FIELD OF THE INVENTION

[0001 ] The present invention relates to evaporative cooling systems. [0002] The present invention finds particular application in air conditioning. BACKGROUND TO THE INVENTION

[0003] Evaporative air conditioners are known for reasonably low energy consumption and affordability, but have relatively poor performance in humid environments. Evaporative air conditioners are also not reverse-cycle; they can only cool, not heat.

[0004] Traditional evaporative coolers are simple in construction and principle, incorporating a circulation fan, wetted pads and a pump mounted in a system 'box'. They do not use refrigerants like CFCs and HCFCs for the cooling process because they do not have a compressor or heat exchange coils; they simply rely on evaporation of water from the large surface area of the wetted pads to cool the air passing through the pads.

[0005] Evaporative coolers generally only consume about one quarter of the energy of a compressor/refrigerative air conditioner because electrical power is used only to operate the fan and water pump.

[0006] However, Legionnaires disease is a problem of these traditional evaporative systems, although generally only rarely in large cooling towers and virtually never in domestic systems. [0007] The simplest form of evaporative cooling described above is classed as 'Direct Evaporative Cooling' (DEC). DEC is simply air passing through wetted pads, with cooled air, higher in humidity, passing out of the pads. The main disadvantage of direct evaporative cooling is that the cooled air has raised humidity because of the evaporated fluid entrained therein.

[0008] An alternative evaporative cooling system developed by the present applicant is the subject of PCT International Application PCT/AU2012/000289 published as WO 2012/126052. Such an evaporative cooling system utilises a fan with nozzles on or immediately behind the trailing edges of the blades of the fan. A mist of liquid droplets is sprayed from the nozzles into and against the airflow created by the fan blades, using velocity differential to create high rates of evaporation.

[0009] Each of the aforementioned prior developed systems have limited capacity to cool air. It has been realised that the efficiency and effectiveness of an evaporative cooling system can be improved.

[0010] It is with such limitations in mind that the present invention has been developed.

[001 1 ] It is desirable for one or more forms of the present invention to provide a low energy, low cost and optimum performance evaporative cooling system via a spinning axial fan and separate but closely located spinning/rotating spray device.

SUMMARY OF THE INVENTION

[0012] With the aforementioned in mind, the present invention provides an evaporative cooling system including a rotary fan and a rotary device with at least one nozzle for delivering a spray of liquid droplets into an airflow created by the fan, the rotary device being spaced from the fan, and drive means configured to rotate the rotary device at a different rate/speed of rotation than that of the fan.

[0013] The rotary device may include a ring, annulus, disc, hoop or a second fan, or a combination of any two or more thereof.

[0014] The rotary device may include multiple said nozzles.

[0015] Preferably the rotary device is configured to be rotated in the same direction as the fan when in use.

[0016] Alternatively, the rotary device is configured to be rotated in an opposite direction to the fan when in use.

[0017] Preferably the rotary device and/or the fan may be configured to have their respective speed/rate of rotation varied.

[0018] More preferably, the rotary device may be configured to be rotated at a speed faster or slower than rotation of the fan.

[0019] Preferably, the rotary device is rotatably driven by gearing or by direct drive from a motor. Gearing may be connected to the fan such that rotation of the fan drives rotation of the rotary device. Such gearing may drive the rotary device to rotate faster than the fan, slower than the fan or at the same speed as the fan. The rotary device may be driven to rotate at a multiple times speed of the fan.

[0020] The evaporative cooling system may have a said rotary device provided upstream or downstream of the fan with respect to airflow created by the fan, or may have at least two such rotary devices with at least one provided upstream and at least one provided downstream. [0021 ] The fan may include a hub with multiple blades extending therefrom. The at least one nozzle of the rotary device may be provided downstream of an airflow created from the blades.

[0022] The rotary device may be coaxial with the fan. For example, the fan may include at least one axial fan and the rotary device may have an axis of rotation coaxial with the axis of the axial fan.

