CA2260228A1

CA2260228A1 - Air-conditioning installation

Info

Publication number: CA2260228A1
Application number: CA002260228A
Authority: CA
Inventors: Emil Gruniger
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-07-04
Filing date: 1997-07-02
Publication date: 1998-01-15
Also published as: EP0907871B1; PL183987B1; PL330954A1; DE59701474D1; EP0907871A1; ATE191969T1; AU3163597A; PT907871E; WO1998001711A1

Abstract

The invention relates to an air-conditioner having two heat-recovery units (10, 12), each of the heat-recovery units (10, 12) being traversed by a first flow channel system (14) and a second flow channel system (16). The heatrecovery units (10, 12) can be optionally operated for recuperative operation as a heat transmitter, and regenerative operation as a heat accumulator. Flap systems (60, 66, 68, 74, 78, 80 or 60', 66', 68', 74', 78', 80') associated with each of the heat-recovery units (10, 12) convey the supply flow (56) of surrounding air and the escaping flow (58) of outgoing air in such a manner that during recuperative operation both fluid streams flow through the heatrecovery units (10, 12), whereas during regenerative operation only one of the fluid streams respectively flows through, alternating in succession with each other, the one heat-recovery unit (10, 12) in each case, thereby achieving optimum use of the air-conditioner in the widest possible range of environmental conditions.

Description

Air-conditioning installation The present invention relates to an air-conditioning installation according to the preamble of claim 1.
An air-conditioning installation of this type is known, for example, from GB Patent No. 601023. This air-conditioning installation has a heat exchanger with two flow channel systems, one flow channel system having a first fluid stream flowing through it and, at the same time, the other flow channel system having a second fluid stream flowing through it. The first fluid stream is formed by used-up waste air which is withdrawn from a room. The second fluid stream is outside air which is taken in from the surroundings and is heated by the first fluid stream in the heat exchanger. Downstream of the heat exchanger, as seen in the direction of flow of the first fluid stream, part of the first fluid stream, which is controlled by a flap, is redirected and mixed with the heated, second fluid stream on the room side of the heat exchanger in order to be supplied to the room therewith. An air-conditioning installation of this type, which acts as a recuperator, is suitable, in particular, for air-conditioning rooms in a Central European climate inbetween seasons. Furthermore, the bypass connection allows the installation to be regulated easily to this effect. However, it has been found that air-conditioning installations of this type are not optimally suitable for use in the case of low and relatively high ambient temperatures.
An air-conditioning installation of a different type is known from DE-A-26 34 449 and the corresponding GB Patent No. 155 505. This air-conditioning installation has two heat accumulators each with a flow channel system. Controlled by a flap system, the first fluid stream flows through the flow channel system of one heat accumulator for a specific period of time and then flows through the flow channel system of the other heat accumulator for a further period of time, this alternating with the second fluid stream. The fluid stream with the higher temperature thus heats the heat accumulator which it flows through, and this heat accumulator then discharges said heat to the fluid stream with the lower temperature, in order to heat the same. Such air-conditioning installations, also referred to as regenerators, have an extremely good efficiency and are suitable, in particular, for use in the case of cold and relatively high ambient temperatures, for the purpose of air-conditioning rooms. In between seasons, these installations have the disadvantage, in particular, that moisture is also recovered when it is not desired.
Furthermore, EP-A-0 167 938 discloses a heat-exchanger and/or heat-accumulator body for use either in accordance with the recuperator principle or in accordance with the regenerator principle. The body comprises a stack of hollow-chamber plates, it being the intention for successive plates to be arranged in each case with mutually perpendicular channels for use in accordance with the recuperator principle and with mutually parallel channels for use in accordance with the regenerator principle.
Taking this prior art as the departure point, an object of the present invention is to provide an air-conditioning installation of the generic type which can be used with optimum efficiency in a large ambient-temperature range.
This object is achieved by an air-conditioning installation which has the features of claim 1.
The air-conditioning installation according to the invention can be operated both with recuperative action and with regenerative action. In the two modes of operation, use is made of the same heat-recovery units, which in one case serve as a heat exchanger and in the other case serve as a heat accumulator. An air-conditioning installation which, from low to high ambient temperatures, can be used optimally for room air-conditioning is provided by way of just an ~....

