Patent Description:
The thermal cycling of these components does not remain constant during a flight. Rather, each component may have a normal operating temperature based on normal power consumption during the flight and peak operating temperatures resulting from specific events occurring during the flight. For example, the heat of a motor and/or inverter of a propeller arrangement of the aircraft may increase during take-off, landing, hovering, or turning of the aircraft compared to the temperature during cruising. The heat of the battery also may cycle based on how much power is drawn by the propeller arrangements or other components during the flight. Accordingly, the thermal management system is typically configured to provide sufficient cooling for the expected elevated temperatures.

<CIT> relates to an example of a thermal management system for an aircraft. It comprises a first cooling loop with a refrigerant, a first heat exchanger associated with a battery, a compressor, a second heat exchanger and an expander; and a second cooling loop with a third heat exchanger associated with a propeller motor, a fourth heat exchanger cooled by air, a coolant reservoir and a pump, the second cooling loop passing through the second heat exchanger.

<CIT>, <CIT> and <CIT> relate to examples of thermal management systems for batteries of hybrid vehicles.

The invention relates to a thermal management system for an aircraft as defined in claim <NUM> and to a method of cooling a propeller arrangement of an aircraft as defined in claim <NUM>.

In certain implementations, the liquid-cooled condenser is cooled by the second coolant circulating through the propeller arrangement cooling loop.

In certain implementations, an electronic controller and a valve arrangement determines how much of the second coolant is directed to the liquid-cooled condenser. In certain examples, the amount and/or flowrate of second coolant directed to the liquid-cooled condenser is increased when the ambient temperature exceeds a predetermined threshold (e.g., above <NUM> degrees Celsius) and/or when a cooling load of the battery exceeds another predetermined threshold (e.g., based on a upper temperature limit for which the battery is rated). In certain examples, the amount and/or flowrate of second coolant directed to the liquid-cooled condenser is decreased when the ambient temperature drop below a predetermined threshold (e.g., below <NUM> degrees Celsius) and/or when a cooling load of the battery drops below another predetermined threshold (e.g., based on a lower temperature limit for which the battery is rated).

In certain implementations, the second coolant circulating through the propeller arrangement cooling loop can be directed to the chiller to be further cooled by the refrigeration loop. In some examples, the second coolant is kept separate from the first coolant when routed through the chiller. In other examples, the second coolant is combined with the first coolant when routed through the chiller.

A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows:.

Reference will now be made in detail to exemplary aspects of the present disclosure that are illustrated in the accompanying drawings.

An aircraft <NUM> includes a fuselage <NUM> defining a cabin sized to carry a pilot and one or more passengers. The aircraft <NUM> also includes a first wing <NUM> and a second wing <NUM> that each carry one or more propeller arrangements <NUM> or other propulsion components. In the example shown, three propeller arrangements <NUM> are disposed at each wing <NUM>, <NUM>. In other examples, however, each wing <NUM>, <NUM> may carry any desired number or propulsion components. In certain examples, each propeller arrangement <NUM> includes a propeller, a motor, and an inverter to operate the propeller arrangement <NUM>. Other configurations are possible.

The aircraft <NUM> includes a power system <NUM> including at least one battery <NUM> that powers the propeller arrangements <NUM> via a power bus <NUM>. In the example shown, the propeller arrangements <NUM> are powered by a main battery <NUM> carried by the fuselage <NUM>. In other examples, the propeller arrangements <NUM> may be powered by one or more batteries <NUM> carried by the wings <NUM>, <NUM>. In certain implementations, the power system <NUM> also provides electric power to other components of the aircraft such as the flight management system, the control display unit, and/or lighting. In certain implementations, the power system <NUM> also provides electric power to one or more components <NUM> (e.g., a compressor, a pump, etc.) of a thermal management system <NUM> used to cool the battery <NUM> and/or other components such as the propeller arrangement <NUM>.

<FIG> illustrates an example thermal management system <NUM> including one or more cooling circuits <NUM>, <NUM>, <NUM>, <NUM> that cool various components of the aircraft <NUM>. In the illustrated example, the thermal management system <NUM> includes a battery cooling circuit <NUM> configured to cool one or more batteries <NUM> of the power system <NUM>, a first propeller arrangement cooling circuit <NUM> configured to cool one or more of the propeller arrangements <NUM>, and a refrigeration circuit <NUM> configured to cool one or more of the cooling circuits <NUM>, <NUM>. In the example shown, only one propeller arrangement <NUM> and corresponding cooling circuit <NUM> is shown. It will be understood however, that the same cooling circuit <NUM> may service multiple propeller arrangements <NUM>. In other examples, each propeller arrangement <NUM> may have a respective battery <NUM> and battery cooling circuit <NUM>.

