Patent Description:
In particular the disclosure is concerned with a thermodynamic apparatus provided as a heat engine or heat pump.

A heat engine is a system that converts heat energy to mechanical energy, which can then be used to do mechanical work. It does this by changing a working fluid from a higher state temperature to a lower state temperature. The working fluid generates work in the working body of the engine while transferring heat to a heat sink. During this process some of the thermal energy is converted into work.

A heat pump is transfers heat energy from a source of heat to a thermal reservoir. Thermal energy is absorbed from a cold space and delivered to a warmer one. To achieve this work must be done on the working fluid of the device - for example, a motor may be used to drive the heat exchange to transfer energy from the heat source to the heat sink.

Although not appropriate to all applications, heating or cooling may be achieved between compressor/turbine rotor stages of a heat engine or heat pump by mixing working gas flows, although this is limited by the availability of working fluid available downstream of the compressor and/or turbine. Alternatively heat transfer may be achieved by passing working fluid through a heat exchanger external to the turbine and/or compressor, which adds to size and complexity of the apparatus. All of these methods are aimed to add additional heat to expanded working fluid downstream of a turbine rotor stage, or remove heat from compressed working fluid downstream of the compressor rotor stage.

However, all the systems have the demerit of being limited to the availability of working fluid passing through the apparatus, or require bulky apparatus (for example external heat exchangers external to the turbine and/or compressor) which take up an undesirable amount of space and inherently introduce losses to the system by virtue of inevitable heat transfer to/from the environment surrounding the apparatus. These are significant considerations for applications such as use in power generation or power storage systems, especially where they are provided on vehicles including, but not limited to, vessels (e.g. boats or ships).

<CIT>); <CIT>); <CIT>), <CIT>); and <CIT> describe examples of the related art.

Hence a system which increases the thermal efficiency of a heat engine, but allows it to be of a compact size compared to examples of the related art, is highly desirable.

According to the present disclosure there is provided a thermodynamic apparatus as set forth in the appended claims.

Accordingly there is provided a thermodynamic apparatus (<NUM>) comprising a compressor module (<NUM>), a turbine module (<NUM>), and a regenerative heat exchanger (<NUM>) centred on a central axis (<NUM>). The compressor module (<NUM>), turbine module (<NUM>), and regenerative heat exchanger (<NUM>) is arranged in series along the central axis (<NUM>) such that the regenerative heat exchanger (<NUM>) is provided between the compressor module (<NUM>) and the turbine module (<NUM>).

The thermodynamic apparatus (<NUM>) may further comprise a shaft (<NUM>) centred on, and rotatable about, the central axis (<NUM>). The shaft (<NUM>) may extend through the compressor module (<NUM>), the turbine module (<NUM>), and regenerative heat exchanger (<NUM>). The compressor module (<NUM>) may comprise a rotor (<NUM>). The turbine module (<NUM>) may comprise a rotor (<NUM>). Both rotors (<NUM>, <NUM>) may be carried on and rotatable with the shaft (<NUM>).

The thermodynamic apparatus (<NUM>) further comprises a casing (<NUM>), wherein the casing (<NUM>) extends around the compressor module (<NUM>), turbine module (<NUM>), and a regenerative heat exchanger (<NUM>).

The compressor module (<NUM>), a turbine module (<NUM>), and a regenerative heat exchanger (<NUM>) define a working fluid flow duct (<NUM>) which extends, in series, through : a compressor module inlet (<NUM>) to a compressor module outlet (<NUM>); a first path (<NUM>) through the regenerative heat exchanger (<NUM>); a turbine module inlet (<NUM>) to the turbine module outlet (<NUM>); a first intermediate duct (<NUM>); a second path (<NUM>) through the regenerative heat exchanger (<NUM>), which is in heat transfer communication with the first path (<NUM>); and
a second intermediate duct (<NUM>) to the compressor module inlet (<NUM>).

The compressor module (<NUM>) may defines a first portion (<NUM>) of the working fluid flow duct (<NUM>) which extends between the compressor module inlet (<NUM>) and the compressor module outlet (<NUM>). The compressor module (<NUM>) may comprise : a first heat exchanger (<NUM>) and the compressor rotor (<NUM>), each provided in the working fluid flow duct (<NUM>). The first heat exchanger (<NUM>) may be provided in flow series between the compressor module inlet (<NUM>) and the compressor rotor (<NUM>). The compressor rotor (<NUM>) may be provided in flow series between the first heat exchanger (<NUM>) and the compressor module outlet (<NUM>). There may also be provided a heat transfer unit (<NUM>) which defines the first portion (<NUM>) of the working fluid flow duct (<NUM>). The first heat exchanger (<NUM>) may be in heat transfer communication with the heat transfer unit (<NUM>) via a first main passage (<NUM>) for a first heat transfer medium. The first heat exchanger (<NUM>) may be configured such that it is operable to transfer heat to the heat transfer unit (<NUM>) from the working fluid passing the first heat exchanger (<NUM>).

