AU2014208323B2

AU2014208323B2 - Air-conditioning system with vent mode

Info

Publication number: AU2014208323B2
Application number: AU2014208323A
Authority: AU
Inventors: Walter Kimble
Original assignee: AIRSTREAM COMPONENTS Pty Ltd
Current assignee: AIRSTREAM COMPONENTS Pty Ltd
Priority date: 2013-11-25
Filing date: 2014-08-05
Publication date: 2018-09-27
Anticipated expiration: 2034-08-05
Also published as: AU2014208323A1

Abstract

5 Abstract An air-conditioning system 10 with a vent mode for cooling a building 16, the air-conditioning system 10 comprising a ducting system 12 provided in a roof 10 space 14 of the building 16 for transporting cool air to selected rooms in the building 16. The system 10 also comprises a fan coil unit 18 mounted in the roof space 14 and operatively connected to the ducting system 12 for blowing cool air through the ducting system 12, as well as a return air grill 20 for allowing air from within the building 16 to be recirculated to the fan coil unit 15 18. The air-conditioning system 10 also comprises an air vent 22 provided in the roof of the building 16 for allowing air from outdoors to be drawn into the building 16. A first damper 24 operatively connected to the air vent 22 and to the ducting system 12, controls the flow of air from outdoors through the air vent 22 and into the ducting system 12 whereby, in use when operated in the 20 vent mode, the air-conditioning system 10 can draw-in air from outdoors and transport it through the ducting system 12 to selected rooms in the building. Drawing to accompany Abstract: Figure 2 goto

Description

COMPLETE SPECIFICATION

Invention title:

“AIR-CONDITIONING SYSTEM WITH VENT MODE”

Applicant:

AIRSTREAM COMPONENTS PTY LTD

Associated Provisional Application No.: 2013904568

The following statement is a full description of the invention, including the best method of performing it known to me:

2014208323 15 Aug 2018 “AIR-CONDITIONING SYSTEM WITH VENT MODE”

Field of the Invention

The present invention relates to an air-conditioning system with the capacity to draw-in fresh air from outside and relates particularly, though not exclusively, to such a system for domestic dwellings.

Background to the Invention

There are basically two types of ducted air-conditioning systems employed in buildings in warmer climes: those that rely on evaporative cooling and those that rely on refrigerative cooling. Evaporative cooling systems draw-in air from outside the building using a large roof-mounted fan unit. As the air passes through large water-saturated pads provided in connection with the fan unit, the temperature of the outside air can be significantly lowered due to the phase change of liquid water to water vapour (evaporation). Although evaporative cooling uses much less energy than refrigeration, it only works well in relatively dry climates. The greater the difference between the wetbulb temperature, (which takes both temperature and humidity into account), and the actual air temperature (dry-bulb temperature), the greater the evaporative cooling effect. When the wet- and dry-bulb temperatures are the same, no net evaporation of water in air occurs, and hence there is no cooling effect.

Most refrigerative cooling systems rely on the vapour-compression cycle for their operation, and employ a refrigerant which circulates through a compressor, a condenser coil, an expansion valve and an evaporator coil. The compressor causes pressure changes and pumps the refrigerant around the system. When the refrigerant changes phase from liquid to vapour in the evaporator coil, it draws heat from the environment into the refrigerant to produce the cooling effect. At the opposite end of the cycle, the refrigerant vapour is compressed and forced through the condenser coil where it is

2014208323 15 Aug 2018 condensed into a liquid, thus releasing the heat previously absorbed. If the refrigerant is forced to circulate in the opposite direction, as in a reverse cycle air-conditioner, the same system can also be used for heating.

In large commercial buildings, a complete system of heating, ventilation and air-conditioning is referred to by the acronym HVAC. However most domestic air-conditioning systems do not combine all three elements of a HVAC system. Domestic evaporative air-conditioning systems can be operated in both cooling and ventilation modes, as they always draw outside air into the building. This is why it is necessary to have a window or door open when operating an evaporative air-conditioning system, as the air drawn in from outside must have somewhere to go. By contrast, domestic refrigerative airconditioning systems require that all external windows and doors be kept closed as they rely on the air within the building being recirculated in order to cool the air.

