Field of the Invention

The present invention relates to a fan assembly.

Background of the Invention

Some fan assemblies may utilise a refrigeration system to provide a cooled airflow. The refrigeration system may employ a heat exchanger to remove heat from the airflow.

Summary of the Invention

The present invention provides a fan assembly comprising a refrigeration system comprising a heat exchanger, and an airflow generator for generating an airflow over the heat exchanger, wherein the heat exchanger surrounds a major portion of the airflow generator. Thereby, the airflow generator is nested within the heat exchanger, which may provide a compact arrangement and reduce the height of the fan assembly. This may increase the utility of the fan assembly by making it more easily accommodated within a domestic setting. Additionally, nesting the airflow generator centrally within the heat exchanger may improve the uniformity of the airflow over the heat exchanger and thereby the performance of the heat exchanger.

The heat exchanger may be cylindrical in shape. By having a cylindrical shape, the footprint of the fan assembly may be reduced whilst achieving a good area for the heat exchanger.

The heat exchanger may subtend a central angle of at least 270°. As a result, the height and footprint of the fan assembly may be reduced whilst achieving a good area for the heat exchanger.

The fan assembly may comprise a filter assembly for filtering the airflow, and the filter assembly may surround a major part of the heat exchanger. The filter assembly therefore presents a restriction to the airflow that moves over the heat exchanger. As a result, the airflow may be more uniformly distributed over the heat exchanger. Thereby, the performance of the heat exchanger may be improved. Additionally, this may provide a compact and cost-effective arrangement as the filter assembly may be used for dual purposes: providing a restriction to improve the performance of the heat exchanger and filtering the airflow.

The fan assembly may comprise an axial gap between an inlet of the airflow generator and a wall facing the inlet, and a ratio of the axial gap to a diameter of the inlet may be no less than 1 :2.3. The term ‘axial’ should be understood to mean in a direction normal to the inlet. With a ratio less than 1 :2.3, the inventors have observed that the airflow between the wall and the inlet may become pinched, leading to an increase in the velocity and distortion of the airflow. This increase in velocity and distortion results in several negative effects. Firstly, the noise generated by the airflow increases, which may be undesirable for a user of the fan assembly. Secondly, the airflow over the heat exchanger may become non-uniform. Specifically, the flow rate of the airflow through the bottom of the heat exchanger increases, whilst the flow rate of the airflow at the top of the heat exchanger decreases. As a result, the performance of the heat exchanger decreases. Therefore, by having a ratio of no less than 1:2.3, the uniformity of the airflow over the heat exchanger may be improved, which may improve the performance of the heat exchanger. Additionally, the noise produced by the airflow generator may be reduced.

The ratio may be no greater than 1 : 1. As a result, the height of the fan assembly may be reduced whilst achieving a good inlet area. Furthermore, having a ratio of between 1 :2.3 and 1 : 1, and more particularly between 1 :2 and 1 : 1.1, may provide a good balance between the competing needs of reducing the height of the fan assembly to provide a compact arrangement, whilst also preventing pinching of the airflow.

The axial gap may be no less than 30mm. This may provide one or more of the benefits described above (e.g., improved heat exchanger performance, and/or reduced noise) in a fan assembly sufficiently large to provide a useful airflow rate for use in a domestic setting (e.g., to control the temperature of a room). The axial gap may be no greater than 70mm. The height of the fan assembly may therefore be reduced. Furthermore, having an axial gap of between 30mm and 70 mm may provide a good balance between the competing needs to reduce the height of the fan assembly to provide a compact arrangement, whilst also preventing pinching of the airflow.

A ratio of the axial gap to a height of the heat exchanger may be no less than 1 :4. The inlet of the airflow generator is therefore not located too low down the heat exchanger. As a result, the uniformity (with respect to the height of the heat exchanger) of the airflow over the heat exchanger may be improved, which may improve the performance of the heat exchanger.

The ratio (i.e., the ratio of the axial gap to the height of the heat exchanger) may be no greater than 1 :3. The inlet of the airflow generator is therefore not located too high up the heat exchanger. Thereby, a significant portion of the airflow generator may be located within the heat exchanger. This may reduce the height of the fan assembly. Furthermore, having a ratio of between 1 :4 and 1 :3, and more particularly between 1 :3.8 and 1 :3.1, may provide a good balance between the competing needs to reduce the height of the fan assembly, whilst also providing uniform airflow over the heat exchanger.

The fan assembly may comprise a radial gap between the airflow generator and the heat exchanger, and a ratio of the radial gap, at an inlet of the airflow generator, to a height of the heat exchanger may be no less than 1 :5. The term ‘radial’ should be understood to mean in a direction parallel to the inlet. Furthermore, the radial gap at the inlet of the airflow generator is that radial gap between the airflow generator and the heat exchanger when measured in the plane of the inlet. For ratios less than 1 :5, the inventors have observed that the airflow over the heat exchanger becomes non-uniform with respect to the height of the heat exchanger, which may result in a reduction in the performance of the heat exchanger. Therefore, by having a ratio of no less than 1 :5, the uniformity of the airflow over the heat exchanger may be improved, which may improve the performance of the heat exchanger. The ratio (i.e., the ratio of the radial gap to the height of the heat exchanger) may be no greater than 1 :3. As a result, the footprint of the fan assembly may be reduced, whilst also achieving a good area for the heat exchanger. Furthermore, having a ratio of between 1 :5 and 1 :3 may provide a good balance between the competing needs of improving the uniformity of the airflow over the heat exchanger, and providing a compact arrangement.