extremely small amount of additional outlay, in relation to the known air-conditioning installations.
Preferred embodiments of the air-conditioning installation according to the invention are specified in the dependent claims.
The invention will now be explained in more detail with reference to an exemplary embodiment illustrated in the drawing, in which, purely schematically:
Figure 1 shows a view of an air-conditioning installation according to the invention with the front wall of the housing assumed as being transparent;
Figure 2 shows a plan view of the air-conditioning installation shown in Figure 1, with the top wall assumed as being transparent;
Figure 3 shows a view of the air-conditioning installation shown in Figures 1 and 2, with a chain-dotted representation of the progression of the fluid streams in recuperative operation;
Figure 4 shows a plan view of the air-conditioning installation shown in Figures 1 and 2, with a chain-dotted representation of the progression of the fluid streams in recuperative operation;
Figure 5 shows, in an illustration which is the same as Figure 1, the air-conditioning installation in regenerative operation, with a chain-dotted representation of the progression of one fluid stream through one heat-recovery unit during one operating phase;
Figure 6 shows, in an illustration which is the same as Figure 5, the air-conditioning installation with a chain-dotted representation of the progression of the other fluid stream through the other heat-recovery unit during the same operating phase; and Figure 7 shows, in an illustration which is the same as Figure 2, the air-conditioning installation with a chain-dotted representation of the progression of the two fluid streams during the same operating phase as in Figures 5 and 6.

The air-conditioning installation shown in Figures 1 and 2 has two heat-recovery units 10, 12 each comprising two cross-flow plate heat exchangers 10', 10'' and 12', 12'' respectively, which are arranged directly one behind the other, as seen in the longitudinal direction L of the air-conditioning installation. Each heat-recovery unit 10, 12 thus has a first flow channel system 14 which runs through the two plate heat exchangers 10', 10'' and 12', 12'' in the longitudinal direction L, and a second flow channel system 16. The latter comprises channels 16' which run, in each plate heat exchanger 10', 10'', 12', 12'' at right angles to the first flow channel system 14, it being the case that the channels 16' of the cross-flow plate heat exchangers 10', 10'', 12', 12'', which are respectively assigned to a heat-recovery unit 10, 12, are connected in series by means of an intercepting and deflecting basin 18 arranged therebeneath, with the result that the corresponding fluid stream is routed in the form of a V through the heat-recovery unit 10 or 12.
The air-conditioning installation has a cuboidal housing 20 which lies horizontally and of which the interior, as seen in the longitudinal direction L, is subdivided, by a first transverse wall 22 and a second transverse wall 24, into two end sections 26, 28 and a central section 30, arranged between the transverse wall 22, 24. The central section is subdivided into two adjacent central parts 34, 34' by a vertical central-section intermediate wall 32, which runs in the longitudinal direction L. The heat-recovery unit 10 is arranged in the first central part 34 and the heat-recovery unit 12 is arranged in the second central part 34'. Each of the two end sections 26, 28 is subdivided into in each case two end chambers 38, 38' and 40, 40', which are arranged one above the other, by a horizontal end-section intermediate wall 36.

.... .