However there are times, especially at night, when the outside air may be cooler that inside a house and it may therefore be desirable to draw in the cooler outside air to help cool the building. It may also be desirable to ventilate the house, as the recirculating air within can become quite ‘stale’. This can be done simply by opening the external windows and doors.

However, if there is no breeze, this has little effect.

The present invention was developed with a view to providing an airconditioning system with vent mode that has the capacity to draw-in fresh air from outside the building, using the existing fan coil unit and ducting system of a conventional refrigerative air-conditioning system. The invention also provides an air flow control unit that can be retrofit to an existing airconditioning system to provide a ventilation mode. It will be understood that the airflow control unit can also be used in conjunction with reverse cycle airconditioning systems.

References to prior art in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.

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Summary of the Invention

According to a first aspect of the present invention there is provided an air flow control unit for a reverse cycle air-conditioning system with a vent mode for cooling and/or heating a building, the air-conditioning system being of the kind having a ducting system provided in a roof space of the building for transporting air to selected rooms in the building, and a fan coil unit mounted in the roof space and operatively connected to the ducting system for blowing cool or warm air through the ducting system, the air flow control unit comprising:

an enclosure having a first air inlet adapted to be connected to an air vent provided in the roof of the building for allowing air from outdoors to be drawn into the building; an air outlet adapted to be connected to the fan coil unit; a first damper provided in connection with the first air inlet, the first damper having a closed position in which air from outdoors cannot be drawn into the enclosure and an open position in which air from outdoors can be drawn into the enclosure via the air inlet; a second air inlet for allowing recirculated air to flow into the enclosure via a return air grill formed integral to the enclosure for allowing air from within the building to pass through the enclosure and to be recirculated via the air outlet to the fan coil unit; a second damper for controlling the flow of recirculated air into the enclosure via the second air inlet, the second damper having a closed position in which recirculated air from within the building cannot be drawn into the enclosure and an open position in which recirculated air can be drawn into the enclosure whereby, in use, when the air-conditioning system is operated in the vent mode the second damper is closed to prevent recirculated air from within the building from being drawn into the enclosure and the first damper is opened to allow air from outdoors to be drawn into the enclosure and transported through the ducting system to selected rooms in the building; and, wherein the return air grill is adapted to be mounted in a ceiling of the building and the enclosure has external dimensions the same as or smaller than that of the return air grill so as to permit the air flow control unit to be installed in the roof space of the

2014208323 15 Aug 2018 building via an opening provided in the ceiling sized to receive the return air grill.

Preferably the air flow control unit further comprises a fresh air filter for filtering the air from outdoors drawn into the enclosure. Preferably the fresh air filter is removably mounted within the enclosure between the first air inlet and air outlet. Advantageously the fresh air filter can be accessed via an access aperture provided behind the return air grill.

Preferably the air grill has a plenum space behind it, which is connected to the return air duct and is bounded by a bottom wall of the enclosure, and wherein the access aperture is provided in the bottom wall of the enclosure and access to the fresh air filter is via this plenum space.

Preferably wherein an elongate, hinged panel is provided in the bottom wall of the enclosure, to cover the access aperture whereby, in use, if it desired to replace or clean the fresh air filter, the ceiling mounted return air grill is opened, and then the hinged panel is opened, allowing the fresh air filter to be pulled downwards and removed.

Advantageously the first air inlet of the enclosure is adapted to be connected to the air vent via a duct having a first spigot connector provided in connection therewith, and the air outlet is likewise adapted to the connected to the fan coil unit via a duct having a second spigot connector provided in connection therewith whereby, in use, the spigot connectors facilitate installation of the air flow control unit via the opening provided in the ceiling for the return air grill. Preferably the first spigot connector has the first damper provided integral therewith.