The radial gap may be no less than 20mm. The benefit described above (i.e., improving the uniformity of the airflow over the heat exchanger) may therefore be provided in a fan assembly sufficiently large to provide a useful airflow rate for use in a domestic setting.

The radial gap may be no greater than 50mm. As a result, the footprint of fan assembly may be reduced. Furthermore, having a radial gap of between 20mm and 50mm may provide a good balance between the competing needs of improving the uniformity of the airflow over the heat exchanger, and providing a compact arrangement.

The fan assembly may comprise a main body within which the refrigeration system and the airflow generator are located. The main body may comprise an inlet through which the airflow is drawn into the main body and an outlet through which the airflow is emitted from the main body. The inlet may be located in a side of the main body, and the outlet may be located in a top of the main body. The fan assembly may comprise a nozzle attached to the main body and receiving the airflow emitted from the main body. The nozzle may comprise an outlet through which the airflow is emitted from the fan assembly. As a result, a relatively large area for the heat exchanger may be achieved whilst also ensuring a relatively small footprint. Providing a nozzle may enable improved control over the direction of the emitted airflow. For example, the nozzle may be moveable or comprise moveable parts (e.g. slats or louvres) to change the direction of the airflow. This then enables the emitted airflow to be targeted in different directions. Additionally, with this arrangement the refrigeration system and airflow generator are located relatively low down, which may provide a lower centre of gravity and thereby may improve the stability of the fan assembly. The airflow generator may be configured to generate an airflow having a flow rate of no less than 20 L/s. Thereby, the fan assembly may provide effective cooling of a user and/or heating of a relatively large volume, such as a room.

The refrigeration system may comprise a compressor and a further heat exchanger. The further heat exchanger may surround a major portion of the compressor. By comprising a further heat exchanger and a compressor, the refrigeration system may operate a refrigeration cycle in which heat is transferred between the airflow and a medium located at the further heat exchanger (e.g. a thermal store). For example, heat may be transferred from the airflow at the heat exchanger to cool the airflow, and heat may be transferred to the medium at the further heat exchanger to heat the medium. By surrounding a major portion of the compressor with the further heat exchanger, a relatively compact arrangement may be achieved.

The fan assembly may comprise a condensation collector for collecting condensate that forms on the heat exchanger, and the condensation collector may comprise a tray located between the heat exchanger and the further heat exchanger. Thereby, condensate formed on the heat exchanger during use is collected and thereby may be prevented from damaging other components of the fan assembly. Additionally, this may enable the collected condensate to be disposed of (e.g., by removing and emptying the tray) and thereby may reduce the generation of bacteria and malodour. Locating the condensation collector between the two heat exchangers makes better use of the available space within the fan assembly and thereby may provide a more compact arrangement.

The condensation collector may comprise a bottle. The tray may comprise a drain through which condensate collected by the tray drains into the bottle. The bottle may be located in a gap in the further heat exchanger. This may provide several benefits. Firstly, providing a bottle for the collection of condensate may enable a higher quantity of condensate to be collected. Secondly, locating the bottle within a gap in the further heat exchanger may provide a compact arrangement. Thirdly, the bottle may be located lower down in the fan assembly such that the weight of the collected condensate does not adversely affect the stability of the fan assembly, and may indeed improve the stability.

The refrigeration system may comprise a further heat exchanger, a compressor for moving a refrigerant between the heat exchanger and further heat exchanger, and a metering device for reducing a pressure of the refrigerant. Thereby, the refrigeration system is able to operate a refrigeration cycle in which heat is transferred from the airflow to a hotter medium located at the further heat exchanger (e.g. a thermal store). For example, heat may be transferred from the refrigerant to the medium at the further heat exchanger. The pressure and temperature of the refrigerant may then be reduced by the metering device, and heat may be transferred to the refrigerant from the airflow at the heat exchanger. Finally, the pressure and temperature of the refrigerant may be increased by the compressor, and heat may again be transferred from the refrigerant to the medium at the further heat exchanger. By transferring heat to a hotter medium, cooling of the airflow may be achieved without the need for a medium at a lower temperature than the airflow.

Brief Description of the Drawings

Figure l is a front perspective view of a fan assembly;

Figure 2 is a rear perspective view of the fan assembly with the components of the fan assembly removed;

Figure 3 is a front perspective view of the fan assembly with components of the fan assembly removed;

Figure 4 is a block diagram of components of the fan assembly;

Figure 5 is a schematic of a refrigeration system of the fan assembly in a first state;

Figure 6 is a schematic of the refrigeration system in a second state;

Figure 7 is a vertical section through part of the fan assembly;

Figure 8 is a horizonal section through the fan assembly; and

Figure 9 is a perspective view of an alternative fan assembly with an alternative condensation collector visible. Detailed Description of the Invention

The fan assembly 10 of Figures 1 to 4 comprises a nozzle 11 and a main body 15.

The nozzle 11 is attached to the main body 15 and comprises an inlet 12 for receiving an airflow from the main body, and an outlet 13 for emitting the airflow. In the example of Figure 1, the nozzle 11 is generally racetrack shaped, the inlet 12 comprises an opening in a base of the nozzle 11, and the outlet 13 comprises a pair of slots that each extend along straight portions of the nozzle 11. In some examples, the nozzle 11 may comprise slats, louvres or other means for changing the direction of the airflow emitted from the outlet 13. Thereby, the direction of the airflow may be changed without the need to rotate the nozzle 11 or main body 15.