[0023] The at least one nozzle may be configured to spray liquid droplets forwards with respect to a direction of rotation of the rotary device.

[0024] Alternatively, the at least one nozzle may be configured to spray liquid droplets rearwards with respect to a direction of rotation of the rotary device.

[0025] The at least one nozzle may be configured to spray liquid droplets towards the fan or away from the fan.

[0026] The rotary device may be configured to spray liquid droplets forwards from at least one said nozzle and/or rearwards from at least one other said nozzle with respect to a direction of rotation of the rotary device.

[0027] Each said nozzle may be provided on a wing or winglet (or

combination thereof) of the rotary device. For example, the rotary device may include multiple wings or winglets augmenting and/or modifying airflow from the fan.

[0028] Each said nozzle may be provided on a support projecting from a hub, wing, winglet or airflow modifier (such as a hoop).

[0029] An inlet for supplying liquid into the rotary device may be on an opposite side of the rotary device to the drive means for the rotary device. [0030] Alternatively, an inlet for supplying liquid into the rotary device may be on a same side of the rotary device to the drive means for the rotary device, such that the liquid to the nozzles passes through the drive means.

[0031 ] It will be appreciated that one or more forms of the evaporative cooling system of the present invention may be used in, but not limited to, direct evaporative cooling (DEC) systems or indirect evaporative cooling (IEC) systems where liquid spray nozzles are separated from, and preferably independent of, the fan.

[0032] The evaporative cooling system described in published application WO 2012/126052 has the nozzles located as part of the fan, with the nozzles emitting spray at or near the trailing edge of the fan blades. However, the nozzles and blades rotate together linked to the same hub and same motor and spinning at the same RPM.

[0033] The present invention is significantly distinguished from the

evaporative system described in WO 2012/156052 by distinctly separating the fan and nozzle components and relative rotation thereof.

[0034] According to one or more embodiments of the present invention, the rotary device is able to spin at different RPM to the fan. For example, the fan could be spinning at 800 RPM while the rotary device with the at least one nozzle can be spinning at a different RPM, for example, 2000 RPM.

[0035] It will be understood that the evaporative cooling system described in WO 2012/156052 has an essential limitation in that as RPM increases, the air flow increases at a greater rate than the fluid flow rate increased through the nozzles. Therefore, there is a crossover point between two performance curves of different slopes (fluid flow from the nozzles vs airflow from the fan) and therefore an ideal ratio of fluid to airflow (where evaporation creates 100% relative humidity of the output air) can only be achieved at that optimum point, for any given ambient conditions.

[0036] Conversely, it is a distinct advantage of the present invention in having individual, separate RPM control between the fan and the fluid flow from the nozzle(s) whereby the output airflow (cooled air) can be maintained at 100% Relative Humidity (RH) if required through a wide range of ambient conditions.

[0037] Another key advantage of present invention is that the spray (e.g. as a mist of atomised droplets) can be ejected from the nozzle(s) of the system of one or more embodiments of the present invention at a much higher velocity than from the nozzles of the system described in WO 2012/156052.

[0038] Fans are designed to run at RPM that is not too high so as to maintain noise at reasonably low levels. Having the nozzles fixed behind the blades of the system described in WO 2012/156052 therefore restricts the velocity of the nozzles.

[0039] With one or more embodiments of the present invention, the nozzle(s) can be spun at much higher velocity because of the separation of the nozzle(s) from the fan, which results in improved evaporation rates.

[0040] Noise (and energy use) from a higher revving rotary device of the present invention can be much less than from the fan because the rotary device can be much more aerodynamic and exhibit lower drag than the fan.

[0041 ] A further advantage of the higher spin rate or RPM of the rotary device relative to the fan is that the higher pressure induced centrifugally not only increases fluid flow rate through the/each nozzle, but it also reduces the droplet size of the spray being emitted. Therefore, the resulting mist can be much finer in droplet size than from the system described in WO 2012/156052. The smaller droplet size results in a further improvement in evaporation efficiency and performance of the system, simply because the smaller the average droplet size of a mist, the faster the evaporation rate.