Preferably the air flow control unit is provided with an electronic controller for controlling the operation of the first and second dampers. Preferably the electronic controller comprises control logic which ensures that whenever the first damper is open the second damper is closed, and vice versa.

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According to another aspect of the invention there is provided a reverse cycle air-conditioning system with a vent mode for cooling a building, the airconditioning system comprising:

a ducting system provided in a roof space of the building for transporting cool 5 air to selected rooms in the building;

a fan coil unit mounted in the roof space and operatively connected to the ducting system for blowing cool air through the ducting system;

a return air grill operatively connected to the ducting system for allowing air from within the building to be recirculated to the fan coil unit;

an air vent provided in the roof of the building for allowing air from outdoors to be drawn into the building; and, an air flow control unit as described above.

Throughout the specification, unless the context requires otherwise, the word 15 “comprise” or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word “preferably” or variations such as “preferred”, will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention.

Brief Description of the Drawings

The nature of the invention will be better understood from the following detailed description of several specific embodiments of the air-conditioning system and air flow control unit, given by way of example only, with reference to the accompanying drawings, in which:

Figure 1 illustrates a preferred embodiment of an air-conditioning system with a vent mode in accordance with the present invention operating in recycle mode;

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Figure 2 illustrates the air-conditioning system of Figure 1 operating in vent mode; and,

Figure 3 is a cross-section view of a preferred embodiment of an air flow control unit in accordance with the present invention.

Detailed Description of Preferred Embodiments

A preferred embodiment of an air-conditioning system 10 with a vent mode for cooling a building 16 in accordance with the invention, as illustrated in Figures 1 and 2, comprises a ducting system 12 provided in a roof space 14 of the building for transporting cool air to selected rooms in the building 16. The building is typically a domestic building, such as a house 16, but may also be a commercial building such as an office or factory unit. A fan coil unit 18 is also mounted in the roof space 14 of the building 16 and is operatively connected to the ducting system 12 for blowing cool air through the ducting system. The air-conditioning system 10 may be a reverse-cycle airconditioning system capable of both cooling and heating the air within the building 16. In that case, the ducted air-conditioning system 10 would typically be a split system and would also have an externally located inverter (not shown), which operates in tandem with the fan coil unit 18. The fan coil unit 18 of the air-conditioning system 10 operates like a normal fan coil unit in both refrigeration and heating modes.

A return air grill 20 is operatively connected to the ducting system 12 for allowing air from within the building 16 to be recirculated to the fan coil unit

18. The air-conditioning system 10 described thus far is substantially identical to a conventional refrigerative or reverse-cycle air-conditioning system.

In order to be able to operate the air-conditioning system 10 in a ventilation mode, an air vent 22 is provided in the roof of the building 16 for allowing air from outdoors to be drawn into the building. Air vent 22 is preferably provided with a roof-mounted cowl 26 to prevent the ingress of rain, birds, etc into the air vent 22. A first damper 24 is operatively connected to the air vent 22 for controlling the flow of air from outdoors through the air vent 22 and into the

2014208323 15 Aug 2018 ducting system 12. By opening the first damper 24, as shown in Figure 2, the fan coil unit 18 can used to draw outside air into the ducting system 12. In this way, when operated in the vent mode, the air-conditioning system 10 can draw-in air from outdoors and transport it through the ducting system 12 to selected rooms in the building 16 to provide ventilation.

