Patent Description:
In aircraft and other vehicles, thermal management is used to ensure vehicle components and systems remain within their desired operating temperature range. Thermal management is particularly important for systems that have high peak energy consumption, and which operate on demand rather than with a steady energy throughput. Such systems have the potential to generate large amounts of heat in a short period of time. That heat can build up more rapidly than can be lost through natural heat dissipation or disposed of via a primary cooling system for the vehicle, such as the cooling system which deals with cooling the vehicle's interior or engines.

For example, laser directed energy weapons (LDEWs) which can be mounted to aircraft or other vehicles have high peak energy consumption and typically need to manage a significant amount of heat generated while the laser is in use over a short time period. Even if integrated into the primary cooling system of the vehicle to which the LDEW is mounted, disposing of excess heat generated during LDEW use can be a limiting factor on LDEW operation. This is particularly the case when the LDEW has different usage patterns according to operational requirements.

In addition, as with all vehicle-mounted systems, there are restrictions on space and weight that can be dedicated to thermal management apparatus. Thus, there is a desire for a small, lightweight and adaptable thermal management apparatus.

<CIT> describes a cooling system comprising a phase change material energy store and ram air primary cooling source for an aircraft.

<CIT> describes a thermal management system for a vehicle comprising a phase-change material arranged to cool an onboard system.

<CIT> describes a multi-evaporator cooling system for use with a vehicle.

<CIT> describes an environmental control system for use with a vehicle comprising phase change heat exchange units.

<CIT> describes a thermal control system for an avionics pod.

In one aspect there is provided a thermal management apparatus for use with a vehicle according to claim <NUM>.

In one example, one or more of the phase change heat exchange units is thermally coupled to a primary cooling system of the vehicle to discharge heat thereto. In one example, each of the phase change heat exchange units is thermally coupled to a primary cooling system of the vehicle. In one example, all of the phase change heat exchange units are thermally coupled to a primary cooling system of the vehicle. In one example this primary cooling system is an engine cooling system of the vehicle, and/or an interior cooling system of the vehicle. The primary cooling system comprises engine cooling and/or interior cooling of the vehicle.

A thermal management apparatus that comprises a plurality of phase change heat exchange units, also known as phase change heat exchangers, that are thermally coupled with a system that requires thermal management takes advantage of the size and weight advantages of individual phase change heat exchange units, enabling flexibility in locating the individual units in a vehicle. Furthermore, flexibility in thermal management is achieved as it is possible to vary the operation of the phase change heat exchange units according to operational requirements of the system to which they are thermally connected. The phase change heat exchange units serve as a buffer between the system to which they are thermally connected and other cooling systems or equipment such as the primary cooling system of a vehicle.

The thermal management apparatus comprises a manifold, operable to control delivery of heat from the vehicle system to the phase change heat exchange units. In one example, the manifold is operable to direct heat from the vehicle system to a subset of the phase change heat exchange units.

In one example, the manifold is operable to selectively control delivery of heat from the vehicle system to the phase change heat exchange units. In one example, the manifold is operable to selectively control delivery of heat from the vehicle system to individual phase change heat exchange units in the plurality of phase change heat exchange units.

The thermal management apparatus comprises a controller arranged to control the manifold.

In one example, the controller is arranged to control the manifold to deliver heat from the vehicle system to two or more phase change heat exchange units simultaneously.

In one example, the controller is arranged to control the manifold to deliver heat from the system to all of the phase change heat exchange units simultaneously.

In one example, the controller is arranged to control the manifold to deliver heat from the system to two or more phase change heat exchange units in parallel, for example all of the phase change heat exchange units in parallel.

In one example, the controller is arranged to control the manifold to deliver heat from the system to a first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to control the manifold to deliver heat from the system to a second phase change heat exchange unit.

In one example, the controller is arranged to control the manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence. In one example, the controller is arranged to control the manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence such that heat from the vehicle system is delivered to one first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to the next. In one example, the controller is arranged to control the manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence such that heat from the vehicle system is delivered to one first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to the next until all capacity of all the units to receive heat is exhausted. In one example, the controller is arranged to control the manifold to deliver heat from the vehicle system to phase change heat exchange units cyclically.