[0042] Traditional DEC and IEC evaporative systems require pumps to keep water circulating around and over the pads.

[0043] One or more forms of the present invention can use centrifugal pressure induced in the liquid at the nozzles from the spin rate of the rotary device, therefore pressurizing the nozzles without pumps being required.

[0044] In one or more embodiments, pressure from a pumped or gravity water supply to the rotary device may be provided in addition to the centrifugal pressure, further pressuring the liquid at the nozzles.

[0045] One or more forms of the present invention demonstrates an extremely important advantage; the rotary device with the nozzle(s) can be located in front of virtually any axial fan (in front meaning in the airflow from the fan - i.e.

downstream in terms of airflow from the fan).

[0046] The rotary device (preferably having its own drive and controls) may be provided as a retrofit or augmenting system for an output air side of an axial fan (preferably of similar diameter for efficiency).

[0047] With this in mind, a further aspect of the present invention provides an apparatus to convert an airflow fan to an evaporative cooling system or to augment an existing air-conditioning system having a fan, the apparatus including a rotary device with at least one nozzle for delivering a spray of liquid, a drive means configured to rotate the rotary device at a different rate/speed of rotation than the airflow fan the fan of the existing air-conditioning system, and a liquid supply means to provide liquid to the at least one nozzle. [0048] Preferably the at least one nozzle may be provided as close as possible to a trailing edge of at least one blade of the fan whilst still permitting separate rotation of the fan and the rotary device.

[0049] Having the nozzle(s) close to the trailing edge(s) of the blade(s) of the fan ensures mist ejection from the respective nozzle is in a region of maximum air velocity and turbulence created by the fan as the airflow shears off the blade(s).

[0050] However, it is to be appreciated that the rotary device and/or its respective nozzle(s) can be provided spaced further from the fan blade(s), such as when it is not physically possible (e.g. due to design/specification/location constraints) to get so close.

[0051 ] One or more conduits for the liquid to the nozzle(s) may be provided within or on a surface of, or a combination thereof, the supports for the nozzle(s), such as the hub and/or blades, winglets, wings spars, struts or other supports to the nozzle(s) as provided for a given application

[0052] Preferably, one or more supports for the nozzle(s), such as, for example, incorporating or forming the one or more conduits, may be configured to minimise or at least reduce air drag so as to have little effect on the air flow emanating from the fan, e.g. if low energy is the key factor. The lower the drag, the lower the power use of the rotary device and also the lower the noise.

[0053] Although spinning at relatively high RPM, the rotary device can use very low power because it can incorporate a low drag spinning disk, annulus or ring/hoop. The fan would be expected to generally use more power than the rotary device.

[0054] Alternatively, the one or more supports and/or conduits e.g. that support and/or lead to the nozzle(s), may be used to increase air flow from the fan, if desired. The one or more supports or conduits can be configured as foils (e.g. like fan blades, wings or winglets). The supports or conduits may take the form of additional blades to boost overall airflow through the evaporative cooling system.

[0055] Such foils (e.g. as booster style blades) may generally have a higher aspect ratio and may be rotated/spun faster than the blades of the fan. This would have the effect of lowering pressure downwind of the fan blades, boosting overall airflow through the evaporative cooling system.

[0056] The supports, such as the tabs, wings, winglets, foils or tubes (forming the conduits) that carry the liquid (e.g. in one or more conduits or forming the conduit(s)) from the rotary device to the nozzles can also be minimized in structure by incorporating a ring (preferably supporting or incorporating the nozzles) and minimal structural supports leading out to the ring. For example, the ring could include a number of said nozzles (e.g. 8-12) while only a few (e.g. 3-4) structural supports hold the ring to the hub, therefore minimizing air drag.