The refrigeration circuit <NUM> includes a conduit <NUM> through which the refrigerant (e.g., a Hydrofluorocarbon such as R-134a or R410A or other refrigerant) is carried through the refrigeration circuit <NUM>. The refrigeration circuit <NUM> also includes a compressor <NUM> configured to draw the refrigerant along the conduit <NUM> and to pressurize (e.g., vaporize) the refrigerant; a condenser arrangement <NUM> at which heat is removed from the pressurized refrigerant; and an expansion valve <NUM> at which a pressure drop is created so that low temperature, low pressure refrigerant is then conveyed to the chiller <NUM>.

In certain implementations, the condenser arrangement <NUM> includes a liquid-cooled condenser <NUM> at which at least some heat is removed from the pressurized refrigerant; and an air-cooled condenser <NUM> at which additional heat is removed from the pressurized refrigerant. In some implementations, the refrigeration circuit <NUM> circulates the refrigerant through the liquid-cooled condenser <NUM> before circulating the refrigerant through the air-cooled condenser <NUM> (e.g., see <FIG>). In other implementations, however, the refrigerant may be circulated through the air-cooled condenser <NUM> first. In certain implementations, the air-cooled condenser <NUM> is exposed to ambient air outside the aircraft <NUM> or air routed from outside the aircraft to the air-cooled condenser <NUM>.

The battery cooling circuit <NUM> includes a tank <NUM> configured to hold coolant (e.g., water, propylene glycol, ethylene glycol, or other antifreeze solution), a pump <NUM> configured to draw the coolant from the tank <NUM>, and a conduit <NUM> along which the coolant flows through the battery cooling circuit <NUM>. During standard operation, the conduit <NUM> is directed from the pump <NUM> towards the battery <NUM>. After absorbing heat from the battery <NUM>, the coolant is directed to a chiller <NUM> at which heat is rejected from the coolant to the refrigerant passing through the refrigeration circuit <NUM>. The cooled coolant then passes back to the tank <NUM> (e.g., see <FIG>).

The propeller arrangement cooling circuit <NUM> includes a conduit <NUM> through which coolant flows through the circuit <NUM>. The propeller arrangement cooling circuits <NUM> also includes a tank <NUM>, a pump arrangement <NUM> of one or more pumps to draw coolant from the tank <NUM> and circulate the coolant through the conduit <NUM>, and a radiator arrangement <NUM> exposed to ambient air outside the aircraft. The coolant passes from the pump arrangement <NUM> to a motor and/or an inverter of one or more of the propeller arrangements <NUM> from which heat is absorbed by the coolant. The heated coolant is air cooled at the radiator <NUM> before returning to the tank <NUM> (e.g., see <FIG>).

As shown in <FIG>, the radiator arrangement <NUM> includes one or more radiators. In certain such implementations, a flow control valve <NUM> directs coolant flow to the one or more of the radiators. For example, the flow control valve <NUM> may control how much coolant flows to each radiator. In certain examples, the radiator arrangement <NUM> includes a radiator for each propeller arrangement <NUM>. In the example shown, the radiator arrangement <NUM> includes three radiators 152a, 152b, 152c. In other examples, the radiator arrangement <NUM> may includes a greater or lesser number of radiators. In some implementations, the radiator arrangement <NUM> includes all of the radiators disposed on a wing <NUM>, <NUM> of the aircraft <NUM>. In other implementations, the radiator arrangement <NUM> includes all of the radiators disposed on both wings <NUM>, <NUM> (e.g., by fluidly combining propeller arrangement cooling circuits <NUM> of both wings <NUM>, <NUM>).

In accordance with some aspects of the disclosure, the liquid-cooled condenser <NUM> is cooled by the coolant circulated by the pump <NUM> of the propeller arrangement cooling circuit <NUM>. For example, the propeller arrangement cooling circuit <NUM> includes a condenser routing path <NUM> leading past the liquid-cooled condenser <NUM> of the refrigeration circuit <NUM>. Coolant routed along the condenser routing path <NUM> cools the vaporized refrigerant within the condenser <NUM>.

