Thermal storage unit

Abstract

The present disclosure relates to a thermal storage unit (TSU) that is configured to be mounted in proximity to a radiator, the TSU comprising a casing and a phase change material (PCM) located inside the casing that is configured to absorb and store thermal energy from the radiator when the radiator is being used to heat an environment in which it is located, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off.

Description

[0001] THERMAL STORAGE UNIT

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to a thermal storage unit, and to a method of heating an environment using a thermal storage unit.

[0004] BACKGROUND OF THE INVENTION

[0005] Radiators are commonly used to heat rooms in buildings. Conventional radiators are able to provide thermal energy to the environment in which they are located while they are switched on (for example while being supplied with heated fluid by a central heating system in the case of fluid-filled radiators or while one or more heating elements of the radiator are being supplied with electrical power in the case of electric radiators). However, conventional radiators generally cool down and stop providing effective heating to their environment soon after being switched off. It is therefore often necessary for radiators to remain on for a large portion of the day in order to maintain rooms within a desired temperature range, or for rooms to be left unheated for extended periods of time in order to reduce heating costs and power consumption.

[0006] Conventional radiators are typically mounted on or close to walls. Mounting a radiator on or close to a wall reduces the extent to which the radiator protrudes into the room in which it is located. However, mounting a radiator on or close to a wall can result in a significant amount of the thermal energy that is emitted by the radiator being lost through the wall, thereby reducing the efficiency with which the radiator is able to heat the room in which it is located. This can be a particular problem for radiators that are mounted on or close to exterior walls, especially exterior walls that are poorly insulated. The location of a radiator on or close to a wall can also result in the room being heated unevenly.

[0007] Central heating systems that supply heated fluid to radiators may be provided with a large capacity tank in the boiler room in order to increase the quantity of heating fluid that is contained within the central heating system. By increasing the quantity of heating fluid within a central heating system it is possible to extend the period of time during which the radiators that are connected to the central heating system are able to heat the rooms in which they are located after the central heating system has stopped providing thermal energy to the heating fluid as the larger quantity of heating fluid will take longer to cool down. Central heating systems may also be provided with a thermal storage unit in the boiler room that is configured to absorb and store thermal energy from the heating fluid when the heating fluid is being heated and to return the stored thermal energy to the heating fluid after the heating fluid has stopped being heated in order to extend the period of time during which the radiators that are connected to the central heating system are able to heat the rooms in which they are located. However, central heating systems including a large capacity tank or thermal storage unit are complex and expensive to install, are not able to provide targeted heating to individual radiators or rooms, require heating fluid to continue to be pumped to radiators after the central heating system has stopped providing thermal energy to the heating fluid, and continue to suffer from heat loss through their connecting pipes after the central heating system has stopped providing thermal energy to the heating fluid.

[0008] The present invention aims to address disadvantages of known heating systems.

[0009] SUMMARY OF THE INVENTION

[0010] According to a first aspect of the invention, there is provided a thermal storage unit (TSU) that is configured to be mounted in proximity to a radiator, the TSU comprising a casing and a phase change material (PCM) located inside the casing. The PCM may be configured to absorb and store thermal energy from the radiator when the radiator is being used to heat an environment in which it is located, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off.

[0011] The TSU preferably does not include any independent heat source, and is instead simply configured to absorb, store and return thermal energy from a radiator.

[0012] The TSU of the present invention advantageously enables thermal energy to continue to be delivered to the environment after the radiator has been switched off as the TSU can continue to provide thermal energy to the radiator and / or the environment after the radiator has been switched off and begun to cool down. The TSU can therefore be used to extend the time period during which thermal energy is delivered to the environment and / or to reduce the duration during which the radiator itself must be powered in order to heat the environment. The TSU of the present invention can also be used for peak shaving or load shedding as the TSU can be charged with thermal energy from a radiator outside of peak times when energy demand and costs are lower and subsequently release the stored thermal energy during peak hours when energy demand and costs are higher even if the radiator that was used to charge it is switched off. The TSU can, for example, be charged during the night and then release thermal energy during the morning, thereby delaying the point at which the radiator that was used to charge it needs to be switched on in the morning. By absorbing thermal energy from the radiator when the radiator is switched on the TSU is also able to limit temperature rises in the environment when the radiator is switched on, thereby enabling the environment to be maintained at a more comfortable temperature.

[0013] The TSU may be configured to be mounted between a radiator and a wall located behind the radiator. If the TSU is mounted between a radiator and a wall then the TSU is also able to reduce heat loss from the radiator as the TSU is able to absorb and store excess thermal energy that would otherwise be lost through the wall and return the stored thermal energy to the radiator and / or to the environment.

[0014] The TSU may comprise a forced convection system including at least one air channel that extends through the TSU and at least one fan or blower unit that is configured to move air through the air channel. The inclusion of a forced convection system allows the TSU to transfer thermal energy to the environment at a significantly faster rate than would be possible by natural convection and radiation alone, thereby providing improved heating performance. The inclusion of a forced convection system may also allow a user of the TSU to control the rate at which thermal energy is transferred from the TSU to the environment, thereby allowing greater control of the temperature in a room that is being heated by the TSU.

[0015] The forced convection system preferably includes at least two air channels. In a preferred embodiment the forced convection system includes three air channels. The or each air channel may extend between a first opening and a second opening. The first opening may be provided at the bottom of the TSU, optionally in a bottom panel of the casing, and the second opening may be provided at the top of the TSU, optionally in a top panel of the casing. The first opening may be an inlet and the second opening may be an outlet of the air channel. However, it will be appreciated that the roles of the first and second openings may be reversed if the direction of air flow through the air channel is reversed.

[0016] The TSU may be configured to direct air exiting the air channel(s) outwardly therefrom in a direction angled away from a front face of the TSU, optionally in a direction substantially perpendicular to the front face of the TSU. In this case the TSU may be provided with one or more flow-redirecting hoods which are configured to direct the flow of air leaving the air channel(s) into the environment in which the TSU is located. In other embodiments the air channel(s) may include outlets that are provided in a front panel of the casing in a portion of the casing that extends beyond the radiator, for example in a portion of the casing that is located above a top of the radiator during use of the TSU.

[0017] The outlet of the or each air channel may be provided with at least one movable flowdirecting element that is configured to be moved in order to control the direction in which air exits the air channel(s).

[0018] The or each air channel may include at least one air channel fin that extends into the air channel. The air channel fin(s) may be formed of a heat conducting material, for example a metal such as aluminum. The air channel fin(s) may advantageously increase the rate at which thermal energy can be transferred from the TSU to air passing through the air channel(s). The or each air channel preferably includes at least two air channel fins. In a preferred embodiment the or each air channel includes three air channel fins.