[0057] Preferably the structural supports may be foil shaped in cross section in a direction of rotation of the rotary device.

[0058] As a further option, the nozzles can point from the ring towards the airflow from the fan (e.g. against the fan airflow) rather than directly against the spin direction of the ring. This still maintains high relative velocities while reducing aerodynamic drag of the ring.

[0059] A control system can be provided to manage relative and total spin speeds of the fan and the rotary device. Efficiency and output of the evaporative cooling system can be managed by controlling the relative and total spin speeds. The control system may also be utilised to manage flow/pressure of the liquid to the nozzles. [0060] For example, if a higher volume/rate of cooled airflow is required from the evaporative cooling system, the fan RPM can be increased and the control system may increase fluid flow via the nozzles by a corresponding increase in spin rate of the rotary device until the fluid evaporation increases e.g. to 100% RH (i.e. Wet Bulb), if maximum temperature differential is required (for example, higher RPM can be used to increase centrifugal pressure at the nozzles and therefore increase fluid flow from the nozzles - which may also help to atomise the droplets even further than at the lower RPM).

[0061 ] Also, if ambient conditions of temperature and RH change, the control system may adjust the relative spin rates of the fan and the rotary device for optimum performance. By way of example, if Australian Standard AS2913 conditions (Dry Bulb 38.0 and Wet Bulb 21 .0 ^° C), are the ambient conditions being targeted, then the calculation procedure of the control system could be as follows:

1 . Determine a cooled airflow output requirement or cooled airflow setting for the evaporative cooling system.

2. Measure ambient temperature (38.0°C) and Relative Humidity (21 .4%) and determine from a look-up table that:

Wet Bulb is 21 .0°C

Dew Point is 12.2°C

Humidity Ratio (HR) is 0.0088354139 kg/kg (at 21 .4% RH)

Humidity Ratio (HR) is 0.0160545781 kg/kg (at 100% RH)

3. Calculate the difference in HR as 0.0072191642 kg/kg which is 7.22 cc per kg of air flow. If, for example the air flow is 46.4 m3/min, air weight is approximately 1 .293 kg/m ³ so the Air Flow Weight in kg/m3/min is 60.00. 60 x 7.22 (cc/min Possible to Evaporate) is 433 cc. 4. To obtain 433 cc/min fluid flow, the control system determines that, with 8 typical nozzles (for example) flow at 54 cc/min each would provide a total flow of 433 cc/min to take RH to 100% and therefore reach Wet Bulb.

5. The control system would utilise the spin rate of the rotary device to obtain that pressure and flow rate (a combination of centrifugal pressure + static water pressure (if any)) and run the system at that rate.

6. Should ambient conditions change, the control system can reassess and adjust both the spin rate of the rotary device and the spin rate/airflow rate of the fan to keep the system outputting air at Wet Bulb.

[0062] It is worth noting that increasing rotary device RPM increases centrifugal pressure that in turn increases fluid flow rate (and reduces droplet size for a finer mist)).

[0063] The table below (Table 1 ) compares the relative performance numbers of an evaporative cooling system of the combined fan and nozzles design of WO 2012/156052 (titled: Combined) with two embodiments of an evaporative cooling system of the present invention incorporating the separated fan and rotary device supporting nozzles arrangement (titled: Separated 1 and 2) :

[0064] Table 1 :

FACTOR COMBINED SEPARATED

1 2

Fan RPM 800 800 800

Rotary Device RPM N/A 2000 3000 Fan Air Velocity (km/h) (A) 20 20 20

Nozzle Velocity (km/h) (B) 59 149 223

Mist Exit Velocity (km/h) (C) 62 105 143

Nozzle Pressure inc. 52psi mains (psi) 72 178 335

Nozzle Pressure (kPa) 496.4 1227.3 2309.7

Nozzle Flow Rate (cc/min) 18 31 42

TOTAL VELOCITIES (A+B+C) 141 274 386

KEY VELOCITIES (A+B) 79 169 243

[0065] As can be seen above in Table 1 , the much higher RPM of the rotary device results in higher fluid flow rate through the nozzles (due to higher pressure) and higher mist exit velocity from the nozzles.

