GB1588305A

GB1588305A - Effect air-conditioning installation

Info

Publication number: GB1588305A
Application number: GB9438/78A
Authority: GB
Original assignee: Air Industrie SA
Current assignee: Air Industrie SA
Priority date: 1977-03-11
Filing date: 1978-03-09
Publication date: 1981-04-23
Also published as: FR2394761B2; DE2810438A1; DE2810438C2; ATA174578A; AT360581B; FR2394761A2

Description

(54) PELTIER EFFECT AIR-CONDITIONING INSTALLATION (71) We, AIR INDUSTRIE, a body corporate organised under the laws of France, of 19-21 Avenue Dubonnet, 92401 Courbevoie, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to PELTIER effect air-conditioning installations, i.e. air-conditioning installations comprising thermo-electric batteries formed from thermo-elements mounted between heat exchange walls arranged in the form of an exchanger and which are maintained at different temperatures when a DC electric current flows through the thermoelements.

In such an installation, a current of heated air or a current of cooled air can be generated in relation to the ambient temperature outside the accomodation unit to be air-conditioned depending on the direction of the DC current which flows through the thermo-elements.

Now, it is known that DC current - especially at the relatively low voltage (of the order of 50 to 200 volts or more, for example) with which the thermo-electric batteries are supplied - is not normally available in or in the vicinity of accomodation units, fixed or mobile, which it is desired to air-condition.

Therefore, it is necessary to provide, for supplying the thermo-electric batteries, convertor means for passing from an available electric current (AC, pseudo AC, even DC or pseudo DC), to a low voltage DC current (50 to 200 volts).

For example, with a low voltage (220 volts) AC current, these convertor means may be formed by a simple rectifier.

For example again, with an AC current of a higher voltage (1500 volts), these convertor means must comprise first of all a transformer reducing the AC voltage to a value compatible with supplying the thermo-electric batteries, and then a rectifier transforming this low AC voltage into a low DC voltage.

In any case, whatever the convertor means used, it is necessary to provide for their cooling, preferably by a forced air flow around the convertor means.

The invention has as its object an advantageous integration of these convertor means in the air-conditioning installation.

The air-conditioning installation of the invention comprises : at least one thermo-electric battery defining an ambient air circuit and an air circuit for the conditioning air (air for airconditioning to be heated or cooled in relation to the ambient air); first fan means for causing the ambient air to flow; second fan means for causing the conditioning air to flow towards its user station (accomodation unit to be air-conditioned); and convertor means for the low voltage DC electric supply for the thermoelectric battery, these convertor means being themselves supplied with electric current; at least part of said convertor means being arranged so as to be bathed dry the flow of ambient air, and it is characterised by the fact that it is arranged so that, on the one hand, these convertor means are located upstream of the thermo-electric battery in relation to the direction of flow of the ambient air when the installation is heating the air for air-conditioning and, on the other hand, these convertor means are located downstream of the thermoelectric battery in relation to the direction of flow of the ambient air when the installation is cooling the air for air-conditioning.

With this arrangement, it is pointless to provide special cooling means for the covertor means, since these latter are bathed - either in the ambient air flow which issues from the thermo-electric battery (installation cooling the air for air-conditioning,-a flow the temperature of which has slightly increased while passing through said battery, but the delivery rate of which is high, which allows a satisfactory cooling effect to be obtained,-or in the ambient air-flow just before it enters the thermo-electric battery (installation heating the air for air conditioning), this flow having a low delivery rate but the temperature of which is the ambient temperature, which again allows a satisfactory cooling effect to be obtained for, in this mode of operation the ambient temperature is low since it is desired to heat the air for air-conditioning.

The ratio between the high ambient air delivery rate (installation cooling the air for air conditioning) and the low ambient air delivery rate (installation heating the air for air-conditioning) may be approximately within the limits 3 to 1 and 7 to 1.