[0019] The air channel fin(s) may include a plurality of plate-like elements that are arranged parallel to each other, and may extend across a width of the air channel. The air channel fin(s) may have an at least substantially constant cross-sectional shape along a direction aligned with a height of the casing, and may extend along at least substantially the entire length(s) of the air channel(s), for example along at least 80% of the length(s) of the air channel(s).

[0020] The fan or blower unit(s) may be located at the bottom of the TSU, in which case they may be mounted to the bottom panel of the casing. Alternatively, the fan or blower unit(s) may be located at the top of the TSU, in which case they may be mounted to the top panel of the casing. The fan or blower unit(s) may be operable at a single speed, and may be configured to move air through the air channels in a single direction only, for example in an upward direction. Alternatively, the fan or blower unit(s) may be operable at different speeds and / or may be selectively operable to move air through the air channels in either direction. The fan or blower unit(s) may optionally be located inside a cover, which may be mounted to the casing.

[0021] The TSU may include at least one user-operable interface element that is configured to control operation of the fan or blower unit(s). The TSU may include a single interface element that is configured to control operation of multiple fan or blower unit(s) together, or alternatively multiple interface elements that are configured to control operation of respective fan or blower units individually. The interface element(s) may comprise one or more buttons, switches, knobs, sliders or touchscreens. In some embodiments the interface element(s) may be configured to control the operating speed and / or the direction of operation of the fan or blower unit(s) as well as switching the fan or blower unit(s) on and off.

[0022] Alternatively, or in addition, the fan or blower unit(s) may be configured to be controlled remotely, for example using a remote controller or a mobile device including an app for controlling operation of the TSU.

[0023] The TSU may comprise at least one PCM-engaging fin that is located inside the casing and in contact with the PCM. The PCM-engaging fin(s) may be formed of a heat conducting material, for example a metal such as aluminum. The PCM-engaging fin(s) may advantageously enhance heat diffusion within the PCM and increase the rate at which thermal energy can be transferred to the PCM when the TSU is being charged by a radiator and the rate at which thermal energy can be transferred from the PCM when the TSU returns the stored thermal energy to the radiator and / or to the environment.

[0024] The PCM-engaging fin(s) may be connected to a first wall or front wall of the casing. The first wall or front wall of the casing may be a wall that is configured to face towards a radiator during use of the TSU. Connecting the PCM-engaging fin(s) to the front wall of the casing increases the rate at which thermal energy can be transferred to the PCM while the TSU is being heated by a radiator, and the rate at which thermal energy can be returned from the PCM to the radiator after the radiator has been switched off. However, the PCM-engaging fin(s) are preferably not connected to and preferably do not engage the remaining external walls of the casing, particularly a second wall or rear wall of the casing opposite the first wall or front wall, as this would increase the rate of heat loss from the TSU.

[0025] The PCM-engaging fin(s) may be spaced apart from a second wall or rear wall of the casing opposite the first wall or front wall. The second wall or rear wall of the casing may be a wall that is configured to face away from a radiator during use of the TSU. Spacing the PCM-engaging fin(s) apart from the rear wall of the casing increases the ability of the PCM to flow within the casing when in a liquid state, which enhances heat diffusion within the PCM and increases the rate and uniformity of thermal energy transfer to and from the PCM.

[0026] The PCM-engaging fin(s) may be provided with perforations. Providing the PCM- engaging fin(s) with perforations enables the PCM to move through the PCM-engaging fin(s) when in a liquid state, thereby further enhancing the ability of the PCM to flow within the casing. The perforations may comprise discrete apertures, for example round or circular holes, and may have a width or diameter in the range 2-1 Omm.

[0027] The PCM-engaging fin(s) may have an at least substantially constant cross-sectional shape along a direction aligned with a height of the casing, and may extend at least substantially through the entire height of the casing, for example through at least 80% of the height of the casing. However, the PCM-engaging fin(s) may be at least slightly spaced apart from top and / or bottom walls of the casing in order to increase the ability of the PCM to flow within the casing when in a liquid state and reduce the rate of heart loss through the top and bottom walls of the casing.

[0028] The PCM-engaging fin(s) may have a corrugated or waveform shape when viewed from above. Alternatively, the PCM-engaging fins may each include a plate-like main body and at least one plate-like projecting portion that projects outwardly from the main body.

[0029] Where the TSU includes a forced convection system including a plurality of air channels in addition to a plurality of PCM-engaging fins, the PCM-engaging fins may be located between the air channels, with at least one PCM-engaging fin being present between each pair of adjacent air channels.

[0030] The TSU may be configured to be mounted directly to a radiator. Alternatively, the TSU may be configured to be mounted to a wall located in proximity to a radiator in order to place the TSU in proximity to the radiator.

[0031] The TSU may be configured to be readily mounted to and detached from a radiator or wall by an end user. The TSU is preferably configured to be mounted to and detached from a radiator or wall by an end user without the need to install or remove any bolts or other fasteners. Configuring the TSU to be readily mounted to and detached from a radiator or wall facilitates installation of the TSU, and also enables the TSU to be charged with thermal energy by a radiator and subsequently moved to a different location away from the radiator in order to release the stored thermal energy at a different location. For example, the TSU can be mounted in proximity to a radiator in a first room in order to absorb thermal energy from the radiator while the radiator is switched on, and may then be moved to a different location within the first room in order to release energy into the first room more effectively, or moved into a second room different to the first room in order to release thermal energy in a different room. Alternatively, the TSU may be configured to be semi-permanently mounted to a radiator or wall, for example by a mounting system including one or more bolts or clamps that are not intended to allow rapid removal of the TSU by an end user. The TSU may be configured to be mounted to a radiator or wall by lowering the TSU into position relative to the radiator or wall, for example into a gap formed between the radiator and the wall, and / or to be detached from a radiator or wall by lifting the TSU away from the radiator or wall, for example by lifting the TSU in a vertical direction.

[0032] The TSU may comprise at least one and preferably a plurality of mounting elements that are configured to enable the TSU to be mounted to a radiator or wall. The mounting elements may comprise one or more hooks, loops, brackets or clamps. The mounting elements may be configured to engage the main body of a radiator, in which case the TSU may be mounted directly to a radiator without the need to provide corresponding mounting elements on the radiator or on a wall located in proximity to the radiator. Alternatively the mounting elements of the TSU may be configured to engage one or more corresponding mounting elements such as hooks, loops, brackets or clamps provided on a radiator or wall.

[0033] The TSU may comprise at least one aperture that extends through the thickness of the TSU and is configured to receive a mounting bracket of a radiator therein. The inclusion of mounting bracket-receiving apertures may enable the TSU to extend across a gap between a radiator and a wall to which the radiator is mounted without being constrained by the presence of any brackets that are used to mount the radiator to the wall. In one embodiment the TSU may comprise two mounting bracket-receiving apertures for receiving two radiator mounting brackets therein. However, a larger number of mounting bracket-receiving apertures may be selected depending on the number of mounting brackets that are used to mount a particular radiator to a wall.