The turbine module (<NUM>) may define a second portion (<NUM>) of the working fluid flow duct (<NUM>) which extends between a turbine module inlet (<NUM>) and a turbine module outlet (<NUM>) configured to expand a working fluid as the working fluid passes along the working fluid flow duct (<NUM>). The turbine module may comprise : a first heat exchanger (<NUM>) and a turbine rotor (<NUM>), each provided in the working fluid flow duct (<NUM>); the first heat exchanger (<NUM>) provided in flow series between the turbine module inlet (<NUM>) and the turbine rotor (<NUM>). The turbine rotor (<NUM>) may be provided in flow series between the first heat exchanger (<NUM>) and the turbine module outlet (<NUM>). There may also be provided a heat transfer unit (<NUM>) which defines a portion (<NUM>) of the working fluid flow duct (<NUM>) in flow series between the turbine rotor (<NUM>) and turbine module outlet (<NUM>). The first heat exchanger (<NUM>) may be in heat transfer communication with the heat transfer unit (<NUM>) via a second main passage (<NUM>) for a second heat transfer medium, and the first heat exchanger (<NUM>) is configured such that it is operable to transfer heat received from the heat transfer unit (<NUM>) to the working fluid passing the first heat exchanger (<NUM>).

The first main passage (<NUM>) and second main passage (<NUM>) may each comprise an inlet plenum (<NUM>, <NUM>) and an outlet plenum (<NUM>, <NUM>), and the inlet plenum (<NUM>) and outlet plenum (<NUM>) of the compressor (<NUM>) may be in fluid flow communication via a compressor first sub-passage (<NUM>) defined by the compressor heat transfer unit (<NUM>) for the transfer of the respective heat transfer medium through the compressor first heat exchanger (<NUM>). The inlet plenum (<NUM>) and outlet plenum (<NUM>) of the turbine (<NUM>) are in fluid flow communication via a turbine first sub-passage (<NUM>) defined by the turbine heat transfer unit (<NUM>) for the transfer of the respective heat transfer medium through the turbine first heat exchanger (<NUM>). Each inlet plenum (<NUM>, <NUM>) may have an inlet (<NUM>, <NUM>) for communication with a different source of heat transfer medium.

Each outlet plenum (<NUM>, <NUM>) may have an outlet (<NUM>, <NUM>) to exhaust the respective heat transfer medium.

The first sub-passage (<NUM>, <NUM>) may extend through the first heat exchanger (<NUM>, <NUM>). The first heat exchanger (<NUM>, <NUM>) may be in flow series between a first inlet (<NUM>, <NUM>) to the first sub-passage (<NUM>, <NUM>) and a first outlet (<NUM>, <NUM>) from the first sub-passage (<NUM>, <NUM>). The the first inlet (<NUM>, <NUM>) may be configured to receive heat transfer medium from the inlet plenum (<NUM>, <NUM>); the first outlet (<NUM>) being configured to exhaust into the outlet plenum (<NUM>, <NUM>).

A second heat exchanger (<NUM>) may be located in the working fluid flow duct (<NUM>) in flow series between the compressor rotor (<NUM>) and the compressor module outlet (<NUM>) in the heat transfer unit (<NUM>). The second heat exchanger (<NUM>) may be configured such that it is operable to transfer heat to the heat transfer unit (<NUM>) from the working fluid passing the second heat exchanger (<NUM>).

A second heat exchanger (<NUM>) may be located in the working fluid flow duct (<NUM>) in flow series between the turbine rotor stage (<NUM>) and the turbine module outlet (<NUM>) in the heat transfer unit (<NUM>). The second heat exchanger (<NUM>) may be configured such that it is operable to transfer heat received from the heat transfer unit (<NUM>) to the working fluid passing the second heat exchanger (<NUM>).

The first sub-passage (<NUM>, <NUM>) may extend through the second heat exchanger (<NUM>, <NUM>).

A second sub-passage (<NUM>, <NUM>) may extend through the second heat exchanger (<NUM>, <NUM>); and the second heat exchanger (<NUM>, <NUM>) is in flow series between a second inlet (<NUM>, <NUM>) to the second sub-passage (<NUM>, <NUM>) and a second outlet (<NUM>, <NUM>) from the second sub-passage (<NUM>, <NUM>). The second inlet (<NUM>, <NUM>) may be configured to receive heat transfer medium from the inlet plenum (<NUM>, <NUM>). The second outlet (<NUM>, <NUM>) may be configured to exhaust into the outlet plenum (<NUM>, <NUM>).

The first heat exchanger (<NUM>, <NUM>) may be provided in series along the first sub-passage (<NUM>, <NUM>) between the first inlet (<NUM>) and the second heat exchanger (<NUM>, <NUM>), and the second heat exchanger (<NUM>, <NUM>) may be provided in flow series between the first heat exchanger (<NUM>, <NUM>) and the first outlet (<NUM>, <NUM>) from the first heating medium flow sub-passage (<NUM>, <NUM>).

The first sub-passage (<NUM>, <NUM>) may comprise a first node (<NUM>) between the first inlet (<NUM>, <NUM>) and the first heat exchanger (<NUM>, <NUM>) where the sub-passage diverges to form a first branch (<NUM>) and second branch (<NUM>). There may also be provided a second node (<NUM>) between the outlet (<NUM>, <NUM>) and the second heat exchanger (<NUM>, <NUM>) where the first branch (<NUM>) and second branch (<NUM>) join. The first branch (<NUM>) of the first sub-passage (<NUM>,<NUM>) may extend through the first heat exchanger (<NUM>, <NUM>) and bypasses the second heat exchanger (<NUM>, <NUM>). The second branch (<NUM>) may bypass the first heat exchanger (<NUM>, <NUM>) and extend though the second heat exchanger (<NUM>, <NUM>).