Preferably the air-conditioning system 10 further comprises an air flow control unit 30, and the first damper 24 is provided in connection with the air flow control unit 30. Preferably the air flow control unit 30 comprises an enclosure 32 having a first air inlet 34 adapted to be connected to the air vent 22. The enclosure 32 is typically manufactured from duct board, which is polyurethane or phenolic board sandwiched between two thin layers of aluminium, and is preferably of rectangular construction, as shown in Figure

3. The enclosure 32 also has an air outlet 36 adapted to the connected to the fan coil unit 18.

Preferably the first damper 24 is provided in connection with the first air inlet 34. The first damper 24 has a closed position, (as shown in Figure 1), in which air from outdoors cannot be drawn into the enclosure 32 from the air vent 22, and an open position (as shown in Figure 2) in which air from outdoors can be drawn into the enclosure 32 via the first air inlet 34. In use, when the air-conditioning system 10 is operated in the vent mode, the first damper 24 is opened to allow air from outdoors to be drawn into the enclosure 32 and then transported through the ducting system 12 to selected rooms in the building 16.

Preferably the air flow control unit 30 further comprises a second air inlet 38 for allowing recirculated air to flow into the enclosure 32 via the return air grill 20 of the air-conditioning system 10. Preferably the air flow control unit 30 also comprises a second damper 40 for controlling the flow of recirculated air into the enclosure 32 via the second air inlet 38. In its closed position the second damper 40 prevents recirculated air from within the building to be drawn into the enclosure 32, whereas in its open position the recirculated air can be drawn into the enclosure 32. Preferably, when the air-conditioning

2014208323 15 Aug 2018 system 10 is operated in the vent mode, the second damper 40 is closed to prevent recirculated air from within the building from being drawn into the enclosure 32 and back into the fan coil unit 18. In vent mode, it is preferred that the warmer, stale air inside the building 16 be vented through opened windows and doors, while the cooler, fresh air from outside is drawn in via the air vent 22.

The air flow control unit 30 may be mounted in the roof space 14, with the second air inlet connected to a separately mounted return air grill 20 via a duct (not shown). However, advantageously, in the preferred embodiment the air flow control unit 30 has the return air grill 20 formed integral to the enclosure 32 wherein, in use, recirculated air passes through the air flow control unit 30 and returns via the air outlet 36 to the fan coil unit 18 of the air-conditioning system 10. Preferably the return air grill 20 is adapted to be mounted in a ceiling of the building 16 and the enclosure 32 is of a size that permits the air flow control unit to be installed in the roof space 14 of the building via an opening provided in the ceiling for the return air grill 20. This makes it particularly easy to retrofit the air flow control unit 30 to an existing installed air-conditioning system.

Preferably the air flow control unit 30 further comprises a fresh air filter 42 for filtering the air from outdoors drawn into the enclosure 32, As can be seen most clearly in Figure 3, the fresh air filter 42 is removably mounted within the enclosure 32 between the first air inlet 34 and air outlet 36. Preferably the fresh air filter 42 is located in close proximity to the air outlet 36.

Advantageously the fresh air filter 42 can be accessed via an access aperture 44 provided behind the return air grill 20. As with a conventional return air grill, the grill 20 has a plenum space 46 behind it, which is connected to the return air duct. However in this embodiment of the air flow control unit 30 the plenum space is bounded by the bottom wall of the duct board enclosure 32. Access to the fresh air filter 42 is via this plenum space

46. An elongate, hinged panel 48 is provided in the bottom wall of the enclosure 32, to cover the access aperture 44. If it desired to replace or clean

2014208323 15 Aug 2018 the fresh air filter 42, the ceiling mounted return air grill 20, (which is also hinge-mounted) is opened, and then the hinged panel 48 is opened, allowing the fresh air filter 42 to be pulled downwards, so that it slides out of its mounting grooves (not visible).

The primary purpose of the fresh air filter 42 is to filter out any insects or dust particles that may be borne in with the air from outdoors via the air vent 22. However by locating the fresh air filter in close proximity to the air outlet 36, it also serves as an additional filter for the recirculated return air. The return air grill 20 will normally have at least one return air filter 50 provided in connection therewith. This may be a single, double or triple layer filter. Advantageously, in the normal air-conditioning mode the recirculating return air will not only pass through the return air filter 50, but it will also pass through the fresh air filter 42, providing additional filtering for the recirculating air.