The end wall 42 of the housing 20, said end wall bounding the first end section 26, has a through-passage 44, which serves as a connection for the outside air AU and opens out into an air filter 46, which is arranged in the end chamber 38. Above the connection 44, the end wall 42 has a further through-passage, which serves as an expulsion-air connection 48 in order for the expulsion air FO flowing through the end chamber 38' to be directed, by way of a channel system (not shown) into the surroundings.
Similarly, the opposite end wall 42' has a through-passage which serves as a supply-air connection 50 in order for the supply air ZU flowing out of the end chamber 40 to be directed, by a further channel system (not shown either), to the interior of a building which is to be air-conditioned. Coming from the interior of the building is a further channel system (not shown either), which is connected to a waste-air connection 52 which connects this channel system to the end chamber 40'. Arranged in this end chamber 40' are further air filters 46', which are intended for filtering dust particles out of the waste-air stream AB.
A ventilator 54, 54' is arranged in each of the end chambers 40 and 40', these ventilators being intended for feeding an outside-air/supply-air stream 56 and/or waste-air/expulsion-air stream 58 (see Figures 3 to 7) through the heat-recovery units 10, 12.
The two heat-recovery units 10, 12 are connected to the end chambers 38, 38' and 40, 40' via flap systems such that they can be operated both with recuperative action and with regenerative action. In recuperative operation, the heat-recovery units 10, 12 serve as heat exchangers, it being the case that the outside-air/supply-air stream 56 is routed through the first flow channel system 14 and, at the same time, the waste-air/expulsion-air stream 58 is routed through the second flow channel system 16. In regenerative operation, the outside-air/supply-air stream 56 is . . ~, , . , ~

routed such that it flows through in each case the first and second flow channel systems 14, 16 of just one heat-recovery unit 10 or 12 during one operating phase lasting a specific period of time and flows through the flow channel systems 14, 16 of just the other heat-recovery unit 12, 10 during a following operating phase lasting a specific period of time, whereas the waste-air/expulsion-air stream 58 is routed conversely. In this case, the heat-recovery units 10, 12, through which one air stream 56 and the other air stream 58 flow alternately, serve as a heat accumulator.
Arranged in the first transverse wall 22, on both sides of the central-section intermediate wall 32, is a first flap system 60, 60', which is of dynamic design and connects the end chamber 38 to a corresponding first connection chamber 62 or 62', respectively, as long as the pressure in the end chamber 38 is greater than that in the relevant first connection chamber 62, 62'. One end of the first flow channel system 14 of the relevant heat-recovery unit 10, 12 opens out into the first connection chamber 62, 62'. The other end of the first flow channel system 14 opens out into a second connection chamber 64 or 64'.
Located in the second transverse wall 24, between said connection chambers 64 and 64' and the end chamber 40, is a second flap system 66, 66' which is designed to be motor-controlled.
On both sides of the central-section intermediate wall 32, the end chamber 40' can be connected to a third connection chamber 70 or 70' respectively via a third flap system 68, 68', which is arranged in the second transverse wall 24 and is likewise designed to be motor-controlled. One end of the second flow channel system 16 of the heat-recovery unit 10 or 12 opens out into the third connection chamber 70 or 70', respectively. At the other end, the second flow channel systems 16 open out into a fourth connection chamber 72 or 72' in each case. Located in . ... .. . . . . . ...