The phase change heat exchange units are operatively coupled to the controller to provide an indication of their capacity to receive heat.

In one example, the thermal management apparatus comprises one or more temperature sensors arranged to provide temperature information to the controller. In one example, the thermal management apparatus comprises one or more temperature sensors that in use are operatively coupled to the vehicle system.

In one example, the controller comprises a system interface that is in use arranged to interface with the vehicle system that requires thermal management.

In one example the controller is in use arranged to communicate with the vehicle system through the system interface to control operation of the vehicle system.

In one example the controller is arranged to control operation of the vehicle system according to the heat absorbing capacity of the phase change heat exchange units.

In one example the controller is arranged to control operation of the vehicle system according to cool down ratio of the phase change heat exchange units.

In one example the controller is arranged to control operation of the vehicle system according to temperature of the vehicle system.

In one example the controller is arranged to control operation of the vehicle system by inhibiting operation thereof while the temperature of the system is above an operating threshold.

In one example the controller is arranged to control operation of the vehicle system by inhibiting operation thereof while the heat absorbing capacity of the phase change heat exchange units is below a threshold capacity.

In one example, the vehicle system comprises an electronics system. In one example, the vehicle system comprises a defence system. In one example, the vehicle system comprises a laser directed energy weapon.

In one example, one or more of the phase change heat exchange units is thermally coupled to a heat sink on the vehicle. In one example, each of the phase change heat exchange units is thermally coupled to a heat sink on the vehicle. In one example, all of the phase change heat exchange units are thermally coupled to a heat sink on the vehicle.

In one example, one or more of the phase change heat exchange units is thermally coupled to a structural component of the vehicle. In one example, each of the phase change heat exchange units is coupled to a structural component on the vehicle. In one example, all of the phase change heat exchange units are thermally coupled to a structural component on the vehicle. In one example the structural component comprises a chassis of the vehicle. In one example the structural component comprises an airframe of the vehicle. In one example the structural component comprises a fuselage of the vehicle.

In another aspect, according to claim <NUM>, there is provided a vehicle comprising the thermal management apparatus as set out herein. In one example the vehicle comprises an aircraft. Aircraft are subject to restrictions on available space and weight that can be dedicated to thermal management apparatus, so a thermal management apparatus as described reduces problems of integration with the vehicle while enabling flexibility in operation to match to operational requirements of the system to which the phase change heat exchange units are thermally connected.

In another aspect there is provided a method of thermal management according to claim <NUM>.

The method comprises operating a manifold to control delivery of heat from the vehicle system to the phase change heat exchange units. In one example, the method comprises operating a manifold to direct heat from the vehicle system to a subset of the phase change heat exchange units.

In one example, the method comprises operating a manifold to selectively control delivery of heat from the vehicle system to the phase change heat exchange units. In one example, the method comprises operating a manifold to selectively control delivery of heat from the vehicle system to individual phase change heat exchange units in the plurality of phase change heat exchange units.

In one example, the method comprises operating a controller to control a manifold to deliver heat from the vehicle system to two or more phase change heat exchange units simultaneously.

In one example, the method comprises operating a controller a manifold to deliver heat from the system to all of the phase change heat exchange units simultaneously.

In one example, the method comprises operating a controller to control a manifold to deliver heat from the system to two or more phase change heat exchange units in parallel, for example all of the phase change heat exchange units in parallel.

In one example, the method comprises operating a controller to control a manifold to deliver heat from the system to a first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to control the manifold to deliver heat from the system to a second phase change heat exchange unit.

In one example, the method comprises operating a controller to control a manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence. In one example, the method comprises operating a controller to control a manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence such that heat from the vehicle system is delivered to one first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to the next. In one example, the method comprises operating a controller to control a manifold to deliver heat from the vehicle system to the phase change heat exchange units in sequence such that heat from the vehicle system is delivered to one first phase change heat exchange unit until that unit's capacity to receive heat is exhausted, then to the next until all capacity of all the units to receive heat is exhausted. In one example, the method comprises operating a controller to control a manifold to deliver heat from the vehicle system to phase change heat exchange units cyclically.

