WO2005012805A1

WO2005012805A1 - Improvements in air conditioning systems

Info

Publication number: WO2005012805A1
Application number: PCT/AU2004/001016
Authority: WO
Inventors: J. Rosa; L. Bennet; D. Chapman; S. Fragepane; V. Tran
Original assignee: Air International Pty Ltd
Priority date: 2003-07-30
Filing date: 2004-07-30
Publication date: 2005-02-10
Also published as: AU2003904018A0

Abstract

The invention generally provides an apparatus for: (a) directing the flow of; and (b) presenting an air flow to a heat exchanger element in an air conditioning system, the apparatus comprising; (i) a housing element, the housing element having an inlet portion and a body portion, the housing element being adapted generally in use, to abut against or to be located in proximity to the heat exchanger element in the air conditioning system;and (ii) one or more flow direction means located on an internal face or wall of the housing element, to direct the flow of air, and so as to present that flow of air to the heat exchanger element, in use of the apparatus.

Description

IMPROVEMENTS IN AIR CONDITIONING SYSTEI

Field of the invention

This invention relates to improvements in air conditioning systems. It has particular, although not exclusive application to air conditioning systems used in vehicles, such as automobiles. Although the invention has broad application to air conditioning systems generally, it will be described in the section of this specification titled 'Background to the Invention' with specific reference to the automobile air conditioning system application to which it is particularly suited.

Background to the Invention Air conditioning systems have been used in motor vehicles for many years.

Although the use of air conditioning systems in motor vehicles has improved driver and passenger comfort considerably, the currently used air conditioning systems in motor vehicles suffer from a number of disadvantages. First, the current configuration of many automobile air conditioning systems comprises a circuit which includes (amongst other things) the following features:

• a refrigerant circuit to provide cold refrigerant to the evaporator;

• a 'blower' element (ie: an apparatus to induce a flow of air in the system, to be cooled or heated, as required);

• an evaporator, to remove moisture and cool air flowing through the system;

• one or more heat exchanger elements (to cool and/or heat the flow of air); and

• one or more outlets, so as to present the cooled or heated air to the passenger compartment of the vehicle. In such systems, it is important to optimise the presentation of air onto the heat exchangers in order to obtain sufficient heat exchange capacity and - so far as practicable - uniformity of air flowing through the system. This is because poor airflow presentation can lead to the system being unduly large and produce excessive outlet temperature variations (in operation of the air conditioning system) within the passenger compartment. In this context, what often happens in a conventional vehicle air conditioning system is that an air flow induced by the blower is presented to the heat exchanger in an undirected fashion, with the result that most of the flow of air travels through a relatively small area of the face of the inlet to the heat exchanger. This unharnessed flow of air therefore finds the path of least flow resistance through the heat exchanger. This usually means that the air flows in a 'stream' at relatively high velocity, and thus interacts with a relatively restricted area of the heat exchanger. In terms of the efficiency of heat exchange, for the following reasons, this state of affairs is less than optimal.

First, in order to optimise the cooling process, the longer the time during which a given volume of air is in contact with surfaces within the heat exchanger, the greater will be the extent of heat exchange to the refrigerant, and thus, the greater the degree of cooling achieved. Conversely, the higher the velocity at which the air travels through the heat exchanger, the less time there will be for heat exchange for a given volume of air flowing through the system. Where the air travels in a relatively high velocity 'stream', this therefore leads to less than optimal cooling. Where a volume of air is allowed to follow the path of least resistance, it tends to do so in a 'stream' which has a relatively restricted cross sectional area. This normally means that the volume of air will travel at a relatively higher velocity, than if it was dispersed so as to have a greater cross sectional area. Where the cross sectional area of the volume of flowing air is relatively greater, the mean velocity of the flowing air will be reduced. If this can be achieved, it results in the air being in contact for a longer period of time as it flows through the heat exchanger.