The main body 15 comprises a housing 17, a pair of filter assemblies 18,19, an airflow generator 20, a refrigeration system 21, a condensation collector 77,79, and a control unit 23.

The housing 17 houses the filter assemblies 18,19, the airflow generator 20, the refrigeration system 21, the condensation collector 77,79, and the control unit 23. The housing 17 comprises an inlet 25 through which an airflow is drawn into the main body 15, and an outlet 26 through which the airflow is emitted into the nozzle 11. In the illustrated example, the housing 17 is cylindrical in shape, the inlet 25 comprises a plurality of apertures in a side wall of the housing 17, and the outlet 26 comprises an opening in a top wall of the housing 17.

Each of the filter assemblies 18,19 comprises a filter medium 24 supported by a frame 27, and a seal 28 provided around the perimeter of the frame 27. Each of the filter assemblies 18,19 is removably attached to a section of the housing 17, which in turn is removable from the main body 15. As a result, the sections of the housing may be removed, and the filter assemblies 18,19 removed from the sections for cleaning and/or replacement. Each of the filter assemblies 18,19 is arcuate and subtends a central angle of roughly 180°. The filter assemblies 18,19 surround a heat exchanger 49 of the refrigeration system 21 (described below in more detail) and the airflow generator 20.

In this example, the filter medium 24 is a HEPA filter medium that removes particulates, such as pollutants and bacteria, from the airflow. However, other or additional filter media could be employed, such as an activated carbon filter medium for removing undesirable gases, such as volatile organic compounds, from the airflow.

The seal 28 of each filter assembly 18,19 seals against the main body 15 and reduces potential leak paths, in which air is drawn into the main body 15 but bypasses the filter assemblies 18,19. Thereby the purity of the airflow emitted from the fan assembly 10 may be improved.

The airflow generator 20 comprises an impeller driven by an electric motor. The airflow generator 20 generates an airflow between the inlet 25 of the housing 17 and the outlet 26 of the main body 15. More particularly, the airflow is drawn into the housing 17 via the inlet 25 of the housing 17, whereupon the airflow is drawn through the filter assemblies 18,19 to remove particulates from the airflow. The airflow is then drawn over the heat exchanger 49 of the refrigeration system 21 to condition the airflow. The conditioned airflow then moves through the airflow generator 20, and is emitted from the main body 15 via the outlet 26.

By locating the filter assemblies 18,19 upstream of the heat exchanger 49, the filter assemblies 18,19 presents a restriction to the airflow that moves over the heat exchanger 49. As a result, the airflow may be more uniformly distributed over the heat exchanger 49, thereby improving the performance of the heat exchanger 49.

The refrigeration system 21, which is described below in more detail, is operable in one of two states to condition the airflow. In a first operating state, the refrigeration system 21 cools the airflow, and in a second operating state, the refrigeration system 21 warms the airflow.

The condensation collector 77,79 collects condensate that forms on the heat exchanger 49 and comprises a tray 77 and a bottle 79. The tray 77 is located beneath the heat exchanger 49 and acts to collect condensate that falls from the heat exchanger 49. The tray 77 has a sloped upper surface that guides the collected condensate to a drain 78 in the tray 77. The bottle 79 is located directly beneath the drain 78 such that condensate collected by the tray 77 drains into the bottle 79 via the drain 78.

In this example, the tray 77 has a generally circular shape with a pair of triangular holes for allowing components of the refrigeration system to pass through the tray 77.

The tray 77 and the bottle 79 are each removable from the fan assembly 10, e.g. in radial directions. The tray 77 and the bottle 79 may therefore be removed and emptied to remove collected condensate from the fan assembly 10. As a result, condensate can be collected and removed from the fan assembly 10 without requiring the fan assembly 10 to be connected to an external drain. The fan assembly 10 may therefore be self-contained, and thereby the portability of the fan assembly 10 may be improved. Additionally, moving the whole fan assembly 10 to remove condensate is not required. As the fan assembly 10 may be relatively heavy, this may improve the usability of the fan assembly 10. Furthermore, the tray 77 and the bottle 79 can be removed for cleaning, which may prevent of bacteria and malodour build up within the fan assembly 10.

The tray 77 is received within a slot in the main body 15 that is located inwardly of the filter assemblies 18,19. Accordingly, in order to remove the tray 77, the user must first remove one of the filter assemblies 18,19. The tray 77 is therefore located downstream of the seal 28 of the filter assembly 18 and thus does not present a leak path through which the airflow may bypass the filter assemblies 18,19. The bottle 79 is received within a recess 80 in the main body 15. To facilitate the removal of the bottle 79, the bottle 79 comprises a slidable locking portion 82 which engages a slot 84 in the housing 17. To detach and attach the bottle 79, the user slides the locking portion 82 into and out of the slot 84. The bottle also comprises a spout 86 which engages with the drain 78 of the tray 77.

In this example, the condensation collector 77,79 has a capacity of 400 mL. Specifically, the tray 77 has a capacity of 100 ml and the bottle 79 has a capacity of 300 mL. This may improve the usability of the fan assembly 10, as the condensation collector 77,79 may be emptied relatively infrequently. Indeed, the size of the condensation collector 77,79 may be sufficiently large to collect all condensation generated in a full day of use of the fan assembly 10. Equally, the condensation collector 77,79 may have a capacity of greater than 200 mL and realise the above benefit of relatively infrequent emptying.