[0034] The or each mounting bracket-receiving aperture may comprise an elongate slot that extends in a direction aligned with a height of the casing from an open lower end provided at a bottom of the casing. The open lower ends of the mounting bracketreceiving apertures may enable the TSU to be lowered into a gap between a radiator and a wall to which the radiator is mounted around mounting brackets that are used to mount the radiator to the wall.

[0035] The TSU may be configured to be mounted in proximity to a radiator by engagement of the mounting bracket-receiving aperture(s) with one or more brackets that are used to mount the radiator to a wall. For example, the or each mounting bracket-receiving aperture may have a closed upper end that is configured to engage an upper portion of a radiator mounting bracket. In this case it may not be necessary for the TSU to be provided with any additional mounting elements for mounting the TSU to a radiator or wall, and the weight of the TSU may be supported by engagement of the mounting bracket-receiving aperture(s) with one or more radiator mounting brackets. However, in other embodiments a TSU including one or more mounting bracket-receiving apertures may be mounted to a radiator or wall by one or more mounting elements that are provided separately to the mounting bracket-receiving aperture(s). In this case the mounting bracket-receiving aperture(s) may serve only to accommodate one or more radiator mounting brackets, and may not be used to support the weight of the TSU.

[0036] The or each mounting bracket-receiving aperture may be provided with at least one pad on an inner surface thereof. The pads may be configured to provide cushioning between the TSU and one or more radiator mounting brackets, to reduce or prevent lateral movement of the TSU relative to the radiator and / or to provide enhanced grip between the TSU and the radiator mounting brackets in order to provide increased resistance to dismounting of the TSU from the radiator mounting brackets. The pads may be formed of a resiliently compressible material and / or may have a high-friction surface.

[0037] TSUs according to the present invention may be manufactured with different configurations of mounting bracket-receiving apertures in order to fit radiators with common mounting bracket configurations. Alternatively, a TSU may be manufactured to order with a specific configuration of mounting bracket-receiving apertures in order to match the mounting bracket configuration of a specific radiator.

[0038] The TSU may comprise at least one handle. Providing the TSU with at least one handle facilitates movement of the TSU by an end user, especially when the TSU is at an elevated temperature after having been charged with thermal energy by a radiator. The casing may be formed of a metal such as aluminium. The use of aluminium for the casing has been found to provide a sturdy casing that allows thermal energy to be transferred to and from the PCM located therein rapidly while minimising the weight of the TSU.

[0039] The casing may be sealed to define a sealed internal chamber in which the PCM is located. The casing may include an air gap to account for changes in the volume of the PCM during use of the TSU.

[0040] The casing may be generally cuboidal in shape, and may have a thickness that is significantly lower than its height and width. For example, the casing may have a thickness that is less than 10% of its height and / or width or less than 5% of its height and / or width. Forming the casing with a cuboidal shape having a thickness that is significantly lower than its height and width may facilitate placement of the TSU in a gap between a radiator and a wall.

[0041] The TSU may comprise a front face with a corrugated shape. The corrugated shape of the front face of the TSU may match the shape of the rear face of a radiator with which the TSU may be used. Forming the TSU with a front face that matches the shape of the rear face of a radiator with which the TSU is used enhances the efficiency of the transfer of thermal energy between the radiator and the TSU. Alternatively, the front face of the TSU may be at least substantially planar.

[0042] The casing may have a thickness of at least 10mm and / or no more than 30mm. Forming the casing with a thickness of at least 10mm enables the TSU to contain a sufficient quantity of PCM to provide effective heating to its environment for a significant period of time after the radiator that was used to charge it has been switched off. Forming the casing with a thickness of no more than 30mm maximises the compatibility of the TSU with existing radiators, which are often mounted in close proximity to a wall. In general, increasing the thickness of the casing will increase the amount of PCM that can be located inside a TSU of given height and width dimensions, thereby increasing the thermal capacity of the TSU and extending the time period during which the TSU will be able to provide effective heating to its environment. It will be appreciated that larger thicknesses may be used in other applications depending on the space that is available between a radiator and a wall.

[0043] The TSU may include at least 3kg of PCM and / or no more than 15kg of PCM. Including at least 3kg of PCM in the TSU ensures that the TSU is able to provide effective heating to its environment for a significant period of time after the radiator that was used to charge it has been switched off. Including no more than 15kg of PCM in the TSU limits the stress that the TSU applies to a radiator or wall to which it is mounted and facilitates handling of the TSU by an end user.

[0044] The TSU may include a metal foam such as copper foam that is located inside the casing and in contact with the PCM. The metal foam may be configured to allow the PCM to flow therethrough when in a liquid state. The inclusion of a metal foam such as coper foam inside the casing together with the PCM may advantageously increase the rate at which thermal energy can be transferred to and from the PCM and enhance heat diffusion within the PCM.

[0045] The PCM may be a paraffin based PCM. However, other types of organic and inorganic PCMs may also be used.

[0046] The PCM is intended to be melted and solidified during use of the of the TSU. The PCM should therefore have a melting point that is above the normal ambient temperature of the environment in which it is used but below the operating surface temperature of the radiator with which it is used. The PCM preferably has a melting point that is close to but slightly below the operating surface temperature of the radiator with which it is used, for example within 5°C or within 2.5°C of the operating surface temperature of the radiator. Selecting a PCM with a melting point that is close to but slightly below the operating surface temperature of the radiator maximises the heating performance of the TSU while still enabling the PCM to be fully melted by the radiator during use. Radiators commonly have an operating surface temperature of around 55-65°C. The PCM may have a melting point of at least 40°C and / or no more than 65°C. In a preferred example the PCM may have a melting point in the range 50- 63°C, optionally in the range 55-59°C. PCMs with a melting point in this range have been found to provide optimum heating performance when used in combination with many standard radiators, although PCMs with other melting points may also be used in other embodiments, especially in TSUs that are designed to be used in combination with radiators having higher or lower operating surface temperatures.

[0047] The TSU may comprise a layer of insulation. The layer of insulation is preferably provided at least on the rear face of the TSU, and may also be provided on side, top and bottom faces of the TSU. Providing the TSU with a layer of insulation especially on its rear face reduces heat loss from the TSU. However, the layer of insulation preferably does not extend across the front face of the TSU in order to avoid interrupting the transfer of thermal energy between the TSU and a radiator.

[0048] The layer of insulation may, for example, comprise polyisocyanurate (PIR) or a vacuum panel, may have a thickness in the range 2-5mm, and may be provided on the exterior of the casing or integrated into the rear wall of the casing. Providing the layer of insulation with a thickness in the range 2-5mm ensures adequate insulation performance without significantly reducing the interior volume of the casing that can be filled with PCM.

