WO1993018354A1

WO1993018354A1 - Externally heated, regenerative heating and refrigerating machine

Info

Publication number: WO1993018354A1
Application number: PCT/DE1993/000192
Authority: WO
Inventors: Peter Hofbauer
Original assignee: Viessmann Werke Gmbh & Co.
Priority date: 1992-03-05
Filing date: 1993-03-05
Publication date: 1993-09-16
Also published as: DE4206957A1; EP0585430A1; EP0585430B1; ATE155228T1; DE59306864D1

Abstract

An externally heated, regenerative heating and refrigerating machine working according to the Vuilleumier cyclic process has a pressure-tight housing (1) with two linearly and coaxially movable pistons (2, 3) arranged therein that delimit together a warm working volume (5). One of the pistons (2) delimits in the housing (1) a hot working volume (7) externally supplied with heat (6) by means of a burner (22) and the other piston (3) delimits a cold working volume (7). All three variable working volumes (5, 6, 7) communicate with each other through intermediate regenerators and heat exchangers. A control gear (S) for the pistons (2, 3) is arranged in the housing (1). The housing (1) is designed as a tubular pressure vessel (1') with forward and return flow connecting branches (10 to 13) for two heat transfer circuits. All regenerators (8, 9) and heat exchangers (14, 15) are arranged within the pressure vessel (1'). A piston bushing (16) with overflow openings (17, 18, 19) that lead to the working volumes (5, 6, 7) is also arranged in the pressure vessel (1'). The heat exchanger (15) for one of the heat transfer media delimits the cold working volume (7) on the one side and on the other side it delimits a space (70) in which is arranged the control gear (S) that cooperates with the piston (2, 3).

Description

Externally heated, regenerative heating and cooling machine

The invention relates to an externally heated, regenerative, heating and cooling machine operating according to the Vuilleumier cycle process according to the preamble of patent claim 1.

Such heating and cooling machines have already been developed based on the Vuilleumier cycle, which has been known since 1918, and have among other things. the advantage that these can be operated with helium or hydrogen gas instead of environmentally harmful CFCs.

Regarding the Vuilleumier cycle process and its constructive implementation possibilities, reference is made to DE-Z: gwf-gas / erd-gas 127 (1986) No. 5, pages 205-210.

However, the "control gear" mentioned in the preamble of claim 1 is not a gear which can be used to control the piston movements, but only springs between the piston and the housing, which together with the piston engage in the housing form an oscillatory system. This does not apply directly to a constructive embodiment of such a "Vuilleumier machine" (see also the above-mentioned literature reference), in which the cylinders for the pistons are offset by 90 ° and the pistons are positively coupled to one another by a crank mechanism which just as the basic principle corresponding to the preamble with linear and coaxially movable pistons is considered disadvantageous in that all regenerators and heat exchangers are peripherally assigned to the actual machine, which requires correspondingly complex connection, sealing and also insulation measures.

The invention is accordingly based on the object of improving a machine of the generic type in such a way that in practice such a machine, including the necessary heat exchangers and regenerators, in a compact construction for the implementation of the advantageous Vuilleumier cycle process.

REPLACEMENT LEAF can be created wisely, which is nevertheless easy and simple to assemble and should be able to intervene in the movement process of the pistons with respect to a power control.

This object is achieved with a machine of the type mentioned at the outset according to the invention by the features stated in the characterizing part of patent claim 1. Advantageous further developments result from the subclaims.

This design according to the invention not only has the advantage that all the elements required for carrying out the cyclic process are combined in a single tubular container in a very small space, but these elements can also all be produced from an open side during manufacture or assembly insert it, which is then only suitable for sealing in a pressure-tight manner. In this tubular container, at the same time, another space for accommodating a control gear is accommodated, namely below the "cold side" of the machine, which has the advantage that all movable elements can be exchanged in the event of damage to be able to carry out from this side of the tubular container. As a consequence of this design according to the invention, the entire system carrying the operating gas is enclosed in the pressure vessel without any external conduits, which only has to be provided with connections for the two heat transfer medium circuits.

Advantageous configurations of such a machine consist in the following:

The two pistons are provided with piston rods which jointly engage in the space additionally arranged on the cold side, in which currentable and elastic control elements for the piston movements are arranged, the piston rods with their piston rod ends spacing between two corresponding to the maximum piston stroke E-magnets engage and each piston rod end between two against the Compressed springs supported on the walls of the room are clamped, and the piston rod of the piston which limits the hot working volume extends through the piston rod of the other piston, which is designed as a tube, and the ends of the piston rod are provided with two-arm cross arms, each of which is located between E-magnets and compression springs. In addition to the fact that, due to this design, the movement of the pistons can be controlled in an elegant manner for the purpose of regulating the power of the machine, the compact design is also consistently adhered to and both piston rods are oriented towards the cold side of the machine, on which the common control gear is also located.