Turning now to Figure 4, the control unit 23 comprises a controller 29, a wireless interface 31, and a temperature sensor 33.

The controller 29 is responsible for controlling the operation of the fan assembly 10. The controller 29 is connected to the airflow generator 20, the refrigeration system 21, the wireless interface 31, and the temperature sensor 33. The controller 29 controls the airflow generator 20 and the refrigeration system 21 in response to data received from the wireless interface 31 and the temperature sensor 33. For example, the controller 29 may power on and off the airflow generator 20, control the speed of the airflow generator 20, and/or control the operating state of the refrigeration system 21.

The wireless interface 31 receives command data from one or more remote devices 35. In examples, the remote devices 35 may comprise a user-operated device. For example, the remote devices 35 may comprise a dedicated remote control or a mobile device, such as a phone or tablet, running a suitable application. A user may then use the remote device to control remotely the operation of the fan assembly 10. For example, the device may be used to power on and off the fan assembly 10, control the speed and/or the direction of the airflow, as well as schedule operation of the fan assembly 10. In other examples, the remote devices 35 may comprise a room thermostat or other remote temperature sensor, which transmits temperature data to the wireless interface 31. The controller 29 may then operate the fan assembly 10 in response to changes in the temperature data. For example, the controller 29 may control the airflow generator 20 and/or the refrigeration system 21 such that a temperature within a room is maintained at a target temperature.

The temperature sensor 33 forming part of the control unit 23 monitors a temperature of the refrigeration system 21, discussed in more detail below, and outputs temperature data to the controller 29.

The control unit 23 may additionally comprise a user interface for controlling the operation of the fan assembly 10. For example, the user interface may comprise buttons, dials, a touchscreen or the like for powering on and off the airflow generator 20, as well as controlling the speed and/or direction of the airflow.

The fan assembly 10 is operable in one of a cooling mode and a regeneration mode.

In cooling mode, the controller 29 operates the refrigeration system 21 in the first state and operates the airflow generator 20 at a first speed. Thereby an airflow is drawn in through the inlet 25, through the filter assemblies 18,19, over the heat exchanger 49 of the refrigeration system 21 and emitted from the outlet 13 of the nozzle 11. As the refrigeration system 21 is operating in the first state, the airflow is cooled by the refrigeration system 21 and thus a cooled airflow is emitted from the nozzle 11. The speed of the airflow generator 20 in the cooling mode may be defined by the command data received by the controller 29. In this way, the speed of the airflow generator 20 may be controlled to achieve different cooling rates or profiles.

In regeneration mode, the controller 29 operates the refrigeration system 21 in the second state and operates the airflow generator 20 at a second speed. Again, an airflow is drawn in through the inlet 25, though the filter assemblies 18,19, over the heat exchanger 49 of the refrigeration system 21 and is emitted from the outlet 13 of the nozzle 11. As the refrigeration system 21 is operating in the second state, the airflow is warmed by the refrigeration system 21 and thus a warmed airflow is emitted from the nozzle 11. Regeneration mode is used to expel heat that was stored by the refrigeration system 21 during cooling mode. The speed of the airflow generator 20 in regeneration mode may be lower than that used in cooling mode, i.e. the second speed may be lower than the first speed. For example, the airflow generator 20 may operate at a relatively low or trickle speed in regeneration mode. As a result, the noise generated by the fan assembly 10 when operating in regeneration mode may be reduced.

The fan assembly 10 is intended to be used primarily to provide a cooled airflow. This cooled airflow may be used, for example, to cool a room. To achieve this, the fan assembly 10 operates in cooling mode. In cooling mode, as described above, the airflow is drawn over the heat exchanger 49, which extracts heat from the airflow, and the now cooled airflow is emitted from the nozzle 11. The extracted heat is stored within the refrigeration system 21. Cooling then continues until either cooling is no longer required (e.g. the fan assembly is turned off, or the temperature within the room has reached a target setpoint), or the maximum heat storage capacity of the refrigeration system 21 has been reached. As described below in further detail, the heat stored by the refrigeration system 21 may be sensed by the temperature data output by the temperature sensor 33, and the controller 29 may determine that the maximum heat storage capacity of the refrigeration system 21 has been reached when the temperature exceeds an upper threshold.

During periods when cooling is not required, or when the maximum heat storage capacity of the refrigeration system 21 has been reached, the fan assembly 10 may operate in regeneration mode. In regeneration mode, the fan assembly expels the heat that was stored during cooling. As a result, the fan assembly 10 is restored to a state in which cooling is possible. Regeneration mode may continue until either cooling is required or the full heat storage capacity of the refrigeration system 21 has been restored. As described below, the controller 29 may determine that the heat storage capacity of the refrigeration system 21 has been fully restored when the temperature drops below a lower threshold.

As a warmed airflow is emitted from the fan assembly 10 when operating in regeneration mode, regeneration may occur at times when the room is unoccupied (or unlikely to be occupied) or at times when warming is actually desirable. For example, the fan assembly be scheduled to operate in cooling mode during the day, and regeneration mode during the night. In a further example, geofencing may be employed, and the fan assembly 10 may operate in regeneration mode when a user is no longer present in the room or building in which the fan assembly 10 is located.

Turning now to Figures 5 and 6, reference will now be made to the composition and operation of the refrigeration system 21. The refrigeration system 21 comprises a circuit 41 and a thermal store 43.

The circuit 41 comprises a series of pipes 45, a first heat exchanger 46, a compressor 47, a metering device 48, and a second heat exchanger 49.