Experience shows in fact that it is desirable to operate the thermo-electric battery with a low ambient delivery rate when the installation is heating the air for air-conditioning, whereas on the contrary the ambient air delivery rate must be as high as possible when the installation is cooling the air for air-conditioning.

Another advantage of this arrangement, which exists when the installation is heating the air for air-conditioning, is to be found in the increase in the temperature of the ambient air after bathing the convertor means and before its entry into the thermo-elastic battery.

This increase of the input temperature of the ambient air allows, - on the one hand, the yield of the thermo-electric battery to be increased (smaller divergence between the temperature of the hot source and the temperature of the cold source of the heat pump formed by the thermo-electric battery), - and, on the other hand, the risks of icing to be reduced in the thermo-electric battery during the cooling to which the ambient air is subjected.

Finally, it should be pointed out that the invention enables a particularly compact airconditioning installation to be constructed and to be given a form adapted to facilitate its mounting.

It should furthermore be pointed out that these last two technological advantages (compactness and adaptation of shape) are particularly attractive when the invention is applied to the air-conditioning of vehicles, particularly railway vehicles : in this latter application, the convertor means are of the complex type (rectifier + chopper + transformer + rectifier) and their cooling corresponds to a considerable heat energy which is easily exhausted by the ambient air leaving or entering the thermoelectric battery and which contributes to increasing beneficially the temperature of the ambient air at the inlet of the thermo-electric battery when the air for air-conditioning is to be heated.

According to a particular arrangement of the invention, the convertor means may be formed by at least two separate convertor asssemblies one of which convertor assemblies is arranged so as to be bathed by the ambient air-flow and to be located upstream of the thermo-electric battery in relation to the direction of ambient air flow when the installation is heating the air for air-conditioning, and the other convertor assembly is arranged so as to be bath by a flow of air extracted from the accomodation unit to be air-conditioned through third fan means.

The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 of these drawings is a schematic view of an air-conditioning installation in accordance with a first embodiment shown in operation for heating the air for air-conditioning.

Figure 2 shows the installation of Figure 1 in operation for cooling the air for air-conditioning.

Figure 3 is a schematic view of an air-conditioning installation according to another embodiment of the invention, more particularly designed for the air-conditioning of a railway vehicle, the installation being shown in operation for heating the air for air-conditioning.

Figure 4 shows the installation of Figure 3 in operation for cooling the air for air-conditioning.

Figure 5 is a schematic view of an air-conditioning installation in accordance with another embodiment of the invention more particularly designed for the air-conditioning of a railway vehicle, the installation being shown in operation for heating the air for airconditioning.

Figure 6 shows the installation of Figure 5 in operation for cooling the air for air-conditioning.

Figure 7 and 8 show variations of the installations shown in Figure 5 and 3 respectively.

Figure 9 is a schematic view of an airconditioning installation in accordance with another embodiment, shown in operation for heating the air for air-conditioning.

Figure 10 shows the installation of Figure 9 in operation for cooling the air for air-conditioning.

Figure 11 is a schematic view of an airconditioning installation in accordance with another embodiment of the invention, more particularly designed for the air-conditioning of a railway vehicle, the installation being shown in operation for heating the air for airconditioning, and Figure 12, finally, shows the installation of Figure 11 in operation for cooling the air for air-conditioning.

In these figures, there is then shown schematically an air-conditioning installation comprising thermo-electric batteries 1. These thermo-electric batteries 1 are themselves formed by an assembly of units (not shown but which may be constructed as indicated in patent specification No. 1 546 418 obtained by stacking heat exchange elements comprising one or more thermo-elements, heat exchange walls and exchange surfaces.

The heat exchange walls associated with the corresponding exchange surfaces form heat exchangers defining a circuit through which passes the ambient air and a circuit through which passes the air for air-conditioning, to be heated or cooled with respect to the ambient air.

First fan means 2 are provided for causing the ambient air to flow in both directions, these first fan means being advantageously arranged to generate a delivery rate, during operation for cooling the air for air-conditioning higher (of the order of 3 to 7 times) than the delivery rate when operating for heating the air for airconditioning.