Advantageously the first air inlet 34 of the enclosure 32 is adapted to be connected to the air vent 22 via an outdoor air duct 52 having a first spigot connector 54 provided in connection therewith. The air outlet 36 is likewise adapted to the connected to the fan coil unit via a return air duct 56 having a second spigot connector 58 provided in connection therewith. Preferably the spigot connectors 54 and 58 are of the kind described in co-pending Australian Patent Application No 2013200598 filed on 4^th February 2013, the contents of which are incorporated herein by reference.

Advantageously, the spigot connectors 54 and 58 facilitate installation of the air flow control unit 30 via the opening provided in the ceiling for the return air grill. In particular, the enclosure 32 can be received through the opening in the ceiling for the return air grill 20, since its external dimensions are the same as or smaller than that of the return air grill 20. Once the enclosure 32 and its return air grill 20 are installed in the ceiling, it is a simple matter for the installer to insert the spigot connectors 54 and 58 in the first air inlet 34 and the air outlet 36 respectively (within the roof space 14). Preferably the first spigot connector 54 has the first damper 24 provided integral therewith.

2014208323 15 Aug 2018

Preferably the air flow control unit 30 is provided with an electronic controller for controlling the operation of the first and second dampers 24 and 40. Typically the electronic controller (not shown) for the air flow control unit will be provided integral to the electronic controller for the air-conditioning system

10. Preferably the electronic controller comprises control logic which ensures that whenever the first damper 24 is open the second damper 40 is closed, and vice versa. This will ensure that whenever the air-conditioning system 10 is in normal air-conditioning mode, it will not be able to draw air in from outside, but will only recirculate air within the building 16 via the return air grill

20. On the other hand, whenever the air-conditioning system 10 is in vent mode, it will only be able to draw air in from outside via the air vent 22, and will not be able to recirculate air within the building 16. In vent mode, the refrigeration system in the fan coil unit 18 will also be disabled, so that only the fan operates in vent mode.

If desired, the electronic controller for the air flow control unit 30 may also be provided with indoor and outdoor enthalpy or temperature sensors 60 and 62, as shown in Figures 1 and 2. A comparison of the sensing signals from the sensors 60 and 62 will allow the electronic controller to automatically determine whether to switch to vent mode, or to remain in air-conditioning mode. Alternatively, or in addition, the electronic controller may be provided with a simple manual control, which relies on the user to decide when it is appropriate to switch from air-conditioning to vent mode. Of course there will also be substantial power-savings in vent mode, as the refrigeration system of the air-conditioning system will not be in use.

The air flow control unit 30 of the preferred embodiment is particularly advantageous as it can be readily retrofitted to an existing refrigerative or reverse-cycle air-conditioning system. However it will be appreciated that the air flow control unit may take other forms, in addition to that described above, and may be provided independently of the return air grill.

2014208323 15 Aug 2018

Now that preferred embodiments of the air-conditioning system with vent mode and air flow control unit have been described in detail, it will be apparent that the described embodiments provide a number of advantages over the prior art, including the following:

(i) They provide a way of allowing a refrigerative or reverse-cycle airconditioning system to be operated in a vent mode, thereby providing greater versatility of operating modes.

(ii) They permit significant savings in power-consumption in vent mode, providing a more environmentally-friendly refrigerative or reverse-cycle air-conditioning system.

(iii) The air flow control unit can be readily retrofitted to an existing conventional air-conditioning system, enabling it to be modified to provide a ventilation mode.

(iv) The air flow control unit is easy installed as it can be inserted into the roof space through the opening provided in the ceiling for the return air grill.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, whilst the air flow control unit of the preferred embodiment is of rectangular construction, it may be of any suitable shape. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described.