The series of pipes 45 connect the compressor 47 to the first heat exchanger 46, the first heat exchanger 46 to the metering device 48, the metering device 48 to the second heat exchanger 49, and the second heat exchanger 49 to the compressor 47 such that a refrigerant can circulate around the circuit 41.

The first heat exchanger 46 is downstream of the compressor 47 and upstream of the metering device 48, and exchanges heat between the refrigerant and the thermal store 43. The second heat exchanger 49 is located downstream of the metering device 48 and upstream of the compressor 47, and exchanges heat between the refrigerant and the airflow moving through the fan assembly 10. The compressor 47 drives the refrigerant around the circuit 41 in a direction indicated by the arrow in Figures 5 and 6. The refrigerant circulates from the compressor 47 to the first heat exchanger 46, from the first heat exchanger 46 to the metering device 48, from the metering device 48 to the second heat exchanger 49, and from the second heat exchanger 49 to the compressor 47. Depending on the state of operation, discussed subsequently, the compressor 47 may additionally compress the refrigerant.

The metering device 48 is operable in a restricted state and an unrestricted state. In the restricted state, the refrigerant flowing through the metering device 48 expands and the pressure and temperature of the refrigerant decreases. In the unrestricted state, the refrigerant flowing through the metering device 48 does not expand and the pressure and temperature of the refrigerant is unchanged. In this example, the metering device 48 comprises a variable expansion valve. In the restricted state, the variable expansion valve has a first restriction, and in the unrestricted state, the variable expansion valve has a second, less restrictive restriction. In other examples, the metering device 48 may comprise a capillary tube and the refrigeration system 21 may comprise a bypass valve for bypassing the metering device 48 in the second state.

The thermal store 43 stores thermal energy for transfer to and from the refrigerant in order to heat and cool the refrigerant. In this particular example, the thermal store 43 comprises a phase change material. This then has the benefit that the thermal store 43 can take advantage of the latent heat capacity of the phase change material to store more thermal energy for a given change in temperature. As a result, the refrigeration system 21 may provide cooling at the second heat exchanger 49 for a longer period. Nevertheless, the refrigeration system 21 may operate with a thermal store 43 that does not comprise a phase change material. The phase change material may have a melting point greater than the ambient temperature of the room. This then has the advantage that heat stored by the thermal store may be expelled to the room in regeneration mode. A relatively high melting point has the advantage of increasing the rate at which heat is expelled in regeneration mode, and thus decreasing the time required to regenerate the thermal store. A relatively low melting point, on the other hand, has the advantage of improving the efficiency of the refrigeration system in cooling mode. A relatively good balance between these two competing factors may be achieved with a phase change material having a melting point of between 30°C and 80°C. In some examples, the phase change material may comprise an organic wax or inorganic salt hydrate

In addition to the functions described above, the controller 29 controls the compressor 47 and the metering device 48. For example, the controller 29 may power on and off the compressor 47, as well as control the state of the metering device 48 and the speed of the compressor 47 in response to control data received from the wireless interface 31 and the temperature sensor 33.

As discussed above, the refrigeration system 21 is operable in a first state and a second state.

In the first operating state, shown in Figure 5, the controller 29 moves the metering device 48 to the restricted state. As a consequence of the metering device 48 being in the restricted state, the pressure and temperature of the refrigerant flowing though the metering device 48 decreases. In this particular example, the refrigerant remains in the liquid state, but could conceivably undergo a phase transition from a liquid state to a liquid-vapour state. The refrigerant flowing through the second heat exchanger 49 is at a lower temperature than the airflow moving over the second heat exchanger 49. Consequently, the second heat exchanger 49 acts as an evaporator to cool the airflow, and heat and vaporise the refrigerant. The refrigerant therefore undergoes a phase transition from a liquid state to a vapour state. The refrigerant then flows from the second heat exchanger 49 to the compressor 47, whereupon the refrigerant is compressed to increase the pressure, and thus the temperature, of the refrigerant. The refrigerant then flows through the first heat exchanger 46, which exchanges heat between the refrigerant and the thermal store 43. The refrigerant flowing through the first heat exchanger 46 is at a higher temperature than the thermal store 43. As a result, the first heat exchanger 46 acts as a condenser to heat the thermal store 43, and cool and condense the refrigerant. The refrigerant therefore undergoes a phase transition from a vapour state to a liquid state. The refrigerant then flows to the metering device 48, and the cycle is repeated.

In the second operating state, shown in Figure 6, the controller 29 moves the metering device 48 to the unrestricted state. As a consequence of the metering device 48 being in the unrestricted state, the pressure and temperature of the refrigerant flowing though the metering device 48 is unchanged. In this particular example, the refrigerant is in a vapour state, but could conceivably be in a liquid-vapour or a liquid state. Refrigerant flowing through the second heat exchanger 49 is at a higher temperature than the airflow moving over the second heat exchanger 49. Consequently, the airflow is heated, and the refrigerant is cooled. In this particular example, the refrigerant is not cooled below its boiling point and thus the refrigerant does not condense or undergo a phase change. The refrigerant then flows from the second heat exchanger 49 to the compressor 47. Owing to the unrestricted state of the metering device 48, the compressor 47 does not compress the refrigerant. The refrigerant then flows through the first heat exchanger 46, which exchanges heat between the refrigerant and the thermal store 43. The refrigerant flowing through the first heat exchanger 46 is at a lower temperate than the thermal store 43. As a result, the thermal store 43 is cooled, and the refrigerant is heated. In this particular example, the refrigerant flowing through the first heat exchanger 46 is in a vapour state and does not therefore undergo a phase transition. The refrigerant then flows to the metering device 48, and the cycle is repeated.