[0049] The TSU may comprise at least one temperature sensor that is configured to sense a temperature of the PCM. The temperature sensor may be provided on a rear wall of the casing, and may be located towards the bottom of the casing, for example in the bottom 20% of the casing. If the TSU comprises PCM-engaging fins then the temperature sensor may be located between adjacent PCM-engaging fins (instead of being located directly adjacent to one of the PCM-engaging fins). Locating the temperature sensor towards the rear of the casing, towards the bottom of the casing and away from any PCM-engaging fins ensures that the temperature sensor will measure the temperature of the PCM at one of the cooler points in the TSU, thereby avoiding overestimating the temperature of the PCM.

[0050] The TSU may comprise an output element that is configured to provide an indication of the temperature of the PCM as determined by the temperature sensor and / or to provide a notification when the temperature of the PCM has reached a predetermined value. The output element may, for example, comprise a digital display, a screen or a series of lights that are configured to display the temperature of the PCM as determined by the temperature sensor; a light that is configured to turn on when the temperature of the PCM has reached a predetermined value; a screen that is configured to display an icon or message when the temperature of the PCM has reached a predetermined value, or a speaker that is configured to play a message or tone when the PCM has reached a predetermined value. Where the TSU comprises a user-operable interface element that is configured to control operation of one or more fan or blower units the output element may optionally be integrated with the user- operable interface element. For example, a single touchscreen may be used to control operation of one or more fan or blower units and to display information related to the temperature or charge state of the TSU.

[0051] The predetermined value may be a temperature that is slightly lower (for example 1 -2 degrees lower) than the operating temperature of the radiator and / or a temperature that is slightly higher (for example 1-2 degrees higher) than the melting point of the PCM. The TSU may be considered to be fully charged when the PCM has reached the predetermined value.

[0052] The TSU may comprise a communication module that is configured to output a signal representative of the temperature of the PCM as determined by the temperature sensor and / or to output a signal representative of whether or not the temperature of the PCM has reached a predetermined value to a device external to the TSU. The communication module may be a wireless communication module that is configured to output signals wirelessly, or a wired communication module that is configured to output signals via a physical wire. The communication module may be configured to output signals to a controller, a switch or a mobile device including an app that is configured to display information related to the temperature or charge state of the TSU and / or to turn one or more radiators on and / or off in dependence on the temperature of the PCM.

[0053] According to a further aspect of the invention, there is provided an apparatus for providing thermal energy to an environment, for example a room inside a building, the apparatus comprising a radiator and a TSU according to the first aspect of the invention. The TSU may be mounted in proximity to the radiator, and may be configured to absorb and store thermal energy from the radiator when the radiator is being used to heat the environment, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off.

[0054] The radiator may be a fluid-filled radiator that is configured to be supplied with heated fluid by a central heating system. Alternatively, the radiator may be an electric radiator that includes at least one electric heating element.

[0055] The TSU may be located outside an external contour of the radiator.

[0056] The radiator may be located in proximity to a wall, and may optionally be mounted to the wall. The TSU may be located in a gap formed between the radiator and the wall.

[0057] The TSU may be mounted to the radiator or wall by one or more mounting elements such as hooks, loops, brackets or clamps and / or by engagement of one or more radiator mounting bracket-receiving apertures with one or more brackets that are used to mount the radiator to the wall, as described above in connection with the first aspect of the invention. Alternatively, the TSU may be held in position relative to the radiator by being received in a holder that is mounted to the rear face of the radiator or to the wall.

[0058] The front face of the TSU is preferably in contact with the rear face of the radiator in order to maximise the rate at which thermal energy can be transferred between the TSU and the radiator and reduce heat loss between the TSU and the radiator. However, it will be appreciated that the front face of the TSU may alternatively be slightly spaced apart from the rear face of the radiator, provided that the front face of the TSU and the rear face of the radiator are sufficiently close together to enable effective heat transfer between the TSU and the radiator. In other embodiments the front face of the TSU may, for example, be located within 10mm or within 5mm of the rear face of the radiator.

[0059] The radiator may be a panel type radiator, optionally with corrugated front and rear surfaces, and the front face of the TSU may match the shape of a rear face of the radiator. The TSU may have a height that is greater than the height of the radiator and / or a width that is greater than the width of the radiator. Forming the TSU with height and / or width dimensions that are greater than those of the radiator may allow a larger amount of PCM to be contained in the TSU for use with a radiator of a given size, thereby increasing the thermal capacity of the TSU and extending the time period during which the TSU will be able to provide effective heating to its environment. Forming the TSU with height and / or width dimensions that are greater than those of the radiator may also increase the efficiency with which thermal energy can be absorbed by the TSU when the radiator is being used to heat the environment and the efficiency with which thermal energy can be returned to the radiator and / or to the environment after the radiator has been switched off. The TSU may, for example, have height and / or width dimensions that are at least 25% greater than those of the radiator. In other embodiments the TSU may be significantly larger, for example having height and / or width dimensions that are at least twice those of the radiator.

[0060] The TSU may be supplied separately to the radiator and retrofitted to the radiator as an aftermarket accessory. In this way the TSU may be used to improve heating performance and reduce heating bills in a building that is already fitted with standard radiators even if the existing radiators in the building where not originally designed or intended to be used in combination with a TSU.

[0061] According to a further aspect of the invention, there is provided a method of heating an environment, for example a room inside a building, the method comprising: a) mounting a TSU according to the first aspect of the invention in proximity to a radiator; b) using the radiator to heat the environment; c) absorbing thermal energy from the radiator into the TSU while the radiator is being used to heat the environment, and storing the thermal energy in the PCM; d) returning the stored thermal energy from the TSU to the radiator and / or to the environment.

[0062] The step of using the radiator to heat to the environment may be performed by supplying heated fluid to the radiator, or alternatively by supplying electrical power to one or more electric heating elements of the radiator in order to increase the temperature of the radiator above the ambient temperature of the environment, and may be performed during off-peak times when energy demand and costs are lower.

[0063] The method may further comprise a step of switching the radiator off or reducing the temperature of the radiator between the step of absorbing thermal energy from the radiator into the TSU and the step of returning the stored thermal energy from the TSU to the radiator and / or to the environment.

[0064] The step of switching the radiator off or reducing the temperature of the radiator may be performed by ceasing or reducing the supply of heated fluid to the radiator, or alternatively by ceasing or reducing the supply of electrical power to one or more electric heating elements of the radiator, and may be performed during peak times when energy costs are higher.

[0065] The step of absorbing thermal energy from the radiator into the TSU may comprise melting the PCM from a solid state to a liquid state, preferably completely melting the PCM such that at least substantially all of the PCM is melted. The step of returning the stored thermal energy from the TSU to the radiator and / or to the environment may comprise solidifying the PCM from a liquid state to a solid state, optionally completely solidifying the PCM such that at least substantially all of the PCM is solidified.