Attempts at achieving an appropriate heat exchange capacity in any such system have conventionally relied predominantly upon the heat exchange rating of the evaporator. Generally, the blower induces an air flow, which is then presented via a conduit, to an evaporator, where heat exchange occurs between the air and the cold refrigerant thus cooling and dehumidifying the air presented to it. The cooled and dehumidified air is then presented to a chamber that selectively diverts all or part of the airflow through a heat exchanger, which heats the diverted air, so that it may be re- combined with the undiverted air and directed through the remainder of the air conditioning circuit, and ultimately through to the passenger area of the vehicle, so as to create the desired climatic environment within that passenger compartment.

As explained earlier, the efficiency of the heating/cooling achieved in such a system also depends largely however, on the efficiency of the air to refrigerant heat exchange process. The greater the uniformity of air flow that is presented to the evaporator, the greater the efficiency of the entire system will be. As explained earlier, generally, the efficiency of the air to refrigerant heat exchange process has been driven by increasing the heat exchange capacity rating of the evaporator unit, with the attendant disadvantage of increasing the size and cost of the system, that this entails. Another disadvantage of concentrating on the capacity rating of the evaporator unit is that generally, larger sized evaporator units are required in order to achieve sufficient cooling capacity from the air conditioning unit. This creates a problem, given that the entire vehicle air conditioning system must be housed within a relatively confined space within an automobile.

Little attention has been given to date however, on improving the overall efficiency of an automobile air conditioning system, by focusing on the efficiency of the air to refrigerant heat exchange process, and the way in which that might be improved.

The present invention therefore aims principally to address this deficiency.

General disclosure of the Invention

The invention generally provides an apparatus for:

(a) directing the flow of; and (b) presenting an air flow to a heat exchanger element in an air conditioning system, the apparatus comprising; (i) a housing element, the housing element having an inlet portion and a body portion, the housing element being adapted generally in use, to abut against or to be located in proximity to the heat exchanger element in the air conditioning system; and (ii) one or more flow direction means located on an internal face or wall of the housing element, to direct the flow of air, and so as to present that flow of air to the heat exchanger element, in use of the apparatus.

Preferably, the air conditioning system is an air conditioning system for use in a vehicle. In this specification, wherever the word 'vehicle' is used, it is to be understood to mean:

• an automobile or motor vehicle;

• an aircraft; or

• a water-borne vessel, such as a boat or ship. In a preferred embodiment of the invention, the housing element takes the form of. a removably securable structure. In a preferred embodiment, the housing element takes the form of a structure which has an internal wall or face that is disposed at an angle relative to a notional plane defined by an inlet portion of an evaporation element in the air conditioning system. In this embodiment of the invention, a flow of air induced from the blower unit is presented to the wall or face of the housing element, so that it is deflected angularly towards the inlet portion of the evaporation element.

The wall or face of the housing element which receives the incoming flow of air from the blower unit also comprises one or more flow direction means, so as to direct the flow of air and present it to the inlet portion of the heat exchanger element. In a preferred form of the invention, the flow direction means located on the face or wall of the housing element take the form of one or more ribs or vanes that extend in a generally horizontal orientation, across at least a portion of the wall or face. It is particularly preferred that there are at least two flow direction means located on the wall or face of the housing element, and that those flow direction means are spaced apart in generally parallel fashion to one another. In a particularly preferred embodiment of the invention, there are at least four flow direction means located on the wall or face of the housing element, and they are located in spaced relationship to one another, and generally, they are parallel to one another. This arrangement prevents the air entering the housing from moving upwards in an unrestricted fashion, and results in a greater body of air being presented to the inlet portion of the heat exchanger element. Accordingly, a more uniform cross-sectional area of air flow is able to be presented to the heat exchanger element, thereby increasing the efficiency of the heat exchange process, and the subsequent down-stream efficiency of operation of the air conditioning system as a whole. In addition, this arrangement allows more generally for improved uniformity of the air flows throughout of the air conditioning system as a whole.

