 9 is a schematic cross-sectional side view illustration of a pre-cooling configuration before the evaporator. DESCRIPTION OF THE INVENTION
[0017] It should be noted that a reference to "a" or "an" element should not necessarily be interpreted as being only one of that element. Accordingly, a reference to "a bypass tube" for example may also be interpreted as "at least one bypass tube". Summary of the embodiments of the invention
[0018] The present invention discloses a generator of a cooling machine which is a tube-in-tube heat exchanger housing a plurality of ascending tubes surrounded by a generator jacket tube forming a jacket cavity. The plurality of ascending tubes is operative to receive a refrigerant-solvent solution via a solution intake of the generator jacket tube. The jacket cavity is operative to receive a heating medium via a heating intake of the generator jacket tube, and the plurality of ascending tubes is held in a fixed position within the generator jacket tube by a lower end plate and/or an upper end plate. [0019] In embodiments of the invention, the ascending tubes are constructively arranged with the heating intake and the generator jacket tube such that at least some lower portion the ascending tubes remain substantially unheated by the heating medium provided from the heating intake.
[0020] In embodiments of the invention the generator has an insulating configuration that provides insulation between the heating intake and a lower portion of the plurality of ascending tubes.
[0021] In embodiments of the invention, the heating intake is located at a distance above the solution intake such that heating of the refrigerant-solvent solution takes place at a distance above the solution intake to minimize the quantity of bubbles in the refrigerant-solvent solution leaving the plurality of ascending tubes through their lower opening.
[0022] In embodiments of the invention, the plurality of ascending tubes extends downwardly from the lower end plate towards the solution intake thus forming a lower generator tube protrusion minimizing the probability that bubbles that are possibly generated in the refrigerant-solvent solution move downward towards into collecting chamber of the generator.
[0023] In embodiments of the invention, the generator includes a blank plate located between the heating intake and said solution intake and mechanically coupled with the ascending tubes, e.g., by point welding. The blank plate covers the cross-sectional area of the jacket cavity formed by the generator jacket tube to divide the jacket cavity into an upper cavity and a lower cavity. The blank plate has an insulating effect which minimizes the amount of energy transferred to the lower portion of the ascending tubes. [0024] In embodiments of the invention, the plurality of ascending tubes is coupled in a gastight and pressure tight manner with the lower end plate. The lower end plate covers a cross-sectional area of said jacket cavity and thus prevents escape of bubbles out of the bottom of the plurality ascending tubes into the jacket cavity. [0025] In embodiments of the invention, the blank plate is located closer to the heating intake than to the solution intake.
[0026] In embodiments of the invention, the generator includes deflection panels which protrude in a horizontally staggering and vertically spaced manner with respect to one another upwardly starting from the heating intake into the generator jacket tube, wherein the deflection panels have a vertical distance between one another and which cover partially the cross-sectional area.
[0027] In embodiments of the invention, the generator includes a plurality of upper generator tube protrusions extending beyond an upper end plate, which is located between the heating intake and a solvent outlet being above the upper end plate. [0028] In embodiments of the invention, the upper surface of the upper end plate together with the generator jacket tube the constitute a solvent reservoir or collecting chamber operative to receive solvent leaving the plurality of ascending tubes from the top, and wherein the upper generator tube protrusions prevent backflow of the solvent leaving a first ascending pipe into a second ascending pipe.
[0029] In embodiments of the invention, the upper end plate includes a collecting plate to which the plurality of upper generator tube protrusions is mechanically coupled. [0030] In embodiments of the invention, a pipe is communicating with a refrigerant outlet of the generator, wherein the pipe is shaped such to prevent backflow of condensed refrigerant vapor into the generator.
[0031] In embodiments of the invention, the pipe extends downwardly from said refrigerant outlet.
[0032] In embodiments of the invention, the pipe has a projection in height leading to another connection, wherein the projection is implemented by incorporating a kink at the outlet of the pipe.
[0033] Detailed description of the invention
[0034] Reference is now made to Figure 1. According to an embodiment of the invention, a generator 1100 is configured similarly to a shell and tube heat exchanger comprising a plurality of perpendicularly upright interior ascending tubes 1160 which are surrounded by a generator jacket tube 1105. A heating medium (not shown) required for heating a solvent (not shown) flows in a jacket cavity 1199 (provided, e.g., over a heating intake 1140), whereas refrigerant-solvent solution flows in ascending tubes 1160. In ascending tubes 1160, the refrigerant is separated from the solvent as a result of the heating. The refrigerant which has been transferred to the gaseous phase rises upwards in ascending tubes 1160 and at the same time conveys the refrigerant-solvent solution upwards.