The first sub-passage (<NUM>, <NUM>) may comprise a third sub-passage (<NUM>, <NUM>) which extends from a second inlet (<NUM>, <NUM>) in fluid communication with the inlet plenum (<NUM>, <NUM>) through the second heat exchanger (<NUM>, <NUM>). The third sub-passage may join the first sub-passage (<NUM>,<NUM>) between the outlet of the first heat exchanger (<NUM>, <NUM>) and first sub-passage outlet (<NUM>, <NUM>); such that flow through the first inlet (<NUM>, <NUM>) and second inlet (<NUM>, <NUM>) exit through the first outlet (<NUM>, <NUM>).

Hence there may be provided a heat engine of increased thermal efficiency and power output which has lower running costs compared to examples of the related art. There may also be provided a heat pump of increased thermal efficiency, with lower power requirements and hence lower running costs compared to examples of the related art. Hence a heat engine or heat pump according to the present disclosure may be smaller and cheaper than examples of the related art having similar capacity, giving a significant competitive advantage.

The present disclosure relates to a closed loop heat engine or heat pump system comprising a compressor system and/or a turbine system of the present disclosure. In operation a working fluid is passed through the compressor and turbine. At the same time, a compressor heat transfer medium (for example a coolant for removal of heat from the working fluid in the compressor) is passed through the body of the compressor module, and a turbine heat transfer medium (for example a heating medium for addition of heat to the working fluid in the turbine) is passed through the body of the turbine module.

A thermodynamic apparatus comprising the turbine system and compressor system of the present disclosure may be used in power generation applications using regenerative, reheated, intercooled closed cycle turbo machinery. A turbine module of the present disclosure may be operable to approximate isothermal expansion. A compressor of the present disclosure may approximate isothermal compression. Hence the turbine module and compressor module may be included into a heat engine based on a closed cycle gas turbine arrangement for producing power from a heat source. This arrangement of equipment may provide a heat engine which operates in a manner approximating the Ericsson thermodynamic cycle. Hence the thermodynamic apparatus may be provided a closed cycle gas turbine that may be driven by a heated fluid source and a cooled fluid source to rotate a shaft, and hence provide a power output.

A thermodynamic apparatus comprising the turbine system and compressor system of the present disclosure may be used in refrigeration applications (i.e. to operate as a heat pump). Hence the thermodynamic apparatus may be provided a closed cycle gas turbine that may be driven by a motor to provide a power input, and hence move heat from a heat source to a heat sink.

The apparatus of the present disclosure may also include equipment operable to control, start and stop and seal the machinery. The present disclosure may also relate to a method of manufacture and assembly of a compressor, turbine and regenerative heat exchanger according to the present disclosure.

<FIG> shows a schematic representation of a thermodynamic apparatus <NUM> (which may be configured as a heat engine or heat pump) including a cooled compressor <NUM>, a heated turbine <NUM>, a fluid heater <NUM> (configured to be in heat flow communication with a heat source), a fluid cooler <NUM> (configured to be in heat flow communication with a heat sink) and a recuperator (heat exchanger) <NUM> to create the thermodynamic apparatus <NUM>.

As a heat engine, this can be used to drive a generator <NUM>, or alternatively a propulsion shaft and propeller, a compressor, pumps or other power consuming equipment. It can also power combinations of these items. As a heat pump, power is input into the shaft. Both may comprise turbine inter-stage heating and a nozzle heater, and a compressor with cooled diaphragm blading and inter-stage cooling according to the present disclosure herein described. It provides a heat engine or heat pump with extremely high thermodynamic efficiency, and a simple design which can be manufactured using the components as described.

Heat sources can include but are not limited to: burning fuel, reactors, thermal solar and/or geothermal.

In <FIG> the heater fluid supply and return, and cooler fluid supply and return pipework, is shown as a single line for illustration purposes only. Each of these pipes can pass through a manifold, and split into the many supply and return lines to provide fluid at the same temperature to each heating or cooling element.

As presented in <FIG>, <FIG>, a thermodynamic apparatus <NUM> according to the present disclosure comprises a compressor module <NUM>, a turbine module <NUM>, and a regenerative heat exchanger <NUM> centred on a central axis <NUM>. The compressor module <NUM>, a turbine module <NUM>, and a regenerative heat exchanger <NUM> are arranged in series along the central axis <NUM> such that the regenerative heat exchanger <NUM> is provided between the compressor module <NUM> and the turbine module <NUM>. As shown in <FIG>, <FIG>, the regenerative heat exchanger <NUM> defines two flow paths <NUM>, <NUM>. The first flow path <NUM> is operable to deliver working fluid from the compressor module <NUM> to the turbine module <NUM>, and the second flow path <NUM> is operable to deliver working fluid from the turbine module <NUM> to the compressor module <NUM>. The paths <NUM>, <NUM> are in heat transfer communication with one another. That is to say, the first flow path <NUM> and second flow path <NUM> are configured so that heat energy may be transferred between them. For example, the flow paths <NUM>, <NUM> may be adjacent one another, divided by a wall with an appropriate heat transfer characteristic.

The regenerative heat exchanger <NUM> may be configured to be counter flow. That is to say, the first flow path <NUM> and second flow path <NUM> may be arranged such that working fluid flows in a first direction along the first flow path <NUM> from the compressor module <NUM> to the turbine module <NUM>, and in a second direction along the second flow path <NUM> from the turbine module <NUM> to the compressor module <NUM>. Hence the first direction may be opposite to the second direction, such that a counter flow is provided.