the first transverse wall 22, between said fourth connection chambers 72, 72' and the end chamber 38', is a fourth flap system 74 or 74', respectively, which is of dynamic design. The fourth flap systems 74, 74' are located in the open position when the pressure in the fourth connection chamber 72, 72' is higher than the pressure in the end chamber 38'.
The first connection chambers 62, 62i are separated off from the corresponding fourth connection chambers 72, 72' by a partition wall 76 and can be connected to one another via a further flap system 78, which is arranged in said partition wall 76 and is designed to be motor-controlled. In the same way, the second connection chambers 64, 64' are separated off from the corresponding third connection chambers 70, 70' by a further partition wall 76' and can be connected via a further flap system 80 or 80', respectively, which is arranged in said partition wall 76'.
20Finally, the third connection chambers 70, 70' are separated off from the corresponding fourth connection chambers 72, 72' by a further partition wall 82. In each case are bypass flap system 84, 84', which is designed to be motor-controlled, is arranged in said partition wall 82.
Located in the interior of the trough-like intercepting and deflecting basin 18, and above the plate heat exchangers 10'', 12'' are nozzle bars 86 which are intended for spraying with water, for adiabatic cooling, the plate heat exchangers 10', 10'' and 12', 12'' from beneath, and the plate heat exchangers 10'', 12'' from above in addition, as well as the fluid stream routed through the second flow channel system 16. The water which is not taken up by the fluid stream flows back into the intercepting and deflecting basin 18, where it is removed by means of a pump 88 and supplied to the nozzle bars 86 again.
90 designates a compressor which is connected to evaporator/condenser units 92 in the end chambers 38' and 40. The compressor 90 and said evaporator/condenser units 92 form an integrated, additional heating and cooling assembly, which can be switched over and is designed in the manner of a heat pump with reversible operating-fluid circulation. It should be mentioned that, depending on the purpose for which the air-conditioning installation is used, it is possible to dispense with the additional heating and cooling assembly 90, 92 or to provide a heating or cooling assembly which cannot be switched over.
Likewise, the device for adiabatic cooling is not essential, but it is advantageous if one is provided.
Instead of a built-in heating and/or cooling assembly, it is also conceivable to use external heating and/or cooling assemblies.
The way in which the air-conditioning installation which has been described above and is shown in Figures 1 and 2 functions will now be described, in the different modes of operation, with reference to Figures 3 to 7. These figures correspond to Figures 1 and 2, and the same parts of the air-conditioning installation are provided with the same designations and are only included in Figures 3 to 7 insofar as is necessary to aid understanding.
Assuming that a temperature of approximately 20~C is to be maintained inside a room or building which is to be air-conditioned, the air-conditioning installation according to the invention is advantageously operated as follows: in the case of outside temperatures of approximately -20~C to approximately +5~C in regenerative operation, from approximately 5~C to approximately 15~C in recuperative operation preferably with regulated heat recovery, from approximately 15~C to approximately 25~C and, depending on humidity, up to 32~C in recuperative operation with adiabatic cooling, and in the case of higher temperatures additionally with a built-in cooling assembly; in the case of very high tropical temperatures with high levels of humidity in the outside air in regenerative operation with cold recovery and with a built-in cooling assembly. In the case of very low outside temperatures, or in the case where only minimal additional quantities of heat are released in the air-conditioned room, an additional heating assembly may be provided. If necessary, it is possible to install an additional heating and cooling assembly which can be switched over.