The method comprises providing status information of the phase change heat exchange units to a controller to provide an indication of their capacity to receive heat.

In one example, the method comprises providing temperature information of the vehicle system to a controller. In one example, the method comprises sensing the temperature of the vehicle system.

In one example, the method comprises communicating with the vehicle system through to control operation of the vehicle system.

In one example the method comprises controlling operation of the vehicle system according to the heat absorbing capacity of the phase change heat exchange units.

In one example the method comprises controlling operation of the vehicle system according to cool down ratio of the phase change heat exchange units.

In one example the method comprises controlling operation of the vehicle system according to temperature of the vehicle system.

In one example the method comprises controlling operation of the vehicle system by inhibiting operation thereof while the temperature of the system is above an operating threshold.

In one example the method comprises controlling operation of the vehicle system by inhibiting operation thereof while the heat absorbing capacity of the phase change heat exchange units is below a threshold heat capacity.

Referring now to <FIG>, a thermal management apparatus for use with a vehicle is denoted as a whole by the reference numeral <NUM>.

The thermal management apparatus <NUM> comprises a plurality of phase change heat exchange units <NUM> that are thermally coupled with a vehicle system that requires thermal management, the plurality of phase change heat exchange units operable to remove heat from the vehicle system. In the embodiment of <FIG> three phase change heat exchange units <NUM> are present.

<FIG> shows a vehicle <NUM> comprising the thermal management apparatus <NUM>. While the vehicle <NUM> shown here comprises an aircraft, it would be readily appreciated that the present invention is applicable to other types of vehicles such as ships, land vehicles and so on.

The vehicle <NUM> comprises various electronics systems that require thermal management to prevent overheating, including a laser directed energy weapon (LDEW) <NUM>. In use, the LDEW <NUM> generates a significant amount of heat, which poses a limiting factor on LDEW operation due to the amount of time required for the LDEW <NUM> to cool down before it can be used again.

The phase change heat exchange units <NUM> are thermally coupled to a primary cooling system <NUM> of the vehicle <NUM> to aid removal of heat from the phase change heat exchange units <NUM>. The primary cooling system <NUM> may include active or forced cooling, alongside passive cooling elements such as specifically provisioned heat sinks (not shown) or by thermal coupling to one or more structural components on the vehicle <NUM>. The primary cooling system <NUM> comprises engine cooling and/or interior cooling of the vehicle. Here, the primary cooling system includes cooling systems pre-existing in the vehicle, or otherwise arranged for steady state/normal vehicle operations, i.e. not operations of the vehicle system that requires thermal management, in this example the LDEW <NUM>.

In <FIG>, the arrows shown as interconnecting the thermal management apparatus <NUM>, the LDEW <NUM> and the primary cooling system <NUM> of the vehicle <NUM> represent paths for heat transfer. <FIG> does not show interconnections for transmission of sensed temperature information, which are described in more detail below.

Referring back to <FIG>, the thermal management apparatus <NUM> comprises a manifold <NUM>, operable to control delivery of heat from the LDEW <NUM> to the phase change heat exchange units <NUM>. The manifold <NUM> is operable to direct heat from the LDEW <NUM> to a subset of the phase change heat exchange units <NUM>.

Due to their ability to rapidly absorb the heat load generated by the LDEW <NUM>, the phase change heat exchange unit units <NUM> provide a compact and effective cooling solution for laser applications. However, typical phase change heat exchange units have a <NUM>:<NUM> cool down ratio; that is, if the heat exchange unit's capacity to absorb heat is exhausted in <NUM> seconds, <NUM> seconds is required to re-cool the phase change heat exchange unit <NUM> so that it is again ready to absorb heat for another <NUM> seconds.