In an example in which the thermodynamic apparatus is a heat engine the regenerative heat exchanger <NUM> is operable (i.e. configured to) transfer heat energy from the second path <NUM> to the first path <NUM>, and thereby transfer energy from the working fluid in the second path <NUM> (i.e. working fluid being delivered from the turbine module <NUM> to the compressor module <NUM>) to the working fluid in the first path <NUM> (i.e. working fluid being delivered from the compressor module <NUM> to the turbine module <NUM>). In an example in which the thermodynamic apparatus is a heat pump, the regenerative heat exchanger <NUM> is operable (i.e. configured to) transfer heat energy from the first path <NUM> to the second path <NUM>, and thereby transfer energy from the working fluid in the first path <NUM> (i.e. working fluid being delivered from the compressor module <NUM> to the turbine module <NUM>) to the working fluid in the second path <NUM> (i.e. working fluid being delivered from the turbine module <NUM> to the compressor module <NUM>).

The regenerative heat exchanger <NUM> may have a design of simple construction using a low number of simple parts (minimum of three, shown assembled in <FIG>) which can be manufactured using common manufacturing techniques (machining, forging, casting, additive manufacture) ensuring low cost. The design also allows for a high surface area (increasing heat exchange and efficiency), low flow friction losses and for the channels in each side of the working fluid to be optimised in shape and size to achieve an efficient heat transfer with minimal flow losses. The main components include two heat exchanger plates (<FIG>) and a flow guide (<FIG>).

The apparatus further comprises a shaft <NUM> centred on, and rotatable about, the central axis <NUM>. The shaft <NUM> extends through the compressor module <NUM>, the turbine module <NUM>, and regenerative heat exchanger <NUM>. The compressor module <NUM> comprises at least one rotor <NUM> (i.e. compressor rotor stage). The turbine module <NUM> comprises at least one rotor <NUM> (i.e. turbine rotor stage). Both rotors <NUM>, <NUM> are carried on and rotatable with the shaft <NUM>.

Each of the compressor module <NUM>, turbine module <NUM>, and regenerative heat exchanger <NUM> are enclosed by a common casing <NUM>. Hence the thermodynamic apparatus <NUM> further comprises a casing <NUM>. As shown in <FIG>, the casing <NUM> extends around the compressor module <NUM>, turbine module <NUM>, and regenerative heat exchanger <NUM>.

Also as shown in <FIG>, the casing <NUM> may be substantially cylindrical. That is to say, the casing <NUM> may be substantially cylindrical along its length. Put another way, the casing <NUM> may have an external surface which extends parallel to the central axis <NUM> along the length of the casing <NUM>. One or both ends of the casing <NUM> may be provided with a flange <NUM> for connection with an end plate <NUM>.

In an alternative example the casing <NUM> may have different alternative external geometry, while still enclosing all of the compressor module <NUM>, turbine module <NUM>, and regenerative heat exchanger <NUM>.

The casing <NUM> may be provided as a casing assembly. Hence the casing may comprise at least two modules (i.e. elements, pieces or segments) which are assembled to form the casing <NUM>.

The arrangements shown in <FIG> show variations of the design shown in <FIG>. In these the relative position of the compressor module <NUM>, turbine module <NUM>, regenerative heat exchanger <NUM> and casing <NUM> are shown.

As will be described, the compressor module <NUM> comprises heat exchangers to cool working fluid passing therethrough, and the turbine module <NUM> comprises heat exchangers to heat working fluid passing therethrough.

In <FIG> the low pressure side of the working fluid is contained next to the casing <NUM> and in a working fluid return channel. In <FIG> the high pressure fluid is next to the casing and in the working fluid return channel.

<FIG> shows an example of the thermodynamic apparatus <NUM> when assembled, and <FIG> shows the apparatus <NUM> with the casing <NUM> removed. In use, the casing <NUM> is pressurised, and a closed cycle loop is defined by the compressor module <NUM>, a regenerative heat exchanger <NUM> and turbine module <NUM>.

As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG> the compressor module <NUM>, a turbine module <NUM>, and a regenerative heat exchanger <NUM> define a working fluid flow duct <NUM>. The working fluid flow duct <NUM> defines a closed loop, and hence is configured to be a closed cycle system. The working fluid flow duct <NUM> extends, in series, through a compressor module inlet <NUM> to a compressor module outlet <NUM>; the first path <NUM> through the regenerative heat exchanger <NUM>; a turbine module inlet <NUM> to the turbine module outlet <NUM>; a first intermediate duct <NUM> provided in (i.e. defined by) the turbine module <NUM>; the second path <NUM> through the regenerative heat exchanger <NUM>, which is in heat transfer communication with the first path <NUM>; a second intermediate duct <NUM> provided in (i.e. defined by) the compressor module <NUM>, which leads back to the compressor module inlet <NUM>.