[0066] The method may further comprise a step of moving the TSU to a different location after the step of absorbing thermal energy from the radiator into the TSU in order to enable thermal energy to be released from the TSU at a different location to the radiator.

[0067] The radiator may be located inside a room in a building. The step of moving the TSU to a different location may comprise moving the radiator to a different location within the room in which the radiator is located, or alternatively moving the TSU to a location outside the room in which the radiator is located.

[0068] According to a further aspect of the invention, there is provided a method of modifying a radiator, the method comprising a step of mounting a TSU according to the first aspect of the invention in proximity to the radiator. The radiator may be a pre-existing radiator that was not originally designed or intended to be used in combination with a TSU, and the TSU may be mounted in proximity to the radiator as an aftermarket accessory. The step of mounting the TSU in proximity to the radiator may, for example, comprise lowering the TSU into a gap formed between the radiator and a wall.

[0069] The TSU of the present invention is intended primarily to be used in domestic applications, for example in houses and flats, but may also be used in other environments including radiators.

[0070] It will be appreciated that that various features that are described above in connection with the various aspects of the present invention may be used together in any suitable combination unless they are incompatible with each other.

[0071] BRIEF DESCRIPTION OF DRAWINGS

[0072] Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0073] Figures 1 to 3 schematically illustrate front, side and top views of a thermal storage unit according to one possible embodiment of the present invention;

[0074] Figure 4 schematically illustrates a cross-section view of the thermal storage unit;

[0075] Figure 5 schematically illustrates perforations in a fin of the thermal storage unit;

[0076] Figure 6 schematically illustrates a cross-section view of the thermal storage unit according to second embodiment of the present invention;

[0077] Figure 7 schematically illustrates the thermal storage unit mounted to a radiator;

[0078] Figure 8 schematically illustrates an alternative mounting system for the thermal storage unit; Figure 9 schematically illustrates a thermal storage unit including mounting bracketreceiving apertures for accommodating brackets that are used to mount a radiator to a wall;

[0079] Figure 10 schematically illustrates an alternative shape for a front surface of the thermal storage unit.

[0080] DETAILED DESCRIPTION OF EMBODIMENTS

[0081] Figures 1 to 4 schematically illustrate a thermal storage unit (TSU) 1 according to one possible embodiment of the present invention. Figure 1 illustrates a front view, Figure 2 illustrates a side view, Figure 3 illustrates a top view, and Figure 4 illustrates a crosssection view taken in a plane perpendicular to a hight direction of the TSU 1 . The TSU 1 is configured to be mounted to a radiator, to absorb and store thermal energy from the radiator when the radiator is being used to heat an environment in which it is located, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off, as described in more detail below.

[0082] As shown in Figures 1 to 4, the TSU 1 is generally cuboidal in shape. The TSU 1 includes a first face or front face 1 a that is configured to face towards a radiator and an opposing second face or rear face 1 b that is configured to face away from the radiator during use of the TSU 1 . The TSU 1 also includes a third face or top face 1 c, a fourth face or bottom face 1 d, and a pair of opposing fifth and sixth faces or side faces 1 e, 1f, each of which extends between the front and rear faces 1a, 1 b. The TSU 1 has a thickness T that extends between the front and rear faces 1 a, 1 b, a height H that extends between the top and bottom faces 1 c, 1 d, and a width W that extends between the side faces 1 e, 1f.

[0083] The TSU 1 comprises a cuboidal aluminium casing 2 including a first panel or front panel 2a, a second panel or rear panel 2b, a third panel or top panel 2c, a fourth panel or bottom panel 2d, and fifth and sixth panels or side panels 2e, 2f, which define the front, rear, top, bottom and side faces of the TSU 1 . The casing 2 defines a sealed internal chamber 3 that contains a phase change material (PCM) 4. The PCM 4 may be a paraffin based PCM, for example Rubitherm RT55 or Rubitherm RT54HC, and may have a melting point in the range 55-59°C. The PCM 4 fills a majority of the internal chamber 3 of the TSU 1 . However, the internal chamber 3 also includes an air gap to account for changes in the volume of the PCM 4 during use of the TSU 1 . The casing 2 has a width W of approximately 970mm, a height H of approximately 570mm, a thickness T of approximately 20mm, and contains approximately 8kg of PCM. However, it will be appreciated that other dimensions and other quantities of PCM may be used in other embodiments.

[0084] The TSU 1 also comprises a forced convection system 5 for increasing the rate at which thermal energy can be transferred from the TSU 1 to its environment. The forced convection system 5 includes a plurality of air channels 6 that extend through the TSU 1 . Each of the air channels 6 is formed by an aluminium tube 7 that extends in a direction aligned with the height H of the TSU 1 between the top panel 2c and the bottom panel 2d of the casing 2. The top panel 2c and the bottom panel 2d of the casing 2 include apertures that are aligned with the tubes 7 in order to provide each of the air channels 6 with an inlet 6a in the bottom face 1 d of the TSU 1 and an outlet 6b in the top face 1 c of the TSU 1 . Each of the tubes 7 is connected to the front panel 2a of the casing 2, but is spaced apart from the rear panel 2b of the casing 2 in order to allow the PCM 4 to flow between the air channels 6 and the rear panel 2b of the casing 2 while in a liquid state.

[0085] Each of the air channels 6 is provided with a plurality of air channel fins 6c that extend across the air channel 6. The air channel fins 6c are formed of a heat conducting material such as aluminium, and are formed as parallel, plate-like elements that extend between opposing sidewalls of the tubes 7 over at least a majority of the lengths of the air channels 6. The air channel fins 6c increase the rate at which thermal energy can be transferred from the TSU 1 to air passing through the air channels 6.

[0086] Each of the air channels 6 is also provided with a fan or blower unit 8 that is attached to the bottom panel 2d of the casing 2 adjacent the inlet 6a of the air channel 6 and configured to move air through the air channels 6 when switched on. Each of the fan or blower units 8 comprises a fan or blower 8a for moving air through its respective air channel 6, a battery 8b for providing power to the fan or blower 8a, and a user-operable interface element 8c such as a button, switch, knob, slider or touchscreen for controlling operation of the fan or blower 8a. In other embodiments the TSU 1 may include a common battery for providing power to multiple fan or blower units 8 and / or a common interface element for controlling operation of multiple fan or blower units 8 instead of including separate batteries and interface elements for each individual fan or blower unit 8. The interface elements 8c may optionally be configured to control the operating speed and / or the direction operation of the fan or blower units 8 as well as switching the fan or blower units 8 on and off. The fan or blower units 8 may also be configured to be controlled remotely, for example using a remote controller or a mobile device including an app for controlling operation of the TSU 1 .

[0087] The outlets 6b of the air channels 6 may also be provided with movable flow-directing elements that are configured to be moved in order to control the direction in which air exits the air channels 6. The movable flow-directing elements may be similar to those found on the outlets of air conditioning systems in automobiles. The movable flowdirecting elements may be manually movable, or may be movable by motors, which may be controlled via a user-operable interface element (optionally the same interface element that is used to control the motors), by a remote controller or by a mobile device including an app for controlling operation of the TSU 1 .