The heat exchanger delimiting the accommodation space for the control gear is concavely curved towards the piston, as seen from the outside, and the associated piston on the side of the cold working volume is curved accordingly. The heat exchanger, which is designed to be pressure-favorable due to the curvature, forms, as it were, a bell that bulges over the additional space, the shape of which also simultaneously forms a relatively large heat transfer area, which is favorable because there are no large temperature openings in this "cold" area. Likewise in the interest of the largest possible heat transfer area and a pressure-stable design of the end face of the pressure vessel on the hot side, the end wall, viewed from the outside, is also concave and the piston is designed to match the shape of the end wall accordingly. Since this end wall is subjected to high temperatures from the burner, this end wall on the burner side is advantageously provided with an annular cooling channel on its peripheral edge, which has corresponding coolant supply and return connections.

Apart from the fact that the "hot" regenerator can also be arranged elsewhere in the pressure vessel on its hot side, an embodiment is preferred in such a way that the "hot" regenerator is integrated in the piston which essentially limits the hot working volume on the piston side. As a result, when the piston is in the highest position, the regenerator comes into direct contact with the end wall and longer feed paths of the hot operating gas to the regenerator are eliminated.

Also in the sense of short flow paths and a compact design, it is provided that the heat exchanger connectable to a heating circuit be arranged on both sides of the overflow opening between the piston liner and the pressure vessel wall and this heat exchanger on the cold side also has the "cold" regenerator in the space between the piston liner and upstream of the pressure vessel wall. The rest of the intermediate space is filled with shape-adapted and easily insertable heat insulation material, keeping the inflow spaces assigned to the overflow openings free.

The regenerative heating and cooling machine according to the invention, including further advantageous refinements, will be explained in more detail below with the aid of exemplary embodiments.

It shows schematically

1 shows a longitudinal section through the heat and cold machine _?

Fig. 2, 3 structural details regarding the controls;

4 shows an air preheater to be assigned to the machine or the burner,

5 shows an enlarged section through a special embodiment of the warm working volume;

E -S _Ä ΓZBLÄΠΓ Fig. 6 shows a section through a further and preferred embodiment of the machine and

7A-M the movement diagrams of the pistons, in each case in connection with the p-v diagram.

With reference to FIG. 1, the machine consists in a known manner of a pressure-tight housing 1 with two pistons 2, 3 which are linearly and coaxially movable therein, which together limit a warm working volume 5, and of which one piston 2 in the housing 1 is a hot externally by means of a burner 22 which is subjected to heat (6) and the other piston 3 limits a cold working volume 7, the three variable working volumes 5, 6, 7 being connected to one another with the interposition of regenerators and heat exchangers, and where a control gear S for the pistons 2, 3 is arranged in the housing 1. For such a machine is now to achieve the object, essential that the housing 1 as rohrför- miger pressure vessel l is ¹ formed with supply and return ports 10 to 13 for two heat carrier circuits, and in the pressure vessel 1, all the regenerators 8, 9 and Wärme¬ Exchangers 14, 15 are arranged that further a piston liner 16 with overflow openings 17, 18, 19 leading to the working volumes 5, 6, 7 is arranged in the pressure vessel 1 ', and that in the pressure vessel 1' the heat exchanger 15 for the one heat transfer medium on the one hand cold working volume 7 and on the other hand delimits a space 70 in which the control gear S which is operatively connected to the pistons 2, 3 is arranged. In the piston positions shown, the hot and cold working volumes 6, 7 cannot be seen in FIG. 1, but they can be seen in FIGS. 7A-J, in which the individual movement processes of the two pistons 2, 3 are shown, each with an adjacent pv diagram , in which the pressure orientations in the working volumes are indicated with corresponding arrows. For reasons of clarity, the regenerators 8, 9 and the heat exchangers 14, 15 including the heat exchanger, to which heat is supplied from the outside, in contrast to the exemplary embodiment in FIG.

EHAATZBLAF lie and illustrated only schematically in Fig. 7 machine.

The flows of both the operating medium gas and the heat transfer media in the heating and cooling circuits to be connected, which are not shown, do not require any further explanation, since nothing else arises in this regard than in the known Vuilleumier process.