In some implementations, the condenser routing path <NUM> extends to the liquid-cooled condenser <NUM> from a location upstream of the propeller arrangement <NUM> (e.g., see <FIG>). For example, a first valve arrangement <NUM> (e.g. a directional control valve) may be disposed downstream of the pump arrangement <NUM> and downstream of the propeller arrangement <NUM>. The first valve arrangement <NUM> may direct a first portion (e.g., some, all, or none) of the coolant drawn from the tank <NUM> to the propeller arrangement <NUM> (e.g., see <FIG>). The first valve arrangement <NUM> also may direct a second portion (e.g., some, all, or none) of the coolant drawn from the tank <NUM> along the condenser routing path <NUM> to the liquid-cooled condenser <NUM> (e.g., see <FIG> and <FIG>). In certain examples, the first portion is larger than the second portion. In certain examples, the first valve arrangement <NUM> selectively closes the condenser routing path <NUM> and directs all of the coolant to the propeller arrangement <NUM> (e.g., see <FIG>).

As shown in <FIG>, the cooled coolant flowing from the radiator arrangement <NUM> may be further cooled by the refrigeration circuit <NUM>. For example, a downstream valve arrangement <NUM> is disposed downstream of the radiator arrangement <NUM>. A first return path <NUM> extends from the downstream valve arrangement <NUM> to the tank <NUM> of the propeller arrangement cooling circuit <NUM>. A second return path <NUM> extends from the downstream valve arrangement <NUM> to the chiller <NUM> and then back to the tank <NUM>. The downstream valve arrangement <NUM> is configured to selectively direct the coolant from the radiator arrangement <NUM> along the first return path <NUM> and/or along the second return path <NUM>.

For example, if the ambient temperature Tamb of air outside the aircraft <NUM> is below a first threshold T1 (e.g., below <NUM> degrees Celsius, below <NUM> degrees Celsius, below <NUM> degrees Celsius, etc.), then the radiator arrangement <NUM> is able to provide sufficient cooling to accommodate the heat load from both the propeller arrangement <NUM> and the liquid-cooled condenser <NUM>. In such cases, the downstream valve arrangement <NUM> may direct all of the coolant from the radiator <NUM> back to the tank <NUM>. On the other hand, if the ambient temperature Tamb is above a threshold T2 (e.g., <NUM> degrees Celsius, <NUM> degrees Celsius, <NUM> degrees Celsius, etc.), then the downstream valve arrangement <NUM> may direct all of the coolant from the radiator <NUM> to pass through the chiller <NUM>. If the ambient temperature Tamb is between the thresholds T1 and T2, then the downstream valve arrangement <NUM> may direct a portion of the coolant from the radiator <NUM> to the tank <NUM> and another portion of the coolant to the chiller <NUM> for additional cooling before being returned to the tank <NUM>. Of course, in the event of a fault in the radiator arrangement <NUM>, some or all of the coolant may be directed to the chiller <NUM> for cooling regardless of the ambient temperature.

In some implementations, each of the coolant circuits <NUM>, <NUM> operates independently. For example, the battery cooling circuit <NUM> has a first coolant that circulates around the battery cooling circuit <NUM> including along a first path through the chiller <NUM> while the propeller arrangement cooling circuit <NUM> has a second coolant that circulates around the propeller arrangement cooling circuit <NUM> including along a separate, second path through the chiller <NUM> (e.g., see <FIG>).

In other implementations, one or more of the coolant circuits <NUM>, <NUM> may be fluidly coupled together by a return valve <NUM> (e.g., a directional control valve). For example, the coolant circuits <NUM>, <NUM> may be fluidly coupled during a failure of one or more components of one of the coolant circuits or during a period where one or more components of the power system <NUM> require extra cooling. In certain implementations, the first coolant of the battery arrangement cooling circuit <NUM> is combined with the second coolant of the propeller arrangement cooling circuit <NUM> prior to passing through the chiller <NUM> (e.g., see <FIG>). The combined fluid may pass along a common pathway through the chiller <NUM>. Downstream of the chiller <NUM>, the combined coolant may be directed to the return valve <NUM>, which directs some of the coolant along a battery circuit return path <NUM> towards the tank <NUM> of the battery cooling circuit <NUM> and other of the coolant along a propeller circuit return path <NUM> towards the tank <NUM> of the propeller arrangement cooling circuit <NUM>.