In the example shown in <FIG>, <FIG> the thermodynamic apparatus comprises a compressor module <NUM> made up of two compressor stages arranged in series, and a turbine module <NUM> made up of two turbine stages. Each stage comprises a respective rotor <NUM>, <NUM> and a first heat exchanger <NUM>, <NUM>. In some examples, not shown, the compressor module <NUM> may comprise a single compressor stage, and the turbine module <NUM> may comprise a single turbine stage. Hence in the description reference to the compressor or turbine module inlet or outlet may refer to the module assembly as whole (as shown in <FIG>, <FIG>, where the compressor inlet <NUM> is the inlet to the whole compressor module assembly, and the outlet <NUM> is the outlet for the whole compressor assembly, and the turbine inlet <NUM> is the inlet to the whole turbine module assembly, and the outlet <NUM> is the outlet for the whole turbine assembly) or to a region in the working flow duct <NUM> which defines the end of one stage and the beginning of another (as shown in <FIG>, <FIG>, <FIG> where the compressor module/stage inlet <NUM> is shown upstream of the first heat exchanger <NUM> and the compressor module/stage outlet <NUM> is shown downstream of the second heat exchanger <NUM>.

The regenerative heat exchanger <NUM> may comprise a single stage, for example as shown in <FIG>, <FIG>, or may comprise a plurality of stages (for example two stages) as shown in the example of <FIG>. Hence an example comprising a plurality of stages may be operable to increase the amount of heat transferred to the working fluid passing through the working fluid flow duct <NUM>.

As illustrated in <FIG>, the compressor module <NUM> defines a first portion <NUM> of the working fluid flow duct <NUM>. The first portion <NUM> extends between the compressor module inlet <NUM> and the compressor module outlet <NUM>. In the example shown the first portion comprises two compressor modules <NUM>. As shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, each stage of the compressor module <NUM> comprises a first heat exchanger <NUM> and the compressor rotor <NUM>, each being provided in the working fluid flow duct <NUM>. The first heat exchanger <NUM> is provided in flow series between the compressor module inlet <NUM> and the compressor rotor <NUM>. The compressor rotor <NUM> is provided in flow series between the first heat exchanger <NUM> and the compressor module outlet <NUM>. The first heat exchanger <NUM> is defined by a wall <NUM> having an external surface <NUM> which is located in the working fluid flow duct <NUM>. A heat transfer unit <NUM> defines the first portion <NUM> of the working fluid flow duct <NUM>. The first heat exchanger <NUM> is in heat transfer communication with the heat transfer unit <NUM> via a first main passage <NUM> for a first heat transfer medium (i.e. a coolant). The first heat exchanger <NUM> is configured such that it is operable to transfer heat to the heat transfer unit <NUM> from the working fluid passing the first heat exchanger <NUM>.

The turbine module <NUM> defines a second portion <NUM> of the working fluid flow duct <NUM> which extends between a turbine module inlet <NUM> and a turbine module outlet <NUM>. The turbine module <NUM> is configured to expand a working fluid as the working fluid passes along the working fluid flow duct <NUM>. Each stage of the turbine module <NUM> comprises a first heat exchanger <NUM> and the turbine rotor <NUM>, each being provided in the working fluid flow duct <NUM>. The first heat exchanger <NUM> is provided in flow series between the turbine module inlet <NUM> and the turbine rotor <NUM>. The turbine rotor <NUM> is provided in flow series between the first heat exchanger <NUM> and the turbine module outlet <NUM>. The first heat exchanger <NUM> is defined by a wall <NUM> having an external surface <NUM> which is located in the working fluid flow duct <NUM>. A heat transfer unit <NUM> defines a portion <NUM> of the working fluid flow duct <NUM> in flow series between the turbine rotor <NUM> and turbine module outlet <NUM>. The first heat exchanger <NUM> is in heat transfer communication with the heat transfer unit <NUM> via a second main passage <NUM> for a second heat transfer medium.

The first heat exchanger <NUM> is configured such that it is operable to transfer heat received from the heat transfer unit <NUM> to the working fluid passing the first heat exchanger <NUM>.

As shown in figures, the working fluid flow duct <NUM> may be serpentine. That is to say the working fluid flow duct may comprise a plurality of sections which extend at an angle, for example at a right angle, to the central rotational axis <NUM>. Put another way, the working fluid flow duct <NUM> may comprise a number of sections which extend radially relative to the central rotational axis <NUM>. The radially extending sections may be joined by longitudinally extending or curved sections. That is to say the radially extending sections may be linked to one another by further sections which extend in a direction which has a component which extends parallel to the central axis <NUM>. These further/joining sections are in part defined by the rotor stages <NUM>, <NUM>. The heat exchangers <NUM>, <NUM>, <NUM>, <NUM> are located in the radially extending sections of the working fluid flow duct <NUM>. Providing the working fluid flow duct <NUM> with a serpentine configuration means that the surface area of the working fluid flow duct <NUM> may be maximised for the length of the apparatus <NUM>.

The working fluid flow duct <NUM> may have such a serpentine flow route through each of the compressor stage(s), turbine stage(s) and regenerative heat exchanger stage(s).

As shown in <FIG>, <FIG>, <FIG>, <FIG> the first main passage <NUM> of the compressor module <NUM> and second main passage <NUM> of the turbine module <NUM> each comprise an inlet plenum <NUM>, <NUM> and an outlet plenum <NUM>, <NUM>. The inlet plenum <NUM> and outlet plenum <NUM> of the compressor <NUM> are in fluid flow communication via a compressor first sub-passage <NUM> defined by the compressor heat transfer unit <NUM> for the transfer of the respective heat transfer medium through the compressor first heat exchanger <NUM>. The inlet plenum <NUM> and outlet plenum <NUM> of the turbine <NUM> are in fluid flow communication via a turbine first sub-passage <NUM> defined by the turbine heat transfer unit <NUM> for the transfer of the respective heat transfer medium through the turbine first heat exchanger <NUM>.