[0066] The mist exit velocity is of course only at the very tip of the nozzle and this velocity reduces extremely rapidly in the first millimetre or so of mist travel (mist droplets are typically only 20-60 μιη so have very low inertia and therefore decelerate very rapidly after ejection from the nozzles). Consequently, although showing as a very high velocity in the table (105 km/h and 143 k/h) it has been ignored in the 'Key Velocities' row. As shown in Table 1 , the comparison is 79 vs 169 km/h. Therefore, the worst case for the embodiments of the present invention in Table 1 is that the total key velocity comparison is approximately a factor of 2 with the rotary device spinning at 2.5 times the RPM of the fan (2000 vs 800) but the factor would be approximately 3 if the rotary device spins at 3000 RPM (3.75 times the RPM of the fan). This clearly demonstrates just how superior the performance of the present invention can be in comparison to the original combined fan and nozzles system of WO 2012/156052. [0067] From a mechanical construction point of view, it is more versatile and much better from a control system perspective to have separate drives, such as individual electric motors, for the fan and the rotary device.

[0068] However, it is possible that a single motor can drive both using a gearing system, such as a planetary gearbox, e.g. driving the rotary device. For example, the single electric motor could be spinning at 800 RPM so that the fan is also spinning at 800 RPM but the rotary device gearing system at 2,400 RPM using a 3:1 ratio gearbox. While this can therefore provide higher performance, it cannot offer the system optimization possibilities offered via a control system that is configured to separately control the fan and the rotary device by varying relative speeds of the fan and separate rotary device.

[0069] Liquid can feed into the central hub of the rotary device via a feed conduit, such as a hollow shaft motor (such that the liquid passes through the electric motor).

[0070] Alternatively, the liquid can enter via the other side of the hub of the rotary device (relative to the motor), without requiring a hollow shaft motor, though the liquid still enters the rotary device via a hollow shaft/tube for dispersal to the nozzles.

[0071 ] While not mandatory, a relatively flat 'pancake motor' to drive the rotary device lowers the overall thickness of the componentry for a smaller, neater, improved looking system. Further, the motor can even be incorporated as part of the rotary device itself e.g. combined into the hub.

[0072] A further aspect of the present invention provides a method of providing evaporative cooling of an airflow, the method including the steps of rotating a fan to provide the airflow, rotating a rotary device having nozzles, and spraying a mist of a liquid from the nozzles for evaporation in the airflow, whereby the rotary device is rotated at a different rate/speed of rotation than that of the fan.

[0073] Preferably, the fan is rotated (such as by a motor or belt drive) to rotate at a desired or controlled first rate (RPM).

[0074] Preferably the rotary device is driven to rotate at a desired or controlled second rate (RPM).

[0075] Preferably, the rotary device is rotated at a higher rate of rotation than the fan. More preferably the rotary device is rotated within a range of 2-100 times faster than the fan, more preferably within a range of 2-50 times faster, and yet more preferably within a range of 2-10 times faster, or within a preferred range of 2-4 times faster.

[0076] Direction of rotation of the rotary device and the fan can be the same direction or can be opposite (contra) directions.

[0077] The rotary device can be stopped or at least not powered to rotate, and misting can be ceased if just airflow from the fan is required (such as during very humid weather/environmental conditions or on a cool day when further

evaporative cooling is not required but airflow/venting is required).

[0078] The fan may be powered to rotate by a motor (such as by an hydraulic, pneumatic or electric motor).

[0079] Drive may be provided from the motor for the fan to the rotary device, such as by gearing. [0080] Alternatively, the fan and the rotary device may be separately powered, such as by separate motors (e.g. hydraulic, pneumatic or electric motors).