<FIG> illustrates an alternative configuration of the thermal management system <NUM> in which coolant is routed to the liquid-cooled condenser <NUM> after being routed past the propeller arrangement <NUM>. Accordingly, the coolant absorbs heat from the propeller arrangement <NUM> and from the liquid-cooled condenser <NUM> before being routed to the radiator arrangement <NUM>. For example, a valve arrangement <NUM> may be disposed downstream of the propeller arrangement <NUM> and upstream of the radiator arrangement <NUM>. The valve arrangement <NUM> (e.g., a directional control valve) selectively directs coolant flow from the propeller arrangement <NUM> along a first route towards the radiator arrangement <NUM> and/or along a second route towards the liquid-cooled condenser <NUM>. From the liquid-cooled condenser <NUM>, the heated coolant is routed toward the radiator arrangement <NUM>. In other implementations, the thermal management system <NUM> does not include a valve arrangement <NUM> and instead directs all heated coolant from the propeller arrangement <NUM> to the liquid-cooled condenser <NUM>.

In certain implementations, routing the coolant to both the propeller arrangement <NUM> and the liquid-cooled condenser <NUM> allows a greater level of fluid flow past these components. In certain implementations, the coolant directed to both the propeller arrangement <NUM> and the liquid-cooled condenser <NUM> is cooled at both the radiator arrangement <NUM> and the chiller <NUM> (e.g., see the second return path <NUM> of <FIG> and <FIG>).

As shown in <FIG>, an electronic controller <NUM> manages operation of various components of the thermal management system <NUM>. The electronic controller <NUM> includes a memory storing operation instructions and a processor configured to implement the operation instructions. In certain examples, the electronic controller <NUM> manages operation of the pumps <NUM>, <NUM> of the coolant circuits <NUM>, <NUM> and the compressor <NUM> of the refrigeration circuit <NUM> via control lines <NUM>. In certain examples, the electronic controller <NUM> manages operation of the various valves <NUM>, <NUM>, <NUM>, <NUM>, <NUM> (e.g., directional control valves, flow control valves, etc.) to direct coolant flow through the thermal management system <NUM> via control lines <NUM>. In certain examples, the electronic controller <NUM> manages operation of one or more temperature sensors T via control lines <NUM>. The temperature sensors T are configured to measure temperatures (or other properties from which temperature may be derived) along the coolant flow paths of the cooling circuits <NUM>, <NUM>, at various power components (e.g., the battery <NUM>, the propeller arrangement <NUM>, etc.), and/or outside the aircraft (e.g., to determine an ambient temperature). Representative control lines <NUM>, <NUM>, <NUM> are shown in <FIG>.

During a flight, the various powered components of the aircraft <NUM> draw power generally consistently except during certain high power events (e.g., take-off, landing, hovering, turning, etc.). One or more powered components (e.g., one or more propeller arrangements <NUM>, the battery <NUM>, etc.) may need extra cooling during these high power events. Throughout the flight, the electronic controller <NUM> may monitor temperatures of various components (e.g., the battery <NUM>, the first condenser <NUM>, the propeller arrangement <NUM>, etc.) and may adjust the coolant flow through the thermal management system <NUM> as needed. For example, the electronic controller <NUM> may connect and disconnect the coolant circuits <NUM>, <NUM> as needed to provide more or less cooling to select components. The electronic controller <NUM> also may increase or decrease an amount of coolant flow along the battery cooling circuit <NUM> and/or along the propeller arrangement cooling circuit <NUM> (e.g., by speeding up or slowing down the pumps <NUM>, <NUM>). Similarly, the electronic controller <NUM> also may increase or decrease the refrigerant flow along the refrigeration circuit <NUM> (e.g., by speeding up or slowing down the compressor <NUM>).