The routing of the outside-air/supply-air stream 56 and waste-air/expulsion-air stream 58 in recuperative operation is shown in Figures 3 and 4. The second and third flap systems 66, 66' and 68, 68', respectively, are located in the open position, whereas the further flap systems 78, 78' and 80, 80' as well as the bypass flap system 84, 84' are located in the closed position. If the ventilators 54, 54' are set in operation, the first and fourth flap systems 60, 60' and 72, 72', respectively, open automatically. The ventilator 54 takes in outside air AU, which passes through the air filter 46 into the end chamber 38 and, from there, through the two first flap systems 60, 60' into the first connection chambers 62 and 62'. From there, the outside air flows through the first flow channel system 14 of the heat-recovery units 10 and 12 and emerges into the second connection chambers 64, 64'. From there, the air stream passes through the second flap systems 66, 66', which are open, into the end chamber 40, where it flows through the ventilator 54 and is supplied, as supply-air stream ZU to the room which is to be air-conditioned. At the same time, the ventilator 54' removes waste air AB from the room which is to be air-conditioned, said waste air passing through the air filter 46' into the end chamber 40'.
The third flap systems 68, 68', which are open, allow the waste-air stream to pass into the two third connection chambers 70, 70' from where, deflected by the second flow channel system 16 of the heat-recovery units 10 and 12 and in the intercepting and deflecting basin 18, it passes into the fourth connection chambers 72, 72'. From here, the air stream flows, as expulsion air FO, through the fourth flap systems 74, 74' into the end chamber 38' and, from there, into the surroundings.
If the ambient temperature is lower than the temperature of the room whlch ls to be alr-condltloned, in the heat-recovery units 10 and 12, whlch then act as a heat exchanger, heat ls removed from the waste-alr/expulslon-air stream 58 and transferred to the outside-air/supply-air stream 56, as a result of which the latter is heated up. If, on the other hand, the outslde temperature is hlgher than the desired temperature in the room which is to be alr-condltioned, heat is transferred from the outslde-alr/supply-alr stream 56 to the waste-alr/expulslon-alr stream 58, which results in the supply alr ZU belng cooled. At the same time, it is possible to cool the waste-air/expulsion-air stream adiabatically and the heat-recovery units 10, 12 by spraying them with water by means of the nozzle bars 86, as a result of whlch the outslde-alr/supply-alr stream 56 ls cooled lndirectly.
For temperature regulation in the room whlch ls to be alr-condltloned, lt ls posslble to regulate the bypass flap systems 84, 84'. As a result, part of the waste-alr/expulsion-alr stream is routed past the heat-recovery units 10, 12.
It is also conceivable to open the further flap systems 80, 80', as required, in order to supply part of the waste-air/expulsion-alr stream 58, before lt flows through the heat-recovery unlts 10, 12, to the outslde-alr/supply-alr stream 56 and to dlrect it, mlxed wlth the latter stream 56, to the room whlch ls to be alr-condltloned.
The routlng of the outside-alr/supply-alr stream 56 and waste-alr/expulslon-alr stream 58 ln regeneratlve operatlon is shown in Figures 5 to 7. In a first operatlng phase, during a speclflc perlod of tlme, the outslde-alr/supply-alr stream 56 ls routed just through one heat-recovery unlt 10 or 12, whereas, at the same time, the waste-air/expulsion-air stream 58 is routed just through the other heat-recovery unit 12 or 10, respectively. In a following, second operation phase, during a specific period of time, the two streams 56, 58 are then routed through the respectively other heat-recovery unit 10 or 12. This periodic alternation takes place at a frequency of approximately 30 to approximately 60 seconds.
Figures 5 to 7 show that operating phase in which the outside-air/supply-air stream 56 is routed through the heat-recovery unit 12 and the waste-air/expulsion-air stream 58 is routed through the heat-recovery unit 10. As can be gathered from Figures 6 and 7, the second flap system 66', which is assigned to the heat-recovery unit 12, and the further flap systems 78' and 80', which are likewise assigned to said heat-recovery unit 12, are located in the open position, whereas the third, fourth and bypass flap systems 68', 74' and 84', which are assigned to said heat-exchange unit 12, are located in the closed position. If ventilator 54 is in operation, the corresponding first flap system 60' is automatically in the open position, and the outside air AU taken in by the air filter 46 passes from the end chamber 38 into the first connection chamber 62'. From here, part of the fluid stream flows through the first flow channel system 14, while the rest of the fluid stream passes through the further flap system 78' into the fourth connection chamber 72' and, from here, flows through the second flow channel system 16. The latter part of the fluid stream passes into the third connection chamber 70' and, from this, passes through the open flap system 80' into the second connection chamber 64', where the two part-streams combine and pass through the second flap system 66 into the end chamber 40, from where they are supplied by means of the ventilator 54, as supply-air stream ZU, to the room which is to be air-conditioned.