Preferably, these first fan means 2 are formed by one (or more) axial flow fans driven by a motor capable of rotating it (or them) either at high speed, in the suction direction (fan providing the high delivery rate for operation for cooling the air for air-conditioning), - or at low speed, in the discharge direction (fan providing the low delivery rate during operation when heating the air for air-conditioning).

Second fan means 3 are provided for causing the air for air-conditioning to flow toward the accomodation unit 4 to be air-conditioned.

Preferably, these second fan means 3 are formed by one (or more) fans, for example of the centrifugal type, which take advantage of the change of direction inherent in this type of fan. This being so, these second fan means 3 are disposed at the outlet of thermo-electric battery 1.

Convertor means 5 are provided for supplying the thermo-electric battery 1 with a low voltage DC current, these convertor means 5 being themselves supplied with an AC, pseudo AC, even DC or pseudo DC voltage.

These convertor means 5 are disposed so as to be bathed by the flow of ambient air and to be located upstream of the thermo-electric battery 1 in relation to the direction of ambient air flow when the installation is heating the air for air-conditioning.

Convertor means 5 may be disposed between thermo-electric battery 1 and the first fan means 2 (Figures 1 and 2 and Figure 3 and 4).

According to a reverse arrangement, the first fan means 2 are disposed between thermoelectric battery 1 and convertor means 5 (Figures 5 and 6).

An inverter device 6 is provided between the convertor means 5 and the thermo-electric batter 1 for inverting the direction of the DC current in the thermo-elements when passing from operation for heating the air for airconditioning to operation for cooling the air for air-conditioning.

The first fan means 2 are fitted with a switch device 7 for providing either a high ambient air delivery rate in a given direction for operation for cooling the air for air-conditioning or a high ambient air delivery rate in the opposite direction for operation for heating the air for airconditioning.

In Figures 1 and 2, there is shown an airconditioning installation for an accomodation unit 4 (or several units 4), this installation comprising a single thermo-electric battery 1.

A recovery duct 8 may be provided between the accomodation unit 4 to be air-conditioned the accomodation unit 4 to be air-conditioned and the supply duct 9 for supplying the air for air-conditioning to the thermo-electric battery 1.

This recovery duct 8 may comprise two branches 8a and 8b each provided with a valve Va and Vb for directing a part of the air taken from the accomodation unit 4 to be air-conditioned into the ambient air flow.

When the air for air-conditioning is heated (Fig. 1), the valve Va of the branch 8a is open and the valve Vb of the branch 8b is closed; a part of the air taken from the accomodation unit 4 to be air-conditioned is directed into the ambient air flow before it enters the thermoelectric battery 1.

When the air for air-conditioning is cooled (Fig. 2), the valve Va of the branch 8a is closed and the valve Vb of the branch 8b is open, a part of the air taken from the accomodation unit 4 to be air-conditioned is directed into the ambient air flow before it enters the thermoelectric battery 1.

In Figures 3 and 4, there is shown an airconditioning installation for an accomodation unit 4 formed by a railway vehicle (a passenger car for example of the coach type), this installation comprising four thermo-electric batteries 1, only two of which are shown in Figures 3 and 4 which show only half of the vehicle.

The two thermo-electric batteries 1 of each half of the vehicle are disposed longitudinally, one on each side of the central longitudinal axis of the vehicle.

Convertor means 5 are disposed axially between the two thermo-electric batteries 1, and the first fan means 2 are disposed axially, preferably towards the end of two batteries which faces towards the end of the considered half of the vehicle.

For the ambient air flow, there are provided two lateral ducts or apertures 10 (one per battery) and a central duct 11.

For the flow of the air for air-conditioning, there are provided - to supply the air for airconditioning to the thermo-electric batteries 1, a recovery duct 12 in the vehicle, and two lateral ambient air supply ducts 13 (one per battery), - and, for distribution ducts 14 (one per battery), disposed laterally.