[0081 ] The rotary device may include a hub or housing incorporating the motor.

[0082] The evaporative cooling system may include or be controlled by a control system.

[0083] The control system may control the rate of rotation of the fan and/or the rotary device, such as by controlling the respective motor(s).

[0084] The control system may control the direction of rotation of the fan and/or the rotary device, such as by controlling the respective motor(s).

[0085] A valve may be provided to control supply of the liquid to the rotary device (and therefore to the nozzles). For example, the control system may include a controller to allow or prevent supply of the liquid to the rotary device, or control supply rate or volume thereof.

[0086] Various modifications may be made in details of design and

construction without departing from the scope or ambit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which : [0088] Figures 1 and 2 show respective side and perspective views of an embodiment of the present invention.

[0089] Figures 3 and 4 show respective side and perspective views of an alternative embodiment of the present invention.

[0090] Figure 5 shows a side view of an evaporative cooling system according to an alternative embodiment of the present invention.

[0091 ] Figure 6 shows a side view of an evaporative cooling system according to another alternative embodiment of the present invention.

[0092] Figures 7 and 8 show respective side and perspective views of an alternative embodiment of the present invention.

[0093] Figure 9 shows a still further embodiment of the present invention.

[0094] Figure 10 shows a plan view cross section through an embodiment of the present invention.

[0095] Figure 1 1 shows a side view with sectional view through the rotary device showing passageways/conduits for liquid supply from the inlet to the nozzles according to an embodiment of the present invention.

[0096] Figure 12 shows an alternative embodiment of the present invention with the rotary device for spraying/misting liquid on the upstream side of the fan.

DESCRIPTION OF PREFERRED EMBODIMENT [0097] Figures 1 and 2 show an evaporative cooling system according to an embodiment of the present invention. A fan 0.1 has a fan hub 1 .1 and fan blades 2.1 mounted on and driven by the fan motor 3.1 .

[0098] A rotary device 4.1 incorporates a hollow shaft inlet 5.1 with the liquid passing through the motor to the rotary device 4.1 for dispersal to the nozzles 8.1 .

[0099] The rotary device can be driven by a pancake style motor 6.1 .

[00100] Distribution tabs/winglets 7.1 (small foil shaped tabs/winglets pointing slightly down to be closer to the trailing edge of the fan blades) distribute liquid to the nozzles 8.1 to emit a mist 13.1 .

[00101 ] A controller 16.1 can control fan motor speed and/or direction and/or rotary device motor speed and/or direction, and can control difference in speeds between the fan and the rotary device.

[00102] Also shown is the spin direction arrow 9.1 of the fan and spin direction arrow 10.1 of the rotary device. However, the rotary device may spin in a contra/opposite direction to that of the fan.

[00103] Air flow direction arrows 1 1 .1 represent the airflow from the fan through a cross-section of a section of circular chute/duct 12.1 in which the system is located, such as by a location array 20.1 to hold and locate the system in place.

[00104] As shown by way of example in Figures 3 and 4, a further embodiment of the present invention provides an evaporative cooling system having a fan 0.2 with a fan hub 1 .2 and fan blades 2.2 mounted on and driven by a fan motor 3.2.

[00105] A separate rotary device 4.2 incorporates a hollow shaft inlet 5.2 and is provided with a pancake style, low profile, electric motor 6.2 on the opposite side of the rotary device to the hollow shaft inlet for the liquid to be supplied to the nozzles 8.2.

[00106] Distribution tabs/winglets 7.2 (for example, small foil shaped horizontal tabs/winglets for ease of production and low cost) provide conduits for liquid to supply the nozzles 8.2.

[00107] The nozzles 8.2 are configured to emit a mist 13.2 of liquid droplets.

[00108] Also shown is the spin direction arrow 9.2 of the fan and spin direction arrow 10.2 of the rotary device. However, as described for the previous embodiment, the rotary device and the fan may be configured in the evaporative cooling system to spin in contra/opposite directions.