In the illustrated and preferred embodiment, the "hot" regenerator 8 is integrated in the manner shown in the piston 2, which limits the hot working volume 6. Behind or below the regenerator 8, a channel 8 ′ ensures that the hot operating gas flows out to the overflow openings 17 to the heat exchanger 14 and into the warm working volume 5.

For the reasons mentioned, the end wall 23 facing the burner 22 is concave, as seen from the outside, and the piston 2 with its integrated regenerator 8 is adapted to this shape of the end wall 23 accordingly.

Since the connecting wall 23 assumes a high temperature, it is, as shown, provided with an annular cooling channel 24, the supply and return connections 24 'of which are integrated in a suitable manner in a heating circuit, but which are also connected to a separate circuit can.

The heat exchanger 15 delimiting the space 70 on the cold side KS is also concave towards the piston 3, seen from the outside, and likewise the piston 3 on the side of the cold working volume 7. The curvature of the heat exchanger 15 is at least in the peripheral edge regions are kept somewhat smaller than that of the surface of the piston 2 facing it, so that the operating gas is quasi squeezed out

REPLACEMENT LEAF discharged to the cold working volume 7 and fed to the regenerator 9.

With reference to FIG. 5, a partition wall 32 provided with through-flow openings, which also divides the inflow space 26 to the heat exchanger 14, can advantageously, but not necessarily, be arranged centrally and stationary in the warm working volume 5 between the pistons 2, 3, and in whose flow-through openings additional regenerators 33 are arranged. A prerequisite for this is that the heat exchanger 14 which can be connected to a heating circuit is arranged on both sides of the overflow opening 18 between the piston liner 16 and the pressure vessel wall 1 "and this heat exchanger 14 on the cold side KS of the" cold "regenerator 9 also in the intermediate space 25 of the piston run - Bush 16 and the pressure vessel wall 1 "is connected upstream.

The remaining free spaces in the intermediate space 25 are filled with heat insulation material 27 while keeping the inflow spaces 26 assigned to the overflow openings 17, 18, 19 free, which, correspondingly preformed and dimensionally stable, like all other elements when the machine is assembled, is simply placed in the pressure vessel 1 'is inserted.

Without affecting the compact design of the machine, the two pistons 2, 3 are provided with piston rods 20, 21, which together engage in the space 70 in which currentable and elastic control elements for the piston movements are arranged. As can be seen from FIG. 1, the piston rods 20, 21 engage with their piston rod ends 20 ', 21' between two E-magnets 28, 29 which are spaced apart according to the maximum piston stroke H. Each piston rod end 20 ', 21' is arranged clamped between two compression springs 30, 31 supported against the walls of the space 70, the piston rod 20 of the piston 2 delimiting the hot working volume 6 being the piston designed as a tube engages rod rod 21 of the other piston 3, and the piston rod ends 20 ', 21' are provided with two-arm cross arms 20 ", 21", ie, only these cross arms 20 ", 21" engage in each case between the E magnets 28, 29 and the compression springs 30, 31 in the exemplary embodiment.

With correspondingly program-controlled energization of the E-magnets 28, 29, it is possible in this way to intervene in the movement process of the two pistons 2, 3, and the unavoidable friction losses in the machine can also be compensated for at the same time. In order to keep the control energy to be supplied as low as possible, the necessary and controllable e-magnets 28, 29 are advantageously combined with permanent magnets (not shown), so that the controlled energization of the e-magnets 28, 29 only affects the piston positions or Movement phases limited in which the pistons 2, 3 are held. With this design, the machine can be operated as follows, assuming a central position (warm volume 5 = 0) (see FIGS. 7A-J):

Both pistons 2, 3 go up. If the highest position is reached, the upper piston 2 is held in place and the lower piston 3 goes down. When this has reached its lowest position, in which it is held, the upper piston 2 is released and moves to the lower piston 3, after which both pistons 2, 3 go up together again, etc. As can be easily imagined, one can click on them Intervene in a way that regulates the piston movements and thus regulate the output, because without having to change the external heat input through the burner 22, the holding period of the pistons 2, 3 can be changed by appropriately controlled energization of the e-magnets 28, 29.

In order to create favorable pressure ratios in the warm volume 5 between the two pistons 2, 3 in relation to the dimensioning of the piston area delimiting the hot volume, ie to increase the "residual Stirling effect", training is provided for this purpose (see FIGS. 1 and 5) that the piston 2 delimiting the hot working volume 6 is provided with a central piston extension 40 on its piston surface 2 'delimiting the warm working volume 5, which plunges into a Form-fitting recess 41 of the other piston 3 engages, the piston rod 20 being arranged on the bottom 42 of the piston extension 40 and the piston rod 21 being arranged on the bottom 43 of the recess 41. The in Fi. 1, 5 indicated seals

45 are not absolutely necessary, since the space 44 is also housed in the closed housing 1 and there is nothing to the extent that the equipment (for example helium) is also located in this space 44 or can get into it. The space 44 in the recess 41, which also changes during the piston movements, is expediently connected to the gas-carrying spaces via a bypass line (not shown).