[0035] In an embodiment of the invention, ascending tubes 1160 are constructively arranged with heating intake 1140 and generator jacket tube 1105 such that at least a lower portion 1161 of said ascending tubes 1160 remain substantially unheated. [0036] Otherwise stated, generator 1100 has an insulating configuration that provides insulation between heating intake 1140 and a lower portion 1161 of the plurality of ascending tubes 1160. For example, in order to prevent escape of the refrigerant vapor at the lower commencement of ascending tubes 1160, heating by the external medium may not be performed at the lower commencement of ascending tubes 1160 but only from a certain height H thereabove, in order to minimize the quantity of bubbles in said refrigerant-solvent solution at a location in ascending tubes 1160 which may be at least approximately in alignment with solution intake 1110. This may be constructively implemented, for example, by mechanically coupling a lower generator tube protrusion 1130 to ascending tubes 1160 which projects into lower collecting chamber 1120 of generator 1100.
[0037] Additional reference is now made to Figure 2. In some embodiments, a blank panel 1175 may be employed covering the entire free inner cross-sectional area of generator jacket cavity 1199. The position of blank panel 1175 is below the heating intake 1140 (or heating outlet 1140 depending on the direction of flow of the heating medium through generator jacket cavity 1199). With lower generator end plate 1151, blank panel 1175 forms a dead space 1650 of a specified size through which no flow of heating medium takes place.
[0038] According to some embodiments of the invention, blank plate 1175 is located closer to heating intake 1140 than to solution intake 1110.
[0039] In some embodiments of the invention, ascending tubes 1160 depart from lower end plate 1151 such that lower end plate 1151 covers said cross-sectional area, thus preventing escape of bubbles, which are nevertheless generated, out of the bottom of ascending tubes 1160 into a jacket cavity 1199 formed by jacket tube 1105 and ascending tubes 1160. [0040] According to some embodiments of the invention, generator 1100 includes deflection panels 1170 which protrude in a horizontally staggering and vertically spaced manner with respect to one another upward starting from heating intake 1140 into generator jacket tube 1105. Deflection panels 1170 may have a vertical distance between one another and partially cover the cross-sectional area of jacket cavity 1199 i.e., they partially protrude in a horizontal manner into generator jacket tube 1105. Deflection panels 1170 do not protrude into the cavity of ascending tubes 1160. [0041] Additional reference is now made to Figure 3, 4 and 5. According to some embodiments of the invention, generator 1100 features at the upper end of ascending tubes 1160, upper generator tube protrusions 1165 of a specific height H may be provided at the piping beyond upper generator end plate 1152. Upper generator tube protrusion 1165 may prevent any backflow of the conveyed refrigerant-solvent solution into ascending tubes 1160.
[0042] At the upper end of ascending tubes 1160, the gaseous refrigerant is separated from the liquid refrigerant-solvent solution. The refrigerant-solvent solution is collected by a collecting plate 1153 in order to then leave generator 1100 in the direction of a solution heat exchanger through a solvent outlet 1190. The gaseous refrigerant flows into refrigerant outlet 1180.
[0043] It should be noted that in the embodiment wherein generator 1100 comprises a plurality of ascending tubes 1160, it may happen that only some of ascending tubes 1160 convey refrigerant-solvent solution at a given time. It is therefore possible that refrigerant-solvent solution which has already been conveyed upwards in the non- conveying ascending tubes 1160 may flow back into the non-conveying ascending tubes 1160. To prevent such a blackflow, generator 1100 may include collecting plate 1153 which may be fastened on upper generator end plate 1152 adjacent to upper generator tube protrusion 1165. Collecting plate 1153 includes holes at the points at which ascending tubes 1160 are coupled with upper generator end plate 1152. At these holes, upper generator tube protrusions 1165 may be fixedly coupled with collecting plate 1153. Upper generator tube protrusions 1165 with collecting plate 1153 may thus form a collecting chamber in which the conveyed solution can be collected to prevent backflow of the solution into ascending tubes 1160.
[0044] Further reference is now made to FIGURE 6. In order to prevent condensed refrigerant vapor from being able to flow into an upper collecting chamber 1195 of generator 1100, a pipe 1197 coupled with a refrigerant outlet 1180 may have a kink 1198, which passes the refrigerant vapor downwards only over a specified section. Only then is the connection made to a dephlegmator or to the gas inlet of the condenser via connection 1600.
[0045] Component assembly: evaporator - gas heat exchanger - absorber [0046] Reference is now made to Figure 7. In some embodiments, a gas heat exchanger 610 and an absorber 620 are connected constructively to form a unitary or single integrated functional unit 600, thereby possibly increasing the compactness of the cooling machine.