In Figures 5 and 6, there is shown an airconditioning installation for an accomodation unit 4 formed by a railway vehicle (a passanger car for example of the coach type), this installation comprising eight thermo-electric batteries 1, only four of which are shown in Figures 5 and 6 which show only half of the vehicle.

The four thermo-electric batteries 1 of each half of the vehicle are disposed longitudinally, in pairs, one pair on each side of the axis of the vehicle, the batteries of the same pair being disposed as an extension of each other.

Convertor means 5 and first fan means 2 are disposed axially, preferably towards the end of the battery which faces towards the end of the considered half of the vehicle.

For the ambient air flow, there are provided, on the one hand, two lateral ducts or apertures 15 on one side and two lateral ducts or apertures 15 on the other side (i.e. one per battery), and, on the other hand, a central duct 16.

For the flow of the air for air-conditioning, there are provided - for supplying the air for air-conditioning to the thermo-electric batteries, a recovery duct 17 in the vehicle and two lateral ambient air supply ducts 18 (one per pair of batteries), disposed as an extension of each other, the batteries of the same pair being thus supplied through their ends which are facing each other, the batteries of the same pair being thus supplied through their ends which are facing each other, -- and for distributing the air for air-conditioning from the thermo-electric batteris 1, four distribution ducts 19 (one per battery) disposed laterally and being interconnectable.

As stated above the second fan means 3 may be disposed at the outlet of the thermo-electric battery 1.

It should be pointed out that these second fan means 3 may also be disposed at the inlet of the thermo-electric battery 1.

This arrangement is particularly advantageous when recourse is had to the embodiment of the invention shown in Figures 5 and 6.

In these circumstances, and as shown in Figure 7 in which the same reference designate the same elements as in Figure 5, the second fan means 3 are advantageously formed by a fan having two opposite outputs disposed respectively facing the two ends of the thermoelectric batteries 1 of the same pair which face each other.

Arrows F1 and F2 indicate the ambient air flow, respectively when heating the air for airconditioning (Figures 1, 3 and 5) and when cooling the air for air-conditioning (Figures 2, 4and6).

This air for air-conditioning flows in the direction shown by arrows G.

There is also shown by arrows H1 and H2 the direction of rotation of the fan 2, in the case of heating the air for air-conditioning (Figures 1, 3 and 5) and in the case of cooling the air for air-conditioning (Figures 3, 4 and 6) respectively.

The supply polarity for each thermo-electric battery 1 is shown at terminals A and B of the battery concerned. This polarity is positive for terminal A and negative for terminal B when cooling the air for air-conditioning (Figure 1, 3 and 5) and negative for terminal A and positive for terminal B when cooling the air for air-conditioning (Figures 2, 4 and 6).

Both on the embodiment illustrated in Figures 3 and 4 and in that illustrated in Figures 5 and 6, it is possible and advantageous to fit the air conditioning installation below the railway vehicle.

It will be noted moreover that the embodiment illustrated in Figures 5 and 6, in which the installation comprises eight thermo-electric batteries is particularly advantageous because each thermo-electric battery has a high yield because of its short length in the flow direction of the air for air-conditioning.

It has been previously pointed out that convertor means 5 could be located on one side or the other in relation to the first fan means 2.

According to a variation shown in Figure 8 in which the same references designate the same elements as in Figure 3, the convertor means 5 are formed by two assemblies 5a and 5b disposed one on each side of first fan means 2.

Generally, one of these assemblies houses the high voltage part and the other assembly houses the low voltage part.

In these circumstances, the high voltage assembly 5a is located on the outside in relation to the fan means 2 and the low voltage assembly 5b is located on the inside in relation to the fan means 2.

As shown in Figures 9 and 10, the convertor means are formed by two separate convertor assemblies 5a and 5b, connected in series from the electrical point of view.

The convertor assembly 5a is arranged so as to be bathed by the ambient air flow and to be located upstream of the thermo-electric battery 1 in relation to the direction of the ambient air flow when the installation is heating the air for air-conditioning.