The burner 22, the piston liner 16 and the pressure vessel 1 'and the latter, in particular in connection with the heat exchanger 15 or the space 70, should now be mentioned briefly.

In adaptation to the concavely curved end surface 23, the gas burner 22 is designed in the form of a mushroom-head burner, to which a heat exchanger 28 provided with spiral chambers (see FIG. 4) is assigned, on the one hand the hot exhaust gases flow through and on the other hand a cooling medium (heating water) and the fuel-air mixture for the burner, as is illustrated in FIG. 4 by corresponding arrows.

As far as the pressure vessel 1 'is concerned, the base carrying the heat exchanger 15 is in the illustrated embodiment

46 welded into the pressure vessel 1 '. However, it is also possible, as is readily conceivable, to flange-mount this base 46 in a pressure-tight manner, which has the advantage that the two pistons 2, 3 can be pulled out together with the control elements and can be replaced if necessary. The same applies to the piston liner 16, which is preferably made of ceramic, between whose lower edge 16 'and the bottom 46 a spring ring 47 is arranged.

REPLACEMENT LEAF The embodiment shown in FIG. 6, which is preferred and which has an even more favorable and simple structure, works on the same principle as explained for FIG. 7. The corresponding reference signs are used for this embodiment and for the essential parts.

This embodiment is characterized in that the piston running surface 16 according to FIG. 1 here is designed as a heat exchange wall 16 'between the heat transfer media and the gas side and with this wall 16' in the region of the piston 3 on the cold side on the gas side includes the regenerator 9 and the other separates the spaces 50, 50 'carrying heat transfer media from one another. The wall 16 'in the exemplary embodiment is provided with helical gears 51 which are pronounced with respect to the pressure vessel wall 1 ".

The entire relatively complex arrangement of the heat exchanger 15 according to FIG. 1 below the piston 3 is omitted here, since this now comprises the lower half of the piston 3 working on the cold side KS. Only the heat insulation 27 is to be arranged downward toward the space 70 shown in cross section in FIG. 6. The working volumes for the gas side are here also designated 6, 7, between which and the working space 5 the gas flows or is pumped back and forth along the gaps between the pistons 2, 3 and the heat exchange wall 16 'in accordance with the piston movements .

In the exemplary embodiment shown in FIG. 6, the regenerator 8 is also integrated in the piston 2. However, it is also possible to arrange the regenerator 8 stationary there instead of the upper heat insulation 27.

Instead of using control elements for the piston control, as explained for FIGS. 1-3, the rest (in FIG. 1 on the right side) for the “cold” piston 3 should have a so-called negative spring characteristic also, as indicated in FIG. 6 below, mechanical space 70 Control elements in the form of a cam drive, for example, which also applies to the embodiment according to FIG. 1 of the machine.

Claims

Claims:

1. Externally heated, regenerative heating and cooling machine working according to the Vuilleumier cycle process, consisting of a pressure-tight housing (1) with two pistons (2, 3) which are linearly and coaxially movable therein and which together produce a warm working volume ( 5), and one of the pistons (2) in the housing (1) is a hot one (6) and a piston (3) is used to heat it from the outside, and the other piston (3) is a cold working volume ( 7), the three variable working volumes (5, 6, 7) being interconnected with the interposition of regenerators and heat exchangers, and a control gear (S) for the pistons (2, 3) is arranged, characterized in that the housing (1) as a tubular pressure vessel (1 '), accessible only from the piston transmission side and closable there in a pressure-tight manner, with flow and return connections (10 to 13) for two heat transfer circuits a is formed and in the pressure vessel (1 ') all the regenerators (8, 9) and heat exchangers (14, 15) are arranged such that in the pressure vessel (1') there is also a piston liner (16) with the working volumes (5, 6, 7) leading overflow openings (17, 18, 19) and that in the pressure vessel (1 ') the heat exchanger (15) for the one heat transfer medium on the one hand the cold working volume (7) and on the other hand a space (70) limits in which the control gear (S) which is operatively connected to the pistons (2, 3) is arranged.

2. Machine according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the two pistons (2, 3) are provided with piston rods (20, 21) which engage together in the space (70),

REPLACEMENT LEAF in which energizable and elastic control elements for the piston movements are arranged.