Each inlet plenum <NUM>, <NUM> has an inlet <NUM>, <NUM> for communication with a different source of heat transfer medium, and each outlet plenum <NUM>, <NUM> has an outlet <NUM>, <NUM> to exhaust the respective heat transfer medium. That is to say, the compressor inlet plenum <NUM> has an inlet <NUM> for communication with a source of a heat transfer medium which is a cooling medium (i.e. a coolant) and the compressor outlet plenum <NUM> has an outlet <NUM> to exhaust the coolant from the first main passage <NUM>. Likewise the turbine inlet plenum <NUM> has an inlet <NUM> for communication with a source of heating medium (for example a heated fluid), and the turbine outlet plenum <NUM> has an outlet <NUM> to exhaust the heating medium from the second main passage <NUM>.

As shown in <FIG>, <FIG>, <FIG> the first sub-passages <NUM>, <NUM> of the compressor module and turbine module extend through the first heat exchanger <NUM>, <NUM>. <FIG> shows an alternative arrangement to that shown in <FIG>, and may be applied to the compressor module and/or turbine module heat exchangers. <FIG> shows a sectional view of a compressor <NUM> and/or turbine <NUM> according to the present invention. That is to say, the compressor <NUM> and turbine <NUM> may have the same features as one another, and the features are indicated in <FIG> using reference numerals of the compressor <NUM> and turbine <NUM>. In <FIG>, <FIG>, <FIG> the top half of the figure relate to the turbine module <NUM> (with flow through the working fluid flow duct <NUM> being from left to right), and the bottom half of the figures relate to the compressor module <NUM> (with flow through the working fluid flow duct <NUM> being from right to left). The first heat exchanger <NUM>, <NUM> is in flow series between a first inlet <NUM>, <NUM> to the first sub-passage <NUM>, <NUM> and a first outlet <NUM> from the first sub-passage <NUM>, <NUM>. The first inlet <NUM>, <NUM> is configured to receive heat transfer medium from the inlet plenum <NUM>, <NUM>. The first outlet <NUM>, <NUM> is configured to exhaust into the outlet plenum <NUM>, <NUM>.

As shown in <FIG>, <FIG> each stage of the compressor module <NUM> may comprise a second heat exchanger <NUM> located in the working fluid flow duct <NUM> in flow series between the compressor rotor <NUM> and the compressor module outlet <NUM> in the heat transfer unit <NUM>. The compressor second heat exchanger <NUM> is defined by a wall <NUM> having an external surface <NUM> which is located in the working fluid flow duct <NUM>. The second heat exchanger <NUM> is configured such that it is operable to transfer heat to the heat transfer unit <NUM> from the working fluid passing the second heat exchanger <NUM>.

Each stage of the turbine module <NUM> may comprise a second heat exchanger <NUM> which is located in the working fluid flow duct <NUM> in flow series between the turbine rotor stage <NUM> and the turbine module outlet <NUM> in the heat transfer unit <NUM>. The compressor second heat exchanger <NUM> defined by a wall <NUM> having an external surface <NUM> which is located in the working fluid flow duct <NUM>. The second heat exchanger <NUM> is configured such that it is operable to transfer heat received from the heat transfer unit <NUM> to the working fluid passing the second heat exchanger <NUM>.

Hence since a compressor module <NUM> and a turbine module <NUM> may comprise multiple stages, there may be several pairs of first heat exchangers and second heat exchangers in the working fluid flow duct <NUM> defined by each of the compressor module and turbine module. In an alternative example the compressor module and turbine module may comprise a single stage, in which case only a first heat exchanger and second heat exchanger may be provided in the section of the working fluid flow duct <NUM> which extends through each of the compressor module <NUM> and turbine module <NUM>.

In each of the compressor module <NUM> and turbine module <NUM> the first sub-passage <NUM>, <NUM> extends through the second heat exchanger <NUM>, <NUM>.

As shown in the example of <FIG>, in each of the compressor module <NUM> and turbine module <NUM> a second sub-passage <NUM>, <NUM> extends through the second heat exchanger <NUM>, <NUM>. The second heat exchanger <NUM>, <NUM> is in flow series between a second inlet <NUM>, <NUM> to the second sub-passage <NUM>, <NUM> and a second outlet <NUM>, <NUM> from the second sub-passage <NUM>, <NUM>. The second inlet <NUM>, <NUM> is configured to receive heat transfer medium from the inlet plenum <NUM>, <NUM>. The second outlet <NUM>, <NUM> is configured to exhaust into the outlet plenum <NUM>, <NUM>.

In each of the compressor module <NUM> and turbine module the first heat exchanger <NUM>, <NUM> is provided in series along/in the first sub-passage <NUM>, <NUM> between the first inlet <NUM>, <NUM> and the second heat exchanger <NUM>, <NUM>, and the second heat exchanger <NUM>, <NUM> is provided in flow series between the first heat exchanger <NUM>, <NUM> and the first outlet <NUM>, <NUM> from the first heating medium flow sub-passage <NUM>, <NUM>.