The convertor assembly 5 b is arranged so as to be bathed by an air flow extracted from the accomodation unit 4 to be air-conditioned by a third fan means 30. This flow of air extracted from the accomodation unit 4 to be air-conditioned flows in a duct 31.

This air extracted from the accomodation unit 4 to be air-conditioned after bathing the convertor assembly 5b, is directed into the ambient air circuit, upstream of the thermoelectric battery 1 in relation to the direction of flow of the ambient air when the installation is heating the air for air-conditioning.

The installation shown in Figures 11 and 12 illustrates a particular application of the invention relative to an air-conditioning installation for an accomodation unit 4 formed by a railway vehicle (a passage car for example of the coach type), this installation comprising four thermo-electric batteries 1, only two of which are shown in Figures 11 and 12 and only show half of the vehicle.

The two thermo-electric batteries of each half of the vehicle are disposed longitudinally one on each side of the axis of the vehicle.

For the flow of ambient air, there are provided two lateral ducts or apertures 10 (one per battery) and a central duct 11.

For the flow of the air for air-conditioning, there are provided - for supplying the air for air-conditioning to the thermo-electric batteries 1, a recovery duct 12 in the vehicle and two lateral ambient air supply ducts 13 (one per battery), - and, for distributing the air for airconditioning from the thermo-electric batteries 1, two distribution ducts 14 (one per battery), disposed laterally.

As shown in Figures 11 and 12, the convertor means are formed by a low voltage convertor assembly Sa and two high voltage convertor assemblies 5b, connected in series from the electrical point of view.

The low voltage convertor assembly 5a is disposed axially between the two thermoelectric batteries 1 and the first fan means 2 are disposed axially, preferably towards the end of the two batteries which faces towards the end of the considered half of the vehicle.

Such being the case, this low voltage convertor assembly 5a is arranged so as to be bathed by the ambient air flow and to be located upstream of the thermo-electric battery 1 considered in relation to the flow direction of the ambient air when the installation is heating the air for the air-conditioning.

The two high voltage convertor assemblies 5b are arranged so as to be bathed by a flow of air extracted from the accomodation unit 4 to be air-conditioned by a third fan means 30.

This flow of air extracted from the accomodation unit 4 to be air-conditioned flows in a succession of ducts 32,33,34 and 35.

This air extracted from the accomodation unit 4 to be air-conditioned is directed, after bathing the two high voltage convertor assemblies 5b, into ambient air circuit, upstream of the thermo-electric battery 1 considered in relation to the direction of flow of the ambient air when the installation is heating the air for air-conditioning.

From the constructional point of view, it will be noticed that - the duct 32 connects an intake opening 36 emerging in the accomodation unit 4 to be air-conditioned to the third fan means 30, - the duct 33 connects the third fan means 30 to the first of the two first high voltage convertor assemblies 5b, - the duct 34 connects this high voltage convertor assembly 5b to the other high voltage convertor assembly 5b, - and the duct 35 connects this high voltage convertor assembly 5b to the central duct 11 into which said duct 35 emerges laterally.

According to the illustrated embodiments of the invention, on the one hand, in Figures 9 and 10 and, on the other hand, in Figures 11 and 12, an inverter device 6 is provided between the convertor assembly 5a and the thermoelectric battery 1 for inverting the direction of the DC current in the thermo-elements when changing over from operation for heating the air for air-conditioning to operation to cooling the air for air-conditioning.

The first fan means 2 are fitted with a switch device 7 for providing, either a high ambient air delivery rate in a given direction for operation for cooling the air for air-conditioning, or a high ambient air delivery rate in the opposite direction for operation for heating the air for air conditioning.

Referring to Figures 9 to 12, arrows F1 and F2 show the flow of ambient air when heating the air for air-conditioning (Figures 1 and 3) and when cooling the air for air-conditioning (Figures 2 and 4) respectively.

This air for air-conditioning flows in the direction indicated by arrows G.