3. Machine according to claim 1 or 2, so that the "hot" regenerator (8) is arranged integrated in the piston (2) and this essentially limits the hot working volume (6) on the piston side.

4. Machine according to one of claims 1 to 3, so that the burner-side end wall (23) of the pressure vessel (1 ') is provided on its peripheral edge with an annular cooling channel (24).

5. Machine according to claim 3 or 4, characterized in that the end wall (23), seen from the outside, concave ge¬ and the piston (2) with the integrated regenerator (8) to this curvature of the end wall (23) accordingly is adapted.

6. Machine according to one of claims 1 to 5, characterized in that the space (70) delimiting heat exchanger (15) to the piston (3), seen from the outside, also concave ge¬ and the piston (3) on the side of the cold working volume (7) is correspondingly curved.

7. Machine according to one of claims 1 to 6, characterized in that the connectable to a heating circuit heat exchanger (14) on both sides to the overflow opening (18) between the piston liner (16) and the pressure vessel wall (1 ") an¬ arranged and this heat exchanger (14th ) on the cold side (KS) the "cold" regenerator (9) is also connected upstream in the intermediate space (25) of the piston liner (16) and the pressure vessel wall (1 ").

i__i t -Η.3 <__ «- ^« _ — r « ^■ ' ^J

8. Machine according to claim 7, so that the remaining space (25) is filled with heat insulation material (27) while keeping clear of the inflow spaces (26) associated with the overflow openings (17, 18, 19).

9. Machine according to one of claims 5 to 8, so that the burner (22) is designed as a mushroom head burner adapted essentially to the concave curvature of the end wall (23).

10. Machine according to claim 1 or 9, so that the burner (22) is assigned a heat exchanger (28) for preheating the burner air.

11. Machine according to claim 2, characterized in that the piston rods (20, 21) with their piston rod ends (20 ', 21') between two the maximum piston stroke (H) correspondingly distant E-magnets (28, 29) and each piston rod end (20 ', 21') is arranged clamped between two compression springs (30, 31) supported against the walls of the space (70), the piston rod (20) of the piston (2 ) the piston rod (21) of the other piston (3), which is designed as a tube, passes through and the ends of the piston rod (20 ', 21') are provided with two-armed cross arms (20 ", 21"), each of which is between E-magnets (28, 29) and compression springs (30, 31) grip.

12. Machine according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the hot working volume (6) delimiting piston

(2) with a central piston extension (40) on its

REPLACEMENT LEAF the warm working volume (5) delimiting piston surface (2 ¹ ) is provided, which engages in a corresponding recess (41) of the other piston (3), the piston rod (20) on the bottom (42) of the piston extension (40) and the piston rod (21) are arranged on the bottom (43) of the recess (41).

13. Machine according to claim 12, so that the space delimited by the piston extension (40) and the recess (41) space (44) is connected via a bypass line to the operating gas-carrying interior of the machine.

14. Machine according to one of claims 1 to 13, characterized in that in the middle and stationary in the warm working volume (5) between the pistons (2, 3) is provided with a partition wall (32) provided with throughflow openings, which also the inflow space (25th ) divides between the two parts of the heat exchanger (14) and additional regenerators (33) are arranged in the flow openings.

15. Machine according to claim 6, so that the curvature of the heat exchanger (15), at least in the peripheral edge regions, is less than that of the surface of the piston (3) facing it.

16. Machine according to one of claims 1 to 15, so that the piston liner (16), which is preferably made of ceramic, is elastically mounted in the axial direction on the cold side (KS) of the pressure container (1 ').

17. Machine according to one of claims 1 to 16, characterized. that the heat exchanger (15) is pressure-tight but detachably arranged on the pressure vessel (1 ').

18. Machine according to one of claims 1, 2, 5 and 6, characterized in that the piston liner (16) as a heat exchange wall (16 *) between the heat transfer media and the gas side and with this wall (16 ') both the warm side (WS) as well as the cold side (KS) of the machine is detected, the wall (16 ') in the area of the piston (3) on the cold side on the gas side on the one hand enclosing the regenerator (9) and on the other hand the spaces (50, 50') carrying the heat transfer media ) separates from each other.

19. Machine according to claim 18, so that the wall (16 ') is provided with helically extending passages (51) which are pronounced towards the pressure vessel wall (1 ").

20. Machine according to claim 18 or 19, so that the regenerator (8) is arranged in the piston (2) or on the stationary gas side within the upwardly extending heat exchanger wall (16 ').

REPLACEMENT LEAF