As noted above, the fan assembly 10 is operable in one of two modes: cooling and regeneration. When operating in cooling mode, the controller 29 configures the refrigeration system in the first state. The controller 29 then monitors the temperature of the thermal store 43 (via the temperature sensor 33). In the event that the temperature of the thermal store 43 exceeds an upper threshold, the controller 29 powers off the airflow generator 20 and the refrigeration system 21 (i.e. the compressor 47), or alternatively switches from cooling mode to regeneration mode. The upper threshold may represent a temperature above which the refrigeration system 21 is no longer able to effectively or efficiently cool the airflow. In this regard, the efficiency of the refrigeration system 21 decreases as the difference in the temperatures of the two heat exchangers 46,49 increases. Alternatively, the upper threshold may represent a temperature above which the volume expansion of the thermal store 43 becomes excessive, or the temperature of the thermal store 43 becomes excessively hot, which may present a safety concern or may lead to adverse changes in the physical and/or chemical properties of the thermal store 43. Additionally or alternatively, the upper threshold may represent a temperature above which the pressure of the refrigerant becomes excessive.

When operating in regeneration mode, the controller 29 configures the refrigeration system in the second state. The controller 29 again monitors the temperature of the thermal store 43. In the event that the temperature drops below the lower threshold, the controller 29 powers off the airflow generator 20 and the refrigeration system 21, or alternatively switches from regeneration mode to cooling mode. As noted, the efficiency of the refrigeration system 21 increases as the difference in the temperatures of the heat exchangers 46,49 decreases. The lower threshold may therefore represent a temperature below which the refrigeration system 21 is again able to effectively or efficiently cool the airflow. Where the thermal store 43 comprises a phase change material, the upper and lower thresholds may be respectively greater and lower than the melting point of the phase change material. For example, where the phase change material has a melting point of 46°C, the upper threshold may be 48°C and the lower threshold may be 44°C.

Turning now to Figures 7 and 8, reference will now be made to how the various components of the fan assembly 10 are packaged.

The main body 15 comprises a tank 50 that contains the thermal store 43. The tank 50 is generally cylindrical in shape, but comprises a gap such that the tank 50 (and thus the thermal store 43) is c-shaped in cross-section. The tank 50 comprises an inner wall 51 and an outer wall 53 that are arranged concentrically. The inner wall 51 subtends a central angle of 360°, whilst the outer wall 53 subtends a central angle of 340°. Radial walls then extend between the ends of the outer wall 53 and the inner wall 51. The tank 50 is enclosed at the top and bottom by top and bottom walls 57,59. The tank 50 partly defines a chamber 67 within which the compressor 47 is located. The compressor 47 is therefore partially surrounded by the thermal store 43. In the example of Figures 7 and 8, the thermal store 43 may be regarded as a sleeve that surrounds a major portion of the compressor 47. This then has two benefits. Firstly, a relatively large thermal store 43 may be packaged within the main body 15 in a relatively compact manner. Secondly, the thermal store 43 may absorb noise generated by the compressor 47.

The first heat exchanger 46 is embedded within the thermal store 43 and comprises piping 65 through which the refrigerant flows. Owing to spacing required for turns in the piping 65, the thermal store 43 does not completely surround the compressor 47 but instead subtends a central angle of about 340° about the compressor 47. Conceivably, the thermal store 43 could completely surround the compressor 47. However, this would then result in a portion of the thermal store 43 that is not in direct thermal contact with the first heat exchanger 46. Although this may help further absorb noise from the compressor 47, the additional material may not necessarily increase the heat storage capacity of the thermal store 43. By omitting this additional material, the cost and weight of the fan assembly 10 may be reduced. Moreover, advantage may be taken of the gap in the thermal store 43 by using it to locate another component of the fan assembly 10. In this example, the recess 80 extends into the gap such that the bottle 79 of the condensation collector 77,79 is located in the gap. Furthermore, in this example, the conditioned airflow is emitted from the front of the fan assembly 10 whereas the gap is located towards the rear of the fan assembly 10. As a result, any noise that may escape through the gap may be directed away from a user of the fan assembly 10.

The thermal store 43 has a height at least equal to that of the compressor 47. As a result, noise emitted in a sideways direction from the compressor 47 may be absorbed by the thermal store 43. Furthermore, the thermal store 43 has a thickness of around 60mm measured radially from a longitudinal axis of the thermal store 43. A relatively thick thermal store 43 has the advantage of absorbing more of the noise generated by the compressor 47, as well as increasing the thermal mass of the thermal store 43. A relatively thin thermal store 43, on the other hand, has the advantage of reducing the cost and weight of the fan assembly 10, which in turn may improve the portability of the fan assembly 10. A thermal store having a thickness of between 20mm and 150mm provides a good balance between these competing factors.

The thermal store 43 comprises a high-density medium (e.g. a solid, liquid, or solid-liquid phase change material). As a result, relatively good sound absorption may be achieved at the lower frequencies typically generated by the compressor 47.

The first heat exchanger 46 is embedded within the thermal store 43. Consequently, the first heat exchanger 46 may be said to be cylindrical or annular in shape. By providing a thermal store 43 and/or a heat exchanger 46 that is cylindrical in shape, a relatively compact arrangement may be achieved. In particular, the thermal store 43 and/or the first heat exchanger 46 may surround one or more other components of the fan assembly 10, such as the compressor 47 in this instance.