There is also shown by arrows H1 and H2 the direction of rotation of fan 2 when heating the air for air-conditioning (Figures 1 and 3) and when cooling the air for air-conditioning (Figures 10 and 12) respectively.

The supply polarity for the thermo-electric battery 1 is indicated at terminals A and B of this battery. This polarity is positive for terminal A and negative for terminal B when heating the air for air-conditioning (Figures 9 and 11), and negative for terminal A and positive for terminal B when cooling the air for air-conditioning (Figures 10 and 11).

Finally, there is provided an air-conditioning installation which presents a certain number of advantages, of which the following may be mentioned: - it is not necessary to provide special means for cooling the convertor means - the yield of the thermo-electric batter or batteries is higher than in the case of a conventional air-conditioning installation duringp periods of operation when the air for air-conditioning is heated, - the risks of icing are reduced in the circuit through which the ambient air passes during periods of operation when the air for air-conditioning is heated, - from the constructional point of view, it is possible to construct particularly compact installations and to give them a form which facilitate their mounting, - cooling of a part of the convertor means (high voltage convertor assembly particularly) is provided by clean air since it is air extracted from the accomodation unit to be airconditioned, - as to the space factor, it is possible to separate the convertor means into several assemblies while recovering the heat from each of these assemblies, - while cooling the air for air-conditioning, at least a part of the convertor means is cooled by the air which is extracted from the accomodation unit to be airconditioned and is therefor cooler than the ambient air and this air is directly discharged without passing through the thermo-electric batteries, - it is advantageous during heating of the air for air-conditioning to recover the heat from a part of the air extracted while thus ensuring heating of the ambient air.

WHAT WE CLAIM IS: 1. A PELTIER effect air-conditioning installation for heating and cooling at least one accomodation unit, particularly for railway vehicles, comprising at least one thermo-electric battery defining an ambient air circuit and an air circuit for the conditioning air (air for air-conditioning to be heated or cooled with respect to the ambient air); first fan means for causing the ambient air to flow; second fan means for