[0047] A collecting chamber 615 for the refrigerant-rich auxiliary gas may have to be provided between absorber 620 and gas heat exchanger 610 for connection of absorber 620 with gas heat exchanger 610. From collecting chamber 615 at least one bypass tube 640 passes by its absorber head 622 into the lower region of absorber 620. The refrigerant-rich auxiliary gas is distributed there to individual absorber tubes 625. At least one transfer tube 630 passes through collecting chamber 615 which passes the low-refrigerant auxiliary gas from absorber head 622 into gas heat exchanger 610. Lower end plate 616 of collecting chamber 615 is provided with openings (not shown) through which unvapohsed refrigerant can pass into absorber 620. Gas heat exchanger tubes 650 are guided seamlessly as far as lower gas heat exchanger end plate 611 to connect evaporator 1000 with gas heat exchanger 610. Accordingly, the continuation of gas heat exchanger tubes 650 are evaporator tubes 1115. The lower evaporator end plate 612 thus constitutes then at the same time upper gas heat exchanger end plate 612. Evaporator tubes 1115 are connected in a gastight manner and in a pressure-tight manner to the required extent to the upper evaporator end plate (not shown) and to lower evaporator end plate 612 and lower gas heat exchanger end plate 611 by suitable means such as, for example, welding, soldering, bonding or rolling. In an alternative embodiment of the invention, instead of connecting evaporator 1000 with gas heat exchanger 610, another collecting chamber (not shown) for the refrigerant-rich auxiliary gas may be created between evaporator 1000 and gas heat exchanger 610. Bypass tube 1140 of evaporator 1000 for the low- refrigerant auxiliary gas may be passed through this other collecting chamber. Evaporator tubes 1115 are connected in a gastight manner and in a pressure-tight manner to the required extent to the upper and lower evaporator end plate 612 by suitable means such as, for example, welding, soldering, bonding or rolling. As a consequence, gas exchanger tubes 610 are connected in a gastight manner but no longer necessarily in a pressure-tight manner to the upper and lower gas heat exchanger end plate by suitable measures.) [0048] Impelling unit
[0049] Reference is now made to Figure 8. An impelling unit 700 of a cooling system is in an embodiment of the invention a tube-in-tube heat exchanger having at least one perpendicularly upright interior ascending pipe 720, which is surrounded by the impelling unit's jacket wall 710. The refrigerant-rich solution coming from the solution heat exchanger or absorber flows via opening 702 from bottom to top in ascending pipe(s) 720 exits via opening 703 to generator 1100. In jacket space 740, the refrigerant-low solution received from generator 1100 via opening 701 flows from top to bottom in counterflow via opening 704 to the solution heat exchanger or absorber. As a result of the higher temperature of the refrigerant-low solution compared to the refrigerant-rich solution, the refrigerant-low solution transfers heat to the refrigerant-rich solution. Refrigerant (e.g., Ammonia) is thereby converted into the gaseous phase collected in vapor dome 730 and flows via gas opening 705 to the dephlegmator (not shown) or condenser (not shown).
[0050] The rich-refrigerant solution flows away in the direction of generator 1000. It is important that the outflow takes place at a lower level than the liquid level of refrigerant- rich solution in the reservoir of absorber 620.
[0051] It should be noted that heating of the rich solution is occurs by the hot poor solution. Accordingly, the main function of the impelling unit is the one of a solution heat exchanger, i.e., in the case of the embodiment of the invention, facilitating heat transfer from the rich solution to the poor solution. [0052] Pre-cooling of the refrigerant before the evaporator
[0053] Reference is now made to Figure 9. A connecting tube may be communicatively coupled between a condenser 950 and an evaporator head 900 which is dimensioned so that in addition to the refrigerant 930 liquefied in the condenser, a gas phase 940 can also coexist. This serves to provide the necessary pressure compensation between condenser 950 and evaporator head 900. As a result of circulation of the auxiliary gas in this gas phase 940, a pre-cooling of a refrigerant 930 takes place due to partial evaporation of refrigerant 930. The pre-cooling can be further increased by communicatively coupling a separate gas line 910 parallel to and above connecting tube 920. Gas line 910 is coupled with evaporator head 900 and the transition between condenser 950 and evaporator head 900. Alternatively, gas line 910 can also run inside connecting tube 920. Suitable measures should be taken to prevent any penetration of liquid refrigerant 930 into gas line 910. [0054] It should be noted that the present invention may be employed in association with various energy sources, including but not limited to, any type of passive energy sources such as, for example, e.g., solar energy, process heat, and the like. In some embodiments, the cooling machine may be employed as a heating pump. [0055] While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the embodiments. Those skilled in the art will envision other possible variations, modifications, and programs that are also within the scope of the invention.