[0088] The TSU 1 also comprises a plurality of PCM-engaging fins 10 that are located inside the internal chamber 3 defined by the casing 2 and in contact with the casing 2 and the PCM 4 for increasing the rate at which thermal energy can be transferred to and from the PCM 4. The PCM-engaging fins 10 are located between the air channels 5, and are formed of a heat conducting material such as aluminium.

[0089] As shown in Figure 4, the PCM-engaging fins 10 have a corrugated or waveform shape when viewed from above. The PCM-engaging fins 10 have an at least substantially constant cross-sectional shape along the height direction H of the TSU 1 , and extend at least substantially through the entire height H of the casing 2. The portions of the PCM-engaging fins 10 closest to the front panel 2a of the casing 2 are connected to the front panel 2a in order to improve the efficiency of heat transfer between the PCM 4 and the front panel 2a of the casing 2. However, the PCM- engaging fins 10 are spaced apart from the rear panel 2b of the casing 2 in order to allow the PCM 4 to flow between the PCM-engaging fins 10 and the rear panel 2b of the casing 2 while in a liquid state.

[0090] As shown in Figure 5, the PCM-engaging fins 10 are also provided with perforations 10’ in the form of circular holes with a diameter of approximately 3mm in order to enable the PCM 4 to flow through the PCM-engaging fins 10 when in a liquid state.

[0091] Figure 6 illustrates a cross-section view of an alternative embodiment of the present invention including a different PCM-engaging fin configuration. In the embodiment shown in Figure 6 each of the waveform PCM-engaging fins 10 as shown in Figure 4 is replaced by a plurality of discrete PCM-engaging fins 11 , each of which includes a plate-like main body 11 a that is connected to the front panel 2a of the casing and extends outwardly therefrom in a direction towards the rear panel 2b of the casing 2, and a plurality of plate-like projecting portions 11 b that extend outwardly from the main body 11 a in directions perpendicular thereto.

[0092] As with the PCM engaging fins 10 shown in Figure 4, the PCM-engaging fins 11 shown in Figure 6 also have an at least substantially constant cross-sectional shape along the height direction H of the TSU 1 , extend at least substantially through the entire height H of the casing 2, are spaced apart from the rear panel 2b of the casing 2 in order to allow the PCM 4 to flow between the PCM-engaging fins 10 and the rear panel 2b of the casing 2 while in a liquid state, and are provided with perforations in order to enable the PCM 4 to flow through the PCM-engaging fins 11 when in a liquid state.

[0093] The TSU 1 also comprises a layer of insulation material 12 that extends across the rear face 1 b and the side faces 1 e, 1f of the TSU 1 in order to reduce the rate at which thermal energy is able to leave the TSU 1 via the rear face 1 b and the side faces 1 e, 1f. The insulation material 12 comprises polyisocyanurate (PIR), has a thickness of approximately 4mm, and is provided on the exterior of the casing 2. The TSU 1 also comprises a pair of handles 14 that are mounted to the top panel 2c of the casing 2 and extend upwardly from the top face 1 c of the TSU 1 . The handles

[0094] 14 are configured to facilitate movement of the TSU 1 , as described in more detail below.

[0095] The TSU 1 also comprises a pair of hooks 15 that are mounted to the top panel 2c of the casing 2 and extend outwardly in front of the front face 1 a of the TSU 1 . The hooks

[0096] 15 are configured to enable the TSU 1 to be mounted to a radiator, as described in more detail below.

[0097] The TSU 1 also comprises a temperature sensor 30 in the form of a thermocouple that is mounted to the interior surface of the rear panel 2b of the casing 2 towards the bottom of the casing 2 at the location of one of the air channels 6 (between a pair of adjacent PCM-engaging fins 10). The temperature sensor 30 is in contact with the PCM 4, and is configured to output signals representative of the temperature of the PCM 4 as measured by the temperature sensor 30. The temperature sensor 30 is connected to an output element in the form of an indicator light 31 that is configured to switch on when the temperature of the PCM 4 reaches a predetermined temperature, which may be set to be slightly lower than the operating temperature of the radiator with which the TSU 1 is to be used and / or slightly higher than the melting point of the PCM 4. During use of the TSU 1 , the indicator light 31 provides a visual indication of when the TSU 1 has been fully charged. The temperature sensor 30 is also connected to a wireless communication module 32 that is configured to output wireless signals representative of the temperature of the PCM 4 to an external controller or switch 33 that is configured to control operation of the radiator which the TSU 1 is used, as described in more detail below.

[0098] Figure 7 schematically illustrates the TSU 1 in use in combination with a radiator 16. The radiator 16 is a standard, pre-existing radiator to which the TSU 1 may be fitted as an aftermarket accessory. As shown in Figure 7, the radiator 16 is located in a room 17 of a building such as a house adjacent to a wall 18 of the room 17, and the TSU 1 is located outside of an external contour of the radiator 16 in a gap 19 formed between the radiator 16 and the wall 18. The TSU 1 is mounted to the radiator 16 by the hooks 15, which extend over the top surface of the radiator 16 and engage the radiator 16 in order to suspend the TSU 1 therefrom. The hooks 15 are configured to enable the TSU 1 to be mounted to the radiator 16 by simply lowering the TSU 1 into the gap 19 between the radiator 16 and the wall 18 until the hooks 15 engage the radiator 16, and to be removed from the radiator 16 by simply lifting the TSU 1 in an upward direction away from the radiator 16. The front face 1a of the TSU 1 is in direct contact with a rear face of the radiator 16 when the TSU 1 is mounted to the radiator as shown in Figure 7.

[0099] When the radiator 16 is switched on (for example by being supplied with heated fluid from a central heating system if the radiator 16 is a fluid filled radiator or by being supplied with electrical power if the radiator 16 is an electric radiator) the radiator 16 will be at an elevated temperature compared to the room 17 and will transfer thermal energy to the TSU 1 through the front panel 2a of the casing 2 as well as providing thermal energy to the room 17. At least a portion of the thermal energy that is transferred to the TSU 1 from the radiator 16 will be thermal energy that would otherwise be lost through the wall 18 if the TSU 1 was not present. As the TSU 1 absorbs thermal energy from the radiator 16, the PCM 4 located inside the TSU 1 will melt and store the absorbed thermal energy.