As shown in an alternative example of <FIG> the first sub-passage <NUM>, <NUM> may comprise a first node <NUM> between the first inlet <NUM>, <NUM> and the first heat exchanger <NUM>, <NUM> where the sub-passage splits/diverges to form a first branch <NUM> and second branch <NUM>. A second node <NUM> is provided between the outlet <NUM>, <NUM> and the second heat exchanger <NUM>, <NUM> where the first branch <NUM> and second branch <NUM> join. The first branch <NUM> of the first sub-passage <NUM>,<NUM> extends through the first heat exchanger <NUM>, <NUM> and bypasses the second heat exchanger <NUM>, <NUM>. The second branch <NUM> bypasses the first heat exchanger <NUM>, <NUM> and extends though the second heat exchanger <NUM>, <NUM>.

As shown in an alternative example of <FIG> the first sub-passage <NUM>, <NUM> may comprise a third sub-passage <NUM>, <NUM> which extends from a second inlet <NUM>, <NUM> in fluid communication with the inlet plenum <NUM>, <NUM> through the second heat exchanger <NUM>, <NUM>. The third sub-passage <NUM>, <NUM> joins the first sub-passage <NUM>,<NUM> between the outlet of the first heat exchanger <NUM>, <NUM> and first sub-passage outlet <NUM>, <NUM> such that flow through the first inlet <NUM>, <NUM> and second inlet <NUM>, <NUM> exit through the first outlet <NUM>, <NUM>.

In <FIG> the connection to the plenums <NUM>, <NUM> and <NUM><NUM> is indicated with arrows, which indicates that at the inlets and outlets to the sub- passages there is a fluid connection to the plenums.

<FIG> shows a 3d image of the heat exchange module in <FIG> - heat exchange fluid is supplied and returned from a single supply and return which simplifies the heating and cooling supplies at the expense of efficiency.

<FIG> shows an alternative exploded view of a compressor module of the thermodynamic apparatus, although equally applies to a turbine module. It shows flow paths through and defined by a casing section <NUM>, working fluid flow guide <NUM> and sections of the heat transfer unit <NUM>. The first inlet <NUM> to the first sub-passage <NUM> and first outlet <NUM> are shown.

A key feature of the design is that plates are used to create the heat exchangers. For example, two machined inner casing plates are used to create a single sealing face, which is clamped together using a bolted joint arrangement. The internal surface / volume of this pair of plates hold the heat transfer fluid, with a single sealing surface. The plates clamp around a flow path guide assembly. This fits within slotted holes which define heat exchangers and restricts the flow of the heat transfer fluid to the optimum path through the space. This can be made up from a single flat plate, with a number of slotted holes which a number of shaped guide plates fit into, or a single machined or 3d printed item. When connected together these three plates create a heat exchanger with the heat transfer fluid contained within the inner casing plates.

<FIG> shows a sectional view of a heat exchanger assembly of the thermodynamic apparatus shown in <FIG>. In this example three cross-linked internal heat transfer flow passages are provided, so only one supply and return is required, for example as shown in <FIG>.

<FIG> shows a sectional view of a regenerative heat exchanger of the thermodynamic apparatus. <FIG> shows one half of the regenerative heat exchanger assembly. Rounded edges are shown on the inlet / outlet of the low pressure side slots which improve air flow.

<FIG> show different elements of the compressor, turbine and plenum structure of the thermodynamic apparatus. <FIG> show possible combined structural support arrangements and components which make up the supply and return plenum detailed as parts <NUM>, <NUM>, <NUM> and <NUM>. This provides support to the compressor and turbine structure and also a means of simple manufacture of the support assembly.

In <FIG> there is shown supply and return <NUM> of hot and cold heat exchange fluid. Also shown is a return <NUM> for seal leak / control line and a sliding seal <NUM> for supply and return.

In <FIG> there is shown a support structure <NUM> for the internal stages.

In <FIG> is shown internal restraints <NUM>. <FIG> shows a possible arrangement where there are multiple plenums to allow for increased heat transfer fluid flow. It also allows for the return of fluid from the seal drains. The seal drains allow leaking fluid to be captured and re-used.

In <FIG> is shown alternative arrangements <NUM> for supply and return of heat transfer fluids.

For simplicity, only barrel type arrangements are shown but equivalent horizontal and vertical split casing designs are possible to allow for assembly.

<FIG> shows a sealing arrangement of use in the apparatus of the present disclosure.

<FIG> shows a sectional view of the thermodynamic apparatus shown in <FIG>. <FIG> shows a cross section with a horizontal rather than vertical split in the turbine and compressor casing.

<FIG> shows detailed views of a regenerative heat exchanger which forms a part of the thermodynamic apparatus.

<FIG> illustrate example components of the regenerative heat exchanger shown in <FIG>.

<FIG> shows an example component of the regenerative heat exchanger shown in <FIG>.

<FIG> shows an alternative arrangement which can be used to support a set of multiple heat exchanger assemblies, for insertion into a barrel type casing. An arrangement of long studs or bolts <NUM> pass through all of the plates. Dowels which link the plate faces (in shear) allow for the casing to be accurately assembled.