The invention also generally provides a method of:

(a) directing the flow of air; and

(b) presenting an air flow to a heat exchanger element in an air conditioning system, the method comprising the steps of: (i) providing the system with a housing element, the housing element having an inlet portion and a body portion, in which the housing element is adapted generally to abut against, or to be located in proximity to a heat exchanger element in the air conditioning system; and (ii) using one or more flow direction means located on an internal face or wall of the heat exchanger element, so as to direct the flow of air and to present it to an inlet portion of a heat exchanger element included within the system. Detailed description of preferred embodiments of the invention

Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawing/drawings, in which:

Referring now to the drawings, Fig 1 generally depicts a housing element (generally denoted 1 ) for use in an air conditioning system for an automobile, in accordance with the present invention. As will be seen from Figs 1 to 6 of the accompanying drawings, the housing element 1 comprises a wall or face (generally denoted 3) which has an inner face (denoted 3a) and an outer face (denoted 3b). As shown in Fig 1 , housing element 1 also comprises an end plate 5.

Fig 1 also shows that housing element 1 comprises a number of flow direction means (in the form of 'ribs' or Vanes') each denoted 7 in the accompanying drawings. In the illustrated embodiment, the flow direction means take the form of a series of generally triangular ribs or vanes which extend horizontally along the length of housing element 1 , in generally spaced apart parallel fashion. As will be particularly evident from Fig 5, the housing element has a generally triangular longitudinal profile. In an air conditioning system constructed in accordance with the invention, when a flow of air is induced by a blower unit in the system, it is introduced by a conduit means (not shown) via an inlet portion (denoted 9) and flows into the housing element in the direction of the arrow F shown in Fig 5. There, the flow of air encounters the inner face 3a of the housing element, and is deflected generally in the direction of the arrow G shown in Fig 5, so as to be presented to the inlet portion of a heat exchanger/ evaporation unit (not shown in Fig 5). The inlet portion of the evaporation until would - in use - generally be placed in abutment to the housing element 1 , in a direction that would be generally parallel to the direction of the arrow F shown in Fig 5. Accordingly, it will be seen that the wall or face 3 of the housing element 1 is at an angle relative to a notional plane defined by the inlet portion of the evaporation unit.

Air entering the housing element 1 in this way therefore encounters a series of horizontal barriers (in the form of the vanes or ribs 7), which prevent the air from flowing upwardly within the housing element, as would otherwise be its normal tendency. In this way, a greater cross-sectional flow of air is presented to the inlet portion of the evaporation unit, than otherwise would be the case, thereby increasing the operational efficiency of the evaporation process.

As will be evident from Figs 1 to 6, in the illustrated embodiment, the housing element 1 takes the form of an accessory structure, which - in the illustrated embodiment - can be secured into the air conditioning system, by appropriate securement means. In the illustrated embodiment of the invention shown in the accompanying drawings, the housing element 1 could be placed into securement in the system via the use of the tabs 13, each of which has a bore 15, through which a screw or pin could be threaded in order to secure the housing element 1 into place. In the illustrated embodiment, the housing element 1 could be made from plastics, metal or any other suitable material, in accordance with manufacturing techniques of a kind which would be well known to ordinary persons of skill in the art.

Fig 7 depicts a partial air conditioning system for a motor vehicle, the system shown including a blower unit (denoted 17), a conduit (19) connecting between the blower unit and the housing element 1 of the present invention, and the housing element 1 being connected to an evaporation unit 21. A similar system is also depicted in Fig 8, where a blower unit (17) is shown as being connected via a conduit 19 through to a housing element 1 , also constructed in accordance with the invention. In the embodiment shown in Fig 8 however, the partial system also

includes downstream elements of the system, such as vents for directing the flow of air either heated or cooled by heat exchangers in the system, and ultimately emitted via outlets 23 to the windscreen, or outlets 25 to the vehicle dashboard. The entire system would be mounted within a motor vehicle or other vehicle (as generally defined earlier in this specification), in accordance with techniques which would be well understood by ordinary persons of skill in the art.

An air conditioning system for a vehicle constructed in accordance with the present invention could feature the use of one or more than one heat exchanger. Such heat exchangers could take the form of:

• cooling elements; • heating elements; or

• a combination of heating and cooling elements,

as desired in any particular application. Heat exchangers for use in the apparatus and method of the invention could be integrally formed with an evaporator element, or separate to the evaporator element. The selection and use of heat exchangers in air conditioning systems constructed in accordance with the present invention would vary from case to case, as desired. Ordinary persons of skill in the art will readily understand that the invention is by no means limited to the particular constructional details of the embodiments disclosed in this specification, and that the method and apparatus aspects of the invention could take many forms, all such forms being included within the spirit and scope of the present invention.