<FIG> is a flow chart illustrating an example process <NUM> by which the electronic controller <NUM> manages the thermal management system <NUM> during a flight. The process <NUM> includes a determine operation <NUM> at which a battery cooling load BCL for the battery <NUM> is determined. For example, the electronic controller <NUM> may measure a temperature of the battery <NUM>. At module <NUM>, the process <NUM> determines whether the cooling load BCL of the battery <NUM> exceeds a predetermined threshold Bmax that is set based on a maximum temperature for which the battery <NUM> is rated. In an example, the threshold Bmax is set at the maximum temperature for which the battery <NUM> is rated. In another example, the threshold Bmax is set a few (e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>) degrees below the maximum temperature for which the battery <NUM> is rated.

If the process <NUM> determines the battery is not too hot at module <NUM>, then the process <NUM> proceeds to a detect operation <NUM> at which a temperature Tamb of ambient air outside the aircraft <NUM> is obtained. At module <NUM>, the process <NUM> determines whether the ambient temperature Tamb is above a predetermined threshold Tmax. In an example, the threshold Tmax is set based on a temperature at which the air-cooled condenser <NUM> provides inadequate cooling to the coolant. In various examples, the threshold Tmax may be <NUM> degrees Celsius, <NUM> degrees Celsius, <NUM> degrees Celsius, <NUM> degrees Celsius, etc.). In an example, the threshold Tmax is set based on a temperature at which the radiator <NUM> provides inadequate cooling to the propeller arrangement <NUM> during normal operation. In various examples, the threshold Tmax may be <NUM> degrees Celsius, <NUM> degrees Celsius, <NUM> degrees Celsius, etc.).

If the process <NUM> determines the ambient temperature is not too warm at module <NUM>, then the process <NUM> proceeds to a third module <NUM> at which the process <NUM> determines whether the battery cooling load BCL is below another threshold Tmin that is set based on a minimum temperature for which the battery <NUM> is rated. In an example, the threshold Bmin is set at the minimum temperature for which the battery <NUM> is rated. In another example, the threshold Bmin is set a few (e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>) degrees above the minimum temperature for which the battery <NUM> is rated. At module <NUM>, the process <NUM> determines whether the ambient temperature Tamb is below a predetermined threshold Tmin. In an example, the threshold Tmin is set based on a temperature at which the air-cooled condenser <NUM> cools the coolant below the Bmin temperature threshold.

If the process <NUM> determines the battery cooling load BCL is within the thresholds Bmax and Bmin and determines the ambient temperature is within the temperature thresholds Tmax and Tmin, then the process <NUM> proceeds a set <NUM> of operations at which the electronic controller <NUM> operates the coolant circuits <NUM>, <NUM> and the refrigerant circuit <NUM> in a normal state. In certain examples, the operation set <NUM> includes a first operation <NUM> at which a percentage of coolant flow the valve <NUM> directs to the first condenser <NUM> is determined and set. In certain examples, the percentage of coolant flow is determined to be zero and the condenser routing path <NUM> is closed. In certain examples, the operation set <NUM> also includes a second operation <NUM> at which a speed of the compressor <NUM> is determined and set to provide sufficient cooling to the coolant of the battery cooling circuit <NUM>. In certain examples, the operation set <NUM> includes a third operation <NUM> at which a speed of the battery pump <NUM> is determined and set to provide adequate coolant flow past the battery <NUM> to sufficiently cool the battery <NUM> (e.g., to maintain a battery temperature between <NUM> and <NUM> degrees Celsius, between <NUM> and <NUM> degrees Celsius, between <NUM> and <NUM> degrees Celsius, between <NUM> and <NUM> degrees Celsius, etc.).

However, if the battery cooling load BCL is determined at module <NUM> to be greater than the threshold Bmax or if the ambient temperature Tamb is determined at module <NUM> to be greater than the threshold Tmax, then the process <NUM> proceeds to a first adjustment set <NUM> of operations at which the electronic controller <NUM> modifies operation of the refrigerant circuit <NUM>, the battery cooling circuit <NUM>, and/or the propeller arrangement cooling circuit <NUM> to increase the level of cooling provided to the battery <NUM>.

In certain implementations, the first adjustment set <NUM> of operations includes a first increase operation <NUM> at which the percentage flow of coolant directed to the liquid-cooled condenser <NUM> is increased. For example, the electronic controller <NUM> may actuate the valve <NUM> to begin directing coolant flow (or to increase coolant flow) to the liquid-cooled condenser <NUM>. In certain examples, the electronic controller <NUM> may increase a speed of the pump <NUM> to increase the flow rate past the liquid-cooled condenser <NUM>. Increasing the flow of coolant to the liquid-cooled condenser will increase the amount of cooling of the refrigerant at the liquid-cooled condenser <NUM> and hence enhance the efficiency of the refrigerant circuit <NUM>. Accordingly, the liquid-cooled condenser <NUM> may supplement cooling the refrigerant when a warm ambient temperature Tamb mitigates the amount of cooling provided by the air-cooled condenser <NUM>.