The compressor 47 is located towards a base of the main body 15. The compressor 47 is a relatively heavy component of the fan assembly 10 and thus locating the compressor 47 towards the base of the main body 15 provides a lower centre of gravity which may improve the stability of the fan assembly 10. The compressor 47 is located within the chamber 67, bounded by the inner wall 51 of the tank 50. The top and bottom of the chamber 47 are then bounded by a first plate 73 and a second plate 75. The first plate 73 has one or more openings through which pipes 45 of the circuit 41 pass into and out of the chamber 67. By providing plates 73,75 directly above and below the compressor 47, noise emitted from the compressor 47 in the vertical directions may be absorbed.

The metering device 48 is located within the chamber 67. Thereby, noise generated by the metering device 48 (e.g. due to movement of the refrigerant through the metering device 48) may be absorbed by the thermal store 43 and plates 73,75. However, it is conceivable that the metering device 48 may be located outside of the chamber 67. The airflow generator 20 is located above the compressor 47, towards the top of the main body 15. The airflow generator 20 is located centrally along a longitudinal axis of the main body 15.

The second heat exchanger 49 is cylindrical or annular in shape and is positioned vertically above the thermal store 43 and the first heat exchanger 46. In this example, the first heat exchanger 46 and the second heat exchangers 49 are concentric. The second heat exchanger 49 then surrounds a lower part of the airflow generator 20. By stacking the heat exchangers 46,49 vertically in this way, and by locating components of the fan assembly 10 (e.g. airflow generator 20 and compressor 47) within the interior space defined by the heat exchangers 46,49, a relatively compact arrangement may be achieved. In particular, the footprint of the fan assembly 10 may be reduced.

The second heat exchanger 49 surrounds a major portion of the airflow generator 20. In this example, the second heat exchanger 49 subtends a central angle of roughly 300° about the airflow generator 20. In other examples, the second heat exchanger 49 may subtend a larger or smaller central angle. As the central angle decreases, however, the area of the second heat exchanger decreases. Accordingly, the second heat exchanger 49 may subtend a central angle of at least 270°. As a result, the height and footprint of the fan assembly 10 may be reduced whilst achieving a good area for the second heat exchanger 49.

The tray 77 of the condensation collector 77,79 is spaced from, and extends broadly parallel to, an inlet 22 of the airflow generator 20 such that the tray 77 may be considered to face the inlet 22 of the airflow generator 20. An axial gap 90 (i.e. measured in a direction normal to the inlet 22 or parallel to the rotational axis of the airflow generator 20) exists between the inlet 22 of the airflow generator 20 and the tray 77. In this example, the tray 77 has a sloped upper surface, so the axial gap 90 is measured between a centre of the inlet 22 and the tray 77. The axial gap 90 has a value of 35mm and the inlet 22 of the airflow generator 20 has a diameter of 68mm. Therefore a ratio of the axial gap 90 to the diameter of the inlet 22 is around 1 : 1.9. The applicant has observed that, if this ratio is too low, say below 1 :2.3, the airflow between the tray 77 and the inlet 22 of the airflow generator 20 may become pinched, leading to an increase in the velocity and distortion of the airflow. This increase in velocity and distortion results in several negative effects. Firstly, the noise generated by the airflow increases, which may be undesirable for a user of the fan assembly 10. Secondly, the airflow over the second heat exchanger 49 may become non-uniform. Specifically, the flow rate of the airflow over the lower part of the second heat exchanger 49 may be higher, whilst the flow rate of the airflow over the upper part of the second heat exchanger 49 may be lower. As a result, the performance of the second heat exchanger 49 decreases. By having a relatively high ratio, i.e. one that is at least 1 :2.3, the uniformity of the airflow over the second heat exchanger 49 may be improved, which may improve the performance of the second heat exchanger 49. Additionally, the noise produced by the airflow generator 20 may be reduced. As this ratio increases, however, the overall height of the fan assembly 10 is likely to increase. Accordingly, the ratio of the axial gap to the diameter of the inlet may be between 1 :2.3 and 1 : 1, and more particularly between 1 :2 and 1 : 1.1. Moreover, the axial gap 90 itself may be between 30mm and 70mm. This then provides a relatively good balance between the competing needs to reduce the height of the fan assembly 10 whilst also preventing pinching of the airflow.

The second heat exchanger 49 has a height 92 of 115mm. As a result, a ratio of the axial gap 90 to the height 92 of the second heat exchanger 49 is around 1 :3.3. The applicant has observed that, if this ratio is too low, say below 1 :4, the airflow over the second heat exchanger 49 may be non-uniform. Specifically, the flow rate of the airflow over the lower part of the second heat exchanger 49 may be higher, whilst the flow rate over the upper part of the second heat exchanger 49 may be lower. As this ratio increases, however, the overall height of the fan assembly 10 is likely to increase. A ratio of between 1 :4 and 1 :3, and more particularly between 1 :3.8 and 1 :3.1, may provide a good balance between the competing needs to reduce the height of the fan assembly 10, whilst also providing uniform airflow over the second heat exchanger 49. The fan assembly 10 additionally comprises a radial gap 94 between the airflow generator 20 and the second heat exchanger 49 of 30mm. Specifically, the radial gap 94 is in a direction parallel to the inlet 22 of the air flow generator 20 and is measured in a plane of the inlet 22 of the airflow generator 20. The fan assembly 10 therefore has a ratio of the radial gap 94 to the height 92 of the second heat exchanger 49 of around 1 :3.3. For relatively low ratios, the applicant has observed that the airflow moving over the second heat exchanger 49 may become non-uniform, which may result in a reduction in the performance of the second heat exchanger 49. However, relatively high ratios, on the other hand, are likely to increase the footprint of the fan assembly 10. Having a ratio of between 1 :5 and 1 :3 may provide a good balance between the competing needs of improving the uniformity of the airflow over the second heat exchanger 49, and providing a compact arrangement. Additionally, having a radial gap 94 of between 20mm and 50mm may also provide a good balance between the competing needs in a fan assembly sufficiently large to provide a useful airflow rate for use in a domestic setting.