As a result of the negative pressure in the fourth connection chamber 72' in relation to the pressure in the end chamber 38', the fourth flap system 74' is closed automatically.
At the same time, as is shown in Figures 5 and 7, the waste-air/expulsion-air stream 58 is routed just through the heat-recovery unit 10. For this purpose, the first and second flap systems 60, 66, which are assigned to the heat-recovery unit 10, are closed and the third and fourth flap systems 68, 74 and the corresponding further flap systems 78, 80 are open. The waste air AB taken in by the ventilator 54' and passing through the air filter 46' into the end chamber 40' passes, from here, into the third connection chamber 70, where the fluid stream divides up. Part of the fluid stream flows through the second flow channel system 16 in the form of a U and passes directly into the fourth connection chamber 72, whereas the rest of the fluid stream passes through the further flap system 80 into the third connection chamber 70 and, from here, flows through the first flow channel system 14. The latter part of the fluid stream then passes from the first connection chamber 62 through the further flap system 78, which is open, likewise into the fourth connection chamber 72, where the two part-streams combine to form an expulsion-air stream FO, which passes through the automatically opened, fourth flap system 74 into the end chamber 38' and, from the latter, into the surroundings. Since the pressure in the first connection chamber 62 is higher than in the end chamber 38, the first flap system 60 is closed automatically.
Following completion of one operating phase, the flap systems assigned to one heat-recovery unit 10 are displaced into that position which, in the previous operating phase, was assumed by the flap systems assigned to the other heat-recovery unit 12, and vice versa. This results in the situation where, during one operating phase, the warmer air stream, be this the outside-air/supply-air stream 56 or waste-air/expulsion-air stream 58, heats up the corresponding heat-recovery unit 10 or 12, which then acts as a heat accumulator, while the other air stream removes heat from the previously heated-up heat-recovery unit 12 or 10, respectively.
Since the air-conditioning installation is operated with regenerative action in particular in the case of extreme outside temperatures, it is possible, if necessary and if a built-in heating and cooling assembly 90, 92 is provided, either additionally to withdraw heat from the waste-air/expulsion-air stream 58 and supply said heat to the outside-air/supply-air stream 56, for additional heating, or to use the additional heating and cooling assembly 90, 92 to withdraw heat from the outside-air/supply-air stream 56, in order to cool the latter, and supply said heat to the waste-air/expulsion-air stream.
It should also be mentioned in conjunction with regenerative operation that it is possible, by means of control of the bypass flap systems 84, 84', for part of the outside-air/supply-air stream 56 and/or of the waste-air/expulsion-air stream 58 to be directed past the corresponding heat-recovery unit 10, 12. This permits extremely efficient regulation.
Of course, it is conceivable for the heat-recovery units and the flap systems and ventilators tobe arranged differently from the arrangement shown in the figures. It is, of course, also conceivable for each heat-recovery unit to have just a single plate heat exchanger, or more than two plate heat exchangers, or heat exchangers which are constructed differently and are also suitable for heat accumulation.
For the sake of completeness, it should also be mentioned that the end chambers 38, 38', 40, 40' are not essential. It is conceivable for pipelines to be routed directly to the transverse walls 22, 24, and thus for the transverse walls to form the end walls of the air-conditioning installation.
It is also conceivable to allow the air streams, in recuperative operation, to flow just CA 02260228 l998-l2-30 through one of the two heat-recovery units. In this case, however, greater flow speeds and a higher flow resistance have to be accepted. The same applies if, in regenerative operation, the air streams were to be routed through in each case one of the flow channel systems.