[00109] Airflow direction arrows 1 1 .2 are shown for the airflow through a cross- section of a section of circular chute/duct 12.2 that the system is preferably located within.

[001 10] Figure 5 shows a further embodiment of the present invention.

[001 1 1 ] A fan 0.3 has a fan hub 1 .3 and fan blades 2.3 mounted on and driven by the fan motor 3.3.

[001 12] A separate rotary device 4.3 incorporates a hollow shaft inlet 5.3 for liquid to enter the rotary device, passing through a pancake style electric motor 6.3, for supplying the nozzles. The pancake style electric motor 6.3 is provided to rotate the rotary device.

[001 13] Distribution tabs/winglets 7.3 are provided as larger (relative to the foils/winglets on the previous embodiment) foil shaped tabs/winglets pointing slightly down to be closer to the trailing edge of the fan blades and also boost airflow of the combined fan system (fan + rotary device fan boost winglets)).

[001 14] Nozzles 8.3, in use, emit a mist 13.3 (such as a water mist).

[001 15] Spin direction arrow 9.3 shows the direction of spin of the fan and spin direction arrow 10.3 shows direction of spin of the rotary device. However, relative spin of these two components can be contra/opposite to each other.

[001 16] Figure 6 shows a further embodiment of the present invention. A fan 0.4 includes a fan hub 1 .4 and fan blades 2.4 mounted on and driven by the fan motor 3.4.

[001 17] A rotary device 4.4 is driven by a low profile pancake motor 6.4, and is supplied with liquid via a hollow shaft inlet 5.4.

[001 18] The shaft can be hollow to supply the liquid into the rotary device for dispersal internally to the nozzles, with the motor provided on the other side of the rotary device from the shaft, therefore, the liquid can enter the rotary device without needing to flow through the motor.

[001 19] Distribution tabs/winglets for liquid are provided in the form of tubes/conduits 7.4. These can be mildly foiled round (e.g. elliptical or ovoid in cross section) tubes for ease of production and low cost leading to nozzles 8.4 for emitting a mist 13.4 of droplets, such as water droplets for water under centrifugal pressure (plus any static head of pressure).

[00120] As shown by way of example in Figures 7 and 8, a further embodiment of the present invention includes a fan 0.5 with a hub 1 .5 and fan blades 2.5 mounted on and driven by the fan motor 3.5. [00121 ] A separate rotary device 4.5 is spaced from the fan and incorporates a shaft liquid inlet 5.5.

[00122] Distribution supports/tabs/winglets 7.5 (a minimal number of very low aerodynamic drag tabs/winglets) provide one or more conduits that distribute liquid from the hub to a ring 14.5 with nozzles 8.5.

[00123] The nozzles point towards the fan and emit a mist 13.5 in use (i.e. the liquid is sprayed into/against the airflow produced by the fan).

[00124] Figure 9 shows a further variant embodiment of the present invention.

[00125] The embodiment in Figure 9 provides a contra spinning version of the embodiment shown in Figure 5, being representative of the concept of contra rotating fan and rotary device encompassed within the present invention.

[00126] A fan 0.6 has a fan hub 1 .6 and fan blades 2.6.

[00127] The hub and blades are mounted to spin/rotate driven by a fan motor 3.6.

[00128] A separate rotary device 4.6 includes a hollow shaft liquid inlet 5.6 (e.g. for water to be distributed out through the rotary device to then be sprayed/emitted from the nozzles as a mist).

[00129] A low profile motor 6.6 drives rotation of the rotary device.

[00130] Distribution tabs/winglets 7.6 (e.g. tabs/winglets as in Figure 5 but reversed in direction, angled slightly down to be closer to the trailing edge of the respective fan blades and also to boost airflow of the combined fan rotary device with fan boost tabs/winglets. [00131 ] Nozzles 8.6 are provided to emit, in use, a mist 13.6 (such as water as a fine mist/spray).