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. battery), - and, for distributing the air for airconditioning from the thermo-electric batteries 1, two distribution ducts 14 (one per battery), disposed laterally. As shown in Figures 11 and 12, the convertor means are formed by a low voltage convertor assembly Sa and two high voltage convertor assemblies 5b, connected in series from the electrical point of view. The low voltage convertor assembly 5a is disposed axially between the two thermoelectric batteries 1 and the first fan means 2 are disposed axially, preferably towards the end of the two batteries which faces towards the end of the considered half of the vehicle. Such being the case, this low voltage convertor assembly 5a is arranged so as to be bathed by the ambient air flow and to be located upstream of the thermo-electric battery 1 considered in relation to the flow direction of the ambient air when the installation is heating the air for the air-conditioning. The two high voltage convertor assemblies 5b are arranged so as to be bathed by a flow of air extracted from the accomodation unit 4 to be air-conditioned by a third fan means 30. This flow of air extracted from the accomodation unit 4 to be air-conditioned flows in a succession of ducts 32,33,34 and 35. This air extracted from the accomodation unit 4 to be air-conditioned is directed, after bathing the two high voltage convertor assemblies 5b, into ambient air circuit, upstream of the thermo-electric battery 1 considered in relation to the direction of flow of the ambient air when the installation is heating the air for air-conditioning. From the constructional point of view, it will be noticed that - the duct 32 connects an intake opening 36 emerging in the accomodation unit 4 to be air-conditioned to the third fan means 30, - the duct 33 connects the third fan means 30 to the first of the two first high voltage convertor assemblies 5b, - the duct 34 connects this high voltage convertor assembly 5b to the other high voltage convertor assembly 5b, - and the duct 35 connects this high voltage convertor assembly 5b to the central duct 11 into which said duct 35 emerges laterally. According to the illustrated embodiments of the invention, on the one hand, in Figures 9 and 10 and, on the other hand, in Figures 11 and 12, an inverter device 6 is provided between the convertor assembly 5a and the thermoelectric battery 1 for inverting the direction of the DC current in the thermo-elements when changing over from operation for heating the air for air-conditioning to operation to cooling the air for air-conditioning. The first fan means 2 are fitted with a switch device 7 for providing, either a high ambient air delivery rate in a given direction for operation for cooling the air for air-conditioning, or a high ambient air delivery rate in the opposite direction for operation for heating the air for air conditioning. Referring to Figures 9 to 12, arrows F1 and F2 show the flow of ambient air when heating the air for air-conditioning (Figures 1 and 3) and when cooling the air for air-conditioning (Figures 2 and 4) respectively. This air for air-conditioning flows in the direction indicated by arrows G. There is also shown by arrows H1 and H2 the direction of rotation of fan 2 when heating the air for air-conditioning (Figures 1 and 3) and when cooling the air for air-conditioning (Figures 10 and 12) respectively. The supply polarity for the thermo-electric battery 1 is indicated at terminals A and B of this battery. This polarity is positive for terminal A and negative for terminal B when heating the air for air-conditioning (Figures 9 and 11), and negative for terminal A and positive for terminal B when cooling the air for air-conditioning (Figures 10 and 11). Finally, there is provided an air-conditioning installation which presents a certain number of advantages, of which the following may be mentioned: - it is not necessary to provide special means for cooling the convertor means - the yield of the thermo-electric batter or batteries is higher than in the case of a conventional air-conditioning installation duringp periods of operation when the air for air-conditioning is heated, - the risks of icing are reduced in the circuit through which the ambient air passes during periods of operation when the air for air-conditioning is heated, - from the constructional point of view, it is possible to construct particularly compact installations and to give them a form which facilitate their mounting, - cooling of a part of the convertor means (high voltage convertor assembly particularly) is provided by clean air since it is air extracted from the accomodation unit to be airconditioned, - as to the space factor, it is possible to separate the convertor means into several assemblies while recovering the heat from each of these assemblies, - while cooling the air for air-conditioning, at least a part of the convertor means is cooled by the air which is extracted from the accomodation unit to be airconditioned and is therefor cooler than the ambient air and this air is directly discharged without passing through the thermo-electric batteries, - it is advantageous during heating of the air for air-conditioning to recover the heat from a part of the air extracted while thus ensuring heating of the ambient air. WHAT WE CLAIM IS:

1. A PELTIER effect air-conditioning installation for heating and cooling at least one accomodation unit, particularly for railway vehicles, comprising at least one thermo-electric battery defining an ambient air circuit and an air circuit for the conditioning air (air for air-conditioning to be heated or cooled with respect to the ambient air); first fan means for causing the ambient air to flow; second fan means for

causing the conditioning air to flow towards its user station (accomodation unit to be airconditioned) and convertor means for the low voltage DC electrical supply of the thermoelectric battery, these convertor means being themselves supplied with electric current; at least part of said convertor means being arranged so as to be bathed by the flow of ambeint air, characterised by the fact that it is arranged so that, on the one hand, these convertor means are located upstream of the thermo-electric battery in relation to the direction of flow of the ambient air when the installation is heating the air for air-conditioning and, on the other hand, that these convertor means are located downstream of the thermo-electric battery in relation to the direction of flow of the ambient air when the installation is cooling the air for air-conditioning.

2. An air-conditioning installation according to Claim 1, characterised by the fact that the first fan means are operable for causing the ambient air to flow in either of two opposite directions as required.

3. An air-conditioning installation according to Claim 2, characterised by the fact that the first fan means are arranged for generating a delivery rate, during operation for cooling the air for air-conditioning, higher (of the order of three to seven times) than the delivery rate during operation for heating the air for airconditioning.

4. An air-conditioning installation according to Claim 3, characterised by the fact that first fan means are formed by at least one axial flow fan driven by a motor able to rotate it, either at high speed, in the suction direction (fan providing the high delivery rate during operation for cooling the air for air-conditioning), or at low speed, in the discharge direction (fan providing the low delivery rate during operation for heating the air for air-conditioning).