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Claims

The Claims defining the Invention are as follows:

1. An air flow control unit for a reverse cycle air-conditioning system with a vent mode for cooling and/or heating a building, the air-conditioning system

5 being of the kind having a ducting system provided in a roof space of the building for transporting air to selected rooms in the building, and a fan coil unit mounted in the roof space and operatively connected to the ducting system for blowing cool or warm air through the ducting system, the air flow control unit comprising:

10 an enclosure having a first air inlet adapted to be connected to an air vent provided in the roof of the building for allowing air from outdoors to be drawn into the building; an air outlet adapted to be connected to the fan coil unit; a first damper provided in connection with the first air inlet, the first damper having a closed position in which air from outdoors cannot be drawn into the

15 enclosure and an open position in which air from outdoors can be drawn into the enclosure via the first air inlet; a second air inlet for allowing recirculated air to flow into the enclosure via a return air grill formed integral to the enclosure for allowing air from within the building to pass through the enclosure and to be recirculated via the air outlet to the fan coil unit; a

20 second damper for controlling the flow of recirculated air into the enclosure via the second air inlet, the second damper having a closed position in which recirculated air from within the building cannot be drawn into the enclosure and an open position in which recirculated air can be drawn into the enclosure whereby, in use, when the air-conditioning system is operated in

25 the vent mode the second damper is closed to prevent recirculated air from within the building from being drawn into the enclosure and the first damper is opened to allow air from outdoors to be drawn into the enclosure and transported through the ducting system to selected rooms in the building; and, wherein the return air grill is adapted to be mounted in a ceiling of the

30 building and the enclosure has external dimensions the same as or smaller than that of the return air grill so as to permit the air flow control unit to be

2014208323 15 Aug 2018 installed in the roof space of the building via an opening provided in the ceiling sized to receive the return air grill.
2. An air flow control unit as defined in claim 1, further comprising a fresh air filter for filtering the air from outdoors drawn into the enclosure.

5
3. An air flow control unit as defined in claim 2, wherein the fresh air filter is removably mounted within the enclosure between the first air inlet and air outlet.
4. An air flow control unit as defined in claim 3, wherein the fresh air filter can be accessed via an access aperture provided behind the return air grill.

10
5. An air flow control unit as defined in claim 4, wherein the air grill has a plenum space behind it, which is connected to the return air duct and is bounded by a bottom wall of the enclosure, and wherein the access aperture is provided in the bottom wall of the enclosure and access to the fresh air filter is via this plenum space.

15
6. An air flow control unit as defined in claim 5, wherein an elongate, hinged panel is provided in the bottom wall of the enclosure, to cover the access aperture whereby, in use, if it desired to replace or clean the fresh air filter, the ceiling mounted return air grill is opened, and then the hinged panel is opened, allowing the fresh air filter to be pulled downwards and removed.

20
7. An air flow control unit as defined in claim 1, wherein the first air inlet of the enclosure is adapted to be connected to the air vent via a duct having a first spigot connector provided in connection therewith, and the air outlet is likewise adapted to the connected to the fan coil unit via a duct having a second spigot connector provided in connection therewith whereby, in use,

25 the spigot connectors facilitate installation of the air flow control unit via an opening provided in the ceiling for a return air grill.
8. An air flow control unit as defined in claim 7, wherein the first spigot connector has the first damper provided integral therewith.

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9. An air flow control unit as defined in any one of claim 1 to 8, wherein the air flow control unit is provided with an electronic controller for controlling the operation of the first and second dampers.
10. An air flow control unit as defined in claim 9, wherein the electronic 5 controller comprises control logic which ensures that whenever the first damper is open the second damper is closed, and vice versa.
11. A reverse cycle air-conditioning system with a vent mode for cooling a building, the air-conditioning system comprising:

a ducting system provided in a roof space of the building for transporting cool 10 air to selected rooms in the building;

a fan coil unit mounted in the roof space and operatively connected to the ducting system for blowing cool air through the ducting system;

a return air grill operatively connected to the ducting system for allowing air from within the building to be recirculated to the fan coil unit;
15 an air vent provided in the roof of the building for allowing air from outdoors to be drawn into the building; and, . an air control unit as defined in anyone of claims 1 to 10.