[0100] When the radiator 16 is subsequently turned off (for example by stopping the supply of heated fluid to the radiator 16 or stopping supplying electrical power to electric heating elements of the radiator 16) the radiator 16 will begin to cool down and the PCM 4 in the TSU 1 will remain at a higher temperature than the radiator 16 and the room 17 in which it is located. The PCM 4 in the TSU 1 will then transfer the stored thermal energy that was previously absorbed from the radiator 16 back to the radiator

[0101] 16 through the front panel 2a of the casing 2 and to the air surrounding the TSU 1 for a period of at least 2 hours. The fan or blower units 8 may also be switched on after the radiator 16 has been turned off in order to force air through the air channels 6, thereby increasing the rate at which thermal energy is transferred to the air in the room 17. In this way the TSU 1 is able to continue to provide effective heating to the room

[0102] 17 for an extended time period after the radiator 16 has been turned off, thereby extending the time period during which thermal energy can be delivered to the room 17 and / or reducing the time period during which the radiator 16 is required to be switched on. The TSU 1 , once charged with thermal energy from the radiator 16, may also be moved to a different location, either within the room 17 in which the radiator 16 is located or alternatively in a different room, in order to provide heating from a different location. In this case the hook-based mounting system 15 (which enables the TSU 1 to be detached from the radiator 16 by simply lifting the TSU 1 in an upward direction away from the radiator 16) and the handles 14 facilitate movement of the TSU 1 by an end user.

[0103] The indicator light 31 provides an indication of when the TSU 1 has been fully charged, which may be used as a prompt for a user to switch the radiator 16 off or to move the TSU 1 to a different location. The external controller or switch 33 may also be configured to switch the radiator 16 off automatically once the TSU 1 has been fully charged (for example when the PCM 4 has reached the above-mentioned predetermined temperature).

[0104] It will be appreciated that many modifications may be made to the above-described embodiments without departing from the scope of the present invention as defined in the appended claims.

[0105] For example, in the above-described embodiment the TSU 1 has height and width dimensions that at least substantially match those of the radiator 16. However, in other embodiments the TSU 1 may have a height that is greater than that of the radiator 16 and / or a width that is greater than that of the radiator 16, which may increase total heat capacity of the TSU 1 and increase the efficiency with which thermal energy can be absorbed by the TSU 1 when the radiator 16 is being used to heat its environment and returned to the radiator 16 and its environment after the radiator 16 has been switched off.

[0106] In addition, in the above-described embodiment the TSU 1 is provided with hooks 15 that are mounted to the top panel 2c of the casing 2 and configured to extend over the top surface of the radiator 16 to which the TSU 1 is mounted, as shown in Fig. 7. However, other mounting systems are also possible. For example, Figure 8 schematically illustrates an alternative embodiment in which smaller hooks 15a are mounted to the rear panel 2b of the casing 2 and received within corresponding mounting loops 15b provided on the wall 18 behind the radiator 16 in order to releasably mount the TSU 1 to the wall 18 with its front surface against the rear surface of the radiator 16.

[0107] Figure 9 schematically illustrates a further embodiment comprising a pair of mounting bracket-receiving apertures 20 that are configured to receive wall-mounted brackets 21 that are used to mount a radiator to a wall therein. As shown in Figure 9, each of the mounting bracket-receiving apertures 20 comprises an elongate slot that extends in a direction aligned with the height of the casing 2 from an open lower end 20a provided at the bottom of the casing 2 to a closed upper end 20b located inboard of the top of the casing 2. The open lower ends 20a of the slots 20 enable the TSU 1 of Figure 9 to be lowered into a gap between a radiator and a wall to which the radiator is mounted around mounting brackets 21 that are used to mount the radiator to the wall, and the closed upper ends 20b of the slots 20 are configured to engage the mounting brackets 21 in order to support the weight of the TSU 1. In this case the TSU 1 may not require any additional mounting elements such as hooks 15 in order to facilitate mounting of the TSU 1 to the radiator 16 or wall 18. However, in other embodiments a TSU 1 including one or more mounting bracket-receiving apertures 20 may be mounted to the radiator 16 or wall 18 by one or more mounting elements such as hooks 15 that are provided separately to the mounting bracket-receiving apertures 20. In this case the mounting bracket-receiving apertures 20 may serve only to accommodate the radiator mounting brackets 21 , and may not be used to support the weight of the TSU 1.

[0108] The mounting bracket-receiving apertures 20 may each be provided with one or more pads on the inner surfaces thereof. The pads may, for example, extend up side edges of the slots 20, and optionally across the closed upper ends 20b of the slots 20. The pads may be formed of a resiliently compressible material and / or may have a high- friction surface. The pads may, for example, be formed of a compressible foam, a compressible foam with a high friction coating, or a rubber material. The pads may be configured to be compressed between the radiator mounting brackets 21 and the casing 2 of the TSU 1 , and may be configured to provide cushioning between the TSU 1 and the radiator mounting brackets 21 , to reduce or prevent lateral movement of the TSU 1 relative to the radiator 16 and / or to provide enhanced grip between the TSU 1 and the radiator mounting brackets 21 in order to provide increased resistance to dismounting of the TSU 1 from the radiator mounting brackets 21 .

[0109] In another embodiment the TSU 1 may be held in position relative to the radiator 16 by being received in a holder. The holder may be mounted to the rear face of the radiator 16 or to the wall 18 in order to retain the TSU 16 in the gap 19 between the radiator 16 and the wall 18. The holder may be open topped in order to enable the TSU 1 to be mounted to the radiator 16 or wall 18 by simply lowering the TSU 1 into the holder and removed from the radiator 16 or wall 18 by simply lifting the TSU 1 out of the holder in a vertical direction. The holder may comprise a container having a shape that at least substantially matches the shape of the TSU, or may comprise one or more hooks or brackets that are configured to engage and retain the TSU 1 . The holder may include a front face that is in contact with the rear face of the radiator 16 on one side thereof and in contact with the front face of the TSU 1 on the other side thereof in order to facilitate heat transfer between the radiator 16 and the TSU 1 .

[0110] In the above-described embodiment the TSU 1 is an aftermarket accessory that is configured to be retro-fitted to the radiator 16. However, in other embodiments the TSU 1 may be supplied together with a radiator 16 with which it is designed to cooperate.

[0111] In the above-described embodiment the TSU 1 is designed to be readily detached from the radiator 16 by an end user by simply lifting the TSU 1 in an upward direction away from the radiator 16 without interacting with any locking elements or fasteners. However, in other embodiments the TSU 1 may comprise one or more locking elements such as clips or latches for preventing accidental removal of the TSU 1 which must be released in order to remove the TSU 1 from the radiator 16, or may be semipermanently attached to the radiator 16, for example by one or more bolts or other fasteners that require removal before the TSU 1 can be removed from the radiator 16.

[0112] In the above-described embodiment the TSU 1 has a planar front face 1a. However, in other embodiments the front face 1 a of the TSU 1 may have a corrugated shape, as schematically illustrated in Figure 10, which may match the shape of the rear face of a radiator 16 with which the TSU 1 is used in order to increase the contact area between the TSU 1 and the radiator 16 and thereby maximise the efficiency of heat transfer between the radiator 16 and the TSU 1 .