5. An air-conditioning installation according to any one of Claims 1 to 4, characterised by the fact that the second fan means are formed by at least one fan disposed at the outlet of the thermoelectric battery.

6. An air-conditioning installation according to any one of Claims 1 to 5, characterised by the fact that a recovery duct is provided between the accomodation unit to be air-conditioned and as duct for supplying air for airconditioning to the thermo-electric battery.

7. As air-conditioning installation according to any one of Claims 1 to 6, for air-condtioning a railway vehicle, characterised by the fact that it comprises several thermo-electric batteries disposed on each side of the central longitudinal axis of the vehicle, to convertor means and the first fan means being disposed axially.

8. An air-conditioning installation according to Claim 7, characterised by the fact that it comprises thermo-electric batteries disposed in pairs as an extension of each other and supplied with air for air-conditioning through their ends which face each other.

9. An air-conditioning installation according to any one of Claims 1 to 8, characterised by the fact that the convertor means are disposed between the thermo-electric batteries and the first fan means.

10. An air-conditioning installation according to any one of Claims 1 to 8, characterised by the fact that the first fan means are disposed between the thermo-electric battery and the convertor means.

11. An air-conditioning installation according to Claim 6, characterised by the fact that the recovery duct comprises two branches each provided with a valve for directing a part of the air taken from the accomodation unit to be air-conditioned into the ambient air-flow.

12. An air-conditioning installation according to any one of Claims 1 to 4, characterised by the fact that the second fan means are formed by at least one fan disposed at the inlet of the thermo-electric battery.

13. An air-conditioning installation according to Claim 7, characterised by the fact that it comprises several pairs of thermo-electric batteries, the batteries of the same pair being disposed as an extension of each other.

14. An air-conditioning installation according to Claims 12 and 13, characterised by the fact that the second fan means are formed by at least one fan having two opposed outlets disposed respectively facing the two ends of the thermo-electric batteries of the same pair which face each other.

15. An air-conditioning installation according to any one of Claims 1 to 14, characterised by the fact that the convertor means are formed by two assemblies disposed one on each side of the first fan means.

16. An air-conditioning installation according to Claim 15, characterised by the fact that the two constituent assemblies of the convertor means house, the one, the high voltage part and, the other, the low voltage part, and by the fact that the high voltage assembly is located on the outside in relation to the first fan means and the low voltage assembly on the inside in relation to the fan means.

17. An air-conditioning installation according to any one of Claims 1 to 16, in which the convertor means are formed by at least two separate convertor assemblies, characterised by the fact that one of these convertor assemblies is arranged so as to be bathed by the ambient air flow and to be located upstream of the thermoelectric battery in relation to the flow direction of the ambient air when the installation is heating the air for air-conditioning and by the fact that the other convertor assembly is arranged so as to be bathed by a flow of air extracted from the accomodation unit to be air-conditioned through third fan means.

18. An air-conditioning installation according to Claim 17, characterised by the fact that the air extracted from the accomodation unit to be air-conditioned is directed, after bathing one of the two convertor assemblies, into the ambient air circuit, upstream of the thermoelectric battery in relation to the flow direction of the ambient air when the installation is heating the air for air-conditioning.

19. An air-conditioning installation according to Claim 17 or 18, for a railway vehicle and in which the convertor means are formed by a low voltage convertor assembly and a high voltage convertor assembly, characterised by the fact that the low voltage convertor assembly is arranged so as to be bathed by the ambient air flow and by the fact that the high voltage convertor assembly is arranged so as to be bathed by the flow of air extracted from the accomodation unit to be air-conditioned.

20. An air-conditioning installation according to Claim 19, characterised by the fact that it comprises two high voltage convertor assemblies arranged in series in the flow of air extracted from the accomodation unit to be airconditioned.

21. An air-conditioning installation substantially as described hereinbefore with reference to any one of the figures of the accompanying drawings.