In certain implementations, the first adjust set <NUM> of operations also may include fluidly connecting the propeller arrangement cooling circuit <NUM> to the battery cooling circuit <NUM> to enhance the level of cooling provided to the liquid-cooled condenser <NUM>. For example, the electronic controller <NUM> may actuate the downstream valve arrangement <NUM> to fluidly couple the first coolant and the second coolant. Accordingly, the coolant cooling the liquid-cooled condenser <NUM> would be cooled both by the radiator <NUM> of the propeller arrangement cooling circuit <NUM> and also by the refrigeration circuit <NUM> at the chiller <NUM> of the battery cooling circuit <NUM>.

In certain implementations, the first adjustment set <NUM> of operations includes a second increase operation <NUM> at which the flow of refrigerant through the refrigeration circuit <NUM> is increased. For example, the electronic controller <NUM> may increase a speed of the compressor <NUM>. In certain implementations, the first adjustment set <NUM> of operations includes a third increase operation <NUM> at which a coolant flow through the battery cooling circuit <NUM> is increased. For example, the electronic controller <NUM> may increase the speed of the battery pump <NUM>. The process <NUM> returns to the determine operation <NUM> to check the temperatures again.

On the other hand, if the battery cooling load BCL is determined at module <NUM> to be less than the threshold Bmin or if the ambient temperature Tamb is determined at module <NUM> to be less than the threshold Tmin, then the process <NUM> proceeds to a second adjustment set <NUM> of operations at which the electronic controller <NUM> modifies operation of the refrigerant circuit <NUM>, the battery cooling circuit <NUM>, and/or the propeller arrangement cooling circuit <NUM> to decrease the level of cooling provided to the battery <NUM> and/or to the propeller arrangement <NUM>.

In certain implementations, the second adjustment set <NUM> of operations includes a first decrease operation <NUM> at which the percentage flow of coolant directed to the liquid-cooled condenser <NUM> is decreased. For example, the electronic controller <NUM> may actuate the valve <NUM> to reduce the amount of coolant directed to the liquid-cooled condenser <NUM>. In an example, the electronic controller <NUM> may actuate the valve <NUM> to close the condenser routing path <NUM> to cease coolant flow to the liquid-cooled condenser <NUM>. In such examples, the refrigerant would rely on air cooling by the condenser <NUM>.

Claim 1:
A thermal management system for an aircraft (<NUM>) including a propeller arrangement (<NUM>) and a battery (<NUM>) powering the propeller arrangement, the thermal management system (<NUM>) comprising:
a refrigeration circuit (<NUM>) including a compressor (<NUM>), a condenser arrangement (<NUM>), an expansion valve (<NUM>), and a chiller (<NUM>), the compressor being configured to route a refrigerant past the condenser arrangement and past the expansion valve to the chiller, the condenser arrangement including an air-cooled condenser (<NUM>) exposed to ambient temperature air outside the aircraft and a liquid-cooled condenser (<NUM>);
a battery cooling circuit (<NUM>) configured to route first coolant past the battery of the aircraft, the battery cooling circuit including a first tank (<NUM>), a first pump (<NUM>), and the chiller, the first pump being configured to direct the first coolant from the first tank, past the battery at which heat is absorbed by the first coolant, to the chiller at which heat is rejected from the first coolant to the refrigerant; and
a propeller arrangement cooling circuit (<NUM>) configured to cool the propeller arrangement of the aircraft using second coolant drawn from a second tank (<NUM>) by a second pump (<NUM>), the propeller arrangement cooling circuit including a radiator arrangement (<NUM>) exposed to the ambient temperature air,
wherein the propeller arrangement cooling circuit (<NUM>) is configured to direct the second coolant drawn from the second tank to the propeller arrangement and/or along a condenser routing path (<NUM>) to the liquid-cooled condenser, and the radiator arrangement is disposed downstream of the liquid-cooled condenser.