It is to be understood that wherever used in this specification (including both the description and the claims), forms of the word 'comprise' are equivalent in meaning to the corresponding forms of the word 'include', and are thus not to be taken as excluding or implying the exclusion of a feature or integer. It will be also understood that the invention disclosed in this specification extends to all combinations of two or more of the individual features mentioned or evident from or implicit in the text of this specification or the accompanying drawings. All such different combinations constitute various alternative aspects of the invention.

DATED: 30 July 2004

AIR INTERNATIONAL PTY LTD

By its Registered Patent Attorneys MINTER ELLISON PATENT ATTORNEYS

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An apparatus for:

(a) directing the flow of; and

(b) presenting an air flow to a heat exchanger element in an air conditioning system, the apparatus comprising:

(i) a housing element, the housing element having an inlet portion and a body portion, the housing element being adapted generally in use, to abut against or to be located in proximity to the heat exchanger element in the air conditioning system; and

(ii) one or more flow direction means located on an internal face or wall of the housing element, to direct the flow of air, and so as to present that flow of air to the heat exchanger element, in use of the apparatus.

2. An apparatus as claimed in claim 1 , in which the apparatus is an air conditioning system.

3. An apparatus as claimed in claim 1 or claim 2, in which the apparatus is for use in a vehicle.

4. An apparatus as claimed in claim 3, in which the vehicle takes the form of: (a) an automobile or motor vehicle; (b) an aircraft; or

(c) a water-borne vessel.

5. An apparatus as claimed in any of the preceding claims, in which the housing element takes the form of a removably securable structure.

6. An apparatus as claimed in claim 5, in which the housing element takes the form of a structure which has an internal wall or face that is disposed at an angle relative to a notional plane defined by an inlet portion of a heat exchanger element in the apparatus.

7. An apparatus as claimed in claim 6, in which in use of the apparatus, a flow of air is induced from the blower unit and is presented to the wall or face of the housing element, so that it is deflected at an angle relative to a internal wall or face towards the inlet portion of the heat exchanger element.

8. An apparatus as claimed in claim 7, in which the wall or face of the housing element which is presented with the flow of air induced from the blower unit also comprises one or more flow direction means, so as to direct the flow of air and present it to the inlet portion of the heat exchanger element.

9. An apparatus as claimed in claim 8, in which the flow direction means comprise one or more ribs or vanes.

10. An apparatus as claimed in claim 9, in which the one or more ribs or vanes located on the face or wall of the housing element extend in a generally horizontal orientation, across at least a portion of the wall or face.

11. An apparatus as claimed in claim 10, in which the wall or face of the housing element which receives the incoming flow .of air from the blower unit comprises at least two flow direction means, which are spaced apart in a generally parallel fashion to one another.

12. An apparatus as claimed in claim 11 , in which the wall or face of the housing element which receives the incoming flow of air from the blower unit comprises at least four flow direction means, which are located in spaced apart in a generally parallel fashion to one another.

13. A method of:

(a) directing the flow of air; and

(b) presenting an air flow to a heat exchanger element in an air conditioning system,

the method comprising the steps of:

(i) providing the system with a housing element, the housing element having an inlet portion and a body portion, in which the housing element is adapted generally to abut against, or to be located in proximity to a heat exchanger element in the air conditioning system; and (ii) using one or more flow direction means located on an internal face or wall of the heat exchanger element, so as to direct the flow of air and to present it to an inlet portion of a heat exchanger element included within the airconditioning system.

14. An apparatus as claimed in any one of claims 1 to 12, substantially as described in this specification and with reference to the accompanying drawings and the examples of the invention given in the description.

15. A method as claimed in claim 13, substantially as described in this specification and with reference to the accompanying drawings and the examples of the invention given in the description.