[00132] Spin direction arrow 9.6 of the fan and the opposing spin direction arrow 10.6 of the rotary device are also represented.

[00133] Generally, at the inlet to the centre of the disk/hub of the rotary device (whether a hollow shaft through the motor or a hollow shaft inlet to the rotary device (disk/hub) itself without passing through the motor) one or more

mechanical seals can be present (such as one or more O-ring seals) to seal the spinning rotary device with respect to the static fluid inlet to prevent leakage and ensure supply of the liquid to the nozzles.

[00134] Supply of the liquid to the nozzles can be through one or more distribution channels/conduits (e.g. pathways for the liquid, the liquid preferably being water or mostly water) within or on the rotary device. For example, one or more tubes may be provided within the rotary device, or on an external surface of the rotary device, or the one or more distribution channels/conduits may be provided by an internal hollow structure of the rotary device or part of the rotary device, or a combination of two or more thereof.

[00135] Once the liquid enters the rotary device, the liquid can be split radially to supply corresponding outlying nozzles.

[00136] By way of example, Figure 10 shows a plan view of an evaporative cooling system embodying the present invention with the rotary device 4.2 in cross section showing supports/winglets 7.2 supporting the nozzles 8.2. Liquid is supplied through the inlet 5.2 via internal passageways/conduits 15.2 to the nozzles 8.2 for spraying/misting 13.2

[00137] Figure 1 1 shows the evaporative cooling system embodiment as represented in Figures 7 and 8 with a ring 14.5 including nozzles 8.5. Figure 1 1 includes a cross sectional view through the rotary device 4.5 with internal passageways/conduits 15.5 from the inlet 5.5 for the liquid to feed through to the nozzles 8.5 for misting/spraying 13.5 therefrom.

[00138] Figure 12 shows an alternative embodiment of the present invention with the rotary device for spraying/misting liquid on the upstream side of the fan. It will be appreciated that the inlet 5.2 is now a hollow shaft through the motor 6.2 driving the rotary device rather than a hollow shaft supplying liquid direct to rotary device without passing through the motor (with supply inlet on the opposite face of the rotary device from the motor as in Figure 3).

[00139] By way of example, and which can be applied to all embodiments of the present invention with separate drive motors for the fan and the rotary device, a controller 16.1 can control speed and/or rotation direction for the fan and/or the rotary device and/or difference in speed between the fan and the rotary device.

[00140] It will be appreciated that a similar controller can be provided to control the single motor embodiments that have gearing driving the rotary device at higher RPM than the fan.

[00141 ] The fluid distribution channels/conduits/passageways can be relatively narrow/thin (preferably internal) tube-like passages so as not to create too much physical pressure within the rotary device. Such relatively narrow/thin (preferably internal) tube-like passages can continue into, through or over, or a combination thereof, the foil/tabs/winglets/blades or distribution ring(s) to the nozzles themselves.

[00142] In use, the fan can be driven to rotate at a desired or controlled first RPM. The rotary device can be driven to rotate at a desired or controlled second RPM. The first and the second RPMs can be the same or can be different.

Direction of rotation of the rotary device and the fan can be the same direction or can be opposite directions, or the rotary device can be stopped or at least not powered to rotate and misting can be ceased if just airflow from the fan is required (such as during very humid weather/environmental conditions or on a cool day when further evaporative cooling is not required but airflow/venting is required).

[00143] A control system can include a controller to operatively control the fan and/or the rotary device and/or rate or volume of spray/mist from the nozzles. For example, the controller may be connected to the fan motor to control rate (RPM) and/or direction of fan rotation. The controller may be connected to the rotary device motor (where provided) to control rate (RPM) and/or direction of rotation of the rotary device.

[00144] The rotary device may have wings, winglets or tabs providing a booster fan function or to provide reduced capacity single fan and/or spray air

conditioning in the event of failure of the fan.