The thermodynamic apparatus may be configured to operate as a heat engine. With reference to <FIG>, <FIG>, <FIG>, in use, the operation of the thermodynamic apparatus involves coupling the inlet plenum <NUM> to a heat sink (e.g. source of cold fluid) and the coupling of the inlet plenum <NUM> a heat source, so that each are supplied with a heat transfer fluid/medium. The heat transfer fluid in the first main passage <NUM> must be provided to be colder than the heat transfer fluid in the second main passage <NUM>. The outlet plenum <NUM> in outlet plenum <NUM> may exhaust back to the heat sink and heat source respectively, or maybe the directed elsewhere. A working fluid is provided in the working fluid flow duct <NUM>.

The different heat transfer fluid fluids are pumped from their source, through the main passages <NUM>, <NUM> and leave the apparatus. This temperature differential causes the flow of the working fluid through the working fluid flow duct <NUM>.

The working fluid will travel around the working fluid flow duct <NUM> from the compressor module inlet <NUM>, through the compressor module <NUM> to the compressor module outlet <NUM>, then through the first path <NUM> through the regenerative heat exchanger <NUM>, then through the turbine module inlet <NUM>, through the turbine module <NUM> to the turbine module outlet <NUM>, then through the first intermediate duct <NUM>, then through the second path <NUM> through the regenerative heat exchanger <NUM>, which is in heat transfer communication with the first path <NUM>, and through the second intermediate duct <NUM> to the compressor module inlet <NUM>.

The flow of working fluid results in the turning of the rotors <NUM>, <NUM> and hence turning the shaft <NUM> which may be coupled to a power offtake, and hence be used to drive another piece of apparatus, for example a generator.

The power output of the machine can be controlled through the addition and removal of working fluid from the system (increasing and decreasing the pressure and density of the fluid) or by altering the rotational speed of the rotor and shaft. Ideal positions for this which allow for addition and removal of working fluid without an additional compressor are shown in <FIG>.

In an alternative example, the thermodynamic apparatus may be configured to operate as a heat pump. In such an example the shaft <NUM> is driven by a motor to move the working fluid around the working fluid flow duct <NUM>, causing heat exchange across the regenerative heat exchanger to transfer heat from the heat transfer medium in the compressor to the heat transfer medium in the turbine. In such an example the compressor temperature would be higher than the turbine temperature.

The configuration of the apparatus of the present disclosure results in a heat engine or heat pump of increased thermal efficiency and power output, and hence one that provides reduced running costs compared to examples of the related art. Hence a thermodynamic apparatus according to the present disclosure will be smaller and cheaper than examples of the related art, giving a significant competitive advantage.

The internal routing of the heat exchangers of the compressor and turbine increases heat transfer and hence effectiveness of the cooling of working fluid passing through the compressor and heating are working fluid passing through the turbine.

The improved design for electrical power production marine or other propulsion arrangements (for example engines/power units for trains) of this invention can provide a benefit by decreasing fuel consumption (i.e. increasing the range or performance of vessels), by minimising the need for high pressure fluid pipework (i.e. providing a safe design concept) and by simplifying the supporting systems required to operate propulsion equipment (i.e. cheaper and simpler design).

The apparatus of the present disclosure is encapsulated in a single casing, reducing part count, overall size of the machine, reduced piping (resulting in lower losses), reduced sealing requirements, and removes the need for external regenerative heat exchangers. This improves the efficiency of the machine.

The turbine module and compressor module of the present disclosure may increase the thermal efficiency of a heat engine or heat pump in which they are included over currently available systems and has reduced requirements for space and supporting systems over conventional power generation and cooling equipment having similar thermal efficiency. This has the effect of making equipment of the present disclosure cheaper than the alternatives for the same power rating, giving a significant competitive advantage.

The apparatus of the present disclosure may be employed as constant speed machinery for electrical power production (for example where a heat source is created to drive a turbine). It may also be used in constant speed machinery for electrical power using fuels or heat sources. It may also have utility as variable speed machinery for marine or other propulsion.

Both electrical power production and the marine propulsion arrangements of apparatus of the present invention may provide benefit maritime applications by decreasing fuel consumption, and hence increasing the range or performance of vessels, by minimising the need for high pressure fluid pipework (making a safer product) and by simplifying the supporting systems required to operate the propulsion equipment (i.e. making cheaper and simpler design).

Claim 1:
A thermodynamic apparatus (<NUM>) comprising :
a compressor module (<NUM>),
a turbine module (<NUM>), and
a regenerative heat exchanger (<NUM>)
centred on a central axis (<NUM>), and
arranged in series along the central axis (<NUM>) such that the regenerative heat exchanger (<NUM>) is provided between the compressor module (<NUM>) and the turbine module (<NUM>);
whereby the thermodynamic apparatus (<NUM>) further comprises a casing (<NUM>), and the casing (<NUM>) extends around the compressor module (<NUM>), turbine module (<NUM>), and regenerative heat exchanger (<NUM>); and
the compressor module (<NUM>), turbine module (<NUM>), and regenerative heat exchanger (<NUM>) define a working fluid flow duct (<NUM>) which extends, in series, through :
a compressor module inlet (<NUM>) to a compressor module outlet (<NUM>);
a first path (<NUM>) through the regenerative heat exchanger (<NUM>);
a turbine module inlet (<NUM>) to the turbine module outlet (<NUM>);
a first intermediate duct (<NUM>) provided in the turbine module (<NUM>) to a second path (<NUM>) through the regenerative heat exchanger (<NUM>), which is in heat transfer communication with the first path (<NUM>); and
a second intermediate duct (<NUM>) provided in the compressor module (<NUM>) to the compressor module inlet (<NUM>).