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Claims

claims

1. An air-conditioning installation having a heat-recovery unit (10, 12) which is intended for the through-flow of two fluid streams and has two flow channel systems (14, 16), wherein the air-conditioning installation has at least two heat-recovery units (10, 12), which can be operated optionally, for recuperative operation, as a heat exchanger and, for regenerative operation, as a heat accumulator, it being the case that, in recuperative operation, the two flow channel systems (14, 16) of a heat-recovery unit (10, 12) have in each case one of the fluid streams (56, 58) flowing through them at the same time and, in regenerative operation, alternately one heat-recovery unit (10, 12) and the other heat-recovery unit (12, 10), one after the other, have the two fluid streams (56, 58) flowing through them.

2. The air-conditioning installation as claimed in claim 1, wherein one fluid stream (56) is an outside-air/supply-air stream and the other fluid stream (58) is a waste-air/expulsion-air stream.

3. The air-conditioning installation as claimed in claim 1 or 2, wherein, in recuperative operation, the two heat-recovery units (10, 12) are connected in parallel.

4. The air-conditioning installation as claimed in one of claims 1 to 3, wherein, in regenerative operation, the two flow channel systems (14, 16) of each of the heat-recovery units (10, 12) are connected in parallel.

5. The air-conditioning installation as claimed in one of claims 1 to 4, which comprises a spray system (86, 88) which is intended for spraying the heat-recovery units (10, 12) and the waste-air/expulsion-air stream (58) and is provided for adiabatic cooling.

6. The air-conditioning installation as claimed in one of claims 1 to 5, wherein one flow channel system (14) of each heat-recovery unit (10, 12) is connected, in a disengageable manner, to an outside-air connection (44) via a first flap system (60, 60'), on the one hand, and to a supply-air connection (50) via a second flap system (66, 66'), on the other hand, and the other flow channel system (16) is connected, in a disengageable manner, to a waste-air connection (52) via a third flap system (68, 68'), on the one hand, and to an expulsion connection (48) via a fourth flap system (74, 74'), on the other hand, and wherein the two flow channel systems (14, 16) of each heat-recovery unit (10, 12) can be connected to one another at both ends via a further flap system (78, 78', 80, 80') in each case.

7. The air-conditioning installation as claimed in claim 6, wherein the waste-air connection (52) and the expulsion-air connection (48) can be connected to one another via a bypass flap system (84, 84') in order to bypass the heat-recovery units (10, 12).

8. The air-conditioning installation as claimed in claim 6 or 7, wherein the second and third flap systems (66, 66', 68, 68'), the further flap systems (78, 78', 80, 80') and, if appropriate, the bypass flap system (84, 84') are motor-controlled, and the first and fourth flap systems (60, 60', 74, 74') are of dynamic design.

9. The air-conditioning installation as claimed in one of claims 5 to 8, wherein it has a cuboidal housing (20) with, as seen in the longitudinal direction (L), two transverse walls (22, 24) which separate off a central section (30), arranged between the partition walls (22, 24), from end sections (26, 28), it being the case that the central section (30) is subdivided into two central parts (34, 34') by a central-section intermediate wall (32), which runs in the longitudinal direction (L), and each of the end sections (26, 28) is subdivided into two end chambers (38, 38'; 40, 40') by in each case one end-section intermediate wall (36), which runs in the longitudinal direction (L) and transversely with respect to, preferably at right angles to, the central-section intermediate wall (32), a heat-recovery unit (10, 12) is arranged in each central part (34, 34'), in each case the first flow channel system (14) opens out, on the one hand, into a first connection chamber (62, 62') and, on the other hand, into a second connection chamber (64, 64') and the second flow channel system (16) opens out, on the one hand, into a third connection chamber (70, 70') and, on the other hand, into a fourth connection chamber (72, 72'), in the relevant central part (34, 34'), said connection chambers can be connected to the appropriate end chambers (38, 38', 40, 40') via the associated flap systems (60, 60', 66, 66', 68, 68', 74, 74') arranged in the transverse walls (22, 24), and the first connection chamber (62, 62') can be connected to the fourth connection chamber (72, 72'), and the second connection chamber (64, 64') can be connected to the third connection chamber (70, 70'), via in each case one of the further flap systems (78, 78', 80, 80') and, if appropriate, the third connection chamber (70, 70') can be connected to the fourth connection chamber (72, 72') via the bypass flap system (84, 84').

10. The air-conditioning installation as claimed in one of claims 1 to 9, wherein each heat-recovery unit (10, 12) has two cross-flow plate heat exchangers (10', 10'', 12', 12''), which are arranged in series and of which the mass serves as a heat accumulator in regenerative operation.

11. The air-conditioning installation as claimed in one of claims 1 to 10, which comprises an additional heating or cooling assembly (90, 92) which can preferably be switched over.