The manifold <NUM> is operable to selectively control delivery of heat from the LDEW <NUM> to individual phase change heat exchange units <NUM> in the plurality of phase change heat exchange units <NUM>.

The phase change heat exchange units <NUM> are operatively coupled to the controller <NUM> to provide information on their capacity to receive heat.

The thermal management apparatus <NUM> comprises a controller <NUM> arranged to control the manifold <NUM>, based on the phase change heat exchange units' capacity to receive heat. The controller <NUM> is arranged to control the manifold <NUM> to deliver heat from the vehicle system to one, two or more phase change heat exchange units <NUM> simultaneously. Thus, the heat generated by the LDEW <NUM> can be directed to the phase change heat exchange units <NUM> which have capacity to receive heat, i.e. are not currently re-cooling.

Depending on operational requirements, the controller <NUM> may be arranged to control the manifold <NUM> to deliver heat from the system to a first phase change heat exchange unit <NUM> until that unit's capacity to receive heat is exhausted, then to control the manifold <NUM> to deliver heat from the system to a second phase change heat exchange unit <NUM>, the second phase change heat exchange unit capable of receiving heat, and so on, in sequence, cyclically. This method of operation is suitable for enabling a longer burst of operation of the LDEW <NUM>, with corresponding longer cooling delay. Alternatively, to reduce the time between bursts of a shorter duration, the manifold <NUM> is controllable to deliver heat from the LDEW <NUM> to the phase change heat exchange units <NUM> in parallel, so that as much heat as possible is absorbed as quickly as possible after each individual burst of operation of the LDEW <NUM>.

In addition to controlling the manifold <NUM> to direct heat to the plurality of phase change heat exchange units <NUM>, the controller <NUM> is arranged to control operation of the LDEW <NUM> according to the remaining cooling capacity of the phase change heat exchange units <NUM> and/or the temperature of the LDEW <NUM>. Sensors (not shown) are provided that enable to controller <NUM> to determine the temperature of the LDEW <NUM>, the phase change heat exchange units <NUM>, and optionally the primary cooling system <NUM> of the vehicle <NUM>. By monitoring the operation of the LDEW <NUM> and its temperature, the temperature of the phase change heat exchange units <NUM> and the performance of the primary cooling system <NUM> the controller <NUM> determines the available operating capacity of the LDEW <NUM>. For example, the controller <NUM> inhibits operation of the LDEW <NUM> while the temperature of the LDEW <NUM> is above an operating threshold, and/or while the heat absorbing capacity of the phase change heat exchange units <NUM> is below a threshold capacity. In this way the LDEW <NUM> can be maximally operated without overheating.

<FIG> shows an example of a method of thermal management, applicable to the vehicle <NUM> of <FIG>.

At step <NUM>, the method comprises delivering heat from a vehicle system that requires thermal management to a plurality of phase change heat exchange units. The method is performed by a thermal management apparatus on a vehicle as set out herein.

The method comprises operating a manifold to control delivery of heat from the vehicle system to the phase change heat exchange units.

The method comprises communicating with the vehicle system to control operation of the vehicle system. The method comprises controlling operation of the vehicle system according to the heat absorbing capacity of the phase change heat exchange units, cool down ratio of the phase change heat exchange units, and/or temperature of the vehicle system.

The method comprises controlling operation of the vehicle system by inhibiting operation thereof while the temperature of the system is above an operating threshold and/or while the heat absorbing capacity of the phase change heat exchange units is below an operating threshold.

Claim 1:
A thermal management apparatus (<NUM>) for use with a vehicle (<NUM>), the apparatus comprising:
a plurality of phase change heat exchange units (<NUM>) thermally coupled with a vehicle system (<NUM>) that requires thermal management, the plurality of phase change heat exchange units operable to remove heat from the vehicle system;
a manifold (<NUM>) operable to control delivery of heat from the vehicle system to the phase change heat exchange units; characterized by
a controller (<NUM>) arranged to control the manifold,
wherein the phase change heat exchange units are operatively coupled to the controller to provide an indication of their capacity to receive heat.