[0113] In the above-described embodiment the TSU 1 is provided with a plurality of PCM- engaging fins 10 that are attached to the front panel 2a of the casing 2 and in contact with the PCM 4. However, in other embodiments the PCM-engaging fins 10 may be replaced by a metal foam, for example a copper foam, that is located inside the casing and in contact with the PCM.

[0114] In the above-described embodiment the outlets 6b of the air channels 6 are provided in the top face 1c of the TSU 1 such that air exiting the air channels 6 will leave the TSU 1 in a substantially vertical direction. However, in other embodiments the TSU 1 may be configured to direct air exiting the air channels 6 outwardly therefrom in a direction angled away from the front face 1a of the TSU 1. For example, the air channels 6 may be provided with flow-redirecting hoods which are configured to direct the flow of air leaving the air channels 6 outwardly from the TSU 1 in a direction substantially perpendicular to the front face 1 a of the TSU 1 . One such flow-redirecting hood 6b’ is shown in dashed lines in Figure 1 . In another embodiment a single flowredirecting hood could be provided which extends over each of the air channels 6 and is configured to redirect air leaving each of the air channels 6. The flow-redirecting hood(s) 6b’ could also be provided with movable flow-directing elements in their outlets that are configured to be moved in order to further control the direction in which air exits the air channels 6.

[0115] In another embodiment the outlets of the air channels 6 could be provided in the front panel 2a of the casing 2, as shown in dashed lines at 6b” in Figure 1 . In this case air exiting the air channels 6 may be redirected without the need for additional flowdirecting hoods. (It will be appreciated that in embodiments in which the outlets 6b” of the air channels 6 are provided in the front panel 2a of the casing 2 the mounting system of the TSU 1 would be modified to position the upper portion of the casing 2 in which the outlets 6b” are provided above the top of the radiator 16 to which the TSU 1 is mounted.) Other modifications and variations will also be apparent to the skilled person.

Claims

CLAIMS1 . A thermal storage unit (TSU) that is configured to be mounted in proximity to a radiator, the TSU comprising a casing and a phase change material (PCM) located inside the casing that is configured to absorb and store thermal energy from the radiator when the radiator is being used to heat an environment in which it is located, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off.

2. A TSU according to Claim 1 , wherein the TSU comprises a forced convection system including at least one air channel that extends through the TSU and at least one fan or blower unit that is configured to move air through the air channel.

3. A TSU according to Claim 2, wherein the or each air channel extends between a first opening provided at a bottom of the TSU and a second opening provided at a top of the TSU.

4. A TSU according to Claim 2 or Claim 3, wherein the or each air channel includes at least one air channel fin that extends into the air channel.

5. A TSU according to any of Claims 2 to 4, wherein the TSU includes at least one user-operable interface element that is configured to control operation of the fan or blower unit(s).

6. A TSU according to any preceding claim, wherein the TSU comprises at least one PCM-engaging fin that is located inside the casing and in contact with the PCM.

7. A TSU according to Claim 6, wherein the PCM-engaging fin(s) are connected to a front wall of the casing.

8. A TSU according to Claim 6 or Claim 7, wherein the PCM-engaging fin(s) are spaced apart from a rear wall of the casing.

9. A TSU according to any of Claims 6 to 8, wherein the PCM-engaging fin(s) are provided with perforations.

10. A TSU according to any of Claims 6 to 9, wherein the PCM-engaging fin(s) have a corrugated or waveform shape when viewed from above, or wherein the PCM- engaging fins each include a main body and at least one projecting portion that projects outwardly from the main body.

11. A TSU according to any preceding claim, wherein the TSU is configured to be readily mounted to and detached from a radiator or wall by an end user.

12. A TSU according to any preceding claim, wherein the TSU is configured to be mounted to a radiator or wall by lowering the TSU into position relative to the radiator or wall and / or to be detached from a radiator or wall by lifting the TSU away from the radiator or wall in a vertical direction.

13. A TSU according to any preceding claim, wherein the TSU comprises at least one mounting element that is configured to enable the TSU to be mounted to a radiator or wall.

14. A TSU according to Claim 13, wherein the at least one mounting element comprises one or more hooks, loops, brackets or clamps.

15. A TSU according to any preceding claim, wherein the TSU comprises at least one aperture that extends through the thickness of the TSU and is configured to receive a mounting bracket of a radiator therein.

16. A TSU according to any preceding claim, wherein the TSU comprises at least one handle.

17. A TSU according to any preceding claim, wherein the TSU includes a metal foam, optionally copper foam, that is located inside the casing and in contact with the PCM.

18. A TSU according to any preceding claim, wherein the TSU comprises a layer of insulation provided on a rear face of the TSU.

19. A TSU according to any preceding claim, comprising at least one temperature sensor that is configured to sense a temperature of the PCM.

20. A TSU according to Claim 19, comprising an output element that is configured to provide an indication of the temperature of the PCM as determined by the temperature sensor and / or to provide a notification when the temperature of the PCM has reached a predetermined value.

21. A TSU according to Claim 19 or 20, wherein the TSU comprises a communication module that is configured to output a signal representative of the temperature of the PCM as determined by the temperature sensor and / or to output a signal representative of whether or not the temperature of the PCM has reached a predetermined value.

22. Apparatus for providing thermal energy to an environment, the apparatus comprising a radiator and a TSU according to any preceding claim mounted in proximity to the radiator, wherein the TSU is configured to absorb and store thermal energy from the radiator when the radiator is being used to heat the environment, and to return the stored thermal energy to the radiator and / or to the environment after the radiator has been switched off.

23. Apparatus for providing thermal energy to an environment according to Claim 22, wherein the TSU is located in a gap formed between the radiator and a wall.

24. Apparatus for providing thermal energy to an environment according to Claim 22 or Claim 23, wherein a front face of the TSU is in contact with a rear face of the radiator.

25. Apparatus for providing thermal energy to an environment according to any of Claims 22 to 24, wherein the TSU is supplied separately to the radiator and retrofitted to the radiator as an aftermarket accessory.

26. A method of heating an environment, the method comprising: a) mounting a TSU according to any proceeding claim in proximity to a radiator; b) using the radiator to heat the environment; c) absorbing thermal energy from the radiator into the TSU while the radiator is being used to heat the environment, and storing the thermal energy in the PCM; d) returning the stored thermal energy from the TSU to the radiator and / or to the environment.

27. A method according to Claim 26, further comprising a step of switching the radiator off or reducing the temperature of the radiator between the step of absorbing thermal energy from the radiator into the TSU and the step of returning the stored thermal energy from the TSU to the radiator and / or to the environment.

28. A method according to Claim 26 or Claim 27, further comprising a step of moving the TSU to a different location after the step of absorbing thermal energy from the radiator into the TSU in order to enable thermal energy to be released from the TSU at a different location to the radiator.

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