The second heat exchanger 49 is located at approximately the same height as the inlet 25 in the housing 17. Consequently, the apertures in the housing 17 may be said to surround the second heat exchanger 49. As a result of this arrangement, a relatively straight, radial path may be taken by the airflow when moving from the inlet 25 to the airflow generator 20. By providing a relatively straight, less contorted path, pressure losses may be reduced and thus a higher flow rate may be achieved for the airflow.

The tray 77 of the condensation collector 77,79 is located beneath the second heat exchanger 49 and above the first heat exchanger 46 (i.e. between the first 46 and second 49 heat exchangers). Locating the tray 77 between the two heat exchangers makes better use of the available space within the fan assembly 10 and thereby may provide a more compact arrangement.

With the fan assembly 10 described above, the thermal store 43 performs two important functions. Firstly, the thermal store 43 stores heat transferred from the first heat exchanger 46, thereby obviating the requirement to expel the heat immediately into the surrounding environment. Secondly, the thermal store 43 absorbs noise generated by the compressor 47. Acoustic emissions from the fan assembly 10 may therefore be reduced without the requirement for separate noise-absorbing materials, such as acoustic foams.

In the example described above, the thermal store 43 subtends a central angle 61 of 340°. However, the thermal store 43 may subtend a smaller angle, or indeed a larger angle. For example, the thermal store 380 may subtend an angle of, say, at least 180°. As a result, noise generated by the compressor 47 may be absorbed around at least one half of the fan assembly 10. The fan assembly 10 may then be sited adjacent a wall within a room and oriented such that the portion of the compressor 47 covered by the thermal store 43 is directed towards the centre of the room, whereas the uncovered portion may be directed towards the wall. Significant acoustic improvements may therefore be achieved without necessarily requiring the thermal store 43 to surround wholly the compressor 47.

In the above example the first and second plates 73,75 cover the top and bottom of the chamber 67. However, conceivably the one or both of the plates 73,75 may be omitted. Moreover, the thermal store 43 may be arranged to cover at least part of the top and/or bottom of the chamber 67. This may then further reduce the emission of noise from the fan assembly 10.

In the above example, the fan assembly is used to cool a room. The phase change material is then warmed and melts in cooling mode, and cools and solidifies in regeneration mode. In an alternative example, the fan assembly may be used to heat the room. The phase change material is then cooled and solidifies in a heating mode, and warmed and melts in regeneration mode. In this alternative example, the phase change material may have a melting point below the ambient temperature of the room, e.g. a melting point of 0 °C, such that the phase change material transitions from a liquid to a solid state in heating mode, and vice versa in regeneration mode. Again, in so doing, advantage may be taken of the latent heat capacity of the phase change material to store and subsequently release relatively large amounts of heat for a given temperature range. In the example described above, the user must first remove one of the filter assemblies in order to access and remove the tray. Figure 9 illustrates an alternative example in which the tray may be removed without having to first remove a filter assembly. The condensation collector of Figure 9 comprises a tray 110 which comprises a further seal 112 which extends around an outside of the tray 110 and is for sealing the tray 110 against the main body 15. The tray 110 is located within a slot 114 which extends beneath the filter assemblies 18,19 and second heat exchanger 49 and has an opening accessible from the outside of the main body 15. As a result, the tray 110 is removable from the main body 15 independently of the filter assemblies 18,19. Therefore, by providing an independently removable tray 110, the user is not required to unnecessarily remove the filter assemblies 18,19 to remove the tray 110. This may improve the ease of use of the fan assembly 10. Additionally, the condensation collector does not comprise a bottle. Instead, the bottle is omitted and the tray 110 of Figure 9 is deeper than the tray 77 of Figure 2. As a result, the tray 110 is capable of capturing a larger amount of condensate. Omitting the bottle may provide a simpler arrangement for the condensation collector.

Although described above in connection with a fan assembly, the refrigeration system and/or the particular packaging of the components may be used in other products, such as a ducted portable air conditioning device or a dehumidifier.

In the above examples, the thermal store surrounds the compressor of the refrigeration system of the product. In other examples, the thermal store may surround an alternative component of the product. For example, where the product comprises an airflow generator or other turbomachine, the thermal store may surround the turbomachine. Accordingly, in a more general sense, the product may be said to comprise a component and a thermal store, and the thermal store may be said to surround at least part of the component to absorb noise generated by the component.

In the above examples, the airflow generator 20 is operable to generate an airflow through the fan assembly 10 having a maximum flow rate of 25 L/s. In other examples, the airflow generated by the air generator 20 may have a different maximum flow rate. However, by having an airflow of at least 20 L/s, the fan assembly 10 may provide effective cooling of a user and/or heating of a relatively large volume, such as a room.

The above examples are to be understood as illustrative examples of the invention. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.